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^3yke's Automobile and Gasoline Engine Encyclopedia 

Bound Willi G^niiino 
Leatbar Flexibla Binding — 

OoM Letters. 

Price $8.00 


(Add 46c to ««ad by iBsared 
mftil. If too much w« m\n 
refuDd dilTerwict,) 

Owing to the frequent demand of ] 
our customers oe former editions , 
— a limited number of copies of I 
this edition will be bound with a i 
high grade flexible binding — but 
otherwise there are no changes. 
To those who have purchased this ] 
edition (not former editions) with , 
the cloth or regular binding^ we \ 
will exchange, if in good condi- 
tion, on payment of the difference j 
in price and transportation. As 
Btated, only a limited number of 
the flexible bound copies of thiflj 
edition are available. 

Not« — If bcH>k It ft former edition add $B,00 

*'*%"vir£*,{SSl^"^° DYKE'S MOTOR MANUAL phc* $2.00 

All about StftiioiLary IntemiLl Oombustloa Engines (gas^ gaaolioef kerosene, oU) Mulne 
EnginM, Motor BoatB^ Motorcyclea. A Submarine^ also Gas Produeere are explained. 
Quite often the Automobile Eepairman or Owner ie ealled upon to diagnoie troubl#iL ^rj 
repair Stationary, Marine, Motorcycle BngiiieB— are you fully potted T Tbii Motor Maa- 

ual will teach you— get it for a reference, if nothing more. 


[ Motorcyclci.Mmi inr 

Simplified f 


PQltj illastr«t«d, 3S4 

r<*tl*%l **>%<*% 

-iHttl toAkVf - 


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tMn <aiif4<r •p»«4i«» • 

Tb»it I wo iUttfttntioae gitt ah ld«« how »11 Ulaatrklioiu ar« 1 

ffttort And CPoili— tvad 10 A. U Dyk*. Pub,, Oreolte Btdg. (Bl«ctrle 

fWJinV, " ,37 COLOEN CATC AV t. yy 


Giving the Page Number Each Chart Page is On. 





















































































OkM% Ptg« 

































































OkM% PAff« 

148 289 












































176AA 369 
176B 360 




























1887 408 

OkM% Ptg« Oharl Pact 







































































Vq. 1, paff« Ite; Va. S, pag* 
















































































































































































817 776 














829 782 

380 783 

881 784 

888 786 

-88a; Va. i. 864*. 













































Pg. 90f 


Automobile and Gasoline Engine 



Second Run 

Containing 532 Charts, Inserts, Dictionary, Index, 

and Supplements on the Ford, Packard, Airplanes, 

and Liberty *M 2" Engine. 




Also Trucks, Tractors, Airplanes and Motorcycles. 


A. L. DYKE, E. E. 





"DYKE'S MOTOR MANUAL;" all about motorcycles, marine 


0op7rifbt«d 1011-191219181914-1915 1916 1917 1918-1919 1920 


All Bifhti Reserred. 

OopTriElit ProteeUd in Great Britain, all of her Ooloniea and Canada. 

Entered at Stationers Hall, London. 

Platei made, type aet and printed in U. 8. A. 

All Bifbti Reierred. 


A. L. DYKE, Publisher 

ST. I.OUIS, U. S. A. 

I f- 9-9:) 

of lih 

colored page imert in bmek < 

first pcge flj leaf of book« 

'or IHcMitiurT- 

VtLge Wl. 



ss* so 

Dtff«r«atUa aod B««Elllfl. . SI- 96 

i^-<Ilfiteli«i^ UotTfnal Jomtft 37- 4i 

# — Ttt**^'"* «f ftiw* ,,««^., . 4i^ 51 

y »q M aari J Ccnvtmctloii ...,_.*.., fiS- 71 
•— PiiBcipte. IjocAtiim of Pirta.... 7S- d2 

i^V&lv« Timing ,,., ,,..-.♦ 93-115 

10— nftQ< Order ->.,... ..,_...,..,U6-120 
U-^au, mgut wd Twitv# O^UndAr 


OoBVtrucUon , , .141-166 

IS^-OBftmratar Adjuftaiinti 166-lBi 


.*-.. lee-iw 

OUfl ftud QfViMi. . ,186^206 


IS— l4>w Touilciii WT^UaoM. .906-S17 

17^--aiffb T«ti^^a BfBtenui . . , .216-232 

li^^Spmric Flag uq4 PoO Trtmblif . . .saS-Sil 
l^^Hodvm BAttary and CoU STstetos . 242-2M 
HO^Bilaf Ettn«w of tao Vartoiu OM 

B^mmoM 866 

U— I^ow TttUloii. (Piliu:liil0 And Oom- 

ftmctloa) ,.,,..., 26d-S67 

IB— HlgJi TOsDfltoa (Xjoftdlnff tTpet d»< 

ionbod) ,. 266-293 

86— lnat«JiAtloii, 0»i« «tid AdJiiAmiot8.2M4-304 
ii^-l«iatlcm Tuning , _ .30&320 

16— Baglno StArten .,..,...,...... .621-622 

ii^Tlis Eloctxlc 8ta4l^lng Motor 393-331 

i7— TtM G«nerKtar. (Source af CTor- 

tm%} .,.__.. _ .332-656 

iS— Typai of StartlQif and G«2iorAtliiS 

HfitOimi uftod OQ lieadlng Qui S66'^^73 

aiA-Daloo £&rlj IgnlUon ajmi«iDS. . . .374-376 
MB-IHixso Modern Xgnltioa, itAitlD^ 

•ml li&gHtUig Bj&tmaxE 379-396 

mO-Gt^ Twts And AdJovtlnAKiti of 

IMIOO Mytt/ttHM , , , .397-406 

tt^-Ome% TeotA iJid AdJusUotiiti of 

mhm liMdiUff 8yit«u. 406^424 

30— Win&g A Oar. ... ...... .42fi-429 

51^ — IJfliyng a dkr .*.....,...* 460^436 


32 — itorago BattKtn . _ .439-466 

S2A-moTl«e Ban«r7 E«palj^^. .46#47SS64S 
33— Elaetnc mnd 0afl^Bl#ctric 7«Atidai 476-464 

34 — Operatljif a Ou .............. .486n600 

36 — Exiles of tim Boad • . . . .601-604 

36 — Care of Car ...,-.,-.,,.* .606^0 

37 — Accessorlee. Touring 611-620 


38 — Insoraiico. Lk«nse and I^awt 521-626 

39 — TIte Aatomoblle Saleeman. 629^^33 

^>— BoiBi Power Xablea and CHneiral 
DatA. Standard Adju^tiiieELtA of 
Leading Cars. Sp^cHlcaMooi of 
^f*M1ng Cars _ 

41 — Tlrea. Air Foinpe and €ompc««eorB.54fr-G64 
42— Tire EepairEng and Care of .666^976 

46^-Dlgeet of Trouble* _ .676-661 


44 — Tile Automobile Eopainnan ...... B(Pt fSOt 

45 — Gara^o and Sliop Bquipmenta. . . .596-619 

46— Bep^ring and Adjufitlng Emglnee. 620-609 
iSA-AdJniftliig dutcbee, TranAmlHloii% 

Boar Axles and DUf erentlaLi 660-679 

46B-AdjU9tliig Wbeela, Brakes and 

Steering _ , .680-694 

46C-1IOW to Vm Tools and Make B«- 

paliB. Oxj-Acetyletno WeldJng. . . .696-729 
46D-1Tft^al Sbop Hints and Bo'rlcia. .730-744 


47^ — Commercial Cars 746-781 

46 — Tbo Tractor , 763-764 

49 — Engines; different prindplat 750*76A 

49A- Addenda; Tractors, Truck Engines 
and E^pair^; OoTemors^ Motor- 

c^rclee, Eepalxlng Tops, etc 829-649 

BO^Dlddonary of Automobile Term*. .861 864 


Tbo Ford ......,,. 766-628-864A 

Tbo Packard— "3-25' ' ft "S46". .., .860-661) 

Airplanes 900-928 

Wiring Diagrams . . 923-921 

K. W. Magneto Supplement. ........ .928-030 

ladM ............................. .867-891 

Liberty Engine Supplement. . . . . .933-940 

Tlitre are serireral Inserta dealing wltlii En^ 
glnei, Modem Cars. Dixie Magneto, Motor- 
crclei, 9tc. . 

Use the Index- -refer to it often. Any trouble you may have, refer to indox. Stn^ 
544 for SpediicationB of Tiimding Can. 


The Selation of the Antomobile, Trnok and Traotor. 

Although this book was originally prepared to deal with the passenger 
car type of Automobile, the subjects of Trucks and Tractors have been added 
and right at the beginning, it is the purpose of this introductory, to point out 
to the reader the close relation of the Automobile, Truck and Tractor, so that 
when the study of the book is completed he will clearly understand the differ- 
ence in construction. 

In addition to the Truck and Tractor subject, the Airplane and Airplane 
Engine is also dealt with. 

The same underlying principles of the Drive System of an Automobile are 
used in the Truck and Tractor, but of slightly different construction. 

The same underlying principles of the Automobile Engine are used in the 
Truck, Tractor and Airplane Engines, but of slightly different construction. 
With this in mind, it will be easier for the student to understand the differ- 
ences as he progresses. 

Why the Instructions Begin With an Early Type of Oar. 

In order that the reader may clearly understand the details of the modem 
automobile and its parts, it was necessary to illustrate and describe the early 
type of cars and gradually work up to the more modem tjrpe. For this rea- 
son many of the subjects begin with early models or types, which is absolutely 
necessary before the reader can properly master the subject. 

The reader will learn the principles of construction of the different parts 
of all automobiles in general use. The constraction may vary, but the under- 
lying principles remain the same. Consequently when the reader masters the 
principles involved, he masters the construction of all types of automobiles, 
engines, ignition systems, carburetors, etc. 

The illustrations are not drawn to scale, in fact, the majority of the illus- 
trations are exaggerated in a great many instances — in order to clearly de- 
scribe the subject treated. 

The writer makes no attempt to treat the subject in a theoretical man- 
ner, his idea being to adhere strictly to the practical side of the subject. 

For many of the illustrations and much information to be found in this book, the 
writer ia indebted to th« *' Automobile, " of New York, *' Motor Age'* of Chicago, '* Auto- 
mobile Dealer and Repairer,'* of New York, and *' Motor WorW of New York, as well 
ai a great number of manufacturers of automobiles and accessories. 

A Hodern Track, 

Tho prlndpl^ of the txnck ie nmiiiir to 
tbe [iriticiplo of a passf^Bger car type auto- 

Th.9 englDfi iv usuaUj" a four cyUadar tjrpe 
of engiue^ for roasoPH explalaed on page 
747* Bee aliO] ptig® 71, Tbo truck en^i^e 
is a slower speed engine tkaia the autom<H 
bil@ engino. The avorago maximum speed of 
a truck ongioe is 900 to 1000 r.p. m. The 
sngi&e speed is controlled b^ a hand throttle 
aaU foot acccjlerator, the same as the auto- 
tnobUe engine, Uut a govtrnor la employed, 
far reasons statod on page SSS, wbieli is to 
prevent undue '* racing'* of engine when 
changing geara or releasing clutch. 

Bit gOTttmlng tbe engine spaad, tbe car 
sp^ed Is alao limited* for mstapce^ the gov^ 
ernor can bo sot to govt^rn tlie engine speed 
at 960 r. p> m. wblch gives a maximum car 
speed of II m. p. bi, whkb is the average 
speed of a heavf dutj truek. 

The 8p««d of a paaitng ST tyft aulomoliild 
varies from 1% ni. p* h. to 60 or 60 m, p, h. 
and a governor is not employed. The ongine 
•peed of a pasneiii^er lyim automobile varies 
from ISO r. p. m. to as hlgli as 2600 to 3000 
r . p. m , The trucks however, being d es Ig a ed 
for coiumcretil use must neccsitarity be more 
efficient, hence the empluymt^nt of s goveroor. 

All oompllcattd devices are ellmlnatad on 
a tmck, tor thf sako of afflelaiiay* For In* 
slaneoi the electric iilarting motor is seldom 
used, iustoad, the engine is aratik«d bf liaiid 
In connect ion ivitb an ** impulse starter" 
(sea page 747 and S33). Instead of a coll, 
batter/p generator, cut oat» timer and dis- 
tributor being used far Ignition, a high 
tension mngneto is nsuaUjf emptojred. The 

gravity fuel feed system is naed instead of 
vacuum or pressure feed. The tubular typi 
radiator (page 190), for cooUng ia used in- 
steafl of the cellular type. The cellular type, 
as generally used oo automobiles, Is mors 
artistic in appearance, but the tubular typfl 
has larger openings and is less liable to clog 
and easier to repair. 

i,*.??r71ffh*???. I* usuilljf by 1 propeller ih«ri eom 
WGrm geATi\\U] on aiJT«^r,.mifl|. The worm gw 
fJTBi ft gTtmUT reduction sDd ii itteot mud tni- 

B«r szlB if uiuallr a fall flontiiiff ' 'Uvb' ' »1i 
(F). 8f« ^so, p«irfi 761. 

iti4 reT#ri«. ud Is ftitnilmr to aa ftiUomobile tmni' 
iniRsioii, ^ut of hs-ftviflr tonptnictttm. Q*»r ralles' 
Oq ftboTA truck {Waster. modvU M & O) flfM 
ffjeed, rtjar whe^Ia niftke \ rtvcilutioQ to sv«i-y 24 

WgCjlil 1 tl r^'"*' '*™^ ^^' ^ **> ^^■*' 

ttpU di.« t^pe. Tb* clutch .Cw* a7p^«„*%?^ta 
siienaiTBly titsd ii la alao the coa« typS clutch. 

front: ie-i7- r#.r. Tbe '^duar" loHd tir*, *|i 

tha ■ pn«i«atie eerd'' truek tire, pw- pat? si* 

afa alio attsaslT*!; at«d. '^ ■ ^""' 
SlaaHei t« the Hoaa, pag* 69 o, 

clfls ef lb» paaiwi,^ car trpa of aatomobUa 

Ptan witw ttf Cmat J7-2S trveiar ttn'ming t^gout ttf trantmtniom Aii4 4nvt 

The Modern Tractor, 

The purpose of a tractor is explained on 
pifei 753 and 831. Note that in addi- 
tion to doing tractor work« such as pulling 
plows or other drawbar wurk, it is also 
|K>»ib]e to do belt wor^ auch aa operating 
threshing machines, etc. 

Tlie above iUustratlon Is that of a four- 
eiUnder engine tractor* Most all tractor 
•Bgiaes are four-cylinder^ for reasons ex- 
pUiDed on page 831. 

Tbe construction of a tractor dlifers con- 
Uderably from that of an automobile or 
tnudt, but the same underlying principles of 
eigiae and drive system are employed. 

the engine used on a tractor is a slow 
•P^ engine, and usually a large bore. This 
pwtieuJar tractor engine has a bore of 4% 
in. and 6 in, stroke. A governor is employed 
^6r the purpose as explained on page 839. 
Tht ij»6ed of engine is governed to 900 r.p.m* 

Tbc Ignition is usually a high tension mag- 
wta with an *• impulse starter*' (see page 
112 for explanation of an impulse starter), 
^oit tractor engines use magneto ignition 
r<>r reasons stated on page 831. 

The tractor engine operates for long 
Modi of time at full power, therefore must 
^ built heavier and more Bubstnotial than 
lit* automobile engine, for instance in the 
l>«tfiEgs, etc. 

Fuel IT* usually gasoline to start with and 
Woiene to run on, after engine has started 
tsd became thoroughly heated. The lieatlng 
of a tractor engine, in order to use kerosene 
ar low grade fuels is a very important fac- 

tor—see pages 827, 828, 831 and 71. 

Drive system. The engine on above trac- 
tor is a four cylinder, vertical type, mounted 
transveraely on the frame. The power from 
crank ahaft is transmitted to the spur gear 
transmission by means of a clutch. From 
transmission^ power is transmitted to the 
rear axle by means of a spur gear drive. 
The differential is employed as shown in 
illustration. Power is transmitted to both 
rear wheels^ which are 62 inches In diameter 
and have a 12 inch face. 

Speed of an average tractor is 2 miles per 
hour on slowest speed and 2% m. p, L. on 
high speed — see also, page 830. 

The belt power is obtained from a 16 inch 
pulley mounted on an extennion of the engine 
shaft, and therefore runs at engine speed — 
900 r. p. m. 

The above tractor (the Case 15—27 h. p. 
tractor) has a wheel base of 76H i*»M ^^^ 
its overall dimensions are: Length, 126 in.; 
width, 72 in.; height (without exhaust pipe), 
68 in. The shipping weight is 5500 lbs. 

Tb© tractor puUs three 14-in. plows m 
tough sod or four plows under usual CDiirli- 
tions. It ie also adapted for other drawbar 
work (see page 752), requiring a similar 
amount of power, and it will operate either 
a 20x36 or 26x46 in. thresher (belt work). 

It will be observed that the tractor, while 
It dlfrers widely in construction, from that 
of the truck or passenger car automobile, it 
is, in many respects simUar in principle, the 
main dllterence being in the drive system 
and fuel used by the engine. 



Front Axle 1 

Steering Knuckle Pivot 2 

Steering Knuckle Arm (right) 3 

Steering Knuckle Arm (left) 4 

Steering Knuckle Tie Bod 6 

Steering Gear Drag Link 6 

Steering Knuckle Gear Bod Arm 7 

Bmut Azla (Housing) 8 

Differential (inside of case) 9 

Axle Drive Bevel Gear 10 

Axle Drive Bevel Pinion 11 

Axle Drive Pinion Shaft 12 

Axle shafts are inside of axle housing. 

Brakes on Hub of Wheels ('Operated 

by Hand Lever) 13 

•Brake on Drive Shaft ('Operated by 

Foot Pedal) 14 

Brake Bods 15 

Brake Pedal (Bunning) 16 

Brake Lever *. 17 

i^Eingi 18 

%>ring Blocks or Seats 19 

luring Clips 20 


ICain Frame 21 

8nb-frame 22 


Body 23 

Fenders 25 

Banning Boards 26 

Dash 28 



l«wa bnk« 


(Four Cylinder) Cylinders Cast in 

Pairs 39 

Inlet Valve Caps 40 

Exhaust Valve Caps 41 

Crank Case (Split type) 42 

Starting Crank 43 

Flywheel 44 

Inlet Manifold 45 

Exhaust Manifold 46 

Exhaust Pipe 47 

Muffler 48 

Cooling System. 

Pump 49 

Badiator 50 

Cooling Water Inlet and Outlet 51 

Fan 52 

Fan Belt 82 

Ignition System. 

Magneto (High Tension type) 53 

Magneto Drive Gear in Engine Gear 

Case 54 

Ignition Switch 55 

Spark Plugs 56 

Cables (High Tension Ignition) 57 

Fuel System. 

Fuel Tank 68 

Inlet Manifold 46 

Carburetor 60 

Throttle on Carburetor 61 

Fuel or Gasoline Pipe 62 


Steering Post Assembly. 

Steering Column Tube 63 

Steering Gear Case 81 

Steering Wheel 64 

Steering Gear Arm 65 

Spark Hand Lever 67 

Steering Gear Connecting Bod 6 

Throttle Hand Lever 68 

Spark and Throttle Sector 70 

Spark and Throttle Control Bod 71 

Throttle Lever Shift Hod 72 

Hand Lever Assembly. 

Gear Shift Lever 73 

Brake Lever 17 

Gear Shift Gate or Selector 76 

Gear Shift Lever Shaft 77 

Pedal Assembly. 

Clutch Pedal 33 

Brake Pedal 16 

Clutch and Brake Pedal Shafts 78 

Clutch Belease Fork 80 

praetiet ii to hfty« Hand Xiever operate the eztemal brakes and Foot Lever the In- 
— both on rear wheels. 

Gear Box or Goar Set 29 

Cover Plate for Transmission 30 


(Cone Typ«) 31 

Clutch luring 32 

ClQteli Pedal 33 


Universal Joint (forward) 34 

Universal Joint (rear) 36 

Drive or PropeUer Shaft 36 

Drive Pinion Shaft 12 

Differential Driving Pinion 11 

Differential Driving Gear 10 

Torqne Bod 37 

HO. a— Key to Motor Oar Parts; illustrated in Charts 1, 3, 4, 5, 6, 7, 8, 9, 10. 
81 and 32. 

i: Modam type of can will be shown further on in thif ^ook. R/ad hiding top of pafe lY. 





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THE AUTOMOBILE: Assembly of the Automobile. Fiinctions 
of the Principal Parts. 

The Kinds of Motor Cars. 
There are three different kinds of motor cars; first, the gasoline motoi 
car; secondly, the steam car; thirdly, the electric car. 

The gasoline motor car is by far the most popular, and it is with this thai 
we are mainly going to deal. 

The steam car, silent, smooth and easy on tires, is comparatively seldom 

The electric car, almost invariably in the form of a brougham or coupe, 
is heavily handicapped by being unable to run for more than a few hours 
without a fresh charge of electricity from its headquarters, and is quite in 
the minority. Our attention will be devoted to the car with the gasoline 
engine for the motive power. 

The Component Parts of a Motor Car. 

A car may be made up as a whole of two distinct parts, the body and 

The body, which is the work of the body builder, which has been brought 
by him to a wonderful pitch of perfection, hardly concerns us so we will un- 
screw the half dozen or so bolts that secure it to the frame of the chassis and 
stand it to one side, for the present at least — so that we can examine the 
chassis underneath. 

The chassis is the entire car with the exception of the body (see chart 8)'. 
The chassis, for our purpose, must also be divided into its main parts as 
follows: the running gear, power plant, transmission system, control system, 
equipment and accessories. 

The running gear consists of parts as follows: front and rear axles, 
wheels, springs, frame. 

The power plant consists of parts as follows : motor with its fuel system, 
carburetion system, ignition system, cooling system and lubrication system. 

The transmission system consists of parts as follows : clutch, change speed 
gears, drive shaft with its universal joints and differential. 

The control system consists of parts as follows : steering device, throttle 
and spark control, kand levers, foot pedals and brake system. 

The necessary equipment consists of such parts as fenders, running 
boards, hood, dash, tires, lighting system, self starter, horn, etc. 

The desirable equipment or accessories are such parts as speedometer, 

windshield, warning signal, shock absorbers, etc. 

The construction of the parts of a motor car may vary, but their purpose 
is the same. While it is true there are hundreds of different firms making 
automobiles, they all employ in the construction of their cars the parts en- 
umerated under the various headings. For instance, one manufacturer may 
suspend the power plant on the main frame, others use a sub-frame. Some 
use a clutch of the cone type, others use a clutch of the multiple disc type — ^but 
they all use frames and they all use clutches. Further on we will explain the 
different constructions involved in these parts, but bear in mind the principle 
or purpose of each part does not change. 


As we progress the reader will gain an idea of the different constructions 
of the component parts now in general use — for instance, there are two kinds 
of front axles in general use; the tubular type and the solid type. There 
are two types of construction of rear axles in general use; the live axle 
which revolves and is driven by a bevel gear and pinion, and the dead axle 
which does not revolve, but the wheels are driven by chain and sprocket, and 
so on, throughout the whole construction of a car. 

*It is now clear that if the reader masters the principle and purpose of 
these parts then it will be no difficult matter to understand the variation in 
construction, and when he will have completed the study of this construction 
he will have gained sufficient knowledge to enable him to understand the con- 
struction of all cars. 

Purpose of the Parts of the Running Gtear — see chart 4. 
The front wheek run free on the axle, and guide the car. They are called 
the guiding wheels and are moved from side to side by means of a steering 
device (63-64-65) and the direction of the car is controlled in this manner. The 
rear wheels are revolved by the engine and drive the car. 

The front axle is fitted with steering knuckles (3 and 4) on which the 
guiding wheels run. These steering knuckles are moved by means of the rod 
(6), which connects to the steering device (65). The front axle is fitted with 
spring blocks (19) and spring clips (20) which hold the springs in place. 

The rear axle revolves. The housing over axle is fitted with spring blocks 
and clips similar to the front axle. 

The springs act as a cushion and protect the machinery and the occupants 
of the car from undue vibration and shock. They also hold the frame. 

The frame of an automobile is made of pressed steel and is the founda- 
tion which supports the power plant, 
change gears, levers, steering device, 
fuel tank, body, etc. Each part is 
bolted to frame and is kept in proper 
relation to each other. The frame 
is usually hung, with the springs rest- 
^ ing on the axles as shown in upper 

Fir. 1. In the upper illustration is ghown the iHuStratioU, fig. 1, tO the left, Callcd 

•nratang spring suspension which is used on the OVerslunCf. SomctimCS the SprinflTS 

■siority of the cars today. Note that here both r^ji-i xi. -i n-i 

front and rear sprincs and also the frame are above are laStenCCl belOW the axlCS, Called 

the axles. la the lower illustration is shown the fU^ iinHprflliiTiir pnnGfi*ii/>finn 

■adenlnng. a form of spring suspension in which ^"® UnuerSlUng COnStrUCtlOU. 

tbe frame is above the axles, but the springs below a i^ ^ ^- i -i 

-teidom used. A suD-framo IS somctimcs placed 

A popular spring system is the cantilever, see insidc of the main frame tO SUppOrt 

the power and drive plant. 

The steering device (63-64-65) is usually attached to the frame. By turn- 
ing, the wheel (64) the car is guided through the control of the direction of 
the front wheels. 

Brakes (13) are fitted to motor cars for stopping or slowing down and 
^ usually fitted to a drum on the hubs of the rear wheels. 

Purpose of the Parts of the Power Plant — see chart 5. 

The engine furnishes the power that drives the car. It is usually located 
^the front part of the frame, if it is a multiple cylinder vertical type of engine. 

^SHKpension: multiple cylinder engines usually have four, six, eight or 
twelve cylinders. If it is a single cylinder engine, it is usually hung as shown 

*8«e index for advantages of "three point suspension." 

*Th« tjpe of clateh, axle, engine, etc. which are used on leading cars given under "Spceificatioas 
« Uadiag Oart*' — page 542. 



in chart 11, fig. 1 ; if double cylinder opposed type, it is usually placed across 
the frame. If a multiple cylinder, "single unit power plant" (see page 85), 
it is usually suspended at three points as per page 786, fig. 49. This is called 
"three point suspension." 

The carburetor mixes air with gasoline, and is connected direct to intake 
pipe on engine. The carburetor is connected to the feed pipe (62) from the 
gasoline tank. 

The gasoline tank is usually placed under the seat or at the rear of the 
car and gasoline is fed to the carburetor through a small pipe (62) (chart 8) 
or by the vacuum system (see carburetion instruction). 

The exhaust pipe (47) connects to the exhaust manifold and runs to muf- 
fler (48), which is usually placed at rear of car. The exhaust pipe permits the 
burnt gases to escape. The muffler placed at the extreme end of the exhaust 
pipe, silences or muflfles the noises from the explosions in engine cylinders. 

The ignition system is a part of the electric plant; either a storage bat- 
tery and coil, dry cells and coil, generator, or a magneto. The coil and battery* 
electric system was formerly placed on the dash, while the magneto or genera- 
tor is placed on the engine and is run by the cam shaft or crank shaft, through 
the medium of silent chains. The modern coil and battery system with a 
timer and distributor is now placed on the engine, see Delco and Atwater-Kent 

The cooling system consists of the radiator (50), water pipes (51) and 
circulating pump. The object of the cooling system is to keep the engine 
from getting too hot when the explosions take place inside of the cylinders. 

The lubrication system of the engine is for the purpose of keeping the 
bearings and rings and other moving parts from wearing. This subject as well 
as all other subjects will be treated separately further on. 

Transmission of Power— see charts 6, 7. 

The transmission or the speed change gears is that part which transmits 
the power from the engine to the driving wheels through a system of speed 
change gears (29). 

A clutch (31) is placed between the engine and transmission; this permits 
the engine to run free, or when ** thrown in" connects the engine to the change 
speed gears and drive the car. The clutch is operated by a foot pedal (33) 
and is thrown in or out by the driver. 

In a locomotive, the piston rods are connected direct with the wheels, 
through the medium of the cross head, and connecting rods so that when 
steam is applied the locomotive moves. In an automobile, the engine may be 
disconnected from the transmission by means of the clutch, so that the motion 
of the transmission or of the entire car may be stopped without stopping the 

Change gear principle: When a bicyclist wants to race on a level track 
he gears his wheel up high, so that one revolution of the crank takes him the 
greatest possible distance. Yet if he takes this wheel on the road and en- 
counters a hill, he must get oflE and walk or exert an extra lot of power — ^he 
needs a wheel geared lower. 

In the same way, when an engine is required to do more than ordinary 
work, as climbing a hill, the transmission or change speed gear contains from 
two to four changes of gears and helps out the engine by changing to the gear 
ratio required for less motive power. It allows the car to move at various 
speeds while the speed of the engine is unchanged. 

When in low gear, the engine makes quite a number of revolutions (15 
or 20), while the wheels revolve once which makes the auto move forward 
slowly, but with considerable force, so that it can go up a steep hill or through 
sand or mud. 


When in second or intermediate gear, the engine makes from (8 to 12) 
revolutions to one revolution of the wheels, which moves the car faster than 
the low or first change of gears but with less force. 

When in third or high gear the engine makes from (2 to 4) revolutions to 
one revolution of the wheels, which gives the car high speed over good roads. 

If the car was going up a steep grade while on high gear, the work 
would be more than the engine could do, and it would stop unless one of the 
lower speeds were shifted in. There would be considerably more pull on the 

The operation of the change of gears is by means of a side or center lever 
(73, chart 1, also see chart 23) ; change of gears can be made instantly. The 
transmission also contains a set of reverse gears, which when thrown in, will 
reverse the motion of the car without reversing the motion of the engine. 

The transmission may be connected so that it drives the wheels by the 
following methods. 

First — ^by a driving shaft (see chart 11, fig. 1, c and e, also (36) chart 6), 
connected to the rear axle, which it revolves by means of bevel gears, the wheels 
and axle turning together. This axle revolves and is called a "live" axle. 

Second — by a single chain (see h, chart 11) connected to the rear axle, 
wheels and axle turning together. 

Third — ^by two chains (see b, chart 11), one connected to each rear wheel, 
which run free on the axle, like a buggy and is called a "dead" axle because 
it does not revolve. 

The Drive System — see chart 6. 

The connection between the engine and the w^heels is called the drive 

The drive shaft connects with the end of the transmission shaft by means 
of a universal joint, it has also a universal joint at rear end connecting with 
the differential drive pinion shaft. • 

The universal joints (34-35) permit the parts mounted on the rear axle to 
move up and down, thus preventing the movement of the axle from interfer- 
ing with the drive of the car. 

The torque rod (37) is usually placed between the housing on rear axle 
and the transmission case. The object of the torque rod (or torque arm as it 
is now called) is to prevent the axle housing from twisting when the power or 
brakes are applied (see page 22). 

The drive pinion shaft (12) connects to the rear universal joint (35) 
and drives the bevel gear (10), which is connected to the differential (9), 
(see chart 5). 

The front wheels on an automobile run free on the axle. For this rea- 
son the outside wheel is able to revolve faster than the inside wheel when the 
ear is turning a comer. 

When a vehicle turns a corner, the outside wheels revolve faster than the 
inside wheels, because they travel a longer distance. 

The wheels in rear must do the same thing ; if they were forced to revolve 
at the same speed, one would slide because it could not keep pace with the 

When they run free on the axle, they would take care of this them- 
selves, but as both are driven by the engine, the transmission or rear axle is 
fitted with a differential, or at times erroneously called a compensating gear 
(see chart 18), This device is automatic, and permits the wheels to revolve 
at variable speeds, although both are driven by the angine. 



Power PUnt Drive Shaft , 


Universal Joint 


DriTo Shaft 



Fig. 1 — ^Methods of Power Transmission to Bear Axle, 
h — Single chain drive (obsolete), b— Double chain drive (used principally on trucks). ^- 
Shaft drire with a double opposed type of engine (shaft drive is extensively used, but the opposed 
type engine is seldom used), a — Shaft drive with a four, six, eight or twelve cylinder angina 
(extensively used). 

Fig. 2 — Top Tlew of a doable chain driven truck. Rear axle is called the "dead** type because 
it does not revolve. Formerly employed by the Packard Motor Oar Oo. 

Fig. 8 — Side view of a modem Packard chainless truck. Drive; worm: power: four eylinder 
gasoline engine; clutch; disk: transmisBion ; four speed selective sliding: "live" rear axle; full floating. 

Worm gear drive. This system is used on a large number of cars now, especially on tmcka, 
and is coming more into favor every year. There is no diflterence in the transmission system, OKeept 
aa regards the drive, as compared with the usual bevel-gear system. In principle the worm drhre 
is a simple arrangement; the usual bevel gear and pinion are replaced by a specially-shaped hoUvw 
helical toothed gearwheel and worm. A "live" rear axle is used. 

NO. 11— MatliodB of Trangmlwilon of Power to Bear Axle and Bead Whetls. 



The automobile frame, with all parts of the running gear, the transmiB- 
non, engine and other parts of the mechanism, when it is wifhont the bodj 
11 ealled the chasds. Different types of bodies may be attached to a chastii, 
ind are generally fastened down with bolts. 

The bodies of pleasure automobiles are classed as follows : 

Boadster — ^An open ear seating two or three. It may have additional seats on rmn- 
niig-boards or in rear deek. 

Ooapelet— 9eats two or three. It has a folding top and full-height doors with diaap- 
ptiring panels of glass. 

Coupe— An inside operated, enclosed car seating two or three. A fourth seat facing 
btekward is sometimes added. 

Oomrwrtlbla Oonpe — ^A roadster provided with a detachable coupe top. 

Cnowr I«eaf — ^An open car seating three or four. The rear seat is dose to the divided 
front seat and entrance is only through doors in front of the front seat. 

Tonztng Oar — ^An open car seating four or more with direct entrance to tonnean. 

Btlon Touring Oar — ^A touring car with passage between front seats, with or without 
nptrate entrance to front seats. 

Oonvertible Tooilng Car — A touring car with folding top and disappearing or remov- 
iUe glass sides. 

Sedan — A dosed car seating four or more all in one compartment. 

OUiYartible Sedan — A salon touring car provided with a detachable sedan top. 

Open Sedan — ^A sedan so constructed that the sides can be removed or stowed 
to leave the space entirely clear from the glass front to the back. 

Umonslne — A closed car seating three to five inside, with driver's seat ontdde, cov- 
•red with a roof. 

Open Idmonsine — A touring car with permanent standing top and disappearing or 
naovable glass sides. 

Barllne— A limousine having the driver's seat entirely indosed. 

Brongham — ^A limousine with no roof over the driver's seat. 

Landanlet — A closed car with folding top, seats for three or more inside, and driver's 
Mtt outside. 

Body equipment consists of a hood or bonnet over the engine which con- 
nects with the dash of the body. Fenders or mud guards are usually attached 
independent of the body, also the running board. Wind shields are placed in 
front on the dash. Steel pans, which extend under the mechanism, protect- 
ing it from mud and dust. 

Commercial vehicles are those used for business purposes such as taxi- 
cabs, delivery and trucks. 


Tires made of rubber are fitted to the wheels to take up the vibrations 
that are too sudden for the springs to absorb. 

The wheels of an automobile are smaller in diameter 

than horse drawn vehicles, due principally to the fact that 
at the high speed the automobile travels, the wheels would 
have to be built entirely too heavy to sustain the strain. 
Automobile wheels must be very strong, because of the 
weight that they must support, and the strain that they 
are under. They are made of wood or wire (see illustration). 

Wooden wheels are made with a wood felloe, over 
which fits a steel rim that holds the tire. It is called an 
artillery type wheel. 

Wire wheels are light, easily repaired and are becom- 
ing very popular. 

Mud guards or fenders are always fitted over the wheels, to protect the 
ear and occupants from the mud thrown by the wheels. 


AttJiongli Itacn KM muij tiwelal nukM of bodi«i whicb «rs i^ivcd irpecial natDPR, th*? aiit 

will fi^e thfl reader lbs nmmet of the atmndBrd tjF|ie of bod Leo, 

If^« tb« Oyelt OftT U tiow c&ILcil ii Lilgbt 0»r. 

TtiB Sftdui dif7i;ri from the Llmouaioe ia tli*| th« dHirei-*ft t^nt Id tKe Sed«.iEi is plactid in 
itftta and would b« termed a family ear, Tb9 owner quile oHcn drl^ei thii typr of car. 

Til* liiancmiilM front a»»i la paTtltion««l off from arata In iht rear and is uNuaUy 

TIm Town C«f i« • lifbi, low, tKoH wbe«l bue, witb chaaff^ur'i seat in front. Thia I 
lued for T^ilejab iarvica. 

¥b« liftndma la m trpe of e*r itasfUr to tb« Litnouiioe, but tbe r«ai- pari of top can 

Tb« dlMtBeUon b«tw«ta tlM ]>«UvaEf wicoo a&d TrndG ia io aiifs and weight. Th« 
ia tisualb a shaft drlT«o ]>nemii«tl« tired car, whoreaa tbe truek is a double ftiain or nUaft di 
bea^y m*chLtie. ^ 

OHABT NO. 13— T7P«i of Bodies. 

CLUTCfl «1A]I 

Buick Six. 

Tlie Bulck 1918 line vr^v compoitd 
of thre© modelft. Two sixot. Th« 
only mAterial difrereoce wat in tht 
wheel ba«fl, 11 B" snd 124* — ^tha ea- 
fcine being the tame. 

The 1920 Buick ILm is comp«ied 
of iix models of cArs: Model K-eiz- 
44, a lhree-pa»«enger roftdeter; model: 
K »ix-45. a fivepasftenger touring c»r; 
K-aiX'46, a touriog coupe; Kffix-47, . 
a fiv^e-pasiengcr tourio^ sedao; K-tix- 
49, tt «ev«a-pasaeDger toaring car; K- 
Rix'50, a aeven-peascDger sedao. 

Eagl&i oo All model! ia the same tlx 
cylinder type with valvea-io-tb^-bead.j 
:i%" bore by 4^" itroke. aemi-itMr 
bloc casiiugB. YaUfss are moaDled ia 
cageA — ai'e page lOP. 50 actual brak*- 
horao • [iower. Oooliog, ceatrifugal < 
pamp and cellular type radiator; ' 
lubrication, circubtlog epiaali ofier* 
Aledi by gear pump driven by tiiiral, 
gearB from cam ehaft; cvboretor ii 
the Xtarvel ihown on pai^e 179, witk 
rarnnm fuel fv^(\ Ryitetn explained ofi 
page 105; ignittoo, high tension Jump 
apark system — Delco electric ayttcmi 
Detuo Hinglft wire. Clutch* multiple 
dise, dry plate: transmUslon, 3 8p«ed 
nnd reverse. 8.36. 1.76 and 1 to 1 os 
firsts second and third fe&rs, and 411 
to 1 on reverse, nf^lActive typtr lea 
page 497 for guar uliifti rear Kd«. ftiU^ 
floatinir type with 4 to 1. ratio oa 11B'| 
wheel bane and 4.<S15 to 1 on the 114* 
whoel bftBP car — see page 557 for typ« 
of rim used. 



Automobiles are required to carry two lights in front, and another, called 
the tail light, in the rear. The rear light is required for the benefit of the Fire 
Department — to avoid accidents of rear end collision. To make driving at 
night safe, there are usually head lights which bum acetylene gas or elec- 

Electric lights are the most popular ; a storage battery supplies the elec- 
tric current; when the battery runs down it is recharged from an outside 
source, but if car is equipped with an electric generator, run from engine, 
the battery is kept charged by the generator. (This subject treated fur- 
ther on). 


Speedometers show the speed in miles per hour, and are operated by 
flexible shaft driven from the front wheel or transmission shaft. 

Odometers show the number of miles traveled, either on one trip or dur- 
ing the entire season. Speedometers and odometers are often built in one 
case, for the sake of compactness, one cable driving both. 

Orademeters show the per cent of grade the car is climbing. 

The horn for automobiles is sounded by pressing a rubber bulb, and the 
tube from the bulb to the horn is long enough to have the former at the 
drtver's seat, and the latter well forward. Another form of alarm is blown 
by the pressure of the exhaust from the engine, and it is sounded by pressing 
®^ a foot pedal. Exhaust whistles are the name of these horns, and the 
sound is very much like a locomotive whistle. 

The electric horn is the most popular. It will be explained farther on. 

Bumpers are placed in front of the car and sometimes in the rear. They 
Protect the radiator and lamps and are well worth the investment (see fig. 
10 Page 26). 

Wheel Base, Tread. 

The wheel base of an automobile is the distance (in inches) between the 
'"^^^ axles and the front axles. The long wheel base rides easier than a short 
^'^^el base. The frame must be sufficiently stiflf, however, to prevent sagging 
'^oxxx the weight on same. The wheel bases vary from 80 inches on runabouts, 
to I44 inches on larger cars. 

The tread (also called track) is the distance the two wheels are apart 
?^^*^iired parallel with the axle. The standard tread is 56 inches, measured 
ironx center to center. 

The treads of wagons and carriages vary in different parts of the country. 
^ ^He Southern states it is 60 inches, in the West 48, and most of the other 
parts of the country 56 inches. Small, light cars are sometimes made with a 
^^^ller tread than 56 inches, but it is exceptional. 

The clearance is the distance from the lowest point of the car to the road. 
*^^^ rough roads, a greater clearance is required than for smooth roads, as 
ft high place in the road would strike parts of the machinery that hung too 
low. The front axle, which is solid and heavy, is usually curved down in the 

c^ttter, so that it will be the first part of the car to strike a high place, thereby 

protecting the delicate parts behind it. 




DRIVE: Chain: Propeller or Shaft Drive. Worm Gear Drive. 
Radius Rods. Torsion Rods. Drive Reduction. 

The power from the engine is transmitted through the transmission; 
and is applied to the propelling of the car by those parts called the drive. 

There are three types of drive; one the double chain drive, requiring a 
dead rear axle, and the other the single chain drive (seldom used), and the 
shaft or propeller shaft drive, which requires a live rear axle, (see chart 13.) 

♦Double Chain Drive — see chart 11. 

The double chain drive is seldom used on pleasure cars, but is used quite 
extensively on trucks, t Trucks use chains, because trucks carry heavy loads 
and usually have solid dead axles. 

When, as is usual in cars of this type of drive, the engine is in front, the 
crank shaft is parallel to the sides of the car, and therefore at right angles to 
the rear axle. The power developed at the crank shaft must therefore be 
turned at right angles in order to apply it to the wheels. (See fig. 1, chart 
13.) This is done by means of bevel gears, which are in the transmission case. 

The power is transmitted from the crank shaft of the engine to the square 
shaft of the change speed gear by gears, as explained farther on. The square 
shaft carries a bevel gear that meshes with another bevel gear carried on the 
jack shaft (see fig. 1). 

The jack shaft passes across the car, running in bearings in the gear case 
and on the frame. It is held so rigidly that while it is free to revolve, its bevel 
gear is always in correct relation to the bevel gear on the square shaft of the 

The jack shaft is in two sections, between the inner ends of which the dif- 
ferential is placed, the differential, of course, being in a housing to side of 
the bevel gear that drives the jack shaft. 

At each end of the jack shaft, outside of the frame, is a sprocket which 
is in line with a corresponding sprocket on the rear wheel of that side (see 
fig. 2, chart 13). Over each pair of sprockets passes a chain that transmits 
the revolutions of the jack shaft to the wheels which run loose on the ends 
of the dead axle. 

The chain most commonly used for automobiles is called a roller chain. 
It consists of side pieces in pairs, each pair being secured to the adjoining 
pairs by rivets passing from side to side. On these rivets are steel rollers 
which revolve as they touch the sprockets. These rollers fit the space between 
the teeth of the sprockets, and as the chain bends around the sprockets the 
rollers are stationary, while the rivets turn inside of them. 

To give the best service, chain must run true ; that is, the sprockets over 
which they run must be in line, the links of the chain must fit the teeth, and 
the sprockets must be exactly circular. If the sprockets are out of line, the 
chain will be forced to bend sideways. If the links do not fit the teeth, there 
will be a grinding that will cause rapid wear, and there will be danger of the 

*For care and adjusting of chains, see instruction on trucks; also refer to this rabjeet on 
doable chain drive. 

tThe modem type of truck uses the worm gear drive. 



ehaiM jumping off. If the sprockets are not exactly circular, during one part 
of the revolution the chain will be slack, and during the other part will be 
drawn tight, stretching it. 

The double chain drive has advantages on heavy cars. By its use the 
weight of the car is carried by a solid or ''dead" axle, which is lighter than 
a divided **live" axle of the same strength can be. If a solid axle is bent, 
it can be straightened easily, while it requires an expert mechanic to straighten 
a bent live axle. 

The disadvantages of a double chain drive are the difficulty of properly 
lubricating the chains-, their rapid wear in consequence, and the liability of 
chains to stretch and jump off the sprockets. 

The worm gear drive for trucks with substantial axles of the 
type are now considered superior to the double chain drive. 


Single Chain Drive— see chart 11. 

This type of drive is now seldom used, and was formerly used only for 
cars with engines of small power, in which the engine is usually horizontal,, 
with the crank shaft lying across the car and parallel to the rear axle. 

A planetary change speed gear or transmission is usually used in a car 
of this type, and its sprocket is in line with the sprocket mounted on the 
differential on the **live'' rear axle (see chart 11 — also fig. 5, page 47). 


Clutch Peda] 


?^ ittodcm method for drlTtng the rear aade is by means of s propeller type of drive shaft with m 
J^^el dririog pinion and bevel driven gear on differential on rear axle. 
^'Bercial cars with shaft drive instead of double chain drive often use the worm drive, see page 21. 

^Propeller or Shaft Drive — see chart 11. 

Xn this type, a shaft connects with the square main shaft of the differential 
fr^ is extended to the rear axle, where it ends with a small bevel gear called 


^^e drive bevel pinion. 

.. Ihis driving pinion meshes with a bevel gear on the differential 
jp*t is mounted between the inner ends of the two parts of the live rear axle, 
caii^^ the axle drive bevel gear. 

. . ^the propeller or driving shaft, always has one, and often two, universal 
jomt:^ in between the gear box and drive pinion on rear end, so that the mov- 
^ ^f the rear end as the axle receives the jolts of a rough road does not 
raefji; i^ driving. 

*rhe bevel gears are contained within a casing or housing that supports 
^^ bearings for the parts of the axle, and also the end of the driving shaft, 
«o Xhai the bevels are held in the ^ame relation to each other, regardless of 
the moving of the axle. 





ifiOmB B^ 



^0cif smrr 








Fig. 1. 


Fiff. 2. 


( ) 








TOftS/OM /iOD 

Fig. 3 

CHABT NO. 13 — Explaining the Radius Bod, Torque Ann or Torsion fiod and Jack Shift 



The advantages of this tjrpe of drive are that all of the moving parts are 
enclosed and protected from dust, and run in grease or oil, which means 
perfect lubrication. 

The disadvantages of a divided or split rear axle, are the difficulty of 
keeping the bevel gears in exactly the correct relation to each other, because 
of the bending or springing of the axle, and the troubles that may come from 

the general weakness of 
a live axle. (This trouble 
has now been overcome. 
During the early days it 
was a source of bother.) 


Bevel gears must be 
cut more accurately, and 
meshed more carefully, 
than spur gears. They 
are used principally for 
driving the rear axle (see 
page 32). 

To transmit power 
without more loss by fric- 
tion than can be helped, 
there must be as little 
play as possible without 
having the teeth bind. 

tThe setting of bevel- 
gears requires careful ad- 
justment, for if incor- 
rectly meshed they will 
be noisy, and will wear 

^H£W &LAfT5> 

B£ VIL p. MOW 




Note the different methods of driving. Bevel gears are 
used extensively on rear axle drive systems. Worm gears 
sre also used on rear axles. Helical gears, silent chains 
sre used extensively for magneto, electric starter and 
generator drives. Spur gears and the dog clutch are used 
in the gear box. 

i^The worm drive gears are fast becoming popular for rear axle drives, 
especially on commercial cars (see illustration above). 

The spiral bevel, which is often referred to as helical gear is similar to 
^e worm. The worm gear makes a wiping contact and the helical more of a 
filing contact (see page 35). The **skew'' gear is the same as the helical 
ffear. This type gear is also used to drive ignition systems, etc. 

Silent chains are used principally for driving generators, magnetos, cam 
®*Jafts, etc. (see index). 

Sprocket chains are used to drive the rear wheels in chain driven cars. 

_ '''Radius rods: are mostly used, on commercial cars using double 

^^ixi drive. They extend from a point along side of the frame in line with 

**^ jack shaft, thence to rear axle. Therefore they keep' the chain at the 

proj^ej. tension and the distance from sprocket to sprocket the same, no matter 

^ow- rough the road. A turn buckle is provided to adjust (see fig. 2, chart 13). 

^lany manufacturers however, have now discarded the radius rods entirely. 

^Also called "strut** or "distance** rods. 

tSee rear axles in repair subject and supplements, 
the "ordinary bevel" and the "spiral bevel** 

. -^ TBevel gears for final drive are of two types 
VOt^ejj referred to as the helical). 

^In principle the worm drive is a simple arrangement; the usual bevel gear and pinion are replaced 
"T ^ specially-shaped hollow helical-toothed gearwheel and worm, the latter engaging in the teeth of 
*** Gearwheel, the axles of the two shafts being at right angles. When accurately made, worm gears 
'h ^^^«f **^ smoothness and silence. The worm may engage either from above or below the gear- 

^^!J*l. The angle of the worm and gear may be as much as 45 degrees. Tlie worm (W) is made 

at tttrd steal and the wheel (B) of bronse. 


The Torque Arm. 
A torque arm (''torque*' means turning movement or twist) is used on 
shaft driven cars. It extends from the cross member near the transmission 
to the housing on the rear axle, (construction varies). 

A usual construc- 
tion is shown in illus- 
tration. Note the arm 
(N), extending from 
the rear axle housing 
to a spring arrange- 
ment or torque pillar 
^^^ attached to a cross 

2- ph>P7*ifrnnt^'"^^iag^^^^ll^^iHfc^^rs. // member, in line with 

c. tFowu i»c.'^s ^neofcp-^ ^^^^r>"" ^l ^^^fe tf the drive shaft (see 

F DiQereiitm brvcl ^t»r pituoui. / tfS_ * ^^^■^^^^'W lllUStratlOU (S-N). 

G. A*Je CA^iiig.. ^' ' ^f~^ ^ ■^*' ^ ' 

H. Ur^ke!ili«rj by pid^L 

AI Worru vihtri boding, ft. ktii ipnoi^ th^ki^. ^r r)*! 4-1* g HotCllKlSS 

N. Torque rod*. S. Torque pilUr. y" 7"^ ^ , 

drive the torque and 
drive is taken through the rear springs. The main leaf of each of these is 
made strong enough for this added duty, and the construction does away with 
torsion tubes, torque arms, and radius rods. On^many cars the propeller shaft 
housing is made very heavy and acts as the torque arm. 

If it were not for the torque arm, the revolving of the bevel gears would 
tend to revolve the rear axle housing, instead of revolving the axle shafts 
alone. While the construction of the rear axle would of course prevent this, 
there would be considerable play in the course of time, and the driving shaft 
might be strained and sprung out of line. The torque receives this strain, 
and protects the driving shaft. In other words it resists the torque of the 
rear axle when power or brakes are applied (see note on page 32). 

Drive Reduction. 

In all but racing cars, the speed of the crank shaft is reduced so that 
the road wheels turn once while the crank shaft revolves from three to four 
or four and one-half times with the high speed gear engaged. 

On cars with single chain drive, this is done by having the transmission sprocket 
^maUer than the axle sprocket. 

If the reduction is to be three to one, that is, if the crank shaft revolves three times 
to once of the axle, the axle sprocket will have three times the number of teeth that the 
transmission sprocket has. 

On shaft driven cars, the reduction is made at the axle drive gears. The gear on the 
axle is given as many more teeth than the pinion on the driving shaft as is neeessary 
for the reduction that is required. 

In the worm drive (see pages 32 and 35) the reduction is governed by the angularity 
of the teeth and not by the ratio. In other words the size of the worm could be ehanged 
Vithout its changing the speed. (The angularity of course would have to be the same in 
both cases.) 

To make the point clear as to just how the speed reduction is brought about in the 
worm drive, imagine the screw thread on a vise shaft which draws the jaws together. 
If that thread is coarse or has only a few to the inch, the jaws would move towards eaeh 
other rapidly and of course would take some power to move it; if, on the other hand 
there were quite a number of threads to the inch the jaws would move slower but it would 
take less power to exert the same pressure. 

The reduction on side chain cars is sometimes made at the bevel driving the jack, but 
usually at the sprockets. 

Bacing cars, or high powered touring cars for use over good roads, apply this redue- 
tion for the direct drive, but by the use of gears in the transmission may bring the speed 
of the wheels to the speed of the crank shaft, or even more. 

When the "gear ratio" of a car is spoken of, it is this reduction that is' meant. A 
car spoken of as having a "gear ratio of 3% to 1" is one in which the drive shaft 
makes 3% revolutions to one revolution of the road wheels on the high gear. 



^STEERING, SPRINGS, BRAKES: Principle of Steering. Springs 
and Brakes. 

The principle : Pulling on one of the reins swings the horse to that side, 
in steering a wagon. The shaft or pole is attached to the axle, and the axle 
is pivoted to the king pin, all swing with the horse. 

If you go straight ahead, the front and rear wheels of any vehicle move 
in straight lines. To make a turn to one side or the other, the front wheels 
are swung so that they are at an angle with the rear wheels. 

Whenever the front wheels stand at an angle with the rear wheels, the 
vehicle will turn, and it will continue to turn until the front wheels are swung 
back to a straight line again. 

In a horse-drawn vehicle, the front wheels are square with the axle, for 
wheels and axle swing together. (See fig. 1, chart 14.) 

In an automobile, the front axle does not swing, but each wheel swings 
on a pivot at the end of the axle. 

It would not be practical to steer an automobile as a horse-drawn vehicle 
is steered, for the axle would have to be very heavy to support the weight, 
and besides, it would be so hard to swing it that steering would be difficult. 
Another reason is that the body would have to be raised up high so the wheels 
could go under it in making a short turn. 

A fixed front axle is always used on automobiles. The pivots on which 
the front wheels swing must be as close to the hubs of the wheels as possible, 
for the closer they are the less leverage there will be to overcome, and the 
easier it will be to steer, also less liable to break. 

When a wagon or automobile turns a corner, it moves in the arc of a 

In a horse-drawn vehicle, the front axle, because it swings on the king 
pin, always points to the center of the circle (see fig. 1.) Notice that both 
wheels and the axle are perpendicular to the same radius of the circle in 
Sg. 1. 

The front axle of an automobile is fixed and cannot turn, and therefore 
^^y its pivoted ends point to the center of the circle (fig. 2.) Notice in fig. 
^1 tJiat the axle does not move, but that each wheel moves. 

When running straight ahead, the front wheels of an automobile are 
^vi^are with the axle. When turning, the front wheels are not square with 
^^ axle, but at an angle with it. 

Because each wheel is square with its axle end, and both axle ends point 
^ "tie center of the circle, each wheel is square, or perpendicular to, a radius 
^' ^tiie circle. If both were perpendicular to the same radius, which they are 
^^^, the wheels would be parallel with each other. 

Thus while the front wheels of a horse-drawn vehicle are always parallel 
^^ each other, the front wheels of an automobile turning a comer are not 
P^^^llel to each other on the same radius. 

*See pages 684 to 691 for "adjusting brake" and pages 691 to 693, "adjusting steering." 

«Mw. Sometimes the driver will notice he can turn his fron.t wheels farther to one side than the other. 

^^^ is dne to two causes: (1) the steering knuckle arms are not properly lined up; (2) the tire 

^ 'Wheel may strike the steering knuckle thrust arm. 

• It is also noticeable that an automobile has a tendency to travel to the curb when running on the 

**^% of atr ee ta . This is due to the oval surface of street or if wheels are "cambered" too much, see 

**8«e also, page 601. 





Showing how a Front Axle of a Showing how the Front Wheels of 

horse-drawn vehicle gives the direc- an automobile give the direction 

tion a horse-drawn vehicle runs. the car runs. 

Front Axle. 

1— Front Axle 

2— Steering Knuckle 

3— Steering Knuckle 

5—. Rod 

t>— Steering Arm 
. Thrust Bod 
7— Knuckle Thrust 


Steering and Oonnec- 

81~Steering Device 

63— Steering Column 
64— Steering Wheel 
65— Steering Arm 
57— Spark Lever 
68— Throttle Lever 
71— Spark Lever, bell 
crank connecting 
through bevel to 
spark lever on 
72— Throttle Lever, 
bell crank con- 
nee ting with 
throttle lever thru 
a shaft, thru 
steering column, 
with t h r o 1 1 le 
lever. 68 
W— Worm Wheel 
S— Sector. 

Sj)ark Lever (67) connects by a rod (which runs through the hollow steering post) 
id operates through bevel gears the Bell Crank (71), which in turn operates the timer 
I the engine or contact box on magneto, and advances or retards the spark in 
linders of engine. 

Throttle Lever (68) connects by a rod, through bevel gears, and operates the bdl 
ank (72). which in turn is connected by a rod with the throttle valve on the carbure- 
r, and controls the speed of the engine by oponing and closing a valve which 
Imits or cuts off the gas supply. 

3ART NO. 14^Ezplanation of Steering. Steering Gear, Parts 
Spark and Throttle Lever System on the Steering Device. 

and Oonneetlona. 


The steering mechanism must be so arranged that the front wheels are 
parallel when the ear is running straight ahead, but stand at an angle with 
each other when turning a corner. 

Each of the pivoted axle ends (2), which are called steering knuckles, 
has a steering arm (3 and 4) projecting from it. 

The ends of these two arms are connected by a rod called a drag link or 
tie rod (see fig. 5). When the drag link is moved endways, both wheels 
move with it. 

The two steering arms are not parallel, but incline a little toward each 
other. If they were parallel, the two wheels would be parallel, no matter how 
the drag link was moved. As they are not parallel, moving the drag link 
moves one of the wheels through a greater angle than the other, depending on 
the direction the drag link is moved. 

The old style of steering arrangement was a lever and rod running from 
the driver's seat to the steering knuckle. This old style arrangement would 
reverse and was unreliable. In striking stones or ruts in the road the wheels 
could be thrown from side to side, and the driver would be obliged to grasp 
the steering lever firmly to keep the car straight. 

A bad place in the road might throw the handle out of his hand. While 
this is good enough for a light slow speed runabout or electric vehicle, it 
would be very serious with a large, heavy automobile. 

A device must be used that will swing the front wheels when the steering 
wheel is turned, but that will keep the front wheels steady, and prevent their 
moving the steering wheel. 

This is called an ^irreversible steering gear, and while it is made in many 
ways, the chief types are the worm-and-sector, and the screw-and-nut or 
worm-and-nut, all shown in chart 14. 

*'The worm-and-sector type consists of a worm (w), .which is attached 
to the lower end of the rod moved by the steering wheel (64). Meshing with 
the worm is a sector wheel (s), so that turning the steering wheel turns the 
>^onn, and moves the sector wheel. 

Attached to the sector is an arm (65), which is connected to the steering 
knuckle by the connecting arm or rod (6). The end of arm (65) and arm (7) 
we ball shaped, and fit in a socket on the end of rod (6) so that the fit is 
always tight, whatever the angle between the arm and the connecting rod 
"jay be. The socket is often movable, with strong springs on each side to hold 
"le parts together, and to take up some of the shocks of the road. 

The worm and sector are contained inside a metal case to protect them 
"om dust, and to hold the grease in which they are packed. 

**The worm-and-nut type steering gear shown in chart 14, has a nut 
through which a worm passes. Instead of a ** sector" the nut is used, 
^e worm is fastened to steering rod. Turning the steering wheel moves the 
oot up and down. 

One arm of a lever fits in a groove on the outside of the nut, and the 
other end is connected to the steering knuckle by a connecting rod. Steering 
gears are usually built so that wear can be taken up. 

The breaking of any part of the steering connections is more likely to 
cause a wreck than the breaking of any other part of the car, and must be 
watched carefully. The parts must be kept tight enough to prevent play, but 
i&ust not be so tight as to make steering hard. All parts must be kept lubri- 
cated, and the connecting rod, tie rod and knuckle joints are usually packed 
^ grease and protected from dust by leather pockets that buckle over them. 

*A Hetring gear ia smid to b« irrererslble when an ordinary road wheel impact will be insufficient 
^ tarn the steering wheel. This is simply a question of reduction between the steering worm and 
C*ar, the greater the redaction, the less reversible the system and likewise the slower the motion 
af steering the road wheels in relation to the movement of the steering gear. Therefore a heavy 
<ar will be normally less reversible than the steering Kear on a lifhter car. **8ee also, page 691. 


Hajr elKpilo r«&r sprtaf 
«iic^or«d cfi pint oa «m 

3. A 

FIf. 8» A hilf-elliptic spring for front. Tig, ^. ., 
•prlng for th« rear. Fig, 2. Throe biilf-elliptic «prinjf 
very pnpuUr type of spriof for retr iUxpensioD. 

Fig, 10. Bumpsra hrt pkccd on tho front and 
quit* oitea on th« roar of tbo car to protect the 
rftd]»tor iiad lamps und rear of ear. See also, puge 
730, 514 


Fig. 9. Friction type of shock abaorbvr conaisti 
of A single arm, A. sod a doubls arm, B, ^riction- 
allj joined by bolt, 0, luid adjuAtlQg nut, H. Arm 
A works beltreen ibe two memboni of arm B. giv- 
ing a ttraigbt op -and- down movemont, and tbe arm 
A being made of tpring tteel altowa for any side- 
ftvfay. The arm A carries a flanged cover, D, form- 
ing a cup-like space on each side. lo these tnaces 
•re placed the friction platea, which are telf*ltibri' 
ealinir nnd highly impervious to wear. By screwing 
•nfflclcntty on adjusting out. H» any desired degree 
of friction may be obtained, 

Adjustiseiit dial, F, and indicator, G. provide 
in^<..,w i.f « enuring the correct tension for the car* 
A pensating sprine. E, takes up any little 

\i itically. keeping the friction uniform 

afu . ...._ „,^justment has been made. 

The arms A and B are joined to the frame and 
ftzla by two ffictionat joint*, vhich also can be ri 
rtgulated, Abo^e type I* the * 'Hartford.'* •#♦ ' 
page 732 for the ** Conn e<rti cut.'* 

half-elliptic spring for ttie r«ar. Fig. 1, A full eUiptie 
I for the rear. The cantilever spring page 27 is a 

Fig. 7. Atr irprlng or plunger type shock absorber 
consists of an air chamber made up of two lectioDa, 

one of which 
tcteecopes into 
the other. The 
outer eeetion 
is attached to 
a bracket on 
the frame of 
the cur (A). 
The inn«r sec- 
tion is attach- 
ed to one end 
of one of the 
springs, (B). 

The cham- 
ber la partly 
filled with oU« 
through the 
filling -plug 
bole unditr 
the cap (C). 
J T h e milDg- 
plug is flttod 
with an ordin- 
ary Schmder 
tire type of air valvo through whk-b the chamber 
may be cbarKcd with air at any desired pressure^ 
by means of au ordinary tire pomp. 

Th« oil In the chamber seals the packings of th« 
teloBCopiDg joint and prevents the air from leak* 
ing out. 

The tDftchanlsm inaldo tho 
chamber is a tmaU oil pump 
wbich is worked automatically 
by the up and down flow of oil 
past the flat piston (D). when- 
ever the air spring Is compress- 
ed or extended. A trifling 
amount of oil which is always 
passing by the packlnjirs when 
in motion keeps them thorough- 
ly lubricated The surplus drama 
into a collecting pocket, and the 
auLomatic oil pump delivers it 
back into the cushion chamber. 

The oil passage surrounding 
the piston D is purposely re- 
st rieterl in order to retard tho 
quick reaction of the spring, 
and thus prevent the disagrea* 
able and dangerous catapult «£> 
feet that is so apt to throw 
paasengers from thetr seats 
when the car is patsing over 
"thank - you -mft 'ami,** ear 
tracks or other road obstruc- 

All of the time that the sprlsf 

uiTiM^ Is in action, air is being drami 

"**^ in through filtering matorial 1&_ 

B the "breather" E. and blov 

out through suitable pasaag 

in such a way as to keo^ 

telescoping joint free of dtui 
and dirt. (Westinghouse.) 


OHABT NO. 15 — SprinjEB. SIiocIe Absorbers. 




^Springs — see chart 15. 

All yehicles intended to move at more than a very slow speed must be 
provided with springs. Springs not only protect the occupants from the vibra- 
tions of a rough road, but also keep the machinery from being shaken to pieces. 

The size and strength of the springs depend on the weight of the vehicle. 
Springs that are too weak will not give sufficient protection and if they are 
too strong they will not have enough resiliency. 

Types of springs in general use are: Full elliptic, three-quarter elliptic, 
half elliptic and cantilever. 

Tlie fuU-eUlptic was formerly used od a great many 
cars for the rear, as per fig. 1. In some instances it was 
used in front. 

Other types of rear spring suspension are shown in 
figs. 1, 2 and 3, also the cantilever, fig. 4. 

The cantilever spring system (fig. 4) is probably the 
most popular present day practice. The illustration 
shows how it compares with the ordinary half-elliptio 
principle shown in fig. 3. 

In the cantilever spring the forward end is shackeled 
and the axle attached to the rear end. The center of the 
spring is attached to a trunion or bearing on the frame. 
Thus the spring has a certain amount of movement about 
its center. One good feature of this form of spring is 
that it reduces the unsprung weight of axle. The shaded 
parts of the respective springs show the comparative 
amount of unsprung weight. In the cantilever form of 
spring the heaviest part of it is supported by the frame. 

The half-elliptic spring (upper fig. 8) is used to a 
great extent for the front. 

^Breakage of a spring means breakage of one or more 
of the leaves. Breakage almost always occurs in the ex- 
pansion that follows a heavy compression, and not dur- 
ing the compression. In other wordsy it is the rebound 
that breaks the spring. 

Because the leaves slide on each other, they wiH 
wear and squeak if not properly lubricated. 

To lubricate between the leaves it is necessary to 

relieve them of the weight they carry. This may be 

done by jacking up the body, or taking the springs apart, 

and spreading heavy grease or graphite on the leaves. 

_- ^. ^ „4_^, This is quite a job and is seldom done (also see index 

Th« thr««-qiuirter •lliptie re«r in,a.,i-«fi^^ ^Jr.^ »n 

•priar A type leldom lued. ''lubricating springs.'') 

Shock Absorbers — see chart 15. 

Ab breakage will come during a rebound, devices called shock or jolt 
absorbers are attached to the springs to check their up movement, also to 
prevent jolting on rough roads. 

There are two types of shock absorbers in general use ; the friction type 
and the air or plunger type. 

Hm friction type is shown in fig. 9. All these movable frictional parts offer a con- 
•taat reoetanee to the vibration of the spring both ways, and it is easy to see that when 
fke wheel strikes an obstruction, the arms come together, but instead of the flying back, 
as does the free spring, it is retarded by the friction and moves gradually to its normal 
position^ since tiie frietion is always the same, while the tension of the spring diminishes 
as it approaches its normal poedtion. See also, page 732. 

ns air or plimgsr typo is shown in fig. 7 chart 15. There are other types of plunger 
type shock absorbers, bat the two mentioned are most popular. 

*8m rtpeir mbj^et for repairing springs. 



/tea, mi^BLB ACrmO SAAfO 



CfiABT NO. JU — Brakes and Brake Syatema. Explanation of tha "Bunning'* or Foot Brake and 

the ''Emergency" or Hind Brake. The band brake oentlly operates the internal brake InaMa af 

iAe remr brake drums or the brake on trautmisaion shsft. The foot brake operates the atemml 

^rsko oa Ihe outnif/e of rrar dniins. Thi* m nifuli^rn prartico. 


^Brakes — see chart 16. 

An automobile is equipped with brakes, usually on drums on the rear 
wheels, so that its motion may be checked or stopped when running or so 
that it may be held on the side of a hill. 

In a horse-drawn vehicle with steel tires, the brake shoes press directly 
on the tires, but as this would quickly ruin rubber tires, brakes for automo- 
biles are of other types. 

Because of the weight of an automobile, its brakes must be powerful in 
order that it may be stopped suddenly when necessary. 

Practically all automobiles are fitted with two sets of brakes, called the 
running service or foot brake and the emergency or hand brake. 

"""The foot brake is applied by pressing on a foot pedal (16) and is the 
one most in use because of its convenience, and because it is used most when 
ninning. The foot brake is also called the service brake. 

The usual method of connecting the running, service or foot brake is by 
a contracting band on the outside of the brake drum on rear wheel hubs called 
the external contracting band brake. 

The emergency or hand brake is usually applied by a lever (17) at the 
side (or center) of the driver's seat, so placed that he may apply his whole 
force to it. The emergency brake is seldom used while running. It is usually 
applied when the car is left standing, in order to keep the car from rolling 
down an incline. It connects in almost every instance with the internal ex- 
panding brake inside of the brake drum on rear wheel hubs, but occasionally 
will be found connected by a contracting band over a drum mounted on the 
Diain transmission shaft. 

The foot brake pedal is the right pedal on most all cars, see ''operating 
a car." 

Types of Brakes. 

Therefore summing up the types of brakes we might say there are but 
two distinct types in general use; the external contracting and the internal 
expanding type. 

The external band brake is a flexible steel band faced with an asbestos 
composition — called Raybestos or Multibestos. 

Setting the brake causes friction between the brake drum and the lin- 
ings, hence the use of asbestos composition. 

Band brakes are of two kinds: Single acting and double acting, the 
latter being an improvement over the former. 

The single acting band brake (fig. 1, chart 16) only binds when the drum 
is revolving in one direction, having very little grip when the drum is re- 
irolving in the same direction in which the band is being pulled. This form 
is going out of use for automobiles, for it cannot be depended on to hold the 
car from running down hill backward. 

The double acting band brake (fig. 2), is taking its place, for it holds 
with the drum revolving in either direction. In this form, both ends of the 
brake are attached to the lever or pedal, and so arranged that while one end 
is being pulled in one direction, the other end is being pulled in the opposite 
direction. This binds on the drum so tightly that it may be depended on to 
hold the car in any position. 

*Th0 nmainf braks it now known ai ths "foot brake." The emergency brake U now properly 
criM tiie ••kAAd brake." 

8m pttc* Mft for "adjnatinf of brakea." 



The brake shoe is a band that may either be drawn around the outside 
of the drum, called the external band brake, or expanded within it so that 
it bears against the inside wall of the drum, called the internal expanding 
brake. Sometimes the internal brake is made of metal. 

The external type of brake is usually of the double acting band brake 
type, and is always placed on the outside of the brake drum attached to hub 
of rear wheels. 

The internal expanding brake acts on 
the inside of drum (IB, fig. 7) and may be a 
metal shoe or metal faced with asbestos 
composition, but more frequently a band 
faced with an asbestos friction composition. 

The internal band brake formerly con- 
sisted of two shoes of metal, but the modem 
form is shown in fig. 4, chart 16. When the 
lever (B) is raised the wedge (C) forces the 
internal brake against the inside of the drum. 
This brake shoe is lined with Raybestos or 
some similar material. 

A combination of internal expanding 
and external contracting brakes are shown 
in fig. 4, chart 16. Lever (A) operates the 
external brake and lever (B) the internal 
brake. (See also fig. 7 this page, and page 


Fig. 7. — ^A combination of an Internal 
•xpandlng and external contracting brake 
lyitem on brake drum of rear wheel hub. 
OB ii the outer or external and IB is the 
inner or internal. B ii the hand brake 
rod operating the internal brake. H, foot 
brake rod operating external brake. Ad- 
Juitment of external brake is made at F. 
Q and 0. Adjustment of Internal or hand 
brake la at A. It is turned up or lowered 
io at to have 1-64 inch clearance between 
brake drum and brake. (See page 691 
for * 'adjusting brakes" for further in- 

Brake Connections. 
There are two methods usually employed for the hand brake; (1) by con- 
necting hand l^ver with the brake on transmission shaft; (2) by connecting 
with ti^e internal expanding brake inside of drums on the rear hubs. This 

latter method being the one in general use. 
The foot brake on most all cars connects 
with the external band brake on rear brake 
drums. It is used most and requires more 

Brake Equalizers. 
When the foot brake pedal or hand 
brake lever is applied, the pull should be the 
the same on each brake on each wheel. If one 
brake rod is longer than the other the brake 
effect is not equal on both wheels, and this 
has a tendency to make the car skid. 

To overcome this, a brake eqnaliier is 
used, the principle of which is shown in figs. 
5 and 6, chart 16, and page 204. This is a 
rather crude illustration in chart 16, but it clearly explains the principle. In 
chart 100 the idea is more clearly explained. The brake equalizer, however, 
has been greatly improved as shown in illustration, fig. 8. Also page 32. In- 
stead of an equalizer, the rods (R) are placed in bearings and the rod (P) 
connects with foot brake and rod (H) with the hand brake. 

If a brake squeaks, it is an indication that it is dirty and needs cleaning 
The dirt clogs the pores in the surface of the lining and glazes it over. Qaso- 
line or, better, kerosene will remove the dirt. The wheel should be removed 
and the linings cleaned with a stiff brush, such as a tooth or nail brush. 

Fig. 8. — Note modern method of con- 
necting the two brakes in rear. 




BEARINGS: Front Axles. Rear Axles. The Differential: 
principle and application; the bevel and spur gear. Bearings: 
ball and roller. 

Front Axles. 

The front axle of a modern car carries most of the weight of the engine, 
and most at the same time withstand the shocks and jars that it receiveB 
through the steering wheels ; it must therefore be strong and stiff. 

Front axles are of two ^es: tabular 
and solid (figs. 1 and 2). Formerly 
axles were made of heavy steel tabet» 
but steel drop forgings with a cross-see- 
tion of the form of the letter I, is con- 
sidered to give better results. 

The center of the axle is usually bent 
down, so that it is the lowest point of 
the car except the wheels; this is done 
in order to protect the mechanism from 
being struck by high spots in the road. 
A rock or stump standing up high 
enough to hit the fly wheel, will first 

itrike the axle, which is strong enoupch to withstand a blow that could easily 

dimage the engine. 

The steering spindles are that part of the front axle on which the front 
wiieeb revolve and are made of nickel steel, heat treated. The steering 
spindles are sometimes fitted with either roller or ball bearings. The steering 
tanudde is that part which fits into the yoke of the axle. The steering arm 
(66) of the device (page 24) connects with the steering knuckle thrust arm 
(7), and movement of steering wheel, then guides the direction of the wheels. 

♦Bear Axles. 
There are two types of rear axles; the dead axle and the live axle. 

Dead axles are stationary, with the wheels running free on the end of 
^e, and are usually made as shown in fig. 3. The wheels are usually revolved 
l>7diain and sprocket (see charts 11 and 13), and there is no provision in axle 
itaeU for driving wheels. 

Live rear axles is the name given to axles that revolve with the wheels, 
and are known as plain live axle, semi-floating axle, three-quarter floating 
axle, fnll-floating axle. 

A live axle on any type is made in two sections, the differential be- 
iog placed between its inner ends, this makes it necessary to support the axle 
parts in a strong housing and to brace it, in order that the parts of the axle 
do not sag or get out of line. 

The axle is contained in a housing which is a metal cover entirely sur- 
ronnding it; the differential gear, which is in a smaller housing of its own, 
being also inside of the axle housing. The housing extends to the wheels, 

*B— pagM 644 to 646 for mako of axloi uiod on loading oari and pago 66f for 

'roar axlo 




Eir«nul BfAkr 

J a If nut 


All* Mi»Diiat 

Din«r#»(ial Beirini 

Constxuctlon of a Bear Azle — (Harmon). 
lUustrating rear axle complete with bevel driving gear (E). Differential (bevel pinion 
type). The actual driving axles do not support any dead weight. The road wheels run 
on ball bearings (I) carried on the outer sleeve or casing of the alle. The details are 
aa follows: — (A) propeller shaft connection. (B) driving pinion shaft. (C) ball thrust 
bearings. (D) bevel driving pinion. (E) large bevel. (F) differential gear. (G) half 
of driving axle. (H) tubular outer casing or sleeve. (I) ball bearing for wheels. (J) 
driving ends of axle (squared or keyed). (K) roller bearings in differential case. (L) 
drum of internal and external brake. (M) hub of detachable wire wheel. (N) casing 
enclosing bevel gear and differential. 

Note — The power is transmitted from driving bevel (D) to large gear (E) — this being bolted 
to the case of the differential (F) — thence by the inside pinions to each half of driving axle. It Is 
usual to * 'anchor" the outer casing enclosing the differential gear to the chassis by means of torquo 
or hound rods bolted to the upper and loiwer points of the gearcase which counteract the tendeney 
for the whole casing to twist round from the reaction of the driving effort. On some cart the raar 
springs are made to serve as torque rods. 

Fig. 3 — A single chain driven live rear axle 
now obsolete. 

Fj^. 4 — Overtype 
wprm drjv$ rear 
axle with inipf^e- 
tloa cover plate re- 
nioveU eJcpo»lng the 

tfuLfm Mt0im 

Fig. 2 — Full floating live rear axle with roller bearings. 

OHABT NO. 17— Bear Axles. 



and is enlarged at those points to take the ball or roller bearings. These 
bearings ran between the axle and the inner side of the housing, or as shown 
in figs. 5, 6 and 7. 

There are also bearings at the inner ends of the two parts of the axle, 
close to the differential. The axle housing of this type must be heavy, as it 
anpports the weight of the car. 

Types of Bear Axles Explained. 

Plain live axles: have shafts supported directly in the bearings at center 
and at ends, carrying a differential and road wheels. This type is now prac- 
tically extinct. 

*Fiill floating type of rear axle: the weight is taken from the axle, and 
mpported on the housing through which the axle passes (fig. ^). 

The hubs of the wheels are outside of the housing, and the bearings are 
between the inside of the hub and the outside of the housing (fig. 5). 

The axle passes through the housing, and the ends that project are square; 
oyer these square ends fit caps that screw or are bolted to the outside of the 
hub. Thus when the axle revolves, the caps transmit the movement to the 
wheels. As the wheels run on the housing, the housing supports the weight, 
the axle serving only to turn the wheels. By removing the caps, the parts 
of the axle may be drawn out without removing the wheels, which hold up 
the car whether or not the axle is in place. 

By jacking up the car to take the weight from the wheels, they may 
be drawn off the housing. The live axle is not continuous, but is dividad in 
the center (see chart 18). 

In the "geml-floatbi«" type, more properly 
called the ''fixed hub*' type (see figure 6), the driv- 
ing shafts turn freely within the housing. At their 
outer ends they are fixed in the hubs of the wheels 
and earry the bending stresses as weU as the torque. 
The hub of wheel in fig. 6 is fitted to shaft (P) with 
Woodruff keys and nut (N) which serve to secure 
wheel to shaft. Hub cap is merely a protection to 
end of hub. 

In the "three quarter fioating" (figure 7) or 
better the ''fianged shaft'' type, the housing ex- 
tends into the hubs of the wheels as in the ''full 
floating" type, but the ends of the driving shafts 
are connected rigidly by flanges with the wheels so 
that the shafts take almost all the bending stresses 
and all the torque. In the flanged shaft axle, espe- 
cially when only one bearing is used under the cen- 
ter of the wheel, the stresses are quite similar to 
those in the fixed hub type. 

In the "fuU floating*' type of axle (figure 5) 
all the bending stress due to static force and skid- 
ding force is carried by the housing. The driving 
shafts turn freely within the housing and bear only 
the "torque" or stress of turning the wheels. The 
shafts are said to float within the housing. 

In the full floating axle the shafts can be more 
easily removed for repairs. This is an advantage. 
It is necessary to make the full floating somewhat 
heavier than the fixed hub type for the same capacity. 

*8m Alto index for "axlea, full floating;" and ''removing axles." aee pages 669 and 932. 

Ib th« fan flostlBf Azle the entire differential can be removed by unscrewing 4 bolts (aft«r 
««vcr pUte U removed). In the % floating, two gears must be removed first, before differential 
•u be taken oat. and in the temi-floating. the entire housing must be removed from car, see page 669. 



ric. f Ty*t-9mmUT /lMn'«( «r fUmtfJ Sk^l 




Every part of the car that moves with a 
rotary, sliding or other motion is supported 
in bearings, which together with proper 
lubrication reduce wear and friction. 

There are three different types of bear- 
ings in general use; the plain, roller and 
baU bearings. 

Bearings are called upon to do two kinds 
of work; to take a radial load or a tbmst 
load or a combination of both. 

A radial load is load or pressure perpen- 
dicular to the shaft supporting the load. 
For instance, the wheel bearings of an 
automobile, when running on a pyfectly 
level road are subject to radial loads. 

Thmst load is a load or pressure parallel 
to or in direction of the shaft. When the 
automobile strikes a curve a thrust load is 
imposed on the bearings in the wheels — 
that is, to the side or endwise. 

fWe might iUiutrate tb0 relation between thmst 
Mid ra41u loada In this way: A man could be 
eoniidered ai being subjected to pure radial load 
when walking on an absolutely level surface, flg. 
8. but when this man walks alons a hillside, with- 
oai either ascending or descending the hill, as 
Illustrated in flg. 9, he is subjected to a combina- 
tion of radial and thrust load ; the thrust load hav- 
ing a tendency to push him down the hill. 

If a atralght roller were called upon to take a 
thrust load as well as a radial load, it might be 
compared to the man in flg. 10, he would need 
a crutch to prevent his toppling over. Therefore 
a ball thrust bearing (flg. 7) would be necessary 
at end of the straight roller bearing, per flg. 12. 

Plain bearings are usually on the main 
crank shaft, cam shaft and connecting rods 
of an engine and take a radial load. 

Plain bearings can also be designed to take 
thrust loads. 

BoUer bearings 
are used in the 
wheels, rear axle, 
transmission and 
other places and 
when stralghti as 
per fig. 2, they 
can only take a radial load. The roller 
itself runs over an inner race and inside of 
an outer race, case hardened. 

When a roUer is tapered, it runs over a 
cone type hardened race (fig. 1), and inside 
of a outer race, arranged as 
per fig. 11 and pa^e 687. This 
type of roller bearing will take 
a radial and a thrust load 
without the use of a separate 
thrust bearing. 

The groove in the race and roller, fig. 11, 
take the thrust load as well as the con«t 
shape of race. 

A straight roller bearing, to take a thrust 
load as well as a radial load, would require 
a separate thrust bearing, fig. 12 and flg. 9, 
page 676. 

Ball bearings are also used on the wheels, 
roar axle, transmission and other places. 

They are di- 
vided into 
three g e n- 
end classes; 
cap and 
cona^ anno- 
1 a r and 

The cup and cone bearing is shown in fig. 
4, and is used on many cars in the front 
wheels. This type of bearing is used ex- 
tensively on bicycles. It is designed for 
radial loads but is capable of wit&tanding 
considerable thrust also. It is adjustable. 

L^i^i] S^ bearing is a bear- 
1^^^^ r^'Ti ^°fi> with an inner 
and outer race, 
which is grooved 
and hardened. They 
. ^^^^^ are not adjustable. 

LJ IV ii Jl P ji "single row" of 
9*^ HBHI^aii^^,^ balls, per fig. 8 and 
5, or " double row, " 
&g, 6. The single row takes a radial load. 
The races of the double row are so shaped, 
that it will withstand considerable thrust as 
well as a radial load. It is used where 
space would not permit the use of a separ- 
ate radial and thrust bearing. 

An example of where a bearing of this txp* it 
used is shown in flg. 4, page 82. Note the double 
row bearing is shown on the rear end of the 
worm taking the thrust (which is eoniideiable). 
and also takes a radial load. 

The ball thmst bearing is shown in flg. 7. 
This bearing can be used only where the 
load or stress is strictly a thmst or end to 
end load. 

This type is often used in clutches and it ex- 
tensively used on the propeller shaft driying the 
propellers of motor boats. 

The two parts the balls touch ara called 
races. The one or two balls at the lower aide 
support the entire weight and must be strong 
enough to hold up without being crushed. 
In automobiles, the balls are large and run 
in size up to 1 in. di. hardened and polished. 

Sometimes balls wear flat or crack; if so 
a click will be heard and must be replaced 
with perfect balls at once. 

*See page 681 "adjusting front axl«> t>oarini;8" and page 669. "removing rlhr axle shafts.'* 
tFrom Automobile Dif^est. 



*CLUTCHES : Cone, Disk and Plate Clutch. Universal Joints. 

Purpose of the Clutch. 

The word "dutch" as used in connection with automobiles^ indicates a 
device attached to cars having change speed gears of the sliding type, which 
permits the engine to be connected with, or disconnected from, the trans- 
mission, so that the car may or may not move while the engine is running. 

The clutch is connected and dbsconnected from fly wheel of engine by a 
foot lever. 

When disconnected from fljrwheel of engine then there is no connection 
between the engine and rear axle. 

When clutch is connected with fljrwheel of engine then the power of en- 
gine is connected with rear axle — ^if the gears of transmission are not in 
"neutral" position. 

If gears are in neutral position then the power of engine would end at the 
end of the secondary shaft of transmission (see page 38). 

While other types of transmissions require clutches, they are of special 
kinds, and will not be referred to in this lesson. (The Ford, for instance, uses 
a different principle.) 

Because a steam engine has behind it the pressure of the boiler, it can 
be called on to supply much more than its regular horse power for short 

A gasoline engine has no reserve power to call on, and cannot deliver 
more than a fixed horse power. 

When the gasoline engine is required to start the car, it must overcome 
the inertia of the car. This might be greater than the power of the engine 
could accomplish, and the engine might be stopped instead of the car being 

If the clutch made an immediate connection between the engine and the 
drive, the power of the engine would have to instantly overcome the inertia of 
the standing car. 

The power of the engine coming from the revolving of the fly wheel, 
and the explosion that might be occurring in one of the cylinders, it would 
probably be stopped instead of the car being started. 

If, however, the clutch is made so that the engine takes hold gradually, 
the inertia of the car will be overcome, and it will move faster and faster 
as the clutch permits the engine to apply its power more and more. 

This is done by making the clutch in such a way that when it is applied, 
it dips, instead of instantly making a connection between the engine and the 

When the clutch is "let in," it connects the crank shaft of engine through 
the fly wheel with the transmission through the clutch shaft, and if the gears 
are in the "neJutral" (gears out of mesh) position, the counter or secondary 
shaft in the gear case of transmission will revolve without moving the car. 
See illustration page 50. 

Olntches have two chief parts; one part (usually the flywheel, see chart 19, fig. 1), is 
attaehed to the crank shaft of the engine, the other part (cone or disk or plate) is at- 
tached to the dutch or main shaft of the transmission (see page 48, fig. 1). (134.) 

When the two parts are separated, that is to say ''clutch thrown out" by the clutch 
pedal, they are independent of each other and the engine can run without moving the car. 

*8m Dyka't working model of the clutch and gear box. For repairing clutches, see index. 
For mako of elnteh oa different ear*, see "Specifications of Leading Oars*' — page 548. 



.2.rjiz &s ifr 

"1 Fig. 1— niustrates 
• tzw the cone type 
' cf clutch is fitted 
I into tlie fly wheel. 

Ill ,: stmt ion showa 
?a.z.v in section aa 
if :::: in half. The 
: : - :- is perfectly 
::rcu!ar, but cone 
shaped and fitted 

^ -^r.h leather which ! 

' irrir? the inner sur- j 
fa?e of the fly ! 
wheel rim when 
-•lurch is "In," 
"Which it always is, 
u::!-?«s thrown 

; *;out" by the 
' ; olutch foot pedal 

. I Note in illustra- 
I lion position of cone 
[when clutch ii 
! "in" and "out" 

* Also note clutch 

CE . page 50. 
::• threw clutch out. At 

I . 

.:or ^h.lIt. Noti- tirivo 


> povor :- transmuted from engine to clutch, thence to secondarr 

■ :•;. • ..••:. >l.aft. drive pear (O), secondary ihaft gear I 

.• drive:; ^^mf i - h'..-:iug gears (X) on square shaft (T). ' 

.:'•■-! i% "out." at which time the elntch ' 

/. ■ .•■-:; t.':i' drive and drlTen gears are in *'nen- , 

I' ■.' f:-.- ii. end of clutch shaft, as per fig. 3, 

,U ;ution: N'"'.'" tl.*- p-wf-r from enji:;'' i:-* trar.smitted to the clutch shaft only 
V:o\liiti-h \vi.- f. Ill tli' rin: of tKo :"v v;hov\ .'if disk or plate type, then by the 

. ., ,., ,.v :!:..!.. I • r.-li-- t»;.t tyj.o -.f rlutch). 

!■ .• '\-i>K'\ uiiii ii.irinc, but runs ftee at all times in 

' ^ ' 1 i- ...1 .• ;.:i ..{' .'i.^'li I- .••.liiifctril with the clutch shaft so that 

• .,1. .iinr! ri.u:-t nl-" tun.. Hut obstTve that the cone slides on the 

. , "..', •..;■! v.. :!•:!♦ ;i .Mil h" piKii' 1 out by pedal OP in by the spring. 
...I.. . out. i.f ily \\''M"-i power ends at the fly wheeL 
V iu. I Ml. i)«>\vt»r riids at t!io cud of the secondary or countershaft— if geare 

I ' 

.,iO to VOVt»lVl\ 

Jl.i \ .I'l- in :iIm-\ . 
•■.«• m.:i!iii -: .■•!" * ' i.oi!» tmI' ' and scc in figs. 1, 2 and 3 hon 

I'l V\r''»"'^''^V''. tlio Puiposo of a Clutch and how the engine can run yet not drive the 

,'.!.'. ...t ' ' au.l ' ■ »l'.itrh in.' * 


When the two parts are connected, that is, when the clutch is 'Met in'' hj re- 
ieaaing the elnteh pedal, the part on the transmission shaft is forced into a frictional 
eontaet with the part on the crank shaft or fljwheel by means of a powerful spring and 
held there. The two parts being thus connected forces the transmission to revolve with 
the engine and so drive the car, if gears are not in ''neutral" as has been explained. 

The part on the crank shaft does not grip the part on the clutch or transmission shaft 
immediately, unless they are moving at the same speed. 

If they are moving at different speeds, which is usually the case, or when the part on 
the transmission is stationary, the two parts slip. This riipping continues until the two 
parts revolve at the same speed, when they bind together firmly. When "thrown out" 
they muBt separate instantly. 

A disk or any other type of clutch used with the gear type of transmission is placed 
in the same relative position; back of fly wheel, between the fly wheel and gear ease. 
Although the construction may vary, the reader will note that the dutch principle is nee* 
•osary on all cars. 

Clutch pedals — The left foot pedal on all cars of standard design, is the dntdi pedal 
and on the right the foot brake pedal. See ''operating a car." 

Types of Clutches. 

There are four types of clutches in general use ; the cone, disk, plate, and 
fezpanding type. 

The disk clutch (formerly called the multiple disk) is a clutch with more 
than three disks and can be a lubricated disk clutch or dry disk clutch. A 
{date clutch is one wherein one plate is clamped between two others. 

♦The Cone Clutch— see chart 19. 

This type of clutch is built into the fly wheel, and the fly wheel forma 
one of its parts. The rim of the fly wheel is broad, and the inside of the rim 
is made slightly funnel-shaped, forming the surface against which the other 
part of the clutch presses (fig. 1, chart 19). 

The cone; the other part, called the '^cone," is, as its name indicates 
cone-shaped, and fits into the funnel formed inside the fly wheel rim. The 
surface of the cone that bears against the fly wheel is often covered with 
leather to give good grip (one large manufacturer uses fabric running in oil). 

The hub of the cone has a square hole, so that while it may slide on the 
square part of the clutch shaft which connects to the transmission sleeve 
(see 134, fig. 1, page 48), still the cone and shaft must revolve together. The 
forward end of the clutch shaft rests in a bearing formed in the hub of the 
wheel, so that it is supported, and yet may revolve independently of the fly 

A heavy spring presses the cone against the seat formed in the rkn of 
the fly wheel. 

When the clutch pedal is pressed forward, the cone slides on the shaft 
away from the fly wheel, and separates from it, the spring being compressed 
(see fig. 1, page 38). 

When the clutch pedal is released, the spring presses the cone against its 
seat, and if the crank shaft and sleeve are not making the same number of 
revolutions, the cone will slip. This friction makes the cone act as a brake 
on the crank shaft, slowing it, and at the- same time the cone and sleeve are 
speeded up, so that the cone and fly wheel come to the same speed. 

dutch Operation — cone type as an example. 

Fig. 2, page 38 (also page 50) — note the power from crank shaft of en- 
gine is transmitted to the clutch through friction connection with fly wheel, 
thence through gears, thence to drive shaft to bevel gear drive on the rear axle. 

If engine is running, clutch could be "in" if gears are in "neutral" (not 
in mesh). K gears are in mesh with engine running then rear axle would 
revolve — unless clutch was "out." 

*Sm repair nibjeet for adjasting clatches. 

tl%« cinMindisK thoa elatch is yery seldom used. As has been previously stated, a succeasfu] 
^ m«at be fairly light at the rim. but with the expanding clutch, owing to its method of opera- 

^ this it almost impossible. 



Cliiteh lAlnicatad Type. 

F!^ 2 tk^-wM the paru of the dutch i^p- 
tsim tmsk otiMr. Th« dhks (A) ar* al- 
a vtm faa^ oa «Bciiie ■haft. th« tmaJim 
B. •:« anaehad U the tranwliakwi ahalt. 
'At aad aaaU tfaka (B) as 

Tte nri Sas^vs have pins czteadittf froai than, 
th« taia kaT3^ mlcs m that they may be alipped 

disks OB their snds fit insido of tho 

la* Urso ftaa^. a&d tbe opoaioga in tho 

';ir^ i-iks 7«rai; tk« sMds or pint on the satall 

laxf* so 7mm toroc^ thea. Thaa the outer cdgea 

iisss ecoc in contact with the inner 

af :h« larfe diaka. 

ttSiAi aa will be seen from 

±pzT* 1. «-3:<h is the dntch assembled, the 

art ra^sccted only by the friction 

t^« IsTfe and amall dislca. when the 

rrrizf preasee i^* parts tofother. The entire 

z'lizz'z is placed irside a easing, and mna in oil. 

W)MBi tka dEieh pedal la priaaad forward, 

:^e ei-x:eh is "thrown ont," the oil then 

Siswv b«sw««n the disks, and when tho 

;I'::ci is "is" and the spring presaaa tho 

i:sks :c««tk«r. the oil is sqneesed ool froai 

b<7v<c- s^cB. While it is being sqneesed 

cc: : *■• ::::fich is slipping, and it be^s to bind 

vh*z :b« pressure has sqneesed it out and 

;he disk I in eonsequenco feel the eflteei of 

:=* fr:^':ior- When the clutch is 

one aet of disks may reroiTe isdtpendtfutly of tla oeker. for they are not connected in any way. 

Hele-Shav XMsk CbitclL 

In the Belfr-Sknw diak ditck (^. 4^ a aimaar prtsciple is adopted. The plates consist of a 
of alternate bronae and steel disks mzch tkinncr. T hey are eaRVgaiod to incrcaae tho grip. 
M HA!f tit rVttn s?« rotably ceaBocted by gioofe a with the driring member. 

P aad %h^ mli^rs^u tMH with, the driven member. Wken the dutch pedal la released. 

'- tbe dat<h 9pnx^ pt«efM tkeoe diaka together, and they all rotate aa a aolid 

W%mu Ihc d«l<k p*d»^ is ■ - . . .... 


Ike apring preaaaze ia removed and tho 

Bef erring to the illussratioa (flg. 4) tho outer ott-ttgkt 
caae (1). to wkiek tke driving bronae platoa (16) are 
keyed, is bolted to tke flywked.of the engine. The In- 
ner eore (1) is keyed directly to the dntch ahafi and to 
it arc keyed driven sted platoa (IT). 

The clutck ia akown 
spring (4) which actu 
preaser (8). To facilitate 
springs (26) are fitted between tho diaka. 

engaged aa normally held by tht 
tea the ring (T) and tke aiidlB| 
itate quick diaengagement. amaiJ 

The ease U oil tight,, provision bdrr 
of th« oil thr«titfa a plug (6) for the ^'^ 

AdittttRient^ »f# msde by means cf an sd|iutl^f nxiX {%}, and J 
c>ieaisit« epinniiitc or dragging is prcveiited by a eeue brake (10). 

Fig. 4 — The HeleShaw 
corrugated disk clutch- 
lubricated type. 

CadUlac— Dry Disk ClutdL 

Fig. 6— The drlvliig disks **A'- are covered on both 
sldoH with a friction material, composed largely of as- 
beatosi and aro driviMi by six keys in the clutch ring 
•Ml" whioh is bolted to' tho engine fly wheel *'Q." 

TI16 driven disks • * U " are not covered. These disks 
aro I'lirriiMl on tlio clutch hub **E'* and drive it through 
ail hi'VM <»n the hub. Tho clutch hub is keyed to the 
IrKMHiniNHion Bliuft **1'\** 

Wlioii tho clutch Is engaged by allowing the clutch 
ppdiil l»» «*«»nii' towar«i8 you, tho spring ''CV forces all 
of tho diNliN togt'lhor. Tlio resulting friction between 
thn iIIhUh "A" and *'M" drives the transmission shaft 

' I'"* niiil till' riir. when tho 

transmission control lever ! 
la hi iithiT Ihiin tlio neutral position. 

Thorn iiro no adjustments. The clutch pedal should 
lin iiiljiifil«'i| orraHionnliy to compensate for wear on 
Ihn riiciii^ of tho clutch disks. 

Thn.' In fiiio jioini * ' D * ' on the clutch for lubrication. 

Tl.iiin mr 17 .H'i.| plstcii. havinir 9 driven disks and 8 driv- 
li.i Ti.n iMill R|irini; is held under 300 lbs. compression. 

Fig. S — Th9 Osdilisc 
difk rltitcb — Axj 

////AUT NO. S50 Disk Clutches; lubricated and dry tjrpes. 


Therefore there are three methods of cutting off the power to rear axle; 
(1) stopping engine, (2) by throwing **out" clutch, (3) by having gears in 

The usual method to stop car and engine — is to "throw out" clutch, 
shift gears to "neutral" and apply foot brake. After car stops tiien turn off 
ignition switch and stop engine. 

Wlien startliig engine the gears are placed in "neutral" position by the hand gear 
shift lever. (Note fig. 2, chart 19; also page 50. Gears are now in "neutral" position.) 
Engine can then be started without car moving. 

To 'start car after engine is started; throw "out" clutch with foot pedal — shift 
gears in mesh (usually to lowest gear sot), then gradually let clutch "in." 

The term "clntch in" meaus, the clutch is aUowed to press into the fly wheel by 
tension of spring. 

The term "clutch out" means it is held out by foot clutch pedaJ. If car was run- 
ning and you desired to coast, "throw out" clutch or disengage gears. 

Wlien stopping — throw "clutch out" by movement of foot pedal. (Usually left 
foot pedal.) Apply running brakes (usually right foot pedal.) Shift gears into "neu- 
tral" and then let "clutch in." 

The clutch is used more than any other control on car — therefore study the meaning 
of "clutch in," "clutch out," "gears in neutral." 

When the change speed gear is to be moved to a higher speed after starting or at 
any time when car is in motion or engine running, the clutch must first be "thrown 
out," for the gears could not be meshed with the countershaft revolving and the square 
shaft stationary; "throwing out" the clutch leaves the countershaft free to move as neces- 
sary to mesh .the gears. 

The cons clntch adjustments are simple. Examples are shown in the repair subject. See index. 
The "grabbing" feature is being done away with by insertion of springs^ usually about 6 inserted 
aader the leather. Slipping is overcome by clutch springs within the spider. See Buick clutch ad- 
justment in repair subject. 

The Disk Clutch— see chart 20. 

The disk clutch (formerly termed multiple disk), consists of a number of 
disks which are pressed together when the clutch is "in," the friction 
between them causing one to drive the other. This type of clutch is very 
compact, and is frequently built inside of a metal housing cast to the engine 

To illustrate the principle of the disk clutch, place a silver dollar be- 
tween two silver half-dollars, and squeeze them together between the thumb 
and forefinger of one hand. With the other hand, try to revolve the dollar 
not moving the halves. It requires only a slight squeeze to produce sufficient 
friction to make it impossible to move the dollar. ^ 

Multiple disk clutches are of two general types; those {hat operate in an 
oil bistth and those that run dry ; called lubricated and dry types 

The lubricated disk clutch runs in oil; its disks are usually alternate . 
steel and bronze or all steel disks, and the type that runs dry is usually of 
steel disks, one set of which is faced with a friction material of woven asbestos 

The lubricated and dry types are described in chart 20. 

The Plate Clutch. 

The S. A. E. term the disk clutch (formerly called the multiple disk) ; a « 
clutch with more than three disks. The plate clutch is where one plate is 
clamped between two others. 

The single plate clutch is a popular type of clutch. It is a variation of 
the disk type, the latter comprising a large number of narrow disks, while 
the other usually consists of but three broad disks or plates* the ordinary 
type having two driving plates and one driven plate. 

An example of a single plate clutch is described in detail in the following 
matter. In this type the clutch effect is created by wedging the plate. The 
type which will now be described is the Borg and Beck make (chart 20 A, 
and page 43). 



1 — Olotch-Oasing — cast with fly wheel. 
2 — Oating-Oover — carrying adjustment-ring. 
8 — Oover-Slot — for adjustment-bolt. 
4 — Adiustment-Bolt — for take-up action. 
6 — Adjustment-King — mounts thrust-leTeri. 
6 — Thrust- LeTer (bell-crank) — ^mounts roller. 
7 — Thrust-Roller — acts against thrust-ring. 
8— Thrust-Ring — acts against asbestos ring. 
— DnTing-Pin — for thrust-ring. 

1 — Frirtion-Hinji— ssbpntoi., 

1 1— Friction Diflk — drir^n. 

12 — Pilot B*llBearmg — fop end of abaft 

13 — 01 nt^-h- Shaft — drlTen by di»k. 

14— Thnnt-Sprlog — leli mi *' bel i -crank *■ tm 

15 — Throw-out Oollai^— on throw-<mt iTe«Y«. 
36 — Throw-otit SleeTe^ — eentered on abaft. 
17 — TT) rnw-nnt Tf>kf' — runn -mt f^t ;ri j^. 
18 — Thrust Bali-Bearing — takes throw><mt pu 
19^Brake*PIate — rigid on throw-out yoke. 
20— Brake-Oollar— keyed on shaft. 
2 1 — Detachable-Oasing — self-contained dutch. 
22 — ^Mounting-Flange — bolts against flj whee 
23 — Driving-Bolt — for thrust-ring (not ahowi 
24 — Shaft. Brake and UniTorsal Oonneetlon (i 

25 — Adjustment-Incline — ^take-up seat for roll 
60 — ^Bell-Orank PlTot — mounts thruat-leyer. 

Borg ft Beck Single Plate dutch. 

Principle: This type of clutch runs dry. The action is best understood when it is ke 
in mind that among the revolving parts, only the driven group; disk 11, shaft IS and bra 
collar 20, can stand still when fly wheel is running; and all other parts being ''anchored 
to fly wheel must always revolve and drive with the latter. 

Wlien clutch is "in:" The asbestos friction rings 10, though not positively attached 
either the driving or the driven parts, will, in practice, "freeze" to the unpolidied fa< 
of the inner case of fly wheel and thrust ring 8; and thus always run bodily with the : 

When clutch is "out:'* The foot lever is applied which telescopes the coil spring (1 
back, by action of the throw out sleeve (16) which causes the roller (7) to withdraw a sui 
eient distance from faoe of thrust ring (8), to permit the latter, with its companion fr 
tion ring (10), to "back-away'' bodily, from friction disk (11), thus releasing the disk fr< 
the friction-grip, anil pcrniitting it and other driven parts to come to a stop, while fly wh< 
and parts anchored to it revolve. 

CHABT NO. aO-A— Principle and Construction of a Modem Single Plate Clutch — dry t3rpe. 

Borg and Beck Co., Molino. 111.' -—soo nUo pngos OOS and 842. 

8«« index for "Spf.'ifiratior* of Losidinir Cnrs." for cars ii«!injr this clutch. 



tAdjusting the Single Plate Dry Clutch— per chart 20-A. 
Take up action: The roller seat face of the thrust ring (8), is formed on three, equal 
iaeeeedingy takeup "inclines" (26); the ring being \i inch thicker, at the high end of 
•aeh ''incline" (25), than at the beginning, or low end. The three thrust-levers (6), 
are mounted upon, and equally spaced by, the adjustment ring (6); and this ring is ad- 
justably mounted against the inner face of the cover (2), by means of the adjustment — 
bolts (4) of which there are two, through slots (3) in the cover. 

When the bolts (4), are ''slacked," and shifted in their cover-slots (3), they control and 
shift with them the ring (5), the latter carrying with it the levers and rollers (6 and 7) — 
thus shifting all the rollers to new seats against the non-shifting thrust-ring; and, these 
•eata being further up the ring "inclines" (25), where the inclines are thicker in cross 
•eetion, the ring is necessarily thrust so much further toward the other friction parts, to 
eompensate for any friction wear, and to maintain, at all times, a perfect friction grip. 

Therefore to adjust dutch, the clutch is held entirely out. 

With the clutch thus held "out," it is only necessary to "riaek" the adjustment- 
bolts (4), tap either of them "clockwise," in the slot (3) on cover, a quarter or half Inch, 
or any other distance required, thus shifting the ring (5), carrying the levers and rollers to 
■ew seats, upon thicker sections of the thrust-ring; and thus compensating for th^ frie- 
tion-wear which made the adjustment necessary. 

If too much oil gets into dutch and causes slipping: In this case it will be necessary 
to unscrew the bolts (4) about three turns, have some one hold out clutch and let oil drain 
out. It is also desirable to squirt gasoline into interior of clutch to wash out the oil. 
If slipping continues the trouble is due to oil working into clutch housing and must be 
•eparated from main oil supply of oil pan of engine. 

Removing clutch: First remove transmission. Mark clutch cover that bolts to 
flywheel with punch and corresponding mark on flywheel, in order that it is put back in 
•ame position. Cover plate must not be turned. 

Replacing dutch: There are two asbestos fabric rings; one lays against face of 
fly wheel (10), next, to this comes the driven plate (11), then other friction washer (10). 
The cast thrust ring (8) comes next, but before installing, make sure the driving pins (9) 
tre in place in the inside of the fly wheel rim. Drop thrust ring (8) in position so that 
the three slots fit over pins (9). The adjustment ring (5) with its parts assembled to it 
ihould now be installed. The adjusting ring (5) fastened to the cover plate by means of 
two cap screws and cover plate bolts to fly wheel. 

Olutch brake is provided which comes into action when the clutch pedal is pushed 
ill the way down. Purpose is to stop spinning of transmission gears when clutch is dis- 
engaged. The throw out collar (15) presses against the brake collar (20). The dutch 
brake is mounted on the transmission shaft and is faced with asbestos fabric. 

If worn, trouble will be experienced when shifting gears into first speed when car is 
•landing. Clutch will appear to drag and will continue to drive transmission gears when 
folly duengaged, so it will be difficult to mesh gears. 

To remedy, remove oil pan, have some one hold out clutch, while throw-out dutch 
and collar are examined; to see if collar (20) actually touches brake or not. If it does 
lot, the transmission should be removed and if brake friction facing is in good condition 
10 need of installing a new one. See that the throw-out is not coming in contact with 
brake flange and should be adjusted so that these two points form a contact. 

Note — always remember to drive with foot off the dutch pedal. Make sure dutch 
pedal does not strike or press against toe board. • 

♦Unlyersal Joints. 
A universal Joint is a flexible connection between two 

shafts, which permits one to drive the other, although they may 
not be in line. Refer to figs. 2, 3 and 5 and study the prin- 
ciple. Universal joints are usually placed forward and rear of 
the drive shaft (see page 50). 

Universal joints are necessary on automobiles with shaft 
drive, for while one end of the driving shaft is attached to 
the transmission shaft, which is on the frame^ the other end is 
connected to the axle, and constantly moving up and down as 
the wheels follow the roughness of the road. 

^^^^ ^ If no universal joints 

were used, the shaft would 
jam in its bearings from 
the up and down movement 
of one end of it. 

*UBiTerMl Joint! are alio called cardan joints. See pages 680, 681 for construction of ''universal 
Joints." tSee pages 668 and 842 for other adjustments on Borg and Book clutch. See foot note 
page 662. why gears of transmission arc snmet mes difficult to shift. 




Tli« «ticl&* of 
tliJi unit power 

ii « ■ d cjliad«rt 
ca«t in hloek ; 
vkWet on tide, 
poppet tjrp*; d«« 
t«ehable cylinder 
beid dee index. 
' Vylindpr b • b d, 
rtpUeint of/*) 

lelectiv* %TP9, t 
•peedB «beiia »iid 
reTeme. Olntcb; 
rone t vpe. Gr«af 
sUn l«Ter; ball 
fttid locket typ«. 

Left, foot datch 
pedAl Ukd ri^t, 
foot brkk* p«a«L 

Power is trt>iti' 
milted to rear 
&z1e from end 
of trftnsmitiion 
•baft (npper 

Fig« 1: A aod«rn unit power plmnt, iLe Dort. 

PIQ <t L«aiwlrfl* CJMMrtt. TTi« * M'* T>»> a.r. TM * ii" ryjt* UJ 

Tig, 3: Unit power plant wltb valves in the hpud and a detacbable eylioder bead. (The Oakland 
aU). Tbe bead it d^-iachrd with valvea. TbU di£fera from fif. 1, in that the bead i« dalaclLabl*. bot 
Ibe ▼aUei are not in the bead in 1kg. 1, 

indcr bead. 

Tbe Duick 4 cylinder enrinr unit power plant witb ralvef in the bead and deiacb«ble C7I- 
Note tbe Delro "ainfle nnif elaetrie system ; stMtinc motor, ganerator A04 Ifnltion la 

Flf. 4: TUe Locomobile angina and datcb ftra la oa« nniti but the traasadssloa Is 
onirvrtal Jioiat (T. U. J.) between tbe cinteh and trAnsmistioD — tee alio page 41^9. 

ttparata. Kola 

CHABT KO. 21-~XrDlt Power Pljmt; engUa, eluteh aad tranamiasion mounted ia one unit 
Sep^nttfl Power Plant. Engine and dutch form one unit. Tranamisaion separate. 

(Cbart 22 on paft 00}. 

T]4a Bnirk 4 tylindcr car wai diieontlflned fa 101 T. 




TRANSMISSION: Principle of Operation, Lx)cation, Different Types. 

Principle of a Transmission. 

When a bicyclist wants to race on a level track, he gears up his wheel 
with a larger sprocket so that one revolution of the crank takes him farther. 
Tet if he takes this wheel with this large sprocket on the pedal shaft, out on 
the road where there are hills, he must get off and walk or exert an extra 
lot of power. This clearly shows that if a bicyclist wants to speed while on 
the level and yet take all hills, he must change the drive sprocket. 

The same principle applies to the automobile — therefore the automobile 
is provided with not only two .changes of gears (instead ot sprockets), but it 
has three and sometimes four changes of gears, which gears are contained in 
a gear box usually placed back of the clutch. (See page 38). 

The principle upon which all change-speed gears work is the fact that 
when two cog-wheels or spur gears are meshed together the larger wheel turns 
more slowly than the smaller wheel. 

Ab an example, a cog-wheel with 10 cogs, in mesh with a second wheel 
having 20, would revolve twice as fast as the latter, the explanation being, 
that when the 10 cogs of the smaller wheel have moved round once they will 
have engaged with only 10 cogs of the larger wheel, and therefore will have 
tamed tiie larger wheel through only half a revolution, that is, that it will be 
necessary for the smaller wheel to revolve twice in order that the larger one 
may revolve once. 

•With this piece of elementary information, we will observe that in the 
gear-box (see below) there are two shafts — the upper one coming from the 
engine through the clutch, and the lower one continuing to the back axle. 

Each shaft is fitted with three different sized cog-wheels numbered in 
the illustration 1, 2 and 3; those on the upper shaft are fixed to the shaft 
itself, but those on the lower shaft are able to slide on a keyway, to right 
and left along the shaft. The shaft is not round like the upper one, but is 
iqnaredy so that although the sleeve of cog-wheels can slide backward and 
forward, they cannot revolve independently of the lower shaft. 

In order now to vary the speed of the car, it is only necessary to slide 
the cog-wheels (gears) along the lower shaft until the correct two gears 
come into mesh to form the gearing required. 

The illustration, for instance, shows intermediate speed gear in mesh, but 
were we to move the gears to the right so that wheels 1 and 1 come into 
mesh, we should put the car on its first speed, that is its lowest speed, so 
that with the engine running normally the car would be moving very slowly, 
the driving gear being much smaller than the driven gear. 

When, however the sleeve is moved to the left so that gears 3 and 3 mesn, 
the effect is reversed. Now we have the driving gear much larger than that 
driven, and the result will be that when the engine runs normally the car will 
be traveling at a very high speed. 

*Tbis illustration ii intended to simplify the explcvnation. In actual practice the arrangement 
is sUfhtlj different (see page 46); the sliding gears are usually above, clutch shaft and transmission 
shaft are not eontinnoas as shown and drive shaft connects with transmission main shaft instead of 
foanter shaft. 




Drive 8b«ft 



I. Sliaft drire typ* o' transmission. Trans- 
mounted on frame directly back of clutch and 
i tttkT type. This type used to great extent 
rare cars. TraDsmission of the gear type. 


Fig. 5. Single chain drlTo type of pUnttirj 
transmisaloii. The transmission is mounted to the 
side of the engine. The type of transmission is the 
planetary type. This system Is now seldom used. 



Driving j 

Pinion _ ^ 

Driving Chain ^ 

Doable chain drlTo typo of transmission, 
ion is mounted on frame and is connected 
:ears to a jack shaft. This type used to a 
tnt on trucks. Transmission of the gear 

Fif . 6. Shaft dxlTo typ« of planetary trana 
Bdnlon aa nsod on the Ford. (See Ford Instruc- 

\m tarm ot rrlotlon Drlv* Trmniaiaalfln^ S 

Dvlth gfrm varlabl* trcm tmto^ ^^ *- 

io tmMlmm, ^ m 

The friction disc type of drive of trans- 
Mi on the Carter Car. It is extensively 
rcle Cars. 

Ff«. 7— The method of placing the gear typo ttaaa- 
mission on the rear axle. See also page 204. 

'^Flg. 8 — Four speed selectlTe typo of transmission for a 
double chain driven drive car. 

The only difference between this type and the ono ia 
(Chart 23). is that a jackshaft with bevel gears (N), la 
employed. (See flg. 8 above.) 

When there are four changes of speeds, note that thara 
are three shifting forks (H. J and K). The drive fftar 
(B) is attached to the sleeve (A), which connects with 
engine drive shaft through the clutch. 

A — Sleeve driven by engine. 

B — Gear on sleeve. 

— Gear on countershaft. 

D — Low speed gears. 

E — Second speed gears. 

V — Third speed gears. 

G — Clutch for high speed. 

H — Rod and arm for third and high speed. 

.7 — Rod and arm for low and second speed. 

K — Rod and arm for reverse. 

L — Finger in groove. 

M — Guide plate for selective lever, also called a 

N — Bevel gears to jack shaft. 
O — Idler for reverse. 

24 — Location of Gear Box (Traiimlssion) Four Speed Selective Type Transmiflsioa. 

is oil pape 50). *Sof' patro r.l (footnote) for 4 speed ratio of gearing. 



2 a o^ S's j^s I fl « s s -^ e 


^»« 9 o £ 2 H « 

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.$1— - 

^ = o « 

oj 00 fl p 3; ^ It 

*J *-■ s © 








13 F-: 



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-3 IS -5 8 

> ^ » CO P 

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OHABT NO. 23 — Simplified Illustrations Explaining the Principle of Operation and the Ohaagv 
Qeaxs in a Selective Type of Transmission with Three Speeds Forward and Bereane. Note 
in modern transmisidoiis the transmission shaft (130) gets horizontally over the eoonti 
shaft as per page 44. Another change made in some transmissions, is the eUminatioB 
dogs (189): the gear (128) fits internally into the main drive gear (8G-1). See page SO. 

*Al«o called "secondary shaft." 


The Selective Gear Type Transmission. 

This type is preferable, due to absence of noise of gears and 
ease q| operation. The gear change ratio or gear desired, is 
** selected" by movement of the gear 
shift lever and the shift can be made 
without one gear passing through an- 

Belatlon of the gears to the clutch is shown 
in fig. 7y and llg. 2, page 38. Principle of the 
selective type transmission is shown on pages 
48 and 60. 

Referring to fig. 7, note power Is transmitted ftom fly wheel to clutch, thence clutch 
tfhalt to gear O and 8, through sliding ^car for 1st or 2nd speed. For high speed, smaU 
dog elutches on sliding gear X, on square shaft (T), mesh with dogs on gear O, which 
makes the drive direct to rear axle, see fig. 3, page 48. 

Operation of the Oear Shift Lever. 
There are two types of gear shift levers; the "gate" principle as per 
figs. 4 and 2 below, and the "ball and socket" type shown in fig. 1. The latter 
being used more than any other type. 

A itanplified explanation of how the parts operate is shown in fig. 4. If the reader 
will first refer to page 48 he will understand just how the shift lever operates in relation 
to the shift bars (146 and 147) and shifting gears (SG-l and SG-2). Further detail will 
be given below as follows: ^ _ 

^^ By moving lever (73) in, to the 

left, the arm (145) engages with 
gear shift bar (146). Then by 
moving it (73) forward or back- 
wards, the sliding gear (8G-1) is 
moved to "second" or "high" 
speed engagement. 

Fif. 4: View showing how the gear shift- 
tag tow and selector connects with the 
■Uftinf bars. Lever is now in * 'neutral" 
position, bat if pushed to the inside it M'ould 
ikift the inside bars (146)— if pushed to 
osUide position it would shift the outbide 
btrs (147). 


By moving (73) out, to the 
right, this action causes arm 
(145) to engage shifting bar 
(147) which shifts sliding gear 
(SG-2) forward; forward move- 
ment of lever (73) throws slid- 
ing gear (SG-2) in mesh with "reverse" speed gear on counter shaft, while a backward 
Biorement throws (8G-2) in mesh with '*low" speed gear. 

__ _ When lever (73) is erect and in between the two slots as 

shown in illustration fig. 4, the slots which (145) work in are 
in line and all gears are out of mesh, or in "neutral** as it 
is called. For instance, the gears in fig. 2, page 48 are out 
of mesh, and slots on shifting bars are in line, therefore gears 
are in neutraL 

Gate type: by studying the il- 
lustration fig. 2 on page 48 and 
figs. 4 and 2 on this page, the 
reader will readily see how the 
gears are shifted. 

The lever (73), the gate or 
selector (76), and the other 
parts are numbered and named. 

Note this lever moves side- 
wise as well as forward and back- 
ward (see figs. 4 and 2). 

The ball and socket type of 
gear shift lever is identically the 
same principle except the move- 
ment of lever (73), fig. 1, is in 
a ball and socket instead of a 

gate. Note arm (145) serves the Pig. i. — Ball and Bocket type 
same purpose as arm (145), fig. 4, of gear shift lever (73) is now 
above This tvne ia the tvrie "tanding upright in cent»»r of 
aoove. inis lype is me lype ^j^^ .o^ket and is in "neutral** 
in general use. position. 

tng. 2. — Oafce type of gear 
shift lever is now in "neu- 
tral" position (M). The 
hand or emergency brake 
lever to the nght is "aet" 
oatil ready to sUrt car. (1) 
la **low speed" position; 
(2), "aecond or intermedi- 
•U;" (S) U "high" speed; 
(E) reverse. Movements 
rsry on different esrs. (See 
iadez "gesr shifts of Issd- 
iBff cars.") 

*Vots ths movement of gear shift lever in fig. 2. This is the type used on the Overland model 85. 

na B0TeB«it of Iffvsr (7S) in fig. 4 vsrlss slightly from movement of lever in fig. 2 this psgs. 
Wm laffrnrrn If lever (78) in fig. 4. it shifted in to the left and back, we would have 3rd or kigk 
ipesA; if to tiM Uuft forward. 2nd spaed; if to the right side and backwards. 1st or low speed and if Ui 
tts tit^t side, fonrsrd, nffscse speed. (Set fig. 4 this page and fig. 2. page 48). 
TTkls is the standard 8: A. E. three speed gear shift. Illustration is that of the Overland, see 
SMM 490, 497 snd 858. 


OHABT NO. 2S&— Principle and Operation of a Single Plate Olutdi (see page 42), fl^lectiye Tj9 
of Trannmlwrion and Method of Driving Bear Axle. A modem Unit Power Ptant Tb 
clutch may be of any one of three types; cone, disk or plate. The tranemisrioii is a thre 
speed and reverse type. 

(Ohmrt 38 i» on pace 48). 


How the Various Speeds are Obtained 
By Shifting Gears. 

NOTE — The dutch is always engaged or in — unless held out by clutch 
pedal. Therefore gears must be out of mesh or in neutral before starting 

When shifting gears, engine is supposed to be running, therefore always 
hold clutch out while moving the change or shift. 

Never shift from high to low gear, unless ear is slowed down to a very 
low speed. 

Obtaining Various Speeds. 
Before describing the operation of changing speeds, it is most important to 
aotiee in chart 22, that the main shaft of the transmission (4) is not square 
eontinnously right through the gear box. One end (E) works free into end 
of clutch shaft, so when gears are in ** neutral" or not in mesh, there is no con- 
nection between clutch and transmission. A study of fig. 3, chart 23, will 
assist the reader in understanding this. Also note remarks under ''clutch 
shaft'' in chart 22. 

''Neutral;" by observing the position of gears, it will be noticed that none 
of the gears are in mesh except the main clutch drive gear (9) (called clutch 
gear), connected with the clutch shaft and the gear (SS) on the countershaft. 
If we then follow the dotted lines and arrows it will be noticed that the coun- 
tershaft (22) and gears (23, 21, 20) thereon are free to revolve. 

Low or 1st speed: the gear shift lever (1) is brought to the center, and 
then drawn side wise until the lower end of lever engages with shift bar 
which oprates (6). This gear (5) is then moved into mesh with gear (21). 
The power then is from gear (9) to (SS), thence (21) to gear (5), thence 
square shaft to propeller or drive shaft. 

Intermediate or 2nd speed — is obtained by returning the gear shifting 
lever to "neutral" (straight up and down, position illustration shows lever 
now) ; then putting end of shift lever (1) in shift bar which connects with 
(7). Push lever forward, this will slide gear (8) into mesh with gear (23). 
Note dotted lines then for the transmission of power. 

High or 3rd speed — also called "direct" drive: Pull lever (1) straight 
back. This will shift sliding gear (8) over gear (9). 

The drive is then direct through gear (9) and gear (8), through square 
shaft to rear axle. The action causes gear (9) to partially mesh inside of gear 
(8), as gear (8) is fitted wiht internal teeth. The former method was by 
means of "dogs" (139), fig. 2, chart 23. 

The engagement of these two gears cause the top transmission or square 
shaft to be engaged direct with the clutch shaft and continuous right through 
to rear axle. 

During the time that the direct drive is on, it will be noticed that the 
countershaft or secondary shaft (22) although doing no work, is still running. 
In a few instances, makers have arranged that this should be thrown out of 
action as soon as direct drive is on, but owing to the diflficulty in connecting 
it up again when the second speed is wanted, it is now generally allowed to 
remain in mesh. 

♦Reverse: When the "reverse speed" is required the gear shift lever 
IS brought to "neutral," then pushed forward to mesh gears (5 and 20). There 
are now five gears in operation instead of only four, as for first and second 
speeds, and the result is that the square shaft (4) turns backwards. 

*T1m rcrerie pinion it set lower down in the transmission case and slightly nnder the counter- 
«Uft hMiire It in not possible to s^e it. Charging gears, see v&iscs 486, 488. 

Th« Xiocomobll* and Pierce Arrow use a four sneed transmlBsion. The direct or hi;;h gear drive 
ii OB the fourth speed. On the model 22 and 22A Winton the direct drive was on the third speed and 
the fourth speed was geared slightly higher than direct drive — see page 583 



0if7J U<£flfP£ 




•ex^Ausr \rALv& 






Fig. 1— The Oasoline Engine; an internal combustion type 





r^Am ^^SjOoit-£/f T^^AMAt^ 







Fig. 2--Steam Engine; an external combustion type. 



freAff Atj^B. 

Fig. 3— The Electric Motor and its source of electric supply; the storage battery. 

OHABT NO. 25 — ^The Three Motive Powers; Gasoline Engine, Steam Engine, Electric Motor. 

Note — An eccentric (E) on a tteam enirine is for the same purpose as a cam on a gaaoline engine: i. e. 
to open the valve. Although, the word "explosion" is used, under fig. 1, the correct term U com- 
bustion" — see seventh paragraph, page 58. 


j^SArrEFY I 



*THE GASOLINE ENGINE: General Explanation, Cycle Prin- 
ciple Explained. Construction of the Gasoline Engine. 
Assembling a Four Cylinder Engine. Speed Control of 

General Explanation. 
There are three motive powers for automobiles. (1) the gasoline engine, 
also called an **intemal combustion type of engine in which the fuel combusts 
inside of the engine, between cylinder head and piston or the combustion 
chamber. This type of engine could use either gasoline, kerosene or alcohol, 
but in this treatise we will deal with gasoline as a fuel. (2) the steam engine 
is an external combustion type. The combustion taking place under the 
boiler, separate from the engine. (3) the electric motor (shown in chart 25), 
derives its power from an electric storage battery. 

Gasoline engines: We will deal with the gasoline engine type of auto- 
mobile. The gasoline engine furnishes the motive power to drive the automo> 

Engines for small cars are sometimes made with but one, or perhaps two 
cylinders (now obsolete). A few motor cars formerly had engines of three 
cylinders. The majority have four, six and eight. BHve-cylinder engines 
hardly exist. Seven-cylinder engines exist in a special form for flying ma- 
chine, as the Gnome revolving cylinder type. The ttwelve-cylinder engine 
is also coming into prominence ; motor boats indulge in engines with as many 
as 12 to 24 cylinders. But whether the engine has 1 or 24 cylinders, the ex- 
planation of how it works or the principle, always remains the same. 

All gasoline engines work on practically the same principle. It must be 
a four cycle or a two cycle type (four cycle is dealt with in this instruction). 
The valve arrangement may be different, but we describe the various types of 
valves further on in this instruction. The ignition may be diflPerent, but we 
cover all forms of ignition. We mention this so that when you see an engine 
with a diflferent ignition or a different valve arrangement, remember the prin- 
ciple is just the same on all engines (except the two cycle type, which have 
no valves. The principle of combustion and ignition is similar, however). 

Gasoline engines belong to the class known as internal combustion type 
of engine. This name is used to distinguish them from steam engines, which 
are of the external combustion class, for the heat that a steam engine turns 
into power is produced outside the engine, under a boiler. 

In a gasoline engine, the combustion, or in other words, the burning of 
the fuel, takes place inside of the cylinder of the engine, the fuel being 

When a mixture of gasoline vapor and air ir set on fire, it bums with 
great rapidity and produces intense heat, which expands and develops the 
pressure against the head of the piston, which operates the crankshaft of the 
engine. This combustion is so rapid that it is usually spoken of as an ex- 
plosion; and that word is often used, although the word combustion is more 

*For enirine repairs and adjuttments, see subject of repairing. **The gasoline engine is also called 
a "hydrocarbon*' type of engine. 

tThe "tweWe" cylinder engine was formerly referred to as the type used on motor boats, where 
th^ twelve cylinders were in line. The "twin six" is referred to as the type used on automobiles, 
with cylinders placed •'V** type. However, both terms are used. "Twelve or eight cylinders *V* 
type " would be the proper term. 

mot*— Th« word motor ii often nsed to deiicnate tlie engine, but if one wishes to be technical and 
correct it should always be referred to as engine. The word "motor," however (owing to the popu- 
lar practice), is used in many instances in the book. 


The Four Cycle Gasoline Engine *nd Its Parts 

Wbeo Jo doubt as to the oajxie» of any t>Arts of the eogine refer to this chart 

The type of Tslvet (hoth intake snd eshanst) oo this engine are called ^'mechanically 
operated valves,'* 

The type of cylinder 19 the ^*T*Head type/* iviih the exhaust valves oo one side and the 
intake valves on the opposite. 

tOBAftT NO. 2&^A Four Cycle Gasoline Engine Showing a Sectional View T hend type 
cylinder, valves are of the poppet type and are rnef'hanically operated- Wrth the 
T-head type of cylinder the int^ake valves are placed on one side and the exhaust 
valves on the other side^therefore two cam shafts and two cam gears are required. 
'Sea index for Two Cycle Eofistt. 




The difference is that an explosion is instantaneous, while the combus- 
tion of gasoline vapor and air, although very rapid, is not instantaneous. The 
eombustion takes place within the cylinder of the engine. 

One end of the cylinder is dosed, and the other is open, the closed 
end being called the cylinder head. Within the cylinder is a piflton, sliding 
back and forth. 

The space between the piston and the cylinder head is called the combus- 
tion chunber. 

The back-and-forth motion of the piston in the cylinder is called recipro- 
cating motion. In order that it may turn the wheels, this reciprocating mo- 
tion must be changed to the motion of a wheel revolving on its axle, which is 
called rotary motion. The reciprocating motion of the piston is changed to 
the rotary motion of the wheels by means of a crank shaft. 

The piston is connected to the crank shaft by a connecting rod, so that 
it moves in and out as the crank shaft revolves. One complete turn of the 
erank shaft, by which the piston is moved from one end of the cylinder to the 
other, and back again, is called a revolution. One-half of a revolution of the 
crank shaft moves the piston from one end of the cylinder to the other, and 
this is called a stroke. 

It jamat be remembered that there are two strokes of the piston to every 
rtvolntion of the crank shaft; one down-stroke and one up-stroke. 

A steam engine is called double-acting, because the pressure of the steam 
•eta on both sides of the piston. 

A gasoline engine is called single acting, because the pressure acts on 
only one side of the piston ; on the top or side nearest to the cylinder head. 

The combustion that causes the pressure that operates the engine, takes 
place between the cylinder head and the piston, in the combustion chamber. 
nie combustion should be timed to occur so that the greatest pressure is ex- 
erted when the piston is nearest the cylinder head. The pressure causes the 
piston to slide the length of the cylinder, from the head toward the open end. 

In a steam engine, the pressure of the steam forces the piston to slide 
lint one way and then the other. 

In a gasoline automobile engine the pressure from the combustion acts 
on only one side of the piston, forcing it to slide only one way. After being 
forced downward, the piston must be brought upward again, and this is done 
by a heavy *fly wheel attached to the crank shaft. With the downward mo- 
tion of the piston, the fly wheel starts revolving. When once started, the fly 
wheel continues to revolve until friction or some other resistance stops it, but 
before this can happen the pressure is again exerted, keeping it going. 

tThe fly wheel being attached to the crank shaft, they revolve together, 
and because the piston is connected to the crank shaft by the connecting rod 
it moves with them. The piston moved downward by the pressure, starts the 
crank shaft and fly wheel, and then the fly wheel in continuing to revolve 
moves the crank shaft and piston. 

Because a gasoline engine does not operate with continuous pressure, 
during its action the piston first moves the crank shaft and fly wheel, and then 
the fly wheel and crank shaft move the piston. 

Before there can be a combustion of mixture in the cylinder, the mixture 
must be drawn into the cylinder, through the inlet valve. 

When in the cylinder, the mixture must be prepared, so that it ignites, 
bums and expands with the greatest possible rapidity and heat. 

•Largwr Hj whMls «r« used on single cylinder engines than on mnltlple cylinder engines, becaase 
there are not as many firing impulses to two revolutions of crankshaft on a single cylinder engine. 

tThe fly wheel is nsually fitted securely to tapered end of crankshaft and flange, per (92) page 62. It 
mast Ve secnre. else a knock would occur, per page 638. 


[ CHART NO. 27— Dlfl6r«nt Tiews o! th9 Outsido o! a Four Cyliodor Gasoline Engine with 
^^m_ cylinders oast In pairs. Valves are mechanically operated. Exhaust valves on oae 

^B side and the intake valves on the other side. Ignition by magneto. Water clc 

^^ dilation by pump. 

r KOTE— 'Tlim 'i'" h<>ad lypc of vng^ine could be roastnucted with tho inlet tnd ej^hauxt reverted if necetMry. 
I Por iattfttico, ialet could be oa the rifbt vido of engine ftnd exbsutl on ih« left tide, at thown In chart 9A. | 

I iChMH No, 28 on page 60). 


After the mixture has been burned, the useless gases must be removed, 
or exhausted from the cylinder, to make rooin for a fresh charge of the mixture. 

These successive events must occur in their proper order, for if any one 
of them fails, or it is not performed properly, the following event cannot 
occur, and the engine will stop running. *These events are (»lled a cycle. 

The Four Cycle Principle. 

There are two distinct cycle principles; generally spoken of as ''four 
stroke cycle" and **two stroke cycle" principles. The two cycle engine is 
generally a small marine type of engine and will be dealt with under marine 
engine instruction. 

The four cycle engine is the type used for automobile work, therefore we 
will deal with this type throughout the automobile instruction. 

The cycle is thus composed of: 1st, the drawing into the cylinder of the 
mixture; 2d, the compressictn of the mixture; 3d, the burning or ignition of 
the mixture and the forcing downward of the piston by the pressure pro- 
duced by the burning of the mixture ; 4th, the removal of the burned and use- 
less gases left after the combustion. 

The cycle is performed during two revolutions of the crank shaft, or, 
what is the same thing, four strokes of the piston. 

The first event occurs while the piston makes a downward stroke, during 
which the cylinder is sucked full of the mixture, just as a similar stroke of a 
pump or S3rringe sucks in a liquid: this is called the inlet stroke or suctien 

The next stroke of the piston is an upward stroke, during which the 
mixture sucked into the cylinder is prepared by being compressed, and at the 
end or top of this stroke it is set on fire, or ignited : this is called the compres- 
iloii stroke. 

When the compressed gas is ignited the pressure from the combustion 
forces the piston to make a downward stroke; this is called the power stroke. 

The next upward movement of the piston pushes the burned and useless 
gases out of the cylinder : this is called the exhaust stroke. 

In principle the gasoline engine is like a gun. In a gun the shot is fired 
by exploding powder behind it — ^in a gasoline engine we explode gasoline be- 
hind the piston in exactly the same way. 

There are some differences, of course When the charge goes out of the 
gnn, that is the end of it. But in a gasoline engine, after the explosion drives 
tiie piston before it, in order to get any work out of the machine, this piston 
must come back and a new charge must be exploded behind it. The burnt 
gases and heat must be disposed of and all of these things must be done over 
and over again very quickly at exactly the right time. 

Valves are arranged to open and close at the proper time to admit fresh 
gas and to let out the burned gas, and the positions of the piston, valves and 
earns for each function are shown on chart 29. Note the direction in which 
the cams are turned by the cam gears. 

Explanation of The Four Strokes. 

Fig. 1: In the first diagram, chart 29, the piston is at the beginning of 
the down stroke on suction, and the arrows show the direction in which it is 

Fig. 2: In the second diagram, the piston has completed its suction 
stroke and is now starting up on its compression stroke. 

*The word Oycle really refers to the complete operation of the four itrokeB of piston to complete 
the cycle CTolntion. Therefore to distinguish the engine with four movements of piston, from the 
engine with two movements of pistons to complete the cycle evolution, we will call them: "four cycle" 
and ''two cycle" types of engines. 





y± REVOlOftort CAM^ 

£r. CAM 

rCftANK S/tAi 
'/a. Size Of 
CAM 6£A/r. 









tNLET CAM §iAfl^ 

inlbt cam, 



Fig. 1. Snctlon stroke; note charge of gas being 
taken into cylinder from carburetor by the suction of 
piston through the open inlet valve. 
Note inlet valve opened by inlet cam. Note direc- 
tion of travel of cam, also note this stroke is also 
called * 'admission" or * 'inlet" stroke. 
Fig. 2. OomprMsion stroke; note both valves are 
closed because nose of cam is not raising either of 
the valves. Note travel of cam. 

Fig. S. Power stroke; note the spark is now occur- 
ring, therefore the compressed gas is combusting. 
(Bee page 61, note in actual practice, spark occurs 
before combustion takes place.) Both valves are closed. 
This stroke is also called "explosion" or "working" 

Fig. 4. Exhaust stroke; note the exhaust valve cam 
is now raising the exhaust valve. The burnt gas is 
being forced out the exhaust pipe through muffler. 
This stroke is also called "scavening" stroke. 

When piston reaches top of ezh&nit itroke the ; 

ton will have completed the four strokes, or two eri 

revolutions, and cam shaft one revohitioii. 

The next stroke is the suction stroke again. Tli 

four strokes are repeated over and over again aa 1 

as engine runs. 

The above explanation of the foor atrokes la «splAl 

with a "T" head type of engine, supposed to be 

in half and standing in front of engine. 

The "L" head uses but one cam shaft, there is 

one inlet and one exhaust cam for each cylinder. J 

the same as a "T" or "round" head cylinder or 

type of four cycle engine. The principle ia identiei 

the same. 

Fig. 6, iUnstrates the morement of tiM earn; note 

cam moves 90 degrees or one-fonrth rerrdhition, e 

time the crank moves 180 degrees or one-half t\ 


OHABT NO. 21)— The Four Cycle or Four Stroke Principle Explained, 
ejele" engines. 
(Chart No. 28 on page 60. Ohart 80 on page 70). 

See index for 


Fig. 3: The piston has now completed its compression stroke and the 
compressed gas is being ignited by the spark at spark plug gap. This 
Ignitioii of the gas causes the combustion to take place and piston travels 
down with foroe, the amount of force being governed by the amount of com- 
pressed gas which was admitted to cylinder by throttle of carburetor. This 
down stroke is called the power stroke. 

Fig. 4: The piston has now completed it^s power stroke and is coming 
up on exhaust stroke, pushing burned and useless gas out exhaust valve. 

Note the inlet valve is raised to admit the suction of gas (Sg. 1) and 
•xhanst valve is raised to permit the burned gas to be discharged. During 
the other two strokes (compression and power strokes), the valves are 

fThe reason for first cranking an engine to start it is due to the fact that 
a charge of gas must first be drawn into cylinder by the suction stroke, then 
eompressed. After the gas is ignited, then the force of the power stroke, 
win give more turn to the fiy wheel which carries the piston through the 
other three strokes until power stroke is reached again. (See page 116.) 

Therefore, during three strokes (suction, compression and exhaust), the 
engine is not developing power. There being only one power stroke out of 
the four. 

In starting the engine with the starting crank, the spark lever (chart 
88) must be retarded so that combustion occurs when the piston has begiln 
to move downward on the power stroke, otherwise it will fire before piston 
reaches the top and run backwards for half a revolution termed '' kicking or 
baek firing.'' 

Additional Explanations of the Four Strokes. 

As explained four evnents, called the cycle, occur in the cylinder of a gasoline en- 
ciae during every two revolutions of the crank, or, what is the same thing, during every 
four itrokes. 

The strokes of the piston during the events of the cycle (as stated previously), are 

^ the: 

-"Inlet" or suction" or "admission" or "inspiration" stroke, fig. 1, chart 
19. 9d— "Compression" stroke, fig. 2. 8d — "Power" or "firing" or "working" or 
"axploflion" stroke, fig. 3. 4th— -"Exhaust" or "scavenge" stroke, fig. 4. These wiU be 
dateribed in their proper order. 

^floctton stroke; the inlet stroke is a downward stroke of the piston, sucks in the 
aildoaive mixture. Note fig. 1, chart 29. 

The speed of the engine is governed by the amount of gas drawn into cylinder 
lirongh the throttle valve of carburetor (page 66). If high speed is desired, it is 
■•eeasary that all of the mixture possible may be sucked in, for it is clear that if the 
^Under is only partly filled not as much power wiU be developed as would result from 
a fun charge. There must be no obstruction in the inlet pipe to prevent the mixture 
from entering the cylinder easily, and the inlet valve must open wide enough to admit 
tha fun charge. (Bee chart 28, 33 and 106.) 

Afl the inlet valve is mechanically operated, the cam must be adjusted (by having the 
lalat cam gear properly meshed with the crank shaft gear) so that it will open the valve 
promptly as soon as the sucking action of the piston commences, which it is just beginning 
to do in fig. 1, chart 29. Note the cam is just starting to raise the inlet valve. 

If all the openings into the cylinder, as the exhaust valve, the spark plug, piston 
rings, relief eock, etc. — are not tight, air or gas will be sucked into the cylinder 
through them at the same time that the charge enters through the inlet valve, and 
this would destroy the proportions of the mixture. 

If the inlet valve does not open soon enougli, the piston will have made part of its 
stroke before the charge begins to enter; if it opens too soon, part of the burned gases 
from the previous power stroke will be pushed into the carburetor. 

*8«e Djke's worklaf model No. 1. of the "T" head type of gasoline engine, and the four cylinder 
> Bod^ for the "L" head type of engine. 

tne piston of A tteam engine roovea at toon as steam is admitted to the cylinder— beeanae 
...Jtaro «ziata in boUor — therefore it is self-starting. There is no pressure in a gasoline engine on- 
m H la nuiniaf — therefore it is not self-starting. The crank shaft must be turned by hand or an 
dortriea! or mtehanical device. 



^ Sparle Plus virs 

Fig. 1. In t]il8 view we are looking it the end of the engine. Imagine end cylinder cat in half. 

The object Is to llliutrate how the gasoline from the tank flows to the carburetor and fllU the 
float chamber until the float needle cuts off the flow. The gas, mixed with air, is then drawn i&to 
the eylinder by the suction of the piston on the suction stroke. Dnring this suction stroke tho inteke 
▼aWe must be opened by cam (nose shaped affair at bottom of valve lifter) to permit gas to enter cyllndtr. 

After the cylinder Is filled with gas, which is the purpose of the suction stroke, the intake and ax- 
baust valves are closed and the piston on its np stroke (compression stroke) compresses the g»t. At 
the highest point of compression the gas is ignited by the spark at the point of the spark plug aad 
the piston is forced down with considerable force; this is called the explosion stroke. As the piatoa 
travels up again the burnt gas is expelled through the exhaust valve which should open at this tfaBa^ 
and permit the burnt gas to pass out through the exhaust pipe and mnfFIer, this fourth and last stroks to 
complete the operation, is called the exhaust stroka. 

Tka spark oeenrs 
aft spaxk plug whan 
piston is almbst aft 
tha top of coaproa- 
slon stroko. (8ee 
Pig. 3. Ohart 29). 

This spark fs 
cansod to ooenr by a 
coil and battery be- 
i n g eonaeeted to- 
gether at the rlfflit 
time by a "timer or 
commntator" bon- 

The tlBMr arm is 
roTQlvod by tko euu 
ahaft to which it is 
attached. Thereforv 
It revolvea onee and 
makea one contact 
during two revolu- 
tions of crank shaft, 
if a single cylinder 
engine. If a four 
cylinder, there would 
be four contact aag- 
ments for arm to 
touch during one 

If a magneto ia 
used for igniton, as 
in Pig. 1. then the 
magneto is run from 
cam shaft and con- 
tact is made by an 
' 'interrupter* ' arm 
at the right time. 
See Chart 83. 

CHABT NO. 28— Elementary Principle of Carburetion and Ignition; explaining how the gas is 
sucked into Cylinder by down motion of Piston and how the Spark is made to oecnr at the 
correct time. 

(Chart 29 on page 6>3 ) 



If it closes too soon, the cylinder will not get a full charge; if it closes too late, 
part of the mixture will be pushed out of the cylinder on the compression stroke. 

fComiiression stroke. The next stroke up of the piston is the compression ftioke. 
Am the piston travels up, the mixture cannot escape, therefore it is compressed nntil it 
oeeupies only the space between the inside head of cylinder and head of piston. 

Power or explosion stroke^ at this instant the spark should occur, which ignites 
the compressed gas causing the piston to be forced down with considerable force. This 
force or pressure is governed by the amount of gas and compression space in top of 
cylinder when piston is at its extreme up position. 

Too poor or too rich mixture will not bum as rapidly as a proper mixture, and must 
therefore be ignited sooner. 

In getting the proper time for the ignition of the mixture, it must be remembered 
that it is necessary for the spark to occur at such a time that all of the mixture is to be 
burned just as the piston is at the top of its stroke — ^when the gas is compressed to the 
highest point. 

The contact on timer or commutator, or the magneto contract breaker in the igni- 
tion circuit, is so arranged (see chart 33), that it may be moved, in order that the 
spark may occur in the cylinder at the instant desired by the driver; that is, the spark 
ean be made to occur early or late by movement of the hand spark lever. AdYtiUBing 
the spark is to move the timer or contact breaker, so that the spark will ignite the 
mixture (early) before the piston reaches its upmost point in the cylinder. Betaidlng 
the spark is to move the timer so that the spark occurs later in the stroke, in some 
as the piston reaches its upmost position, or even a trifle after. 

If tlie spariE is advanced too much, all of the mixture will have been burned be- 
fore the piston reaches its upmost point, so that it will be necessary for the fly wheel 
to force the piston upward against the pressure until it gets to its upmost point. This 
strains the engine, and causes a sound that is called an ignition knock; a hard, metaUie 
sound that may be prevented by retarding the spark. 

It is seen from the foregoing that the qieed of the engine may be also oontroUtd 
(in addition to the gas throttle lever; see chart 33) by adyanclng or retarding tbe 
ipKkf the speed of the car changing accordingly. 

Brhanst stroke: during the exhaust stroke, the cylinder is cleared of the burned 
and useless gases that are left from the power stroke. 

Toward the end of the power stroke, there is still pressure in the cylinder, and 
whfm, the exhaust valve is opened this pressure will cause the gases to begin to 

As the exhaust stroke is an upward stroke of the piston, the piston will push out 
tkrongh the exhaust valve all .of the burned gases that do not eseape by their own 

Baek pressure, caused by the muffler or obstructions in the exhaust pipe, will 
prsTont the burned gases from escaping as freely as they otherwise would, and idl may 
not be pushed out by the time that the exhaust valve closes. 

If all the burned gases are not pushed out of the cylinder, it will prevent a fuU 
ehmrgo of fresh gas from being drawn in, which will cause a weak mixture and a weak 

no ezhanst valve closes as the piston reaches its upmost point, or a little after 
it, the inlet valve opening as it closes. 

The exhaust valve and its seat are exposed to the full heat and flame of the 
burning mixture, and are more liable to warp or pit than the inlet valve. 

It must be watched, and if there does not seem to be perfect compression when 
the engine is cranked the probability is that it needs grinding to seat it properly. 

A proper mixture will be entirely burned before the exhaust valve opens. An 
Improper mixture that burns slowly, may still be burning when the exhaust vidve open% 
and will heat the exhaust pipe and muffler so that the pipe may become red hot. Such 
a mixture wastes fuel, and may result in a fire. It may be corrected by making a 
eorreet adjustment of the carburetor and spark, which will be explained later on. 

fHoi* on word "compression** — the word "{'ompression" as used by motorists in such terms ss 
"SoeA oomprossioB" or "wtak compression" refers rather to the compressibility of the engine than 
to the aaonnt of pressare actoaUy obtained in the cylinder, which, of course, varies very mneh with 
tho smonnt of icas admitted to the cylinder durinfr the suction stroke and also to condition of tho 
piston rings and other parts which miirht leak and cause the pressure to decrease. 



A — Upper balf of crank case (42), (turned upside 
down) showing the main bearings (95). Note 
lower half of one of the main bearings at top 
of illustration. 

-Upper half of the crank case (turned upside 
down) showing the crank shaft (92) in place 
in the main bearings. 

— Upper half of the crRnk case (turned upside 
down) showing the connecting rods (93) fitted 
to the crank shaft (92). 

D — Upper half of the crank case (turned 
upside down) showing cam shafts 
(104) and cams (105). Continued on 
page 64. 

Key to Engine Parts. 

Crank Case — 

Upper half (upside down) 42 

Crank case — lower half 90 

Crank ahaft (4 cylinder) 92 

Ply wheel ^ 44 

Starting crank 48 

Main bearings 96 

Connecting Bods 93 

Crank pin bearing 94 

Wrist pin 96 

Piston 97 

Piston rings 98 

Piston pin 96 

Cam Shafts 104 

Cams (nose shape, which raiae the 

Talres) 105 

Valve plunger guide 106 

Oears — 

Drive gear on crank shaft 109 

Cam shaft gear 110-111 

Magneto gear M 

Pump gear 118 

Cylinders — 

Cast in pairs — ' 'T* ' head 89 

Inlet \aive caps 40 

Exhaust valve caps 41 

Pet or relief cocks 116 

.Outlet water connects with radiator. . .116 
Studs for cylinders 117 

Pump — (Water circulating) 49 

Intake water connection 118 

Vatres — (Mechanically operated) — 

Intake gas valves 119 

Exhaust valves 120 

Valve springs 121 

Inlet gas pipe (supports carburtlor 

and passage of gas to cylindera) ... 45 
Exhaust pipe (passes to mufner and 
through muffler the burnt gas is dia- 
charged) 47 

Ignition — 

Magneto, supplies eleetrio current for 

igniting the gas — ^run by gear 58 

Magneto distributor 122 

Contact breaker on magneto 228 

Spark plugs 56 

OHABT NO. 81 — Explaining how a Four Cycle, Four Cylinder Oasoline Engine is Constmctad. If 
the reader will start with illustration (A) and study each carefully he will note different parts are 
added until the engine is completed. 

VOTE: — The S. A. E. now designate the lower part of crank case as the "oil pan^' when containing no bearinga. 
If it contains bearings, it is termed lower crank case. S. A. £. further designate crank cases of the **^it 
jhq^e" and the "barrel type." — In the barrel type the crank shaft is removed from one end of erank ease. 
The bearing caps being removed through hand hole plates. Type shown here and most used, ia the "split type*' 
with the bearings completely in the upper half as at (A). 
(Chart 80. see page 70.) - 


Types of Engines. 

Ab previously mentioned there are several types of engines, all of which 
work on the four cycle principle. In order that the reader may more clearly 
understand we will give an outline illustration of some of the different types 
of engines in general use, see pages 70 and 71. 

The type of engine used more than any other type for automobile work, 
is the four and six, the eight and twelve V cylinder type of engines are also 
popular. We will confine our attention, however, principally to the four. 

Building a Four Cylinder Engine — showing 
the construction, step by step. 

Before the reader can thoroughly grasp the meaning and purpose ef the 
parts, we will build up a four cylinder T-head type of engine as shown in 
eharts 31 and 32. We shall then describe what each part is for, and the vari- 
ous constructions o£ the different parts by different manufacturers. 

Khnuik caie: by referring to tg. A, we have an aluminum crank case, upper half part, 
wUeh we lay on the floor, upside down, so that we can see the bearings (§5). 

Tlie beartngB are made in two halves. The bearings are usuaUj made of bronze or 
white metal and are termed ''bushings" instead of bearings when removable or renew- 
aUa. The bushings are fitted into bearing caps. 

(thin paper or metal strips) are placed between the two halves of the bearing 
■0 that when wear occurs a ''shim" can be taken out and the lost motion taken up. 
Bee index. 

Tbe erank diaft (92, fig. B), wiU now be fitted in jthe bearings. The bolts are 
tightened so that there is no lost motion. 

oannectlng rods (93, fig. C), will now be fitted to the crank shaft. The lower 
half of the large end of the connecting rod, caUed the connecting rod cap, is removed, 
■0 that it ean be fitted to the crank shaft. It is then tightened carefuUy, and shims in- 
nrted so that it works free on the crank shaft, but good and tight, so that thtere wiU 
be no lost motion. If there was lost motion a knock or pound, which would cause wear, 
would be the result. 

Tlie cam shaft (104, fig. D), with the four cams (105, nose shaped) are now 
atted to its bearings. In this engine there are two cam shafts; one with four cams for 
raiMng the four inlet valves, and the other one, with its four cams (105) to raise the 
four exhaust valves. 

The nose of the cams are so placed that they are divided equi-distance apart so that 
n^en they revolve they will raise the valves, by pushing them up with their nose, at a 
eertain given time. The timing gears which operate the cam shafts, wiU be explained 
further on. 

The crank case, is now turned right side up, after having fitted the lower half of the 
erank ease (90) (oil pan). This lower half holds the oil, which the crank shaft splashes 
in (lubrication systems explained farther on). 

The piston or wrist pin (96, tg, £), in small end of connecting rod, is shown in 
the next iUustration. This holds the piston to the end of the connecting rod (details of 
eaeh part wiU be explained further on). 

After the fonr pistons are fitted to the connecting rods, the cylinders (89, fig. F), 
are fitted down over the pistons, being careful not to break the piston rings (98, fig. B). 
(Treated under repair section.) 

The cylinden* (39, fig. F) are bolted to the crank case by nuts fastening to studs 
(117, fig. E). 

The valve lifter guides (106, ^g, F) are fitted in holes in each side of the erank 
ease that thdy wiU come in line with the exhaust valves on one side of the cylinders, and 
the inlet valves on the other side. 

*TMlinleallT th« term "crsnk case lower half" should be **oil pan" and as the term "enuik 
mam lewer kalf'* it used only when it contains the bearings, whereas in this and most enfinee the 
taw«r half is merely an oil pan. 



E — Upper and lower half of crank ca^e with 
Iow«r li»lf of cr&nk cam (90) bolted to upper 
half (42), The uppL*r ball of crank cjisd it 
now turned right iide up. The pistons (97) 
and piston pin or writt pins <90> are showa 
— alio the studs (117), to hold cylinders in 

X* — Tbs eylindsrs (39. cast in pairt^ — ^..-pt* 
head typo) are now holtDd tn crank e*se. 
The TSlve plimgor guides (106) are also 
fltted. The erankib&ft drlTS sw (100) 
Is fitted to erankfihaft (92). The two 
camshsft gears (110) are next applied 
to the cnmshaft (104). 

O — This view shows the Intsks vslres (119> 
in oylinders, intake pips (45) with eu- 
bttrstor. fltted to eylinders, also ma^sCo 
(SB), mounted and geared to one of ths 
cam e^ftri. 

-Showb eiJbaust vslTSS (12O4 opposite side of engine) 

- •liar * — 

with exhaust pipe (47 )» t^llef cocks (41) 
circulating pump (49). The flywliest (44) la also 
moiiDteJ on end of crankihaft, 

^CEBAET KO. 82— Oonstruction of a Pour Cyclo» rour Cylinder Gasoline Bngtno, Continued. Oar- 

ibnTetor, ignition and water circulnting tiyst^m added. 


Valve lifters are now fitted through these valve lifter guides (see shart 26), wUeh 
raise the valves through the action of the cams. 

gear for drlvliig tbe timing gears, called tlie crank diaft timing gear (l^l), 
is keyed or threaded to end of the crank shaft (92); this gear drives the two timiu 
gears (110 and 111). 

^The cam shaft timing gears are keyed to the earn shaft (104), one gear and shafl 
to operate the inlet valves (119), fig. G, and the other gear and shaft to operate the ez- 
kanst valves (120), fig. H. The gear case is filled with grease and a cover is plaeed over 
the gears. (On modem engines the gears run in oil.) 

Tke inlet valves are placed in their seat by passing them through the inlet valve cap 
holes (40). 

The exhaust valves are placed in position, on the opposite side of the cylinders, in 
the same manner. 

The inlet manifold (45) fig. G, is now bolted to the inlet valve side of the cylinders, 
and the carburetor is connected to it. 

The exhaust manifold (47) fig. H, is bolted to the exhaust side of the cylinders, and is 
soBBected with muifler (48) at rear of car, by the exhaust pipe (47); see chart 6. 

The exhaust valve ci^Ni (41) and the inlet valve caps on the opposite side are now 
screwed in place — tightly. 

The priming cups also known as compression or relief cocks (115) fig. H, are screwed 
into the exhaust valve caps. 

epark plugs (66) are screwed into inlet valve caps or in center of each eylinder 
se per page 64, but usually over inlet valves. 

The fly wheel and starting crank (44-43) are fitted to each end of the crank shaft. 
By referring to ^g 0-92, the reader will note the end of crank shaft tapers, and ai 
flange is also turned on this crank shaft. The fly wheel fits to this taper and bolts 
te l^e flange, as there positively must not be any lost motion. 

The magneto (53) fig. G, is bolted in place on a brass base provided for it, on the side 
ef the engine. An extra gear (which will be explained further on) is operated by the 
earn shaft and drives the magneto, which generates electricity. The electricity is die- 
tributed to the four spark plugs (66) at certain periodical times by the distributor cm 
■agaeto (122) fig. O. 

We now connect our wires through switch (66, see chart 1) to magneto. This switch 
is to cut off or turn on the electric ignition. 

The drcnlating pump (49) is connected to the water jacket of cylinders. The 
gear (113) driven by the cam gear, drives the pump, and keeps the water in eonstant 
eireulation, which keeps the cylinders from getting too hot, not over 170 to 180 de- 
grees Fahr. We now connect rubber hose (51) to metal pipes on radiator (60), see chart 1, 
and also to our pump (49) and belt up our fan (62), which is run from the same 
shaft. The radiator is filled with water by unscrewing cap (60, chart 1). 

We now connect the gasoline fuel pipe (62) from gasoline or fuel tank (68, see 
chart 1) with carburetor. 

fStaxting the Engine. 

We now have our engine ready to run (we will presume it has been 
fitted to car as shown in chart 1). 

We now put the gear shift lever in "neutral" position, so the car will 
not move when the engine begins to run. 

The starting crank is revolved, which turns the crank shaft, timing 
gear and moves the pistons, (see chart 26). The crank shaft timing gear 
revolves the cam gears which in turn revolve the cam shaft, and which in 
turn revolves the cams. 

When the cams turn, one of them with its nose pushes up one of the 
eight valves in one of the four cylinders. (There is one intake and one ex- 
haust valve for each cylinder.) We will suppose that this valve being raised 
ii the inlet valve of No. 1 cylinder. As this valve is raised the piston will be 
going down on the suction or intake stroke, as explained in fig. 1, chart 29, 
and dnwi in a charge of gas. 

*Tkm gtmn sr« timed m shown under Talve timing. 

fBm psc* 89 ^hy it is neeessary to start s gasoline engine. 


rif. 1 HhBuumtizu: tte pruicipto •! •ptanc aad ctosiiiff tte tlirottie ▼&!▼• on 

Se^ Chart $ »nd r.o:«^ P:«. ^ ard 5i>Uov the rod Indinc ttuoufh the steering 
column x^' mnd not>f how :t <vcin«fts at i7? , with carburetor. 

OiK'r.inir the butt^rlr throttle Tmlre ^i the cmrboretor admits more gas into the 
ejlindfx, thereby :n<iy«s:zir the speHL Qosing this Talre reduces the 8p<«d. 

At tne $aa^e titfte the thn>ttle Wrer is "^dranced.* the spark lever, which shifts 
the <»nfac: bry^ker on the saci^eox » "adnaced" alaa 

If A ti^er wx:i: a .nv/. *v«f« cif i^\a<KK » VMiL tkca the spark \tTtr (see page 60) 

Tli^ ob^'? ia 4i\*T.',x^ :ke ^^^Mtt a» tite tk^ottle is epcMd, is to canse the gas to 



CIS CT^'C^ ^>^cc1ga1i^«NK^ 

CHART NO. SS-XlemeniaxT Principle of Ooatral of Speed of 

motion of the throttle oad $i>ark. 

; cxplaininf til 


The suction stroke is now completed; the gas which was drawn into the 
g^der must now be compressed. Just as it is compressedt the electric 
ipirk occurs at the point of the spark plug and ignites the gas. 

At the moment the gas is ignited, the force of the explosion forces 
the piston down and this force gives momentum to the fly wheel, which 
will keep the crank shaft in motion until another piston in one of liie four 
flinders has drawn in and compressed its gas and fired. The cycle opera- 
tkm explained in chart 29, is repeated over and over again in each cylinder. 
(See page 116, how a 4 cylinder engine fires.) 

Control of Speed of Engine. 

After the engine is started with starting crank (self starters will be 
explained further on), the speed of engine is controlled by opening and clos- 
ing the throttle of the carburetor which, when opened admits gas to the 
cylinder. The more gas admitted the stronger the explosive force will be, 
hence more speed. The gas of course, is admitted through the inlet valve 
during the suction stroke. 

The opening and closing of throttle is regulated by hand by means of 
the throttle lever (fig. 1, chart 33 and 106) on the steering wheel, or by a foot 
pedal connected with the same throttle lever called an "accelerator." (See 

Oarburetion; the carburetor is connected to the inlet manifold by the 
inkt pipe, and the gasoline flows to it from the supply tank through a 
imall brass or copper pipe, called fuel pipe. 

Pure gasoline vapor will not bum, but must be mixed with air before it 
ean be used to develop pressure. The mixing of gasoline vapor and air in 
the proper proportions is called carburetion. To give the best results, the 
mixture of gasoline vapor and air must always be in correct proportion. 
(See index.) 

There is a passage through the carburetor into which the air is drawn as 
the piston makes the suction stroke. The liquid flows to the carburetor an3 
is brought into contact with the current of air. The gasoline turns to vapor, 
ind is absorbed by the air, the mixture being sucked into the cylinder on the 
inetion stroke. 

The quantity of mixture that is drawn into the cylinder during one suc- 
tion stroke is called the charge. Details of carburetion are given in Instruc- 
tion 12. 

Ignition; when the throttle is being opened and the engine begins to 
ipeed up, it is then necessary to also "advance'' the time of ignition in other 
words, cause the spark to occur sooner than when engine was running slow. 

A spark lever is usually placed on the steering wheel along side of the 
throttle lever, which is connected by a rod and bell crank to the contact 
breaker box on the magneto or if a coil and timer is used, to the timer. (See 
ehart 33 and 106.) 

When the spark lever is moved, it also moves the contact breaker box 
en magneto or commutator, which causes the spark to occur **late'* or 
**early" according to the movement of this lever, (chart 33). 

The reason for advancing the spark is as follows: To begin with, the 
diarge is set on fire, or ignited, at the proper time by an electric spark. 

The current of electricity that supplies the spark is produced by a bat- 
tery, or a magneto or dynamo driven by the engine. 

The exact instant for the ignition of the charge depends on the kind of 
work to be done, the speed of the engine, and the quality of the mixture. If 
die charge is ignited too soon or too late, the engine will not run properly. 


The time of ignition, or instant when the electric spark sets fire to the 
charge is controUed by means of a commutator, timer or contact breakei 
which is advanced or retarded by the driver by means of a spark lever on 
the steering wheel. 

We have up to this time supposed that the spark occurs exactly at the 
moment when the piston reaches the top of the compression stroke. Now, 
this would be its correct timing were it not that the gas takes quite an ap- 
preciable time to explode after being ignited, an interval let us say of 1/24C 
of a second, so that before the gas has had time to burst into a full explosion, 
the piston, on account of its great speed (suppose it is traveling at 1,50C 
revolutions per minute), will have traveled about a quarter of a stroke down 
the cylinder before being affected by it. This means a quarter of everj 
power stroke wasted. 

*Th6 advance of spark; the remedy for this is to make the spark occoi 
a quarter of a stroke earlier; that is, make it occur when the piston has com 
pleted but three-quarters of the compression stroke so that the full burst ol 
explosion and the piston arrive simultaneously at the top of the stroke, or oi 
top ''dead center.'' This is called advancing the spark. 

The retard of spark; suppose the engine is now running at only half th( 
speed, say 700 revolutions per minute. During the exploding or ignitinf 
period, which we assumed to be 1/240 of a second, and which remains th( 
same, the piston, with its speed now reduced, has not time to trave 
so far, and the spark therefore need not be so much advanced. 

Again, when the engine runs dead slow, say at 100 revolutions pel 
minute, which is slow for a motor car engine, the spark requires hardly an] 
advance at all. So that we see at once that the faster the engine runs th< 
more the spark must be advanced, and that the slower the engine runs th( 
less it need be advanced, or, to express it in a more usual way, the mon 
the spark must be retarded. 

Let it be clearly understood that to ''advance" or "retard" the spark 
means to cause the spark to occur earlier or later relatively to the position o: 
the piston. It does not mean that the spark is made to occur more frequently 
or less frequently. 

QaastlOB. — ^How can the spark be made to vary as to the time at which it tak« 

Answer. — ^In chart 33 a device is shown on the magneto which is caUed a ''eoatai 
breaker." This is usoaUy placed on the end of the magneto armature shaft whie! 
Ifl operated by the cam shaft. It is nothing more or less than what we might eall 
rotary or revolving electric switch. For instance, suppose the contact is made o 
dead eenter, but should it be necessary to advance the spark, the contact breaker ea 
be tamed, by means of a spark lever on the steering wheel. This wiU cause th 
•park to be turned on earlier or before the piston has reached the top of the stroke. 

Qaeetionw— Suppose I do not advance the spark when the throttle is opened aa 
engine ie running fast, what thenf 

Answer. — The engine wastes say quarter of every explosion stroke, and fails t 
run to powerfully as it would were the spark properly timed or advanced. 

Qneetion. — What if I advance the spark when the engine runs slowly f 
Answer. — Then there will be a fierce struggle inside the engine; the piston fightia 
to eomplete the compression stroke, and the explosion, which has occurred too oooi 
trying to force it back again. And which winsf If the engine is working f^l 
briik^, the piston overcomes the explosion; otherwise the explosion drives back th 
pieton, and stops the engine 

This is why frequently when an engine is cranked it "kicks back"; the spar 
has been advanced too far, and the piston can't overcome the early explosion. 

QneeHon. — ^How can I tell when the spark is too much advanced? 

Answer. — ^There will be a sound in engine as of a hammer striking the top of tl 
pieton. The engine will be said to knock, and the more the spark is advanced %l 
louder wiU be the knock. 

*Not«. — Lag in the explosion stroke ii ftUo dn* to the electrical apparfttas prodneinf Iho spark, m 
pagoa 808 and 248. *8eo aUo pat** B05 to 809. 


Qnestion. — ^And what should make it knock f Does the piston strike the top 
of ejlinderf 

Answer. — We have already pointed out that this is impossible, as the length of 
the stroke is invariable; neither does it appear that it is caused by a general looseness 
throughout the parts of the engine, since new engines knock as much as old ones. 

A possible explanation, and one which has received some support, is that the 
charge in the cylinder detonates in much the same way as certain solid explosives. 
A piece of gun-cotton, for instance, if laid upon an anvil and lighted with a match, 
bonis silently, because it has all the space to expand in that it requires, but if instead 
of its being lighted it be struck with a hammer, it goes off with a loud report. 

Now, in the ease of the gas exploding in the cylinder, if the piston - is able to 
■ore away from it easily and thus give room for the expansion, there is no noise, 
but if, as in the case we are discussing, the piston moves against the explosion, like the 
hammer falling on the gun-cotton, the result is a report. 

The knocking is not always detected easily by the novice, who will probably con- 
foM it with other sounds on the car, but when once it has made itself evident, the 
•park should be instantly retarded until the knocking ceases. 

The strains set up in an engine which is allowed to knock may seriously damage 
eonneeting rods and cranks. 

An engine should not be slowed by retarding the spark. If it has been noticed 
hy the reader during the last few paragraphs that it is possible to slow an engine by 
retarding the spark, let him at once understand that this is the last method by which 
it ever ought to be done. 

It is not only unscientific, but is also wasteful of fuel, unnecessary work for the 
engine, and causes rapid pitting of the exhaust valves, the gases passing through them 
Sb an incandescent form. 

The correct method of slowing down or Increasing the engine speed is to shut or 
epen the throttle valve, which is situated between the carburetor and the inlet valve, 
bj which the amount of fuel supplied to the engine may be regulated (see illustra- 
tioB, chart 33, fig. 1). Then as the engine varies its speed slower or faster, the spark 
■hoald be retarded or advanced accordingly. 

The mle therefore is to let the engine speed follow the throttle and make the spark 
foUow the engine speed; or to put it in another way, to drive economically, keep the 
throttle valve closed as much as possible and the spark advanced as far as possible, short of 
knocking or tendency to knock. 

Retarding the spark too much produces heat, see page 319. 


Qonsists of a spark plug, a source of electric supply, which may be either a mag- 
leto, generator or battery and coil. If the latter system*, then a timer or commutator is 
ued to make contact from the battery to the coil, causing a spark to occur at the points of 
the spark plug. See fig. 5, chart 39 for an early form of commutator — more modem 
■ethods will be treated further on. 

The spark ping can be placed over center of piston or side of cylinder if overhead 
valves. If side valves; over inlet valve — usuaUy screwed into inlet valve caps — see 
chart 30-A. 

This subject is treated under instruction numbers twelve and thirteen 


The explosion of the charge in the cylinder produces heat. This heat is so intense 
that the lubricating oil will burn and be made useless if the cylinder is not kept fairly 
eooL If the lubricating oil were burned, the friction of the piston against the cylinder 
Wills would be so great that they would cut each other, and the piston would stick, 
stopping the engine. The cylinder must therefore be kept from heating to the point at 
wUeh the lubricating oil would burn, but as the heat develops the pressure, the cylinder 
■nst not be too cool. 

The cjilnder may be cooled either by a current of air, or by water circulating around 
it See instruction number fourteen on the subject of cooling. 

Fuel System. 
There are two fuel ssrstems in general use for feeding the gasoline to the carburetor: 
tte pressure and gravity feed — the two will be explained further on under instruction 
toBiber twelve. 


There are several methods for lubricating the moving parts of an engine, which will 
he fnlly treated further on under instruction number fifteen. 



C^L *S-AP4^ 

ng. 1. A tingle cylinder ver- 
tical type of engine, with air 
cooled cylinder. Valves are both 
on the side and mechanically oper- 
ated. There are two fly wheels 
with a crank pin between them. 
The fly wheels run inside of the 
aluminum crank case. This type 
of engine is used on motorcycles, 
cycle cars, and railroad light cars. 

Fig. 2. A single cylinder horizontal type of engine, with water 
cooled cylinder. Formerly used on light weight automobiles. Seldom 
used, valves mechanically operated. 

Fig. 3. A double cylinder opposed type of engine, with water 
cooled cylinders and mechanically operated vmlves. Note cylinders 
are 180* apart. Oylinders are "L** type. The crank shaft is also 
180* type. 

Fig. 4. A twin cylinder **Y** type of engine, with cylinders 
placed 45° apart. Oylinders air cooled. Valves mechanically oper- 
ated from overhead. Cylinder is the "round" type. This type of 
engine used on motorcycles and cycle cars. 

Fig. 6. A four cylinder Yertical type of engine, with transmis- 
sion and clutch in one housing joined to engine — called a "unit 
power plant." This engine is suspended in 
frame at three points, therefore it would be 
called a "three point suspension" type of 
power plant. Valves all on one side of the 
"L" type cylinders. 

The cylinders are all cast together or "in 
block." The cylinder head is in one piece. (The 

Fig. 6. A six cylinder "nnit power plant." Trans- 
mission, clutch case Join the engine. Cylinders arc cast 
tog«'th«r or "in block." 


Fig. 8. Eight cyl- 
inder "V" type en- 
gine, with cylinders 
placed at an angle 
of 90° apart. One 
cam gear operates 
the valves on both 
sides of the "L" 
shaped cylinders. 
There are four cylin- 
ders on each side, 
usually "in block." 
Crank shaft is a four 
cylinder type (180° ) 
crank, with two con- 
uecting rods to each 
crank pin. 

Fig. 7. A four cylinder engine with cyl- 
inders cast separate. All valves are on one 
side; hence "L" type cylinders. 

OIIAIIT HO. SO— Typei of Four Cycle Gasoline Engines. 
IM*rt S4 on page 74. 


The AutoEiobilo Engine. 
The 4. 6 and 12 cylinder engine is used for 
HutomobUe work. The six is used most. 

Valves are placed on the side or overhnacL 

ition« iisuully coil and battery » uatng a 

lim>'f and distributor. A generator suppUes 

iurri'tit for charging battery^ al»o for lights 

nd ignition. Battery supplies current for 

i^iition and starting motor. Speed of 

mobile engines vary from 150 to 2000 r. 

for in3tHnri\ the Studebaker six 3%" 

ftre X n" stroke engine, and many others. On 

»ine few engines the speed is as high a» 

r. p. m. Control of speed is by a, band 

hrottle lever and foot jtrrclerntor. A governor 

never used. 

The Truck Engine. 

Usually a 4 cylinder engine Is used on 

tSU^a, for reasons stated on page 747. Valves 

nmltr on the side. Ignition usually a bigh- 

t^iiioii magneto and on the Buda engine^ per 

11, 12» used in the Master truck, the 

Eiann magneto with automatic advance, 

f^ge 2S9 and 285 is used. Speed of englno 

r«. 1 1 

is comparativety slow, 950 to 1000 r. p* m. 
Speed Is governed by McCann or Pierce 
governor on this engine, per pages 840, 841 
and for reasons explained on page 839. Stroke 
of piston usually long and m this instance, 
bore is 4 V^^'x^" stroke or 32.4 H. P. (8. A. B.), 
or 52 actual H. P. Truck speed is from IS to 
17 m, p* h. Starting is usually by hand crank 
in connection with an *' impulse starter," 
per page 332. Control of speed by hand 
trottle and accelerator. 

Airplane Engine. 
Blany airplane engines use the overhead 
valves and overhead camshaft as per pages 
912, 916, 918, 921, 922, 930. IgniUon used is 
high-tension magneto or coil and battery 
ignition. Speed of engine at flying speed 
1400 to 1700 r. p. m. Number of cylinders, 
usually 8 or 12. See above mentioned pages 
for further details. 

The Tractor Engine. 
Usually a 4 cylinder engine is used on 

tractors, for reasons stated on pages 753^ 831. 

Valves overhead or on the side and some use 

the overhead 
*'duar^ valve 
system. The stroke 
is usually I o n g , 
average being 4%" 
bore X 6" stroke* 

Speed of engine 
ill? controlled by a 
governor p per fig. 
8, which is a cen- 
trifugal ball- type, 
operating through 
levers to carbure- 
tor throttle (T). 

The governor is 
*' used to maintain 
a uniform speed 
and to prevent 
engine from **rae- 
ing" if load is 
suddenly released, 
of from * * stal- 
ling'^ if load is 

RG. S 

suddenly applied. Speed of engine usually 950 
r. p. m., which speed is usually maintained 
for long periods of time while working. 
Speed of tractor very slow, see pages 830, 831, 

Ignition is usually by means of a high- 
tension magnetOj in connection T^ith an *' im- 
pulse starter". 

Carburetion by means of gasoline to start 
with and kerosene to run on after engine is 
heated up. The heating of fuel around intake 
manifold from exhaust gases is very import* 
ant when using kerosene — see pages 827p 831. 

Cylinder barrels or liners, are used on 
many tractor engines. They consist of re- 
movable liners (fig. 8) placed in cylinder 
blocks, which in case of wear or accident can 
easily be replaced with new ones. 

The reader can now compare the rslatlvs 
difference between the fonr engines and thus 
note, that while the construction may vary, 
the same underlying principles are used. 

CBASf KO. SO A. Relative BliTerence Between the Antomoblle, Track, Airplane and Tractor 




♦ENGINE PARTS: Stationary Parts. Moving Parts. Purpose, 
Principle and Location of Parts. 

The stationary parts are: crank case, upper and lower half, bearings, 
cylinders, exhaust and inlet ports, valve caps, compression or relief cocks, 
water cooling pipes, carburetion and part of the ignition systems, exhaust 
and inlet manifolds. 

The moving parts are: crank shaft, connecting rods, pistons, piston 
rings, piston pin or wrist pin, cams, cam shaft, timing gears, crank shaft 
gear, valves, valve plunger or tappet or lifter. 

Crank Case. 

The cylinder is attached at its open end to the crank case, which forms 
a box around the crank shaft. 

The crank case is of irregular shape, so that while there is plenty of 
room for the cranks and connecting rods to operate, there is little waste 
space. It contains the crank shaft bearings, and forms the bed-plate or 
foundation, for the engine. 

It is of ten made in two parts, an upper part bolted to the cylinder and 
containing the crank shaft bearings, and a lower part enclosing the crank 
shaft and which is called the **oil pan.'*** 

As the lower crank shaft case is intended to contain lubricating oil, it is 
tight so that there may be no leakage. Usually the lower part of crank case 
can be removed for adjustment of bearings. 

The crank case is usually made of aluminum alloy, or if in two pieces, 
the upper may be made of bronze, and the lower of aluminum and some- 
times cast iron. 

The crank case is used to support various parts of the mechanism, like 
the pump, magneto, etc. For an illustration of a crank case, see chart 31, 
fig. A, and chart 32, figs. E and F. 

The arms for supporting the crank case on the chassis are sometimes 
made short to bolt to a sub-frame (22), as shown in chart 5, while other manu- 
facturers make longer arms to extend and bolt to the main frame (21). 

A ''three point suspension" is where the power plant is suspended in 
frame at three points of contact. 

A "unit power plant" is where engine clutch and transmission are in 
one unit as in fig. 6, chart 30 and page 44. 

♦Engine Bearings. 

Engine crank shaft bearings are known as main bearings. Most of the 
manufacturers make four cylinder engines with three main bearings for the 
crank shaft, while others have as many as five. 

On six cylinder crank shafts there are as many as seven bearings, the 
majority using three. See chart 36 and 55. t 

If the six cylinders are cast "single" which is unusual, usually 7 bear- 
ing^; 2 ends and 5 inside are used. If cylinders are cast in "pairs" usually 

*For repairs on eofinei, lee "repairing inetruction." 

^^The 8. A. E. deiignate two typM of crank cases; the "split typo" where the lower part is aop* 
arate and contains no bearings. The lower part is then called the "oil pan." The "barr^ typw' 
li when tho lower part is permanently attached and has a hand hole plate for reaching the boannft. 
and crank shaft is removed from end of crank case with the romoTal of crank easo head. 


3 bearings; 2 ends and 1 inside. If cylinders are cast ''in block," usually 8 
bearings; 2 ends and 1 inside center (small engines). If ball bearings are 
used, Uien there are usually 3 bearings. 

The bearings of a crank shaft are usually in two parts and made of 
bronze or ^white metal babbit, or other metal that does not wear rapidly. 
These bearings are split lengthways into two parts, one part being sup- 
ported by the engine base (called the bearing journal — ^fig. 1, chart 35), 
so that the shaft Ues in it, and the other part covers the shaft at the same 
point, and is held in place by means of cap screws, (see fig. 3, chart 34). 

When one of the main bearings becomes worn the lower cap is removed 
and a shim is taken out so it can be drawn tighter to the shaft. If it is burned 
or cut then a new lining of brass or babbit called a ''bushing" must be put 
in or it can be dressed by scraping. 

' These shims are plates of thin metal placed in both main and connect- 
ing rod bearings (see fig. 2, chart 34), wMch are fitted in between the cap 
and upper part of bearing, so that by removing a shim or two they can be 
drawn closer together when loose. 

A bushing is that part of a plain bearing that the shaft comes in contact 
with. They are usually made of babbit, phosphor bronze or white metal. 
The phosphor bronze are very hard and last a long time, but are somewhat 
liable to "sieze" if run without oil. 

A white metal bushing consists of a layer of white metal, run, (when in a 
molten state), into a channel in the bearing. It then hardens and is scraped 
and polished. White metal has the virtue that if ill treated it does not seize 
and do much damage, but if run for a long time a knock would result. 

Probably the first bearings to require renewal are those of the connect- 
ing rod. See page 641. 

Connecting Sod Bearings. 
The big end of the connecting rod is attached to the crank pin, and a 
boshing of bronze or white metal or other metal (with a melting point lower 
than that of cast iron) in the form of a shell surrounding the crank pin is 
secured in it. (Chart 34, fig. 1.) 

The bushing is split lengthways into two halves, like the bearing of the 
crank shaft, one part being set in the connecting rod and the other being 
held in place by the connecting rod cap. 

The small or upper end of the connecting rod contains a solid bushing 
that forms the wrist or piston pin bearing. (Fig. 1, chart 34.) 

Because of the small space in the piston, it is not possible to have thi8 
bushing split and held in place by a cap. The bushing is therefore set in 
the connecting rod, and the wrist or piston pin pushed through it. The 
wear of the wrist pin bearing is slight, and if it should wear loose, a new 
bronze bushing is driven into the connecting rod. 

The wrist or piston pin is passed through the piston, and secured so that 
it cannot move. (See fig. 4, chart 34.) It is usually case hardened. 

On the Ford, fig 5, the wrist or piston pin moves with the motion of the 
connecting rod. The small end of connecting rod being clamped to it. The 
wrist pin moves in bronze bushings fitted in the piston. 

Through the connecting rod, the piston transmits the pressure of the ex- 
plosions to the crank shaft and fly wheel In order that it may withstand the 
heavy shocks of the explosions, the connecting rod must have great strength. 

It is made of drop forged carbon steel, heat treated and in rare in- 
itaneea bronze. A straight I-beam type is used almost universally. 

*8m ted«z for "whiU meUl bashings." Oonnaotinf rods for high speed engines must be mnde 
Vikt M pOMlUc, hwnf bronte being henrier is seldom used. 





=^\ I -^r-Mn/sr^if 


~ \rojif 

Fig. 0. — A trunk type of piston. 


cojfifecfiw MO 

Fig. 1. — ^A connecting rod show. 
Ing wriit pin bearing and crank 
pin bearing and cap. 




Fig. 4. — Sectional view of pis- 
ton. Note Wrist pin is stationary. 





Fig. 9. — In order to prevent 
compression pMSing tlirongli Joints 
of rings; they are placed as il- 
lustrated. Three rings is the uaual 
number to a piston. 

Fig. 6. — ^Bote in this typf 
(Ford) the wrist pin moves with 
the upper end of connecting rod. 



Fig. 8. — ^Two tjpes of piston 
ring joints. 

Flo. ^-Connectlno-rod bearing end with cap removed to show 


F»0.3 -Crankiltaft i>D3rin0 

Fig. 7. — ^Upper illustration shows a con- 
necting rod, crank pin and crank arm on 
a single cylinder motorcycle or cycle car 
engine. Note crank pin is between the 
two fly wheels which are .placed in the 
crank ease. Lower illustration explains 
the method of connecting two connecting 
rods to one crank pin on a "Y" type en* 

Fig. 2. — Illustrating how shims or liners are 
placed between lower connecting rod cap and upper 
part. When worn a liner can be removed. This 
permits the cap to be drawn closer to crank pin. 

Fig. 8. — Showing bow one of the main crank 
shaft bearings is lined with white metal babbit or 
bronse. Liners or shims are also used. 

OHABT KO. 84— Engliie Parts; bsaxlngs, eoanecting rod, piston, piston rings. 

flote— 8. A. S. baTO discontinued the use of word wrist piu for puton pio which of course is more applicable 
Chart 81 on page 62. 


Gonnectiiig rod on a crank shaft of a "V type engine can be placed 
cither **yoked" or ''side by side" as shown in fig. 7, chart 34. When they 
ire yoked, the cylinders would be '*in line"; if side by side the cylinders 
would be ** staggered" or slightly out of line. See fig. 5, chart 36 of con- 
necting rods on an eight cylinder engine. 

"cpiston and Piston Bing. 

The piston of a gasoline engine is called a trunk piston, to distinguish 
it from the disc piston of a steam engine. (See chart 34, fig. 6.) 

A trunk piston is longer than its diameter, and is hollow, with one closed 
end. The closed end is toward the combustion space, and it is against the 
dosed end that the force of the explosion acts. 

The piston pin passes through the piston, usually about the middle or a 
little nearer the top (dependant on the stroke.) 

The open end of the piston permits the connecting rod to swing from 
side to side. 

•The piston does not fit the cylinder tightly, for a tight fit would cause 
friction and wear. This space is called piston clearance, (see index.) The 
piston is usually slightly smaller at the top than bottom because ^the heat is 
more intense at top and expansion must be allowed for. 

The pressure from the explosion is prevented from escaping between 
the piston and the cylinder wall by piston rings. 

fThe piston rings fit in the groove around the upper end of the piston, 
and there may be from two to five of them, usually three. The rings fit the 
groove snugly, but not so tight that they may not move freely. 

They are cut crossways, so that they may be sprung open. When closed,' 
80 that ends touch, the rings are a trifie smaller than diameter of cylinder. 

When sprung open, they are larger than the diameter, or bore of the 
cylinder. They are so made that they always stand a little open. 

The rings are slipped into the grooves by springing them open, and 
sliding them over the piston. 

When a piston is to be placed" in a cylinder, the rings are drawn to- 
gether (see repair subject), so that they will slide in easily. The piston with 
its rings fits the cylinder snugly, and the elasticity of the rings keeps them 
pressed against the cylinder wall, making a fit that keeps the pressure from 

None of the pressure of the explosion being able to escape, it is all 
exerted against the closed end of the piston, or piston head. 

The rings must be placed on the piston so that the ends are not one over 
the other, for if they were in line the pressure might escape through them. 

The rings are prevented from moving around the piston by pins placed 
between the ends. (Not on all pistons.) The only motion they have is the 
spring in and out. 

The ends of the rings are beveled, or made with a joint that is shaped 
so that it is tight whether the rings are closed or open to the size of cylinder. 

*For piston riog fitting, etc.. see "repair instruction.'* Alnmlnum alloy pistons are now being 
oted to a certain extent instead of cast iron for the following reasons: They are about one-third 
lighter. The inertia of the reciprocating piston is reduced considerably. This cuts down side pros- 
nre or thrust on the walls of the cylinders. This reduces friction and the consumption of lubricating 
oiL The i^eat heat conductivity of aluminum alloy lessens the carbon deposit on the piston head and 
the deposit is more easily removed. In case of extreme heat if the piston seizes or buckles the cylinder 
is not damaged with aluminum pistons. First, there was a little trouble from wear on the skirt; it 
vas diifieiili to get a close enough fit to insure absence of slap without abrasion. The trouble was 
tvercome by one concern, the Franklin, by turning a shallow, square groove of screw thread form from 
the bottom of the skirt to just beneath the lower ring. This holds oil securely and allows a smaUer 
clearance than is possible with a plain piston. Also see page 645 and 651. 637, 792. 

'Pistons and connecting rods must be made lighter for high speed work. Where cast iron is 
ssed, which ii general, the piston is made lighter by making the skirts thinner and piston pin boat, 
Hitter. On small high speed engines the piston skirt is drilled all over with large holes for lightnoas. 

*The usual clearance between a piston and the cylinder wall is explained in repair subject. 
See index for "piston clearance." The maximum clearance is at the upper part, for here the expan- 
don is graatast owing to the heat of the explosion. fPiston rings are measured according to bore of 
cylinder. Soe pages 543 and 8640 for bore of engines on leading cars. 




rif . 2 — A two cylinder ver- 
tical engine with a 860 
degree crank shaft; both 
connecting rods on one 
crank pin. 

Fig. 3 — ^A two throw crank 
shaft for a two cylinder Tor- 
tical engine, crank set 180 

Fig. 1 — A aiiigla throw 
crank shaft. Orank set at 
860 degrees. 

Fig. 4 — ^A two cylinder opposed type of engine with 
crank shaft set 180 degrees. Cylinders are also 
180 degrees apart. 

Fig 7 — ^A two cylinder twin type of en- 
gine used on motorcycles and light cars. 
Note the 860 degree crank. Cylinders 
at 42* angle. 

Fig. 6 — ^A three cylinder vertical type of engine 
with cranks set at 120 degrees. Note No. 2 piston 
is up. No. 8 (right) would be 120 degrees or one- 
third of a revolution; No. 1 would be 120 depees 
or one-third revolution from No. 8. or two-thirds 
from No. 2. 

Fig. 8 — A **V" tjrpe eight cylinder engine. A regu- 
lar 180 degree four cylinder type of crank shaft is 
used with two connecting rods on one crank pin. 

Fig. 6 — ^A four cylinder vertical engine with crank 
shaft set 180 degrees. Note 1 and 4, and 2 and S 
pistons are always in line. 

OHABT NO. 85 — Orank Shafts. 


Two of the usual types of piston rings are shown in chart 34, fig. 8. 
piston rings are made of cast iron of a slightly softer grade than cylinder. 

There are many improved types of piston rings which the manufacturem 
claim will not leak; usually three rings are placed on a piston. The PalVi 
Co. has changed to two rings and claim that for high speed work two is suffi- 
cient whereas, for slow speed work three rings are necessary. 

fThe Crank Shaft. 

The crank shaft throw changes the reciprocating motion of the pistoi 
to the rotary motion necessary to turn the wheels. It rests in bearings that 
hold it in a fixed position, but permit it to revolve. 

The crank pin must be rigidly attached to the crank shaft, and to secure 
this rigidity they are usually made in one piece, solid as in fig. 1, chart 35, 
and is made of chrome nickel steel. 

The crank projects from the crank shaft, and when the shaft revolves, 
the crank makes circles around it. A crank is one of the most conmon 
mechanical devices. The crank pin is that part to which the connecting 
rod fits and is also called the "throw" of the crank. 

A windlass is turned with a crank; a bucket or chain pump is operated 
with a crank; the pedals of a bicycle form cranks. 

In a bicycle^ the crank arms are attached at their inner end to the crank 
ihaft, and to their outer ends the pedals are attached. 

When riding a bicycle, the feet press on the pedals at the ends of the 
erank arms, and make the crank shaft revolve. The feet describe eirelee 
around the crank shaft. Each crank arm and pedal form a crank and there 
is only one arm to a crank. 

In a gasoline engine, two arms are necessary for the reason that the 
cranks are not at the ends of the shaft, there are therefore two arms to each 
erank. (Pig. 1, chart 35.) 

The outer ends of the crank arms are connected by the crank pin. The 
crank pin corresponds to the pedal of a bicycle. A gasoline engine has as 
many cranks as it has cylinders* (see foot note). 

Meaning of Degrees as Used with Crank Shaft. 

The position of a crank on a crank shaft in relation to other cranks on 
the same shaft is expressed in degrees of a circle. 

If a crank shaft has two cranks projecting in opposite directions, as in 
fig. 3, 4 and 6, chart 35, it is called a 180 degree crank shaft. 

If the cranks project from the same side of the shaft, as in figs. 1 and 2 
10 that the crank pins are in line it is called 360 degrees crank shaft. 

In such a case, as shown in fig. 2, chart 35, instead of having two pairs 
of crank arms with a crank pin to each pair, the crank pin may be made 
long enough to hold both connecting rods, and has only one pair of crank 
arms. Both connecting rods drive one crank. This type of engine, however 
ia not used on account of its uneven firing (see chart 53, page 116, for firing 
orders). Engines with crank shafts as shown in figs. 3 and 4 would fire more 

The engine in fig. 4 is called the opposed type of engine. It was formerly 
oaed to a great extent on small cars and is still used to some extent on 
tracks and tractors for heavy work. The cylinders are placed 180 degreee 
•part (see fig. 1, chart 38) ; the crank shaft is also 180 degrees. 

The four cylinder engine, fig. 6, chart 35, employs a 180 degrees crank 
«haft. Note "throws" of crank on cylinder 1 and 2 are 180 degrees apart 
Mid 3 and 4 are 180 degrees apart. 

tS— chart 65 for six cylinder crank shaft explanation. 

*Fif. 2 thowt • two cylinder onfino with on« ersnk. Tbit typ«. however it obsolete. 



riff. 1. A Mild t7p« of cnak shaft — three bear- 
Inff typOi fovr cylinder. 



Flff. 2. A built up typ* of cnak ihaft (teldom 
used). The above is • six cylinder crAnk, with 
four bearings. 


sous TO 


Flff. 4. 

A solid crank shaft, with seven bearings. 

Six eylinder. 


Flff. 12. Typical counterbalanced four* 
throw crankshaft. This method of bal- 
ancing is used on the Steams-Knight. 
Oole and Oakland engines. 


A,. P»iN 

Flff. 6. A regular four cylinder type, 180* 
crank shaft is used on the 8 cylinder **V" type 
of engine. Two connecting rods are placed on 
OAO erank pin; either side by side, or yoked 
(see flg. 7. chart 84). 

If side by side the two cylinders would not be in 
liae but "staggered.** If connecting rods were 
**yoked*' then the cylinders would be in line. 

Fig. 6. In this lUnstrafcioii 
the Idea Is to explain the 
term "degree" used in con- 
nection with erank shafts. 

Any perfect circle is 860*. If the circle Is di- 
vided into quarters, each quarter would be 90*; 
half of the circle 180*; a third 120*. 
Fig. 1. Xote one crank pin — hence 860* crank. 
Fig. 2; from center of one crank pin to center of 
other is half a circle or 180*. 
Fig. S; here we have two pairs of crank pins as 
shown in flg. 2. but on one crank; also 180*. 
ng. 4; end view of a three or six cylinder erank 
shaft. Note crank arms are one-third apart 
or 120*. 

OHABT NO. 80— Crank Slimft Ck>iistniction. 


Therefore, pistons on cylinders 1 and 4 are always up or down together, 
and 2 and 3 are up or down together or in line. 

The eight cylinder "V" type engine would in reality be nothing more 
than two four cylinder engines with cylinders set **V" shape. The angle of 
(flinders usually being 90 degrees or one-half of the 180 degrees of the 
crank shaft. The same four cylinder 180 degrees crank shaft is employed. 
There are two connecting rods to each throw of the crank, which can be 
placed *'8ide by side," fig. 5, page 78 or "yoked," fig. 7, page 76. 

If connecting rods were side by side, then it would be necessary to 
"stagger" cylinders by setting them out of line with each other. 

A three cylinder engine must have a crank shaft wnth the three crank 
pins placed in three positions, or one-third of a revolution apart; this would 
be placing them 120 degrees apart, see fig. 5, chart 35, and fig. 5, chart 52. 

A six cylinder engine would have a crank shaft with six crank pins 
or crank ''throws" placed in thirds, or 120 degrees apart. There would be 
three pairs in line — see fig. 4, page 78 and figs. 4 and 5, page 122. 

*A twelve or twin six cylinder "V" type engine would use the same type 
of six cylinder crank shaft, but with two connecting rods to each crank pin. 
The cylinders would be placed t60 degrees apart or one-half of the 120 degree 
crank shaft. The cylinders would be "staggered" if connecting rods were 
placed "side by side" per fig. 5, page 78. 

The twin cylinder "V" type of engine used on a cycle car and motor- 
cade would use a 360 degree crank or one crank pin, with connecting rods 

Cylinders on this type of engine are usually placed at an angle from 
42 to 46 degrees apart. 

Construction of Crank Shafts. 

There are two kinds of crank shafts, one known as the "solid crank 
shaft" and the other as the "built up crank shaft." (See figs. 1 and 2, 
chart 36.) 

The solid is by far the most used. It is made from one piece of steel,, 
which is forged to shape and then turned up in a lathe, the workmanship 
in many cases being accurate to a ten-thousandth part of an inch. 

The built up crank shaft has each of its parts made separately and 
then fixed strongly together and quite often fitted with ball bearings. 

An advantage of the built up crank is that the crank shaft bearings 
could be fitted with ball bearings. However, built up shafts of this kind 
are not usual, and in the case of powerful engines, only the strongest solid 
crank shafts are ever used. 

The counter balanced crank shaft with counterweights (CW) electri 
cally welded to the crank shaft and an integral part of the crank shaft, as 
illustrated in chart 36 is becoming popular. It permits high speeds to be ob- 
tained without detrimental vibration, and relieves the tendency to "whip- 
ping" of the crank shaft and "slapping" of the pistons, (see fig. 12, chart 36.) 

Cylinders — see chart 37. 

The cylinder of a gasoline engine is made of cast iron or 20 per cent 
lemi-steel, and the water jackets are generally cast in one piece with it. 

In some designs, notably the old Pope-Toledo and 1914 Cadillac, the 
water jackets were formed by surrounding the upper part of the cylinder with 
sheet copper. See fig. 2, chart 37. 

The cylinders of an engine with more than one cylinder, are either cast 
dngly, or in pairs; that is, two cylinders with their water jackets are made 
in one piece. 

•The twelve cylinder engine was formerly referred to as used on motor boats, where 12 cylinders 
WW* placed in a row. The "twin six" refers to cylinders of 6 to a side, placed "V" type. How- 
erer. inacmnch as the 8 cylinder is referred to as an "eight,** although it is also placed 4 cyllndera 
**▼*' t7P0. we will not adhere to this rule entirely. 

tOn tome of the twelve cylinder airplane engines (see page 918), the cylinders are 45 degrees 
■PMt. The Liberty engine cylinders are 45 degrees, see page 934. 


rif. 1. A linfto cyUn- 
Ut with 1 

•round it. 

water jacket cast 



i i 

i 1 

Fig. 2. A liiiglA cjlin- 
der with a eopper water 
jaclcet placed around it. 



Fig. 9. Air cooled laage 
tjpe single eylinder. 



Fig. 4. "T" type of cylinder. Note inlet ports 
on one side and exhaunt ports on other side. Galled 
**T'* type because it is T-thaped. 


Fig. 6. **L" type of eyliiidor. All Talret 
are on one aide. Galled **L" type because it 
is Lr shaped. 

'6rt o^ »^ 

7. Round or **I" 
with detachable 



Z«r ▼•!¥•- 

"singly" is illustrated at (4S). The crank shaft is a 180*" with ive 

Cylinders cast in "pairs** in fig. (4P). Crank ahaft 180* with 
three bearings. 

Cylinders cast "in block" fig. (4E), note a two bearing crank 
shaft. Seldom used, only on very small engines with short crank ahaft. 

A six cylinder engine, with cylinders in "triplets.** (Ag. eT). 
Note the crank shaft appears to be ISO" type, but is divided into 
thirds (see fig. 4. chart 36). 

Cylinders in block with detachable cylinder head is illustrated in 
fig. 4ER). 

Fig. 7. Bound type of cylinder. Valves overhead. Tha uppei 
part with the valve in the head is detachable and is called * Waive in 
the head" type of valve arrangement. This type of cylinder ia ales 
called "I" type. 

CBABT NO. 87— OyUndtr Typ«L 


The portion of the cylinder in which the piston moves should be a true 
eirde, and as smooth as possible. In the better grade of cars the cylinders 
walls are ground to a smooth finish so that there may be as little friction as 
possible. Any roughness of the walls will cause wear, which comes in the 
tonn of cuts and scratches lengthways, that permit the pressure to escape 
iioiind the piston. 

Cylinder heads may be cast solid or with detachable head, see fig. 9, 
page 90 ; also Ford engine, page 783 and insert No. 2. The detachable head is 
gaining in favor. It permits easy access to the valves, and for removing car- 
bon, removing pistons and is good manufacturing practice because it makes 
grinding of cylinders easier. 

Types of Cylinders. 

Cylinders of engines are made in several different shapes and are usually 
made of cast iron. Some of the airplane engine^ have cylinders made of steel. 
See pages 916, 934. 

fThe "T" head type of cylinder is made so that the exhaust valves are 
on one side and the inlet valves are on the other side. Note the "T" shape 
in fig. 4, chart 37. 

fThe ''L" head type of cylinder is made so that the exhaust and inlet 
Ttlves are all on one side of the cylinder. Note the ''L" shape in fig. 5, (if 
tamed up side down). 

fThe ''I" head type of cylinder is made so that the valves are iplaced 
in the top of head of cylinder — ^both valves on one side or opposite, ng 7. 

The "F" head type of cylinder: inlet valve in the head, exhaust valve 
on side. See fig. 6, page 88. 

When an engine has more than one cylinder, the cylinders can be east 
singly or in plain — and can be of either the T, L, round or I head type. 
(See figs. 4, 5 and 7.) Sometimes multiple cylinder engines use all cylinders 
cast singly (4s fig. 6). They can be of the T, L or I head type. 

^Cylinders cast "en-bloc" means that the four cylinders on a four cylin- 
der engine, are all cast in one piece (see fig. 4E). They ean also be of the 
T or L head construction. 

Cylinders on the six cylinder engine (6T) ; can be cast in "triplets,'' 
singly, in pairs or in block. The "L" type is used on the most of the six 
eylLicter engines. They are usually cast in pairs of three cylinders to a 

Cylinders on an eight cylinder "V" type engine are usually cast "in 
block" and are placed 90 degrees apart, and on a twin six cylinder engine, 
00 degrees apart. On a twin ^'Y" cycle car or motorcycle engine, 42 to 45 
degrees. (See chart ^5.) 

The offset cylinder with an offset crank shaft or offset cylinders, as you 
ehoose to say, is represented in fig. 5, chart 38. The line A, which passes 
through the center of the cylinder, is some distance to one side of the line 
B, which passes through the center of the crank shaft. Some of the ad- 
vantages claimed for the offset crank shaft are less liability of a back kick, 
reduced wear on the bearing surface of the cylinder walls, connecting rods 
and crank shaft, less liability of the engine to be stalled, when the car is 
ronning slowly on a high gear, and other construction facilities. The cylin- 
der set central over the crank shaft, as in fig. 4, is the type in general use. 
Cylinders can be placed horizontally, vertically or at an angle, (see chart 

Meaning of Bore and Stroke. 

The stroke is the length or distance the piston travels up and down 
inside of cylinder. 

The bore of a cylinder is its inside diameter. 

*T1m word "en-bloe" U takwx from th« Fruieh. The S. ▲. E. now term this word at "ia-bloek.** 
tSee faidez for "ftdTantafea and diaadvantagea of the T, L and I head eylindert.*' 



rig. 1. Note oyl-.u^fr? 
«r« iUao^ ISO dejr*#* 
apart a v. a ar.' -.r i 'or: 
xoMla! vo*;»ior. T^r=:< '. 
iin "oi'po>e4 o>'..-u^r' 


n»ual m^thwi of »M< 
tUyi c^luta«T« o«e- 

b *» I h oon::#cl.;s^ 
r*sl at* a oTav.K •?% 


S er—i«=» ^- ryU-ir 


0%. :rr*. ■- * -- V^ 

4-' . ♦ 

•* i»' ^-^ i •■- - 



T^ 5 !!♦ ;^s«K -Tl-=- 

i»5 <r '->.'* AA* -rATi 

* A.-. *f;::t.f ».:;.-Xi*-« 

r.JO >* - - " ^•'*-- 

:."' S.-i* . ^# A — 

-zTf.i-T* r,Ni •-» -^ » 

vyr>:^ ^iz:.:^ ?w»:-..vo. 

: .nri ant ^- J »: 

r*Ti :f*« rAZ«* 

F;;. S. Cr^isdCTS at 

.. , - _ r;« a 1^? c?- 
fre< rra=.k if ci«i 
ci a- *:*i: "T" 
:t7«- ari £7:ir£er» 
are T-»^*i cr«-i.alf 
:f :^:a. rr K irffrces 

T-f :r%Tt »iif: c- a 

i<c-^: ;r*r.k arl cyliad^ri are placed at an 


^>rr«>«% tMafc'> r%r»' 





r^. 6. ••T" head 
trye of cyLcder v:th 
f^sazi: sir.ifoM on 
r^# fide az:d intake 
c^r:fc!d oa tLe op- 
;-:«i:e a:ie. 

'7':*- ii< extaaat aod 
ir>: r:.arifoU vooM 
r«.-ii i* crs one aide 
:r SI* "rmlre aide. 

^t'it: &ad Sxh^ast ICmifoldfl. 

SxlaxK yaTlTrM csBstzvetiOB: 
A ^ a fiol iM;i»c cf axhavst om- 
.-.z ::r a 1 re 4 rrliader Ttrtical 

' B:" a s^s; je aazifrld ia vkieh 
1^ --sirr-.cra; jipe fr;a eark cyl- 

■,*.-4':':;c zLaLi^iZ ■ CI-"" Is t^^ii 
=ji fiOi :i-t .-^L^rtur ix^* is siaie 
»:x^.:.-ri:j iarf* " '^M wrea lie 

a .7 :j :««» :1«2. tra: is ikt ej:- 
-Tt-fr a: ii« rxlT-t m tS*; lieire i* 

• V - v-.V— ^. 

r " i^ass'^^ 



<* *. V * '^^ > 

^" >. 


N » »» V* 

-•ivi a-t 7 ?•» I ai£ : izT ._. 
mi'LJt rx33Li*iT% are frcTr*^ :- 
'ct "»itr«a* ZX'^ ar» »f7,ara:e 

:.-c r7":a«i-fn I asii 4 T":j ^v.-rii 
is*: :k: i mr^iT n. 'u.a: rr"_i'E«r» C 
iT-i ? !■*"•«* «T7Cii»ai pin.«<xtT-s:T 
i.ri ^i* ;a-f it:it 3i rKTia^'f »^ ta<- 
■r.j: ;■».'«* J.: ^-f fxziauc iif ti* ;▼:. 
? 3i «t3:e tfESK' %i ^K ir 

1-3 z I. &T>i I azii 4 Tla :» :<ai 

r^.**-7-i ■:—•«. 3 IMC -ft iX^uitin 

- "- *■- :a-<" ^vv-ji^ rhj r'"-a;"«^ s "U'« aas«. 

■.>■ / t:a*i i T:a-= . j.ii jx "»: .ri zm fUdcxac ?i7»f 

j^i. *».? :i--f irt.r a.'r a3«t «-::iiajiR >^-{« i^- 
■ ■^* -■ ::»T .-.. T ■.» 1 fli»p« IC-J|ir« r « rati CI 

« ■ » ■ -»■• ^ s : * :«*■ : j» "MMWi-e v "s-jjlm 11- rr-; 

. ^ "^= ;-7.-e»-T» /. A *?.s. r SKX 'y^Ll-j 

. -* : A :c 2: :3^r -'a-r »t^~ v «-• «!*:«. 

.•;:: - t^ -^ .: ■ : ;-> s ^: =-.. . i^ i.rr* r^rai 

:-.•:- .-...■:M7v.-r zx.4«- i.ri -!.—.> a. ziii 


•L r": > » 

y^i^^^.-'.ira a 

,^ux^v^\^ *s K>^v.v^ K:. 

ni i.:^' <w jvwit 


Square stroke; when the piston travel in a cylinder has the same length 
as the bore in diameter, then it is called a square stroke and bore. 

fLong stroke: when the piston travel is much more than the bore di- 
ameter, ^en it is called a loag stroke. For instance, a piston 4x4 inches is 
called ''square stroke." A cylinder whose bore is, say, 4 inches and the 
stroke is 5V^ inches, this would be called a "long stroke." 

The valve chamber is that part surrounding the valve. The valve port 
is the opening for the intake or outlet of gas. 

The combustion chamber is the inside upper portion of cylinder, above 
piston, when the piston is at the top of its stroke. 

**Inlet Manifold and Pipe— see chart 38. 

The inlet manifold is the part which connects to the inlet port open- 
ings in cylinders, from carburetor. If there is only one connection to cylin- 
der, as on a single cylinder engine, then it is called an inlet pipe. 

When the valves are all placed on one side of the engine, as in the *'L" 
head type of cylinder, then the inlet and exhaust manifold are both on the 
same side of the cylinder. 

When the inlet valves are on one side and the exhaust valves on the 
other side, as in a ''T" head cylinder, then the inlet manifold is generally 
on one side and the exhaust manifold on the other side. 

In order that there may be as Utile resistance as possible to the flow of the 
mixture, this manifold should be as straight as the position of the earburetor wiU 
permit. There should be no sharp angle bends, the bends being as flat and easy as 
possible and the distance from carburetor to inlet ports as short as possible to prevent 

When more than one cylinder is suppUed from one carburetor, the distance from 
the carburetor to each valve should be the same. The inside of the inlet manifold 
must be smooth and clear inside so that there is no obstruction offered to the flew of gas. 

In those marked '* incorrect" (chart 38;, the distance from the carburetor to the 
inlet valves are not equal, and consequently the valves nearest the carburetor will get 
more of the mixture than those farther away. 

In the arrangement marked '* correct," the, distances are equal, and consequently 
the valves get equal quantities of mixture, and the engine wUl run more evenly than if 
the cylinders received different amounts. 

Exhaust Manifold Construction. 
In chart 38 exaggerated and simplified illustrations are shown in order 
to give the reader an idea of the different methods. 

Sharp bends in the exhaust pipe cause back pressure, and should be 
avoided. Dirt in the pipe or muffler has the same effect, and this should be 
gpiarded against. 

Exhaust Pipe and Muffler. 

The exhaust pipe leads from the exhaust manifold to the muffler. If 
engine is an eight or twelve **V" type, there are usually two exhaust pipes 
and two mufflers. 

In order that the exhaust manifold may be cooled as rapidly as possible, 
the exhaust manifold and pipe, connecting the exhaust valve chamber to the 
muffler, is exposed to the air. 

The connection from exhaust manifold to exhaust pipe is usually made 
with a flange connection with asbestos packing between. 

'''The muffler and exhaust pipe should be made so that there is as little 
back pressure as possible. Back pressure is caused by anything that prevents 
the free escape of the gas therefore sharp bends should be avoided, otherwise 
the incoming fresh mixture becomes mixed with that part of the burned gas 
left from the previous charge, and the power of the engine is cut down ac- 
cordingly. The muffler is explained in chart 39. 

t8«t p«ge 631 for "advantages and disadvantages of long and short stroke." 
**Tbe modem inlat manifold is water jacketed or gas heated as per pages 157 and 164. 


% *Ji 



- ••. r.iviZ 

• • • r:l.r»te 
L.- 5}. A 

• . .\:>r of 

.7« - .-^ 


■S rod. 8 — Oonaectine rod i]iiia«, or 
•Coiui^eline rod boarins cap. U — 
«t»d bearing c«p duU, V — Oonnecting 
^nr — PUton pin biulilDf« X — Pi«loa 



Tig. 2: Oyllnder liesd U d«ticli- 
«blfl with YSilvea. Oylmdcn 
ftepsrate» therefore a head ia aeo- 
esMry for e«ch cylinder. If cylindar* 
were *'eo-bloc" ip^t page B0'4EB}, 
iben there would be but one head. 
A^ — ^Valve ftprmg cap nat, B— Tal^re 
aprioff «ap lock nut. — YalT« 
tprine. 1>— Yalre ■tern guid*. S 
— VnRe. 

* dtiliie bottom iiiie up, ahowiiif main bearinfft 
in ita bearine There are Ave maio bearingl 
_ _ r enfinep usual oumber !■ three. 1. 2, 8* 4, 6 
iflbtarinca. A — Bearing cap nuta. fi — Bearing eaps. 

End ', iue bolow- — showing 

the gtiar^. _. 1, meaiuree 4 mchM. 

gear A uiea«ures S inchei« A — ii the 
<*eiD ibaft gear (all valves on one 
tide), and overhead, mechanically op- 

E — Drive geer on crank ahaft. D — 
Idler gear between drive gear and 
cear operating the magneto. B — Mag 
neto g(^a^, 

Th« cam Bb&rt g«*r runt onahall 

the ipeed ef the craok thaft. 

The magneto gear rum ai 
a« crank shaft. 

It* ild«. Exhautt and inlet vaWei are both mechanically operated and are overhead type, A eyttem oi 
4 ro«k«r arms for both inlet and exhaoat, 8ee page BB for explanation of variona typea of velvet, 
•^raler inantfold clamp bolt, B — water manifold clamp. — ontiide water coonectioo, D — oil pump and igoi- 
lltC I»»i"»* E — oil pump, F — oil pump tprlag catch, G- — water pump. H — intake water manifold, I — ^rettun 
■SBifold, J — ignition timer ^ K — oil pipe, Lr— hoie clamp, M — front cam abaft bearing acrew, N — valve lift«r* 
h red adjuitment, P— valve puah rod, Q — center cam sfieft bearing acrew, R— rear cam shaft bearing lerew, 
■ eaa abaft bearing cap, T — water pump grease cup. 

O* €1 — Study of « 4 Oyllnder Unit Power Pl&nt: 
i vmlvea. Valveg are ground in head; Cylinders; 

Valves; overhead; Oyliiider head, detachable 
*I** or round head type east singly, modem 
itlce is to cast in pairs for 4 cylinders^ and in pairs of three for 6 cylinder engineB. Note the dif - 
aee i^ the *' valve in head^' and other ^* overhead valve '^ eyatems m chart 42^ page 00. 
40 on page BG — by error.) 



*.: T-n St iif ^ T*tttr^ %:rf rmr r^iu la stir: kjl'^ 

5^ * 

C^3xa. razx Sixf^ inrmiit i^ int ajt 


Valve Caps. 
Where valves are on the side and the head cast integral with cylinders, 
valve caps are screwed over the valves in the cylinder (see figs. 7, 8, page 90, 
also chart 32). By removing these caps the valves can be lifted from their seat 
and ground. There are two valve caps to each cylinder; an inlet valve cap 
and an exhaust valve cap. 

Compression or Belief Cocks. 

Consist of small pet cocks screwed into the exhaust valve caps. By open- 
ing when the engine is running, it is possible to see if any of the cylinders 
are missing fire. A fiame will shoot out if firing. If mixture is right the 
flame will have a blueish color. They are also used for injecting gasoline in 
winter when engine is cold and hard to start — see chart 32, page 64. The 
8. A. B. now term this a ** priming cup." 

*Cams and Cam Shaft — see chart 40. 

A cam is a device that produces intermittent motion. When an object 
is in motion part of the time and at rest between motions, its action is said 
to be ** intermittent." A cam may best be described as a wheel with a hump 
or nose on one side (figs. 1 and 2), or in other words, it is a piece of metal re- 
volving with a shaft, part of its circumference being farther from the shaft 
than the rest. The part of the cam that projects is called the nose. Any- 
thmg resting against the cam will be moved only when the nose comes around 
to it; otherwise it remains stationary. 

For a four cylinder engine, four cams on the inlet cam shaft are shown 
in chart 40, fig. 7. Four more cams on an exhaust cam shaft are provided on 
the opposite side of this engine, because it has **T" head cylinders. The 
cams are divided in four positions on the cam shafts, and are made in one 
piece or integral with the cam shaft. If the cylinder is **L" type then all 
cams would be on the one cam shaft — see fig. 9, chart 40. 

tFor each cylinder there is one inlet cam and one exhaust cam. The ex- 
haust cam usually has a broader nose because it must hold the valve open 

The cam shaft, also called the ''secondary" or ''half time shaft," has a 
cog wheel or gear, called a •timing gear, on one end, which meshes with the 
drive shaft gear on the crank shaft. 

When the crank shaft revolves, the drive gear on the crank shaft drives 
the timing gears, which drive the cam shaft and thereby rotate the cams. 

The nose of the cam raises a valve lifter or tappet, which plunges 
against the end of the valves and raise tLem from their seat. When the nose 
of the cam is under the roller or valve lifter, the valve is held open ; the valve 
is closed after the nose passes, by the action of a strong spring, (see page 92.) 

The valve stem being held in a valve guide, cannot move in any direction 
but up and down. Thus the steady rotary motion of the cam is changed to 
the intermittent motion of the valve. 

As has been shown on four cycle engines, each valve opens only once 
while the crank shaft makes two revolutions. Therefore the cam shaft should 
revolve only once while the crank shaft revolves twice. 

jiTiming Gears and Silent Chains. 
If two gears running together (or in other words, in "mesh"), have the 
same number of teeth they will make the same number of revolutions. 

*Por getting cams, see valve timing instruction No. 9. Also Dyke's 4 cylinder engine model. 
tSpecial racing type engines, as the Stutz. page 109, hnve two inlet and two exhaust valves, and 
ti many cama. The White also. Thia is termed "dual valves," see page 109 and 927. 
tPor "adjustment of timing gears." "silent chains." etc.. see index. 


£ig. 1 — Poppet Type 
of Valve; 

. so nfimed be- 
oAiite the vftlve pope 
up and down. There 
•re two valves to each 
cylinder; an inlet and 
an exhaust valve. This 
tjpe of cylinder is a 
* 'T' ' head, therefore 
valves are on opposite 
sides and mechanically 



"IN" means 
inlet, and "EX" 


Fig. 2— T h • 
Botary Y a 1 ▼ o — 
See chart 70. 

Hg. 3 — T b a 
Sleetra Type of 
Valve; there aro 
two sleeves with 
openings at up- 
per end. When 
these opening! 
are together, the 
fresh gas is ad- 
mitted or burnt 
gas discharged. 
See pages 139 
and 140. 


Fig. 4 — ^AntomaUe Inlet 
Valve. Suction of piston 
draws the valve open againat 
the tension of apring. Ex- 
haust valve mechanically 


Fig. 6 — Cylinders are "L" shaped, all valves 
on one side. Note the four inlet and four ex- 
haust valves on four cylinders. These vahres 
are the "poppet" type and are mechanically 

To remove valves; there are valve caps over 
each valve. 

Fig. 7. — Overhead 
mechanically operated 
inlet and exhaust 

Fig. 10. — The Dae- 
•enberg principle of 
operating valvea from 
the aide. There are 2 
inlet and 2 exhauat 
valves per cylinder. 


Fig. 6. — Overhead mechanically 
operated inlet valve and side 
mechanically operated exhaust 
valve on *'P" head type of cylin- 
der. The inlet valve in this instance 
would be "Cage" type (fig. 4. 
page 90). The cage with valve 
IS screwed into cylinder head. 

To remove the inlet valve the 
caRre with valve is screwed out. 

To remove ezhantt valve a valve 
cap over the valve is removed. 

Valve Operation and Location. 
Valves are operated either mechanically or automatio- 
ally. The inlet valves can be of the autoxnatie type (fig. 
4), but is seldom used for automobile work. It is used 
to some extent on the single cylinder motoreycle engine 
and quite often on light duty stationary engines. 

The exhaust valve is always mechanically operated, in 

fact it cpuld not be operated automatically by suetion. 

There are different arrangements for operating the 
valves mechanically as shown in illustrations and on page 


The sleeve and rotary valve would be classed as me- 
chanically operated. 

The location of the inlet and ezhanst valve can both 

be on the side, per fig. 5, or inlet overhead and exhaust 
on the side, per ng. 6, or both inlet and exhaust overhead, 
per fig. 7. See also, page 90. 

OHABT NO. 43 — ^Valves; Types, Oonstmction and Operation. See also, page 90. 
Chart 41 on page 85. 



If the dxivon gear has twice as many teeth as the drive gear, it will re- 
Tolve only once wlule the other reyolyes twice. This is called a ''two-to-one" 
or ''half time" gear. 

Because the cam shaft must revolve only once while the crank shaft re- 
volves twice, the cam shaft gear has twice as many teeth as the crank shaft 
drive gear. See chart 40, fig. 3, for an example — and below. 

The cam shaft revolves in opposite direction to crank shaft when driven 
1^ gears without an idler and same direction when driven by a silent chain 
or an idler. 

m ^*- 

The wide face helical gear is most popular for the timing gears. Special 
material as fabroil, micarta and other compressed materials are used by 
many as material for making gears which are silent. Drop forged gears are 
also used to a great extent. Also steel for the crank shaft gear and cast iron 
for the cam gear. 

The silent chain for driving the generator is quite popular and it is also 
being used to a certain extent for driving the cam shaft. The object is to 
obtain quieter running. This type of chain must not be confused with the 
ordinary roller type as used on chain driven trucks. The silent chain is more 
positive in action, otherwise the timing would be thrown out of adjustment.. 
The teeth on a sprocket used for a silent chain are very close together and 
aeenrately made. 

Any undue slack in the chain can be taken up by sliding the magneto or 
generator shaft outwards (see fig. 3). This chain is self-adjusting for pitch. 

Engine Valves. 

Purpose of valves: There are ftwo valves to all four cycle gasoline en- 
gines ; an inlet valve and an exhaust valve. By referring to charts 29 and 26 
Uie location and purpose of the valves will be understood. 

Types of valves: There are three types in general use; the "poppet," 
*' sleeve" and ''rotary" (see chart 43). The poppet type being used almost 

The inlet valve admits fresh gas to the cylinder. As fresh gas is going 
into the cylinder during only one stroke of every four, the inlet valve is 
opened during only one stroke of every four, or in other words, during one 
stroke of every two revolutions of the crank. 

The exhaust valve permits the burned and useless gas to escape. It is 
opened and held open by a cam on the cam shaft. This is termed "me- 
ehanically" operated. 

DIrtctioa of tnT«l of fly wheal and cun gears: When ttanding behind » fly wheel on an auto- 
■•Ikfle OBciao it tnma to the loft, whereat standing in front of engine it iurna to the right. AUo 
■He the diroetion of rotation of cam gears, fig. 2. chart 29. 

tUMfo ore a few onginos luing fonr Talres for each cylinder, see page 109. flg. 8. 


-■^ I cs«ea»«»o vft4VES - ^n a ^olid cyhkoEr head 

b\.jT opposite 

mnvi OH 

RGB- CAGE REMOVIO Anrtjutthwo 


^^De ALLVAtV¥5 

cm ONE SlOe CVtrNCHEH H£ftO iMTeRGlilU. 


tAfH W^O WfcM Si 

CAM -SM^PT- Sft P»« i3l! 

n a 6A' OCTMC mable HE^VD' 

1 H t 3< a£ - Of L HEAD DtTftTC "■^ S 

Valve construction: There are two different valve constructions in general use; ( 
OYerhead; (2) the side. 

The OYerhead valve may be divided into two types; (1) the overhead valve in a d 
able cylinder head and a unit of the head; (2) the overhead valve in a cage and a se 
unit from the head. 

The operation of the overhead valve may be divided into two methods; (1) by pus] 
per figs. 1 and 2; (2) by an ^overhead cam shaft, per fi^. 5 and 6. 

The side valve construction may be divided into two constructions (1) where inlet 
is located in cylinder head on one side and exhaust valves on the other or opposite, ; 
fig* 7; (2) where all valves are on one side. The operation of the side valve is invaria 
a cam and tappet lifting the valve. 

Cylinder head on side valve cylinders may be cast integral with body of cylinder t 
figs. 7 and 8 or detachable as per fig. 9. 

A combination overhead and side valve arrangemeut is shown in fig. 4. This t; 
called the **P" typo. The head could be detachable with valve in the head, or cage typ 
head integral with cylinder. With this type, the usual method is to operate the inlet 
head, and the exhaust from the side, both being operated from a single cam shaft. 

okikBTlNro. 4a^Vaive bonsMiotlon and Belation of Valves to Cylinder] Ohart No. 44 is 

*TJb# OT«rb«ad can-ihaft with overhoad valvet is the popular method used on airplane engines — see pages £ 



Muchanically operated valves are opened and held open by means of cams 
and closed by means of a strong spring, (see chart 44.) The exhaust valve is 
always mechanically operated. 

Inlet valves are generally mechanically operated, but some of the old and 
motorcycle type of engines have valves of the ** automatic" type. 

Automatic operated valve is held against its seat by a light spring— see 
ekart 43, fig. 4. During the suction stroke, the sucking action of the piston 
as it travels downward in the cylinder, draws the valve open. At the end of 
the suction stroke, when the suction ceases, the spring forces the valve disc 
back to its seat, and the gas is prevented from escaping through the valve. 

It must be understood that the valves of a gasoline engine always open 
inward. Thus the pressure from the power and compression strokes tends to 
keep them firmly on their seats. 

Usually inlet and exhaust valves are made the same size. Some manu- 
&etnrers are making the inlet larger, for instance the Sterling engine has 1% 
inek inlet valves and 1^^ inch exhaust valves. The lift of a valve is the 
height it is raised from its seat by the cam. 

Valve Operation and Location. 

The "mechanically" operated "poppet" type valve is the type in general 
use, therefore we shall confine our attention to this type. 

Valves are operated; or opened by the intermittent motion of a cam and 
closed by a strong spring, as explained under **cams" on page 87. 

**The cam shaft may be overhead or on the side, as per page 90. 

The location of the valves are overhead or on the side as per page 90, or a 
mnbination as per fig. 4, page 90, which is termed the **F" type. 

Overhead operated valves may be in a detachable head of cylinder or in 
cages as per figures 1, 2, 5 and 6, page 90. 

Side operated valves may be 
placed all on one side, or opposite 
sides of cylinders. When on op- 
posite sides, two cam shafts are 
necessary; one on each side — see 
fig. 7, page 90. When all valves 
are on one side or overhead; one 
cam shaft is sufficient — see figs. 8, 
1, 2, 4, 5 and 9, page 90. 

fTo grind valves in an overhead 
valve engine with detachable head, 

in the head (fig. 6A, page 90) — un- 

ninstration at top. 
The one at bottom, 

-V. On •*L'* bead type 

I^A- of cylinders, all inlet 
^ and exhaust valves 
are on one side, but 
they do not run con* 
secutively. Owing to 
the fact that the exhaust 
manifold must connect with 
all exhaust valves and inlet 
manifold must connect with 
all inlet valves; the valves 
are usually arranged as in 
illustrations above. Note 
the exhaust is always on 
the outside next to the water 
is that of a 6 cylinder engine. 
4 cylinder. 

'cage" type valves, 

the head is removed, and valves are ground 
less valves are in a cage. 

To grind valves in an overhead valve engine with 
the valve is ground in the **cage'' as per fig. 3, page 90. 

To grind valves on a side valve engine, the valve caps are removed if head 
is integral with cylinder as per figs. 7 and 8. If head is detachable as per 
figure 9, then head is removed but valves are ground in their seats in the cyl- 

Although the valves vary in location and methods of operation, the prin- 
ciple or purpose remains the same ; the inlet to admit fresh gas, and the ex- 
haust valve opens at the correct time to expel the burned gas. 

*ValvM are made of cast iron electrically welded to a steel stem. They are alto made of 
iickcl st««l or Tungsten steel. The latter being considered best. 

t8e« Index for "valve grinding." **See foot note page 90. ttThe apark plugs (S) are ufnally 
Ibced over inlet valves, per page 121. 



Valve Parts. 

A * 'poppet" tsrpe valve lias three parts; a 
**head;*' a **8tem," which forms the moving 
part, and a ** valve face" which seats into a 
* * valve seat. ' * This valve face is beveled and is 
perfectly round. When seated, it must fit the 

T ■»' o methods of 
eating valve-lifter, 
note valve and 

other bushed. 

valve seat perfectly tight, otherwise during com- 
pression stroke the gas would leak, and on power 
stroke, a loss of power would result, by the valve 
leaking at the seat. Therefore it is ground to 
this seat. 

The valve^spriiig holds the valve tight in its 
seat and must have sufficient tension at all 
times (see pase 635). If too strong, the valve 
will close with more noise. If too weak valve 
will not seat properly. The exhaust valve spring 
usually weakens first on account of greater heat. 

The ▼alve-fprlng-rotainer-and-lock, formerly called 
valve ipring waiher, U placed at bottom of spring and 
held in place by a two part lock. Formerly a "key" 
pasted through a hole in the valve stem (see page 630, 
flff. 1). 

Valve-face is the beveled part of valve head. 
The valve-seat is the part of cylinder head in 
which valve face is placed. The valve face and 
seat can be ** conical" or ''flat.'' They are 
usually conical as per fig. 2 above, and fig. 7, 
page 94. Valve head is upper part of valve stem. 

Valve-stem is the stem part of valve head. 

The stem of a mechanically operated valve on "L" 
or "T" head cylinder of the "side valve" principle, 
usually extends about half way down to the cam shaft. 
A valve-lifter then lifts the valve stem by action of a 
nose on cam as cam revolves. (See paj^e 87.) To %e\ 
this cam, to raise valve at the proper time, is called 
"valve timing," 

On engines with overhead-valves, there is a 
rod. called the "push rod," between valve lifter 
and rocker arm, see fig. 4, page 94. 

Valve-clearance also called ''air-gap," is the 
distance between lower part of valve stem and 

valve lifter. On the push rod type, it is usually 
between rocker arm and end of valve stem. This 
distance is regulated by an adjusting nut. 

Valve-lifter, also called '* valve plunger," 
"valve tappet" and other names, is the part 
placed between valve stem and cam. The top 
part has an adjustable screw which can be 
slightly raised or lowered to get correct valve 

The bottom of this valve lifter is sometimes fitted 
with a "roller." per fig. 3, page 94. The "mushroom" 
type, fig. 2 above, and figs. 1 and 2, page 94 is the 
type used most. 

A valve-rocker — ^npper, is used on overhead 
valves, also called * * rocker arm ; " a valve-rocker 
— slower, is the principle shown in fig. 3. It is 
also called a **side tappet lifter." The latter 
is seldom used. 

A valve-stem-guide holds the part through 
which the valve stem passes. Sometimes it is 
''bushed" as shown in fig. 2, also see page 634, 
^g. 7. Quite often it is plain as per fig. 3. 

A valve-lifter-gnlde (also called ''plunger'' 
and "tappet" guide), is shown in fig. 2, which 
is fitted with a bushing and can be renewed 
when worn. It is bolted, sometimes screwed to 
crank case (see also page 54). In fig. 3, a plain 
guide is shown. 

Enclosed valves are where a cover fits over 
valves (fig. 2). This deadens the noise of lifter 
striking valve stem and keeps out dust. Also 
see page 121. 

Although valves may be placed overhead, or 
a combination, as overhead and on the side — the 

principle of operation is very much the same, 
(see page 90.) 

**Pnrpose of Valve Grinding. 
The exhaust valve Is surrounded by flame 
when open, and will become "pitted" in time, 
as per (fig. 4). 

The exhaust 
valve requires 
more grinding 
than the inlet 
valve because the 
hot gases pass out 
between the valve 
seat and valve 
face when valve valve i 
i s raised. When 
the valve is open- 
ed, there must be 
sufficient space to 
let the burnt gas 
pass freely. 

The inlet valve, admitting gas instead of 
ejecting a flame does not pit as badly as the 
exhaust valve. 

In a perfect seated valve, the valve face and 
seat are smooth and even, with dull gray sur- 
face. A pitted valve is rough, uneven, and full 
of tinv holes, and cannot come to a tight seat. 
Therefore valve must be ground. 

The process of grinding a valve is the placins 
of a grinding paste between the valve face and 
the scat, and the revolving of the valve until 
the roughness is worn down. See index for 
"valve grinding" and "valve re-seating." 

*The "tulip" shaped valve is another type of inlet valve scat but now seldom used — see page 128. 
**Se« first paragraph this page and pages 628 to 632. *See foot note page 94 for valve material 












ng. 1. Sxample; luppoie we Uke a tj wheel and divide Ite drcnniferenoe Into 360 e«ail paxle; 

eedi part would be a degree— expressed with e ■mell "o" at 860*. 

In fact, anj perfect circle een be divided in degrees. The crank sheft revoWes in e circle, therefore 

we win designate the travel of the crank shaft in degrees. 

Om half of the drde would be 180*, which would represent a stroke of the piston, or a half revolutioB 

ef the crank. One quarter of the circle would be 00*, one third of the circle would be 120*. 

An J circle, or say, travel of the crank pin, would represent 860* when it made a complete circle 

•r revolution. 

Fig. 2. Bzample: piston has traveled down from upper dead center, one quarter of the circle or 

oae-half of a stroke; crank pin and flj wheel have turned 00*. 

Fig. S. Bzample; piston has traveled from top dead center to bottom of stroke, or one half of a 
roTOlutlon; fly wheel and crank pin hare traveled 180*. 

Fig. d« Bzample; piston has traveled up from bottom, one-half of a stroke; crank pin and flj wheel 

have traveled one quarter of a circle from bottom or 90* from to D. In all, the crank pin and flj 

wheel have traveled from A to D, three quarters of a revolution or 270*. 

Fig. S. Bzample; the piston has made two strokes, one down and one up, therefore crank pin and flj 

wheel have made a complete revolution or traveled 860* in all. 

Tie Idea is to learn that the crank pin travels In a circle and the fl/ wheel travels In a drde, and a 

reftttakloB Is a complete drde, and a complete circle is 860*. 

Tie piston travds in strokes, each stroke representing a half revolution of crank. 

n wa spaced off S60 marks, equal distance apart, on any clrde, then each mark would be called a 

degree. In flg. 1, we have spaced off the marks as 5 degrees each. 

■ew we can dlride each degree Into say, sixty equal distances apart and call each part or mark, a 


We oenld go stUl farther, and divide each minute into sixty equal distances apart and call each part 

or flsark, a * 'second." 

A mlmte is usually expressed with a single mark after the figure, as, 25'. 

A second with two marks, as, 26". 

**firlt; express, ten degrees, six minutes and five seconds. It would be as follows; 10* 6' 6". 

■ela— To And the drenmference of a fly wheel; multiply the diameter in inches by 8.1416. If the 
eircamference is then divided by 860, the distance or portion of the fly wheel circumference equivalent 
to one degree may be ascertained. 

OBABT KO. 45— Explanation of tlie Maanlng of Degrees, Minutes and Seconds. Note; Oramk 
fltefts OB Engines usually turn to the right — (When in front). On above illustrations we art 
Mpposed to be standing in the rear of fly wheels turning it to the left which would eanse erank 
iwt to turn to the right (from front). 
Qhsrt 4a ea page 88. 





LOOSS/V \> - fCCiOSiO ^ 
LOCt^NUT ^^^-^X, 

AmscRi^ M< 










1-2. — Mushroom type of valve lifter. 

S. — ^Roller type valve lifter. 
Note in Fig. 1; valve Just lUrting to lift. 
8 and 8, ¥alve Just doaed. 

Ezhaoat'camfl usually have broader note than in- 
lets, beeauae the exhaust valve remains open longer. 

f<t*Ct tifftt 

tfi55 Of 7 Hi 

if0fr0 ^/vff*f ^»'Mr ^-/t- 

Fig. 4. Valve-clearance on valves-in-the- 
head is measured between end of rocker- 
arm and top end of valve, as above. Adjust- 
ment is made on lower part of valve rod 
on the Dorris, as above. On the Marmon, 
adjustment is at the top of rod as per J. 
flg. 1, page 90. On the Buick. at the top, 
per page 109. 

Fig. 7.— Note the "ilat" and '*conlcal" type 
of Talve. It is said, the flat valve gives greater 
opening for the same valv% lift and has greater poasi- 
bilities for high speed work, however, it is seldom 

*Valve Clearance Adjostment. 

This subject is explained on page 110. An ex- 
ample of adjusting the valve clearance on a "aide 
valve" engine will be given here. 

Valve clearance means the distance between the 
end of valve and the end of tappet or plunger which 
lifts it. 

When an engine becomes noisy and a cUeklng 
noise is heard, the trouble is likely in the valve 
ends having worn or the adjustment nut become 

This adjnstment can usually be made by icrew- 
ing up on the adjustment screw (fig. 5) and then 
locking the position with lock nut. 

The clearance is necessary in order that the valve 
seats properly and should usually be from .008 to 
.005 of an inch when engine ts cold. 

The adjustment ahonld always be made— after 
the valves of an engine are ground or when cheek* 
ing the valve timing — see also, pages 635, 785. 

The procedore to adjust is as follows: turn fly wheel of 
engine over until the other tappet and valve in the same 
cylinder is up as far as it will go, or the valve wide open. 
The first valve will then be closed. As previously stated 
there should be from .003 to .005 of an inch between the 
head of the tappet screw and the end of the valve stem. 

If it is found that the clearance is not right, loosen the 
lock nut on the tappet screw and turn the screw up or 
down as may be required to obtain the correct clearance. 

It la best to use a 
"thickness gauge" (page 
700), but if a gauge 
is not obtainable a piece 
of newspaper will serve 
as a gauge, a sheet of 
ordinary newspaper is 
between .002 and .003 
of an inch in thickness. 
After the tappet screw' is 
adjusted so that the 
clearance is correct, 
tighten the lock nut. 

"Back lash'* or lost mo- 
tion In the cam shaft 
driving gears should be 
taken up in direction of 
rotation when clearance 
is adjusted. 

A noisy Talve tappet, 
caused from wear, and 
where no adjustment la 
provided, can be, in 
some instances repaired 
by placing fibre or steel 
washers under or over 
valve ends. 

To adjust valve clear- 
ance on overhead valve 
engines — see fig. 1 on 
page 109. 

The opening and dos- 
ing time of the valve 
is not when the lifter 
begins to rise or comes 
to rest but when it 
makes or leaves contact. 


s Tapp«t 
Afljusting Scre^v 

Grinding and Reseating Valves. 

If valvea become pitted and leak, they need re-grinding. If warped 
or shoulders form in the seat, then the seat and valve ought to be refaced. 
Bee index "Grinding Valvea." "Reseating Valves." 

Fig. 5. — Type of Talves 
fide of "L" head 
clearance is adjusted aa ahowi^ 
in illustration. (Hudsen aiz.> 

GHABT NO. 44 — Valve Clearance. Valves and Cams. See repair subject and index for vaE"^" 
grinding. See page 542 for valve timing of different engines. 
/Chart 48 on page 100). *8ee pages 631. 684 and 680. 



* VALVE TIMING: Valve Clearance. Meaning of Degrees. 
Periods of Travel of Cam during the Four Strokes. Exam- 
ples of Valve Timing. 

Before the reader can thoroughly master the subject of valve timing he 
must first learn the four cycle principle as explained on page 57 to 59, aa it is 
with this principle we will deal. In addition to the above, the meaning of 
degrees as explained in chart 45, and the relation of the valve cam speed to 
the engine crank shaft speed and the importance of valve clearance adjust- 
ment must be thoroughly understood. 

Valve Clearance and Lift of Valve. 
If no space was left between the end of valve stem and the cam,* even 
very slight wear of the stem and seat would prevent the valve from closing 
properly. Furtherfore there must be some cognizance taken of the expan- 
sion due to heat. As the stem expands, it gets longer so if no clearance were 
provided the stem would rest against tappet and be unable to seat properly. 

** Valve clearance, also called "air gap" space, is the space between the 
end of valve stem and the lifter or plunger. The width of this air gap 
ranges from the thickness of tissue paper to 1/16 of an inch. The average 
gap is somewhere about or slightly less than postal card thickness (see in- 
dex; Standard Adjustments of Leading Cars). 

Some manufacturers give about 1/1000 of an inch less space to the inlet 
than the exhaust, because the exhaust valve stem lengthens more; due to 
greater heating. For instance, Hudson gives .004 of an inch, to the *'air 
space" on the inlet valve and .006 to the exhaust. 

The adjustment should always be made with engine cold and after the 
valves are ground, as the grinding may slightly lower valve. 

The valve lift: the inlet cam has a sharp nose. The exhaust cam has 
a broader nose, because it must hold the valve open longer. The height 
of the nose less the air gap, regulates the lift. 

The average lift of either exhaust or inlet is approximately, 3/8 or 9/32 
of an inch. It is thus evident that if the air gap is 3/8 or 9/32 inch too. large, 
the valve will not open at all. 

Now if the air gap (3/8 inch) is slightly decreased, the valve will lift 
very slightly and stay open but a few degrees. If the air gap is again 
slightly decreased, the valve will open sooner, raise higher and close later. 
This process can be repeated until there is no air gap left. 

Therefore, suppose an engine was designed to have 1/16 inch air gap 
Mid there was no air gap at all; the valves would open possibly 50° too 
soon, raise 1/16 inch higher than intended and close 50° too late. 

As to wear of end of valve stem or tappet; it is apparent that as the wear 
increases, the space or air gap increases and valves will have less lift, open 
J*te and close early and become more noisy. All of which will aflfect the 
power of engine. 

*For TalTe grinding and other repairs, tee "repairing instmction." 

The stndy of TaWe timing will be timplifled if the reader will refer to Dyke's four and aix 
2'nder engine modeU. Valve tlxnlni; of leading automobile engines given in "Standard Adjustment 
*f Leading Oars/* see index. A, table for conTerting degrees into inches, and fractions of hundredths 
»to iixty-fonrthi of an inch is given in chart 51, page 115. 

**0n actual testa it has been found that by adjusting the air gap properly almost double eom- 
l^'^ssion and more than double po'tver has been secured. 

tVv«f It \ifl^«'^*^ltAet ^*^ , Ae86e»^ afl to ^ action. -,« 




Remarks on Exhaust Valve Opening and Closing. 

Exhaust valve opening: when we come to the opening of the exhaust 
valve, there are no two opinions about it. 

The valve must open considerably before the piston reaches the end of 
the explosion stroke, and if this wastes some of the force of the explosion, it 
is amply compensated for by the freedom afforded the piston in commencing 
the exhaust stroke. 

It would obviously be wrong to keep the exhaust valve closed up to the 
very moment before the piston is about to move upward, because on com- 
mencing the exhaust stroke it would find itself confronted for an instant with 
the force which had just driven it down, and until the valve was wide open, 
it would be considerably impeded on its journey. 

So the exhaust valve is usually opened as soon as the piston has moved 
through about seven-eighths of the power stroke; that is, before bottom dead 

Exhaust valves opening too early causes a waste of power. Sta- 
tionary gasoline engines, which run at much lower speeds than automobile 
engines, do not hold their valves open so long, the chief difference being in 
the times of exhaust opening and inlet closing. 

Other effects of valve timing are dependent upon the short or long stroke, the side 
valve, as in the "L" head, the opposite valves as in <<T" head, and the overhead valves, 
Ugh and low compression. All this must be considered in valve timing. 

The tenn "valve timing" refers solely to the points at which the valves open and 
close and does not in the present section include the height to which they lift, (see 
page 95.) 

The most sensitive point in the cycle of a four cycle engine is the top center poai- 
tUttkt between the exhaust and induction strokes, for the reason this is the critical scav- 
enging point. 

At a certain point before the bottom of the firing stroke, the ezhanst valve la opened, 
and kept open during the succeeding exhaust stroke, to enable the ascending piston to 
expel as much of the exhaust gas as is within its sphere of action, but, having come to 
rest at the top of its stroke, there is still the contents of the combustion head yet to be 

Exhaust Valve Closing. 

As to when the exhaust valve should close, there is but little to be said 
about it. Suffice it to say that it may not close before the end of the stroke. 

As a rule on account of what we have explained about the gas which 
remains in the head of the cylinder being slightly under pressure at the end 
of the stroke, the valve is quite often allowed to remain open until the piston 
has moved slightly down on the induction stroke, so as to give full opportun- 
ity for as much exhaust gas to escape as possible. 

In order to understand just how important it really is to expel all of 
the bnmed or exhaust gas, it must be explained that one of its chief consti- 
tuents is carbon dioxide — which is the most powerf'il anti-combustion agent 
known to science. Its presence, therefore, even in bmall quantities, retards 
considerably the speed of the explosion development. 

The piston now having come to rest at the top, we are still faced with 
the problem of dealing with the volume of burned gas which remains, and for 
the expulsion of this we must take advantage of exhaust momentum. 

The manner in which this principle operates will be apparent if the con- 
tents of the exhaust pipe is pictured as a mass of gas moving outwards with 
explosive velocity. When the influences which started this movement have 
eeased — ^namely, at top centre — the gaseous mass will function almost like 


iton of an extrmetor pam|i. and if tkc TiiTe timingr permits of it will 
> withdraw a larg«? proporoon of tiie residual gases from the cylinder 

will now b*r obT:o:Ls fro3i xk^ foregoing that, if the extractor action of 
aaust gas^ U :o b-* taken a*^vantage of- the vahre must be made to doit 
» later than "top center/* or — as it is technically described — ^must have 
iin degree of •'lag:" for it is evident that if we close it at the ezaet 
the stroke the contents of the combustion head (which we wish to get 
^ will be imprisoned and will contaminate the 'incoming chargo. 

tie amount of this '^hig" win depend on seraral things— the shape of the 
5tion head, the weight o: the valve, the strength of the springs, and de- 

f the exbaust svstem 

Valre Effect of **Lag*' or Bonnco. 

. regmrds v^ve spring, strecgth mad weight, this has to be reckoned with on ae- 
Df lU influence on tnartia Ug u distinct from that which is Intentional, for it it 
nown that as the speed of the engine increases the valve tends to «'jmnp" the 
-^ *** ^*°^ *^^ closes later and later as the speed increases. Thia is what 
jcnbe as •inertia lag." There is a point however, past top center that the ex- 
extraction lasts, and pen.iing this extracting effect the valve should remain open, 
earned beyond this point, a reverse of the exhaost gases may occur, for it miwl 
rorgotten that the piston has now started down on iU suction stroke. It become! 
Uon therefore, of closing the valve when the scavenging is as complete as possible. 

rhe best design of cylinder head for an ''overlap" is the round or *«I" head with 
T\. Tv ^' ^* ordinary "L'* head is not so good, and in certain kinds of heads 
ieh the inlet and exhaust valves are smaU and close together in a 'smaU poeket 
»rlap is quite useless. 

n the other hand, it has been found in racing practice, where the exhaust pipe if 
long, straight and open, and the combustion head suitable for scavenging, that a 
considerable overlap can be aUowed with advantage. 

11 some instances however, the exhaust valve is made to close on top, for instanse, 
ocomoMle engine which is a "T" head type (see page 108). 

What Governs the Valve Timing. 

The different size of cylinder, especially in the stroke and in the type of 
ion, shape of manifold and the speed of engine, govern the valve tinung. 

Early setting of valves on an engine will cause irregular running at 
r speeds, unless a very heavy fly wheel is used. It will also increase the 
line consumption in short stroke engines. 

For high speed work, the inlet may be opened and closed late. For ilow 
d work, closing the exhaust and inlet on center, gives the best control 
no blowing back. 

The time of opening and closing of valves with reference to the engine 
d, of course has an important bearing on its performance. If the valTif 
I too early it will cause back-firing, while if they open too late a sluggish 

ne and overheating will result. 

Bigh speed (short stroko) engines, have a longer time of valve opening than rnsdima 
ow speed engines. The slower speed engines have the exhaust opening and the Inlet 
ag, nearer to bottom center, while some high speed engines open the exhaust 65* befoia 
)m center and close the intake 70* after bottom center. 

Valve timing of different engines will vary according to its intended average gpeed and 
ength of stroke. Long strokes are for slower speed engines than short strokes. Ob- 
ily high-speed engines are not efficient at slow speeds, because the inlet eloses too 
and the exhaust opens too soon, thus losing part of the charge and part of the power 
ce. And slow speed timing on a high speed engine does not permit of receiving a foU 
ge nor of getting rid of the back pressure during the exhaust stroke. 

The value of the design of the cam, can and nearly always is, lost through improper 
e clearance or air gap adjustment (see pages 95-107). 

»Sfe indei for "Oomprtuion" — for rtUtion of comprei»lon to cylinder head. 


Many people who think, because an engine is new or has just been overhauled the 
tiniiig must be right,^— will have a sad awakening if they will only spend a few minutes 
in Terifying the timing. 

Moat cam shaft gears or fly wheels are marked to insure proper meshing of gears or 
•hseking on fly wheel and proper location of the cams. Some times carelessness at the 
fMtory in marking this gear may mean that after the first removal of the gear, it will be 
replaced wrong, because the marking is wrong (see pages 102, 112, 113). 

Periods of Time Valves are Usually Open. 

Before taking up &iis subject in detail we shall again review the relation 
of the speed of crank shaft to cam shaft and get the name of the parts clearly 
in mind. 

A stroke, is the movement of the piston from the top to the bottom, or 
from the bottom to the top. This motion is called reciprocating motion of 
pisten. When the piston goes from either top to bottom or bottom to top, 
the crank shaft turns one-half of a revolution. 

Therefore, four strokes of the piston would represent two revolutions of 
the crank shaft. 

The cam shaft turns one-half as fast as the crank shaft, because the cam 
fear is twice the size of the crank shaft gear which drives it. 

*The nose of the inlet cam is usually shorter on its length of face than the 
•zhanst cam. Because the exhaust cam holds the valve open much longer 
period of time than the inlet cam holds the inlet valve open. 

The cams which operate the valves are steel forgings,. turned and ground 
to correct shape. They are then case-hardened to decrease wear, and are 
nsaally an Integra" part of the cam shaft. 

The shape of the cam determines the actual lift of the valve and the 
time during which it shall stay open. Chart 44, page 94, shows how cam 
eoi:<tour8 are plotted and several generally used shapes. 

Cams which are pointed give a slow opening and slow closing, the great- 
est opening being at the middle of the valve lift period. 

Cams which are more nearly square, open the valve rapidly, keep it 
nearly wide open until ready to close and then allow it to close quickly. 

It is usual to so design the positioning of the cam shaft and valve tappets 
that the tappets are not directly over the center of the shaft, but are o£bet 
dightly on the lift side. This gives a more direct lift instead of a side thrust 
as would be the case if they were centered. 

In actual practice, the inlet valve seldom opens on top, as shown in 
chart 26 (page 54) but usually after the top of stroke, varying from 5 to 15 
degrees as explained in fig. 1, chart 46. 

The inlet seldom closes when piston reaches bottom, but from 5 to 88 
degrees after the bottom. (See fig. 2, chart 46.) 

The uhaust valve seldom opens on bottom, but usually 40 to 50 degreees 
More bottom (fig. 3). 

The exhaust valve seldom closes on top of stroke, but usually 5 to 10 
degrees after top. (In fig. 4, chart 46, illustration shows exhaust valve clos- 
ing on top, in order that reader will more clearly understand the illustration.) 

The cam turns the same speed as the cam shaft. The nose on the cam 
nites the valve. Therefore the inlet valve will be raised once during the 
four strokes, and the exhaust valve will be raised once during the four strokes. 

*ai •■• fir 

*▲ point which toffresU iUelf on the timing of the inlet opening, and which aUo holds true for 
mitions on the timing circle, it in the tecuring of a quiet cam. Quietness in the cams ii 
■eeored at the tacriflce of power. A steep cam is as a rule more noisy and more powerful 
firing a slower opening. 

To loenre the full opening of the inlet valve at a point which will not he too late to permit a full 
■i to bo tokon into the cylinder, and yet at the same time to have a cam which will not be Boic7« 
that the inlet qpening will have to be started fairly early. This is one of the points which often 
a maker to sacrifice the vacuum to some extent for the sake of quietness. 


I S 

I I -I 

■■ 'x'*' 

4 ' 


. ■' ."".'• 



— • — ■«.'-• J 

KimiiiilA: liii«l ojM'iis 8" after top. closes ."^^ after bottom. Exhaust ope^^- 
4«i* ln»foii» iMitt.niii mikI (:Ios«'H on top. 

r«t I iiiliit. Valvij Startlnflf to Open H' after top center ("TC") (viewing engii^^ 
fiofn ri.'uf . iiiih' tlii> iiiK't will rnnain open during suction period until crairT 
i-i v^ \\\\v\ Imkioiii iinhr Ciur'). The period of travel of the crank during sis:^^— 
tt»»:i piMlod Is ■.'Ml Tho inh't valve Is open during this period. 

r»i; 'J Intct Viilvo ha.s Closed arul piston will now travel up on compression '^'^ 
tvj' .i'Mti'i » IT 'I'ho poriiul of travel of crank during compression period is 14S^ 

ri|B .! Th<» Spark Occurs at Top liii aclual practice, just before the top^ 

\\\s . io .' t!'..' .^rxt stvokc duuii will l»c power stroke. 

N.'t. ',!;.• ;-...xsl v»: t:;»\tl of crank pin during: power stroke 

■ '• "^ '-1 :»- r-.v- c\!i:njsi \:il\f st;nt> \o open at is'.*' 

>, »• .■ :.•;..* \.«'r i\:::»;:>t i;un MX slaitil'.fT to Oj on 


Vc'.«^;v r^stiMi ro.ichos bottom. 

F:^ $. *.::*j»trate« all tb« 
«>."(# := o=f illustration. 

.--v-^^^^'x"?- Ss^^Msca. Pow«r and 


By referring to fig. 5^ chart 29 (page 58), note inlet cam on first stroke 
will be in position of (1), and wil! turn from 1 to 2, or 90 degrees daring the 
first stroke. 

Exhaust cam will be in position (2) and will turn from 2* to 3, or 90 
degrees during the first strobe. 

During each stroke the cam moves 90 degrees, whereas the crank moves 
180 degrees. 

Inasmuch as a stroke of the piston is from top to bottom, or 180 degrees 
travel of crank, it will then be necessary to distinguish the difference between 
the time of opening and closing of valves and the period of travel of the crank 

shaft during the four, actions of suction, compression, explosion and exhaust 

periods. (See chart 46). 

Meaning of Valve Lap. 

The word **lap'' is used often in connection with valve timing, also 
firing order of cylinders. 

In speaking of firing order of cylinders we speak of one cylinder ''lap- 
ping'* another, for instance, on a certain eight cylinder engine there are eight 
periods of 44 degrees travel of crank when two cylinders are on power, or 
** lapping" at the same time. 

In using the word "lap" in connection with valve timing, it means the 
Pei'iod of time that both valves are open at the same time, or -|- (plus lap). 

We will divide the laps into "zero lap," — (minus) lap, and -|- (plus) lap. 

Zero lap: If the exhaust valve closed just as the inlet valve started to open, we will 
^^*'«i this, "zero lap" (no lap at all). 

The ''zero lap" means exhaust closes at the same time the inlet valve opens. With 
^^^o lap there is no vacuum in the cylinder at time of inlet valve opening. 

ICinas lap: If the exhaust valve closed before the inlet valve opens; this we wiU 
^^ll ''minus lap," designated with a ( — ) mark. 

The " — minus lap," which is the general condition used on most engines, the ex- 
^^ust closes an appreciable period before the inlet opens. This permits the piston to 
^e«cend slightly on the suction stcoke before the inlet valve opens, thus creating a 
^&€uum in the combustion space. Therefore, the rush of gases into e7linder is greater, 
^tie to this partial vacuum. 

By referring to fig. 1, chart 29, note exhaust valve closed 1>efore the inlet starts to 
^p€n; this would be termed ** — minus lap." 

Pins lap: If the inlet valve opened before the exhaust valve closed; this we wiU 
e«ll <<plus lap," designated with a -|- mark. 

The ' ' -|- lap, ' ' means that both exhaust and inlet valve are open together for a period 
^t the lap. In other words the inlet 6pens before the exhaust closes. The theorj is 
^^t the inertia 6t rush of exhaust gases passing out the exhaust port is sufficiently 
Srest to create a partial vacuum, and causes a stronger in-rush of fresh gas. 

Owing to the fact that the exhaust and inlet gases should not conflict in their 
Erection, the -|- plus lap is generally used on *<T" head engines. 

See paf^e 114 Bud note the average valve timing of varioas engines. Oompare the inlet valve open- 
^^C and exhaust closing. 

Valve ''Lag'' and Valve ''Lead." 
If a valve opens late or remains open after it is supposed to close, it is 
*W to "lag." For instance, the exhaust valve is usually allowed to **lag" 
About 10 degrees after leaving top of its exhaust stroke before it closes. 

Valve **lead" usually applies to the valve opening before piston reaches 
top or bottom center, this distance is called **lead;" if it closes after center, 
this distance is termed "lag." 

For instance, the setting of spark is sometimes given a "lead" or the 
exhaust valve is usually given a lead of 46 degreep, meaning opening before 



Piston to 
Bw on on 
apteh top 







//VlfT , 
C4Af ^ 

EX. CAM ■ 


it > 




^•=*_'^ CRAfiM jUA^r . 

View from froDi of englntv B^li>w th« view- iq firoin tbe rear. 

fiff. 1. — To aet t&« cun for valTe opening on 
jm "L" boftd ejlludor It 1* otdf nacaiairy to 
*tt tb* OHO cun, vbieh ifi the oMh^ust catn^^jil 
th* doviiif point. If eugloe baa k mttUlpIe of 
e^llDdert all other cmmi ' will then operAt» mm 
Ihey fboold; at *I] exhaaiC aod All Inlet cami 
■r» OB tba OQe «im ihmft and are let per- 
mftB^Ely wheo cam shaft ii made. 

ri£. 2. — WSiOD setting Talres on % '*T*' 
he«d cTllndftT esfflne, tltefo are two cuui to p«t; 
the iolirt and tha ^xhaujB.t. If cjlipder U a fotir 
or »|2, or asy maltiple of cylisders: by tettinc 
the earn oa the flrBl. or laj. No. 1 cylioider — 
ii all tbat ia neceuarj. 

Tbe tisti«l plftn li to set tb« txhMiat as It U 
J^it claslng, and the inlet as ll Is Just opening. 

On a "T" bQa4 all exhaust csmi are on the 
exbsctat earn shaft and atl Inlei eama are on 
the Inlet esm shaft. 

Example of Ysl¥e Timing. 

iplepi iet vaWei as follows; exhaust 
ctoaes t^* after top, inlet op«ns 10* 
after top- 

There ore qsqsUj msrks on Uis fac« 
of £1; wheslp wbiob indkate the position 
far placing the crank ihsft when setting 
I lie i'am«^ 

For Instsucs: when pin ton of No. 1 and 
No. 4 or 1 a&d €, cyli&dera are on top of 
stroke, a tine trill often be made on fiy 
wheel which la auppoaed to line np with 
s tn^rlc on the eylinder, or with *' Indi- 
cator' * placed DO lower part of rear cyl- 

Tbts Uno wUl read **Jlti 1-4 UP" (If I 

cylinder engine)', meaning *'l snd I are 
oa d^sd center-up" (or *'D0 16 UP," 
if a six cyZiudtfr). 

If toOiaust dosed £Vi* after opp«r 
dead centetr, then a marl would appear 
on fif wheel 3%* further away ft^m. 
the center mark {standing in rear of fl>' 

If liklet opened 10° alter upper daad 
cental, then another mark would appear 
a I shown. 

'L*' bead oagine. first place No. 1 platen on doad center (BO), then 
"ZC*' {exhaust cloiiag), and let r^chsuit cam at the cloiing point. 

To s«t **T*' liaad, firit place Ko. 1 platon on dead center with "DC" line. In line with *'indl- 
'^atorp" then more fly wheel to left to '"EC" — -set ejihnutt vulve closing, Hext, move fly wheel still 
furtb«t to "10" <]Qlet opeuiuff)* and set inlet cam at opeuing point. Mesh the gears and ralTea 
ar* bifflfed. 

Tlalnf TilTts on a round or **I*' bead cylinder with vaKoi overhead, the procedure is the 
St ict ^^e "L" urilr^R vmlvL-ji arc oii oiiposite aide^ hk on a *'*r'« bead. 

To then set ths valvo on 
■«T« fly wli«^t to \*^h ^Vt^ to 

CHART NO. 47— Timing Valves on a **T & L" Head OyUnder Engine. Example 9f Fly Wheel 

Wott: At. r ; '*»or i^ alto t»Tm»d a "trammel " 


bottom. The faster eugines are designed to run, the greater the amount of 
'4ead" or "advance" given the opening of the exhaust, also the spark when 

Valve Timing Position. 
The position of the crank shaft determines the position of the piston. 

The position of the piston determines the point where valve is set to 
open or close. 

Therefore the cam shaft must be so placed, that the cam will raise the 
valve when piston is at a certain position. 

*This is accomplished by meshing the cam gear with crank shaft gear 
when piston is in correct position. 

Marks are usually placed by the manufacturer on the cam gears which 
win indicate just where to mesh gears (see page 106). The fly wheel is sel- 
dom used for timing unless there are no marks on gears or if it is desirable 
to check the valve timing. 

It is also important to secure the proper valve clearance as per pages 
94 and 95, before timing the valve. 

Setting Valves on a Single Cylinder Engine. 
For instance; suppose the valves are to be set on a single cylinder *'T" 
head engine with exhaust to close on dead center, and inlet to open one-eighth 
inch after top on suction stroke. 

Setting exhaust valve: first; place piston (by turning crank shaft) on 
dead center, then mesh exhaust cam gear with crank shaft gear, so that ex- 
haust valve is just seating. (See fig. 1, chart 46.) Sett^ inlet valve: 
move piston down one-eighth of an inch from top, mesh inlet cam gear with 
crank shaft gear. 

It will be noted that the inlet opens and suction stroke begins right 
after exhaust closes. Therefore the closing of the exhaust and opening of 
the intake is the point to Work from. 

A matter of importance to remember, is the spark. When setting valves, 
be sure the contact on timer or magneto is set to occur when piston is on top 
of compression stroke, a full revolution from where inlet valve starts to open. 
(This will be treated under ignition timing.) 

Also remember to first get the ** valve clearance'* or **air gap" correct 
as per pages 94 and 95. 

Setting the Valves on a Multiple Cylinder Engine. 
Setting the valves on a multiple cylinder engine is identically the same 
operation as timing a single cylinder engine 

tif there are a multiple of cylinders, say four, then there must be at 
least one inlet and one exhaust valve for each cylinder. Therefore, there 
must be four cams for the four inlet valves and four cams for the four ex- 
haust valves. 

If engine cylinders are "T" head, then there are two cam shafts; one 

for the inlet valves and one for the exhaust valves, placed on opposite sides 
of the cylinders. 

If cylinders are ^'L" or **round" head with valves in the head, then 
there is but one cam shaft. (See chart 40, page 86). (On some 8 and twin 
six engines however, there are two cam shafts.) 

tin tome of the late makes, each cylinder has two inlet and two exhaust valves, called "dual valvet.** 

8e« pages 109. 927. 
^Sometimes rererting the crank shaft gear will give better results, due to key-way being slightly offset. 


It is well to note that even though there are four cylinders, six, eight 
or twelve cylinders, each of the pistons must pass through the four strokes 
during two revolutions of the crank shaft, even though two of the cylinders 
are firing at once during part of the time (which they are in a six, eight and 
twelve cylinder engine). 

Just how these four strokes are made by each piston during two revolu- 
tions of the crank, is explained under ''firing order/' instruction- No. 10. 

We will next take up the method of setting the cams, so they will open 
and close the valves at the correct time. 

If a four cylinder engine, remember that owing to the shape of crank 
shaft, pistons 1 and 4 are always up or in line, when 2 and 3 are down, or 
vice-versa (see page 116). If a six cylinder engine, pistons, 1 and 6 are in 
line, 3 and 4, and 2 and 5 (see chart 55). 

If cylinders are "L" type or "round" type, with all valves on one side, 
then it is only necessary to set the one cam shaft, and do the timing from one 
cylinder, usually the front one, see fig. 1, chart 47, page 102. 

If cylinders are "T" type, then it will be necessary to set the inlet cam 
shaft and the exhaust cam shaft separately, but it is necessary only to set 
valves in one cylinder, as the other cams are fastened permanently on the cam 
shaft, and must open and close all other valves at the correct time. See fig. 
2, chart 47. 

Therefore the cams do not need to be set on the shaft, but by meshing the 
cam gear in fisont of Hlq engine with the drive gear, the position of the nose 
of the cams can be adjusted. The usual plan is to place piston of No. 1 
cylinder at the top of its stroke, and work from that point. 

An eight cylinder engine, usually employs one cam shaft with 8 or 16 
cams. The Cole has 16 cams, one for each valve whereas the Cadillac has 
eight cams. 

To set the valves of the Cole engine, place piston of No. 1 cylinder on 
top dead center, then turn fly wheel in direction of rotation say 10°, to 
where the exhaust is supposed to close, at this point mesh the exhaust cam 
gear so exhaust valve is just closing, or cam is just. leaving the end of valve. 
Either side can be timed, which will suffice for both sides or sets of cylin- 
ders. Usually the right side is timed. 

f Timing Marks on Fly Wheel. 

The usual plan to time valves or set in correct 
time with cam shaft, is to mesh the cam gears with 
point marked thereon to correspond with the 
mark on crank shaft gear at the time No. 1 cylin- 
der is on top of its stroke. 

Usually marks also appear on the circumference 
surface of the fly wheel, which indicate position 
crank shaft is to be placed for correct setting of 

The mark on fly wheel is placed in line with a 
center mark on cylinder or elsewhere. 

If there are no marks on gears or fly wheel, 
then it will be necessary to first determine where 
you wish to set the valves. 

*Noie — Alw^jn adjust Talre clearance before proceeding to aet valve, see chart 44. 

Sea Dyke's 4 and 6 cylinder enfine models. 

tBy referring to inserts and page 120 an "inspection hole'* will be noticed in hovalng over fty 
wheel for observinf marks on fly wheel. 


Timing "T'' Head Cylinder Engine Valves. 

Although fly wheels and cam gears are usually marked and the setting 
done with gears, the explanation will show how to check the valve timing 
and mark fly wheel if necessary. 

For instance, suppose engine was a ''T" head four cylinder type of en- 
gine, and you wished to time the valves as follows: Exhaust to close 15^ 
past Upper dead center. Inlet to open 8° past upper dead center. (This is 
an unusual timing.) 

In actual timing this is really all that is necessary to know, as the 
other points of closing and opening will be takeji^ care of by the other 
cams on cam shaft. 

♦Procedure of marking fly wheel: (Refer to illustration.) Place No. 
1 piston on top or upper dead center. Mark a center mark on cylinder, 
(usually on incQcator or what is called a ''trammer' is placed at this point, 
see fig. 3, page 102). Now mark a line on face of fly wheel and mark on this 
line "1-4 UP," meaning pistons 1 and 4 are on upper (or top) dead center. 

fNow measure 8 degrees from this line to the right and make another 
mark on fly wheel — mark it "10." meaning inlet opens. 

Now mark another line 15 degrees from the DC line, to the right on fly 
wheel — ^mark this "EC," meaning exhaust closes. 

Next, turn fly wheel slightly until line marked "EO" is in line with 
indicator or punch mark on cylinder. At this point piston is 15° down 
(measured on fly wheel) in direction of rotation from top. Note that yon 
are supposed to be in rear of fly wheel. 

Setting exhaust cam; take exhaust cam gear out of mesh with crank 
shaft gear (if a gear, or if a chain loosen chain) ; turn exhaust cam in direc- 
tion of rotation (note direction it turns, fig. 2, page 102, opposite that of 
crank shaft) ; place exhaust cam at closing point (see chart 47, fig. 2). Now 
mesh exhaust cam gear and exhaust valves are timed. 

Setting inlet cam, next, turn fly wheel to left until line "10" is in line 
with center mark or indicator on cylinder ;at this point piston is 8° down 
(measured on fly wheel in direction of rotation from top). Take inlet cam 
gear out of mesh and turn inlet cam in direction of rotation until it is just 
at the point of opening (see fig 2, page 102). Mesh gears and inlet valves are 

Next adjust the "air gap" or "valve clearance" as per pages 94 and 95. 

Timing the Valves on "L" Head Type of Engine. 

Only one cam shaft need be set when all valves are on one side, and all 
cams on one cam shaft, see fig. 1, chart 47. 

The usual plan is to place position of No. 1 piston at point where exhaust 
valve is to be closed, and mesh the exhaust cam shaft gear at this point. 

Timing Valves on an "I" or Round Head Type of Engine. 
The overhead valves are usually operated by push rods. All from one 
side of engine and from one cam shaft, therefore the timing would be the 
same as an '*L" head. 

If overhead cam shaft; the valves are usually operated by one cam shaft, 
therefore the principle is the same, see chart 66, page 137. 

It is important to adjust the "air gap" or 'S'alve clearance.'' 

*A Btudy of flf. 3, page 102, of the six cylinder timing will assist you in understand n:; thit. 
tSee page 116, how to convert degrees into inclies or fraction therrof. or just how far in inche* 
*o make the mark on different diameter fly wheels. 

tTo find 'position of piston, see index "finding position of the piston." 



'Mtimam Dnvr Cni 

Cnai Hull Caf 

This Particular type is a T' Head Cyl- 
inder type of feSngine. By observing the 
illustration the reader will note the 
principle of valve timing on a *'six" 
differs but little from the "four." 

A Study of Six Cylinder Crank Shafts 
in Chart 55 will explain the meaning of 
the 120* marks. 

When the long mark 1-6 is in line with 
line on Crank Case, pi3ton8 number one 
and six are at their highest points or 
upper dead center. 

When mark 2-5 is in line, pistons number two and five are on upper dead cen- 

When mark 34 is in line, pistons three and four are on upper dead center. 

From Upper Dead Center, pistons are ready to start downward on their intake 
or power stroke as the case may be. 

If the Piston of any Particular Cylinder is Ready to Start on its intake stroke, 
then when the first punch mark from center mark, or lO* of the complete circle 
is in line with mark on crank case, the exhaust valve of this particular cylinder 
has Just closed. 

When the Second Punch mark or 15* is in line, intake valve of this particular 
cylinder begins to open. 

No Reference is made here as to closing of Intake and opening' of Bzhaaii, be- 
cause it is of no particular advantage when timing valves, as the opening of inlet and 
closing of exhaust is all that is necessary to know. 

The only Points to Determine is when the inlet opens and exhaust closes and 
set as shown above. 

To Remove Timing Gears on the Mitchell. Note there are tw« cam shafts ('*r 
head cylinders.) To remove idler gear screw out hexagon headed bolt "D,** which 
has a left-hand thread, from idler gear shaft. 

To remove Cam Shaft Gears. Remove hexagon bolts "A" and hexagon nuts 
"B." The gear now comes off its hub. 

To Adjust Mesh of Timing Gears. Through holes "C of cam shaft gears loosen 
the bolts that hold bearings to crank case. Bearings being eccentric they can be 
turned until desired mesh of gears is obtained. No further adjustments of the other 
cam shaft bearings are necessary to make this adjustment. Be sure bojts are again 
drawn up tight after adjustments are made. 

To Adjust Mesh of Magneto Shaft Gear. Loosen the three bolts tnat hold bear- 
ing to crank case: bearing being an eccentric can be turned until the desired mesh 
is obtained. 

To Adjust Generator Drive Shaft Gear. Loosen the three bolts that hold bear- 
ing to crank ease and proceed same as to adjust magneto drive shaft gear. 

HOW TO MESH TIMING GEARS; by removing forward end of crank case cover, 
gears can be insppcted. The gears should be so set that the figure 1 stamped on 
crank shaft gear should match with figure 1 stamped on idler gear; mark 2 on 
idler should matcli with mark 2 on cam shaft gear and mark 3 on idler gear should 
match with mark 3 on other cam shaft gear. 

This Piinciple of removing and Tiieshing j^ears is common practice 

OHABT NO. 47A— Valve Timing Marks of a Six Cylinder Engine, 
a ''T" head Engine (Mitchell early model 6-16). 

^^^■ii4«g of Xlmlng fliMHi 4 


-The later Mitchell timing is given in 
type engine. 

'Standard Adjustments of Leading Oart" and la an "L" 



Method of Marking a Fly Wheel in Degrees. 

Although a scale is worked out on page 115 to find in inches or a frac- 
tion thereof just where to mark fly wheel in degrees, another method is given 
below. Suppose there are no timing marks on fly wheel and you desire to 
mark same. 

Set the engine so that the piston in No. 1 cyUnder, namely 
the cyUnder nearest the radiator, is at the top of its stroke. 
With the use ef the protractor or with a square, make a mark 
at A on the rim of the flywheel, on the inner edge, which mark 
wiU be directly above the center of the crank shaft or piston 
is at top of its stroke. 

Then, with the protractor placed against the fly wheel so 
that the 90 degrees mark points directly toward mark A, go 
10 degrees to the right on the protractor (standing in rear 
of engine), then make a mark at B on the fly wheel. TUs 
mark wiU be 10 degrees to the right of mark A. Now torn 
the fly wheel until mark B is at top center. 

With the engine in this position mesh the timing gears so 
that the exhaust valve of No. 1 cylinder is just dosing. 

It is understood that when standing behiad fly wheel it 
would turn to the left or as per arrow point. Therefore, 
piston must first reach top center (A) with exhaust valve 
stiU open, and travel 10 degrees further to (B) before it 

Variation of Valve Timing Marks — on fly wheel. 
Sometimes the marks may vary, for instance, instead of ''1-4 UP*' or 
"14 DC,*' it may appear as, **T C 1-4" (top center 1-4) ^r ''U C 1-4" (mean- 
ing npper dead center), or some similar mark meaning the same thing. 

Some manufacturers vary their marking on the rim of the fly wheel as 

_ ^„ 

Exhaust closes *'EXC" 

foDows: Inlet opens ''IN-O" or ''I. 0." Inlet closes ''IN-C" or ''I 

Exhaust opens '^EX-0" or '*E. 0." or **X. 0. 
or*'B. C."or*'X. C." 

If the figures 1-4 or 2-3 appear after or befqre the above marks, as **l-4- 
10.," this means the number of the cylinders, as **1 and 4, inlet opens-." 

For an example of valve timing 
marks on a four cylinder engine 
fly wheel, see fig. 1— the engine 
fly wheel has upon its face, the 
following marks : 

I. O., meaning, inlet valve openi. 

I. 0., meaning, inlet valve eloiei. 

E. O.. meaning, exhauet valve openi. 

E. C, meaning exhauat valve cloiea. 

U.D.O.. 1 and 4, upper dead center; eyl 
inder 1 and 4. 









1>t -^ 











U.D.O.. 2 and 
inder 2 and 3. 

3. upper dead center; ej\- 

RtAR OF CNGtNf- PLV V»Wtti.. 

Fig. 1. — Valve timing marks on fly wheel of a Reo 
foor cylinder engine. 

These points, marked upon the 
face of the wheel, show where the 
exhaust and inlet valves of each 
cylinder should open and close. 

Taking as a reference point the small boss marked with a cross upon cylinder 
No. 4, next to dash, this being plainly shown in the illnstration, together 
with the marking on one side of the fly wheel. 

The engine cyliDders are nuuihtrfd 1. 2. 3 and 4. No. 1 bfin? next to railiator. and No. 4 next 
It dash. By referring to pages 76 and 78 of crank shafts, previously given, it will be seen that cranks 3 
■Bd f, and 1 and 4 are exactly 180 degrees apart. Therefore, the same marking on the fly wheel 
tiat •ervea for No. 2. alio aervei for No. 3. and the marking for No. 1 serves for No. 4. these points 
Mag exaetly one-half reTOlution. or 180 degrees apart, as before mentioned. 



Fig. 4. Inlet Cloias. 
%** Past Bottom OcDti r 
%, " Past Bottom Centfr 
aad <«48" ilz cylinda 

1. Inlet Opens. 2. Exhaust Oloses. Fig. 3. Exhaust Opens. 

Top Center Vfc " Past Top Center "38" % " Before'Bottom Center 

Top Center H " Past Top Center "48' * 1" Before Bottom Center 

Figures 1, 2» 3 and 4 Illustrate the Ytlf timing of the Locomobile *'38" 
engine. The timing being given in inches. The top line is the timing of the model "38" and th« 
lower line "48." First, adjust the valve clearance by adjusting check nut on valve lifter or plunder 
until it just touches the bottom of the valve stem. The cam is then ott the bottom of the plunger &x)d 
piston No. 1 is on the top of stroke. This will give about .005 of an inch clearance. Next; the intake 
valve is set to open at the top of the stroke, therefore set the inlet cam just starting to open the inlet 
valve at this point. Next; set the exhaust valve at point just closing, when piston is down H of ai» 
inch from top. 

Oadlllac valve timingw Open cylinder relief cocks, turn engine until valve you are timing (hdv 
exhaust of No. 1 right) has just seated. Turn still farther, until line marked '*Ex. i 8." on fly 
wheel, is under trammel on crank case, ^he cam is then in correct position for that valve. 

To check inlet valve — the same proc^^dure. but mark on fly wheel is "In | S." (inlet seated.) 

Fig. 3. — The timing of the Hudson Super Six measured 
according to piston travel: Intake opens V64 after top dead 
center; closes i'^^ after bottom dead center; exhaust opens 
5'(;4 before bottom dead center; closes V&2 after top dead 

These measurements are best for timing, but for compari- 
fon with other engines it is better to state the valve move- 
ment in degrees: Intake opens 7 deg. after top dead center; 
closes approximately 42 deg. after lower dead center; exhaust 
opens abont 55 deg. before dead center; closes 8 deg. after 
top dead center. 

Fig. 6. — Valve timing diagram of 
the Stuts racing engine explained on 
page 109. 

The Stuts (see diagram above) th4> 
exhaust opens 55** before bottom and 
closes 10** after top. Inlet opens 10" 
after top, doses 55* after bottom. 

Dusenberg racer engine: Ex. opens, 
46® before bottom, closes 8* after toi^. 
Inlet opens 4** after top. closes 42* 
after bottom. 

The MaxweQ racer engine: Ex. 
opens 69 <* before bottom, closes 19* 
45' after top. Inlet opens top of dead 
center, closes 32 <* after bottom. 

A prominent French racing engln« 
uses a valve timing of — Inlet opeas 
1012* after top. closes 45* after bot- 
tom. Exhaust opens 45* and cUrttt 
18* after top. 

CHABT NO. 48 — Example of Valve Timing in Inches. Valve Timing of Bacing Engines. 

See page 500 for Locomobile gear shift and page 362 for electric system. The 19S0 Series Five LocoB4 
!.•:!«►? r.r*.r« t^" past top; exhaust closes top center; exhaust opens %" before bottom; inlet closes %" 




The Bnick six valves, both inlet and ex- 
kenct are placed in-the-head of cylinder. The 
Talres are in cages and can be ground by 
compressing valve spring and lifting push- 
rod oat or socket. Loosen valve cage nuts 
sad anscrew valve cage. Remove valve 
spring and after cleaning with gasoline or 
kvoeene. smear the valve and its seat 
with fine emery flour and grind by turning 
back and forth on its seafr until both valve 
sad seat show a bright ring ^9" wide all 
the way round. After grinding clean 
tkonmghlj and adji^st push-rods for clear- 

The Ststi radnc •nglne with two inlet 
and two exhaust valves td each cylinder (4 
cylinders). Valves are in-tlie-heaa of ^lln- 
din and operated bv an overhead cam-shaft. 
Bee page 108 for valve timing. , 







Timing Buick Six, Valves-ln-the-liead, Operated by 
Pu8h-Bods on the Side. 

The valve-in-the-head can be timed in Just the same 
manner as timing the valves when placed on the side 
as described on page 102, but in order to simplify the 
work, quite often, manufacturers mark the timing gears 
as described in the illustration fig. 2. 

Timing the valves: For instance, to time the valves 
of the six cvlinder Buick; the cam shaft gear which is 
marked "O corresponds with the tooth on the crank 
shaft gear as shown in fig. 2. 

Adjusting push-rod clearance: Turn the engine by 
hand (in a clockwise direction, looking at it from in 
front), until the line marked "1 and 6*' on the fly 
wheel comes opposite the line on the rim of the in- 
spection hole. This is the flring position for cylinders 
Nos. 1 and 6, numbering from the radiator back, and 
one or the other of these cylinders will be found to 
have both valves closed, so that both rocker arms will 
have a slight amount of play. The push-rods should 
then be adjusted from the back of the cams and while en- 
gine is warm, so as to have .010 inch clearance between the 
end of the valve stem and the rocker arm. This is approx- 
imately the thickness of a sheet of heavy paper or very 
light card. Push rods for the other cylinders may be ad- 
justed in the same manner. One-half teaspoon full of 
kerosene inserted around valve stem once a week while 
engine is runing will keep valve from sticking in valve 

Setting the ignition on Buick: Turn engine clock- 
wise, as before, until "1 and 6** line on fly wheel 
comes in view; continue turning slowly until line marked 
"7*'* registers with indicator mark (which is approxim- 
ately 1 inch after dead center mark). This is the point 
to set ignition timer. Retard spark. Set breaker cam 
on timer, so lobe of cam is just commencing to sepa- 
rate contact points. Firing order is 1, 4, 2, 6. 8, 5. 
Spark plug gap is adjusted .080" clearance and timer 
contacts points .018''. Timer is Delco closed-circuit type, 
page 377, 378, 388. 

Timing the Stutz Racing Engine, with Valves-ln- 
the-head, Operated by an Overhead Oamahaft. 

An end view is shown. A brief detail of the specifl- 
cations are as follows: 

General: Bore, 8^ inches; stroke, 6^ inches. Four 
cylinders with sixteen valves. 

The maximum power is obtained at a piston speed of 
3250 feet per minute which corresponds to 8000 r. p. m. 
and is about 130 h. p. 

Valves: There are two inlet and two exhaust valves 
for each cylinder, which is termed "dual" valves. The 
valves are operated by an overhead cam-shaft, which is 
operated by a chain of gears from the crank shaft gear. 

Where four valves are used to each cylinder, they are 
known as "dual valves," see page 927. 

The crank-shaft is ball bearing with one inch balls. 
Valve Timing, see fig. 6 page 108. 

QBAST KO. 49. Timing the Valves of an Engine When Placed in the Head of Cylinders; Buick 
ib ud Stnti Badng Engine as Examples. 

Attt 50 oMiited, error in numbering. « 



Oheddng the Valve Timing. 
The purpose of checkiiig the valves is to see if they are opening and 
closing as marked on fly wheel. 

Altiiough it is only necessary to set the exhaust cam so exhaust valve 
will just close, on an ''L'' type of cylinder engine, there are other marks 
which are used for checking the timing. 

As an example a four cylinder en- 
gine is used, with timing scale as 
follows : 

Dead center of cylinder! 1 and 4 are marked 

on fly wheel "1-4." 

Dead center of cylinderg 2 and 8 are marked 

on fly wheel "2-8." 

Inlet valve opens 6* past top center marked •■ 

fly wheel "1-4 IN. O." 

Inlet valve closei 40* past bottom 

marked on fly wheel "1-4 IN. 0.*' 

Exhaust valve opens 40* before bottom eeater 

marked on fly wheel "1-4 EX. O." 

Exhaust valve closes 7* past top center marked 

on fly wheel "1-4 EX. 0.** 

Note — the marking on illustration is merely ft* 

and 7*, the reading at end of arrow lines indi- 

cate the meaning. * 

The same marks appear for cylinders 2 and t. 

The lines on fly wheel indicate the points st 
which the valves open and elos«. 

When fly wheel is turned so that the Uba 
marked "1-4" is up in line with mark •■ 
cylinder — ^No. 1 and 4 pistons are Just at the 
uppermost points of their strokes or at '^wdot 
dead center." When line "2-8" is up in Umm 
with center mark on cylinder the No. 2 and t 
pistons are at upper dead center. 

To determine whether or not the 
valves are properly timed, first open 
the relief cocks on top of the cylin- 
ders, then have some one crank the 
engine over slowly until the line 
marked **l-4*' is opposite the center 
line of the cylinders. At this point 
the exhaust valve in either No. 1 or 
No. 4 cylinder should be just closed. 

If you find that the exhaust valve in No. 4 cylinder is beginning to cloM 
and you wish to check up the valve timing in No. 1 cylinder, turn the fiy 
wheel around to the left (standing in rear of engine), one complete revolu- 
tion, until line **l-4" is again brought opposite the center line of the cylinder; 
then continue slowly turning the fly wheel about three-quarters of an inch 
farther to the left until the line marked **7° EX. C." coincides with the 
center line of the cylinders. This is the point at which the exhaust valve in 
the No. 1 cylinder should just seat itself or close. 

fTo determine whether or not the valve is seated, see if tappet or puah 
rod underneath the valve can be turned with the fingers. If the tjappet 
turns freely, the valve is seated, but if the tappet is hard to turn, that will 
■how that the valve is still being held slightly open. If this is the case, 
loosen the lock nut on the tappet screw, and turn the screw down until the 
valve has the proper clearance, then turn the lock nut down tight against 
the tappet. 

When the valves are closed there should be clearance between the end 
of the valve stems and the tappet screws, of from .003 to .005 of an inch. 
This amount of clearance is necessary to allow the valve to seat tightly 
(see page 95). 

Tig, 2. — ^An example of valve timing marks on the 
fly wheel of a four cylinder engine. See text for 
checking valve timing from these marks. View from 
rear of engine. Note it tnms to the left. 

fThe opening and closing time of a valve 

(Then it makes or leaves contnct — see page 94 


not wluMi the lifter bcpins to rise or comes to 
figs. 2 and 3. 


To check up the tuning of the inlet valve in No. 1 cylinder, turn the 
fly wheel slightly to the right until the line ^'1-4" is in line with the center 
of the cylinders, and then turn the fly wheel about one-half an inch to the 
left, until the line marked **5° IN. 0." coincides with the center line of the 
cylinder. At this point the inlet valve should just begin to open. 

Continue turning the fly wheel half a turn to the left, stopping when the 
line marked "40^ IN. 0," just to the •right of the line *'2-3" comes in line 
with center of the cylinders. At this point the inlet valve should just close. 

To see if the exhaust valve in No. 1 cylinder opens at the proper time, 
revolve the fly wheel still farther to the left, and stop when the line "40^ 
EX. O," which is the first line to the *left of the ^'2-3" center line, comes 
up in Line with center of the cylinders. This is the point where the exhaust 
valve in No. 1 cylinder should just begin to open. The above operation com- 
pletes the checlang of cylinder No. 1. 

^o check the timing of cylinder No. 2, turn the fly wheel until the line 
marked "2-3" is in line with the center line of the cylinders. If the exhaust 
nJve in the No. 2 cylinder is closed, turn the fly wheel through one com- 
plete revolution, until the line "2-3" is up again; the exhaust valve in No. 
2 blinder should then be just starting to close. Proceed now the same as in 
timing the No. 1 cylinder. The valves in cylinders No. 3 and No. 4 are timed 
in the same manner. 

Qylinders No. 1 and 4 are timed from the center line "1-4"; 5° to left 
Cor inlet opening and 7° for exhaust closing, and cylinders No. 2 and 3 from 
the line "2-3;" 5° to left for inlet opening and 7° for exhaust closing. 

n Is adilnblAv whon ebeddng th« opening and closing points of the vjaves with the mtakM on the 
9f «feMl» to make » note of the vmrlAtlon of each of the valves from the marks in the fly wheel. 

Than, after all the valves have been checked yon can compare the variations for the different 
falv« and in this way detennine whether the variations are due to the large time gear on the and 
tf lia CHB Aait not being properly set with relation to the timing gear on the end oft the crank- 
' '1^ ir to waar in any particular cam or valve tappek A variation, not to exceed one-half of an 
titker way from the lines on the fly wheel, is permissible, and will not make any material 
raaea in the timing of the valves. If the variations exceed this and are uniform for the dUferant 
nlvia the eorreetion should be made by re-setting the cam shaft gear. (See "setting of timing 
" thia page.) 

tha Tatrea ara closed there should be clearance between the end of the valve stems and 
WWl, of from .003 to .005 of an inch. Thia amount of clearance is required to allow 
Me'valTea to seat tightly. (See "valve clearance." pages 94 and 95.) 

The Timing Gears. 

Since the position of the cam shaft is always the same with reference to 
the pistons (because the cam shaft is always in mesh with the crank shaft 
fear), and since the cams are all integral parts of the shaft, the valve timing 
eannot change. If the gears are ever removed, they may be put back in the 
proper position by seeing that the marks on the edges of the teeth **dove- 
tiil" together. 

If the timing of the valves of an engine is not correct, it is then necessary 
to xe-meah or re-set the timing gears. It will be necessary to place piston of 
No. 1 cylinder at top of its stroke. Then remove the gear cover and turn 
cnnk until the **EX. C" (exhaust closing mark of cylinder No. 1) is in line 
with center mark on ^cylinder (in rear). Now remove the cam gear from its 
Aaft and turn cam shaft in its direction of rotation (it is opposite from direc- 
tion of rotation of crank shaft), until the exhaust valve on cylinder No. 1 is 
)st dosingy keep the cam shaft in this position, replace the cam gear (large 
one) on the end of the cam shaft properly with the gear on the 
cnnk shaft. 

tOlL anglnaa Wttta unit power plants the center line instead of bein^ on cylinder, ri sm:il1 hole at 
t*5 ef ^7 vneel case is provided so line and figures on fiy wheel can be seen throufjh hob>. see pa^je 120. 

tTka opaoiniT *&A eloalng time of a valve is not when the lifter begins to rise or comes to rest, 
Wt vhsa it makes or leaves contact — see page 94. 

*1fkaa *'S-S" 1^ wliaal mark is at top this marking would be at the right of 2-3. Below, as 
« iiaev in ilhutratTon, it U to the left. ' 


^c-siHii When the gears are originally in- 
stidled at the factory, there are usually 
marks stamped on the small crank shaft 
gear, for instance, a letter *'0" or ''C,'' 
or figures 1 or 2,and a similar mark is 
stamped between the two teeth of the 
larger cam gear with which it meshes. 
At this point the valves are supposed to 
be correctly timed. 

If you find that the marked teeth do 
^^i^iLT - '"' ^^* come together; do not jump at the 

Fig. 1. — Note meshing of crank ehaft gear mark COUClusion that the fiTCarS are imprOPCr- 
(1) between the two teeth on cam ahaft gear « j. -u ± n j, -^j.!. j.^ t. 

mark (1). This is the Overland model 86. ly SCt, DUt firSt VCniy the Setting by 

Note the cam shaft turns in opposite direction checking the timing of the ValvCS wlth 
to erank shaft when the crank shaft gear drives i i.u n iT i 

the cam ahaft gear without using an idler gear. marks OH the tty Wheel. 

Bemarks on tlie Relation of Timing Gears to Valve Timing. 
After your engine has been overhauled a few times the cam shaft gear will have 
developed a dozen or more meshing marks; each workman having added a few marks 
that maj or maj not be right and changed a few that were right until finally it is hope- 
less to match any of them. 

This need not seriously inconvenience yon, for if you understand valve timing, you 
ean forget the gear maiks and work Entirely from the fiy wheel marks. 

A "trammel" is a stationary starting point to base all your work from (see fig. 8, 
page 102). The trammel generally is directly over or in front of the fiy wheel, but may 
be located elsewhere if some careless workman has removed your fly wheel and replaced it 
in a different position (flange connection or a new fly wheel with key in wron^ place); 
the trammel should be shifted until it registers properly when the cylinder indicated is 
at top center. 

Check up the top center mark by making sure that the piston in the cylinder in- 
dicated is exactly at top center and that the trammel registers exactly in line. 

Now that you are certain of the trammel, move the fly wheel in the direction it 
should travel ( generally counter clock if fly wheel is between you and the cyinders) until 
the mark I. O. (intake opening) No. 1 and No. 4 registers with the trammel. Leave 
the fly wheel alone now and turn the cam shaft until the nose of the inlet cam on No. 
1 cylinder is down. Adjust the air gap for post card distance Turn the cam shaft in 
the direction of its travel until the air gap is gone and any further movement would 
start to lift the valves. Put on the cam shaft gear, being careful to not move either 
the cam shaft or the crank shaft. Have the gear key in place but don't permanently 
fasten the gear yet. 

Turn the fly wheel in its proper direction and check up the intake closing. If 
both opening and closing of this valve are right, it means that the cam shaft and air 
gap are correct and the gear can be permanently fastened. 

If the valve opens on time but closes at the wrong time it means that both the 
cam shaft and air gap are wrong. If the valve closes too soon the air gap is too large and 
doesn 't hold the valve open long enough. If the valve closes late, the air gap is too small 
and holds the valve open too long. (See page 95.) 

Make a mark with a lead pencil or chalk on the fly wheel, midway between the 
actual closing and the proper closing. Turn the fly wheel to this new mark and ad- 
just the tappet to correspond. The tappet must be just barely in contact with the valve 
stem. The air gap is now O. K., but the cam shaft is still out of time. 

Turn the fly wheel back to the opening mark and remove the gear. Turn the 
earn shaft until the air gap is gone, replace the gear and check up the closing. The 
earn shaft and air gap are now correct and the remaining tappets are adjusted after 
registering each mark with the trammel. Don't use a sheet of paper or post card te 
measure with. Turn the fly wheel and adjust each tappet by the fly wheel marks. 

If the valve opens a certain number of degrees early and closes the same number 
of degrees late, the cam shaft is right but the air gap is wrong. 

If a valve opens a certain number of degrees early and closes the same number of 
(Ifgroei early, the air gap is right but the cam shaft is wrong. 

Make a habit of checking up this air gap at least once a month, especially if you 
hav(« tlbro inserts or any other noise silencers. Use the fly wheel marks. 

After the valves have been ground or new valves put in — check up. . Don't let 
v^wr engine overheat or lose power through the fault of the air gap. 

*Te asstmhie 1<"*<"g gears on the Dodge; turn crankshaft clockwise until top of No. 4 piston is 
w» toy «•! below ton of cylinder, on coinpression stroke. Then rotate cam shaft connter-eloekwiee 
Juftil >flk s Mhauat vaWe is ready to open. Tlio crankshaft and cam shaft gear should then be meehed 
JITlLl Ibe MttfU pSch mark in the latter is between the two on the former. 



Where silent chains and sprockets are used instead of gears — the pro- 
cedure is similar, except the cam shaft revolves in opposite direction. 

The earn shaft, generator and magneto shafts are 
driven from the main shaft by chains at the front 
of the engine. The timing of 
these shafts, or the relation of 
their operation to the crank 
shaft, determines the time of 
opening and closing of the 
valves and the firing of the gas. 

Should the chains be removed 
proceed carefully when reas- 
sembling as follows: 

Turn the crank shaft until the 
mark "1-4 UP" on the fly wheel, 
lines up with the mark on the cross 
member, and with No. 1 cylinder 
ready to Are. 

Turn the cam shaft until mark 1 on the sprocket is opposite mark 1 on the crank 
•haft sprocket. 

Now torn the magneto shaft until the distributor makes contact with No. 1 brush, 
the lower right-hand one. Mark 2 on the magneto sprocket should now be opposite mark 
2 on the cam shaft sprocket. 

tWrap the chain around the sprockets and fasten the master link. The parts should 
BOW operate in their correct relation, (see also page 648.) 

Notes relAtlYC to gears: To reach the gears it is usually necessary to remove radiator, then 
the starting crank stud, then fan, fan pully and gear housing cover. When replacinflr be sure the ' 
gaaket of housing is in good condition. The gears are usually keyed and locked in place by a nut 
on end of shaft. On most gears there are two holes for a "gear« puller'* (see iiidex), whieh is 
used to draw off the gear. Should it be necessary to remove the cam shaft sprocket from the hvb, 
see that it is replaced with the tooth marked "0" directly opposite the keyway. 

Valve Timing of a 6 Cylinder^ Engine. 

The process is identical with that of a 4 cylinder engine. If all valves 
are on one side, it is only necessary to time the exhaust valve closing of 
cylinder No. 1. See page 106 for an example 

The timing of a six cylinder engine in *inches instead of degrees is 
shown below. Also see page 109. 


Fig. 2. — Note on the Overland model 75. sprockets and 
silent chains are used instead of gears. 

Kote the cam shaft turns the same direction as crank 
shaft when cam shaft is driven by silent chain. 

Example of Valve Checking on a 6 Cylinder Engine. 

As an additional check, use may be made of the fly wheel markings, as 

follows : 

Bemove the top cover and twirl between the 
fingers the long aluminum push rod (for the No. 1 
intake valve — the second rod from the front) while 
someone slowly turns the starting crank. Stop the 
engine at the exact point when the push rod is no 
longer free to turn and note the markings on the 
fly wheel. If the engine is properly timed, the line 
marked "IN-OP" near "TO l-|-6" wiU be di- 
riectly under the pointer. The exhaust valve is 
tested in the same way, except that the mark 
**EX-CL" is used to show the point at which the 
exhaust valve closes. The point at which the in- 
take closes and that at which the exhaust opens 
are not' shown, as, if the other markings for the 
same valve are correct, these are sure to be. The 
marks "TO l-|-6/' '*TC 2.|.5" and "TO 3-1-4" 
designate the top centers of the several cylinders 
and the timing of each starting from the proper 
top center is similar to that for No. 1 described 
EX-CL" each refer to the cylinders whose "TO" 

Fig. 3— Marki 
Marmon 34. 


above. The marks "IN-OP" and 

is nearest. Valve clearance on the Marmon is .003 


pafo 115 for converiion of deerees into inches 

„ *See index for valve timing of a 12 cylia 

tSee index for "repairing silent chains." 

16* ExbaoBt 
Valve Oloses 





Valve Timing "Indicator" or "Trammel." 
A trammel or indicator is a stationary starting 
point to base all work from. It is sometimes at- 
tached to the base of a cylinder or other point, in- 
stead of a center line on cylinder. It is usually 
directly over, or in front, of the fly wheel, as per 
fig. 4 (fly wheel indicator.) 

Example of 6 cyl. engine timing: inlet opens 
and exhaust closing at the same time, or on "top." 

When the long mark 1-6 is in line with "indicator" on 
crank case, pistons number one and six are at their highest 
points or upper dead center. After turning fly wheel to this 
mark, then turn the fly wheel to the left (when behind it) 
until the small dot mark is under indicator. This is the point 
(15") to set exhaust valve just closed. Therefore it is plain 
to see that setting the exhaust valve just dosing on a 6 cyl- 
inder engine with valves on the side, is all that is necessary. 

Fiff. d. — Ayeraire ▼•!▼« timing diaframs. 


Average Valve Timing. 

There is very little difference between the average timing of the four and the six 
cylinder engine. On the aix, the average inlet opoiing is 10.7 degrees past top center and 
closing point 37.6 degrees past bottom center. On the four the average for Inlet opening 
is 11.1 after top center and closing point 36.8 degrees after bottom center. The small 
difference would hardly be noticeable. 

The exhaust on the average six opens 46 degrees before bottom center and the 
four 46.3. The dosing point of sixes average 7 degrees after top, and the fonr 
7.7. Therefore, there is very little difference. 

On an average of engines, the intake remains open for a period of 205.8 de- 
grees, and the exhaust remains open for a period of 233.4 degrees. For an example, see 
chart 46, page 100, showing how long the valves remain open, or the period of travel. 
See page 542 for, ** setting valves of an engine where timing is not known." 

To Find Position of Piston. 

To find the top or bottom position of piston, see pages 320, 312. 

The beat procedure la to calculate the degrees from the center marks on the fly wheel, which 
are nearly always present either as punch marks, letters, or a simple line filed across the rim. If one 

Serson feels the tappet head of the valve which is bein^ checked, while another slowly pulls the 
y wheel round in its proper direction of motion, the precise moment at which the valve commences 
to lift can readily be determined by the binding of the tappet head against the stem of the valve. 

Converting Inches into degrees: — If the circumference of the fly wheel be then measured in 
inches by a tape line or its diuniotrr be aRcertainod and multiplied by three and one-seventh (which 
amounts to the same thing), the proportion of this measurement to the distance on the rim of the 
center mark from the perpendicular position will give the degrees of advance or retard. 

Suppose for instance, we And that the exhaust valve Just closes when the top center mark U 2 
Inches past the central line in the direction of rotation and that the circamference of the fly whMl 
is 60 inches. Now there are 860 degrees in a circle, and therefore by the simple process of multi- 
plying this figure by 2 and dividing the result by 60 we get the answer 12 degrees, which is of 
coarse the number of degrees represented by 2 inches. Also see page 115 for converting degrees 
into inches. 

ValTe timing on Dodge; first see that valve lifter or tappets are properly adjusted, which is 
.008 clearance for inlet and .004 for exhaust. Then turn crank shaft clockwise until top of piston 
No. 1 is 1-16 inch above top of cylinder on exhaust stroke. Turn cam shaft clockwise until No. 1 
exhaust valve is iust fully closed. Gears are then meshed. Dodge inlet opens 10* after top and 
closes 35* after bottom; exhaust opens 45* before bottom and closes 8* after top. FlywhMl is 
16^" dia. for ears using cone clutch and 15 V^" dia. for cars using the disk clutch. A degree on 
larcr \\hov\» a ilistnnce of 0.141H" an<l smaller wheel 0.1353". See page 542 for dia. of valves. 
































1 05 

2 09 

J 14 

4 19 

5 34 












1 07 

2 14 

■\ 20 

4 27 













1 09 

2 IS 

.1 27 


5 46 












1 11 


3 33 

4 45 













1 13 


3 40 































2 35 


4 71 













1 20 

2 40 

3 60 














1 22 




6 10 











1 12 
















1 14 


2 53 
















2 57 


6 15 
































5 31 













1 35 














1 10 








50 265 








1 11 

1 26 
















1 28 














1 01 

















1 17 
















1 18 





5 03 

7 40 
















































































































" / 





























































5 17 
















































































5 50 




















































69. U5 


























































1 96 





































































M 75.398 











4 19 



10 45 


n Table, Hi 


of an 

Inch to Sixty-Fourth 


0I..O2 . 1/S4 

.14 9/64 


,.27. 17/64 


) 25/64 




.64. 41/64 

.76, .n. 


.89 57/64 

03 1/32 

.15. .16. . 5/32 




). .41 .13/32 


3 1 


.65, .66. .21/32 



.90. .91.. 29/32 

04. .05.. 3/54 

.17 11/64 


..30.. 19/64 


8 27/64 


4, .55. .2 


.67 43/64 

.79, .80. 


.92 59/64 

05. m. 1/16 

.18. .19. . 3/16 


..32.. 6/16 


). .44.. 7/16 


6, .57. . 


.68, .69.. 11/16 

.81, .82. 


.93. .94.. 15/16 

08 6/64 

.20. .21.. 13/64 




i, .46. .29/64 


8 3 


.70, .71.. 45/64 



.95. .96. .61/64 

00. .10 3/32 

.22...... 7/32 


,.36.. 11/32 


r 15/32 


9, .60.1 


.72 23/32 

.84, .85. 


.97 31/32 

11 7^ 

23. .24 .15/64 




^. 49.. 31/64 


1 a 


.73, .74.. 47/64 



.98, .99. 63/64 

.12. .U.. 1/8 

.35 1/4 


. .38. . 3/8 


) 1/2 


2, .63.. 


.75 3/4 

.87. .88. 

. 7/8 

1.00 1 

This table is provided f< 

)r converting 

degrees into 


For instance; if a certa 

in engine is to be 

t;iDed when inlet opens, say 1 

0* after top 

of stroke, and 


are no marks on fly whe 

el to indicate this 

position, by referring to this 

table the dia 

tsDce in inch 

es to 1 

measure on fly wheel from 

upper dead center 

mark rso be found. 

It will be necessary hov 

ever, to knoii 

r the diamete 

r of th< 

B fly wheel. Suppose fly wl 

leel was 17 inches; 

refer to first column and find 

17, then go o 

ut to column 


10" and you have 1.48 (< 

)ne and forty-eight 

hoBdreths of an inch). Thii 
wheel ' 
• Forty-eight hundteths (.4 

would repre 

sent the dist 

auce to 

measure for the inlet op 

ening mark on fly 

8) is not so 

easy to mea.s 

ure on 

the rule, therefore refer to 

table below to .48 

and note it is equal to 81/« 

4 of an inch 


we woi 

lid have 1 31/64 of an inc 


Another Example: What 

, would 2H» 

repre8«'ni in 


on a 17 inch fly wheel 
Now refer back under 

1 Procedure: find 

17, go out to column under 2* 

* and we find 

.30. Put thi 

B down 

column headed 1* 

and we find .15. One-half of 
WLow and note .375 equals ^ 

this one doffr 

L'O would be . 

D7r. 'J 

MuH jKJdi'J to .:J0 oquaK .3 

7.'> R.-fifr to table 

1 of BU inch. 

CHABT HO. 61 — ^Table to Convert Degrees Into Inches. 
fourths of an Inch. (From Horseless Age ) 

Fractions of Hundredths into Sixty- 


FIRING ORDER: One, Two, Three and Four Cylinder Engines. 

f Firing Order of One and Two Cylinder Engines. 
There are four stro}2:es to ,two revolutions of the crank to complete a 
eycle operation, as explained in chart 29. 

A stroke of the piston means a travel from top to bottom or bottom to 
top, or 180 degrees movement, or one-half of a revolution oJE the crank 

There is but one power stroke during the four strokes^ or two revolu- 
tions of the crank shaft. Also note that the power stroke is a very short 
one; owing to the fact that the exhaust valve starts to open considerably be- 
fore pi&ton reaches bottom of its stroke. If the exhaust valve should open 46 
degrees before bottom, then the travel on power stroke would be but 134 
degrees instead of 180 degrees. 

Therefore, if there is but one power stroke to two revolutions of the 
crank shaft, we would have only 134 degrees out of the two revolutions, 
(or 720 degrees travel of crank) on which there is power. (See chart 46.) 

In aa engine with one cyUnder (fig. 1, chart 62), there is an explosion once dnilng 
•Very two revolutions of the cramc shaft, or in other words, there is one stroke of the 
piston when power is being developed, and three when there is no power, the piston 
^tien being moved by the momentum of the fly wheel. 

As the piston must be carried through the three dead strokes, it is necessary to use 
^ heftvy fly wheel, so that when it is started it wiU continue to revolve for a sufficient 
^^Iflie to move the piston until the next power stroke. 

There is vibration from a one cylinder engine on this account for the weight of 
^e piston sliding flrst one way and then the other has nothing to balance it. 

It can be balanced to some extent by attaching a weight called a ''counter balance,'' 
Cig. 12, chart 36), to the crank shaft opposite to the crank pin, in the same manner that 
tthe wheels of a locomotive are balanced, but even so there is vibration owing te power 
stroke at intervals. 

An engine with two cylinders: one piston can be arranged to slide inward as the 
other slides outward, so that one balances the other, as in fig. 4, page 118. This type of 
engine is called an opposed type of engine. Cylinders are set 180 degrees apart, also 
ertuik shaft. When one piston starts down on power stroke, the o&er would start 
down on suction, therefore referring to the scale under fig. 4, note there would be a 
fixing impluse at each revolution of the crank shaft or every 360*. There is stiU 
vibration, however, as the power stroke is not continuous. 

The two types of twin vertical cylinder engines, figs. 2 and 3, page 118, are ex- 
plained in text matter in the chart. Fig. 2 would cause considerable vibration, as 
would also fig. 3. 

The fly wheel of a two cylinder engine need not be as heavy as that of an engine 
with one cylinder, because it is required to carry the piston through only one dead 
itroke before another power stroke occurs. On 6, 8 and 12 cylinder . engines, the fly 
wheel is very small in diameter. 

The more cylinders an engine has, the more steadily it may run, for the explosions 
aiy be arranged to follow one another so closely that there is no moment when one of 
the pistons is not on the power stroke. 

**Firing Order of a Three Cylinder Engine. 

Three cylinder engine fires 1, 3, 2 from front of engine or 1, 2, 3 if from rear. 

The action of the fixing of a three cylinder engine is this: Taking three points of 
the circle (see page 119.) A at the top, B and C on each side below, the piston of No. 1 
cylinder is connected with a crank at A, to No. 2 cylinder at B and to No. 3 cylinder at C. 

t8«e pages 122, 181, 185. for firing order of 6. 8 and 12 cylinder engines. 

**Bttsed on exhauit interval being equal to 180 degrees travel. In actual practice it is more- 
Bee PMT* 100. 



Fixing Order of One, Two and Three Cylinder Enginae. 

Fig. 1 — Single ejUndcr engliM^ witli cnnkshaft s«t at 860**: There are four strokes of 180** on 
•U four cycle engines, therefore, there would be two reTolutions of 860* each, or 720* travel of crank. 
If the firing stroke started on top and traveled to within 46* of bottom when exhaust opened, there 
would be but 184* of the T20* on which the piston traveled on power. 

There is one power stroke (firing impulse), e'rer7 two revolutions of the crankshaft on one cylinder, 
four cycle engines — see diagram fig. 1, below. 

Single cylinder engines usually have counter-weights on the crank arms or fiy wheel to counter-bal- 
ance same. 

Fig. 2 — ^Two cylinder vertical engine with a 860* crankshaft: If piston of No. 1 cylinder is on 
power (P), No. 2 would be on suction (8) — see dianam below — therefore we would get an even 
firing impulse, or one during each revolution. But as both pistons are moving together, there would 
be considerable vibration, as both are on top or bottom at tne sam4 time. Oonnter weights are also 
used on the crankshaft of this type of engine in order to counter-balance. 

Pig* 8 — ^Two cylinder vertical engine with a 180* crankshaft: There are two firing orders of this 
engine, both of which would cause vibration. Refer to diagram and note first one. If No. 1 is on 
power (P), No. 2, would be coming up on compression (0), and would fire next. Therefore, there 
would be two firing or power impulses during one revolution, and on the second revolution there would 
be no firing impulse at all. 

With the other order of firing; if No. 1 was on power (P), No. 2 would be coming up on exhaust (E). 
tiM orank would therefore travel 640 <*, or IVk revolutloni with but ono firing impulse. 

Fig. 4 — Two cylinder engine with cylinders opposita and crankshaft set 180*: This type of engine' 
gives a firing impulse every revolution — see diagram below — it is mechanically balanced. 



Fig. 1 — One cylinder engine 
with a 860* crankshaft. 
Firing impulse every two 
revolutions — see diagram 


Fig. 2 — ^Two eyUnder ver- 
tical en0ne wUh a 860* 

Firing impulse every revo- 

Fig. 8 — Two cylinder var- 
tical engine with a 180* 

Two different firing orders 
— see diagram below. 

cyuNDER m 















P — means power stroke. S — suction. C — compression. E — exhaust. 
The "firing impulse," is the time combustion takes place at beginning 
of power stroke. 

cnmoER N9 



i - R^¥^Ltfri^t$ 





cufmffr m 













Fig. 5 — A three-cyliuder engine crank, 
set in throe positious or third of a revo 
lution. or 120 degrees apart. (S(>i> text 
for explanation, page 117j 

Fig. 4 — Two cylinder, opposed type 
engine with 180° crankshaft. 

Firing impulj>e 
every revoln- 
t i o n. Me- 
chanically bal- 




1^^ /fF¥^lUTH»ff 










CHART NO. iSa — Firing Order of One, Two and Three Cylinder Engines. 
Chart 54 on page 121. 



— Continued from page 117. 

No. 1 cjlinder will be at full compression, No. 2 cjlinder at 
two-thirds inspiration, and No. 3 cylinder one-third, exhaust 240**. 

No. 1 cylinder: The crank of this performs its half r^voln- 
tion, bringing it to position A', midway between points B and C. 

Whilst it is doing this, No. 2 cylinder is completing its inspira- 
tion stroke, and two-thirds of its compression stroke, and tb* 
crank is passed on to position B', leaving only one-third of a 
stroke to complete compression, and bring the crank to A, when th« 
firing of B commences. 

Meanwhile C is completing its exhaust and inspiration strokes, 
and has passed through two-th&ds of its compression stroke, so that 
wken No. 2 cylinder has completed its impulse, No. 3 has but to be carried over the 
saaO gap by the fly wheel, which gap represents the minus lap. 

Each of the three cylinders fire once every 720** (two revolutions), or 240** apart. 

No. 1 (A) fires and moves 240 degrees, which brings No. 2 (B) in firing pontion. 
No. 2 (B) fires and moves 240 degrees, which brings No. 3 (0) in firing position. No. 
I (C) fires and moves 240 degrees, which again brings No. 1 (A) in firing position. 

No. 1 (A) has now made two revolutions or 720 degrees, which completes the fou 
ifele evolution. 

The working stroke is 134 degrees, thertfore 240 degrees less 134 degrees equals 
IOC degrees, during which time no work is being done ( — 106* lap), that is, the fly 
wheel carries the crank 106*. 

Filing Order of a Four Cylinder Engine. 

Four cylinder engines are so arranged there is a power or flrlng Impulse every stroke, 
m two firing impulses every revolution, one beginning as the previous one ends. 

In order to complete the four cycle eyolutiona of suction, compression, ezplosiOB 
• nd exhaust for each piston, it is necessary that each piston have four strokes. As 1 
•aad 4 work together and 2 and 3 work together, then four strokes; two up and two down, 
m two revolutions of the crank shaft will give the complete cycle evolution for each pis- 
ton, with a firing order of either 1, 2, 4, 3, or 1, 3, 4, 2. (See diagrams bottom of 
page 116.) 

Tlia crank shaft of a four cylinder four cycle engine is always set at 180 degrees. 
(Bee pages 78 and 116.) 

Note the "throws" of a four cylinder crank shaft (see fig. 1, page 116); 1 and 4 
(end cranks) are in line, and 2 and 3 (inside "throws" or cranks), are in line — there- 
fere 2 and 3 are one-half revolution, or 180* from 1 and 4. 

The construction of the crank shaft would not permit the firing to be 1, 2, 3^, 4, be- 
when 2 was ready to go down on power stroke, 3 would have to be coming up 

on compression, but as 3 is always the same 
position as 2, then it could not be coming up, 
as it would already be up with 2. (See fig. 
1, page 116.) 

For the reason that 1 and 4 are together 
(up or down), and 2 and 3 are together (up or 
down), the firing order must be 1, 2, 4, 3, or 
1, 3, 4, 2. (See page 116.) 

A four cylinder engine could be made to fire 
1, 2, 3, 4, by having crank shaft made as per 
fig. 2, but it would vibrate excessively on ac- 
count of the rocking motion of firing from 
one end to the other. Therefore the firing 
order on all engines is arranged to decrease 
vibration as much as possible. The alternate 
distribution of impulse (firing) tends to 
steady the engine, as 1, 2, 4, 3, or 1, 3, 4, 2. 

Fi|^. 2. — Type of crank shaft which would 
permit a four cylinder engine to fire 1, 2, 3, 4, 
k«t is never used. 

Type in general uae, aee fig. 1, page 116. 

Cylinders are originally made to fire in proper order by the manufacturer, by setting 
the cams on the cam shaft (see fig. 2, page 116), and commutator or distributor wired 
to connect with the proper spark plugs (see charts 144 and 145). 

The order of firing depends on the ideas of the maker, and may be either, 1, 2, 4, 3, 
m 1, 3, 4, 2, on a four cylinder engine. 

Tbe eight "V" type of cylinder engine, uses a four cylinder 180 degree crank shaft 
with two connecting rods to one crank pin. See chart 36, page 78. 

Tbe twin six or twelve **V'* type engine uses a regular six cylinder crank shaft. This 
vfl! be treated farther on, together with firing order. Also see charts 62 to 65. 


L1f£ES ZSyn'y.TL.S 5rnSEB TEX. 

t^ La« W<h Cranli 
se Pwtch Harks 

Cantor*' Repl<»r« Ccci€ 

"^a Br f*-ap«r^ X^yoccd 

Fig. 3: Ulustration showing how the cam shaft with its cams are diiTen by a silent 
chain sprocket. Also note the ma^ on flj wheel in line with punch mark on crank case 
when pistons 1 and 4 are on upper dead center which thev are now, pistons 2 and 3 are on 
lower dead center. (Xo. 1 is next to timing gears) at this point, the setting of valves and 
gears are determined. 

For instance, if the exhaust must close say at 10' past upper dead center, then the fly 
wheel is revolved in the direction of rotation 10* from upper dead center. Then at this 
point the exhaust valve of No. 1 cylinder should just close. This is sulHcient as all other 
valves will be timed to open and close at the correct time. 

If the exhaust did not close at 10* past dead center, then it is either because the 
clearance of the exhaust valve tappet is set too close and holds the valve open too long, 
or the cam shaft gear is not meshed properly. (^See pages 102 and 112.) 

The firing order of above engine can be determined by obaervtng the position of the 
pistons and valves: Exhaust and inlet of No. 1 are closed; piston of No. 1 cylinder is 
at top of compression and will go* down on power stroke. Piston of No. 2 cylinder is at 
bottom of its intake stroke and will come up on compression; inlet valve still open and 
exhaust closed. Piston of No. 3 cylinder is at bottom of its stroke and will come up on 
oxhaust stroke; exhaust valve is open and intake valve is closed. Piston of No. 4 cyl- 
inrlrtr is at top of its stroke and will go down on suction; exhaust valve will dose within 
a 10* movement of crank shaft (note exhaust cam just leaving the No. 4 exhaust valve 
tappet), and the inlet will open immediately as piston starts down. 

Now to determine the firing order: If No. 2 will come up on compression as No. 1 
piston goes down, and if the power stroke follows immediately after the compression 
Htroko, then No. 2 will fire next. Therefore firing order must be 1, 2, 4, 3. The only 
othnr firing or<icr it could possibly have, would be 1, 3, 4, 2 — but this is impossible because 
No. ?/n ••xhnuHt valvo is open and it will come up on exhaust, then after exhaust comet 
piiirti(»n. No. W has just lire*], therefore No. 1 will fire next. 

A (pilck way to determine firing order of a four cylinder engine: when nose of ilrst 
(inil third c'lrii HnN't or exhaust) are on opposite sides of a shaft; engine fires 1, 2, 4, 8. 
Whpu lirnt uiid third rnniH are on the same side of shaft; firing order is 1, 3, 4, 2. 

Notn Oiitii Nliiin/i (ip<Tatf(I by silent chains and Bi>rockot8 turn in the same direction at the 
• iMiih uliitft nM'l Jii'it onco to Uw rrank twice. 

OaiiiN \i\ fl|(. 'J, pah'n 110 nro made ta open and cloBe exactly on a stroke of the piston or 180* 
Miii\ •ini'iil of riHiik, uliith m unusual in artuul practiro. 

On aliiivn cnHhin. nn. 3, t»u» rnjus ar»« Kot as in actual practice* for instunre. the above valvM 
o|.i.n iind i'lonn iim follnwH: Exhaust closes 10 dt'prcps after top. Inlet opens 6 de^eea after top. 
r.iiiaui.i opPUN fio •li«Ki«'i.« In.foro ))iHton iK at bottom dead center. Inlet closes 40 degrees after 
ImiIIi.iii itond r. Ill II- Tlir horc of cylindrrK is \\\ inchi'R diameter and the Stroke of piston is 4H inchea. 

Thit inaKn of above enalne is the Oolden Belknap and Swartz Oo.'s. model E-M 31, {^mt cylinder 
■ iitii xmUo ilKlnehnliht hrad ••iitfuie. Ilorse power Ih 22 V^ at t)o5 feet of piAton speed per minuta. 
PiodiwiN Mil It h. p, at 2, MOO r. p. m. on actual brake test and 31.9 h. p. at 2.000 r. p. in. 

Left fttid right bAiid Ttew of i modern type of six eyiixider enflae power plftnt. 

"Unit Power Plant/' meamng #iiffiiio, clatch, and transmlnion are all in one unit. 

OyUndsra are cast **!n block.'* Olatcb eBcas^d with fly wheel and disc type. Vafres **h" ifpt 
eaelosed GriiT control by "baU and udeket*' type of g-eftr shift lever. Q«tl«rator drireo from pmnp 
•hft/t. Starting motor driTtB rrank «baft. Note the apark plaga (8) are uaually over the Inlet Talyei. 

V«i* tke cama on tbli tbo **L'* typo engine are ail on one cam abaft. 0am gear meahaa with 
• ftsr OB crank ihaft. Note: * 'upper part crank case/' now known as "crank caae/* "Lower part 
■ ^ — rt«i" now known as "oil pan/ , 

^ VO. 64 — Bight and Left Side View of a Modem 81x Cylinder Automobile Engine. (Tbe 



Fig. 1. A six-cylinder engine with seven bearings to the crankshaft 
and cylinders cast in two blocks of three. 

Fig. 1. Note piston and erank 1 and 6 are in line wtth each 
other. Also 8 and 4 and 2 and 6. An end view is shown in fie. 2. 
Firing order of above is 1, 5, 8, 6, 2, 4. No. 5 has Just fired. No. 8 
will fire next, then G, 2, 4 — see illustration, fig. 2, for explanation. 

Bearings on the six cylin- 
der crank shaft are usually 
three, as per fig. 5, below. 

Sometimes seven bearings 
are used as illustrated In 
figs. 1 and 4. 

The right and laft hand 
_. . - ^ . , . . ^ crank shaft, referred to on 

Hg. 8. Counter balance weights page 128 are illustrated 

applied to a six cylinder crank below 

shaft with the result that the 

engine attains a speed of 2,500 

revolutions per minute without 

detrimental vibration. 

Fig. 2. This Is an end Tiei 
of crank shaft in fig. 1 lUnstra 
tion. Cylinders are in line witl 
each other, when in cylinders 
In this illustration they are sup 
posed to be out of cylinders 
hence not in line. 

The throws of a 6 cylinder craal 
are divided into three positions, oi 
120» apart. 

1 and 6 are always in line 
8 and 4 are always in line 

2 and 5 are always in line 
but they may be placed to th< 
left or to the right as shown ii 
figs. 4 and 5. 

On the above; firing order coul^ 
be 1, 5, 8. 6. 2. 4 or 1. 2. 4, 6 
6, 8. Assume that we are stand 
ing in front of engine; No. 5 hai 
just fired, No. 8 will fire next, thei 
6. 2. 4. 

£ / 

Fig. 4. A right hand 6 cylinder crank shaft, is determined by noting position the center throws. 
8 and 4 are to 1 and 6. If they are to the right of 1 and 6, as shown above and as illustrated in 
fig. 1, page 124, then it would be a right hand crank (view from front). 

A right hand crank will fire 1, 5. 3, 6. 2, 4 or 1. 2, 4. 6. 5. 8. 





Fig. 6. A left hand 6 cyliuder crank shaft; note 3 and 4 throws are to the left of 1 and • as 
illustrated, also in fig. 2, page 124. 

Therefore it would fire, 1, 4, 2, 6, 8, 5 or 1. 8. 6, 6, 4, 2. 

CfHABT NO. 65 — Crank Shafts of a Six Cylinder Engine. 



GINES. Rotary Valve and Rotary Cylinder Engines. Sleeve 
Valve Engine. Overhead Cam Shaft Engine. 

The Six Cylinder Engine. 
The variance in construction is principally in the addition of more cylin- 
ders and the shape of the crank shaft. 

The cylinders may be in ''pairs'* or in ''triplets" or "in block." The 
usual order is in two blocks, of three to a block. Cylinders on a six cylinder 
engine are usually "L" type. The cam shaft is shown in fig. 2, page 121. 

The six cylinder engine operates on the four cycle principle, the same as 
the four cylinder; in fact the general principle is used; the crank shaft must 
turn two revolutions during the cycle or four strokes. The cam shaft turns 
one revolution. The shape of the crank shaft of a six makes it possible for 
eaeh piston to complete the four strokes — see figs. 1 and 2, chart 55 ; note the 
erank shaft is divided into three pairs of "throws." Pistons 1 and 6 are in 
line ; 3 and 4 are in line and 2 and 5 are in line. A "throw" on a crank shaft 
is the part to which the big end of connecting rod connects and is really 
the "crank pin." Each pair of these crank shaft "throws" (1 & 6 & 3 & 4 
& 2 & 5) are placed 120 degrees or 1/3 the distance of a circle apart. 

There are six power impulses or explosions during two revolutions of 
the erank shaft, therefore the magneto armature* turns 1% revolutions to 
one of the crank shaft. When piston, say No. 1 goes down on firing stroke, 
it must make a full stroke or 180 degrees or % of a revolution of the circle, it 
eould not stop at 120 — see chart 57 for explanation, also fig. 2, page 122. 

A degree is l/360th part of a circle. There are 360 degrees to a circle. 
This mark, ® which is nothing more than a small "0" to the side of a figu**e, 
represents degrees. For the crank shaft to make one revolution, it must 
make a complete circle or 360 degrees. Although each pair of "throws" of 
the crank shafts are placed 120 degrees apart, this would place one pair, say 
pistons 4 and 3 at A, another pair pistons say 5 and 2 at B, 6 and 1 at C. Each 
piir would be 1/3 the circle apart. 

There are two kinds of six cylinder crank shafts; left hand and right 
hand — see figs. 4 and 5, page 122. The cylinders usually Jfire on a right hand 
cmik 1, 5, 3, 6, 2, 4, while on a left hand the order is usually 1, 4, 2, 6, 3, 5 — 
lee pages 124 and 122. 

The number of bearings for the six crank shaft may be 3, or 7. Three 
l^carings is the usual number. The carburetion. A six cylinder engine us- 
^y requires special intake pipes and double or multiple jet type of carbure- 
tor to meet the demand of the multiple of cylinders and distance the car- 
lotted gas must travel. The timing of six cylinder valves is identical with 
ftat of the four. The process is goi\e through with just in the same manner. 
It is only necessary to time with the exhaust valve closing on the first cylinder 
•ndthe "L" type, and on "T" head type, with exhaust valve closing on ex- 
lutnst side and inlet opening on inlet side. 

If the reader will turn to charts 55, 56 and 57 the explanation of tlie six 
blinder engine will be made more clear. 

tSM Dyke's worlcinff model of the six cylinder engine. *If a timer and distributor, they tnm 
^ rttolnUoQ to the ersnkg two, or tame aa the cam shaft. See index *' ignition timing." tSee foo^ 
■Mi hottom of page 70. 

*See "Specificationa of Leading Cars." page 544 for rnrs using 6 cylinder engines. 

IThtro aro four ttandird firing orders of a six cylinder engine. Read matter under figs. 4 and 
y »tge 1S2. 



.-. - ■■ a: 


r» :h#v are 

..i KJU'.a Crank. 

>. >. ^:*!0N NTMBER ELEVEN. 


■ "I ♦ 

' orxier. I. 4. 'J. 6. 3. 
': 4-# I ;l. 5. 6. 4. 
No"' I »iarts down on firing, No. 4 would fire next, then No. 2. then 6, 3 and 5 in their re- 

cet «ccond flrlDg order (1, 8, 6, 6, 4, 2.) start with No. 1. then No. 3. 5. 6. 4 and 2. Note 
*.in>osod to be from the front of engine. 




t4B <ap 


1 loll. 

on iJown 

1^1 «r a 


trvig 1 
<ta*art ■trot* 



OB dan 



An end view of the Ohalmers ilx cylinder engine ("6-30") is shown to the right. The firing 
order of this engine is L, 4, 2, 6, 3. 5 — ice the top row in table to the left. 

This illustration is shown, in order that the reader may see just how the pistons are all in line 
when in the cylinders, instead of being out of line as shown in the exaggerated dr^iwings. flgi. 1 »nd 3. 

Timing Ohalmera v&lves: Turn the fiy wheel, bringing tho mark "Ex. CI." (cxhauat eloces) 
on the fly wheel, exactly in line with the centered reference mark pointer on tho rear of the crank 
case. With the tiy wheel mark in this position, the exhaust valve on tho No. 1 cylinder ihould Jast 
close. If not. adjust the exhauit cam so it is at the closing point. 

It is e^iHcntial thnt these adjustments shall always be made with the "back la.^h" or lost motion 
in the driving gear entirely taken up in the same direction, that i^. in the diriM-tion of the rotation 
of tho engine when runuinj:. 

GBJiMT NO. 4'iO^Two Firing Ox^ex^ of a Six Cylinder Engine Explained. 



sue 7 1 ON 3 T ft one 

fltii«4 ctuntM 




^tuiftt eenrc* 


riC. 1. — ^BaUUve position of PlBtons on a Six Cylinder Engine. View of illastrations are in front 
of engine — hence cranks are rotating to tlie right. 

Note pistons must make a full stroke, up or down and crank throws must travel 180* 
at each stroke, or % revokition just the same as a four cylinder. 

In order however, to show how and when the cylinders can fire 6 times during two 
xemliitlons of the crank shaft— the above illustration and the firing table in Chart 56 
is provided. 

The pistons must go from the extreme top to the bottom at each explosion or stroke. 

♦Fig. 1 — If 1 and 6 pistons go down on say, firing stroke, then they would go to bot- 
tom "1-6 N down," which is a half revolution of the crank or one stroke or 180*. 

Then pistons 2 and 5 would be at dotted line position ''2-5 N;" 3 and 4 pistons 
wodd be at dotted line position "3 and 4 N." 

Therefore we have an ''over lapping" of strokes — see Chart 58. 

Only two of the six cranks are on dead center at the same time. The firing point 
is at top. 

Fig. 2. — ^Note position of 2-5 and 3-4 after 1 and 6 have just made a half revolntion 
or mctlOB stroke down. They have both moved 180**. Also note that as 3 and 4 passed 
the top, or firing center, either 3 or 4 must have fired. 

Fig. S. — 1 and 6 have now made another stroke up, on compression, (stroke No. 2), 
or 180* more or 360* in all, or a revolution. Note 2 and 5 passed the firing point during 
this stroke; therefore either 2 or 5 must have fired. 

Fig. 4. — 1 and 6 have now made another stroke down on power and fired, (stroke 
No. 3) or 180* or 1% revolutions in all. During this stroke, 3 and 4 passed the firing 
point again and one or the other must have fired. 

Fig. 5. — 1 and 6 have now made Its fourth stroke, up on exhaust, or another 180* or 2 
rerolntions in all. During this stroke 2 and 5 passed the top center firing point again, 
and either 2 or 5 fired. 

Note we have followed out the four strokes, during two revolutions, and during the 
four strokes, there were 6 explosions, or power impulses, as the pistons passed the top. 

A six differs from a four cylinder engine, only in the shape of crank shaft, which is 
divided into thirds instead of halves. 

*Mote when 1 and 6, or either pair go down or up; only one of the pair is on firing or compression. 
Beth eonld not be on firing at the same time. (See Chart 56). However, in order to explain how the 
cranks travel in pain we will not state which one of the pair is on the ahove mentioned stroke. 

HO. 57 — ^How the Six Cylinder Engine makes Six Impulses during Two Bevolutions of 
tbe Crank Shaft 



t^rOU STBOKf'r^UtPW STlWWt»T^PlStWST40*E»J|WSTM| 3TW»t*4^ 

}4»1 »4tf! 

;^*j Fiff. I.— ["■; 


4 Cyllndar Iiap> 
On ft 4 ey Under englno there are four 
periods of 46° travel or 1S4** in all^ during 
tke four strokea that there is no power. 

Bef erring to iUuatrationp %* 1, note^ if pii- 
ton No. 1 is firing^ it does not travel its full 
stroke with a crank movement of ISA* on 
power, because the exhaust valve starts to 
open J say 46" before it reaches the bottom 
ji*5 of ita stroke^ therefore it really travels but 
134* on its power stroke. CoBsequently, be- 
fore next piston £res there is a gap of 46*. 

Therefore, in a four cylinder engine there 
are: 4 periods of 134* 'when 1 cylinder is 
firing or working and 4 periods of 46* when 
no cylinder is Bring or working. 

_ The fly wheel must take the pistons 

' ; ^ ,1 over center durine the * ' no " working 
'■^'■^'^'^ strokes. 

O Gyllnder Lap. 
On tbe Btx cylinder engine ^ each pis< 
ton is working on 
all of its stroke of 
180' except 46*^ 
leaving 134* «e- 
tually working. 

Th^tf second eyl- 
inder to fire, starts 
to work 120* after 
the first starts to 
work, and works 
14* before the ex- 
haust opens or tho impulse ends 
on the first cylinder. Gonse^ 
quently there is no idle spaoe 
between the firing of cylinden, 
but quite the reverse, for there 
is a lapping of power strokee. 

There are 6 perioda of 100* 
travel when one cylinder la work- 

ing alone and fi periods of 14* travel when two cylinders are working together. 

Therefore 7*0Oths of the time 2 cylinders are working together and 63-$0ths of the tfnie 
1 ey Under is working alone. 

Eight Oyllnder I<ap. 

Tlie eight cylinder V type with eyliuders 90° apart; when one cylinder is firing LI 
travels the same as the four; 134" on power when the exhaust ^starts to open, say at 44* 
before bottom of its ISO"" stroke. 

The second cylinder starts to fire 00' after the first, and moves for 134* before ita 
exhaust valve starts to open. 

Therefore there are, during the four strua«ffi, 8 periods of 44* travel that two pistou 
am working together. 8 periods of 46* travel when one piston is working alone. Tbeirt- 
fore 22/45 of the time two cylinders are working together and 23/46 of the time one 
eylinder ii workiiig alone* 

la Cylinder I»ap. 
The ISB eyUnder T type or twin six^ when one cylinder is firing it travela the sam^e 
■i those previously described; namely; 134* before the exhaust valve opens, it then eon- 
ttnnee on for 46* more, till it reaches the end of its exhaust stroke. 

When the first cylinder fires, and piston has traveled only 60% the second cylinder firea 
mad joins No. 1; they then work together for a period of another 60* when the third eyl^ 
tnder fires and joins No. 1 and 2, Now No. 1 has still 14* to travel yet befere its exhaust 
▼al7e opens, so consequently the 3 work together until that occurs. 

At the 134* point No. 1 cuts out and Nos. 2 and 3 work together for a period of 46* 
when No. 4 fires and joins them and so it continues throughout the cycle» See page 134* 

OBAXr NO. 68— niiistxatliig the *'Lap" of Power Strokes of a 4, 6, 8 and 12 Oyllnddr BBflB% ^ 
tAe 8 mnd 12 h^ng of the **V** type. Note, the above diagrams are based on the thMij ': 
tAMt tie mxbAUBt opena 46* before bottom. Also note that diagrams are not drawn to aemla. ^'i 



*The Eight Cylinder "V* Type Engine. 

AAwmntmgm of miltipie cjlinder engines: 
"flezfbUity" of eontrol, meaning qniek 
■eeelention or quick pick ap of the engine 
from Blow to f aat speed, the absence of gear 
■hifting, and a more perfect control are 
tke features of the six, eight ''V" and 
twin six engines. The more cylinders fir- 
ing or lapping, the more flexible the control. 

The eiglit cylinder engine is commonly 
known as an engine with eight cylinders 
placed consecutively in line over a crank 
shaft having eight "throws" or crank pins. 

The simplest arrangement of eight cylin- 
ders would be all in line just as the six or 
the four are arranged. Bat this would be 
impracticable, due to the extreme length 
aad also to the abnormally long crank 
■haft which would be necessary, while the 
erank case for such an engine would be very 
heavy. To get around these difficulties the 
ejlinders are arranged in two sets of four 
•pposlte to each otlier at an angle of 90** 
in tlie form of a V. 

ffr^yfc- ahaft: Arranged in this way, the 
sight cylinder engine is no longer than a 
four cylinder one of equal bore. As com- 
pared with a six, it has about 30 per cent 
Isaa length, resulting in a shorter crank 
tmn a weight reduction factor. In addi- 
tiim, its crank shaft is of the samo form 
mm that of a four, the throws being all in 
one plane; whereas those of a six crank 
■hmft are in three planes, and is a simpler 
■maufaeturing job. Furthermore, the shorter 
mkmft is less given to periodic vibration. The 
caiB shaft is also shorter and less prone to 

Cylinder and connecting rod arrangement: 
Where cylinders are "opposite," this 
Mffffw the conecting rod lower end is at- 
tnehed together as shown on page 129, and 
tamed, "yoked" together. The connect- 
hsg rods on one cylinder in line with con- 
aeeting rod on opposite cylinder. Where 
flinders are "staggered," this means the 
lewer end of connecting rods are not to- 
gether but are "side by side" on the same 
crank shaft bearing, (fig. 7, page 74). 
This naturally necessitates the cylinders on 

one side, being placed a little to the side, 
or not exactly in line with opposite cylinder. 
and termed "staggered." 

The cam shaft on the eight V engine may 
be one or two. the majority use one cam 
shaft. The Cadillac uses a cam shaft with 
eight cams operating the sixteen valves, 
whereas the Cole and King eight V engines, 
use one cam shaft with sixteen cams: one for 
each valve. 

Lap of power strokes of an eight cylinder 
"V" type engine: The explanation of the 
lap of the firing impulses is given in chart 
68. This shows that during eight pt^riods 
of 44* travel, there are two cylinders work- 
ing together on power, whereas on a six, 
there are six periods of 14* travel, when 
two cylinders are working together. 

This chart also shows eight periods of 
46* travel, when only one cylinder is work- 
ing alone» whereas in a six there are six 
periods of 106* travel where one cylinder 
is working alone. 

There are eight power impulses or ex- 
plosions, during each cycle of two revolu- 
tions of the crank shaft. In other words 
the four strokes or two revolutions, is just 
the same as in a four, but there are eight 
power impulses or explosions during these 
two revolutions. There is a power im- 
pulse every quarter turn (90* movement) 
of the crank shaft, and thus there is no in- 
termission between them, but rathor as 
"overlapping" so complete that the turn- 
ing effort is practically constant. 

In the six cylinder engine, there is a 
power impulse every one-third revolution 
of the crank shaft, and though there al- 
ways is a turning effort upon the crank 
shaft, it has more fluctuation, due te the 
longer interval between impulses. 

In the four cylinder engine, an impulse 
occurs every half revolution, and ob- 
viously there are periods in the cycle when 
there is no appreciable force extorted by 
any of the pistons. The fly wheel then 
is called upon to carry the shaft over these 
power lapses. 

The Cadillac Eight. 

As an eTample of an eight cylinder en- 
gine and its constmctlon, the Cadillac make 
will be shown in the charts following. 

Although a later model Cadillac is model 
S5, and 57, the model 51 and 53 will be 

shown in order that the reader may note 
the variance in construction or improve- 
ments. The improvements of the model 56 
are mentioned. 

•See page 644; "Specifications of Leading Cars," for cars uf^inj; eiKht cyliiulcr <'i;;:iiu:s. 

: 1918, BUldel 67 engine; 8 cylinder "V" type engine is same bore and stroke as form»Tly; 
%%' bore by 6%" stroke; piston displacement 314 cubic inches. Cylinder heads now detachable. 
Il ii BO lenger aecoeesrj to remove radiator to take out water strainer between radiator and wator 
" I p«ae ^ '^ Oftdillac clntch and pages 130 and 730 for water thermostat and con«\«n%«T. 


A/^H T 31 OC^ 



the front end < 

eight cylinder engine. There^ 
are two groups of cylin- 
dertt^ each a block casting 
of four cjlinderSf mounted 
at 90 degretm to each other 
ou aa alumitium crank ease. 
The cyUndera are 3H inch 
bore and 5% inch stroke* 
The piston displacement is 
314 cubie inches; the horse- 
power rating is 31.25. In 
dynamometer tests the en- 

fine shows 70 horsepower at 
400 r. p, m.. The crank 
shaft is indentical in de- 
sign with that used in a 
four cylinder engine, and 
the cam shaft carries the 
same number of cams as in 
a four cylinder design. This 
engine weighs approxi- 
mately 60 pounds less than 
the four cylinder ^adUlac 
engine of equal horsepower. 
There is but one carburetor 
used, — ejtplained further on. 

Bach of the two cylin- 
der castings contains fonjr 
I«-Bliaped cylinders. The iu^ 
take valves ar'e tulip 

The exhaust valves are conventional poppet shape. Over each cylinder bore is a remov- 
able cap which gives access to the water jacket and to the combustion chamber. Between ths 
second and third cylinder in each block the t breather pipe is brought up through the cylin- 
der casting. In rear o' the fau is the power tire pump for tire in^ationJt 



J^rr , 






4# t^ 




Fig. % Gross section of 
Cadllac eight cylinder en- 
gine with the cy Under 
mounted in two groups of 
four cylinders each at an 
angle of 90 degrees* The 
single cam shaft is located 
direct above the crank shaft, 

ftad the means whereby one cam operates the two intake valves for the opposite cylinders is 


Fig 3. The Talve operating mechanism of the Cadillac engine, showing how one cam 
operates two opposite valves. The cam bears against the rollers in the ends of the small 
arms, which are pivoted to the [tiate above, and which are interposed between the ends of 
the push rods and the cams, so that the lift will be straight upward instead of having a 
side thrust component. Adjustment of valve clearance is obtained in the usual way by 
lengthening the tappet. The upper part of the tappet screws into the lower and the two 
are locked by a nut. The position of the cylindersj make the valves extremely accessible, 

*Note: The tulip ibApc>d inlet vsWe wmi uied on tomo of tbe atrly model 51 c«ri, bat sot od othM 

_j^l ftnd &S tlie ens^lne breathert are between the teco&d and third cylindcrt om ss^b 
^^ ^" ^or oil. On Tn»« *fi brestliert sr* on valve cover platei; and oil fitlerv ara 







IkAftlBc ijstem in the Oadillae eight cylinder engine. Bhowing the nse 
if tw» tilent chuins. one driving tho cam ihaft and another driving from 
lk» CU& shaft to the shaft driving the Delco system. The tire pump \% 
Mfim by spur gear. There are two water pumps on the cross shaft below 
Aft erwik ahaft. and this shaft in turn drives the gear oil pump in- 

Note the sbiirlA cub 
shaft used in eight cyl- 
inder Cadillac engimea. 
On it are eight carna 
which operate the six- 
teen valves (eight inlet 
and eight exhaust 
valves). Each cam works 
two valves through the 
rollers shown on oppo- 
site sides of it, (fig. 8, 
page 128.) The shaft 
is earied on five bear- 

Another make of **y" 
type engine: The Davis, 
uses two cam shafts. Thia 
permits the direct opening 
of Talvea without the rock- 
er arms which are shown in 
fig- 3 page 128, between 
oams and tappets. Alao 
permits any desired timing. 

The timing of the Davia is 
as follows: 

Inlet opens 10* after top 
and closes SO* after botton. 
Exhaust opens 46* before 
bottom and closes 6* after 

See page 132 for Cadillac 
Ignition timing. 


Crank shaft: A three-bearing crank shaft is used, with the 
throws at 18U degrees, as in a H>ur eylinder design. (See flg. 
5, page 78; connecting rods are "yoked" however.) Two con- 
necting rods attach to each crank pin. this being possible by 
having one connecting rod with a split or forked lower end. and 
the other a single end to fit between the forks called "yoked'* - 

aaswins how the two connoct- 
Bf rods are attached to one 
■BTfnf The outer rod fastens 
• tho oater ends of the split bush- 
■f (J) with a two-bolt cap for 
•eh arm of the yoke. 

Tho boshing is fixed to this rod 
ry piaa. The other rod goes be- 
vecB the two arma of the yoke, 
s ahown by the dotted outline. 
Wa iaaer rod is free to move on 
he bnahiog. Therefore, the bear- 
Bf for the yoke end rod is the 
iBor anrface of the bushing 
gaiast the shaft, while that of 
he tamer rod is the outer surface 
f the bushing. 

011 1'i'iJin 

Lubrication of tlie eiirht cylinder Cadillac engim-: The 
pump draws the oil iii» from the reservoir and forces it through 
the pipe running along the inside of the crank case. Leads run 
from this pipe to the crunk shaft main bearing and thence 
through drilled holes in the shaft and webs to thi- rod bear 
It also is forced from the reservoir pipe up to. the pressure valve which maintains a uniform 
abore certain speeds, and then overflows from this valve to a v\ve extending parallel with and 
h«rc the cam shaft. Leads from this latter pipe carry the oil by gravity to the cam shaft bearings 
ad chains. Piatona, cylinders, etc.. are lubricated by the overflow thrown from the rods. 

IBT irO. 00— Parte Of the Sight Cylinder "V" Type Engine (Cadillac); Crank shaft, Ck>B 
aeeting rods, Lnbrication (model 51). Tho mo<lc].s 53 and 55 are similar. See separate 
arrangement of generator and distributor on j)n^o 132. 



y^ ik Oi^t«3t tkovtns the general Arrangement of the fuel, water and flsha.U8t systems of the 
dtec -iiaiwif r*i«;« mrv two exhansta and two mufflers, one for each set of cylinders; while the gaso- 
■:b# > «sa >« vr«««'zry to the carburetor which is between the two cylinder blocks. The air pressure 
;k*w4» ror rurvat^ \it t^tl f* at the front of the engine. There are two water pumps and two sets of water 
cvaa^uwiA ^r t^ radiator. 



mj AbB^ to» ^ tnanlf old 









rtg 2. — *Thermostat principles of water 
mt^Sil: A housinic containing a syphon 
U^ostat and a valve controlled by the 
thermostat, are located on the cover of 
each water pump. 

The thermosUt (A), fig. 2. is accordion 
shaped. It contains a liquid which is driven 
Into gas when heated. The resulting pres- 
sure elongates or expands the thermostat, 
forcing the valve (B) from its seat. 

A drop in temperature changea the gas 
back to a liquid, reducing the preasure In 
the thermostat and allowing it to contract, 
thereby bringing the valve (B) back to 
iU seat. 

This valve on thermostat is placed in the 
line of circulation of water, to the side of 
pump (2A). When cold, the thermostat 
Talve (D) is closed thereby stopping circu- 
lation When warm it expands and opens 
valve (B) which permits pump to draw water 
from radiator. 

A hand control connected with a shaft ex- 
tending from cover of pump, is also provided 
from seat, which can raise this valve, in 
order to drain radiator. 

On the Cadillac model 66 and 67, the 
water circulation pipe (0) ia through Jacket 
of inlet manifold. On the Packard this 
thermostat is placed directly at top of radia- 
tor (rear) and principle is the same. 

Condenser as used on Cadillac — see page 
throttle by means of the connecting rod '*P.' 


To adjust carburetor: l — Open the throttle about 
2 inches on the steering whei-1. Place the spark leTer 
in the "driving rsnge' on the sector anl start the 
engine. 2 — Run the engine until the water jacket on 
the inlet pipe is hot. 

8 — Hove the spark lever to the extreme left on the 
sector and the throttle lever to a position which leaves 
the throttle in the carburetor slightly open. Adjust 
the air valve screw "A" to a point which produces 
the highest engine speed (see note 2). 

4 — Close the throttle (move it to the extreme left 
on the sector) and adjust the throttle stop screw "B" 
to a point which causes the engine to run at a speed 
of about 300 revolutions per minute. The spark lever 
should be at the extreme left on the sector when this 
adjustment is made. 

6 — With the spark and throttle levers at the as- 
treme left on the sector, adjust the air valve serew 
**A" to a point which produces the highest engine 

Dash pot principle: The cylinder **0** on the 
carburetor bowl contains a plunger operated by Ike 

^, .„_ „ When the throttle is opened, the plunger is forced iBt« 

the gasoline in the carburetor bowl. The plunger is drawn out of the gasoline when the throttle U 
closed. The object of this "throttle pump ' or dash pot is to force gasoline through the spraylaf 
nossle when the throttle is opened quickly for acceleration and to assist in starting in extremely OM 
weather. When the throttle is opened slowlv, the plunger has practically no effect on the amount tl 
gasoline passing through the spraying nosile. 

Note 2. — Turning adjusting screws "A" or "Q" in a clockwise direction increases the propoitfM 
of gasoline to air in the mixture. Turning either in a counter clockwise direction decreases the pro- 
portion of gasoline to air. 

OQBABT NO. 01— Cadillac Carburetion. Thermostat. (Model 61, 63 and 66 cars.) 
•See pajrefi If*". l^'-> «"<i "l-"" *">^- 





2@— :^ 

40 R 

Rie^a HOC It 

FW3NT or cnatMc 


Yiff. 1: Diitribator connections. Fig. 2: Firing order. 

Fig. 2: Firing order of Cadillac Model 53 and 65. Cylinder 
then 2B^ 3L, IB, 4L, 3B, 2L, 4B. Or follow out tho black figures 
whieh show consecutively how cylinders fire. 

Fig. 1: Distribator 
connections on the 
model 53, 55, OadillM 
— ^Delco ignition sj»- 
tern. The cables lead 
from connections on 
distributor to the cyl- 
inders in the order 
which they fire. Note 
the brush **B'* makei 
contact consecutively, 
but cables from the 
distributor are con- 
nected to the plugs in 
their respective firing 

marked (IL) fires firsti 
on the side of eylinden 



V /^REA»T 

prSTON / V 
con. ROD ^ 


^f 7 


\cilAnt^ 5»«M~r / 



nc. a, 7 * 8; Cadillac— Delco distributor 
Md Timer — movement shown in deg^'ees. 
Tktre ifl an impulse or firing spark at every 
90* movement of crank shaft, which is % 

: af a atroke of piston, or ^ of a revolution 

; af ermnk. 

Fig. 10: Relative movement of platona: 
By observing piston No. 1, which is now ready 
to start down on its power stroke or jut 
commencing its working stroke, it can be 
seen just what is taking place in all the 
other cylinders, by referring to the following: 

crank trayels 00*, the timer or dis- 
tributor brush (B), being run at cam shaft 
then moves 45". 

crank makes two revolntions or 720* 
tka timer and distributor brush (B) moves 
!!•* or one revolution. (See Dclco system 
£« explanation of the ignition system used 
^ tUa engine.) 

'oro tliore are 8 sparkf to two revolu- 
of crank. 

IL — Starting to fire. 

3L — Starting to com- 

4L — Starting suction. 

2Ii — Starting to ex- 

2B — Compressing. 
IB — Suction. 
SB — Exhaust. 
4B— Working. 

Two pistons on tho right (when facing en- 
gine), are all the way up and two all the 
way down, while all four on the left are 

KO. 02 — Oaiillac Bight Cylinder V Type Engine. Firing Order and Relative Mora- 
BMnt of Pistons, also the Distribator to Crank Shaft. (Model 53 and 55 car.) 

1m \im. note (tn page 134 explaining which \% Ihc x\i\\\ si<N' of an iiiitoriiohilf' nr r'n<ririf. 



FIG. 9- SjDE viEvy NOm 

TdH IO.Di5TBIBMTn43 «A0 T|FprB 

The object for using two con- 
tact points on the timer is to 
distribute over two sets of 
points the rarrent which would 
otherwise pass through one. 
This greatly lessens wear and 
burning of the points. Inter- 
rupter is the closed circuit type. 

OadlUac Ignition System. 

The dlstrltiiitoi uid timer (flg. 10) are carried on the fan tka^ft 
housing, ant! arq^ driven tlirmigh a nH of tpiral i^oafs Attached to tba 
fan «lmft. Tho dJHtributor consii&ta of a cap or head of inBulalUic ma- 
teriai, cArrysn^ otm contact in the center with tight additiQaal coiaiaeta 
plectid at equal diBtAcires about the cM<iier and a rotor which maiataltia 
constant comEHunicatioTi with tl^ne center coittaet. 

The rotor carried a rontaft button which aervea to close the aecijadarjr 
circuit to the spBrk plag iu tho proper cylio^Jer- 

B«n€at]] tlie distributor head ftnd roU>r i& tbe tlm«r. The Itmar eaa 
is provided with a lock screw in tbe eenier of the shaft. {See if. 1 1.) 
A tiiatiual Apark control Is prc^vided m addUlon to the automatic apark 
contrnl. Tht manual spark control U for the purpoae al iecuring %h« 
proper igniition control for v&nable rondUEonii, aunh at startf&c. dtf< 
rereiiri>s in gaaoHne, weather con d it lone and amount of carbon m tht 
engine. The automatic control is for the purpose of securing the p fop sg 
ignition control necessary for the variation due to engine speed sUm*. 
The timer contact points axe set as follows: Turn the engine orcfr 
until the contact arms "D" & "0" are directly on top of lobes of the 
cam "B." Then adjust the contact points at "E" and "F" f tkmt 
they stand twenty-thousandths of an inch apart. Both sets of eoatoet 
points should be adjusted alike. 

To time the ignition proceed as follows: Move the spark lerer to 
the extreme left on the sector; open the compression release eoeke •• 
the cylinder blocks, and crank the engine by hand until the piston in No. 1 cylinder is on firing center. (Ho. 
1 cylinder is the one nearest the radiator in the left hand block of cylinders.) 

*Next remove the distributor cover; also the rotor, and loosen the lock screw A just enough to oDow tko 
cam "B" to be turned by hand after the rotor is fitted. (The lock screw should not be loosened enon^ tO 
allow the cam to torn on the shaft when the engine is cranked by hand.) 

Then replace the rotor and turn it by hand until the distributor brush in the rotor is directlj fm^m 
the terminal marked No. 1 on the distributor cover. Replace the distributor cover, and move the spark Uirm 
to the extreme right on the sector. 

Then switch on ignition ; hold the high tension wire to the spark plug in No. 1 cylinder about iBO* 
eighth of an inch away from the cylinder easting and turn the engine slowly by hand in the direction Ib 
which it runs. Stop turning immediately a spark occurs between the wire and the casting. (It will bo 
necessary to turn the engine nearly two complete revolutions before the spark occurs.) 

If the cam "B" is properly set a spark will occur when a point on the fly wheel one and tw«nt7-0BO 
thirty seconds of an inch in advance of the center line for No. 1 cylinder is directly under the polalor or 
"trammel" attached to the crank case of the engine. Tltis point for each cylinder is marked on tho fly 
wheel by the letter "10/ A." 

If the spark occurs before this, rotate the cam "B" slightly in a counter clockwise direction to oOf TOO l 
the adjustment. If a spark occurs later than this, rotate the cam slightly in a clockwise direction. 

After the adjustment has been properly made, lock the cam securely to the distributor shaft bj tho 
lock screw "A," 

After locking the adjustment it is a good plan to check the timing by fully retarding the spark loTor; 
in other words moving it to the extreme left on the sector, holding the high tension wire to the spark ploc 
in No. 1 cylinder about one-eighth of an inch away from the cylinder casting, and again turning the OB- 
fine slowly by hand in the direction in which it runs, stopping immediately a spark occurs. 

If the ignition is properly set the spark will occur under these conditions when the center line oa 
the fly wheel for No. 1 cylinder is directly under the pointer attached to the crank case, or has passed tto 

Oantion: Do not set the ignition so that the spark occurs before center with the spark IsTor at Iho 
extreme left on the sector. 

Resistance unit and Ignition coil are explained on pages 378 and 246. 

OHABT NO. 62A— Ignition System of Type 53, 55 Cadillac — see page 896 for wiring dimgrsa 
which is also wiring diagram of typo 67 Cadillac. 

*8eo page 878 — adjusting Delco timer. See page 729. fig. 7. "te»t-ligl>t" for ignition timing. 
Chart 68 omitted — error in numbering. 



•iBifle uatt ifstfliD — the fmrno af thi.' 
etf b#i»f u«ed 40 carry the return 

Q-o,t fide ot ihn ^eaerator, 
•lo7«fft batr^r^, lamps, lioi'a 
EUd i^JligrQ &pp»ratu3 H 

Mime part of tbe fjrftme of 
ea? or engiue, Th? 
oliuit conncftloaa »rij mide 
with eopj'Cr wiri^s or tablcA. 
&i« lustra rt Ion 2 SB, page 
ail for furtltvr BipUDatioo. 

TBMNrW LI6MT - «V. '4 €» 

■tut Ihfl QIJ- 

Be iiur« Ihat 

Ul4 trikQAraLOuBioa coo- 

treJ leTftr ii in 

**wmtT9l** pOftition 

a&d tbal tha b*od ^ 


Note the preBture of air in the gasoliDo tank. (This is indicated by the "air pressure gnage'* on 

Ike dash.) If the pressure is less than one pound, it should be increased to that pressure by means of 

the **liftad air pump." After the engine ia started the pressure is automatically maintained. 

Place the spark lever in the "driving range" on the sector and the throttle lever about two inches 
a the extreme left (see note). Move the ignition switch lever down, thereby switching on ignition. 

Umb push down on the starting button. This will bring the starter into operation and will cause the 

«fiBe to "tnm over." 

In cool weather (also in warm weather, if the engine has been standing for some time), pull up the 

"MBlUary air valve lever" before you press the starting button. 

Am aoon aa the engine fires and commences to run under its own power, which should be in a few 

nw mda. remove your foot from the starting button. 

If the "anziliary air valve lever" ia pulled up when starting the engine, it should be "pushed down 

akaot one-half the way" immediately the engine is started, and all the way down as soon as the engine la 

ma WiWigll to permit doing to. Note. — if you crank the engine by hand, place the spark lever at the 

MtroBO left on the sector. 

In astrmely cold weather, if the engine is not started in 15 or 20 geconds, remove your foot from 

iko starting button. This will stop the cranking operation. Now open and close the throttle once or twice 

with the hand throttle or the foot accelerator. Do not open and clo^e the throttle more than twice. 

The action which cansee the en- 
gine to "turn over" is prodnced 
by a gear of the electxlc motor 
sliding into mesh with toetk on 
the fly wheel; similar to the 
moshing of the gear teeth in 
the transmission. When push- 
ing down on the starting but- 
ton to throw these gears into 
mesh, if it should happen that 
they are in just such positions 
that the ends of the teeth of 
the startiner gear come against 
the ends of the teeth on the fly 
wheel instead of the teeth of 
one sliding between the teeth of 
the other, do not force them. 
Simply remove your foot from 
the starting button and again 
push down on the button. In 
thp meantime the gears will 
probably have changed their re- 
lative positions sufficiently to 
allow the teeth to me8h. Do 
not press the starting button 
while the engine is mnning. ■ 

Cadillac Model 63 control system. Note movement of gear shift 
lovor for speed changes. I 

VO. 04 — CMidSUac Ckmtxol ttystem and Wiring Diagram^Model 53, 55 Eight Oyllnder OiF. 
(Itg UstmetionB No. 19 and 28A for Delco ignition system.) 
(CUrt •• Milttod; error in nnmbtrlnff.) 


■MM dw»a ^***''».^ 


* '****^' * -*' 




ff ■ 

^ ^'^--.^ 

. 1 


- . .-.-1 r,» - ■> - 

T*******^'"^^^ ^^^ 




^^^\ " J 


«^— -JT" 






ic-.T .41* : 






The Twelve Cylinder V Type or "Twin Six" Engine. 

The twelve cylinder engine Is referred 
to in this instruction, as either a "twelve 
cylinder" or a "twin six." Manufacturers 
use both terms. Literally, a twelve cylin- 
der engine would mean a type of engine 
having twelve cylinders placed in line on 
a crank shaft having twelve throws. 

The "twin six" or twelve cylinder V en^ 
glne term, if we would be exact, consists of 
two sets of six cylinders placed at an angle 
of 60** over a regula*- six cylinder crank 
shaft with six "throws" of the crank. 

Therefore, if the reader thoroughly under- 
stands the six cylinder engine, then it will 
not be a difficult matter to understand the 
twelve cylinder V type. 





Note the evolution of 
raising cylindert from 

Before proceeding 
with the explanation 
of the "twin six," 
refer to the illustra- 
tion, and note the 
different angles in 
which cylinders are 

Construction: As 
previously stated, by 
placing six more cyl- 
inders on a six cylin- 
der crank case and 
placing them **V" 
type at an angle of 
60". The same crank 
shaft and practically 
the same crank case 
can be utilized with- 
out materially in- 
creasing the size or 
weight of engine. The 
extra addition being 
another set of cylin- 
ders and connecting 

On the eight cyl- 

180* to eO". Pig. 6 rep- s«j^, ttxrtt *^« ^„i 

resents the old style ?°?®' ^ *n>©, cyl- 

two cylinder opposed mders are set at an 

type of engine with cyl- 
inders 180' apart. Fir 
ing impalse S60*. 

angle of 90* or % the 
distance of firing of 

PU. 6 represeni. the the four cylinders In 
eight- cylinder engine Other words a four 
with cylinders placed fires every 180* 

pSlseYo"'- ''*''°* ^"' ^"^ fey «««f^g cyli-^- 
Pig. 7 represents the ?"« ,^^^ ^^ g^* ^"^ 
twelTe cylinder engine impulse every 90*. 
with cylinders placed . . ,. , 

60« apart. Pirinr im- A Six cylinder en- 
palse every 60^ of gine fires every 120", 
crank movement. therefore on a twelve 

cylinder we would place cylinders at an 
angle of Vi of 120** which would be 60* in- 
stead of 90" and therefore get a firing im- 
pulse at every 60* movement of the crank 

The "twin six" engine offers more even- 
ly divided impulses than the eight. Two 
cylinders are working together at all times 
and jiart of the time three are working 

Firing order: The crank shaft of a twin 
six is of the type shown on page 122. The 
crank may be* a right hand crank or a left 
hand, as explained. The firing order would 
be the same, that is, if you were to con- 
sider each block of cylinders on a twin six, 
as a separate six cylinder engine. 

For instance, refer to illustration fig. 8, 
page 135, refer to the block of cylinders to 
the left, when facing engine, we will desig- 
nate these as *rlght hand cylinders and will 
number them IR, 2R, 3B, 4B, 5B, 6B and 
all on the other side we will designate as 
left hand cylinders and will number them 
IL, 2L, 3L, 4L, 5L, 6L. 

The figures outside of the circles, indicate 
the order in which the cylinders fire on the 
Packard twin six. IB fires first then 6L, 
then 4B, 3L, 2B, 6L, 6B, IL, 3B, 4L, 5B, 2L. 

Laps of power strokes: If No. IB fires, 
and crank pin moves 60*, then 6L fires and 
moves 60" with IB, then 4B fires and moves 
14* with IB and 6L, at which time IB ex- 
haust valve opens. Therefore, making a 
period of 14 degrees, during which time 
3 cylinders are working together. 

Then 6L and 4B work together for a 
period of 46 degrees, after which time, 3L 
fires and works with 6L and 4B for a period 
of 14 degrees. 

So that with every 60* movement of 
crank shaft there Is a period of 14 degrees, 
during which time 3 cylinders work together, 
or in one complete revolution of crank, or 
360* movement, there will be 6 periods of 
14 degrees when 3 cylinders work together, 
and 6 periods of 46* alternating with these, 
when 2 cylinders work together. 

The cylinders on the Packard are stag- 
gered, see fig. 8, note left cylinders set 
ahead of the right. This is in order that 
the connecting rods can be placed "side by 
side" on the crank pin instead of being 
"yoked," see fig. 5, page 78 and fig. 10, 
page 129. 

The cam shaft: On the Packard, one cam 
shaft with a separate cam for each valve is 
used. On the National, 2 cam shafts are 

The ignition: see Packard supplement and 
page 135. 

*The right alda of an engine or automobile is the right side, when seated in the car, that is why 
we number the cylinders "right** and "left,** although it is the reverse when facing the front of 
engine. See *'8pecifleations of Leading Oars** and "Standard Adjustment of Leading Oars'* for 
esrm nglng twelve cylinder engines. 






60"D0WM ON 


WtiCM CWfcN*! MOtff^ feO^ s efnj3H on 
Piarw-fff-ttJ^J-S. WCPvfS 5C?* wt TMEfH HAVE 
n«?lHS-AiT ^WO* Dt^^TRiBLfTUR dOvt M E f+T*OR AT 
(D) lR.*34?At^PJt TOCO 7*nO»C 


^Twelve OyUnder 
Firing order: If we 
considered each mde aa & 
separate six eylinder en- 
glua, the firing order 
would be 1, 4f 2, €, 3, G. 

Nc»te tbe crank shaft; tbe 
throws 1 and 6, 2 and 5, 
3 and 4 are in line. Thii 
would ho a left hand crank 
shaft, see fig. 2^ F^g^ l^^* 

Supposing the firing order was 1, 4, 3, 6, 3^ 5, and eaeh bloc eoparato, the right hloe, ntart- 
in^ from front, would fire, IB^ 4B, 2E^ OH, 3B, SEL Now start at rear of left bloe, OL, 
81^ 51% 11% 4L, 2L. If the cylinders were numhered from the rcari an the left bloc, as 
1L% 2Liy 3L, etc.; the firing order would be IL, 4L, 2Lj 6L, 3L, 5L| same as the right hloa, 
bnt from rear to front. 

In order to see Just when three cylinders are working together, refer to fig. 12 and 13. 
Suppose cylinder IB fires; 2L will have fired just |irevIou9f therefore IK and 2L firing 
strokes will run together or "lap/' as it ia called, for & period of 46 degrees, for this period, 
note 2 cylinders are working together. Then cylinder 6L will start on its power atroke 
and will **lap" with 2L and IB for a period of 14 degrees (3 C)*linders working together 
during this 14 degree period of tmvet of crank pin), at which time 2L cuts out. 

The reUtfon of the movements of the dlstrlbntor and timer to the crank shaft: The 
timer and distributor revolve one-half the speed of the crank shaft, or the same speed as 
tbe earn shaft. The Packard "twin six'' employs two timers and distributors, operated 
at the same speed as the cam shaft. There ia a separate timer and distributor for each 
bloe of cylinders. See fig. 10 above, which is an exaggerated illustration in order to simplify 
the meaning. 

Now suppose the crank shaft moved 60* (see fig. 12 and 13). During that period of 
travel we would have had two cylinders on power for a period of A$^ and 3 cylinders on 
power for a period of 14*. 

The distributor on each bloc would, each^ have moved cam shaft speed (H that of 
crank), or % of 60* or 80 degrees. We must, however, have had 3 explosions, but 3 cylin- 
ders on power, during this period; 2Lr fired just before IR, therefore when piston IB 
reached top of its stroke and fired, we had then traveled 30 degrees (this meaas 30* timer 
sad distributor movement or 60* crank pin movement) on the power stroke of 2L. There^ 
fore 2L continues on its power stroke with IB, 30^; when 6L fires and the three continue to 
work together for a period of 7* more (timer movement, or 14* crank pin movement), (see 
fif. 13), when 2L exhaust valve opens and cuts out 2L, leaving 2 cylinders working to- 
gether for a period of 46* when the next cylinder fires, etc. 

Tig. 9: "Throws" of crank shaft are 120' apart, note crank pin "throws" 1 and 6, 
I and 4, 2 and 5 are in line. Crank revolving to the right, note cylinder IB is on top and 
would lire, then 6L, both being in Une, then 4B, then 3L, SB, 5t, 6E, IL, 3B, 4Lp 6B, 2U 

When No. 1 and 6 right connecting rods move €0% then 1 and 6L connecting rods will 
also mo^e 60*, at which point they will be on dead center, 

fig. 11. End seetional view of the Packard twin six; cylinder IB is 60* down on power, 
CL is oiB dead center — see page 136 for relative position of pistons. 

CKABT HO. 05— Twin Six Flrls^ Order. BelMon of the Speed of Orank Shalt \o 'DNiMtexsXAt. 

••Woe," MMd mhorm, /# term formerly used, should be block. See also paget 9\a, 9^0. 




I20«OM II 


60 •'ON X 



1 20* ON 






^!kM 1 ^- feo«oN 

All in ttOTTOM EMO 


't\\kO 60** DOWN 


Fig 6. 


Twelve Cylinder Piston 

Fig. 6 illustrates the reUUve 
position of pistons and what is 
taking, place In each cylinder wheo 
cylinder IB is Just starting its 
power stroke. 

Just consider each block of cyl- 
inders a separate six cylinder en- 
gine and it will be easy to under- 
stand the twin six. 

The crank pins are 120*" apart, 
whereas the firing impulses are 
60* apart. 

Note the order in which the cyl- 
inders fire is designated by the 
numbers outside of the cylinders, 
in heavy type. 

Note position of pistons when 
No. IB is just ready to go down 
on power. 

Engines with Overhead Valves and Cam Shaft. 
The cam shaft on this type is placed overhead and operated usually, by a vertical 
shaft driven from crank-shaft. See page 137. 

The aeroplane engine uses this principle extensively as will be noted by referring to 
pages 911 to 916. On page 916, note there are two inlet and two exhaust valves to 
each cylinder. 

The ** Sleeve Valve" Type of Engine. 

The sleeve valve engine differs from any 
other four cycle engine, only in its method 
of admitting and exhausting the gas. 

The sleeves: Instead of raising and low- 
ering poppet valves, to admit and expel 
the gas there are two sleeves with ports 
or slots in them; at certain times, these 
■lots on the same side of cylinder come 
in line as shown in figs. 2 and 5, chart 
69. These slcayes take the place of valves. 

The openings occur at the proper time, in 
a similar manner as any other valves are 
opened and closed — that is, the exhaust 
opens once during the four strokes and the 
inlet opens once during the four strokes of 
the piston. The sleeves of course sliding 
ap and down cause this opening and closing. 

Eccentric shaft: The sleeves are caused 
to slide up and down by an eccentric shaft 
(takes the place of a cam shaft), which has 
eccentrics raising and lowering small con- 
necting rods 06 & IS, see figs. 1 and 2. 
This eccentric shaft is driven by a chain 
from a sprocket on the crank shaft of en- 
gine. It is driven the same speed as any 
other cam shaft, ie., one-Half the speed of 
engine crank. The eccentric pin operating 
the inner sleeve is given a certain lead or 
advance over that operating the outer sleeve. 

This lead, together with the rotation of 
the eccentric shaft at half the crank shaft 
speed, produces the valve action illustrated 
in chart 69, which shows the relative posi- 
tion of the piston, sleeves and cylinder ports 
at various points in the rotation of the 
crank shaft. 

Valve timing: The timing shown is not 
different from that ordinarily used in pop- 
pet valve engines, but the valve area is 
greater than that of an ordinary poppet 
valve. The equivalent of increased valve 
area is gained, also, by the directness of 
the valve opening and the absence of re- 
strictions in the gas passages. 

Valve timing of the Steams-Knight four 
cylinder — see chart 69. Valve timing of 
the Stearns-Knight six cylinder; the same 
except inlet opens 4 degrees instead of 8 
degrees, and exhaust closes on top dead 
center instead of 4 degrees after. 

Setting ignition: Set cylinder No. 1 
piston on top of compression. Betard con- 
tact breaker box on Bosch magneto. Set 
points on interrupter just breaking. There 
is a mark on fly wheel which, when lined 
up with mark on cylinder, will show when 
1 and 6 or 1 and 4 are up. Fimg order 
on six is 1, 6, 3, 6, 2, 4 and 1, 3, 4, 2 on 
the four. 

The "Botary Valve" Engine. 

Is divided into two classes; the "single" chart 70 for description of the 
and the "doable." See figs. 6, 9 and 10, rotary valve. 


The "Botary Cylinder" Engine. 
In the ordinary motor car engine the cyl- the rotary "cylinder" engine the crank 
inders are bolted to a crank case and the shaft is stationary, and the cylinders re* 
erank shaft is made to turn around by the volve (used mostly for driving aeroplanes), 
force of the explosions in the cylinders. In See chart 70. 



CAM SH/irr 

'£ or TMtS 


Fig. 7: Note on the cam shaft there are twelve cazti 
operating the twelve valves. 

BOTTOM View OF cyc^i 

rsg. 2: OTtrheftd TalTM operated 
bf M enarlMad cam abaft; the Weid- 
\kj priAeipIe. 

TOf^ OF CVltHOeH Him 
€f\M SHAFT ^e/H^¥££^. 

YaiwmBZ In the tjpea of engine previously described the valves were either all on one side or oppa- 
sfta. or OTorhead. bnt operated by a plunger or tappet or by an overhead rocker arm. In this type the 
am ahMit la placad orazliaad aa per ng. 7, with the cams integral. There are two overhead valves for 
each eylmdar-— tee flgt. 8 and 4, therefore twelve cams, one for each valve. 


■kaft ia operated by a gear Gl on the crank shaft, which operates a gear 02. fig. 2. which is 
Uia lower timing gear; thia gear is placed at the lower end of a vertical shaft (S) with an upper 
gaar (03), which oparatea tha cam shaft gear (04). By referring to fig. 2, it will be seen how 
Hi O operatas the tappat arm (F), which in turn opens the valve against the tension of tha 
«rng (S>. 

Whila tha conatmetion variaa, the principle, it will be noticed, 
Tha daas ahaft tama one roTolntion to two of the crank shaft. 

is Just the same as any other engine. 

Tha cam ahaft moontad on the cylinder head, has four bearings and are 1 8/16 inch in diameter, 
n* and baaringa ara 1% by 1% in. long, and the middle ones, which are on either side of the driving 
gaar ara 1% by 1% inch long. A hole % inch diameter is drilled through the cam shaft for its entire 
faagth. and carriea oil to tha eama and bearings. 

Qfliflbdar haid in thia type engine the cylinder head is detachable from the cylinder, and the eyl- 
■dan ara all in ona block, therafora to grind the valves or to get to the valvea. the cover is removed, 
then tha ejlinder head. Fig. 4, ahowa the cylinder head removed and fig. 3, shows the cylinder head 
taracd up aida down, expoamg to view the valves seated in the cylinder head casting. 

To gzlnd walraa: First, remoTe head. If a single valve is to be ground the valve spring may be 
eviprasaad and pin holding spring removed, when valve can be dropped out and the beat ground, or the 
cam ahaft may be remoTcd, which ia easily done. Springs and pins removed and the cylinder head tamed 
ever oa a bench, as in flg. 8, and valves ground as any other valves. See index for method of valve 


„ Tha inlet opena 10* past top and fly wheel is marked "10." Exhaust closes at 
after top. Tharefora, aat tha cam shaft with piston No. 1, 10* past top center; cam just leaving ax- 
^ - which would ba a Uttie further iB 

To aat tha ▼aliraa: 
▼alra (a 

The gcara are then meshad at thia poL 
skaft saaa aa oa aa "L" tjp% ejUadar. 


direction of rotation, as it now has valve open). 
The timing of both inlet and exhaust is done by one cam 

yo. 06 — ^Tba OmlMld Valve Operated by an Oyerhead Cam Shaft — Weidlev six ejlinde: 
Lple. Note ejlinder head ia detachable with valves in the head. 

e7. haa baaa omittad and chart 70 follows this Charts G^ and C9 follow chart 70. 



The Rotary Valve Engine. 

Tbis type of engine Is tbe lame as any other 
fonr-cycle principle of gasoline engine, except in- 
stead of "poppet type^' of TalTOS the "rotary 
type" is used to admit ras to cylinder and to 
permit burnt gases to pass out. The Speedwell 
was one make of car which used the double-rotary- 

The single rotary valve can be compared with the 
poppet-valve type of engine using valves-in-the-head, 
operated by one overhead cam-shaft. Instead of 
poppet-valves and cam-shaft however, there is one 
long rotary valve, with openings as shown in figs. 
5, 6, 7 and 8. Note the position of these openings 
daring the period of intake, compression, firing and 

ONE or rni two rotary valve 

RODS Of VOuBti RCft"^ 

The rotary-valve is nothing more than a long 
cylindrical piece of metal with holes in the shape 
of slots cat in same as per S and D, fig. 8. In- 
stead of valves popping up and down, this rod is 
placed along side of cylinder and is operated by a 
chain or gear from crankshaft, and as it turns, the 
openings in the rods (rotary-valve) performs the 
same function as the poppet-valves. 

There are two types of rotary-valve engines, the 
doable valve and the single valve. 

The doable rotary- valve, can be compared with 
the poppet-type-valve engine using the T-head type 
of cylinder, which has the intake valves on one side 
and exhaust on the other. On the double rotary- 
valve we have an "intake rotary valve" on one 
side and the "exhaust rotary valve" on the other 
side, per figs. 1. 2, 8 and 4. On a four-cylinder 
engine, each valve would have four slots. 

Fig. 1 





Fig. 2 




Fig. 1 shows suction or indaction stroke just 
starting. As the piston starts down, the opening 
in intake valve (valve is rotating to the right), will 
be in line with opening in combustion chamber, 
therefore gas will be admitted. 

Fig. 2, Compression stroke; piston has reached 
and passed the bottom of intake stroke and is 
starting up on compression stroke, therefore, intake 
valve is just starting to close. Note exhaust valve 
is closed in figs. 1, 2 and 3. 

Fig. 3, Power or explosion stroke; opening in 
both valves are closed, piston will move down. 

Fig. 4, Exhanst stroke; piston is now starting 
ap on exhaust, therefore, opening in exhaust valve 
is open to cylinder, and burnt gases will pass out. 
Intalce valve is closed. 

The Botary Oylinder Engine. 

lUnstration flg. 2, shows the Gnome seven cylin- 
der engine, see also, page 010 for the Onome nine 
cylinder engine. 

In the rotary-cylinder en- 
gine the crank-shaft is held 
stationary and the cylinders 
are mounted on a cylindrical 
crank -case which can re- 
volve. Connecting rods are 
fastened to crankshaft-pins, 
fie. 1. 

When an explosion occurs 
In one of the cylinders the 
energy can do nothing else 
but force the piston down. 
This action turns the rod- 
holder on the crank-shaft, 
which causes the rods, pis- 
tons and hence the cylinder 
to revolve as a unit. The 
crankshaft, flg. 3, remains 
station a r y 
and due to 
this fact, the 
pistons will 
assume dif- 
ferent posi- 
tions in the 
cyl i n d e r s 
owing to the 
location o f 
the rods on 
the crank 
pin. For in- 
I stance. i n 
F t h e move- 
ment of the 
cylinder A 
from X t o 
Y, the pis- 
ton in the 
cylinder will 
travel down- 
ward, as 
shown in the 
illustration, until it reaches bottom of its stroke. 

CCBART KO. 70 — ^Rotary Valve Engine. Botary Oylinder Engine. 

(€Jhart 67 omitted; error in numbering.) See page 910 for Gnome rotary cylinder engine. 


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The mitin principle of this 
engine (made uoder Knight 'f 
patent) in thi^ substitution of 
eliding valvei for the usual 
poppet or tappet valves, The 
feUdinj; valvefl consist ol two 
concentric shells of 

cast iron accurately turned . 
workiof in between the 
driving platon and the cyl- 
inder walls, These shells 
have two series of large area 
ports or slots cut in the up- 
per ends, which re^ster to- 
gether at the required in* 
slant la the respective 
strokes of the piston. One 
pair of slota form the inlets 
and the other pair the ex* 

Tlie sliding shells of 
each cyUnder, tvhich 
have a relatively short 
Biroke, about 1 inch, 
are driven by two 
short connecting rods 
or tide arms working 
off a lay crankshaft, 
the cranks having a 
very small throw, 
which takes the place 
of the CAinshaft in the 
tappet valve form of 

This Yalve^operatlng 

shaft rotates at half 

the speed of main 

crankshaft. The £hd» 

ing &heli& extendi right 

up into the d<*i»p tone- 

shaped combustion h^ad, which is n di* 

tachable unit. This head ii of a 9^i'ei«1 

design in&omu^^h that it i* provid-d with 

a set of piston rings, three narrow and 

on*» double, the Utter being t-p^cialiy wide 

and t^'rro^?d the compre^^sTon ring. These 

rings prevent any escape of pressure in 

an upward direction, whilst the n^^^nal set 

of three rings on the working piston mnin* 

tuin pre*5ure tight ne&.s in the lonrr di- 


CSet next page for farther detail.) 

f-a A T>f»» JgTQ 

08 — The Knlgbt Sle«Ye Valve Type of Engine, used on 8teama-Knl£ht Oat. Ck\&^ 

fi •» f«ege 141.) 



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CHART NO. 69-4Stearns-Knight Sleeve Valve Engine. 



*CARBURETION: Principle, Construction, Operation, Carburetor 
Parts. Types of Carburetors. Throttle. Speed Control. 
Heating or Vaporizing. Gasoline Feed Systems. 

Carburetion Principle. 

Meaning of carburetion: The mixing together of gasoline vapor and air 
is called ** carburetion," and the device that keeps the two in proportion is 
called a ** carburetor/' 

To get energy out of the gasoline it is necessary for it to be converted 
into a vapor and then mixed with a volume of air before it can be exploded 
in the cylinder. 

There are two ways of producing this Vapor, one being to expose a con- 
siderable surface of this liquid to the air, which is also caused to bubble 
through it and thus become impregnated with the gasoline vapor. This was 
the original method and was called the ''surface" type of carburetion. 

The second method is to "spray" the liquid gasoline through a fine 
spray nozzle or jet into the mixing or vaporizing tube and into which air 
can be drawn to intermingle with the vapor. 

The device in which this operation is performed is termed a ''carburetor/' 
and the operation itself is known as "carburetion/' from the fact that the 
gasoline largely consists of carbon. The mixture might also be termed "car- 
bureted" air. 

Amount of gasoline and air: It has been found that the best explosive 
mixture with the gasoline commonly used, is a proportion of •M parts air to 
1 part gasoline, this when maximum power is desired and ranging to 17 to 1, 
the latter for maximum economy. (Proportioned by weight of air and 

Pure gasoline vapor will not burn; it must be mixed with air before it 
can be used in an engine. To burn with the greatest rapidity and heat, the 
air must be in correct proportion to the vapor. The exact amount of air to be 
mixed with a certain amount of vapor depends on the quality of the gasoline, 
and other conditions. The carburetor, by which the proportions of the mix- 
ture are maintained, is so made that a current of air passes through it when 
the pisten makes a suction stroke. See chart 71 — "air intake." 

The air goes through this passage, in which is a small pipe called a "spray 
nozzle" that sprays the gasoline, so that it comes in contact with the air (see 
spray nozzle, page 141). The gasoline being volatile, is taken up by the air, 
and the mixture goes to the cylinder. 

The amount of air that may flow through the carburetor, and the quan- 
tity of gasoline that may flow out of the small pipe, are adjustable, so that 
for a certain amount of gasoline the proper proportion of air may be admitted. 

When the mixture is not correct ; that is, when there is too much or too 
little air for the gasoline flowing out of the small pipe, the running of the en- 
gine is affected, and it will not deliver its full power. 

When there is too much air for the gasoline, the mixture is said to be too 
poor or lean; when there is too little air, the mixture is said to be too rich. 

The carburetor is connected to the inlet pipe, and no air or gas can enter 
the cylinder through the inlet valve without first passing through the car- 

*For Carburetor Trouble and Remedies, see index for **Dife8t of Troubles,** and next instruction. 
*TliMt is. 14 to 1 or rich mixture is best for quick acceleration, or 15 to 1 or leaner mixtore boat 
for pulling with wide open throttle, and 17 to 1, or still leaner mixture, for high ipoed woft 
(HgnreB onij spproximMte). 


The air drawn through the carburetor on the suction stroke enters it 
through the **air intake*' (see illustration, page 141), and passes around the 
spray nozzle, drawing gasoline with it ; the level of the gasoline in the float 
chamber then drops, and the float drops also and permits more gasoline to en- 
ter the float chamber. 

It is in the "mixing tube,** or ** mixing chamber," as it is sometimes 
called, that the air is brought into contact with the gasoline. The ''spray 
nozzle," projects into the mixing tube, so that it is in the center of the current 
of air. 

How the gasoline is drawn into cylinder with the air: When the air is 
not passing through the mixing tube, the liquid gasoline standd just below 
the open end of the spray nozzle, but as soon as the current of air passes 
through, it sucks the gasoline out. The current of air sucks up the gasoline, 
on the order of a child trying to draw the last few drops of soda through a 
straw, drawing in really more air than soda. 

The piston of the engine, on its suction stroke produces the suction effect 
similar to a squirt gun drawing in water. 

The inlet valve must be open to permit the gas to be drawn into the cyl- 
inder — ^which it is, if piston is on the suction or intake stroke, but no other 

"^The adjusting screw or "gasoline needle valve" regulates the amount of 
gasoline to be adi^ted into the mixing tube through the spray nozzle or jet. 
The regulation of this needle valve is very important, and after once being 
properly adjusted, a very slight turn one way or the other will affect the 
running of the engine. 

The throttle valve, usually placed in the mixing tube, above the spray 
noade, governs the amount of gas which enters the cylinder on the suction 

The throttle valve lever on carburetor, connects with the throttle lever on 
the steering wheel. Moving the throttle lever on the steering wheel, in a cer- 
tain direction opens the throttle valve on carburetor, which increases the speed 
of the engine. 

The more gas admitted by the throttle lever through the throttle valve, 
the more gas will enter the cylinder; hence more power or greater force on 
the power stroke, thereby giving more speed to piston of engine. 

Moving the lever in the opposite direction closes the throttle valve on 
carburetor, reducing the amount of gas which enters the cylinder, thereby re- 
ducing the speed of the engine. 

The float,. in the carburetor is provided merely to prevent the gasoline 
overflowing and running out of the spray nozzle, when engine is not running. 
The float is adjusted so the level of gasoline will not quite reach the top of 
the spray nozzle or jet. 

The floats are usually made of cork or hollow metal balls, which float 
in the gasoline inside of the mixing chamber. A needle point arrangement is 
connected with the float, which cuts off the gasoline flow when the engine 

The reason why engines must first be cranked, before starting, is due to 
the fact that a charge of gas must be drawn into the cylinder, then compressed. 
Compressed gas is ignited by the electric spark; this produces the power 
stroke, and the power from this combustion of compressed gas, together 
with the momentum of the fly wheel will keep the engine in motion until the 
next power stroke. The cycle operation of suction, compression, power and 
exhaust is repeated over and over again. (See page 58 for explanation of the 
four cycle principle.) 

*ThiB adjafting screw hat been discarded on some makes of carburetors. 



HMScum mi£r 



iioii _iy. 

I V 


Fi«. 1 — The principle of a simple float feed carbnretor. Note that the gasoline flows from 
tank through the "gasoline inlet pipe" to chamber of carburetor in which there is a float. 

The purpose of the float is to cnt the flow of gasoline off when the chamber is full, other- 
wise the gasoline would overflow at the "spray nozzle." 

When the float is properly set (usually determined by its weight, er adjustment of float 
needle valve), the gasoline will not overflow at the nezzle. 

When the engine Is running the suction of the piston draws the gasoline through the 
mixing chamber from the spray nozzle, through the intake pipe from carburetor, through the 
intake valve on engine. 

Ai the gasoline is consumed in the engine, the level of the gasoline in the float chamber 
drops and thereby causes the float to drop and more gasoline enters the chamber. 

There are different methods used on various makes of carburetors for operating the float 
and cutting off the gasoline, but the principle of practically all carburetors is about the same. 

In fig. 1 the main air supply Is drawn in at the bottom of the **mlzlng chamker" but 
inasmuch as the best power of an engine is obtained by getting exact proportions of air and 
gasoline, the reader will note that if the speed of the engine varies the air proportion will be 
too great or not enough, therefore an auxiliary air intake which is automatic in action, is pro- 
vided on most carburetors. 

M4&li*f£ iitiwr 


In fig. 2, note that an "auxiliary alT inlet" Is placed In the intake pipe above the 
gasoline outlet; this valve is automatic; if the engine is running at high speed the auxiliary 
air inlet will open in proportion to the speed of the engine, the suction being greater or less 
according to the speed of the engine. 

Another feature of carburetion is to break the gasoline up into as many flne particles as 
possible so that the air will more readily mix with the gasoline and form a vapor. There are 
different methods of doing this which will be shown further on. 

There are many different methods of arrangement of the float and air valves, but the 
fundamental principle remains the same. 

OHABT NO. 7»— A Simple Form of Carburetor. 

P!«. 1. — ^BCajbach conceived the idea of using a float to keep the gasoline in apray nossle at a con- 
stant level and to draw air around spray nossle. 
n<. 2.— Krebs. Uter, added the auxiliary air valve. 



Parts of a Carburetor. 

There are various types of carburetors, 
in fact a score or more; although the con- 
■imetion varies, the principal parts are for 
the same purpose. 

Classified according to structure and op- 
eration, we will mention the construction 
of the parts now in general use. 

Floats are usually made of light brass or 
copper in various hollow forms; the joints, 
if any, being carefully soldered or brazed 
so that gasoline cannot enter the float itself. 
Floats are also made of cork, well shellaced 
so that they will not absorb gasoline and 
lose their buoyaney. 

The sole duty of the float is to maintain 
a predetermined level of the gasoline in the 
carburetor. This level is generally a small 
fraction of an inch below the jet or nozzle 

As gasoline flows from the main supply 
tank through the gasoline pipe or line into 
the float chamber of the carburetor, the 
float rises and the needle valve shuts off 
the further entrance of the fluid into the 

When the engine is running and using 
gasoline the float in the carburetor is con- 
tinually falling and rising slightly, always 
maintaining the approximate gasoline level 
in the float chamber. 

There are many types of floats and float 
mechanisms as will be seen in the illustra- 
tions of various carburetors in this instruc- 
tion. By referring to chart 74 the reader 
will observe several float and float valve 

Gasoline leaking into the float would in- 
crease its weight, thereby changing the 
proper gasoline level in the spray nozzle 
and cause the carburetor to flood. 

Float valye mechanism; To the float an 
attachment is provided which will stop the 
flow of gasoline when engine stops. This 
action is obtained by the rising of the float 
(see ^g. 1, page 148), also study the sim- 
plified explanation on page 141. 

The valve which cuts off the flow of 
gasoline is called the float needle yalye. 

Side float type of carburetor: The float 
feed arrangement shown in chart 72, is 
shown placed to the side of the mixing 
tube. This form of carburetor is called a 
side float type. 

Another side float type is shown in flg. 3, 
chart 73: The float in this type of car- 

buretor is usually a tight box made of thin 
brass, the joints being made so there is 
little danger of leakage. In order to offset 
the danger of changing the level of the 
gasoline by tilting, the float and mixing 
chambers are as close together as possible. 

On the float arm is a small collar, in which 
rests the arm of a rocker, the rocker being 
pivoted in the center. The other arm of 
the rocker rests in a similar collar on the 
stem of the float valve. 

As the float rises, it carries with it its 
rocker arm, the rocker turning on its pivot. 
This depresses the other arm of the rocker, 
which closes the float valve and stops the 
flow of the gasoline into the float cham- 

This is a very usual arrangement of the 
float valve, as it permits the valve to move 
downward as the float is moving upward in 
floating on the gasoline* 

The rod through the float forms the 
primer, or "tickler," because depressing it 
lifts the float valve and admits gasoline 
for the purpose of priming, for starting 
in cold weather. 

In another form, the valve stem passes 
through the float, and is separate from it, 
the inlet of gasoline being at its lower 
end (fig. 1, chart 74), left illustration. 

A pivoted arm, or sometimes two or more 
are so set that the ends rest in a collar on 
the valve stem, and the outer ends, which 
are heavier, rest on the top of the float. 
As the float rises it lifts the arms resting 
on it, which depress the valve stem, closing 
the valve. When the float falls, the weighted 
end of the arms fall with it, lifting the valve 
stem, and thus opening the float valve. 

There are several other methods of 
connecting the float with the float valve, 
as shown in chart 74, page 148. 

The ' ' gasoline adjustment or needle yalve * ' 
on aboye carburetors are similar to the sim- 
ple form of carburetor described in chart 
72 — as is also the ** auxiliary air inlet," 
but they are placed at different positions, 
yet giving the same results. 

The concentric float type: The floats are 
not always placed to the side; they are 
quite often placed around the mixing tube 
as shown in figs. 1 and 2, chart 73. When 
the float is placed around the mixing tube 
it is called a concentric type of float. 

'Dyke's worklag model ezpUing a type of float mechanism need quite exteneively abroad. The 
throttle on this type of carburetor is called the "sliding or rotary throttle vaWe type,*' lee 
page 164. 
*Fer mdi^atmnt of floata of various standard carburetors, see next instruction. 



FUMt' ffm^ Siiffns 

C^^OLf/rr tifi^T' 

1,— Carburetor with thQ Flo«t 

Mt£&tC ¥MiM§ 


Aroimd tlio Mixing Chamber, called 
the cottcentric typ« of float. Air supply 
is drawn in at bottom of mUin^ cham- 
ber b«low the Bprg/ GOizle. This U- 
luatT&tion ihowa onlj the main air 

Flf, 2. — Carburetor with the FloSpt Ansuitd the 
Mixing Chnmber (also a concentric type). Air 
supply is at the bottom, below the mijclng cbatnter 
and is called the ^ ' main air supply, ' ' 

An Antotaatic AiucHlar? Air Supply is shown at 

the top of the carburetor. This auxiliary air valve 
is called automatic ^ because the air is automaticaUj 
controlled by the spring tension against the i^alve. 

If tho EnglnQ la Btumliig Fafit the valve will 
open wider and admit more air, eauaed by a greater 

The Throttle Val^e (Butterty Typt), is shown 
in the outlet tube. This outlet tube connecta with 
the intake pipe of the engine. The opening and 
closing of thia throttle admits more or lesa gas to 
the engiue and is controlled by hand lever on the 
steering wheel. 

^«»*»r %*%%n 


Fig. 3.— Thia Type of Carbmretor has a Side Float Chamber, Note the float valve me- 
fihanism attached to the float, to cut off the gaaoUne. The main air inlet is at the aide, but 
permits the air to enter below the apray not^le. 

The Automatic AuxlUary Air Supply Is taken in at the top (over the spray noide to the 

side of mixing chamber) » the same principle as the one in Fig. 2, but the arrangmont only is 

OHABT KO. 73 — Explaining the side Float Type of Carburetor and the Ooncantric Type of Float 
Arrangement. Also showing a different arrangement of the Auxiliary Air Intake Valve 
which can be placed to the side or overhead. ' 

Ooneentric means (baring the ^me center), the center of nozzle mixing chamber and of the ioat h«lBff Mentfeal- 



The carburetor with the float passing 
around the mixing tube is called a ''con- 
eentric float" type because the float sur- 
rounds both the spray nozzle and mixing 
chamber, all having the same center. This 
makes a compact carburetor and maintains 
a constant gasoline level in the spray 
nozzle regardless of the angle at which 
the car may be. 

The float valve mechanism closing the 
gasoline inlet is attached to the "float." 
On almost all concentric float carburetors 
the float is made of cork. 

The gaaollne needle valve controls the 
flow of the gasoline to the spray nozzle, and 
the correct adjustment of it is necessary 
for the operation of the carburetor. It is 
also called the ''gasoline adjusting screw." 
Don*t confuse this needle valve with the 
"float needle valve." 

In some carburetors this adjusting screw 
b placed at the top of the spray nozzle, on 
others at the bottom and on others, to the 
dde. When placed as shown in flg. 2, page 
148y it also helps to break thu gasoline 
into "spray." 

The regulation of this gasoline needle 
valve is very important and likewise very 
sensitive. After the carburetor is once ad- 
justed by regulating the auxiliary air valve 
and the opening of this gasoline needle ad- 
justment valve — the slightest turn one way 
or the other of this valve, will make a dif- 
ference in the running of the engine. 

The type of gasoline adjustment needle 
valve marked (e), flg. 2, chart 74, is of 
the hand operated type, being adjusted 
only occasionally. Other types of ''gaso- 
line adjustment needle valves" are; the 
mechanically operated needle valve, oper- 
ited by movement of throttle through a 
earn arrangement by hand (chart 84), and 
the automatic mechanically operated needle 
▼Uve operated by action of the auxiliary 
»ir valve (chart 82) called "metering 
ping," which will be treated farther on. 

The main air Inlet or supply is on all 
carburetors. See charts 73 and 74. Note, 
(ft), in fig. 2, chart 74, usually placed so 
the rush of air entering will surround the 
M or spray nozzle. 

The auxiliary air Inlet: The greatest 
^erence in the air type of carburetor is 
^ the position and action of the auxiliary 
ft^ Inlet. In the one shown (fig. 2, chart 
73), there are openings in the top ("extra 
ftir inlet"), closed by a valve pressed 
igainst them by a "coil spring," whereas 
^ fig. 2, chart 74 it is placed to the side. 

The auxiliary air valve is controlled au- 
tomatically by the vacuum created by en- 
|be piston which draws air through the 
ioxiliafy air intake, against a spring ten- 
>ba; for inatanea, see the auxiliary air in- 

take (d) in the carburetor shown in (fig. 2, 
chart 74). 

Another method for automatically open- 
ing and closing the auxiliary air intake is 
shown in fig. 1, chart 75, see the ball (N). 
Instead of a valve and a spring, balls are 
utilized instead. 

The air valve spring. The weaker the 
spring the less vacuum it will take to draw 
the valve open, and it may be adjusted by 
means of a threaded sleeve (as in fig. 2, 
chart 74), or in various other ways. 

The stronger the spring, the less air. 
hence ^'richer" mixture. The weaker the 
spring; more air, "leaner" mixture. 

Float chamber is that part in which the 
float operates; it is son>etimes placed around 
the spray nozzle and sometimes to the side, 
as previously explained. 

The float level: In different makes of 
carburetors, the level of the gasoline in float 
chamber, and the gasoline in the spray 
nozzle varies from about^ one-sixteenth to 
one-eighth of an inch below to top of the 
spray nozzle, see pages 166 to 168 "adjust- 
ing floats of carburetors." 

Spray nozzle: The fuel is discharged ' 
into the mixing chamber through the 
spray nozzle. (Also called "jet tube.") 

As its name implies, it is intended to de- 
liver the liquid in the form of a fine spray, 
which is: (1) vaporized more or less; (2) 
mixed with the entering air, and (3) car- 
ried by the suction into the engine cylin- 

The simplest form of spray nozzle is one 
having a single opening, as shown at (s) in 
fig. 2, chart 74. Some carburetors have two 
spray nozzles or jet tubes, as shown in fig. 
3. Another type has what is called a "mul- 
tiple jet" spray nozzle, as shown in fig. 4, 
see also upper right-hand illustration, page 

When a carburetor has more than one jet 
it is particularly adapted to a multiple of 
cylinders of large size and especially six 
cylinder engines. 

The mixing chamber consits of an enclos- 
ure or passageway containing the nozzle. 
The gasoline and air is mixed within this 
tube in proper proportions and then drawn 
through the throttle into the engine. 

The venturi tube around the spray noz- 
zle in the mixing chamber, is the accepted 
type and is now made in almost all makes 
of carburetors. The principle and purpose 
of the venturi tube around the spray noz- 
ple is in order to get a greater volume of 
air through a predetermined sized opening 
in quicker time. Explanation of the ven- 
turi action is shown in figs. 2 and 3, page 



Fig. 1 — The Different MechanlBms for operating the float valve on side float type of car- 
buretors — there are several other types in use. T — it the float, ususlly hollow metal. V — is 
the float needle valve. — is the opening leading to the spray nozzle. F — is the pipe from 
the gasoline tank. 

Fie. 2. — ^Type of carburetor with 
a concentric type of float. Note 
the float (t) (made of cork) is 
constructed so that it surrounds 
the mixing chamber and the spray 

The main air Intake (a) anx- 
lUary air Intake (d) single Jet 
spray nozsle (s) and throttle valve 
of the butterfly type, (h) are shown 
in this carburetor. 

The hand adjusted gasoline 
needle valve (e) is also shown. 

A hand controlled mechanically 
operated gasoline needle valve is 
shown in chart 84. 

An automatically controlled 
needle valve is shown in chart 82. 

Fig. 3. — A carburetor of the side float 
and * 'double jet" type. The hand ad- 
justed needle valves are shown at bot- 
tom of carburetor. 

Carburetors are also made with three 
or more jets, see flg. 6, page 149. 

Fig. 4— The Carter; a true MulUple Jet Type car- 
buretor with side float chamber. Seamless copper 
float. Auxiliary air valve spring subject to control 
from the car dash. This type is particularly adapted 
to six cylinder engines. 

This illustration is of the old model — see chart 
88 for improved model, upper left illustration 

caXABT NO. 74 — ^BxpUining Different Float MecbaxilBms. Gasoline Adjusting Keedle. 
I?oubl0 Jet and a Multiple Jet Carburetor. 




Despite tremendous advancement made in 

isteraal-combustion engines during recent 

jearsy original methods of carburetion are 

still — broadly speaking — in practice. 

The carburetor is still a comparatively 
primitive instrument, depending upon the 
saetion of the piston during its descent on 
the inlet stroke to draw from a jet (spray 
nozzle) or jets — variable or otherwise — the 
necessary gasoline to mix with the air. 

This jet can be a fixed size or it can be 
variable. This spray of gasoline is at the 
mercy of the temperature, valve timing, ex- 
haust, inlet and combustion head design. 

Carburetors as we know them at the pres- 
«it time, are divided into five classes: 

(1) Air valve type— In this the fuel issues 
through a fixed orifice and the addi- 
tional air required when the throttle is 
opened is admitted through an auxil- 
iary air valve. (See fig. 2, page 144 
and fig. 5, page 150). 

(2) Compensating ^et type — In this an aux- 


iliary fuel jet comes into action as the 

throttle is opened. (See page 181 — 

(3) Metering pin tsrpe — In this the size of 
the gasoline orifice (jet) is increased 
automatically to increase the flow of 
fuel as the throttle is opened. (See 
page 161 and 178.) 

(4) Expanding type — In this there are a 
number of fixed orifices which come 
in action one after the other as the 
throttle is opened. See Carter and 
Master, pages 179 and 180, also 151. 

(5) *The **plaln tube" or **pitot*' princl- 
plo: — Is a modern principle now being 
adopted extensively. The metering 
pins, dash pots, auxiliary air valves are 
dispensed with. The action is to supply 
an increased supply of gasolin-e or rich 
mixture for acceleration and then thin 
down to an economic mixture for nor- 
mal engine speed. See page 177 for the 
Stromberg using this principle, and page 
800 for the Schebler, as used on the Ford. 

Air Valve 
To properly understand the **air valve" 
principle we will begin with the first prin- 

For a simplified explanation we will use 
illustration fig. 1, page 144. 

The liquid gasoline enters the float cham- 
ber from the supply tank through the 
"float needle valve." 

In the "float chamber" there is a* 'float," 
made either of cork, well shellaced to keep 
out moisture, or in the form of an air-tight 
metal box, which floats on the gasoline. 

As the gasoline enters, the float rises, 
closing the gasoline needle valve, shutting 
off the gasoline when it has reached a cer- 
tain depth. 

The gasoline runs out of the float cham 
ber to the spray nozzle, the float keeping 
the gasoline at the same level in both. When 
the suction of piston draws the gasoline out 
of the spray nozzle, the level of the gaso- 
line in the float chamber drops, and as the 
float sinks, the valve is opened and more 
gasoline admitted. 

When the spray nozzle is made with a 
■mail opening, the gasoline comes out in tlie 
form of spray, instead of as a stream, which 
makes it vaporize quickly. 

In some carburetors, as the gasoline 
comes out of the spray nozzle it strikes 
against the end of a head projection, which 
breaks it into finer spray, and as the object 
is to make it vaporize as quickly as pos- 
sible, this is an improvement. 

In tbe simple float feed carburetor shown 
tn tg. 1^ page 144, and flg. 4, this page, it 


is only possible to adjust the amount of 
gak)line flowing to the spray nozzle. This 
is called the *'Maybach" principle (see fig. 
1, page 144). 

Therefore the sim- 
ple form Just de- 
scribed Is satisfac- 
tory enly for an en- 
gine which runs at 
a steady constant 
speed, for the speed 

of the air current 
through it does not 

change, and the gasoline may be adjusted 

to correspond. 
The engine of an automobile, however, 

does not run at a steady speed; sometimes 

it is running fast and sometimes slow. 

The speed of the air current passing 
through the carburetor depends on the speed 
of the engine; when the engine is running 
fast the speed of the air current through 
the carburetor is much greater than when 
the engine is running slow. 

The greater the speed of the air current, 
the more gasoline it will suck out of the 
spray nozzle, and the adjustment of the 
gasoline flow that will give a correct mix- 
ture at a low speed will give a rich mixture 
when the air current moves at a higher 
speed. For this reason the air supply must 
also be varied in order to give the proper 
combustible mixture. 

Auxiliary Air Valve. 
To vary the air supply, different methods 
are used, but one used most is the auxiliary 
air valve, and this is where the ''air-valve 
tjrpe" carburetor derives its name. 

*Tke "Pitot tube" la an instrument for measuriug pressure In moving streams of gas or liquids. Oan 
b« ttted facing Id any direction, but as applied to the carburetor faces down stream. 
Th^ PItot tube hag been used for years for measuring fire streams, chimney drafts, etc. In the car- 
b«r«tor it ii afimply used to provide air at sufficient pressure to force the fuel from the ^«i\\ ktl^ \v« 
CBcIoMd In the carburetor. 



The Auxiliary Air Valve — its purpose. 


1 II I.^ 





rvS% — ' 

aJl r""^\. 


f^ 1 ti 

' AIR. 

mix* /ar M»» tpt^t t** 

Maybacb conceived the idea of using a 
float to keep the gasoline in spray nozzle at 
a constant level and to draw air around the 
spray nozzle as per fig. 1, page 144. Kreba, 
then added the auxiliary air valve, as per fig. 
2, page 144. 

The auxiliary air valve was designed for 
engines which run at cbanging speeds, so that 
an extra supply of air was admitted when 
the air current flows so fast that it would 
result in too rich a mixture. 

The action of 
this auxiliary air 
valve depends on 
the greater or 
less suction, that 
faster or slower 
speeds of the en- 
gine gives. 

In this parti- 
cular type, fig. 2, page 144, and fig. 2, 
page 146, the extra supply of air, which re- 
duces the rich mixture formed in the mix- 
ing chamber, is admitted through the valve 
placed above the spray nozzle which is con- 
trolled by an adjustable spring. 

The suction produced from the suction 
stroke of the piston draws the auxiliary 
valve open, just as an automatic inlet valve 
is drawn open. 

As the rush of air through the mixing 
chamber becomes greater and greater, be- 
cause of the increased speed of the engine, 
the air valve is drawn open corresponding- 
ly wider, the spring being adjusted so that 
the proper amount of fresh air is admitted 
to bring the rich mixture to the proper pro- 

The float feed and the spray nozzle ar- 
rangement in both fig. 1 and fig. 2, page 
144, are the same, the difference being in 
the auxiliary air inlet in fig. 2. 

See fig. 2, chart 74 and note the auxiliary 
air valve as applied to th Schebler model 
D carburetor. 

The disadvantage of this type is that ow- 
ing to the relieving action of the spring 
valvo, it does not increase the proportion 
in ratio, and is hardly suitable for the 
present day high speed flexible engine. 

There are s»n-eral different models now 
manufaoturod, based on the principle of the 
auxiliary nir valve only. Tn these, the 
problem is worked out in different ways: 
one nmnut'aoturor nsos a ** spring-controlled 
valve**; nnothor hopes to jrot better results 

by regulating the movement of the valve by 
"two springs," instead of one; still another 
maker adds an "air dashpot*' with the 
hope of getting finer regulation and a bet- 
ter functioning of the auxiliary air valve; 
another uses a "dashpot filled with gaso- 
line*'; and there are others who use metal 
"balls** to serve as the auxiliary valve; 
while others use what are kfiown as 
"weighted air valves/' in which the suc- 
tion lifts balls (L), as in fig. 1, chart 76, 
thus admitting the air which sweeps over 
the spray nozzle. While they all differ 
in the details of working out the design 
they are, nevertheless, based on the baSc 
principle of the auxiliary air valvo as 
originally worked out, in fig. 2, chart 72. 
For simplicity in nomenclature we will re- 
fer to this type as the auxiliary air valve 

For air valve types of carburetors, see 
Kingston, fig. 1, page 152; Schebler model 
D, page 148. 

Relation of Acceleration to Gasoline 

The rapid advance of high speed and 
multiple cylinder engines, have demanded 
"quicker acceleratixm," meaning quicker 
"get away" or "pick up" of the engine. 

Flexibility of control means practically 
the same thing or the capabilities of the 
engine to "pick up" from low to high speed 
and vice- versa. Bapid "acceleration" and 
"flexibility," both call for a sudden 
greater amount or percentage of gasoline 
to air. Quick acceleration therefore de- 
mands a surplus of gasoline for but a brief 
period after which the normal supply will 
care for the engine. It may be but a mat- 
ter of a few seconds, yet it is of importance 
that this additional supply be ready and in 
available form for that brief period. 

The Dash Pot. 
To meet the sudden denumd for gasoline, 
the added nozzle, or multiple jet has been 
introduced by some makers, so that when 
the suddenly-opened throttle brings the 
auxiliary air valve into use, the valve in 
turn brings more gasoline into the mixture, 
an added supply. One maker does this by 
a "dashpot" on the auxiliary valve stem, 
this dash pot performing a regular pump 
stroke and forcing gasoline into the mixing 
chamber by way of a separate nozzle as the 
auxiliary air valve opens. Once open the 
pumping action ceases, but the nozzle re- 
mains open for a more even demand for 
more fuel. 

The Compensating Jet Principle. 

Types of carburetors coming under this 

.^<« stated, under a heading ^2) on page 
149; the compensating jet type of carbure- 
tor JH where an auxiliary fuel jet comes into Stromberg model 
met ion, ua iho throttle is opened. page 179. 

heading would be the Zenith, page 181; 
H/» page 177; Marvel, 



The Metering Pin Principle. 

Metering pin type — In this, the size of the 
gasoline orifice or jet, is increased auto- 
matieally to increase the flow of fuel as 
the throttle is opened. 
For instance, note the 
connection between 
the "throttle" and 
the "needle valye" 
in the spraying nozzle 
as shown on page 
174. By a carefully 
computed cam action 
it is possible to give a 
sudden lift of the 
needle and thus get the 
desired fuel supply 

n«. 1. The 
Bfta«t1er id o d e I 
* 'T* • with meter- 
ing nin operated 

by ^e ModlUry 
enr Tilre. 

The same company in another model-(T), 
have connected the "auxiliary air valve** 
with the "needle valve" in the nozzle (see 
above, and page 172), so that as the air 
valve opens there is a larger nozzle open- 
ing for the flow of gasoline. This principle 
ia called the "metering pin" method. 

Proportion of air and gas: All of these 
methods of providing "acceleration" are 
based on the accepted belief that in car- 
bnretion, different mixtures of air and gaso- 
line vapor are needed for different engine 
raqulrementB. The days are past when the 
vniform-mlxture argument dominated, the 
argument that the ideal carburetor was one 
that would give, say, a mixture of fifteen 
proportiens of air to one of gasoline vapor 
for all speeds, "acceleration," "hard 
polling" with open throttle, and high-speed 
work with open throttle, etc., etc. The new 
mle is that the amount of gasoline fed into 
the air volume must be changed according 
to demands, and that if a twclve-to-one or 
"rich" mixture might be best for quick 
acceleration, that a fifteen to one, or 
"leaner" mixture may be best for pulling 
with the throttle wide open and a seventeen 
to-one, or still "leaner" mixture for partic- 
ularly high speed work. Therefore a "vary- 
ing mixture" must be supplied. 

Example of a Carburetor with Both 
a Metering Pin and Dash Pot. 

The Bayfield uses a "metering pin," 
""hieh pin is lifted as the throttle opens in 
the main jet N, fig. 2, through a link ar- 

rangement, and so establishes a right to 
be classifiod as a metering pin type, but it 
goes further. It incorporates an auxiliary 
nozzle (AN) which also has a metering pin 
which is depressed when the auxiliary air 
valve opens. Thus by having two distinct 
nozzles it establishes its right also to be 
classified as an expanding type of instru- 

1*1 rt 

Fig. 2. The Beyfleld carburetor prinoiple 
with "metering pin" connected with the 
throttle and "daui pot/' with anzillary air 
Intake, (see also page 175.) 

But the Bayfield goes still further in that 
it combines a pumpUig action on the gasoline 
in the auxiliary nozzle AN whereby a very 
rich mixture is furnished for acceleration 
whenever the air valve is suddenly opened. 
This is accomplished by the piston on the 
lower end of the air valve stem, this piston 
working in a "daifhpot" filled with gaso- 
line. Gasoline enters the dashpot above the 
piston and is admitted-to the space below 
the piston by the disk valve in the piston. 
When the air valve suddenly opens, forcing 
the piston downward, this disk valve is 
automatically dosed, forcing or pumping 
the gasoline upward through the dotted fuel 
passage into the nozzle AN, where it is 
sprayed into the inrushing air. Only when 
the valve opens is this pumping function 
occurring and at . other times the gasoline 
issues through this auxiliary nozzle accord- 
ing to the suction of the engine. Thus the 
Bayfield is a compound of two metering pini 
in conjunction with the pumping function 
for acceleratioi). 

Other makes of carburetors using meter- 
ing pins are the "Schebler" and "Stewart" 
see pages 172, 173, 174 and 178. 

Expanding Principle. Plain Tube Principle. 

In the expanding principle, there are a 
number of fixed orifices which come into 
-^ action, one after the 
other, as the throttle 
is opened. Types of 
this class of carbure- 
tors are shown in fig. 
6 and in the descrip- 
tion of the "Master" 
carburetor on page 

180, also on the "Carter" as described on 
page 179. 

Plain Tube Principle 

is different from this principle and other 
principles. It is the principle now being 
adopted by many carburetor manufacturers. 
For explanation of the "plain-tube" and 
"pitot" principle, see pages 149, 177 aijd 



^ » ^_ \ 

A..--:._try AIT I^t&kti £x?U2 

Carburetor Throttle Valves. 


There are three typee of throttle Talves; 
the butterfly, rotary and sliding (see chart 

The butterfly throttle valve is the type of 
throttle used on almost all makes of car- 
buretors. This type of throttle is shown in 
fig. 1, chart 76. The mechanism and method 
for controlling the throttle is shown in fig. 
4, chart 76, also see chart 91. (T). 

The throttle is placed in the mixture out- 
let, and the form that is shown is called a 
"butterfly valve." It is a disc of metal 
turning on pivots, so that it acts like the 
damper of a stove pipe. When wide open, 
the butterfly valve is edgeways to the flow 
of the mixture, but even in this position it 
presents resistance to the flow, which is 
eomething that should be avoided. 

The ••rotary" throttle valve, fig. 2, chart 
76, presents no resistance whatever for 
there is no resistance offered. Also see 
"Master" carburetor, chart 89. 

The sliding throttle valve is another type 
which presents no resistance to the flow of 
gaa. This type is seldom used although it 
was formerly used quite extensively when 
governors were used. (See chart 76, fig. 3.) 

Engine Speed; How Controlled. 
The simplest and probably the acknowl- 
edged popular method for controlling the 
•peed of an automobile engine is by opening 
■ad closing the throttle valve on the car- 
buretor by hand. 

A rod leading from the throttle lever 
on the throttle valve connects with a hand 
lever on the steering wheel. (See fig. 4, 
chart 75.) The driver then has the speed of 
engine under his control at all times. 

If running on a level and more speed is de- 
sired, the throttle is opened by the throttle 
lever until the required speed is maintained. 
By closing the throttle, the speed is de- 


The throttle valve is never entirely closed; 
the lock screw (X) shown in (chart 82) pre- 
vents the throttle from closing entirely. 
Therefore engine will run slow or "idle," 
as it is called, when the throttle valve lever 
on the steering wheel is closed and car 
standing. To stop engine entirely; throw 
oflP the igrnition switch, (see page 171). 
The Accelerator. 

This is the usual means for controlling the 
speed of the engine, see chart 76, fig. 4. 


In the early days the governor was used on a 
few makes of pleasure cars but discarded. The 
governor is now used extensively on track and 
tractor engines as a matter of economy. See in- 
dex "Governors," and page 154. 

There are two types; the "throttling" type 
which governn the amount of gas entering cyl- 
inders and the "hit and miss" type which gov- 
erns the spark by cutting it off when engine 
speeds up. 

The former is the type in general use and the 
latter is used to a great extent on small stationary 
gas type engrines. The larger stationary type 
engines use the "throttling^* principle, flg. 5. 
page 154. (see index "Governors.") 

When an engine is started by crstaking 
by hand, which is best done by a quick turn 
of the crank, it is necessary that a charge 
of vaporized, combustible gas be drawn 
into the cylinder, which is easy to ignite. 
It is also necessary to have a good electric 
ipark to ignite the gas. 
- If we attempt to start, depending only 
on a magneto to supply this spark, it would 
be necessary to "spin" the crank in order 
to get the armature of the magneto up to 
•nificient speed to generate electricity; 
therefore the magneto is seldom used to 
start on. The usual method is to start from 
coil ignition — its source of electrical sup- 
ply is derived from a battery — and after the 
crank shaft of the engine is in motion, then 
the switch is turned to the magneto, if a 
magneto is provided. If a generator and 
battery, then this action is automatic. Ex- 
plained further on. 

The modem method of starting an engine 
la by an electric motor, which will be ex- 
plained further on. 

In order to facilitate easy starting, by 
hand or motor, it is advisable to open throt- 
tle Just before stopping engine; in order to 
draw In a good charge of gaa — by speeding 
engine np with clutch out; this leaves a 
charge in the cylinder for starting later. 

Priming to Assist Starting. 
•When using the low grade gasoline, espe- 
cially in cold weather, the gasoline does 
■ot vaporize freely. Gasoline vaporizes 

^Remarks lOn Starting an Engine. 

more readily when warm than when cold. 
The most effective temperature seems to be 
about 170 degrees Fahr. 

Vaporizing really means evaporating, or trans- 
forming into vapor. The purpose of heating the 
mixture before it passes into the cylinder, is to 
make the gasoline more "volatile" or to evapor- 
ate quicker. 

When first starting, however, heat is not pro- 
vided, therefore some method of priming mnst be 
resorted to. That ix. draw gasoline into the cyl- 
inder, (see page 156). 

One method of priming is to prime with a 
"tickler," which means to depress the float by 
hand so that the float needle valve will open and 
admit gasoline to the float chamber. A wire is 
nsually run from this "tickler" to the front of 
the car. where the operator can pull it and flush 
the carburetor before cranking (fig. 6, page 156). 

Another method for priming is called 
the ** damper" or ** choke" method, and is 

shown in chart 78A. Instead of lowering the 
float, the air intake is closed. This causes 
an increased suction of gasoline and is 
called "choking" the air supply. 

**Too much priming, however, will fill the 
float chamber so full, that gasoline will run 
out of the spray nozzle, giving a rich mix- 
ture, on which the engine will not start, 
therefore it will be necessary to close switch 
and throttle, and crank engine a few times 
to draw in more air, then open switch and 
crank again, at which time engine ought to 
start if there is a good spark. 

After engine is started, then some means 
for heating the gasoline so it will vaporize 
more readily should be employed. 

•When an engine wiU not start during cold weather — nn effective method \« to pouT \)q\\\tx% 
water OT«r carburetor and inlet pipe. The "choker" or "damper" principle however, uftuaW^ %\w\.% 
SMia*. per page 169. ♦*See page 489. foot note, "starling an engine by openVne awvlcVv.** 
••Top mnch doeg one of three things— see page 205. explaining. JSoe also pagea 169, \1\, ^^"i, ^^^- 


rilHilTTI y VALVE 

Nu TlimnTl.K 



11, .'L 

^ ' 
















Til* 0»nUlf»i*l t««rnoi 

Carbnretor Throttle Valves. 
Tliere art three types of carbnretor throttle 
TalTes: (1) the butterfly type as per fig. 1;'(2) 
the rotary type per fig. 2. and (3rd) ilidinf throttle 
per fig. 3. 

The butterfly type is in general use; it may be 
placed in position as shown in flg. 1, or as per 
fig. 1, chart 75. Usually consists of a thin disk 
with a throttle lever which is connected with the 
hand throttle lever on steering wheeL 

The rotary type is different, but used for the 

same purpose. In the rotary type, the passage of 

gas from jet to intake manifold through passage 

(P), is controlled by a rotary cylinder (B). It is 

now shgwn full open, but by moving throttle lever (L), it can be 

closed or partially opened as desired. This is the principle used 

on the Master carburetor. 

The sliding throttle valve consists of a cylinder type throttle. 
but instead of being rotated, it is moved in or out of its passage, 
which controls the amount of gas passing to the intake manifold. 
Ah it is moved out, additional air is admitted through port holes. 
This type was the type formerly used with a governor. It is now 
practically obsolete. 

The Accelerator. 
Fig. 4. The accelerator consists of a foot pedal which opens 
and closes the carburetor throttle valve independent of the hand 
throttle lever. By referring to the illustration, it will be noted 
that the accelerator will operate the throttle of carburetor with- 
out moving the hand throttle lever by an arrangement as shown. 
When foot accelerator pedal is depressed, the rod (F) movea 
against a shoulder which is fastened to the throttle shaft. The 
end of the shaft (T) works free in a turn buckle (P). There- 
fore, the throttle can be opened without disturbing the hand 
lever. Or the hand lever can be operated without moving the 
foot pedal. The accelerator is used more than the haad 
throttle lever. Its purpose is the same as the hand throttle 
lever on the steering wheel; to open and close the throttle 
valve, (see also page 497, 492.) 

The accelerator pedal Is the usual means of controQiiig 
^the speed of the car. When pressed downward for increase 
-or released for decrease of speed, its action is instantane- 
ous. When the accelerator is released, the engine immedi- 
ately resumes the speed determined by the positions of the 
hand lever on the steering wheel. Although either the 
hand throttle lever or the accelerator may be used to con- 
trol the speed of the car, the use of the hand lever is ad- 
vised for beginhers. After confidence in driving has been 
gained, the more delicate action of the accelerator will be 

The word "accelerate** means to hasten, therefore the term 
is applicable here because it is quicker to operate throttling. 

The Governor. 
Fig. 6. * There are no pleasure cars nsing the goremor. Nearly all 
truck, tractor, marine and stationary engines nse governors. One 
type of governor which is a "throttling** tyne, is the centrifugal ball 
type as illustrated in fig. 5, and which, no doubt the principle is familiar 
to all. The "sliding" throttle in carburetor is actuated by the movement 
of the sleeve controlled by the balls (B). . The balls fiy out as the speed 
increases causing the throttle to close. 

Fig. 6. The gOTomor formerly need on the Packard: A "hydranlle** 
governor of the diaphragm type is located directly above the water pump. 
It is operated by the pressure of the water in the water circulation system 
and consists of a circular chamber divided by a flexible diaphragm of 
leather and rubber. On one side of the diaphragm is a water spaee 
through which peases the water of the circulating system. On the other 
side is an air apace and a plunger head against which the diaphragm presses. 
The plunger is directly connected with the throttle valve. 

If a decrease in the load on the engine causes its speed to Inereaae. 
the pressure of the water, circulated by the pump, increases and. eoa- 
sequently, the diaphragm exerts more pressure toward the rear, tend 
ing to move the plunger and thereby close the throttle. As the engin< 
speed decreases, the water preasure againet the diaphragm is lesaeno' 
and the throttle may open. 

The purpose of the goveimor is to prevent the engine from raeii 
when the load was removed, as by throwing out the clutch or stoppb 
the car Avitliout shutting down the engine, also to prevent driver ir( 
oh tain ing v^wr a set na iim n iB speed. 

Tins, hor^vor. was found unnecessary on pleasure automobiles. 
!.i):h speed is a desirable feature at will of the driver, which ie m 
fsaily accomplished with the movement of the hand throttle lever. 

The governor, howerer, la a Ttry deairabla feature on truck, tra 
aiui marine enginea where the engine ia supposed to run at one 1 
>:iC.i ^ci iV.f lo.ixl varied, as the governor would then keep the speed 
*:a: t .lit .o.;i:!i ti-.c load did vary and is a saving in fneL wear and 

isrvo* of ThrotUe Valves. The Accelerator. Govemon. The sliding thrott 
-** *V.»M\v. :k^ explain tho principle. 



^Vaporizing of QasoUne. 

Ab preyiouBly stated gasoline gives off 
aore vapor at about 170 degrees Fahr. It 
la tlie vapor mixed with air which Is most 
desired. With the proper mixture there is 
more uniform power and flexibility. 

**Heatlng Methods. 
There are several methods employed for 
vi^orlslng, as follows: (1) by passing hot 
water from the water circulation system 
around the water jacket of carburetor, or 
intake manifold; (2) by passing exhaust 
gases from exhaust pipe around the water 
jaeket of carburetor instead of hot water, 
tiao around intake manifold; (3) by taking 
the warm air from around the exhaust pipe 
and passing it through the main air intake 
of carburetor; (4) by heating the mixture 
as it passes into cylinder. 

The above methods can be classified under 
two headings: (1) heating the air as it pas- 
ses into carburetor; (2) heating the mixture 
as it passes into cylinder. See pages 159, 
157, 160, 187, 855. 

tHeat Begulatlon Methods. 
Carhnrettlng means to break up the gaso- 
Uiie Into Inflnlteslmally small particles, 
aechanlcally, without heating, which is 
caOad "spraying." This is the best method, 
but very difficult to do so, owing to the 
different amounts of gasoline passing from 
■pray nozzle, and on account of the varia- 
tion of the throttle or the speed. 

tif a low gravity of gasoline is used, It 
Is nacesary ta heat and vaporize the mlz- 
tnre, because it is practically impossible to 
break it up; but if it is a high gravity gaso- 
line, it generates into gas quicker. In other 
words, it is the vapor that w<e must obtain, 
which is possible with high gravity gasoline. 
Bnt in n^ng hlfl^ gravity gasoline remember 
It will not stand as much heating as low 
Cravity, for if there is too much heat used, 
then it makes the mixture so rare that the 
actual amount of gasoline that goes into the 
cylinder is so small and at such a low fiash 
point, it ignites quicker, and will burn and 
expand more like powder. It will do its 
work and cool before the piston j^ets well 
QBder way, furthermore the pressure on pis- 
ton does not last as long, (see page 161.) 

Owing to the low gravity gasoline now 
being used, the mixture Is not a true vapor. 
Instead of forming a gaseous mixture, it con- 
denses, inside of combustion chamber and 
manifold — therefore a plentiful supply of 
heat is required, (see pages 157, 158, 159.) 

Air control: Therefore, If some method of 
heating the mixture Is employed, as shown 
in chart 7 8 A, then the heat must be regu- 
lated, which is usually done by a dash board 
or steering column air control (fig. 4, chart 
78A), connected with the air intake of car- 

Temperature regulator: After engine is 
well warmed up it ought to have more air, 
and the more air used, less gasoline required. 

If warm air was drawn into the carbure* 
tor after engine was very hot, then the n^x- 
ture would be made too rare or lean. 

We also know that gas expands in direct 
proportion to the degree to which it is 
heated. Therefore, when heated too much, 
the gas is unduly heated or prematurely ex- 
panded to such an extent that it loses a cer- 
tain per cent of its energy. 

The best degree for general running ap- 
pears to be somewhat below the boiling 
point of water, i. e., between 170 degrees 
and 200 degrees Fahr. 

Therefore some means of admitting cool 
air must be employed which will mix with 
the warm air. This would be termed a 
''temperature regulator,'* and is very sim- 
ple. See page 169. 

The use of low gravity gasoline requires 
more heating or vaporizing than a high 
grade. It might be compared with the fir- 
ing of a furnace with soft coal. 

If soft coal l8 properly fired and la properly 
mixed with air, it will produce the most heat with- 
out producing very much smoke. Just so with a 
low grade of easoline. If properly vaporised it 
will work fairly well, otherwise carbon deposit 
and smoke will be the result, (see page 205.) 

High gravity gasoline may be compared with 
hard coal. It is very easy to get the proper mix- 
ture of air with the high gravity gasoline, be- 
cause it is so very "volatile" — meaning: there 
is more vapor, and less vaporizing is necessary 
and will "carburet" more readily; therefore it 
will work satisfactory in most any carburetor 
construction. Just so with hard coal, it will bum 
with less smoke and produce an equal amount of 
heat even though you burn it in an open shovel, 
and makes very much less smoke and carbon. 

On stationary and high duty marine engines 
as low a gravity of fuel is used, as kerosene and 
oil. but before it can be used it must be "vapor- 


A correctly heated carburetor runs on less 
gasoline than an unheated one, therefore a 
closer adjustment of the gasoline needle 
valve or a smaller jet is necessary. 

An engine requires more gasoline in win- 
ter than in the summer as the gasoline does 
not vaporize and readily mix with the air 
until warm. 

If intake manifold is heated with water, the 
temperature is not so liable to cause overheating, 
as the temperature seldom goes above 170 to 200 
degrees, especially if a thermostatic principle is 
used as per fig. 2, pages 180 and 187. 

When intake manifold is heated by ezhanst, the 
temperature is liable to increase to a high degree, 
when engine is run continuously for a long period. 
The latter system however, will heat the mixture 
quicker than the water system, when engine is 
cold. Therefore means for admitting cool air per 
figs. 1 and 3, page 159, and some means for cut- 
ting off the exhaust gases to manifold jacket ought 
to be provided, for long runs. 

*lfore h^iit l« reoiiired in rold weather than warm 

^'heating the mixture." 
18ce also pages 157, 159. 187 and 8G0. 

S8<« page 161. 

weather. **See oaee 855. Packard method for 



r — 


tfATCHBT wM^ne 

Fig. 1. — When Engine is first Started by hand 
or by a self-starter, the initial charge of gas must 
be drawn into cylinder. After it is compressed 
and exploded or ignited, the engine will then con- 
tinue to run. Note the starting crank releases after 
engine is started. 


Pig. 6.— The • 'Tickler* • Priin- 
ing Method^ p ishing the float 
down admitting more gasoline. 


On » Gold Morning after Engine and all parta have 
Bacome Chilled, we find that with the ordinary grade of 
gasoline now in use, the gasoline doef not vaporise readily 
until it is heated; therefore, consideraole cranking of the 
motor is sometimes necessary in order to ignite the cold, 
damp, unvaporised gasoline. 

There are Sereral Methoda of Overcoming this; one 
being to use a higher grade of gasoline, but even with the 
higher grade, which is difficult to obtain, on a real cold 
day the starting will be somewhat diflicult, with aome makes 
of carburetors. 

A plan quite often nsed is to have a small machine oil 
can filled with gasoline, which is squirted into the cylin- 
ders throuch the pet cocks, which are usually placed in 
the head of the cylinder. By injecting a small quantity of 
gasoline into each cylinder, then closing the pet cocks, this 
will give the engine its initial charge, and will often 
start the engine without further trouble. (See Fig. 2.) 

Another Method ia to open the Gasoline Adjustment 
Needle Valve Several Tnms before Oranxing; this method 
is not advisable, however, because this adjustment valve 
is a very sensitive adjusted part of carouretor, and will 
throw the proper working of carburetor out of order after 
engine is heated up. If this method is employed be sure 
and mark a notch on the head of the valve, so that it can 
be turned back to its original adjusted position (Fig. 3^. 

Becent Improvements in carburetors to make a motor 
"easy starting" consist of a mechanism which connects 
with the main air inlet and the auxiliary air inlet of the 
carburetor, which ptoses these openings while cranking. 
This method causes the suction of the piston to draw into 
the cylinders a quantity of gasoline, which gives the same 
effect as if squirted in with the oil can. (See Fig. 4.) 

The Usual and Oommon Method is to connect a wire or 
rod to a daoiper placed in the main air intake. When 
starting is difficult close the damper. (See Ohart 79.) 

In Either Method Explained. Bemember that a Good Hot 
Spark must be provided in order to ignite this raw gaso- 
line, because it is harder to ignite when cold than after 
it ia warmed up. 

It is also Advisable to be sure that no other trouble ia 
the cause of the engine not starting, for instance a leak 
around the intake pipe, leaky float or some obstruction in 
the pipe. 


Fig. 2. — ^Priming by pouring gasoline 
in top of cylinder, througV pet cocks. 

Fig. 3. — ^Priming carburetor, 
adjusting screw. 


Fig. 4. — ^A Damper is Proviaed in the main air 
intake pipe. When closed the suction of gaso- 
line is more than air Sometimes the tension 
of the spring on the auxiliary air valve ia regu- 
lated from the dash or steering post. Thia 
regulates the feed of gasoUne or air. 

OIL C*W V ^ 

Fig. 6. — The oil can 
primer where gasoline ia 
injected into manifold — 
simple and effective 
when other methoda falL 

Fig. 7.— i 

made primar; a 

%** glaaa bady 

oil cup of gaa en- 
gine type ia maad. 

•Fig. 10.— Til a 
spraj prtmar; a 
small injector 
pump. T^ ane- 
tion pari of pnmp 
is connected to 
the gaaoline anp- 
ply pipe between 
the tank and car- 
buretor. T h • 
other part eon- 
t^c^v^u-twroriJ nects to featake 

manifold; one stroke of phinger apraya a eharge 
into the manifold. Imperial Braas Co.. Ohieago, 
manufacture a pump primer of this typo, also 
Bay State Pump Co., 102 Purchase St., Boston. 

OSABT NO. 77— Different Priming Methods. (Also see Chart 78 for Eleetrie Primer.) 
■•• yage 169, for "choker" method, which is the approved method for priming. *A priming wzinklo which eaa 
bo naed in connection here, is to have an auxiliary tank on dash under hood — abont 1 pint or quart aiao and C 
with high gravity gasoline and use for priminfr mixture. -See also, page 579, 788 for OWrkOiltlllC 



Pig. 1. — Hot water heating of carburetor: The 
■anal method of connecting the hot water to the 
carburetor water jacket is to connect the upper 
vat^r connection to cylinder water jacket or pipe, 
and lower one to suction end of pump (between radi- 
ator and pump). See that the connections are made 
in such a way that water will drain out of the car- 
buretor jacket when system is drained. Place a 
shut off cock in the line for use in extremely hot 

Fig. 2. — Exhaust 
gaaes heating of car- 
buretor: The exhaust 
gases from the ex- 
haust pipe can be 
carried to the car- 
buretor water jacket, 
by tapping the ex- 
haust pipe and con- 
necting a flexible or 
copper tube to water jacket. It is advisable to 
ua aa larce a pipe aa possible — say H inch, as it 
kaa a tendency to clog up. The other opening of 
water jacket is left open by a copper pipe connec- 
tion extending to lower part of engine for emission 
of gasea. 

ng. 5 — Bnlck'B •shaoat heating of mixture. Not<.> 
the exhaust manifold which adjoins the inlet mani- 
fold (IM). The lower 
part of exhaust manifold 
(hot air chamber) is di- 
vided from the exhaust 
(above). Air passes 
through lower chamber 
which is heated. Hot 
air is also drawn into 
jacket around upper part 
of carburetor bv flexible 
tabe connection (FT). Also see page 179. Marvel 
csrbnretor which is need on the Buick. 

Fig. 4 — Franklin 
exhaust method of 
^heating the mixture. 
Note jacket which 
encloses intake mani- 
fold through which 
exhaust gas passes. 
A cut off is provided 
when engine becomes 
very warm. PI and 
P2 pipes are left 

TO C*¥l HtAt/ 


Fig. lA — Hot water heating of mixture m em- 
ployed on the Oldsmobile 8 cylinder V type encine. 
Note the hot water circuTatei 
throuffh a jacket around 
the inlet manifold. Thia 
principle is more effective 
than heat around the car- 
buretor. Exhaust heat can 
be passed through this jack- 
et inatead of hot water, 
which will heat the mix- 
ture quicker. (see alio 
pages 82. 155 a^d 158.) 

Fig. 7 — Stuts hot 

water heated intake 


Mur lOupr 


Fig. 8. — Kh'otric Primer. 

Fig. 8 — Heating the priming mixture electrically; 
a pipe connects with gasoline supply. Primer is 
screwed into inlet manifold. Suction of piston 
draws in raw gasoline. An electric heating eoil 
connected with battery heats the gasoline as it 
passes into manifold. (New York Coil Co.. 888 
Pearl St.. N. Y.) 

U^*yiT. .[KTAlt 

Fig. 9 — "Hot-spot" heating of mixture by plac- 
ing the exhaust manifold adjoining the inlet mani- 
fold, but only as part of the inlet manifold is 
heated; the upper part. The idea here, is to pre- 
vent condensation of fuel. The liquid particlea, 
when they reach the top of the vertical passage, 
do not swing to the left or right with the gas. but 
go straight, since they are heavier, until they strike 
the hot spot. 

OUST NO. 78— Methods of Heating the Carburetion Mixture. See also pap^o 187, 1S)1. 
lee pes* 744 for a home-made heated inlet manifold, ind page 735 for "air and water" injection. 
Sea elao. Packard Fneliser. page P55. 

— - 3"STEucT::y ntjiber twelve. 

*Carburetion Es^ciz^ yUthcds, 

- :ize 157) is 

-ii- f:r heating the 

:i page 155. 

■:- -.iliii^all night 

_.k> as if ex- 

-ijine is run 

- *"Lling, the 
-: • *™-:rinie and 

'- ::: :e a water 

■ " • a::.] inlet 

r '. .- repiilator 

f 1 v-:ry good 

--■-- oan only 

,• . : r.r or pump 

i.-rr: No. 3). 

- ; jf 157) is 
.:-- -LiT tie mixture, 

>-. - rage 156. 

- - : irrund the 
.' .z'. the inlet 

^ izhfiust pipe 

I S flexible 

" ! -r should be 

:*■:■:. ^YiT a^ outlet a copi»er pipe with ^ 
-'• S" opening should be connected and 
.Mrrirl to bottom of engine to emit the gas. 

Waztn air may be drawn into the main 
air supply by means of a flexible pipe con- 
r-ootirn and hot air drum or stovo as per 
laje 159, in order to heat the air as it is 
•irawn carburetor. It is advisable that 
a temperature regulator be provided so 
cooler air can also be drawn in after engine 
is warm'^d up. 

Priming by ** choking" the air supply, is 
the method now used to a great extent for 
starting, which usually consists of a valve 
in the warm air supply which can be en- 
tirely closed thereby causing an increased 
suction of gasolint'. After engine is started 
the choke or valve is gradually opened as 
engine is warmed up, at which time as much 
air as possible to prevent missing, is pro- 
vided. Priming should be done sparingly. 
(see page 205 u 

r«rhnretor Attachments. 
. :•• :o the cyl- gines. a duplex type of carburetor is used 
„- - Irf. 160, 164. and is placed between the cylinders to one 
• -.:rfi vertically ^"'^^ manifold. See fig. lA, page 157. 

'-^•' 160. Air control devices and hot air attach- 

:y*.:r.der en- raents. see pages 159 and 157. 

-T Z: Determine Size Carburetor To Use. 

- *"i:u!d be de- than could be secured through the metal 

-; ; • .ilve opening carburetor by conduction. The temperature 

:: rylinder dis- of the metal part of carburetor becomes so 

• ** & :rue measure low that water condenses on it, and. in 

•. :4rburetor can- some cases, is in the form of frost. These 

-• % rylinder than results are produced by the use of a car- 

■*.':z:zz will allow bur^tor too small for the engine. To meet 

these conditions, some makers provide means 

for heating the air supply, as previously 


! :-: much pas- 
fT "ir-e to deliver 
^•.'2 one having 
- • i: of the valve 
: . r::."»r would not 
;-• :r.e power of 
jt weak mixture. 
5=all the engine 
• ■ : ower, as it 
•■ :\rge at high 

>•- ;.'.l for the en- 
li while in opera- 
'.": y.eoessary to ef- 
r.^ CAfloline is more 

: entering air or 


It follow? that the carburetor of projier 
size should have its passage area equal to 
the valve opening of the engine. In mul- 
tiple cylir.dor engines this area is equal to 
the valve opening multiplied by the number 
of suction strokes which takes place simul- 
taneously, dotormined from the sequence of 
cranks, also s«'e chart 81. 

It will spell failure to fit a carburetor 
with a 'argc ;ot and opening, to an engine 
in which tbe exhaust closes very early, be- 
cause, the surplus gas cannot be expelled as 
completely, as with an engine having a very 
late closing exhaust valve. 

- : bile engines is 

* -T-.'.'.ed from min- 

. . VM -ti It gives ott gwei 

- ,.*:. r.ves off steam. \\ hen 

• ■•' b;'.-.Mne liquidf, end 

• ,••■■ • Vetirinr, naptha. etc. 

./...-» >*?wf«n them is their 

, ; ••: turns to vapor, or 


. , «-.'»: aifference in the 

/ - -,:*r..-o. thick, heavy oil 

- n-. -srv temperature of tnf 

% i tw'hcn heated. 

.^ ^-.asi:* a: the ordinary tern- 

::;v^'4tSr :t i. »n 'olat.le that 

5S- 7>f« 160. 827. F31 on 

it n:;;»t I:- kev- »- air !!.:• i ta:.ks. fur it w<miM 
iT.tircly evav «-""-»•** '•• le't expcscl to tl>c air. He 
»-i\:<.» of thu vo'..%:i:ity. ca.ii'li»-.o must W han.IIcd 
»■!'• t'src tc :r%i!!t tlri»8 nr.d . xMlo^-ionn. It 
#h»v:'.*. r.oer be har. i'.e.l near .i:. flanw. 

•Befulu of nsis; low gravity gasoline: A low c' fa»c»i'.r# * ri", rrodaoe ri>«^r r.»iultji in auy 
i.iryart-tor. l'»iff:c".;'.:y in Rt.irtir.k: is tlio main dis 
A :v»r.t*f^e ir. :!» use as it i» not as volatile at a 
hifh p-avitT. 

Znfertcr. or too mach fasoline 15 cenerallv indi- 
fate.: b> * Mac* tmcky eshaast an.l .lisaKrioable 

Vh«& a Ifw gravity of gasoline is trned soaie 
nethc^ Ut raportfing maat he employed, a^ ex 
rU.-e.i .'- ^^*f< '^'^ 



An Ideml Heating System. 

Fig. 10. — Combination of heating the mlztnrt 
and heating the air; exhautt manifold adjoine the 
inlet manifold which heati the miztnre as It 
enters cylinders. Warm air is drawn around 
upper part of carburetor, admission of which 
is controlled by throttle which keeps upper part 
of carburetor warm. Warm air is drawn in main 
air supply which heats the air. A temperature 
regulator controlled from dash, admits cool Alf 
into main air supply when engine is thoroughly 
warmed up. 

For starting, the lower air opening of carbure- 
tor can be closed entirely which "chokes" the 
air and causee gasoline to be drawn into c^rlln* 
d<>r until engine starts. This system is used on 
the Nash trucks and is an Ideal system. 

Air Heating Methods. 
In chart 78 methods of heating the mixture as it parsed into combustion chamber of cylinder was 
*" '" ^ " ----- - ^- ... .^ ^1^^ j^^ "choking" the air entrance, to supply 

eciiTWuis TW)« nASi> 

traftttfd. We will now take up methods of heating the air. 
a priimiiic mixture for starting. 


Hot Air Darlea. 

Fig. 1— Utailralig 
a modem prliMlito of 
heating the air •• tt 
is drawn into Ika 
main air tupply 
opening of carbure- 
tor. A hot »ir 
drum, also called a 
"store." is fitted 
around the eahauft 
pipe. Not close but 
placed so that air eas 
be drawn In whera 
arrowa indicate. A 
flexible tuba than 
permits tha air to 
flow to air opaslng 
of carburetor. 

Fig. 1. — Showing how warm air 
ta AxKvn into carburetor. Alao 
htm "ckokar" or air Tatva cuts 
off the air supply causing gaso- 
line to b« dravn into crlinder. 



A valTe is proTlded, called tka "air ralvu," also callad a "damper" 

r "choker." which can L« ott^nmA or ^ItttLmA Kv «h« **&!» vamwIa*^*** * 

lerer. naually placed on the steering column or dash. This lerer opar- 
ates a butterfly type of valre in the air opooing of carburetor. 

Choking Air Supply to Start Engliia. 
WWb atartliig angina, this air Talra la doaed wUeh eoU air tha air 
supply to carburetor and causae aa l a cr aaaad aucUoo of gaaoUaa to an- 
tar cylladcr (or an extreme!/ rich mixture;. This gives the lalClal 
primiag for sUrting. Immediately engine is sUrted. the air valra la 
slightly opened to admit air. As engiae becomes warmed up the air 
▼alTa la opened more and more until foil op«o. or where engine nuM 
without miasing or Jerking which la common during cold weatbar. II 
ia well known that engines will niaa when first starting, dna to tha 
gaaoline particles being nc^rar'oratcd. dne to la<k of heat, but after 
aagiaa ia warm the gaaolice becomea vaporixad and the anfiaa rwm 
without SBlssicg. *The idea is to ma on as much air aa poaalbla a* aD 
times, therefore open the air ralre to the point where miaalag will aal 

With thia prtscipla warm air vUl ba 4lravD teto eathurator m afl 
Umaa tha atr valva la apau, bat after engine Is tborovfbly warm and 
especially ia summer, cool air can be drawn ia — at opeaiag "eald air." 
This can ba closed e£.tire]y in the winter or regulated by hand ac«ard' 
ing t4> tha weather. 

Teap4rat«:re Eegulasor. 
Fig. 2. — ^Tcsapexatara reguhMar as u sad on the Zenith carbureiar la 
skews is this i:>sst7a::o& It is placed oa the air opeolag af carbara' 
Tte air eoitro! lexer or air reg^ilator operates the "air lerer" ar 
*a" Ta;Te 'Ty. admitting more or !eas warm air. 
m tempt r ITU re of this warm air actcrtag eaihurator caa ba ttt^ 
by a ba:^d 'Zt pls'ed uTr>-^rLi the op«^.sg. Th* o^eaxaa petmMa 
caol air to be crava a a::.d t^e r:«e of this o^r^ is gwreraed aMra ar 
leas by the '.e9;«ratire is, r-^cr^^.r. t'&e o;»<aiag 'Z; is ua^^ally wOm 
epem. hrst €l'j%itd core or >it <i%n£g ^'A weatcer. 

1 1111 w typa of tamperat^re regaiator Is shawn la ig, 9 — it ia the 
type aa*^ 02. ti* E.*>::«7 •ari.-r*^'^r. The pris^rple ;§ i.a.lUr exeept. 
^u a^icairg Z. .i ^cclrollt-i fr',= the das:-.. 

V^t a fev wards af 

Islet Kj 
T>is aii;er: .1 treated fjs, y^tm. 92 %rA IM. 

Tha htlct ftsrfca .t ''.r.-*-^*^ v, tz.t >'^ 
vulrea. Cri a ftir:? r:.--ier «cr.::e ;t .• es-y 
epm-Tga :^ i^e =^^.5",.! ai Ti»r* 
mg. G. pft €4 arl If I s'vct*,. 
the fasge aa si.'i-vr a'&cie •%; 

CT-fr^Iigi '.f lie Saiit 

::t<'.eccar/ v» iare rma 

are :»♦ ir.*t y^rzt v.g*^«r aee 

"ie <ari-.rei(tr it t-.e^ ^•i1i♦frl•ii to 



as if'/.-it >'.\x *JXJk 

.1 *.'.Z.Z,*r''L^ft :£ ti* 

2« r,.«.il«y Mxt a t^a 

to nz tfa-v a&d >-xa hard .t ;s xee^aiary 'JLat . 
riirtrir arl -•-.-*? »ii .iX aji.5',jl sa<t •^ 
jTr-&-. »-r -•a-tt See Jie#aa 

ghw pan eceTTga >e acn^.ue:/ tigSti. 
1— aa*i :r: 

tks JJr SBtcrtac Carfeorrtor. Surisg sj ' C^i'Mcac" 

--* V *.-. -^hV 



Fig. 1. 

"»• CHAM3tA 

TO A^Jijsr TftAernf itvi*^ 

lu^kc, 1^-Hen luTel Vftlv4 
ituchi in lAMh 

(Jrtwi in wait r 'if car- 

Ford Carburetor. 

The illustration above is that of the model 
**Y" Kingston carburetor used on the Ford. 

Float Principle. 
When gasoline and air is drawn into cylin- 
ders bj suction of piston, the float auto- 
matically lowers, thereby opening the float 
needle valve permitting more gasoline to enter 
the float chamber. When engine is not run- 
ning the float chamber fills up, causing the 
float to rise, thereby closing the float needle 
valve. This prevents more gasoline entering 
which would cause overflowing and dripping. 
If the float happens to become loose or low- 
ered more than intended, it would not cause 
the needle to cut off the gasoline supply — 
hence dripping would result, (note dotted 
lines indicate the gasoline level.) 

Priming Method. 
The damper or ''choker" or "primer" 
matliod for priming or feeding the engine 
more gasoline for starting in cold weather, 
is operated by closing the damper or "air 
valve." This is used principally during cold 
weather. See Ford carburetor, pages 798, 802. 

Heating the Air. 

The air is taken in at the "air-valve" 
opening. A hot air pipe is shown connected 
which admits warm air to be drawn in from 
around exhaust pipe. This is a good example 
of how the air Is heated before being drawn 
into cylinders. It will be noted that there is 
no auxiliary air valve on the carburetor. 
Heating the Mixture. 

This lllustraUon (fig. 3) is that of the 
WUmo exhaust heated Intake masifold, de- 
signed for Fords and other cars. It is a good 



example of method 
for heating the mix- 
it passes into cylinders. 

The carburetor connects with the lower, or inlet 
part of the manifold — exhaust is upper part, with ft 
plate between. By completely raporiiing the gaso- 
line no residue is left to seep into crank case to 
thin the lubricating oil. The Whittier Co.. 2415 So; 
Mich. Avt«., Chicago. 111., mnfers. — who claim an 
increase in mileage on a Ford. 

The principle of using kerosene is similar to that 
of using low gravity gasoline. It should be heated 
in order to obtain vapor which will mix with air. 
Kerosene, being of lower gravity (thicker) than 
gasoline, it must be heated more. However the 

A Ford Kerosene Burning Carburetor. 

9c [%^€^^^> o> 

Fig. 8 — A kero- 
Mne carburetor 
for the Ford. 

gasoline we are now being supplied with requlree 
heat also and this principle will ex)»Uin a rery 
good type of exhaust heated intake manifold, which 
would also be satipfaotory for present day low 
gravity gasoline. 

The hot-pin manifold, this particular one is termed, 
because the pins as shown, which are inside of the 
inlet manifold, turn the wet gasoline or kerosene 
into a vapor as it strikes the hot pins. 

The inlet manifold is cast directly into the ex- 
but of course, the exhaust gases do not pass into the 
but around it which soon warms the intake manifold. 
To use kerosene it is first necessary to use gasoline to start on. There- 
fore with this system there are two carburetor bowls. One on the left 
is for gasoline, and one on the right for kerosene. The engine is started 
on gasoline, from a small auxiliary gasoline tank with which it it con- 
nected. After starting on gasoline and running for a few blocks, in 
order to give manifold time to heat, the gasoline is cut off and the kero- 
sene side of carburetor is turned on. An operation controlled by a ape- 
cial designed throttle lever. Manufacturers are Kerosene Burning Oar- 
buretor Co.. 2015 Michigan Ave.. Chicago. 111. 

haust manifold, 
intake manifold 

**T NO, 70— Principle of Carburetor Action and Hot Air System for the Ford. 
' Manifold. A Ford Kerosene Carburetor — see also pages 827, 754. 




-csBtinned from page 158. 

A tMt by hmad: To aaeerUin how near koro* 
jma are fettinf, pour a little faaoline in the 
When it eraporatea alowly and leavea a 
. depoait, it ia a rery low grade. When it 
evaporatea rapidly and leavea the hand dry and 
clean, it ia a higher grade. This fnrniahea a fairly 
reliable teat. 

TMtliif gMoUne with a hydrometer was the 
method used a few years ago. It was used as 
fallowa: Fill the glass tube with the_gasoline. 
insert the hydrometer, which will float. 'Ae grav- 
ity of the gasoline is determined by the depth 
the hydrometer sinls in it. A seale is gradaated 
aa the upper portion of the hydrometer and the 
lerel of gasoline indicatea the specific gravity. 
The aeale usually runs from 60 to 80. Oaaoline 
■nder 60 test ought not be used. It averages 
about 64 to 68 and the better grade 72. 

Qnwttf U no longer an aocnrato test of 
tte aailti of the fluid, the only really accurate 
teat being from a maximum and minimum boiling 
paint. It ia, of course, not practical for the aver- 
age owner to make such tests and the best rule 
la to purchase from a reliable diatributor, who 
haadlea gooda manufactured by responsible dis- 

Ifoat af the gasoline today sold for motor ear 
■■a diffara from that of aeveral years ago in that it 
ia not all of one grade, but is a compound or blend 
of the different petroleum elements; some of it be- 
ing very light and volatile, while about one-fourth 
of it may have a boiling point higher than that of 
water, and is correspondingly difficult to convert 
mto a vapor. 

To iisa tills fnel it is necessary that the whole 
aartwzalor and intake manifold system be thor- 

oughly heated. Without this heat the carburetor 
setting will have to be changed and made richer 
than necessary, while the extra heavy part of 
the fteel, not vaporised, will bum alowly in the cyl- 
inder, forming carbon, aooting up spark plugs, 

There is, of course, a period of time just after 
starting the engine cold, when the rich mix- 
ture will be necessary (and can be furnished by 
the dash control), but the control should be re- 
leased as soon as the engine becomes warm. 

It is also adTisable, while the engine is cold, 
to avoid opening the throttle fnll, aa the fnai Ta- 
porisea much more readily in the suction or partial 
vacuum which ezista in the manifold while the 
throttle is partly or completely dosed. 

In very cold weather it is advisable, instead 
of readjusting the carburetor or using the dash 
control continuously, to cover part of the radia- 
tor surface so that the normal temperature la 
maintained under the hood. 

In some parts of the country there is so great 
a range in the constituents of the gasoline sold 
that the lighter or more volatile fractions may, in 
warm weather, boil in the carburetor, under nor- 
mal operation of the car. In this case, the hot 
air supply to the carburetor may be disconnected, 
while care should be taken that the gasoline supply 
line from the tank to the carburetor does not ap- 
proach the exhaust pipe, cylinder walls or other 
heating influence. 

If the gaaoUna should catch flra^ do not try to 
put it out with water, for as the gasoline will float 
on water, it will only spread the flames. Damp 
sand, flour or a wet blanket will smother the Are. 

*IiOw Qravity vs. High QraTlty aasoline. 

Thm proper gravity of gasoline to nsa is gov- 
•mad by conditions. In the summer a low grav- 
ity vaporisee much easier than in the winter; 
tksrafora the engine starts easier. 

A great many claim the low gravity givea as 
gaad or batter results than high grade— probably 
It doea, aa there are more theat units per gallon, 
bat aa a matter of easy starting and absenee fmm 

carbon deposit, the high gravity is preferable, un- 
laH the carburetor has been properly adjusted 
aad priMiag and heating methods provided, (see 
paga 166.) 

mXk tka high gravity we have a high "flame" 
rata (laixtum bums npidly), whereas, with the 
law gravity we gat a higher combustion heat, but 
aiawar "flame" rate. With a high flame rate 
the adztura bnma rapidly — preasure rises quickly 
aad teparta a powerful puah at commencement 
•f stroca, but falla away •<iually quick as the 
siraka progreaaea. 

mSk low craTlty gasolina, the reverse occun. 
The axplooion generates slowly and does not im- 

part a violent shock, but with a retarded flame 
rate, the preaaura predomniates through a much 
greater proportion of the atroke. The resulU 
are obvious, with high speed, as racing, the high 
gravity is best. For medium speeds, where 
steam-engina like power ia required, combined 
with fuel economy, low gravity ia bast— ^irovid- 
ing the carburator has been readjusted for the 
low gravity fuel - and proper heating arrange- 
ments provided. 

Owing to the great amount of carbon in low 

Sravity gasoline it ia very neceasary that the car- 
uretor be properly adjusted. 

The startfng win ba mora dlfllenlt with low 
gravity, bnt^dth the use of a primer and hot air 
arrangement, this trouble can be overcome. 

It is a well known fact that an engine, aapa- 
dally an old one with looaa baaringa and alaek 
pistons, win run mnch more qniatly on low grav- 
ity gasoline. The reason is due to the slaw 
flame rate; the preasure is gradual on the pia* 
ton head and preeses rather than slama. 

Fuel Troubles. 

Water in gasoline: Is indicated gen- 
erally when the engine runs irregularly and 
laally stops. This will often prevent start- 
iag of the engine. Water is frequently 
present in gascmne, and particularly when 
the tank is low, is liable to get into the 
pipes and carburetor. The drain cock at 
the bottom should be opened occasionally to 
let off the water. 

Ia eold weather,* this water is liable to 
f le et s, preventing the action of the car- 
boretor parts. Ice in the carburetor can be 
SMited only by the application of hot water, 
(or some other non-flaming heat), to the out- 
side of the float chamber. 

OMoUne onght to be strained: Many 
carlmretor troubles would be avoided if 
mmm care were taken to free gasoline of all 
Art before its entrance into the tank. 

*II la taspartant that the low gravity gasoline be heated, otherwise condensation takea place in «iV 
"-" — 205. tSea pages 861. 909. meaning of B. T U. 

When filling the tank use a strainer funnel; 
chamois skin makes' an excellent filter; if a 
wire gauze be used it should have a very 
fine mesh. In the absence of a strainer, 
funnel or chamois use three or four layers of 
fine linen fitted inside an ordinary funnel. 
Never use the same funnel for both gasoline 
and water. (See chart 80.) 

Old gasoline: Left in carburetor for some 
time, when car is not in use, will lose its 
strength. If the engine should not start 
easy, then drain the float chamber. 

A strainer should be on all gasoline tanks 
or lines as water and sediments being 
heavier, always settle at the bottom. 

Addresses of carburetor manufacturers 
classified under the type carburetor they 
manufacture is given on page 162. For 
detail information catalogs are of value. 



Oasoline Troubles. 

Tha tank of a fuel ■jftom ia atwava prorldad 
with a amall bole, oanaUj drilled through the flUtng 
ea9t aa per V, tg. 1. by which air may enter to re- • 
plaee the gaioline ai it is drawn off. 

If this hole becomee cloned with dirt the f aso- 
Une in flowing out will tend to create a vacuum, 
and the flow will stop. 

The outlet pipe should project slightly aboye 
the bottom of the tank, so that water and airt nSay 
settle, and not be carried to the carburetor — a filter 
screen should also be provided. 

If gaaoUne drlns ftom feed line, examine con- 
nections A and if it drips from carburetor it is 

likely due to float 
V needle valve not 

seating properly, 
see page 166, 167. 
. „^ . - Gasoline leaks are 
("l^* I ranrW sometimes diffi< 
^^ cult to locate. 



» ia aaid that atakie 

when atraJnlng through 
a spark is liable to igni 
is grounded to tank thia cannot occur. 

will be ganeratad 

and ehamola and 

lite the gmsoline. If funnel 

Broken gasoline pipe can be temporarily repaired 
by wrapping with tape. 

Air leaks oanae miasing: If engine persists in 
missing and is not the fault of ignition, then look 
for air leaka- in the inlet manifold (per flgs. 8 A 4 
and page 717) examine gaskets and see if a crack 
is in the intake casting — providing the trouble is 
not in the ignition. 

Xioaks in the intake pipa. gaakat ia a vary com- 
mon eaoae for miasing at tow aPMda, and is best do- 
tectel by letting the engine run at the missing speedk 
Take a squirt can full of gasoline and squirt around 
all the intake pipe joints. If you detect any differ- 
ence whatsoever in the running of the engine there 
is a leak. 

If gasoline fails to flow to carburetor, see that 
V, flg. 1, is open. If this is open, then examine 
flhar screen at bottom of tank. If this is open, 
then remove pipe B and blow it out. If this is open 
then take carburetor apart and see if clogged up 
with waste, or sediment. 

Gasoline feed pipe connections should use special. 
unions as shown in fig. 5 and page 608. The 
threads are very fine and can easily be crossed. 
Therefore use . precaution to not ' ^cross-thread' ' 
when joining a gasoline pipe coupling as at (A). 
the • 

Cracked flang** (par flg. 4) can be repaired by 
having welded by oxy-acetylene process. " 
164 and 717, for kind of gasket to use. 

See page 

In B 

threading is straight and correct, 


Qasoline Taxik and Oange. 

Flf . 27. Bhowa the gasoline tank naed on the 
Btadaoakar-aix. Note the conneetion to vacuum 
tank, also the gaaoltne ganga mechanism. Aa the 
tank is fllled the float riaee which causes bevel gear 
on float-rod to turn rod connected with gauge needle. 
See also, page 614 and 828 for other type of gauges. 

.im TANK ntLt* np% 

Oasoline rota rubber rapidly and should not be 
conveyed through a rubber hose, nor should joints 
be nacked with rubber. Shellec or soap may be 
nMM. when screwing joints together, as it helps to 
mske them tight. 

Draining. The lowest point of the gasoline line 
on a vacuum feed system is the bottom of gasoline 
tank. Cn a gravity feed system it is at the carbu- 
retor. Strainer made of brass wire gauge is usually 
at the lowest point and should occasionally be re- 
moved and cleaned. 

To prevent water getting into the gasoline and 
freeaing during cold weather, thereby clogging flow, 
strain through a chamois. 

FIG. 87 

Carburetor Mannfactnrers' Address. 

KUfgr's of 
Stromberg. . . 
Sunderman . . 
Fletcher. . . . 





Ball A Ball. 
Johnson .... 
Tillotson .... 

Oompensatlng Jet Type Carburetors. 
Stromberg Carburetor Corp., Chicago. 
.Sunderman Corp., Newburgh, N. Y. 
,L. V. Fletcher & Co., New York. 
.Lon^emare Carburetor Co.. New York. 
2enith Carburetor Co.. Detroit. 
Marvel Carburetor Co., Flint, Mich. 
■Holley Bros. Co., Detroit. 
.Miller Carburetor Corp., Los Angeles. 
.Penberthy Injector Co., Detroit. 
Johnson Co., Detroit (used by Reo). 
.Tillotson Carburetor Co.. Toledo. 
Carburetor Co.. 244 W. 49 St.. N. Y. 

Kkifgr's Metering Pin Type Carburetors. 

Bayfleld Findeisen A Kropf Mfg. Co.. Chicago. 

Schebler Wheeler & Schebler. Indianapolis. 

Tom Thumb. National Equipmont Co.. Chicago. 

Stewart Detroit Ijubricator Co.. Detroit. 

Heath M. K. Bowman -Bdson Co., New York. 

Webber Webber Mfg. Co., Boston. 

H. A N H. A N. Carburetor Co., New York. 

Newcomb .... HoUzer-Cabot Co., Boston. 
Shakespeare. .Shakespeare Oo.. Kalamazoo, Mich. 

Kbfgr'a of Air Valra Type Oarbnratora. 

Kingston Bsrrne, Kingston A Co., Kokomo. Ihd. 

Zephyr Federal Brass Works, Detroit. 

Breeze Breeze Carburetor Co., Newark, N. J. 

Shain C. D. Shain, Brooklyn, N. Y. 

K-D K-D Carburetor Co.. Clevehmd. 

Ensign Ensifirn Carburetor Co., Los Angalea. 

Air Friction . Air-Friction Carburetor Co., Daytoik O. 

Mnfgr's of Expanding Type OarbnraloxB. 

Master Master Carburetor Corp., Detroit. 

Carter Carter Carburetor Co.. St. Louia. 

iXHAXT KO. 80-^aaoUne Peed Troubles. Qasoline Tank and Oange. 



Gasoline Feed Methods. 
There axe five systems: (1) gravity; (2) sure; (4) gravity and pumping; (6) gravity 
(S) combined gravity and pros- and vacuum, (see page 164.) 

The Stewart Vacuum and Ghravlty System. 

terminals, on which gasoline coald leek. 
Kever Up throngli a water jacket II 

la explained on page 165. A few pointers at 
te the inttallation and care will be given here. 


The top of vacnnm tank must be above level of 
gasoline in main gasoline tank when fnll, even 
when ear is going down steep grade. 

The bottom of vacnnm tank must be not less 
than 8 inches above carburetor, ^a" copper pipe 
is used. 

Do not InstaU directly over generator or wiring 

manifold is provided with one. Always tap la- 
take manifold at point as close to the tntak« of 
one of the cylinders as possible. Be careful In 
binding tubing. The air vent must be plaoid el 
as high a point as possible under the hood. Beat 
location for tank is on engine side of dash. 

On 8 or 12 cylinder. "V" type enginM with 
two inlet manifolds, a *'Y" connection is made 
at (D) on top of tank and both manifolds tapped. 

Oare and Bepair of Stewart System — page 165. 

(W) at the top. In some cases the snetlon of 
the engine is sufficient to draw gasoline into tank 
even with this plug open, but not enough to eon- 
tinue to be drawn into manifold. If. however, 
you are not able to do this, close up ping (W) 
with engine running. This will fill tank. After 
running engine until tank is full remove ping ( W) 
until gasoline gives out. Continue repeating same 
operations until a repair station or garage Is 
reached, when the leaky float can be remedied. 

(b) A small particle of dirt getting under the 
flapper valve (H), might prevent it from ■liltng 
air-tight, and thereby render tank inoperafttva. 

In order to determine whether or not the 
flapper valve is out of commission, first pHig up 
air vent; then detach tubing from bottom of tank 
to carburetor. Start engine and apply finger to 
this opening. If suction is felt oontmuoosly ^' 
it is evident that there is a leak in the 
tion between the tank and the main 

Vent Tnbe Overflow. 

Tlie air vent allows an atmospheric condition 
to be maintained in the lower chamber, and also 
serves to prevent an overflow of gasoline in de* 
seending steep grades. If once in a long while 
a small amount of gasoline escapes no harm will 
be done, and no adjustment js needed. 

However, if the vent tube . regularly overflows, 
one of the following conditions may be cause: 

(a) Air hole in main gasoline tank filler cap 
may be too small or may he stopped up. If the 
hole la too small or if there is no hole at all, the 
system will not work. Enlarge hole to % inch 
diameter, or clean it out. 

(b) Yacuum tank may not be installed quite 
high enough above carburetor. If bottom of tank 
is not 8 inches above carburetor, raise the tank. 

Gasoline Xioakage. 
If gasoline leaks from system, except from vent 
tabe, it can only do so from one of the following 

supply, or else the flapper valve is being neld 
its seat and is letting air into the tank, mstead of 
drawing gasoline. 

In many cases this troublesome eoBdlHeo ef 
the flapper Valve can be remedied by merelf l» 
ping the side of the tank, thus shaking loosa ^ 
particle of dirt or lint which has dogced tha valva. 
If this does not prove effective, remove tank 
cover, as described below. Then lift out the Inner 
tank. The flapper valve will be found screwed 
into the bottom of this inner tank. 

To FiU Tank. 

To flU the tank, should it ever becoma WiUwIf 
ompty; with the engine throttle dosed and Ike 
spark off, turn the engine over a few revolutions. 
This takes less than ten seconds, and will ereala 
sufficient vacuum in the tank to flll it. 

If the tank has been allowed to stand 

for a considerable time and it does not easl_ 

when the engine is turned over, this omj be 
caused by dirt or sediment being under the flap- 
per valve (H). 

Or, perhaps, the valves are dry. Removing tha 
plug (W) in the top and squirting a little gaso- 
line into the tank will wash the dirt from this 
valve, and also wet the valves, and cause the 
tank to work immediately. This flapper valva 
sometimes gets a black carbon pitting on It, 
which may tend to hold it from being sucked 
tight on its seat. In this case the valve should 
be scraped with a knife. 

To Clean Tank. 
Remove the top of tank and take out Inner 
shell or vacuum chamber. This will give aeeeas 
to lower chamber from which dust or dirt OMy 
be removed. Clean tank every three months. 

To Remove Top. 
After taking out screws, run the blade of a 
knife carefully around top, between cover and 
body of tank, so as to separate gasket without 
damaging it. Gasket is shellaced. 

Auxiliary vacuum pump; on some cars (Hud- 
son), a small hand vacuum pump is provided on 
dash, which if vacuum tank should become empty, 
it would not be necessary to turn engine over, but 
merely operate pump connected by cneck valve to 
pipe 0, page 165. which will create sufficient 
vacuum to draw gasoline from main tank. 

Engine primer; see foot note, page 165. 

pointers: suction valve (A) and atmospheric valve (B), fig. 2, pa^e i^s, c«kxv ««k%\V9 ^« 
groand If neceesary. The spring (E) may be weak. There is a fibre wasYvor al VioUom ol %\«ik 
•• fl oa t t his sometimes swells Bnd causes tronhle — sJways look for air leaks ftrsl — \i \aT\Y -wVW ti^\ «3U 

(a) A leak in outer wall of tank may exist. 
If so. soldering up the hole will eliminate trouble. 

(b) Oarburetor connection in bottom of tank 
■ay be loose. If so, it should bo tight. 

Cc) There may be leak in tubing length D or 0. 

Fkllnre to Feed CNisoline to Carburetor. 

Thla condition may be due to other causes than 
the vacuum system. To test; after flooding the 
carburetor, or "tickling the carburetor," as it is 
eommonly called, if gasoline runs out of the car- 
buretor float chamber, you may be sure that the 
vacuum feed is performing its work of feeding 
the gaaollne to carburetor. 

Another teet is to take out the inner vacuum 
tank, leaving only the outer shell. If you flll this 
then with gasoline and engine still refuses to run 
properly, then the fault clearly lies elsewhere and 
net with the vacnnm system. 

If the trouble of failure to feed is in i)ie vacuum 
' "^ one of the following may be the cause: 

(a) The float (G), which should be airtieht. 
may have developed a leak; thus filling up float 
with gasoline and making it too heavy to rise 

sufficiently to close vacuum valve. This allows 
gasoline to be drawn into manifold, which in turn 
will choke down the engine. 

(b) Flapper valve may be out of commission. 

(e) Manifold conenctions may be loose'— allow- 
ing air to be drawn into manifold. 

(d) Gasoline strainer or tubing clogged up 
(below K. flg. 2, page 165). Look to this first. 
Remediee for Above Tronbles. 

(a) To repair float; remove top of tank (to 
which float is attoched). Dip the float into a pan 
ef hot water, in order to find out definitely where 
the leak is. Bubbles will be seen at point where 
leak occurs. Mark this spot. 

Kext, punch two small holes, one in the top 
and the other in the bottom of the float, to permit 
discharge of the gasoline. Then solder up these 
holes and the leak. Test the float by dipping in 
hot water. If no bubbles are seen, the float is 

In soldering float, be careful not to use more 
salder than reouired. Any unnecessary amount of 
eolder win make the float too heavy. 

To^ ov ercom a the condition of a leaky float tem- 
ptfarlly vntil yon can reach a garage, remove plug 




/ : ^i-r--\ 



f^^ — lltf^entu Atiubtl )C»rt 

80iii« of iha methodi wbich b»v0 b^'eii, emplojed lor 
ail vjrHDdvr «Dgln« inlet mAnlfoMi, A moilvra GosKrtiC' 
Man ii ikoTrii ia Lvwer UluitmttoD, pAfe i2. 

ItlitsDid of driw- 
ing^ rmiollne to 
the tftok by m 
fftcQiim, tha dii- 
pbfngt" pump (D) 
ptUiips th« gmsQ 
111!*, E-conneeti 
wUta comba«tioo 
cbftfob«f of Gjl- 
ifid«r br bmkU 
eot»p«r plp«. 

Compr « i « i D 
ci.Dmea dIfttihTftcm 
(D) to work Is 
ADil lb.0 iprJDf 
foroM It bifk, 
osminf B pomp* 

{Hf IfitlOD. 

OasoUne Feed SystemB. 

Fig. 1. — GraTlty feed tank is placed aboTO the 
leyel of carburetor ao that the gaaoline flewa 
from tank to carburetor by gravity. The tank 
can be placed at any point on the c«r, Jnit ao 
it ia above the level of carburetor. 

The diaadvantage on large can where tank 
ii not cloae to carburetor; when aacending hilla, 
or on the tide of an incline the gaaoline may 
fail to flow through pipe. 

Fig. 2. Preasnre Feed — With thia aystem the 
tank ia placed in the rear and ia air ti|^t. A 
hand air pump is connected to obtain the initial 
presiure in tank. After engine ia atarted the 
exhaust gasea pass through cneck valve to tank, 
creating a presaure, which forcea the ffaaottne 
to carburetor. 

A small pipe is used for the exhanat paaaaga. 
The pipe being exposed to the air, the gaaea are 
cooled and prevent a flame. The eheek Talre 
prevents the gas passing back, as it c«n i>aaa hnt 
in one direction. 

Disadvantage — The pressure is liable to in- 
terfere with the proper operation of the float.* 

Fig. S. Combined gravity and preasnrt feed — 
gaaoline is forced by exhaust pressure from tank 
to an auxiliary tank, placed above the level of 
the carburetor — the gasoline then flows to ear- 
buretor by gravity. 

The auxiliary tank is small and is placed eloae 
to carburetor, so the gasoline will alwaya feed. 

The modem gaaoline feed ayatem is explained 
in chart No. 81A. 

Oarboretor Gaskets. 

When fitting a c^rhnretor, a gasket muat be 

Slaeed between the carbufetor dasgei and the 
%^%t on in I ike pipe. 

The beM form ef gasket la copper, interlined 
with asbestos. MuitibeAtoi or limilar material 
can alio be used aod coated on PBCh side with 
ehellac. Leather could also be u«ed bere but 
vou-ld not answer elte where,, becauae it woald 
fet too hoi. If materiai is used which has a 
rough edfe, it te important to watch that none 
of jt ceti into Che ciirburetQr pipe. 

At the point (H) where inlet majilfold ooren 
the Isiet ports p a copper gmakel most be used 
and draiim tight to prevent air leakage. Be 
sure tktiFfi are no air l4>ak:i wher^ cmrburelor 
joint the intake pipe, and where the intake pipe 
connects to the enfine. 

The air tnlet of the carburetor, it eipoaed to 
dust and dirl, shottld be placed eo that daat 
may ool be drawn in. 

The Inlet manifold.- connecttiig the ouburi^ot 
to the Inlet valve port chamber. thouM preeant 
no resistiJice to the How of the mlxtare. Sharf 
bends or turns will make it harder for the mix- 
tare to pass. 

When fttttng a car^tireitor be inre thera la n* 
vlhratlon, if there le, the result will probably 
be a broken flange a« shown In chart SO. If 
there is vibration, place a tmall iron haoget 
from a nut on engine frame to carburetor, to 
steady it and also to take strain off Intake pipe., 

Iniet MAnifoldJS. 
Engine muKifacttirera ende«vor to mM^% % 
mAolfold which will have the ie«il nnmber of 
cnrvee* and as straight and as short a path for the gat to travel 
through as posaible. 

Tli» Ideil Inlet manifold la e&illy tpedfled. It ti one ta whiek 
no unneceatary r«tifltAnce is offered io tlie flow of ibe mijitore. 

An Inlet manifold for a sic cylinder engine vhfch will deliver 
an equal mixture to each cylinder has been a problem with m*nofae- 
tureri. If the distance Is too great the gae tend* to condense- 

The Inlet manifold In mio toda7i ^ Bm«Uer In dtanetM^ tkis 
formerly, owing to the poor grade of gatoltne. The fuel te lurdOT 
to "break up^' and will not vaporise rpadilf — therefore it con- 
denses and clinci to the inner walls of maiiifold. By having 
smaller intake manifoldf, the mixture is sneked through at a greater 
epetd, whieh In a way preventa Ihia condeniattoD' 

With too large an Intake, using preaent low grade fial, after a I 
pull, the engiue tends to **cfaoke'* and nLiss until It mna i 
distance on a cloitd throttle. 

Water Jacketed manifolds ai-« now the approved method. Set 
(lower lllaatration), page 63. On many engines the intake mvdloli 
le cast right into the cjllnder. (see also page 157.} 

OBABT HO. 81— OasoUne Feed Systems— eimpUfied. AtUchlng the Carburetor. Inlet lUatMdi 
8t« index for **Air Prevsare Gaaoline Feed System.*^ •When air preaanre is nsed, if carbnretor haa a nuD Sea 
Ihe prttsore ahould not be over 3H or S Iba. With a larger float, the greater area will wlthataad aoN Tsrli 
iSleiB In preesure. 



1 lobt trotn Giii^lne XBn]K.''D 

1. T4Ailfl Lcr«r Oi 


7. »««cIaK lAxk» to J a rjJi* Ma D If old * C 

•^ VflBtVOi* Mil 

It. Ovfcr Supply Ctii»mb«T-lL. 

Li Floai-e 

IX CABollnt ia FtdAi CluicntMr 

|J'< Slliit>«il VaLve to CArburctor 

14. Wwimm Supply Pt|>e 

II l>nln Valv« -J 

4-- PI^DM CAfe&uR£TOR 
GA5 ^AaR mixture is 


A:r flLLJER0P€lil¥4O 


if> na«r c»9 


THROUGH' U TO v^*jC Uut^ 

opmT^Ke Mf^Ni(^:>v,D 
aT'H" tkrodgm nPE"c 

3^ FROM >rf<BUl^ 

The Stewart Vacuum Gasoline System. 

Referring to upper illustration it will be noted that gaso- 
line is fed by gravity to carburetor in the usual manner, by 
a grayity tank, which is combined with a vacuum system of 
drawing the gasoline from the main gasoline tank. In other 
words the same gravity principle of feeding gasoline to the 
carburetor is utilized but the auxiliary or gravity tank and 
the vacuum suction system is placed on the inside of the 
dash (usually) above and near the carburetor, so that the 
gasoline will feed to the carburetor at all times regardless 
of the angle or position of car. 

The difference in this system is that of drawing the gaso- 
line to this tank, as the main gasoline tank is below the level 
of the gravity tank. Instead of air being applied to the 
gasoline in the main tank to force the gasoline to the gravity 
tank, it is sucked by a vacuum process through pipe (D) to 
the vacuum chamber (12), thence it flows through trap or 
flapper valve (6) to the gravity tank, thence to carburetor* 

This vacuum is created by suction at intake manifold 
through pipe O, connected at N.* We know that a great suc- 
tion takes place in the intake manifold when pistons are 
working. Therefore this suction is utilized to create the 
vacuum as will be explained below. 

Principle of Operation. 
There are two chambers; the upper or Tscuam chamber and the 
lower chamber or gravity feed tank. 

When there is no gasoline in either chamber, the float and levers 
E and F, to which float is connected, dosea the valve B which admits 
air into the vacuum chamber and at the same time opens the valve 
A connected with the suction pipe which is connected with the 
intake manifold. 

If engine is working, (by crank or power), a vacuum is then cre- 
ated in the upper chamber which closes the flapper H (by suction), 
thereby making upper chamber absolutely air tight, which creates 
a vacuum and causes the gasoline to be drawn from main gasoline 
tank to vacuum or upper chamber. 

As the gasoline enters upper or Taonnm chamber the float rlaes^ 
and through lever E and F, connected to float, the valve A to intake 
manifold Is closed, thereby cutting off further suction and at the 
same time valve B is opened, which permits air to enter the vacuum 
chamber, through air vent tube. 

Air entering vacuum chamber causes flapper H to open which ae- 
tion permits the gasoline in vacuum tank to flow into the lower 
chamber or gravity tank, thereby causing the float to lower as the 
gasoline flows out. 

As the float lowers, the operation of levers E and F is again brought into action, and valve A is 
•ffftin opened and B doied, which again causes H to close, and the vacuum and suction takes place again, 
M explained above. It wfll be noted that the lower chamber Is always open to air circulation through the 
"air Teat tube,*' otherwise the gasoline would not flow by gravity to carburetor. 
•goie airkeagh connection of pipe (0) is shown in center of manifold at (N), the nsual plan is to 
' it near end of manifold, as the vacuum is greater at a point closer to one of the cylindera. 
(14) above, ia a connection used by some of the car manufacturers for connecting with hand 
' * similar to fljr* 10, page 156, for priming engine to start during cold weather. 

OBABT VO. 81-A— The 8t«wart Vacnum Tank and GHravity Feed to Carburetor, 
■n Stewart-Warner Speedometer Corp., Chicago, 111. 




ARBURETOR ADJUSTMENTS: Parts to Adjust. Carbure- 
tor Troubles. Adjustments of Lreading Carburetors. 

The principle of carburetlon is treated in 

stmetion No. 12, and it will be advisable 

start at the beginning of the subject and 

aster the fundamental principles before 

iking up the subject of adjustments in this 


Kerosene carbnretors for marine and sta- 
donarj engines, are described elsewhere in 
this instruction (see index). And motor- 
ejele carburetors are described in Dyke's 
Motor Mannal. Ford carburetors are de- 
scribed under Ford instruction. 

A Few Words on Adjustments. 

First and most important thing to learn 
about any carburetor is to let it alone as 
long as it is working properlj. Never tam- 
per with the carburetor until you are quite 
sure that it is at fault. 

Test engine for compression, see that there 
is a good hot spark occurring in each cyl- 
inder at the right time, and gasoline in the 
tank. The carburetor should be the last 
thing to touch. 

If the engine refuses to starts Arst flood 
the carburetor by holding down the tickler 
above the float chambr; if gasoline does not 
appear, look for a leak or an obstruction in 
the pipe; a closed shut-ofF valve or a dirty 

If the tickler shows gasoline In the float 
chamber look for trouble in the clogged 
spray nozzle. 

If the carburetor floods or leaks gasoline 
when the car Is standing, look for an ob- 
stmetion under the float valve or a leak at 
on^of the connections. 

If the engine starts, but a * 'popping" 
noise occurs in the carburetor when the 
throttle is suddenly opened, it indicates a 
lean mixture. Open the neeale valve slight- 
ly or put in a larger jet if there is no needle 

If the engine runs sluggishly with a black 
smoke at the exhaust, it indicates too rich 
a mixture. Close the needle valve slightly. 

If the engine refuses to idle properly, or 
lacks "ginger" or "pep" at the higher 
speed, close the air adjustment slightly, and 

if not already too rich at low speed, the 
gasoline needle valve may also be opened 
slightly by turning to the left. 

Parts to Adjust— Air Valve Type. 
The three principal parts of a carburetor 
used for making adjustments are: the anz- 
lllary air valve, the gasoline needle valve 
and the float mechanism. 


Three principal parte of an air valve 
type carburetor for adjustments. 

Some earburetors do not have auxiliary 
air valveis, but depend upon the main air 
supply opening and a "gasoline needle 
valve" for adjustment. For instance; the 
Kingston Model <<T" on the Ford (page 
160); the usual method of adjusting this car- 
buretor is to start the engine, advancing 
the throttle lever to about the sixth noteb 
with the spark retarded. 

The flow of gasoline should now be cut 
off by screwing down the needle valve un- 
til the engine begins to miss-fire; then 
gradually increase the gasoline feed by 
opening the needle valve until the engine 
picks up and reaches its highest speed, and 
until no trace of black smoke comes from 
the exhaust. Having determined the poinf 
where the engine runs at its maximum spee^ 
the needle valve is left adjusted at thi 
point. There are other carburetors which d 
not have * * auxilia y air valves " or " need 
valves" to adjust. This and other types w 
be explained further on. 

*Float Troubles and Adjustments. 

When a carburetor drips this usually in- 

'^^ fha float or float valve mechanism is 

'''hia prevents the float 

'-- For in- 

illustration, at the float screw, the gaso^ 
then reaches a higher level than the sj 
nozzle or jet — result, overflowing at 
spray nozzle. 



There are eeTeral causes for a dripping 
carburetor; either the float needle yalve 
does not seat; due to sediment under It, or 
perhaps It Is worn. If sediment is the cause, 
the needle valve can be turned a few times 
on its seat and probablj clear the obstruc- 
tion. On some carburetors, the float-needle- 
valve is in the form of a rod running 
through the float, as in fig. 1, page 148. 

If the leak is not in the float-needle- 
valve, then it is likely due to the float be- 
ing set so that it does not cut, off In time 
to prevent overflowing at the jet. Or if a 
metal float; there may be a small hole In it 
preventing it from floating; another cause 
might be due to the mechanism being too 

Float adjustment: There is usually an 
adjustment provided directly above the 
gasoline float needle valve, which will regu- 
late the height of the float. If not, then 
on some makes of carburetors, as the Scheb- 
ler, for instance, the float arm can be bent 
up or down which will regulate the height 
of float, which in turn governs the float 
needle valve cut off. 

If the leak is due to a faulty seating of 
the float needle valve, then it will be nec- 
essary to put in a new needle valve or 
to reseat the float valve seat or both. 

' f S ^ "*^^^ 


^415 SPftjirf HOUtE OPEnlHfi 


ojns Off 





UN0rK \T 

9ig. 1. Refnlating the float level in a ear* 
bnrator; gaaoline most itand in the jet barely 
below level of Jet or spray noisle, when the float 
eats off. 

By alifhtly lowerinr the float the adJoatment 
ean be made to cut off early. Railing float will 
est off later. 

Testing the Float Height. 
On most makes of carburetors, the float 
valve is Intended to cut off the gasoline 
when the level of gasoline in the float 
chamber reachee a level of about Va of an 
Inch below the top of the nozsle or Jet 
tnbe. Therefore this height or the height 
recommended by the manufacturer ought 
to be maintained. 

A simple method to test a carburetor float 
mechanism is shown in the illustration. 

In making this test, unscrew the part of 
carburetor which will permit access to the 
float and float-mechanism. Then prepare 
a device consisting of a can with a wire 
handle, a piece of copper tubing soldered to 
the bottom of the can to form an inlet, a 
piece of rubber tubing, and a nipple or 
short piece of metal tubing with a coupling 
adapted for attachment to the carburetor. 
The gasoline flows to the carburetor from 
the can, when it is held above the car- 
buretor. By watching the float ' chamber 
fill with gasoline, the height the gasoline 
reaches at the time the float valve cuts off 
can be seen. If the height of gaaoUne in 
carburetor is not sufficient, then the float 
is dightly raised so it wiU cut off later, if 
the height is too great» which can be deter- 
mined by gasoline flowing out of the jet, 
then the float must be slightly lowered, so 
it will cut off earlier. 

Owing to the variation in the suction of 
different engines on a carburetor, it often 
is found that a slight variation of the fuel 
level or a slight change in the size of the 
spraying nozzle will add greatly to the 
efficiency of the engine. The flrst thing 
to do then before attempting the adjust- 
ment of a float is to leam whether or not 
the float needs adjustment, by seeing if the 
gasoline is at the proper height in the-je^ 
when the float cuts off the gasoline. 

To locate a suspected leak in a float of 
the hollow metal type: 

If the float is immersed in very hot 
water, the gasoline will be vaporized suf- 
ficiently to force its way out through a 
puncture and the spot may be located l^ 
watching the bubbles. The float shouldi ci 
course, be removed from the water the in- 
stant bubbles cease appearing. The rem- 
edy is to solder the hole, (see page 163.) 

Qasoline Level in the Jet. 

Btromberg: Note level of gasoline in 
float chamber in the Zenith, fig. 2, page 168. 
This illustration will give the reiser an 
idea as to the relation of the level of the 
gasoline in the float chamber to that in 
the jet. On the Stromberg (H) it should be 
about one inch from the lower edge of the 
glass. This can be adjusted by removing 
the dust cap and loosening the nut; if gaso- 
line is too low, screw adjustment up; if 
gasoline is too high, screw adjustment down. 

tThe adjustment on the Stromberg "K" 
type can only be adjusted by ''bending 
the arm," as previously explained, which 
governs the float level. 

Bayfield: The float level is correctly set at 
the factory and does not require adjust- 
ment, but if it should, then the correct 
gasoline level should be maintained in the 
middle of the window in the side of the 
float chamber. 

*It la adviaable to not tamper with the float anlesi you know positively it is out of adjustment. 
Thia eaa be determined if continually leaking and test as above. Carburetors with floats as per type 
"H** Stromberg are provided with float adjuRtments. 

ton modola L ft M Stromberg carburetors, page 176-177. the height of gasoline should be 1 inch 
below the top of the float chamber. 

Cork floats aro coatod with vamlah but after long periods of time this coating may come off 
and eork boooms casoUns soaked making it heavy thus causing float needle valve to not cut off 
properly. A mlxtnro for ooatlnff la as followa: l lb. of glue, l teaspoon glycerine, 1 quart water, l<^t this 
IC. Whe - 

to a boil and add formaldehyde for quick drying. 

hen coated suspend by a string until dry. 




/Add W#vbfri«To 
Take ovi ro ritM. 

Fig. 2. Thli lUnitrfttlon ihowi tHe lerei 
of gasoline in the float chamber and in 
the jet of the Zenith carburetor. If the 
float leyel was aboye the Jet, the gasoline 
would ran out the Jet. 

Zenith: The level of gasoline is main- 
tained in the float chamber so that the 
gasoline stands 3 millimeters below the top 

of the jet, or aboat ^4''. To regulate the 
level, note the washers (L), fig. 2. 

Master: The float weights are set about 
1/32 inch from bottom of the float lid. 

Schebler: Model "L" (chart 84); the 
top of the cork should stand 1^ inch from 
the top of the bowl in the 1-inch, 1^-inch, 
1%-inch and 1%-inch. In the 2 -inch — ^model 
L carburetors this measurement is 1%-incb 
and in the 2% -inch model L, 1%-incb. 
These measurements should be made when 
the float valve is seated. 

Model R; the height of the cork float 
should be 23/32 inch from the top of the 
bowl when float valve is seated. 

Models D ft E; the cork float should be 
level and rest 1/16 inch above the top of 
the nozzle in the % inch, % and 2 inch 
sizes, and 1/82 inch on the 1, 1%, and 1% 
inch sizes. Model H; is 19/32. 

Note, when changing float level, great 
care must be taken to bend the arm in 
such a manner that the float will be at the 
proper height, yet perfectly level. 

Aozlliary Spring Tension Adjostment. 

In the air valve spring lies the chief 
difficulty In making carburetor adjustments, 
If carburetor is provided with automatic 
auxiliary air valve. This spring should be 
of such length and of such gauge wire, di- 
ameter and number of convolutions as to 
provide the requisite progressively increas- 
ing resistance to opening, while at the same 
time exerting little or no pressure upon the 
valve when it is against its seat. 

Adjustment: The needle valve should be 
set for slowest running with the air valve 
held lightly against its seat, and then the 
spring adjustment should be backed off un- 
til the slighte^st further increase in throttle 
opening cause's the valve to leave its seat. 

From this point on the only proper ad- 
justment for the air valve becomes a series 
of tests for spring strength without altera- 
tions being made in its normal length. 
That is, with the adjustment backed off as 
per the above instruction; if the spring ten- 

sion with increased throttle openings is too 
light and "spitting back" in the carbure- 
tor continues in spite of increased opening 
of. the gasoline needle valve adjustment; 
it is a pretty sure indication that the air 
valve spring is too weak and a stronger one 
should be obtained from the factory. These 
can usually be obtained in several sizes or 
degrees of tension to suit varying engine 
and climatic conditions. 

Too strong a tension on the auxiliary air 
valve spring will cause too much gasoline 
and not enough air (too rich a mixture), 
because the valve will be more difficuk to 
open by suction. Too weak a spring ten- 
sion will give too much air or too lean a 

The hand air adjostment operated from 
the seat is very popular. See pages 169, 
155. The warmer the engine the more 
air needed and less gasoline. By merely 
opening the air intake more and more, by 
hand, the proper mixture can be obtained. 

**A Few Words About the lOztnre. 

*At low speeds the mixture should be 
richer than at high. At low speeds more 
heat is lost to the cylinder walls, more 
compression is lost by leakage, and the com- 
bustion can therefore be slower, thus sus- 
taining the pressure. At high speeds the 
compression is higher, due to less leakage 
and less loss of heat. A lean and highly 
compressed charge bums faster and hence 
gives better pressures and fuel economy 
than a richer one. 

The quantity of mixture an engine will 

take, varies greatly with the speed and pull. 
At slow speeds the volume, at carburetor 
pressure is equal to the cubic content of the 
cylinders, multiplied by the number of power 

At high speeds of one thousand revolu- 
tions or over, the quantity may drop to less 
than one-half the amount, depending on the 
design of the valves, inlet piping and pas- 
sages. This reacts upon the compression, 
and hence on the mixture desired for best 

^^The phif pointi or gapi ihonld be carefully let; about .025 of an inch apart. If too eloaa 
enfine will operate unevenfj at idline apeeds and miaa at higher speedi; If too wida, will miii when 
accelerating at yery low apeeda or hard pulla. A weak apark cauaea late combuation. See index for 
"Spark Plnga." 

^^AtsMMpherio oonditiona have much to do with action of carbnretor. An engine aetma to run betiar 
at night (aea page 686) — likewiae, taking an engine from sea level to an altitude of 10,000 feet, 
iavohrea naing air in the engine cylindera at atmoapberic pressurea ranging from 14.7 Ibt. down to 
10.1 Iba. to the aquare inch. 



TlM detlffn of tli* •nglii* Iias a bemiing on th* 
carburetor dotlgn, which explains the well known 
but seemingly mysteriouB fact, that a carburetor 
fiTinff good results on one engine sometimes fsils 
to maintain its reputation when applied to one of 
different design. The system of ignition used 
also has a marked influence on the proper work- 
ing of an engine as a hot spark is. most essentiaL 

To Test the Siixture. 

If there are doubts in the mind of the 
operator as to whether the mixture is too 
rich, an excellent way to ascertain the cor- 
rect proportion 3f air and gasoline Is to 
shut off the fuel at the tank and open the 

If the mixture passing Into the cylinder 
Is too rich, the engine speed will increase 
«8 the level of the gasoline in the float 
.eh&mber is lowered, since this operation 
weakens the mixture considerably. 

Tf the mixture Is thought to be too weak, 
the float chamber can be flooded while the 
engine is running, and if this causes the en- 
^ne to speed up, it may be taken as an in- 
dication that the mixture is not rich enough. 

The proportionate amount of gasoline to the pro- 
portionate amount of air is essential. 

The novice usually giyes the carburetor too much 
gasoline by opening this adjustment valve too 
wide, thereby causing "too rich a mixture." Too 
much gasoline will not run the engine any better 
than not enough. It must be remembered that 
only a very little gasoline is required in propor- 
tion to the air. 

i^Smoke Tests. 

If the engine is fed too much gasoline, 
hlack smoke, smelling of raw gasoline, will 
usually be in evidence, issuing from the ex- 
haust. Care should be taken to distinguish 
this from the excess of heavy blne^ smoke 
which is indicative of too much engine 

Whenever any considerable quantity of 
smoke of either color come from the ex- 
haust, the engine may miss explosions due 
to fouled spark plugs. 

*If the mixture Is too rich, the engine will 
have a tendency to slow up and "choke" 
or "load up" when the throttle Is opened 
wide, and will run at a higher speed when it 
is partially closed. 

Another indication of the mixture being 
too rich will be shown in its speeding up 
perceptibly, if the auxiliary air valve of 
the carburetor is held open, or additional 
air is admitted in any way between the car- 
buretor and the cylinders. 

Such being the case, the exhaust gases, if 
ignited by holding a piece of burning paper near 
the end of the exhaust pipe, will burn with a 
large red flame similar to that of a bunsen burner 
when the air is mostly cut off. 

**Loplng: Another indication of too rich 
a mixture is when "idling;" the engine 
will run in a loping manner as if actuated 
t>y a governor; more air, less gasoline is 

Flame Test of Mixture. 
Another method is to open the relief 
cocks in the cylinder heads (if provided), 
while the engine is running and Judge ftom 
the color of the flame when the mixture 
is correct. At each explosion a jet of flame 
will shoot out of the cylinder through this 
relief cock. 

If the mixture is too poor — ^too much air 
for the gasoline — the flame will be light 

If the mixture is too rich — not enough air 
for the gasoline — the flame will be red and 
smoky. Black smoke will also come out of 
the muffler, smelling of raw gasoline. 

If the mixture is correct, the flame will 
1)e light blue or purple, and hardly visible. 
See also, page 855. 

tBich and Lean Mixture. 
A rich mixture is one in which the pro- 
portion of gasoline abnormally exceeds the 
amount of air. It may be due to faulty ad- 
justment of the gasoline needle valve, float, 
or air valve. 

An overrich mixture will cause an engine 
to overheat and thereby give rise to a num- 
ber of troubles such as; preignition, ac- 
cumulations of carbon on the pistons and 
cylinder heads, steaming water in radiator 
and loss of power and "loping" or choking 
up on slow speeds. 

A mixture is poor or lean when it con- 
tains too much air and not enough gasoline, 
a condition often due to a faulty adjust- 
ment of the needle or air valve float, a leak 
in the inlet pipe, the supply cock partly shut 
off, the spray nozzle, float valve or feed pipe 
partly clogged, or water in the gasoline. 

A poor mixture will make the engine miss 
when running idle at slow speeds, and at 
high speeds it wiU not only cause misfiring, 
but the missing will be accompanied by 
coughing and "popping" in the carburetor. 
Both this and explosions in the muffler 
may also be due to faulty ignition. 

Cause— mixture too rich: Too much gaso- 
line at needle valve. Punctured float. Float 
valve not working properly, owing to bent 
needle, or presence of foreign matter in valve 
seat. Too much priming. Primary air pas- 
sage clogged or partially' obstructed. Air 
valve not open enough, spring too strong or 
air opening choked. 

Cause— mixture too weak: Too much air, 
not enough gasoline. Carburetor passages 
or jet clogged. Throttle valve out of ad- 
justment. Insufficient flow of gasoline. 
Tank valve closed. Break in gasoUne sup- 
ply. Bad gasoline; originally, or from stand- 
ing. Water in gasoline. Carburetor too eold. 
Gasoline supply exhausted. 

'Mixture "too rich** means too much gasoline in proportion to air, or technically, there is insuffi- 
cient oxygen to support its combustion. 
''^See page 171. tSee also pages 652, 653. tSee page 623, "relation of carbon to combustion.*' 
-*«IaoadiBg np*' when nmning slow or idling is due to the fact that the air comes into the carburetor so 
alowly that the gasoline particles are not broken up fine enough and condensation takes place. Thus 
the gasoline is taken in, in a more or less liquid form and combustion is very poor. That is one rea- 
son why as much heat as possible should be applied to the air intake of the carburetor. Also do not 
let your engine tick oyer slowly for any length of time when the car is standing idle. It not only 
wastes fuel bat the manifold will load up with raw fuel and your acceleration will be anything but 
food frhen yon attempt to get under way. See also page 652. 



Um air: It is mdYisable to nm the aa- 
giiM with M mneh tir m posiible, whieh 
maftBt a ''lean" mixture. This not onlj 
means eeonomy of gasoline but prevents 
soot deposit and pitted valves (providing 
good lubrieating oil is used). 

Of eourse, when first starting or when 
eoldy more gasoline is absolutely neeessary, 
but as soon as the engine warms up, cut 
down on the gasoline and run on more air. 

Most carburetors now-a-days, are fitted 
with air regulators and heated intake mani- 
folds, as shown on pages 157 and 159, for 
this purpose. 

An engine will run on less gasoline, and 
more air, the warmer it gets. Therefore 
the reason for the air adjustment. 

"Back Finng" or "Popptng" in 
the Oarburetor. 

Back firing: There Mems to be mneh eon- 
fstion in the oie of the tenna "back kiek*' and 
"baek ire." the latter balnc ▼ery often need to 
deaeribe what happens when, in itarting an engine, 
H snddenlT rerertes its direction of rotation to 
giro a "back kick." 

Oenenlly speaking, "back-firing" is caaaad by 
weak nlztura which bnms so slowly that the 
flame continues until the opening of the admission 

vahre egain, when it ignites the ineoming charge 
in the Intake pipe and shoots back to tho car- 
buator. While an oTor-rieh miztare win alao 
bom slowly, it rarely oTer will cause back-flrfaig. 

Aiiftthar cansa of back-firing Is, of eouroe, the 
faulty timing of the Talres, or, in fact, a badly 
leaking Talre. As a general rule, back firing is 
due to one or more of the following causae: (1) 
Tcry slow explosion or weak mixture, (2) rery 
late explosion; (8) a spark occurring during the 
intake stroke; (4) the Uitake ralre partially open 
during the power stroke; (6) premature ipiitioa. 
Slow combustion is caused by a lean mixture, 
late combustion is caused by a weak or retarded 

Nos. 1 and 2 are the usual causes, while Nos. 
8 and 4 happen infrequently. 

Back-kieking la usually caused by preignition 
in starting the engine, which is due usually, as 
is well known, to too much "adTaace" in the 
spark timing. 

"Popping back" or "fitting" In tha earbura- 
tor la quite a common occurrence with carburetors 
when first starting the engine on a cold day. But 
after engine has been run for a brief period it 
will become warmed up and the gasoline will begin 
to raporise properly and run without popping back. 

If the "popping back" continues then the 
nlztitta Is too weak and mora gasoline is re- 
quired. By giring the auxiliary tdr Talre spring 
a slight increase of tension or opening the gaso- 
line needle raWe a notch or ao, to close the 
"damper" or air intake, thereby causing more 
gaaoline lupply until the popping stops, which it 
will probably do when engine is warmed up. 

Oarburetlon During Ck>ol Weather. 

Now that low gravity gasoline Is being 
nsed, the engine will have a tendency to 
miss esi^sion and run in jerks or uneven 
explosions, especially when starting. 

The reason is due principally, to the lack 
of heat to properly vaporise the gasoline to 
prevent condensation. After the engine be- 
comes thoroughly warmed up, the missing 
usually disappears. When weather is warm 
the engine starts easier, because gasoline 
will vaporize more readily and is easier ig- 
nited. Therefore during cool weather three 
tilings are essential; a good hot spark and a 
gnick method of heating and a choker or 
ydmer for enriching the mixture to start on. 

^^or starting — There are different meth- 
ods employed to inject a rich mixture into 
cylinder in order to start engine at all on a 
eold day. The common method is to close 
the main air intake, which causes raw gaso- 
line to be drawn into cylinder, which would 
be termed "choking" the air supply. After 
engine is started, it is then a matter of 
running engine until warm enough to vapor- 
ize the gasoline, at the same time gradually 
opening the choke or air valve, until the 
regular amount of air is being used. 

Wann air, of course should be drawn into 
the carburetor as per fig. 1, page 169. If a 
temperature regulator is also provided, as 

Kr fig. 2, page 159, then less cool air should 
drawn in at (Z) in winter, than in sum- 

There is a disadvantage however, in this 
Sjstem, and that is, the raw gasoline drawn 
into a cool cylinder is not idl utilized for 
combustion, but part of it forms carbon, 
due to lack of oxygen which is not being 
supplied, as* the air is choked, result, as per 
page 205. Therefore the air should be sup- 
plied as quick as possible. The problem is 
then, to heat the gasoline as quickly as pos- 

*8ea page 676 "Digest of Troubles," also foot note, page 158. 
**8ee page 798 for starting Ford carburetor in eold weather. The method employed here is te 
gasoline needle vaWe slightly in extreme cases and close damper also. Sea also page ISO. 

sible, so that vapor and air is used instead 
of raw gasoline. 

The exhaust heated Intake manifold, ex- 
plained on page 155 and 167, will assist con- 
siderably. With a jacket around the intake 
manifold, and hot exhaust gases passed 
through same, as per page 157, the mixture 
will become neated quicker. 

The choker or some method of supplying 
a richer mixture however, is usually neces- 
sary for starting. If the " choker '' .prin- 
ciple is used, it is closed only until en^e 
starts, then gradually opened. In fact» by 
using an exhaust heated intake manifold to 
heat the mixture, and also drawing wann 
air through air passsage of carburetor as per 
fig. 1, page 159, the amount of raw gasoline 
injected into the cylinders will be consid- 
erably less than if same is not heated. 
Therefore this system will provide a quieker 
vaporizing or heating of mixture and a 
saving of fuel and less carbon deposit in 

Additional Pointers on Ck>ld 
Weather Starting. 

Don't expect the angina to warm up In a aiin- 
nte any more than you expect a kettle to boil as 
soon aa it is set on the store. It takes time to 

Take Into consideration tha fact that cold aoUd- 
lllss tha lubricant In the transmission, rear azla^ 
and other parts of the car. Therefore, it requires 
greater energy on the part of the self-starter to 
revolve the engine. 

If tha clutch li in, you of course revolva most 
of the transmission gears. After a car haa been 
standing over night in a cold garage or sufficiently 
long at the curb to become thoroughly chilled, 
throw out the clutch when cranking. Tliis elim- 
inates the drag of the transmission gears plowing 
through the solidified grease. 

A good hot spark Is Importank especially In 
winter. Remember it is more difficult to charge 
a battery in winter than in tha summer, so be 
particular to see that the battery is alwaya charged. 
A quick method of starting should ba proTldad is 
order to save current. 

fAdJnstiiig tlM AT«ngtt Air Valve Oarbuntor. 


OtrbnretozB are usoally adjusted to tbe 
beat advantage wben the engine baa been 
cm and all parts are warmed np. If a 
earboretor is adjusted when the engine is 
sold, it will be noticed that it will need 
readjusting when warm, that is, in order 
to get a perfect adjustment. 

When carburetors are adjusted when 
warm, sometimes, especially on a cold daj, 
the engine will not hit just right when 
iirst starting; it will miss and not run even 
or smooth until it has run a few moments 
and is heated up, then it runs satisfa6- 

•Another point to remember, be sure the 
Ignition is right and you bave a good hot 
vark, and spark ping gaps set about .025 
of an inch (see index for "adjusting spark 
plug gaps")* ^^^ ^® sure the trouble is in 
the carburetor and not due to other troubles. 
Bee "Digest of Troubles," how to diag- 

Some tim« ago the writer was told bj ui ox- 
teeter that whenerer he wm beeten fai a "bnieh" 
he wai in the habit of itopping and adjnating hie 
carburetor nntil the engine mieeed, and tiien f\r% 
Jast a flight turn more on the gaeoline needle 
▼aire. Then, in a good many caaea, he waa able 
to catch up with and pass hia opponent. 

The best way to adjust a carburetor Is 
to arrange so that the engine may be run 
loaded while the adjustment is being made. 
One way to do this is to adjust the carbure- 
tor while the car is in motion on the road, 
tor while the car is in motion on the road. 

To test carburetor for adjustment; run 
throttled down for two blocks. When there 
is a clear space ahead, suddenly press ac- 
celerator pedal down. The engine should 
pick up smoothly, to as high speed as you 
care to run. If engine chokes, stalls, misses 
or labors, or backfires at carburetor, or 
muffler explosions, it shows the carburetor 
is out of adjustment. 

To Obtain a Slow Even Pull of 
Engine Without liisslng. 
01) Betard the Ignltton. If this does not 
overcome the missing and it is not due 
to other causes mentioned below, it 
may be due to the ignition being set 
too far advanced at retard position. 
Setting back a tooth will often help to 
run slow, if this is desirable. 

(2) Air leaks is a common cause. Be sure 
there are no leaks at intake manifold 
and carburetor gaskets, valve caps and 
above all, use good **8park plugs (see 
page 235) and see that they do not leak 
at bushing and where screwed into cyl- 
inders. Qee that gaps are about .026. 
This is important. Wide gaps and weak 
magnets on magneto ignition will cause 

(3) Interrupter points must be set correctly. 
- A clear flat surface is important. 

(4) Be sure there is a good hot spark ftom 
the battery, which means a fully charged 

(5) A coil has been known to have a short 
circuited internal connection which 
would give a spark at high speeds but 
miss on low speeds. 

(6) The carburetor should be adjusted which 
does not permit loping (too much ease- 
line). The hot exhaust heated manifold 
is an advantage here. 

(7) Engine should have good compression; 
valves ground, and proper valve clear- 
ance, being sure valves are not hedd open 
too long. Bings free of leaks. 
All this is esential to secure a flexible 
and smooth running engine. 

Leading Carburetors, — Principle and Adjustment. 

For the average carburetor, having an 
••auxiliary air valve" and a "needle 
valve'' adjustment, the following rule for 
adjusting will apply. 

First, run the engine at what will be nearly iti 
m^iwH^m gpecd in ordinary nie with the throttle 
open eonaiderably and the ipark rather late. Thia 
■peed, of course, will be coniiderably leii than the 
—^yjwiiiwm speed of the engine when running idle. 

Second: Then tarn the main gasoline adjost- 
ment, until the mixture is so weak there is popping 
in the carburetor. 

Third: Note this position and then turn the 
adjustment until so much gas is fed that the en* 
gine chokes and threatena to stop. 

Fourth: Set the adjustment half way between 
theae two points, which will be yery near the cor- 
rect position. Turn the adjustment slightly in 
one direction and then in the other until the 

Kint is found where the engine seems to run the 
iteat and smoothest. 

Fifth: Gently and gradually cover the aux* 
iliarr air inlet of the carburetor by placing the 
hands over the valve, if necessary, in order to 
exclude the air. If the engine slows down, the 
suing should be weakened, since not enough air ia 
sJlowed to enter the carburetor. 

Sixth: Next try opening the air inlet alowly 
and gradually by pushing the poppet off its seat 
with the finger or the end of a^ pencil. If the en* 
gine speeds up, there was not enough air and the 
raring should be loosened, while if it slows down, 
the mixture ia correct or a little too lean, accord- 
ing to the degree to which the speed is affected. 
If it ia found to be too lean, the aprlng needs 

Serenth: After the air inlet has been ad- 
Justed, open the throttle again and adjust at high 
speed, as thia adjustment may now require to be 

When adjusting carburetors for speed, 
racing, etc., the mixture is cut down much 
more than for ordinary use. One method 
is to cut off the supply until the engine 
m'sses when idling at low speed. Then give 
it just a trifle more and test the adjust- 
ment by trying the car on a hill. 

Are treated on pages following. 

Owing to the fact that innumerable im- 
provements are constantly being made in 
carburetor construction, it is impossible in 
this instruction to describe all the actual 
adjustments of all the carburetors 

Repairmen are advised to secure instruc- 
tions for adjustment of all the leading 
makes of carburetors from the manufac- 
turers and keep them on file (see page 162 
for list of the leading manufacturers). 

tSee "Bigeat of Troubles*' for carburetor troubles and remedies, page 576. 

*8ee page 643 for "Specifications of Leading Oars" to find the type of carburetor used on differ* 

ent makes of cars. 

**8ee page 238 for testing spark plug leaks. 

fWhen adjusting "V" type engines, adjust each block of cylinders separate, by disconnecting one 







ton^iasw Via 


Pig. 1. 

The parts consist of a 
float chamber (D), the 
cork float (C), and a 
float needle valve (B). 

These three parts con- 
trol all flow of gasoline 
into the carburetor as it 
Is needed by the motor. 

That part of the car- ^^ 

boretor which mix . the gasoHne ami air C9 
eonsisl of a mixing chamber (L), a iuȣ2lc- 
(G), and a needle valve (I), 

Parts which Automatically Bepilate 
the Amount of Gasoline Beqntred ft^sm th« 
Float Chamber to ProTlde the Ptoi^tr MixCure 
consist of an auxiliarr air valve (A) and 
lever (H), connected with needle valve (I). g' j 

OPERATION; the Gasoline Flowi frosi 
the Tank through the )s:asoline pip^t ia^ t'z.<r L^o^t. thsLmhet vD}, -^ ^-^ x^ 2. 

As the Gasoline Blses in the FloSt Chamber {D) it raises the cork Coat ^C) with it, 
which, through a lever connection, automatically closes the needle valve vB> and shuts off 
the flow of gasoline from the tank to the carburetor. Of course as the gasoline is drawn from 
float chamber (D) the float \^C} drops and raises valve (B), admitting more gasoline. 

The Suction of the Pistons Draws the Gasoline Acorn the Float Chamhcr (D) tiKoagh the 
Passages (S) into the Nossle Well (G), and past the needle valve (I) into the miziag chamber 
(L). As the needle valve (I) is raised and lowered as hereafter described,, more or leas gaso- 
line is allowed to spray into the mixing chamber (L). At the same time the snctioB of the 
pistons draw from the warm air intake (F) and the passages (J), warm air into the ■■i'Hay 
chamber (L). As the suction of the swiftly moving pistons is very strong, the air is drawn 
through the mixing chamber (L) with great velocity, aad there, coming into contact with the 
gasoline spray from the nozzle well (G), it vaporizes the gasotiAe. 

This Vaporized Mixture is then drawn by the suction of the pistons past the 
throttle valve (P) into the cylinders. The quantity of combostive vapor flowing past 
the throttle valve (P) is regulated by the position of this throttle valve, and the positioa of 
this throttle valve is regulated by the driver either from a pedal called the *' accelerator'' or a 
throttle lover on the steering pcKst. Opening the valve (P) admits more combustive xmpor 
ta the cylinders, and consequently increases the speed and power of the motor. Oosxag it has 
the reverse effect. At high speed it is obvious that the suction through the mixiBg chamber 
(L) and the warm air passages (J) greatly increases, and as it increases beyond the capacity 
of these passages to supply air, a strong suction is brought to bear upon the auxiliafy air 
valve (A). At a certain speed this suction is sufficient to draw this vidve down against the 
coil spring (O). As the vidve is drawn down, air rushes into the auxiliary air passage (B). aad 
from thence past the mixing chamber (L) into the cylinders. 

AnzUiary Air Vstr*. To take car« of this extr» rappir of air thare mvst W an extra copptT ef €■*» 
Ihie automaticallj fumUhed. This is taken care of as follows. Aa Talre lA) is depressed asnmst the 
■pring (O) it operates the lerer (H). which is hin^ at the point (S). As the J^xtr ^H> is isgnaie* 
bjr the Talve ^A) it opens needle ralre (I) admitting more gasoline to the miztore. It csa he Mcn that 
this extra supply of gasoline is always directly in proportion to the air snpply throogh tho valvv (A>. 

Dnah Pot Action. It is obrious that if means were not taken to prerent it the ralrc (A>. vhidh is 
under the tonsion of the spring (O). would close Tery abruptly if the speod of the eacino waandAeaty 
checked. It would also tend to open very abruptly if the speed of the engine was suddenly iniriaatd. as 
for instancei. when the accelerator was suddenly opened. Furthermore, the suction of the eyliadecu ia_ S* 
a certain degree intermittent between the stroke* of the pistons and this intermiaaion b«t« 

would ordinarily tend to cause the ralve (A> to flutter or vibrate if means were not takea to usmas H» 
and the Siuttering or vibratory action of the valre <Aj would result in an unsteady Sew of gSMrne 
to the cylinders, which would cause a vibratory or jarring effect in the engine. Any such ftcta 

T«»ted by a device (U) called a dash pot. Its function is to automatically insure a steady and 1 _ 

ply of gasoline vapor to take care of varying engine speeds under all circumstancea. To heM the tuN« 
(A) itesdy and to check its sudden closing or opening and to overcome its tendency to vihnft^ it in ■•- 
tached directly to a plunger (T). which operates on a cushion of aii; in the daah pot (C>. 

OHABT NO. 82— Model "B" Schebler Oarbnretor. Note the gasoline needle valTc is at 
leally operated bT movement of anxiliary air valve (A), (gee SpoeiScation of 



nodel R continued. 

W Fig. 4 and flg. 5. show two types of hand 
control! for "choking" air supply of car- 
buretor controls. Fig. 4 shows the dajll 
type and fig. 5 the steering colnmn type. 

Fig. 8. When carburetor is installed see that lever "B" 
is attached to steering column control, or dash control, so 
that when boss "D" of leyer "B" is against stop **0*' 
the leTer on steering colnmn control or dash control will 
register **Iiean" or "Air." This is the proper running 
position for lever "B." 

AuxlUary adjastment — enables the driver 
to give the carburetor a very "rich" mix- 
ture without leaving the seat 

This adjustment is connecWd directly with 
the needle valve by means of an eccentric 
in the mixing chamber (see "8," chart 82) 
to which is connected lever (B), fig. 8. 
This lever is connected as shown, to the dash 
or steering column control by a flexible 
shaft (W) consisting of a piece of spring 
steel wire numing through a brass tnba (T) 
which is anchored firmly at the carburetor 
and soldered to the body of the dash or 
steering column control. By moving lever 
of the control the steel wire moves the 
lever (B) when the lever on the daah ad- 
jnitmant is pnlled all the waj np it moves 
the lever (B) to the right, or away from the 
stop (0). 

The lever (B) turns the eccentric ("8," 

chart 82), thereby lifting tha needle Tatra 

and increasing the tension on the air valve 

,^ .1. J w J 11 • .V , spring (O). This rives a very rich mixture 

for starting in cold weather and by gradually movin? the dash control lever downward the adjustment 

can ba bronght back to normal while the engine la ninning and getting warmed np. 

This adjustment is entirely separate from and independent of the main adjustments on the carbure- 
tor, which must be properly set before the dash or steering column adjustment is used. 

In other words the carburetor adjastments proper are made at (K) and (Y— chart 82) and after 
they are properly set, then the auxiliary adjustment can be used to get a rich starting mixture. 

To adjust the carbnretor (flg. 2), turn the valve cap (K) clockwise, or to the right (right meana 
rich) until you can turn it no farther. Then turn to the left or anti-clockwise, (left means lean) through 
one complete turn.' Start the engine and then continue to turn (K) to the left or anti-clockwiae until 
the engine hits perfectly on all cylinders, at the slowest speed possible. Advance the spark lever two- 
thirds or three-fourths the way on the sector and then suddenly open the throttle lever or accelerator 
wide. If the engine back-fires on this quick acceleration, turn the spring adjusting screw (V) up until 
the carburetor works perfectly. 

By taming the screw (V) np o Inward, you turn it against the spring (O) (fig. 2), which ineraaaes 
its tension thus preventing valve (A) from admitting air into the carburetor too freely. 

Turning (K) to the right or clockwise, lifts the needle valve (I) out of the nossle well (G) and per- 
mita more gasoline to spray into the mixing chamber. 

Whan yon tnm (K) to the left, or anti-clockwlse it lowers the needle in the noszle and abuts off 
the gasoline. It should be remembered that it is desirable from both the points of economy and power, 
to drtra tha car with the leanest mixture possible. 

Tfca throttla Talve should be adjusted so that when the hand throttle is closed, the engine will Just 
mn evenly on all cylinders. This can be ascertained by the regularity of the impulses in the exhaust 
when both the spark and throttle levers are set at their lowest positions. If the engine, however, should 
mn too fast, or should stop when the throttle is at lowest position, adjustment is necessary, directions 
for which are as follows: 

laooaen tha set screw (X) which locks the adJuMung screw (T) where throttle shaft enters car- 
buretor. Place throttle in lowest position. 

Zf angina runs too faat, unscrew adjusting screw (Y) so that butterfly valve in carburetor is closed 
a Uttle tighter. 

Zf angina runs too slow, screw In the adjusting screw so that valve is held a little more open. Lock 
adjuating screw (Y) with set screw (X) after adjustment. 

Vote: Warm air pipe aa shown in flg. 4. chart 78A is connected with (F), flg. 2. The exhaust gaa 
ean be connected with (6), flg. 2, similar to flg. 2. page 157. 

QBABT 2fO. n^-^ASx Ooiitn>l and Adjustment of Model *'B" Schebler Oarbnretor. 
Bchebler. Indianapolis) — see page 167 for "adjustment of floats." 

(Wheeler and 

S»«tlQii«l Vl«« Modi! "It^ S«li*bl«f OtflittTtlor — Concentric t^pe floftt, ibr^e j«t ^n^ Kprm^ adjuuiHl 

mtulUary air Istakt] v&ive. M^chnnkftUy openttd ne^dl^ vilve with tbrfl« tpeed ftdjmilm«iiii; low, 

Ooimftct cftrbiirator to Intake plp« lo tkmt 
It i«t« »bi>iit iix tiicb«B btlciv bottom of 
XMoUiiv tank^ that tbe bowl mmj he filled 
by gF&vily. For b«iit rccults^ the CArbureior 
Khoutd b« at cloie to the cylinder ma possiib^B, 
ajid is, CB^e of multiply cylii^ders. equidi»tant 
ttom e*ob one. Connect ft pipe or tube from 
^aAolLne tank to ucioo. '*u:* ' Pipe to be 
braaa or copper aad not leM tfaftn H,^til€.b 
hole* f . 

Be ffure pipe ii free from dirt — blow ft 
out. Contiect the hot water |ao1eet with 
water cifemlat^on if there h a foree cireu- 
latfon, otherwlae ft bot ftlr plpt. 3o« 
ObftTt 78. 

Before adjustitig the c&rbiiretor, xnaJco 
sure tliat your IgnlUoa Is properly Um^ 
aad that you have » good liot spark at 
each plug; that your valvea are prop* 
erly tim*d and seated, and that all con- 
nections between your intske valvei 
and carburetor are tight^ and that there 
are no air leaks of any kind In these 

m adjuatlng the carbur«t<ir, trst, 
make your adji^tmentfl ou the auxiliary 
air valve *'A*' so that it Beats firmly. 
Model L Sehebler Carburetor, hut lightly; then close your needle 

valve by turning the adjustment screw, "B,M to the right until it stops. Do not use any 
pressure on thib adjustment screw after it meets with resistance. Then turn it to the left 
about a turn and a half and prime or flush the earburetor by pulling up the priming lever 
^'C and holding it up for about five seconds. Next, open your throttle about one-third^ 
and start the motor; then <f]oae throttle flligbtly and retard your spark and adjust 

throttle lever szrew ^<F" and needio valve adjuiting screw '*B/' so that the motor runs at 
the desired speed and hits on all cylinders. ' . * 

Aft«r g«ttlnff * good adjiutraont with tout motor nmnlng ldl«, do not touch your needle vaUe ad- 
^QXtment afain, but make intrridediale and hieh epced adiustuient on the dial **d*' and *"£-** 

Adjoat pointer oa Ihe flr»t dial, ''D,' ' from fl^niro No. 1 toward fifure Ko. 3, about half wajr betw«e&. 
AdTftuce . ftpark and open throttle bo thai the roller on the track rtmnin^ below the diala ii in line 

with the Artt dial. If the motor backflirei with the throttle' in thia po^ition^ and th« upark Advanced, 
turn the indicator ft littk inori? Inward 0gure Ko. 3r or if the mixture ia too rich, turn the Indirator 
bacrk or toward fij^ure No. 1 untU yoii are efttUflcd that your motor ia runaiiiE properly with the throttle 
In thla poBitiong or at intermediate ipeed. Now, open the throttte wide nad mike your adJuitmeut on 
your dial "K" for hiffh spi-iMl in thia same manner mn you have mada your edjufitmenle for mtermediftt^ 
apeed on dial **D,'" 

Note^ — ^We Hnd in the majority of eftiee In adjuiting this carburetor the tendency ii to give too rich 
A mixture. We t^u|EC?Bt and recommpud in ftdjuiitln; the carburetor, both at low, intermediate and high 
apeed, yon cut down the fanoUnv until the motor begina to back flr^, and then in ere ate the aupply of fuel. 
m noteb at a time,, until the motor hitn evenly on all cylindera. Do nol increaee the nupply of ^atoline 
by turtiiiug' Iho needle ralve adjusting srrew more than a notch at a time, in your tow-npeed adjustment, 
•nd do net turn it any after your motor hiti regolarly^ on all cyllndprjf. In making the ad|ttBtmenta on 
the intermediate find hi|fh npccd dialu, do not turn ihe pointen moro than ooe-bali way at ft time be- 
tween the frraduated divVRlonii or mark^i »howii on the diab. 

OBABT NO. 84— The Model "L" Schebler Carburetor; Hand Controlled, Meehanieallj Opeiftted 
Jfm^d^e Valve. rSee page 167 for adjoatment of float.) 


•BATfield Principle. 

Ba^Hatd e«r1)iir«tort «re mftde In two 
liyw; mo<lel O «Dd L^ the difference b*- 
l&f: U^l modttl O ll«a • w«ter<JRGket. 

la both mod«U the sir Talre adjasv 
ttWi k«» 1m«ii «ll]iiliiAt«d, hi£b and low^ 
•p«fdi »d[jQBtio«ntB being mftde tbroufh Uie 
•Qliirol of tb« fueL 

Boib modela Ar« of the twa<Jet typ*, 
oo« i«t feAdins al low-speed »Qd both Kt 

Yh«r« sr* thro* air op«nlDCt, one flxed 
Vd o|»«rftting io eonjuoction witb the low- 
ipe t d noztle end %h« other two hsTinf aa- 
liiBati« reives linked together and op- 
mtUsg; aimnitaneouBly. 

fn* lilgU'raaM uofide li eootroUad by 

tfUclag pin actueted hj the upper au< 

alio air valve. The item of the valvt 
la connected to a piston working in the 
dmmh (Kki, from which a passage eommiini- 
«ai«a with the float chamber; the daah-pot 
«h*niber bat direct connection with the 
hiffh-apeed noxtle (see page 151). 

Whoa the throttle it opened, the ten- 
dvmej of the air vaW« to open tuddeoly 
•nd ozeeasivetyt and to flutter. i« checked 
bj the dash-pot piston, which at the 
tane time force* an extra supply of foel 
i&t« the noixle and enriches the mixture 
for acceleration; the slow opening of the 
air Talre increases acceleration by cam- 
i&C strong auction on the noxiles. 

Wben adjusting a Eayfield carbnrttort b»ar in mind that 
A RICHER MIXTURE as indicated oo adJostmeQl screw beada. 

Tha Bl^lilold daah control connects with carburetor by 
wire. When properly nsed, will render easy starting, furnish 
m richer mixture when engine is iirold. and msintain a correct 
■IstBT* under Ihe ejttreme atmotpberio chaogea. 

When carbnretor adjustments are once made, they should 
tt«« ba elianged* as the dash control wll] take care of cold 
vasthar at wet] as cold engine conditions. 


Turn screw 

tlirottlo etigliM 

Bftialng the dash control lifts the spray needle and sup- 
m richer mixture. When it is raised full distance, a 
direct passage is opened permitting raw gasoline to be drawn from fuel chamber of the oarbnrHMT 
Ibm eo^se. Control button (or lever) should be DOWN for running except when a richer mixture li davlfvd. 

!%• automatic air valve should be closed when engine ia not running or when throttled down. 

E«n«nbT that the low ipMd adjustment ia to be used only when en^ne ia running idle and posl- 
ttrtly mnat not bo need in adjusting high speed. Never adjust a carburetor uoieaa ihe «&|flQe it hot utd 
Hkm water jacket of carburetor warm. 

Adjimtiiiff B&7lleld« 

Adjvitlzig low speed: With throttle closed, and dash control down; close nosxte needle by ttm* 
taif LOW SPEED adjustment to the LEFT until block U (see cut)« slightly leavea contact with the eaai 
M. Then torn to the RIOHT about three complete turns. SI tart engine (see below) and allow it la 
rma mntl) warmed up. Then with retarded spark, ctoao throttle until engine mas slowly without stop* 
p iajf. Now, Vith eni^ine thoroughly warm, make final low speed adjustment by turning low speed screw to 
LXFT aatil angiue slows down and then turn to the RIOHT a notch at a time until enrine idlas tmooth- 
ly,. If eagine does not throttle low enongh, turn stop arm screw A (see cat), to the LEFT until it mat 
b4 the lowest number of revolutions desired. 

Adiustlnjg hl^h speed; advance spark about one-quarter. Open throttle rather quickly. Bhoold 
■Bgine back-fire, tt indicates a lean mixture. Correct this by turning the HIGH SPEED adjusting screw 
l# 1^ SIGHT about one notch at a time, until the throttle can be opened qaickty witbont backfiring. If 
'laadlitv^** or (choking) is experienced when running under heavy load with throttle wide open, it fadi' 
loo rich a mixture — this can be overcome by turning high speed adjustment to the left, 

Ta atart angina when cold: First: Oloae the throttle and pull dash control all the| way up, Seeond; 

a engine starta, open throttle slightly and push daah control one-quarter of the way down, TUrd: 
Aa angise warms up, push control down gradually as required. When thoroughly warm, puah control all 
tJha way down. When engine is warm it is necessary to pull dash control only part way up for elartinf. 

eonnaction — is conneeteil with suction end of pump (between radiator and piuop). Ha 

on other side connects with water jacket of engine or upper water pipe. A ahul off eodc la 

fva^dad for hot vrtather. 8oe that these conuectiona ara made in aucb a way that water will b« draiaad 
asl af earlmretor jacket when system is drained. 

Attack a hat air stoTa to the axhauat plpa and connect to constant air elbow of carburetor by a fias> 
IMa tube. Oonoectlona: are 6/16 inch outside diameter tubing for gasoline and water connoctiona* 

no. 8&— Adjiurtme&t of Modal **Q mis*' Bayfield OArbuxetor. 

'Spceificatioas of Leading Oars'' for nsera. Findeiaen A Kropf Mfg. Co., Chicago, mannfaetorera. 
«n manofacturcra another model called model **M," wrtta for catalofua. •Sea also paga 161. tg, t. 


^m Undt 

SirfnnlMrg Carburetor 
Models L and M. 

Th* nugurity of Stromberf 
cqidpped c&ri are UAing modvli 
L. LB. M and MB, wbieh 
MTw ail called the "plftiu tub* 
emrbiiz«tor/ ' principle of wbieb 
U cxpluaed oo pafe 177. 

Tb« Xi «D(i M models ar« tb« 
•soie carbnrertor. except, mod«l 
£i has »n **<coiioiiLi2»r" ae- 
tt«t». Tfa« L Jk M are uade for 
wmVbctl connection ■ to uitak« 
mantfold. See 6g%, I mad 2. 

The LB And MB modela mrm 
of Ihe same prtnclplo u It H V, 
except they are made for hOt%- 
aoatal eoonectio&s to latake 
ma&ifold. Tbe 2iB baa tbe 
oconomlsor iction, tame at L, 

The ecoaooiser action la m 
roUovs (fig. 1): Tbe blgb 
tpeed g^kftohne oeedU (A) U 
controlled by tbe nut (E), 
which rista on lever arm at 
close ^ throttle. Wilh 

the jrdioary dririiic 

^uar. TO 40 iiiile« per 

hour; the rolkr ^P> dropa btttt 
tbe cam notch, which portnita 
the lerer arm to drop fro* ao 
tbtt (A) de»cendi to real &p«B 
the ecoaomiaer aut> thus lowering the needle into its orifice aad partiallj cutliog off the gaioline for tboiO 
•peeda. Tbe amount of drop can bo regulated bf tho pointer (L>. which then actt at a speeiai aditiat- 
laent for tbe greateet possible economy. 

Tbe object of the eco&ooiiEer is to automalicslty graduate the gaioUno adjustmeot, which is eoa- 
trolled by the throttle. As throttle is opened tbe needle (A) ia rabed; aa throttle ia closed it lowara. 
Tbe amount this needle (A> can be raised is regulated by (L). 

To adjast tbe economlxer (see fig. t) tbe apark should be fatly rolarded And the throttle opened to 
a position which turns the engine at a ep#e4 eorraaponding^ to aboal 20 miles per hour (m.p.h.)- Tbo 
lever. L sboold then be tet one notch leaa than for tbe mixtura on which the onguie will run eteadily. 
Under ordinary conditions this would be the third or fourth notch of (L) fig. t. See also page 927. 

•AdJiuAmant of L ft LB. 
(II Put acoQomiier pointer in fourth notch. 
(2) Open throttle to a position wbicb will 
it 20 miles per hour on a level road. 

(3) Unscrew the high speed not (A) to the left 
(counter-clockwise) until engine commencM to fall 
away from too lean a mixture i then giT« ricbtr mliLtare 
bj turning the nut to the right, clockwise, notch by 
notch uutil a point is reached where tbe engine giree 
tbe beit speed for that particular throttle opening. 

(4) Then close throttle to 
idling position and adjust iht- 
Idle screw (B)» fcrewm^ in 
ward. To the right, gives more 
gaaoUne; to tbe left. less. 

(6) The daih control lever 
should be all the way down 
and tbe air horn cam plunger 
should clear the oconomiser 
levor 10 that this works freely 
as throttle is opened and 

Adjustment of M ft MB. 

(1) Open throttle about one-quarter of the way. which 
Will giro about ^0 miles per hour on a pleaanro car, (or 
one third gOTarnor ipeed on a motor truclt). 

(2) Opeo idling screw <B> from its aest two taraa 
ao that this Gi.^2not effect the high speed adjustments 

C2> Adjuit high speed needle (A> to the leanest ad 
Juatment wbicb will give the best engine speed for this 
throttle position. Inward for less and out for more 

(4) Ciose the throttle gradually and tcrew idling 
•crew (B) In as necesssrv to give adjustment for low 
speed and idle. Screwing inwartT right band, givaa bot'^ 
gaeoliae: outward gives lean. 

ThiM ** plain tube*' principle Is alto knu«ra as tbe *'PUot*^ principle and is further explained ob pagea 177. 
lAB and ^^00. 

Fig. 2 — Stxoinl»arg type H without eeaa 
omiser. Used on amall 4 eyliadef ea 
gines for trucks, tract on. etc* 

Xi ft M. 'Adjoat only wheii eagiiit 

0EABT NO, M— The StrtMnberg ''FUin Tube Carbtiretor* 
ia warm. 

Vala: all Stromberg carburetors are supplied wltb bat afr attacbmenti, similar to aae described ea paga Ifti, 

ftg. l. Also « temperature regulstor (Y» shove which rinnciple is eiplsined on page 159, fig. 2. Sea ataa 
Fi^a 927. 

Frlncipie of Stromberg *' Plain Tube" Carburetor, (Model M). 
Tills explanation also covers znodei Xi, Lfi and MB, except the econotni^r actioD, which 
la explained on page 176. 

This carburetor Is termed a ^*plaln tube** type, because the whole air supply is taken 
tlirough a single unobstructed channel of fixed size through the jet, Air valves, metering 
pins and dash pots have been dispensed with. 

How the desired mixture can be 
maintained is answered in the principle 
of introducing a small amount of air 
into the gasoline jet at (C) before it 
sprays out into the main air passage 
(E), forming what is known as an 
**alr hied" Jet. 

Action — the easoUne leftTlng flosi 
chamber (H) through (0 ftnd H). 
rises tbrough a verti<al chiinuet 
CXj> — ' not ctemrly ehown. bat 
around tuh« <J). Air takea in 
through <0>. diBcbarges iuto gftso- 
tine channel through tinaH holes at 
bot(4)ni of pafisago (0). after break- 
ing up into finely divided particlea, 
the gaBoline issues forth through • 
number of small bolea or jets Into 
th« high velocity air atreaui of the 
■mall renturi (V). This gives a 
coostaut proportion of atr to gaso- 
Uno and atomiies the fuel com- 

The accelerating veil; to aeeal- 
erate or speed up an eogtae, re- 
quires enrichment of the mixture. 
Dath pots, metering pini, etc.« have 
hertofore been used for thie pur- 

pose, but here they arc dispeased 
vltli. CouciLxitric and commuuicaiing with passage (Xj« which conducts the gasoline to the jet. is formed 
S reserve chamber, or *' accelerating weir' (F). With engine idling or slowing down, this well fills with 
gasoline. »nd whenever the venturl auction Is increased, by opening the throttle* the level of gasoline in 
thta well (F) goes down, and the gasoline thus displaced passes through small hole (O) at bottom of 
veil and joins the How from (H). on up (X), out (6) into jet. thus more thati doubling the normal rate 
9t feed. * 

Xdllng-^This is where tuba <J) action cornea io. Note that (J) is not Dientioued up to this time. 
When throttle is closed, gasoline is drawn in through hole (I) at bottom of tube (J), mixed with air 
taken in at (P) and discharged through idling jet (L) with highest degree of atomization. due to the 
fkct that a vacuum of more than S pounds exists above the throttle iT) when engine is Idling and 
throtttf closed. 

Am the Dirottle is opened from Idla, and the engine speed increases, more gasoline if drawn through 
10 and H), and it begins to discharge into the amall venturi (V>, as well at though the jet at the edge 
of the throttle. Thus the gasoline is given alternative paths, ao thai it can follow Ibe ona leading to 
lif greater suction. 

The dixrerence to be noted, between slow apaed and high siieed. Is that the flow for high speed it 
sot up tho tube (J), but through pa&sage (X), out (8) into jet. For Idlliig, it is through tube (J), out 
(L) and when opening throttle from Idling, out both, 

Tltore are two Tentori tubes; a small one (V). and a large one (VI), which produces a very high 
sir velocity (see \tmgt 147 for explanation of venturl.) 

Stromberg Model *'H/* 

Is a diiferent principle than L & M« It would he 
termed a compensating type carburetor. 

For low apeedi the gasoline is taken from sprajr 
nosxie (0), in venturi tube, through which b6t air 
passes. RegulatJion of amount or gasoline Is hf 
needle valve {A), 

For high speeds, the noszle in center of air valve, 
which ia aatomaticatly regulated by opening of the 
air valve, thus supplying the necessary volume of 

? vaseline for high speed. Adjustment for high speed 
R by (B), which controls the amount of flow of 
gasoline on high speed by regulating the time when 
the needle valve begins to open. Needle valve opens 
only when (B) comes in contact with (X). (B) la 
raised by throttle opening at high speed. Thera ii 
usually about V&2** clearance between B and X, 

Low speed adjustment U controlled by the 
n««dle valTe ''A..'* If too rich, as indicated by 
the engine •*rolling*' or **loading," turn **A" up, 
thus admitting less gasoline aod making the mixture 
leaner. If mixture is too lean, turn **A** down» 
thus admitting more gasoline and richer mixture. 

High speed adJuatm«Dt: Advance the spark, opea 

the throttle. If mixture is too lean on high speed, 

ftcrew "B" up until desired results are obtained. 

If mixture is too rich, screw **B" down, 

-—continued on page 178. 


Stromberg Model H — with vertical connection. 

CHABT NO. 86A — Stromberg Carburetor. Explanation of the Model 
'*Pttof Principle of Carburetor and Model "H/' Compensating Type, 

*L k M/* **Plaln Tube" or 



— StromlMrg modal "H"— €ontino«d. 
VoolU: B«fore fihmging a nonla, cheek vp eloeely 
on the ifnition syitem, examine all manifold and 
ralre head connections, for air leaki» as it ia ab- 
oolntelT impossible to make a earhnretor operate 
properly if the ignition is not in food eondition or 
there are air leaks in the engine. 

If, however, with the engine in normal condition 
it ia necessary to turn needle ralre **A*' down 
more than two and a half tarns, and still engine 
vfU not idle, it indicates that the primary nosile 
Is too imall and that a larger one should be naed. 

Zf it ia imposiUo to get enoiu^ gas on high apaed 
except when nut "B" is so high that there ia no 
clearance at *'X*' on idle, a higher number naedle 
shoold be used. 

If too much gas on high speed when nut "B" is 
tnmed down aa far as it will go, a lower Bomber 
should be used. 

To change the primary nouls^ take oat the needle 
TalTO **▲*' and remore nosale with a regular screw 
drirer. To remore taper ralTO on high speed, pall 
np steering post control, unscrew nut *'B" all the 
way and lift TaWe out. Thia ralre and nut "B" 
are aasembled together and ahould be wdered ia 
that way. Do not attempt to take thes» apart sr 
to change the taper. 

Vorer change nossle mora than one sise at a 
time. The nossle opening gets smallar as tha 
number gets larger; thus — a No. 69 is smaller 
than a No. 68. 

High apeed needle TaWes deliyer more gas as the 
number gets larger; thus — a number 7 will give 
more gas than number 6. 

Always install carboretor with the float ithsmbsr 
towards the radiator. 

This carburetor was used on 1917 Harmon. 



6^s*% ciOhrDOi 

Fig. 4 — ^There is only one adjustment 
and that is the metering pin, which is 
interconnected with the throttle. Or- 
dinarily the metering pin should be 
two*thirds the way through. 

Stromberg model HA — sectional ilew. 

*8t6wart Carburetor (on tlio Dodge). 

On the Dodge the carburetor (flgs. 4, 8) is on left side of engine, 
and is fed from a Stewart Tacuum tank. The carburetor is sap- 
plied with a hot air attachment which draws air from arooad 
exhaust manifold to air inlet. 

Principle: (flg. 8). The automatic metering TStra (A) rasU 
on the Talve seat (B) when the engine ia not running. As tha 
engine begins to rotate the suction of the pistons raiaea the Tatre 
(A) from the seat drawing in air around it (B to B) as Indicated 
by arrows. The suction also draws gasoline up within the Tslra 
stem as indicated by arrow from (B) which mixes with the incom- 
ing air in the chamber (O). 

The one adjustment of the Stewart is that of proportioning Ite 
Tolnme of gasolina to the air admitted. The air belnf always a 

■ * •"le TOiaaaa 

^9 t—Bom tJk* meUring ptm » vcrin 
tU mimtmr* <« th« Hewrt. Air fttt 
« 9*M*9n M amuitf tin 

fixed factor it is only necesary to adjust or regulate thi 
of gasoline admitted which is controlled by meana of the tapered 
metering pin (D). 
This adjustment is made when the engine is ninning at idling spaod. By 
turning the adjusting screw (on "daah control," see lower part flg. 4), 
either to the right or left, raises or lowers the position of the tapered metering 
pin, thereby allowing an increased or decreaaed supply of gasoline to be drawn 
up into the mixing chamber. When the proper proportion naa been detenalned 
at slow speed, it will be seen that aa the speed of the engine inoreaaea, the 
automatic metering Talve (A) will rise higher from the seat (B) and away 
from the tauered metering pin (D) which will allow a greater supply of both 
gasoline and air, in exactly the same proportion, be admitted to the cylinders. 
On the Dodga, flg. 4, the tapered metering pin is snbjeet to oontrol wItfelB 
flzed limits by means of the "dash control" ratchet^ (see lowpr part of flg. -4 
for connection), for the purpose of obtaining a rich mixture for starung. 
Should there be any reason for «4iang1ng the ued adjnstment of the tapering 
metering pin (D), it can be done by turning the atop screw adjustment an the 
"dash control," (see lower part of flg. 4). Turning it to the xlghl lowers 
the positon of metering pin and allows mora gaaoline to be admitted ta the 
spray nozile-— enriching the mixture. Turning it to the left raises pin and 
decreases supply. The throttle TalTO is in top of carburetor, (aee flg. 4.) 

OSABT NO. 87— Stromberg Model "H"— Continued. Stefwart Carburetor on the Dodge Oar. (i 
page 162, Addreee of Carburetor Mannfaeturere.) «see also page 788. 



Carter agpanding earkur§ter, the not- 
ate of tehieh U q vertical etandpipe 

The Oartar 

cAn scarcely be eaUod » 
multipU-jet, 7«t H Is » 
typical expanding deiign. 

The iUoitration ihows 
why it ia inelolded In 
thii elassiflcation In 
that iti nossle ia a rer- 
tical itandpipt in the 
wall! of which are 
drilled Tariooe holea In 
the form of an aacendliiff 
■piral and out of eaeh 
hole the gasoline iaauea. 
At low speedi, when the 
gasoline is drawn lo 
only a moderate height 
in this standpipe. the 
fael iasnes from but few 
of the lower holea. Aa 
the gasoline riaea higlMT 
in the atandpipe at U- 
termediate speeds It Ia- 
snes from more of the 
openings; and when it 

riaea atiU higher at high speeds yet more of the openings are brooght into operation. The main ^ 

•paning Is in a rertical tube surronndlng this stand pipe so that the inmshinc air passes along the pipe 

excepttag at the lower end. There Is an anziliary air ralve. The nipe or multiple Jet tube B ean be an- 

screwed by the knrled head D. Heated air can be drawn In at the side. 

At O-^ir enters: the amount is controlled by the Uttle throttle shown. Still more air ean paas into 

earburetor from the air TaWe on the left side, this supplementary supply passing upwards after mixing 

with the warm air. 

The Marvel Oarbuzetor— (used on Bnick and Oakland 34B). 
The Xarrel model E is a double Jet type whone special feet are b tba applieattoa of eiheust heat U 

a Jacket surrounding the throttle 

chamber and renturi tube, amount 

af heat being automatically con- 
trolled by the throttle opening. 

Ontalde the float mechanism this 

earburetor has but one moring 

part, the auxiliary air ralre. 

Two jaU are ased, a primary 
low speed jet and a secondary 
high speed Jet which Is brought 
into action by the opening of the 
auxiliary air raWe. 

When the engine is idling the 
hinged auxiliary air ralve rides on 
Its seat against bore of mixing chaxnbflr> tbai 
doeing off the air passage past the tall high 
speed jet in this part, rendering It i^eff«c- 
thre. At this time the air passes up throutb 
the small Tcnturi surrounding the low speed 

Am the saction of the engine Inereasefl the 
saxillary air vaWe is opened ag&iait the 
spring pressure, and the second ict eomei 
into action. 

A Choker Talre in tha main air entrance 
sUews a rich mixture to be obtained tor 
nartlng. This device may be coaLroUed 
from the dash so that when engine is cold 
It may be closed to prevent back ires, end 
gradually opened up as engine warms up. 

Tha feature of this carburetor prariously mentioned is tha exhaust heated jacket. The heat is con- 
trailed by a damper connected to the throttle lever, which damper can be set to give any degree of heat 
deeired. This is of particular importance as the qaality of gasoline is yearly becoming heavier and heavier. 
This heat damper therefore can be set to admit sufficient heat to secure good vaporisation of such heavy 
fial on low throttle, and then as throttle is opened the heat is automatically cut off, thua insuring maxi- 
■UB power at the higher speeds where heat is not necevsary to good carburetion. 

By such an application of heat the entering air is not preheated and this naturally results in greater 
thermal efficiency and power due to a maximum cylinder filling at each stroke of pistons. 

Adjuatmant; sUrt by turning needle valve *'A" to the right until it is completely closed. Then 
idjuat the air adjustment *'B" until the end of the screw is even with the end of the ratchet set 
i^faig above It. 

Next open '*A*' (gasoline needle) one tnm, start the engine as usual, using the strangler button (8) 
ta set a rich mixture at first. Allow engine to settle and warm up; then gradually cut down on "A," 
OBtU angine runs smoothly. 

Maxt turn air screw "B" to the left, a little at a time, until engine begins to slow down. This In- 
dieatea that the air valve spring is too loose. Turn it back to the right just enough to make the engine 
raa welL 

To taat the adjustment, advance the spark and open the throttle quickly, the engine should "take 
hold" inatantly and speed up at once. If it misses or, *'pops back*' in the carburetor, open needle 
▼alva "A** slightly turning to the left. If this does not give results, the air screw "B" may be tight- 
aned a little by turning slightly to the right. It should bo borne in mind, that the air valve should be 
carried as loosely aa poeaible. and that the adjustment for "pick-up" may be obtained by carrying mora 
gia with needle vaWa "A" rather than to tighten up the air valve too much. 

The best poaalble adjustment is secured when air adjustment "B" is turned as far as possible 
to tha left and needle valve "A" to the right, providing the engine runs smoothly and picks up quickly 
whaa the throttle ia open. The speed of the engine is governed by the small set screw in the throUle 
step. If the engine runs too fast, turn screw to the left, if too slow, turn screw to the right. 


Carter Oarbnretor. Tbe Marvel — (gee addressee of manufacturers on page 161). 


Tbtt Master Cvbuieter 1* & OoncenAzie Float T^pg with « rotary throttle tad borUontal fuel distHba 
ter eztendicic Mcroas the air pafisase. 

E«f«rrlnff to the Sactlonal Vlaw, the fuel distributer extending across the air passage is showo at 0. 
Tbii has a uumber of (.msU holes drikled along its length, and th« lower opening H in the rotary throttto 
D la so shaped un to uncover more and more of theac holes as the throttle is opened « At the same time, 
dne to a simtl«ir opening H in the upper surface of D, an increasing amount of gs« is admitted through 
the intalce O. Thus the fuel supply i& mechanicslly apportioned in accordance with the throttle open- 

When the Throttle is Wide Open there are no restricted paasages. 

The Air Enters through the Intake A end minces with the fuel issniaf from the small holei. asd 
'passes on to the engintu through the openings H and H'. 

The GasoUse gets to the Dlstrlbiiter tHrough the Passage P from the float chamber. A common anpply 
tube running aloof the Jower part of the distributer takes cate of eech individual distributer tube. 

One Jet for Idling. When the throttle is closed, there ia still ote distributer hole uncovered which 
admits sufficient fuel for j^low-speed or idling. 

To fieiplate the Air Supply and thus control t1-e mixture, the air damper B is placed in the air 
passage. Thi«! is eimpiv a flat piece of metsl arranercd to swing about its ba»e so as to shut off any 
part of the air. As shown, it ie set for a rich xnbttore, whereas, if partly open, the proportion of air 
would be greater. _^ . 

Model u&ed on the Saxon.) 

Oarburetor Actloa: The float cbambir main- 
tains a constant levfl or sopplj of gasoline for ihe 
motor. Gasoline flows from the feed pipe through 
an intake plus (F), thence through the float valre 
and Into thft float chamber <0). A cork float (F) 
raises or lowers the float valve, cnut regulating 
the incoming flow of gasoline in proportion to the 
supply in the float chamber. 

After leaving the float rhambor tbe gaaollne 
passes through a nozzle (K) from which it It 
sprayed in a fine stream into the mixing chaipber. 
The quantity of gasoline passing through the nosile 
it regulated by ihe "needle vaWc'* (E)<> 

The suction created by the downward motion of 
the motor pistons draws air into the mixing cham- 
ber AM) through tbe primary ana auxiliary air 
inlets. This air Hows into the mixing chamber 
around the nozile and picks up the gasoline which 
leaver the nozzle in tbe form of a spray. Thus ihe 
action of the mixing chamber is not unlike that 
of an ordinary atomiser in which the air« forced 
from the rubber bulb» picks up a eenam amount of 
the H«|oid in the bottle and sprays it out in the 
form of a flioe vapor. 
At the front end of the carburetor la Ihe aujtiliary air inlet (I). At low speeds, wben only a amall 
amount of air is being drawn through the carburetor, the «prinit iJ) holds this valve almost shut. At 
the speed incre&<ies and more air is needed^ the suction dra^s the valve further open, admitting more air 
and automat jcfilly producing the correct mixture for all motor speeds. 

When Adjustments are Necessary, observe the following instructions: 

Adjust float (F), which is right when about 9/16 in. from top ol float chamber, or when tn aboQt 
the third groove on float valve stem. 

Slow Speed Idling: Throttle valve (T> should be adjusted at (A), to get proper speed for idling* 
The needle valve (R) is adjusted only to get proper mixture at low speed. The auxiliary air adjnalment 
(L) takes care of hi^b speed. 

Hlgli 8pe«d Adjustment: ^'ith the needle valve adjusted for proper mixture at low speedy tbe onljr 

a^jtistment required for high speed may be mede from the dash, by means of dash adjustment, whicJi 
operates cam lever (L). For less air, puU the dash adjustment out. It is advisable to use as much air as 
possible, as this pives boat economy, 

Basy Starting: To start the motor, cloee staritog valve (S), which is operated by rod running to 
front of radiator, crank motor, and open starting v»Ito immediately. In starting, during cold weather. 
with the motor cold, the air can be cut down to iuit conditions, then, after motor is warmed up. the 
air may be readjusted. 

If the weather is cold or extremely humid, turn the needle valve (R) at bottom of C4^b&retor to the 
1«ft for more gas, while the motor is running, until it Area evenly under load or while the car is in motion. 
Too rich a mixture will be distinguishable by black smoke from the exhaust. Too light a mixture will 
cause uneven flring of the motor. 

If the weather is hot or extremely ary. readjust needle valve, turning to right for less gaa« 

CHAET NO. ao—Tbe Master Csfbnretor. flii Mayer. 

Master Carburetor Co., Detroit. Ma>er Cartruretor Co. Buffalo. N. Y. 


tirt* f«jioiin« from woll (J), in- 
of float chamlt«>r. 



Principle of tli« SSenlUi Carburetor. 

We shall f rst cooslder a simple type of carburetor or 
mixing valve. This consists of a single jet (G), placed in 
the path of the Ineomiug air, and fed from tbe usual float 
chamber (F), see fig. 1. 

As the speed of the engine IncrcaseHi the flow of tbe 
air increases, but the flow of gasoline from the jet in- 
creases faster, causing the mixture to become richer and 
richer. The mLcture is practically constant only between 
narrow limits and at very high speed. 

A second type of carburetor (fig. 2), is shown in which 
the spray nozzle receives its gasoline from the well (J). 

The gasoline in the well is fed by gravity only through 
compensating jet (I), and is not affected by the suction, 
as the well is open to atmospheric pressure. The flow of 
gasoline is therefore constant at all engine speeds, while 
the flow of air increases with the engine speeds, the mixture 
also becomes poorer and poorer as the speed increases. 

It will readily be seen that the second type produces 
the opposite effect from the first, while a combination of 
the two is shown in fig. 3^ will result in a constant mixture, 
when jets arc j-roperly chosen. 

This construction, further illustrated in fig. 4, admits 
of the addition of the priming tube (J) extending into the 
secondary well (P) nnd opening at the point <U) of tbe 
closing butterfly (T). With the butterfly partially open, 
the suction at this point (U) is powerful and drawe the 
well full of gasoline Into the cylindera, effectively priming 
the engine. Also by the introduction of this secondary 
well, which measures the gasoline used in running idle, m 
perfect mixture is obtained at very low engine speeds. 

The level of the gasoline in the float chamber is eet 
at the factory and need not be changed, but in case it doea, 
the gasoline level is as shown on page 168. 

Causes and Eemedy of Troubles. 
The matter in this page as well as the adjustments on 
page 182, refer to all types of Zenith Carburetors. 


3. A combiiiQiion of 1 mid 2 

[if engine does not slow down or idle: If en- 

Be ** lopes/* tha{ is speeding up and slowing 

as if fitted with governor; evidently 

much gasoline— (Is t) adjust air screw (O). 

Ind) Ipok for air leaks at manifold and other 

iiiits, S^e that jets are tight on seat, (3rd) 

%ter accumulation in the passages; remove 

'&g» under carburetor and clean (I) and (G), 

aft does not pull properly going up hill: 

engine cold, insufficiently heated. (2nd) 

too lean or too rich (irregular running 

dis In latter case) try a larger and smaller 

Btating jet (I), using the one which gives 

suits* Also jet (G) and corresponding 

ehoke tube. 

If the car does not attain Its proper speed: 

ilnf. \ inlxtur** too lean; try adjusting slow speed 

\ try larger main jet (G). (2nd) 

;h, try regulating air intake at Z 

2, page 159)* If chronic try a smaller 

Lin jet (G). 

Wb«S Iryitig 1 ii«w jet, the choke tuhe (X) must 
Jlie W Chftttftd. Choke can be removed from uppei^ 
1 •! I>srr«] by Ttmoyiaf *crew (XI) sad throttle 
#. If ilttrk, remove c»p and jet at lower part of 
<rl0r an^l uf<* a brat^i rod to drive it out. 





Pi|:. 4. Zenith carburetor for 4 
e cylinder en^ne. 


HO. 90— Tlie Zeaitll Oarbnretor: Principle. See page 159 for the Temperature Begn*^ 
«sed with this carburetor. Also refer to index for •* Specifications of Leading Cars" for*' 
(Zenith Carburetor Co,, Detroit, Mich.) 


Flgnxe 6« Zenith 
"V" type engine. 

Duplex" Oarlmretor for 

AdJasttnenU of the Zenith: There ere but two *d 
InetmeDU on the Zoalth, These edjustmeote ere pro- 
Tided to properly •*itlle" the eoipoe. With the ^Ter- 
Me cerbaretor, if maximum apeed u detired proper 
idling at slow speed is sftcriflced or vice vena. B7 
meens of edmittiog mors or less sir, however, tbrough 
the em»l] slow speed Adjusting screws (0) the Zen- 
ith carburetor will idle without "chokiog*' end "lop- 
ing' ' mad yet, the maximum speed can be obtained — 
I»roTiding. of course, the main Jet. compensator and 
choke tube are the proper iize. 

By referring to the il lustration fig. d it will he 
obserYed that a small amount of air is admitted over 
and abotp the mixture through the ptn^ (J) that is 
fed from the idling well. After the engine is speeded 
nil the mixture is drawn through tho main jet. 

There ore three ports which mnjt he of the correct 
•tM« The choke tube (X), main jet (G), compen- 
oaf or (I). The size it dttermioed hy the manufac- 
filler* according to the type of engine; four, six or 
eight cylinder, bore and stroke. After once being 
iited to carburetor then there are no other adjust' 
ments except the stow speed valv« (O) as mentioned 

If the choke tube la too large the pick-up will be 
defeetive and can not be bettered by the use of a 
larger compensator. Slow speed running will not be 
Tory smooth. 

Zl th« choke tube iJ t4^o ammU. The effect of a 
■mail choke ia to prevent the engine from taking a 
full charge with the throttle opened fully. Tlie pick- 
up will be very good, but it will not be possible to 
get all tho speed of which the car ii capable. 


Figaro 6, Sectional Titw of Zenith OmploL 
A^Main air intake, con- L — ^Lower plug, 
nee ted by fiexible 
tubing to take 

from around the hot 
exhaoat pipe, O^' 
float cover. 01*— 
Needle valve cap. 
By nnsorewing thia 
the float can be op- 
erated for priming 
if neceasary. D — 
Connects to gaeo- 
Une supply. 

Dl — Filter ecreen. 

D2— To drain. 

E — *High epeed gas 

El — Main jet aet screw, 

F —Float (metal). 

Q ^Main jet. 

QZ — Needle valve eoIUr. 

H — Gap fel. 

I — Oampeniator. 

J — Priming ping in 

idling well. 

K — Low epeed 


N — Seat of alow speed 
adJuBtment screwa. 

O— Slow speed adjast- 
ment screws, 

R — ^Spring to hold floftt 

S — Needle valre teal. 

T— Butterfly IhrotUe 
valve which la oper- 
ated by Tl, which 
i s connected h j 
throttle rod to ac- 
celerator orf hand 
throttle lever on 
steering wheel. The 
opening of T, wheo 
closed tor idling, is 
regulated by the 
stop and two »et 
Screws shown to the 
fide of Tl. 

Tl — L ever operating 
throttle butterfly 

X — Oboke tube. 
XI — Screw holding 
choke tube in place, 

If Vm main Jet la too large. At high speed on a level road it will gii 
rich mixture; irregular running, characteriBtio smell from the exhauet, firing in %h€ muffler, sontlng up 
at the apark plugs, low mileage. The influence of the main jet is mostly felt at high tpeedi. 

If the Doln lei is too small. The mixture will be too lean at high epeed and the ear will not attain 
its maxiraom. There may be back firing at high speed* but this is not probable, especially if the chok« 
and main jot are according to the factory setting. Thla hack firing ia more often due to large air leuku 
la the intake or valves or to defect in the gaaolme line. 

The compenaator (1) : From the explanation of the Zenith principle given on page 181, It *• 
readily noted that thi^ influrncf* of the compensator is moat marked at low speeds. The compenaator 
alxe ia best tried out on a hill, as regular as possible and as long as possible, and of such a slope that 
the engine will Ubor ratlier hard to make it on high gear. A long, even, hard pull of this sort toxei the 
efficiency of the compensator to the utmost, and will indicate readily the conrectneas of ita adjustment. 

If the compenaator is too Urge. Too rich a mixture on a bard pull. It will give the aame indieution 
a« for rich mixture at hisrh speed 00 the leveL 

If the compenaator la too smoU. Too lean a mixture. Liable to miaa and give a jerky aeilOQ in the 
e^r, on a hard pull. 

Bemark: When trying out or fitting new jets, ete.. teeta ahould be made ayttematically, flrat atort- 
ing the main jet. then the compenaator, then the choke. Bear in mind that when the choke ia tncreeaed 
the main jet shotitd be Incre&Bed. Water in gasoline will sometimes lodge in tube (J) and prevent 
proper idlinj;. Remove and cl^an. Tliis ii a common trouble nnteaa a strainer Is used. Temperatur* 
regulator tn>« used on the Zenith U shown on pape 1&9. fig. 2. 

CBABT HO. 91— Thfl Zenith ''Dnpl«x* 

and Airplane Engines. 

Oftrbtiretor (vertical type) u used on V-trpe Aatomobili 



Tb6 Hndaon Oaslraxetor 

If Ulnstratad below. The carbnretor li of the "metering pin" type, also eaUed 
•..-C" P^ A. fig. 1, is the meaearing pin, which ie controlled by a email lever eonneeted 
with the "gasoline feed regulator lever.'' This lever is connected with a lever on the dash 
iHiieh "measures out" the 
gasoline to be fed. A study 
of fig. 1, will make this 

The air entering carbure- 
tor is also eontroUed by 
"air lever'' on dash. Note 
in fig. 1, the body of c&r- 
boretor is not abown, but 
is illnstrsted ieparately m 
figs. Z and 2. 

Instructions for Assomblinf Msasuring Pin 
and Piston 





^e3^*?i ^ 

ism of the 
Tillotson car- 
bnretor, used 
on tho Qrer- 
land: Not« 
leTol of gaso- 

Used on the Overland engine is illustrated. It 
may be termed a double jet, variable venturi car- 

A uniform partial vacuum is maintained at the 
fuel nozzle by two flexible reeds, which are mounted 
in a cage, so designed that the maximum opening 
gives the required volume for maximum speed. 

When the reeds (flg. 2) are closed they cause the 
highest possible vacuum at slower eng^e speeds. 

The reeds open and close 
according to the speed of 
engine. These reeds are so 
placed that as they move 
they form a virtual vari- 
able venturi. A secondary 
nozzle comes into opera- 
tion at higher speeds and 
is not in use at the lower 

Adjustment; there is but 
one, which is the needle C?5r * Tp// f'/r^^/r. 

valve. High engine speeds 

VO. •IB— The Hadson Oarboretor— metering pin type. The Overland Oarbnretor (Til- 





Acljasting Jolmson Carburetor (old style). 

Indications of adjustment: (A) — lean mixture; 
(B) — engine difficult to start; (0) — **popping- 
baek" on quickly opening throttle; (D) — engine 
knocks when throttle is opened quickly; (E) — en- 
gine will not idle. 

Many mechanics can adjust this carburetor for 
high speeds but sometimes find difficulty in ad- 
justing for low speeds or idling. 

Tbe correct procedure of adjustment is as follows: 

(1) — retard spark. 

(2) — close the slow speed air adjustment screw 
(fig. 1). 

(3) — warm engine. 

(4) — see that the intake pipe manifold where it 
connects to carburetor flange does not leak 
air. Sometimes a water jacketed intake mani- 
fold will become "air-locked" and water will 
not circulate, depriving it of heat. Open 
"plug," as per fig. lA, page 157. 

(6) — accelerate engine by opening and closing 
throttle rapidly. If mixture is too rich, ac- t 
coloration will be sluggish; if too lean, it will 
"pop-back" considerably. The spray needle 
adjustment should be set between these two 

(6) — retard the spark and close the hand throttle. 
Adjust the throttle stop screw until the en- 
gine runs very slowly regardless of whether 
it operates evenly or not. 

(7) — open the slow speed air adjustment until the 
engine idles evenly if possible. If it runs 
too fast close down the throttle stop screw. 
The adjustments on the stop screw and the 
low speed screw should be made simultane- 

(8) — it may be found that the low speed air ad- 
justment cannot be opened at all. In this 
case the low speed mixture is too lean. 
Possibly the low speed air adjustment can 
be opened more than 3% turns, when the 
mixture is too rich. Do not touch the spray 
needle setting, but proceed as follows: 

(9)— disassemble the carburetor. A small ring, 

shown (fig. 1) is attached by two lu 
what is known as the lift plate. This 
is somewhat curved, and if the slow 
air adjustment can be opened more 
3% turns without obtaining good idling 
curve is excessive and the ring shoul 
slightly flattened. 

(10) — if on the other hand the air adjustment 
not be opened, the ring is too flat and s 
be slightly curved. The standard setti 
%2 ^^' from the edge of the ring to th 
plate to which it is attached. 
AdjustjLng (Model A). 

(1) — turn both idle screw and high speed u 
(fig. 2), to their seats, and set the th 
stop approximately the correct positio 
closed throttle. 

(2) — open the high speed needle 1% turns, 
permits the engine to be started. Wan 
engine up by running a few minutes. 

(3) — place spark lever in full retard position 
open the throttle until the engine turna 
« speed equivalent to about 20 to 25 mile 

(4) — turn high speed spray needle to the rigi 
til the engine speed decreases. 

(5) — then turn the spray needle to the left 
the engine speed increases and then deer 
from a rich mixture. 

(6) — turn again to the right to a point mi 
between the extremes. This is the cc 
mixture and will give the best results f« 
throttle positions. 

(7) — Adjust the throttle stop screw to the dc 
idling position. 

(8) — if uneven firing occurs correct either b; 
screwing the idling jet to enrich the mi 
or screwing up the idling jet to give a 1< 
mixture. The average setting is % turn 
the seat. This adjustment must be made 
the spark and throttle levers fully reta 
Tbe float should set evenly all around, the 

tom being % in. from the float chamber se 

shown in fig. 2. 

Principle of Johnson Carburetor. 

Th« Johnson li a "ffravlty air vatvo type." with a 
•Ingle concentric jet, in which air Talve is made up of a 
•!••▼• rising and falling by suction and grarity in cyl- 
faidrieal passage aboTO jet. 

Thef are tbrt ifgai of vaflmun; one is the spaca be- 

tween the throttle and strangle tube, the second, i 
strangle tube itself, and the third, in the space 
the plate onHhe bottom of the air TaWe sleere. I 
moTtng the location of the idling adjuitment (in f 
the flow of gasoline for this parpoce has been bi 
into a sone of greater ▼acunm and hence bett^ id 

'T VO, IMfr— JoluuKm Oartraretor. See "Specifications of Leading Gars" for users, page 5^ 



*CXX)LING: Water Cooling. Circulating Pumps. Radiators. 
Fan. Water Thermostat. Radiator Damper. Air Cooling. 
Cause of Trouble in the Circulating System. Cleaning 
Radiator. Stopping Leaks. Non-Freezing Solution. Heat- 
ing a Car. 

If no provision is made for cooling the 
cylinder of a gasoline engine, the intense 
heat of the explosions would heat it to a 
point that would cause the lubricating oil 
to bum, and become useless. At the same 
time, the cylinder must not be kept too 
cool, for that would prevent development 
of full power; the cylinder must therefore 
be permitted to get as hot as is possible 
without burning the lubricating oil. About 
170 degrees Fahr. or below the boiling 
point, appears to give the best results — see 
page 188, fig. 9. 

The cylinder may be cooled either by 
water or air, and while the greater number 
of iBgines are water cooled, air cooling, 
however, has been developed to a point 
where successful results are attained. 

The water cooling system consists of 
jackets (see fig. 6, page 188), around the 
part of the cylinder that is to be cooled, 
through which water may flow; a radiator or 
cooler for cooling the heated water; and 
some method of keeping the water in circula- 
tion, together with the necessary connec- 
tions (see charts 94 and 95). The Jackets 
are usuaUy cast in one piece with the cyl- 
inder, although in some cases they were 
formerly made by forming sheet copper 
aronnd the eyluider to form passages 
through which the water would circulate. 
When heated, the water passes to the radia- 
tor, where the rush of air to which it is 
exposed absorbs the heat, cooling the water. 

Thermo-Ssrphon Water 
The thermo-syphon circulates the water, 
because when water is heated, it rises. The 
connections are the same as for the force 
system, except there is no pump, and the 
connection from the water jacket outlet to 
the top of the radiator slants upward. It 
is more necessary to have clear passages for 
the thermo-syphon system than for th^ 
force system, because the pump, in the force 


To maintain the cylinders at a workable 
temperature, a quantity of water is carried 
in a supply tank or radiator, from which it 
is caused to circulate continuously through 
the jacket of the engine cylinder by a small 
pump driven direct from one of the cam 
shafts or by the thermo-syphon principle. 
The heated water from the cylinder returns 
back to the tank on radiator and then passes 
through a series of thin copper tubes. The 
object is to dissipate as much as possible, 
the heat absorbed by the water by exposing 
it to a large cooling surface of metal. 

The radiator system is always fixed In 
the forward part of the car, to obtain the 
full benefit of the draught of air. The same 
water is used over and over again so that it 
is only necessary to replace the loss caused 
by evaporation and leaJcage. 

It is nsnal with radiator systems to have 
a rotary fan to assist in inducing a dranght 
of cold air through the radiators and ac- 
celerating the cooling when the car is mov- 
ing slowly, as in hill-climbing or slow 
running in traffic. The fan is £'iven from 
the engine shaft by a belt or gear and fixed 
back of the radiator. (Fig. 6, chart '95.) 
The alternative method, which avoids the 
use of a separate fan, is provided by fan- 
van ed arms in the fiy wheel. (See fig. 3, 
chart 94.) 

The two systems of dxculation are the 
** thermo-syphon" system and the "force*' 
system.* ♦ 

Circulation System. 

system, will force the water past an ob- 
struction that would stop the fiow of water 
that moves only because of its heat. 

Height of radiator — Thermo-Syphon syitem*— 
mutt be higher and lower than the extreme top 
and bottom of the water jacket. (See flg. 6. chart 

Height of water — Thermo-Syphon system — to 
properly circulate, water ihonld be kept at loTel 
above top inlet of radiator. Below this point cir- 
culation ceaaet and water boilt. 

Force Water Circulation System. 

In the force system, the engine drives a 
pomp which keeps the water in constant 
eirenlntion, as shown in fig. 4, chart 94 
and flg. 7, chart 95. The pump forces the 
water from bottom of radiator to the inlet 
at the bottom of the water jacket, through 

which it fiows to the outlet at the top, 
whence it goes to the top of the radiator, 
fiows through the radiator to the bottom. 
As it passes through the radiator tubes it is 
cooled. After passing through in this man- 
ner it is again drawn through the pump. 

*By referring to page 543. "Speciflcationt of Leading Oart" the cooling iyitems of leading cars, is 

**Levir prleed ears show a tendency to nse the thermotyphon system whereas higher priced ears the 
pamu or foriMMl efrmlatioii. 



♦♦Olrciilatiiig PimipB. 

Prmctically all water circulatixig pumps are 
dzlT«B by a gear on tlie crank shaft or cam diaft, 
90 that the motion is positive, and without 
■lipping. All forced circulating systems must 
use a circulating pump. 

There are three types of circulating pumps* 
in general use, the "gear type," the ''een- 
trifugal type" and the "rotary type" (see page 


Purpose of a radiator is to keep the water, 
which circulates around the water jacket of 
cylinders, below the boiling point. 

The location of radiator is usually in front 
of the engine where it will come in contact with 
the air. The air passes between the tubes or fins 
on a tubular type of radiator and through the 
ecllfl of a cellular type (see page 190). A fan is 
Bsually placed directly behind the radiator, 
which is operated from a pulley on crankshaft 
of engine, for the purpose of drawing a large 
quantity of air through the radiator, thus &• 
creasing the cooling capacity. 

Canstmction of a radiator. There is a reser- 
Toir or tank placed at the top and one at the 
bottom, as shown in fig. 7, page 188. Between 
these two tanks, the tubes or cells are connected*. 
A pipe connection is made with top and bottom 
tank from engine, as shown in fig. 7, page 188. 
When engine is running, the hot water passes 
to top tank, thence downword through the radia- 
tor tubes (if a tubular type), or around the 
eeDs, (if a cellular type), and is thus cooled. 
The cooled water then passes into lower part 
of engine from lower tank of radiator — see fig. 
7, page 188. 

Radiators must he used with either the 
"foreed-clrcnlating" system, using a pump or 
vtfh tba "thermo-syphon" system, which does 
not nee a pump— -see page 185. 

Types of radiators: There are two types in 
general use, the "tubular" and the "cellular 
or honey-comb. * * 

The tubular type consists of vertical tubes 
placed between upper and lower radiator tank. 
&e water passes downward through all of the 
tubes. If one tube becomes clogged, then all of 
the water must pass through the other tubes. 
Each tube is a seperate path through the radia- 
tor. See page 190. 

The cellular radiator consists of tubes or 
cells placed horizontally, through which the aii 
passes and the water flows downward around 
these cells or tubes. See page 190. 

The honey-comb type radiator was a term 
originally applied to a cellular type of radiator, 
due to its likeness to a honey-comb, but now 
that tubular type radiators can be constructed 
to have the appearance of a cellular radiator, 
the term could also be applied to the tubular 

Early Tjrpe of Badlator. 
The early t3rpe of radiator fig. 8, consisted of 
a corrugated copper tank, with horizontal tubes 

running length- 
wise of tank. A 
tank was placed on 
each side of body 
connected with 
water jacket of en- 
gine. A circulating 
pump was used to 
circulate the 
water. Modern 
constructions i^e 
shown on page 190. 

Tn order to cool the water sufilciently, a 
tan^ driven by a belt, attached to a special 
bracket on engine, is shown in figs. 6 and 7, 
page 188. 

Fan adjustment: the belt can be tightened 
by raising the fan by an eccentric adjust- 
ment, or by bodily lifting the fan and its 
bearing and tightening a bolt holding it. 
The belt should be kept tight. Slack fan 


belt often causes overheating. Ball bearings are 
usually provided and they should be kept weU 
oiled — (this is quite often overlooked). 

The fan draws a current of air through the 
passages in the radiator (see fig. 9, chart 94), 
in addition to that driven through it due to the 
forward motion of the car. There are two types 
of fans in general use; the 4 blade and 2 blade 
— see chart 97. 

Water Temperature Regulation. 

The temperature of the water circulating 
around the water jackets should be about 170° 
to 180*, at which temperature gasoline engines 
operate at maximum efficiency. If over this tem- 
perature or as high as 212*, the water will boil 
and steam. If the temperature of the water is 
low, then the cold engine condenses a portion 
of the gasoline, which leaks past the piston 
riagi, dilutes and thins the lubricating oil, with 
result that engine is not properly lubricated 
sad furthermore raw, unvaporized gasoline pro- 
daces carbon deposit in cylinders. See also, page 
205 and 155. 

I-Tbere are three methods employed to heat 
a cold engine: (1) to close the front of radiator, 
to prevent cold air being drawn through. Sudi 
an arrangement is shown in fig. 10, page 188, and 
is termed a radiator shutter; (2) by restricting 
the water circulation. Such a device is known 
as a water thermostat or syphon and is explain- 
ed on page 130, fig. 2 and page 860; (3) by heat- 
ing the intake manifold, as explained on pages 
155 and 157. 

Temperature indicator— see fig. 9, page 188. 
A condenser, to prevent loss of alcohol when 
used as a non-freezing liquid, see page 730. 

*CAltod tke *'Cor«", see iM^e 715 and 780 for meaning of "core**. 
**Bm foetaoU bottom i>age 185. fA new principal developed hy the Packard Co., is explained on page 855. 

Tig, 7. ThiB illustration sbows how the pump 
ahftft on the forced WAt«r circuUtliig syttem is 
ntuAJIy dTiv«u, »IftO tbo fan. "O** ar« gaiikitt 
coniiuctionii which mu8t ho kept tipht- — ustmUj 
made of nu nehestOB compaititioti. Also, shows thtt 
ptth of the water dreulatlon. 

Ailoto meter 


or Shutter 

Tig, 10. BadaoQ radiator damper 
or shatter. The vanes (A) like Fhut- 
tera on a window, open and close from 
seat by pull rod. When starting a cold 
engine Ahurrciri ar<? rlosyd. thoToby 
cuttiafE off lh« air circulation through 
radiator with result that the water be- 
comes heated quicker, whifh heats 
the engine and vaporites the gasoline. 
After '*raotormeter'* thowt prop^ 
•hutters aro opened, air circulation 

0. A tentperaAiure indleaior — the Boyce 

A very useful device for warning the drlfi 

when hia engine i» overheating, is called a "motomeleri 
This device is placed on the radiator cap. The fluid I 
the tube r«acheii different levels according to the 'tis 
perature. These flgures can be seen from the drirfri 
seat. If the level of the fluid reaches too hlffh a poinf 
the driver is warned to stop and locate the trouble be- 
fore serious trouble develops. In this instanc*. flrsi 
determine the different causes of ovtrheatinft and try 
first one. then the other until the troohle is found, IJ 
you think the trouble is in the lack of lubrtratioa, laefe 
of water or too much gasoline feeding at carburetor; 
examine each and remedy the trouble and watch tbi 
results. *A distance type moto-metar is also made, 
which can be placed separate from radiator and l| 
adapted for use on aeroplanes, motor boats, traelof 
eto (Bovce Moto M*>rer Co. Long Island City. N. * 


temperature, ,„,,„_. ^ „, ,„, „,, 

begins and temperature remains normaL 



Tig. 8. BAdtator cov«r over i 

cooling surface of the radisi 

during cold weather ts advUsU 

The roll In front on the radlat9t 

cor«r can be lowered or raisod 

during cold weather^ until ongini 

I warms up. Some merely tie a mttot 

l> of card board o^er the lower mal 

' of radUtor and keep it there di^ 

ing extreme cold weather. 

Hood cover: During cold we«|] 

the hood cover is advisable* ai 

OU^TOR lends to retain the boat under J 

covfiv hood. 

OHABT KO. 0fi — BxAOiple of a Tliermo Syphon Water Circulating System. Loeatidn of Pomp 
Force System. The Temperature Indicator (Moto meter). Tlie Radiator Damper or Shutter* 

*High altitudes, say 10.000 ft. above sea level, boiling point of water is resebetl about 14" below t}ffitit iodicated 
<ff iomtrument. *fiee page 921. 

Ii« object of cooliDg i« to remove the tPccoaB 

II from the cyllDders. Tliere mre only & few 
mn on Ibe markot in whicli thit it accomplished 
bf the «jiT direct, mritliatit the uso of wfttttr. 

Air (oolinc, however, i« coofined priacipalij to 
iBlU •DClA*s* >A motorcyclo au^ cyclo-car eaginuB, 
Air cootiDg ii oot auccessful with large cyliaderB, 
It ii necratary to ^Ive the cylinder a Large surface 
on whkh the air may act, and the usual method 
ta to make it with doep flangei projectiDg from 
l&t walla and Ifbad (aa ^ell aa the valve cham- 
b«n). which become heated, aa they are part of 
the eyiiader. (See fig. 6. chart 96.) 

When iQ motion, the current of air blowing 
iffainst the flangea drivea the heat away. 

Air cooled en^ea have amall cylinderi. aad 
muBt run at a high apaed to develop their full 

**Thfl Fr&nklln air cooled engine la about the 
only •uccesfiful engine for automobile pleasure cara 
«B|^loying the air cooled method. The six cylin- 
4fa% are 3H bore and 4 in. atroke, giving a 
formiila horaepower of 25.3. 


H|Ko *0 ^'^\^•^ ^i^ -i"^^^^^ 



^^^^^^^^R i^^^^^^4b ' 

Flf. 1 — Direct mtr cooling of the Franklin 
Thf fly wheel ia the only movinf part of cool- 
ing system. 

Voriiual iteel flna are made integral with the 
individual cylinder castiug, by iiaviag the irOA 
poured around the sifipa of etecL Very light 
ttluminum jackets guide the air draught downward 
from the heada of the cyliitders, 

By referring to the illustration the path of the 
air ia ahown. ftrst through hood, thence over 
and down through the air jacketa. The air is then 
deflected downwarda and out through the fly wheel 

Koto the vanes in fly wheel which create a suc- 
tion equal to 2,200 cubic feet every 60 aeconda; 
a conlinuous How of air literally wiping the heat 
away. It ia statod that the heat on a Franklia 
engine is about 350' Fahr., see fig. 4, page 167 for 
Franklin exhaust heated iolot manifold. This 
beat ia ahut off after engine is warmed ufi. 

The Franklin at one time employed auxiliary ex- 
haust valves to assist in dispelling the heat of 
explosion from the cylinder as rapidly aa possible^ 
This method, however, has been diacontinued. 

A forced draught air cooling syatom (fi^. 7. 
hart 96), formerly used years ago on a prominent 
uake of car. With this system the circulation of 
Air was forced through jackets, placed around each 
cylinder, open at the bottom and top, being eon- 
'^I'cted to a pipe from a centrifugal air blower or 
fan. The forced air pa^iaed the radiator flanges, 
and out at the bottom. In some respects, this 
principle is similar to the Franklin, 

The dllTerent methods of air cooling are anmmed 
up fts follows: 

U) By having a large radiating surface by 
i(*ana of caai flan^ea or gills, inserted pins or 
abea. (2) By uaing extra large exhaust valves. 
>Q as to cool the combuntion space between power 
strokea. (3) By combining targe radiating atir- 
r»ces with low speeds in multiple-cyhoder engines. 
;4) By the use of auxiliary cxb:»ust porta, com- 
bined with surface radiation. US) By forced 
draught of air circulating through an air jacket 
around the cylinder. 

Water Cooling Trouble&p 

coupling J (7) lost pin from pump abaft 
ge^r; (8) loat pin from internal pump 
mecbanism; (9) pin holding pump shaft 
sheared oBT^ but shaft continues to revolve. 

Otlier causes for engine heating: A short - 
ago of lubricating oil or a poor grade; too 
rich a mixture with a retarded epark will 
cause overheating; the apark bears a lixed 
relation to the mixture, which ia beat 
learned by experience. The valves being 
set wrong will also cause heating; for in- 
Btance, if the exhaust valve does not open 
and close at the right time the heat or burnt 
gas will not be discharged properly. Pre* 
ignition, want of compression, old oil being 
used too long; (cheap oils are false economy 
and only the best grade should be used). 
Improper driving will produce heatingi 
particularly in hilly districts, by hanging 
on to the third or fourth speeds when as- 
cending incMnes and so causing the engine 
to labor, and running on retarded spark. 

In some engines an inclination to over- 
beat gradually develops as the car gets 
older, and appears to defy all eflforts to 
remedy by means of carburetion or igni- 

This may be due to the dogging of the 
cooling system with incrustation or deposit 
in the walU of cylinder jackets and water 
system generally. 

I^Aiao «M Index for '*apark control and overheating and page IBS."' **Se6 index for "FratikUn 

Holmea Automobile Go., Canton. O., are alao cnanufacturera of an air cooled car with many 
* festttrea. 

^DTerheatlng : Assuming that the design 
and the construction of the engine, includ- 
ing all features of the cooling system^ are 
correct, then, outside of leaks, InBUfficient 
water and bursting of the water jackets 
ttijm freezing^ overheating is tlie final re- 
mit of all troubles from the cooling system, 
and overheating is due to either or all of 
tbMe aecondary troubles which may in turn 
originate from a number of primary causes. 

Secondary caoaes: First, the circulation 
of the water through the system; second, 
the conductivity of the heat through the 
walls of the cylinders or radiator tubes; 
third, the passage of air through the radia- 
tor and around the cylinders. 

Primary causes of overheating in botb 
theriDO and forced circulation: (1) Insuf- 
ficient water supply in radiator; (2) con- 
stricted boles in gasket where pipe connects 
to cylinders and on pump; (3) frayed hose 
eonnection; (4) incrustations or lime de- 
posits on walla of cylinders or radiator 
lubes; (5) mud between fins or cells of 
radiator; (6) water frozen at bottom part 
of radiator. 

Overheating causes in forced circula- 
tion: (1) Broken fan belt; (2) fan belt 
too loose; (3) tight fan belt bearing; (4) 
improperly bent fan blades; (5) broken 
pomp shaft; (€) lost pin from pump shaft 


Tubular Eadiatora* 

FurpOM of H nidiiitor. lee i»«ffe 107 ftad flf. 7, 
pufe 18B. •bowing how the w&ter «trcul»t«ft. 

Tli«Ti AT« two tn>«i of rftdUtor core* In genet*! 
thp "tubulur** find tho •'ciolhiUr"*. 

The tubulAT type of ruUator need In 1901} mad 
1901. U Ahown in fip. 18. The tubes were pUeed 
hoHzonUlly in he»dj (H). Ortmped flni (F) were 
plftced on the tubee. The »difttor was luipeaded 
under front of car by itudB (8). A pump circu- 
Uti^d llko water. 

The vertical tatml&r type with "iplrar' flni 
(F), fig'. 5, was the next t^rpe introduaed. These 
tubes were placed between an upper and lower 
tank, per fif. 7. pase 188. This type is sttU in use, 
princripally on traeki. 

Tlie veirtlcal tabnlmT type with *'flAt" ftni, ftf, 
5A, was the oeitt type iotroducod, the idea beins 
to have it reeecnble the eelluLsr radiator which at 
that time was introdaced on the Mercedes c»r. A 
tubular radiator made up with flat flna is ihown In 
lis. 1. 

F g. 5-B 

Fif. 6-C 

VtflAtloas of coDitrmctlon of the tubalftr type 
radiator are ihown in flc:s. SB, 5G, 5D« Koto the 
appOArance ii aimitar to the cellular typo, but the 
water flows through the tabes, whereias with a 
eellutar radtat«r the water flows enrand the tubes, 

^Cellular Type BadUtors. 

The original cellular type wae the Mercedes {fix, 
4). It cotiftiited of four or five tbousuod %" 
•guare copper tubes 4*^ lonjc oewted horizontally 
together, being seperatod from each other by wires 
•rr&nged to run between the rowi of tubes in 
both directions. The blocks eo iB«de ware eUmped 
togf^thor, and dinped in a betb of solder, both front 
and hack, by which means a apace Vs* thick was 
left on e»eh side of every tube. The blocks (divid- 
ed kntu ftoetiouB siwiUr \o fijr. 12) ^ht^n marie, 
were assembled with top and bnottom taok of radia- 
tor, and water was forced to pass in between the 
ttibes, the air being allowed to trarel through the 
Inside of the tubes. A rery largo radiating sur^ 
face was thnu obtained, and it would be hard to 
coucfllve of any arraoKumeut offering a larger radi- 
ating capacity for a»y given sixo radiator. 

T^ - --r rsdlator Is a ^ry expenslTo type to 
rHff»re. in thi» roimlry wht<iT«* large 
)e<iulred this construe i ton was guickly 
modiDPti i4i make Uie prodnetfon cthaapnr. 

Til* rXikT trtie oellalar type radiator is similar 
to the Mareedas. It is formed in fonr divisions 
indicated by horisontal 
lines. Where these lines 
cross there are open 
borisontal passages 
through which the water 
may flow from one side 
to the other. Thus a 
section can be remoTod 
and repaired seperately. 

Fig. 12 

Fig. 4 

Some of the modlflcatlons employed are shown in 
flga, 4A, 4B, Note in 4A, the tubes are expanded 
at the ends thus eliminating the wires. The Mayo 

f^. 4 A 

Fig. 4-fi 

is constructed in a similar manner with the water 
passage to the sides of tubes. The Fodders, tig. 
4B« the hexagon tubes can be romored and replaced. 
Tlie Harrison hexagon cellular is shown to the 
right, Betweem every other row of cells there 
it a water passage .08* thick. 

Fig. 8 

Fig. S. Front aad ilda ylev of a popular type 
radiator showing overflow pipe, upper and lower 
tank and connections. 

Fig. 9. Bzteaslon or syphon tank (t), used on 
many thermo-syphoo systems to give greater body 
of water and to absorb st«am and to maintain a 
constant level. A desirable feature on all radiators. 

Air OooUag Methods. 

Fig, 6. An air cooled cylinder, with radiating 
flangea. While la motion the air current carries 
off neat deflected from flanges. 

FIf. 7. A forced draught air eooHng method. 
See page 1^0 for a atmtlar method. 

Fig 6 

Fig. 7 

W KO. 9*— Typee of BmdlatOra. A^ OoollUg Methods see page ISg for radiator dampvr or shutter 
ealled a honey*comh typo» hut those are tubular constructions which resemble the eellnlar, for laai 



To ditafBint if tk« boUlnf !■ dne to itop. 
of elicBlattoii. foel of radimtor; it should bo 
•Ufht^ hottor at the top than at tho bottom, but 
if olonod thoro will hn a oronouncod difference in 

tWatar Boiling. 

Wotor boils «t 212 dogrooa Fahronhoit at atmoa- 
jglkmic p r o Mn ro. For thii reaeon the cooling lyi- 
tom of an automobile ia ao doeignod that the 
wator ia at tho temperature of about 170 to 200 
degreco under aTerage running conditions. 

This leaves quite a margin before the boiling 
pointy ia ' reaehed. _ Whan cUmbing a hill witli a 

apark tho ongino naturally 
and for thia reaaon the margin is left 
although aa a matter of fact the engine would run 
at a higher efPieiency if the temperature of the 
cooling wator could run higher. If the oylindera 
are kept too cool, it means that too much heat is 
boing withdrawn from the ozplosions. On the 
other hand, if permitted to become too hot, power 
ia lost through: — (a) the entering casea being un- 
duly rarifled or prematurely expanded, and there- 
by containing less combustible material per toI- 

MlBcellaneouB Oooling Tronbles. 

Wator: In loealitiea where pure water is not 
oaaily obtained it ia well to strain the water 
through muslin. Soft water is better than hard 
water, because the latter ia apt to depoait a aeale 
on the walls of the radiator. The beat water to 
uao ia rain water. 

ume; (b) friction due to tho thinning of tho oil. 
and probable binding or aoiaing of the piaton or 
bearinga. Thoroforo the boat wator tomporafcuo 
to manitalii is about 170 degrees, (see flg. 9, 
page 188.) 

Badlfttor Damper. 

Improvements In wator circulation aro ahiitt«n» 
aa par flg. 10, page 188. A very efficient heat 
conserring device. Engineers saw tho futility of 
putting gasoline into an engine to get heat and 
at the same time permitting great drafts of eold 
air to be drawn through the radiator to drive 
away the heat. Therefore the shutter waa doviaed 
to retain the heat, especially on atarting during 
cold weather. 

ttWater Thermostat. 

In addition to the radiator shutters, we have 
the heat "thermoatatically" controlled, which 
is another great advance to conserve engine heat. 
See flg. 2, page 130. In addition to theae devieea, 
warming devieea have been invented to deflect the 
heat from the exhaust manifold into the air 
chambers of the carburetion, as per pagea 167 
and 159. 

It ia very hard to tell whether water is hard 
or aoft, but the following may be used with suc- 
eeoa: Take a quantity of water in the handa and 
go through the motion of waahing. If it ia diffi- 
cult to rub the handa together the water is hard. 
Ordinary city water ia generally hard to some 
extent, but is not aa bad as that which is found 
In atreama. Bain water is very soft and for that 
ia desirable for automobile use. 

t0oo pago 780, 

It is a good plan to drain the wator tram the 
radiator about once a month and refill with oloaa 
pure water (soft water, if poaaible), opening tho 
drain cock and continuing to pour water in after 
the system fills in order to flush it out thoroughly 
letting all accumulated dirt, etc., run out. Aa 
effective way to do this is to keep on fllling tho 
radiator while the water eontinuea to run out 
below; when the water begins to look clear, atop. 
Olose the drain cock after you are aatisfled that 
the system is thoroughly clean. Oil must not bo 
aUowod to get into the cooling system, for it in- 
terferes with radiation. 

Oloaning a muddy radiator: If the air apaeea 
of the radiator become clogged with mud, after 
driving over dirty roada, do not attempt to re- 
move the mud with a screwdriver, wire, or other 
metal instrument. Instead, soften the mud with 
water. The best way is to wash the radiator by 
flushing a stream of water from a hoae through 
it from the rear. In doing thia. take care not 
to let water get into the magneto, which is apt 
to be short-circuited in that way. 

••Leaky Radiators. 

Leaks in the radiator aro ofton hard to reaoh. 
They are detected by the steam arising from the 
water that flows through the leak and down the 
outside of the radiator. The great facility with 
which the cooling water will boil after the radia- 
tor has been refilled is another clue which, al- 
though it is common to all leaks in the aystemi, 
will lead the operator to the point at which it 

Testing for leaks: see pages 194 and 716. 

The act of acouring out the drcnlatlon systoa 
with a strong alkali, such aa soda, will sometimes 
tend to seal up any small leaks, and it might 
also be effective for a slight crack in a water 
jacket as the soda, coming in contact with the 
iron, would form an insoluble filling and prove 
even better than rusting up the crack. 

Tho atandard honeycomb radiator ia somewhat 
prone to those leaks; the metal is so thin and 
the joints so numerous, and it is not always pos- 
sible to have a leak soldered up at the required 
time. In this case recourse can be had to a small 
useful accessory known as a *'leak preventer." It 
consists of a couple of small plates or washers 
with a piece of sheet rubber fixed on; these plates 
have hooks so that a spiral spring can be fixed 
on to draw them together. The spring is threaded 
through the aperture at the leaky cell, the plates 
hooked on. and thus held firmly up against it. 
Most accessory houses keep them, and if the car 
has a honeycomb radiator it pays to carry aev- 
eral of these devices. The construction of this 
type of radiator lends itself to a repair of this 
kind, but leaks in other forms of radiators, when 
they occur on the road, are rather troublesome. 
Even soldering them is by no means an easy job, 
there being surh a larf^e mans of motal that the 
solder cools as noon an it totirhes it. 
ttSea also psge 860. JWatcr heats quicker at hiRh sltitudes, «i»t v&ce 582. 
or drips aboat the cooling system can be traced to loose rubber hose. 

Isaka 1b tho wat« dreolatliig systom can be stopped by the use of p*" ^'~"" made for 

a oa foot note page 715. Une nmuulacturer states that ordinary ' with thr 

wdl stop a slight leak. The writer has never tried this. 

Many automobiliata have a rain catcher on the 
roofa of thair garagaa. while othera depend on 
tho old-faahioned raw-barrel. The water should 
bo filtered firat. however, if it is taken from the 
roof, aa it ia apt to contain impurities. But even 
with fairly soft water the monthly use of a 
soda solunon will prevent harm (this applies 
only in districts where the water is unusually 

Tho pump requirea no attention, other than to 
aoo that it doea not become choked by using dirty 
water. There is a "packing nut" on the shaft, 
which, if the pump ahould ever leak around the 
shaft entrance, ahould be repacked. This can 
very eaaily be done by turning off the packing 
ant, removing the old packing and rewinding the 
ahaft with a few inchea of "well graphited pack- 
ing" and tightening up the packing nut. The 
packing should be wound on in the same direc- 
tion aa you turn the nut to tighten it. 

Tho fan requirea no particular attention, ex- 
oopt oiling. Sometimes the bolt gots loose and 
eaoaoa the fan to slip and not to turn as rapidly 
as it should, causing overheating of engine. If 
this happena, loosen the nut which holds the ec- 
oontrie arm of the fan, raiae the arm slightly and 
retighten the nut. This will tighten the belt. 
Note — This nut froouently has a left hand thread. 
Don't tighten too tight aa you are liable to crack 
tho fan aupport. (see page 788.) 

fOloawIng radiator: A good way is to dissolve 
a half pound of lye in about five gallona of water. 
Strain through a cloth and put in the radiator. 
Bob the engine for five minutes, then draw off the 
oloaning mixture. Fill with clean water and run 
tto engine again; remove the liquid once more. 
and Anally refill the cleaned cooling system. 
▲void the use of more powerful chemicals. Or- 
dinary baking soda can alao be used, by mixing 
)6 lb. to 4 nllons of water. It is best to dis- 
solvo the soda in warm water before pouring it 
into tho radiator, otherwise the oryatals drop to 
tho bottOB. If the cooling ayatem seems to be 
vary dirty as far aa seals goea, it would be very 
wlso to ma the soda aolutioa through it several 
in order that all of the acale will be re- 


ExA itlng pump 

Bhrnti and see if pin u 

^^ If th«t% ftre water pipes Instasd of % 
^ eutlnf ; use fheHsc or wbU« U»d on the 

f»tketi. Screw ap fktkets liffht, but 
aoi too tight and itrip the tHireads of 
etp ac«w. 

WA«n plielan watar boi« 
backi, put white lead an tb<? 
end of pipft. 

VtriMf* fcl^ iMltt «n oft*** f«lMltf 

Wlien pUeliiK WAtvr hMid 
caating back on top of cylinder 
use abellac or wbitt lead on the 

•An alt lock 

often occara in 

the top of an 

loTerted U 

beitd ia the 
jf^jgga^ ^^^^^ ^^^^^ 

^zr- ^-r- -=r:^:^ of aa enfina» 
which m e a n i 
that almost the whole flow of water has been itoppad 
al that point. No amount of presaure from the witer* 
can dlalodge the air, becaate ita only affaet will be to 
compraiB the air in the top of the bend. The remedy, 
ia either to relesae the itr nt the top» by puttiof in a 
pet eock, or else to empty the wat^r and earefally refllL 

Uae rain water for tbt radiator, if 
tber« ia a tot of lime in the wtter and it 
!• conttaotly clogfing up. See page 191, 

cleaning radiator/ 

if eoglne baata, or water boUa over, 
aaamine the fan belt, eee that it la tight 
and fan runt np to apatd. There la na- 
oally an ftdjaatmpnt for taking up ilack 
balta. A littla FuUera earth on a greaay 
bait, will make it grip if it alipa. 


A two-blade fan 
—called the pro- 
pallar typa. 

Make aore 

that apark- 
p 1 u g a are 
acrewed i n 
tight. L o a a 
of comprea- 
alon will re- 
anit, and miaa- 
ing, a natural 

HemtlJig tlie Oat. There are Tbree Heating Principles: 

fe r-r6^>^ "S- 

(1) hot water; (2) exhaust gas; (3) hot 
air* The two former mentioned are ex- 
plained in chart 98. 

The Briekley hot air heator takti the air from 
the fan through a funnel opening, and a flexible 
metal bote; drtvea it through a metal jacket 24 
to 30 inchea long, which corera the "piping hot" 
exhauat pipe, and warma it thoroughljr- Then 
drlTea it throngh a l^-inch opening in ibe floor 
of the tar. into a tubular regiaterp along th« back 
edge of the front teat; tending a eonttnuoua 
atream of heated air into the car. (Erfaautt gaaee 
not u»ed.) 

OHABT NO. 07— Cooling Troubles and Bemedlea Blnstrated: Fam, Heating a Gar. 

"When filling radiator which it empty, open pet eock oa water pump for a moment to prcireat air pocket. 




Both^ pUn ii to carry m imall box of white 
of « tuiuble coniiBtdncy. If the water is not 
\ag iitrou|h quickly, m tempottirf repair can ba 
iBsde with thii, ^epeoieUy it m pi«€« of Upe can bj 
aDj ineaat be bound over the repair. It ii often pos- 
atbla to hamtner op or plug a lealcAfe iu a tftok or 

tfThe rubber hose and Its 
connections are often m 
source of leaking* When 
tbe boite it worn it will 
beeome rag:sed-loc»kine on 
tb» outiide. Tbe mbber which surrounds the fabric 
wili commence to have a torn appearance and the 
«»t«r wiil leep throorh the fabric. There are two 
wajs of TtmwflJif tble : one is renew the hose and 
thm other it to r«pair old hose. The first is the better 
aad more pennaaeot repair. In doing this a piece of 
ho^e of the eame thickness and length ha that now in 
place is secured. The etamps which hold tbe hose in 
place are removed. The new hose is slipped m place 
aad the clamps put over it and screwed np tightly, if 
tk«r are of sncfa a type that they are secured by a 
amaU holt. If not. the operator will do very well to 
abtala same. The cost will be small and they are 
e*ai)y remored, being far better for this work than 
srtre «r any similar contrivance. Paint atl threads of 
water pipes with white or red lead. 

Cylinder leaks t A slight leakage of water from tbe 

jacket into the cylinder may be caused by a crack* 
but more usually will be found to be simply a defect 
in the seating of pipe plug fitted in the heads of many - 

•A crack In cylinder — when on the inside, is difficult 
to locate. Its action may be of such a nature as tofl 
b« only operative when the engine is at full workings 
heat; due of course to the expansion. It is genemlly * 
accompanied by misflring and boiling. The former 
owing to leakage of water into the cylinder and the 
latter owing to tbe exploding gases (at a very high 
temperature), being forced into the water jacket. 

The best means of detection, is to fill radiator en- 
tirely to top of cap« nin the engine till hoU then stop 
it and turn it over by hand against the compression la 
each cylinder, if there Is a crack: bubbles will appear 
at the cap. So hj noting tbe compression of each 
cylinder, the defeciiVB one can be located. 

Blight I«aks inside of cylinder have been remedied 
by rusting if the hole is very small. See page 713, 
**ruBtiDg a hole in cylinder.'* 

QasoUne leaks: A temporary repair for a slight 
leak in a gasoline tank can be made by applying 
ordinary soap. Such a repair may last till the defee> 
tive part can be soldered. Leaks at gasoline taps can 
generally be cured by screwing up tbe nut securinf. 
the tap plug, or by grinding in the tap with crocuaj 
and oil. 

Gold Weather Precautions. 

In winter, a water cooled engine must be careftilly 
fmtrded against fteesing, for if the water freezes in 
aay part of the system it will cause the breakage of 
•ising or radiator, or crack a woter jacket. When the 
■DcSne is running, the water is kept warm, therefore 
mm danger: it is when engina ie stopped that eara 
b« taken. 

When learing the car for leTeral days, during cold 
w«ather. the safest plan is to drain tbe water out of 
all parts of the system, cocks being provided for the 
porpoae at the lowest point of the system, usually at 
lh« bottom of radiator. The engine should be run for 
• few minutes to make sure all the water has been re» 


fNon-Freeziiig Solutioii84 

1 Jiter from freerJnK" when it is not 

ii^gir out. either wood alcohol, denatured 

alcoL- „ . ™>*y 1j« mixed with the water. Tha 

aleob^'I miAlia«} u as follows: 

Wood A^tcohol And Water, 
10' abov* f«ro; 807c i^aier. 20% alcohol. 
S«ro; T6% water. 25% alcohol; sp. gr. .969. 
7" below rero; 70% water, 30% alcohol: sp. gr. .©08. 
7:1' ^low s«ro; 60% water, 4©% alcohol; sp. gr, .951, 
If denatsrad alcahol Is need, increase percentage in 
abare table by approximately 1&. 

Ftof sfTaporatlon — use 75% alcohol to 25% water— 
m» Ike at'-ohol evaporates quicker. This does not apply 
to boas by lesks or boiling over. 

▲ kydroiD0t«r can be used for mixing and mntnlain- 
eorract solnUon. by first testing the original and 
It up to a standard. Denatured nleohol Is 
dnd In preference to wood alcohol as the boil- 
ings jwitr.t i« ir»* hicher. 

01yc«Tln« ft&d Alcohol. 

IM tovtv Ikaa 6 btJow: 

lot hfW 

fwvt tl.aa 15 belt 



. . 10% 
, . 10% 

. . 15% 

. , 15% 

., 7e% 

, . 66% 

Where glycerine la usad only alcohol need be uBed.| 
for evaporation, which should be added occasionally* 
The glycerine does not evaporate with tho water. 4 
simple solution of alcohol, while it ts not injurious in 
any way, lowers the boiling point of the water. Conse- 
quenlly on warm days, with the car atandinsr and the 
engine running, the solution will tend to boil easily 
and evaporate. The boiling point of denatured alcohol 
Is about 10 degrees higher than that of wood alcohol. 

*^The use of glycerine raises the boiling point of 
the solution. It is more expensive than alcohni (a 
pound of glycerine costs 88 He. There are 8 lbs, to a 
gallon) and is Hlightly injurious to rubber. A com* 
bination Bolution of alcohol and glycerine in water 
is moat satisfactory but expentive. 

Thare ara thTe« grades of alcohol: denatured which 
U a disguised grain alcobot of 6rst still, (not suitable 
as a beverage). It sells for $1.05 per gallon and has 
a higher boiling point than wood alcohol. Wood 
alcohol sells for |1.60 per gallon and has a lower 
boiling point. The high proof or double still grain 
alcohol used as a beverage is too expensive. Therefore, 
denatured alcohol is cheaper and the proper thing 
to use. tt Alcohol bolls at 172* ♦ Therefore don't 
overheat engine. 

Oalclnm chloride or any alkaline solution, is in>^ 
jurious to metal parts. 

If calcium chloride is used, then the proportions 
are: rt*4 pounds to a gallon of water for lero weather, 
aud 4 Iba, for 17* below. In using calcium chloride 
it la the acid in It which attacks the metal. This can 
be neutralized by adding ammonia or soda ash until 
blue litmus paper no longer turns red when dipped Into 

If the cooling water shoitld freeze; tKe usual Indica- 
tion of A frozen radiator is steaming excessively. II 
would appear that tbe «teara or heat would thaw it 
out and start the circulation again* but such Is not 
tha ease. When tho water freezes don't run engine to 
try and start circulation. Find the nearest warm 
garage and, if possible, turn hot water onto the bottom 
of radiator until steaming ceases, as a radiator in thla 
instance usually freeies at the bottom first, (See bottom 
of page 78a,) 

In addition to uon-frettElng tolntiont it li alwayi 
w«l], when making a stop, to cover hood and radiator. 

Also draw In a full charge of gas by speeding np 
engine and opening throttle before stopping. 

In carbide gas lighting generators using the water 
drip, a suitable non-freexing solution is alcohol and^ 
water, same proportion (no gtyceriDe), 

■■ireexing point of gasoline, alchobol,*' etc. ••Price* not now correct. 
ly. Sold by all supply houses. Kerosene la not snltable for aon-froes^ 
_ ^ given ' J tfOn airplane engines, where hose connection is made to the pipe il is 

set a«ly eonfi«ct«d with a connector, but connection la taped and ahetlaced. ^B# tore that the radiator 
iam not IcAk and that hone connections are tight before putting in non-freezing soltition. 



Eadlator Leaks. 
Testing for leaks. It is hard at times 
to detect the exact spot at which a leak 
occurs in a radiator. The best plan is to 
remove the radiator from the car and plug 
op all but one opening, then run the tube of 
a tire pump through a cork and then place 
the cork in this last opening. 

Place radiator in a tub or box which will 
hold water and submerge tbe radiator as 

per illustration. Then pninp air into radiator. 
Bubbloa will issue from the point of leakage. 
The leaks should be marked and radiator re- 
moved from the water. 

The eext procedure Is to determine if 
the radiator is a tnbolar or cellular type, by 
^udying page 190. Then read pages 714, 
715 and 789 and proceed with the repair. 

Remember, when soldering parts of the 
radiator that the metal must be scrtipiously 
clean before the flux is applied or else the 
solder will not hold. 

After completing the soldering* file 
smootbly and then place radiator In the 
water and again test it with air pressure in 
order to see if the leak is properly repaired. 

Smftll 1e«j£J Are dealt witli oa psfti 191, 198 
Bnii 715. 

Painting a Radiator. 
It Is very difficult to paint a radiator 
quickly and thoroughly with a paint brushy 
and the usual plan« where a great deal of 
tbe work Is done, is to dip the radiator in a 
Iialnt solution. A very satisfactory job can, 
however, be quickly done with a spraying 
outfit. A very simple and home made device 
is here illustrated. 

It consists simply of a construction such 
as Is shown in fig. 4, in two sizes and designs, 
which comprises a can (D) for the paint, con* 
aisting of a mixture of lampblack and tur* 
pentine, a hollow cylindrical tin handle (B) 
attached to the can, an air pipe (A) passing 
through the handle and through can, as 

indicated by the dotted lines; and another 
similar pipe or tube extending downward at 
right angles from the one end of the horizon- 

Fl^. I —A hQine- 
m • il * %pt*Yft far 

f:S*r «ito« iixat nsL 

tal tube into and near to the bottom of the 
can, as is also indicated by dotted lines. This 
is merely an adaption of the principle em- 
ployed in most atomizers. 

FIff, 5— Staowisc 
^a* fke pmimt It 

(or (»cc pitgt SOS. lot 

When a stream of air is forced through 
the air tube (M and A) passing through the 
handle and diiected across the opening (0)^ 
at top of the vertical tube the fluid from 
the inside of the can is drawn up and spray- 
ed onto the radiator. It is best to tUt 
radiator when spraying, so solution will drain 

Heating a Car. 

There are three methods of heating a car 
as explained on page 192. 

Illuetrsllon sbowi th« ho% w»ter m«fttiod wbieh 
cao oalj^ be USftd where tbera U a forced or pump 
circulation syAtem. Connectiont are made with 
the circttlatinir ajritem at the top of rear cylioder 
and circulated throngh the heater, whence it reiurtit 
to the bottom of the radiator. 

The heater is made of rejnilar water pipe and 
the bousiof of aluminum or Ii|rhl eaat iron, Tha 
floor U cut away, allowing the sarface of th« 
heater to be fiuih with the floor. The top plate, 
made of alumitiQiii ia then placed OTer the heater 

Tli6 ttzhsmit method for heattug is to ntlllsa tlie 
exhaust gaata Instesd of water. la thit initance 
the pipe* would be connect cut with exhau-it jupe 
in«teA() of the water pipe. Only one side, the inlet 
would be connected end an outlet li provided for 
the emission of the guM. 

The hot air method ia ahown od page 192« 

OHABT NO. 98 — Testing a lisaky Eadlator (so*? also, pages 714, 715, 789). 
(lee also, pa^ca 194, 509, 736. 584). Hot Wat«r Heatli^ of Car. 

Painting a Badlstoi 



Ftg* 1. Som« of Uie earty m«tbo4i of «iigtiia tnbrlckllDii. There &ro four diftettjii iytttenu ibuwn on 
ihia esfise is order to elemrly explain eiicli lyitflm. Tti« if ft terns Are eaomernled uid deicribed below, 

E^lanatjon of tlio Four Engine Lubrication SyBt«ni&— Above. 
FfiBt: Wo will follow out tlio splash system ; wo will auaume oil le placed in erank case 
ynongli breather pipe. The icoops (O) on en/l af conDecting roda pick Dp tho oil from troughi 
(£), and splash it to the various parts. 

Fon^ feed, splaab and gravity. We will assume the splash system just do- 
■erilMd ia a part of thia system. Tho overflow passes to reservoir (V), it is then forced by 
pigmp (M) to a gravity feed reservoir placed pn top of engine. The passage ia then throogb 
Iko ditfereut pipes (S to L) to the bearings^ thence back to the troughs (E) and reservoir (V)* 
Tkii pystem would also be termed a circulating sy stem, as the oil is in cDntinual circulation. 

Third; Separate forced feed and splash^ The mechanically operated pump is driven by belt, 
ekain or bevel gears. There are several small pumps under the oil reservoir boi (N), In 
fact a pump for each feed; each separate feed la piped to the different parts to be lubricated. 
The oil paases through a sight glass (G). The oil then passes to bearings and falls to bot- 
tom of erank ease. The oil reaches a level or height in the crank case so that the connect- 
Snf rods give an additional lubrication by splash. The amount of oil fed ia regulated by 
drop% through the tight glaiseSr by the regulation of the screws (D), and depends upon the 
•ice of engine and speed* (Note — pipe (F4) is not connected with this system.) This would 
be t«rmed a non-eirculatiag system. 

Potiitli: The exhaust pTessure feed and splasli. This system consists of an air tight oil 
iMxik or reierroir (FT), A small pipe (PI) connects the tank with the exhaust pipe. A eheek 
valve permita the gas pTesaure to pass into tank but not to flow back^ 

The initial pressure is given to the tank by a small hand pump through pipe (P2)« Aftdf 
tai^nm ia atarted, the pressure from exhaust is sufficient to force the oil through pipe (P4} 
to iiglit feed glassesj thence to the various parts to be Inbricated^ — thence to crank case^ 

Tkia system, like the third system, requires oil to be fed by drops as it ie not pumped 
evM and used agiun and would be termed a non-cireulating system. 


Lataleatioii Systams. The above explains some of the original systen 
Tlie modArn systems are explained farther on. 



timet cut around tlie lower part of tbe pis- 
ton, and the oil BplasMng into this is car- 
ried upward and distributed on the cylinder 
wall and rings. Tbere are no oil trouglis 
in thia syatem. 

As tlie oU Is us€d, more must be added to 
tlie crank case to keep tke necessary level. 
This if done either by moans of (1) a hand 
pump connecting the crank case to an oil 
tank or (2) by an oil cup that drips a cer- 
tain amount of oil into the crank case every 
minute, or (3) by filling through a breather 

With the hand pump, the driver gives it 
a stroke or two every few miles, experience 
being his guide as to how often and bow 
njtich. This latter syBtem, however, is not 
mnch used on automobileB, but is exten* 
Bively used on motorcyelea. This system 
would be termed a non-circulating syateni. 

rif. 1. 

The objections to 
tlie splaah system 
are as follows; re- 
fer to fig, 1 — note 
the engine is in a 
level position. An 
long as the engine 
remains level the 
splash system gives 
fairly good satis* 
faction^ so long as 
tiie level of the oil is kept up to the lowest 
point of the connecting rod where it can be 
picked up and thrown to the upper part. 
If, however, the car Is in such a position 
the engine will be tilted, aa shown in fig. 2, 
then the oil goes to the rear cylinder. Tb© 
rear cylinder is over lubricated and the 
others are under lubricated. Even though 
a "balTle*' plate is placed as shown in fig. 
8, still there is one cylinder minus oU, 
Therefore some other means must be em- 
ployed so that all cylinders will receive 
their proper share of oU. 

Oil.rii9>it6 I won 

The Ford temi-cireulmtiair ■7stem< 

Splash System— semi circulating. 
One method of overcoming this latter | 
mentioned objection is to provide troughs 
(O) under each connecting rod, which is 
shown in the cut of Ford engine. The 
troughs retain the oil, even though engine ia 
at an incline. The next method is to keep { 
the oil at a constant level in the troughs. 
This is accomplished by some means of cir- 
culating tbe oil, In this instance the con- 
stant level of oil is maintained by the action 
of the fly wheel. 

The fly wheel 
throws the oil to 
the top of the trans- 
mission case where 
part of the oil ia 
caught by tube 
*'T" and fed by 
gravity to the cam 
gears. The overflow 
coming back tends 
to keep the troughs 
(0) filled with oU. 
This system would be termed a semi-circu- 
lating system (used on the Ford engine). 

♦♦Splasli System^eirculating. 
This system could be termed a "circu- 
lating splash system'^ also a ''pump over" 
syatem and is the true constant leirel, cir- 
culating splash system because the oO 
trougbs are kept at a constant level by a 
pump. Could also be termed a ** force feed 
and splaah" syatem. 

The operation of a ''circulating^' or 
*'pump over*' oiling system is shown in 
fig. 6; the main oil supply is contained in 
the reservoir (R), from which it ia drawn 
by the pump (M) and forced through the 
pipes or leads (L) to the main crank shaft 
bearings (G). 

The overflow from these 
bearings is thrown by cen- 
trifugal force against the 
walls of the crank case 
and cylinders and, as it 
runs down, is collected by 
inclined channels (N) 
which conduct it to 

For lubrication of the 
connecting rod bearings, 
scoops (8) are fitted to 
the lower ends of the con- 
Fig, «. necting rods, which dip 
into the oil contained in the troughs and 
scoop it up Into the crank pin bearings at 
the lower ends, and through tubes (B) run- 
ning up the rods to the piston -pin bearings. 
Overflow pipes (P) are provided in the 
trough so that the excess oil can return to 
the reservoir (E). 

The pump (M) Is usually a gear type of 
pump, operated by bevel or spiral g^ara 
and vertical shaft from the cam shaft 0. 
On many engines the pump ia a plunger 
type operated by a cam from the cam shaft. 



*A bresthar for as engine (ms Studebnker. p»f« 71), it ft pipe openias conniietad with cr«zLk 
tmme, vb#rt oil it poored into crank c*t«. Tbt opening ii cloied by ft cftp wbich doei tiot flt tight, 
bat allows the &ir to «nter, iind at th» t^&tiip. lime proventH oil from working out. **Th<l depth of 
oil In oil-pan of a.n eagiiia using tbo spla«1i i/stem ahonld bo juat enoafb so that tho Hpluah will 
dlatribttto the oil. 


Fl^s. 3. 1, 2: MeUiod of drctilAtlDQ of Uie Hndsoti 
Sapor six "drcuUtliig- spUah aystein:*' The ml i» 
Ukcn from the presacd iteel reservoir at (A), itrainiiii:' 
All of it through a. Alter or metBl «cre«ii of tne meih. 

The oil ii fed directly into the front compirtmeot eon* 
Uiniof the tiroln|r geara ^t (T> aod their hearinft Aod 
flowm from thia ioto the nrst oil trough imtiicdi»tel]r oodor No. 1 
cylinder (tee fig, 8), The lorgo iplather on the end of the coonecti&g 
rod practically empties the oil trough at every revolution, throwing the 
oil into auitahle channels or guttera on the tidn of the retexvoir and 
crank caae. 

The upper gutters tB^d the main bparinga in a conlinuoui itream, 
lower gutter feedi the oil directly into No. 2 oil trough. 

The iplafth frora No. 2 oil trouf^h fecdn No. 3, and so on until No. 6 
oil trough it reached, at which time the oil fiowi back Into the reeervotr. 

The eonnccting rod dipper ii aufficiently effective to pertait a very 
bigh level being maintained, thus insuring lubrication on all grades with- 
onl excesaive oil conaumption. The two center bearings *re fed by 
two trougha each. 

The front bearing la fed from the tuning geara aod one trough, »nd Ihe r©ar bearings is fed by two largo 
trougha. It if apparent Chat all oil which eoteri At the front end must circutAte throogn the Tarioui 
troughs to the reservoir again (ae« page 200). 

riff. 4: M«th. 

od of elxeul*- 
tlon of tlio 
Kijxg "Foieo 
r e« d Syi- 
torn:" Thero 
are no trougha 
or splash witb 
this ffyttem. 

Oil poured in- 
to the filler 
tube, flows 
down into the 
oil pan, flUiiig 
it up to « 
height indi- 
cated by the 
oil level gauge 
on right-hand 
side in tester 
of engine. 
From tbo PAH 
o T reaerroir 
the oil Iff 
drawn up 

through the oil punsp. which is driven by a vertical shaft from spiral gears on the camshaft. The oil pump 
Itself Is aurrounded by fitie 8cre<;n so that all oil entering the system is thoroughly strained to remove the 
dktt or lint thai might stop up the oil ducts and cause damage. The illustration shows the principle of the 
system, and by following the Arrows the oil can be traced from the reservoir to the various pArta of the eng ine. 
TliA geAT pump at the extrema bottom of reaervoir draws the oil through the tcreon which surrowidA 
it And foreea it into a dl>M1>tiilng pipe running the entire k-ngth of the craukcase. From Ihla pipe Uio 
lubricant Is forced to each of Ihe three crAnkshaft main bearings. 

Prom the main bearings the oil is forced through holes in the crankshaft to the connecting rod 
leAringa. Since, at every revolution of the erankahaft, these holes register with the leada from the dis- 
tributing pipe, an exceta of oil is forced to the connecting rods, where it is drawn off in fine drops or 
miei onto cylinder walls, A part of this spray, is also utilised for lubricating camahAft valvee, UppotA, 
PrtncfplA of AdJOBtmont of the **Bpriag And 1>aI1" taIto; the ball is plAcod in the pAth ol oil liao 
with A spring tension behind it. When pressure of oil circolatioo is reached, to which spring tontloD it 
Adjusted, the bail is forced open And oil overflows past hole; in this instance, to the eluiin sprocket. I& 
other words it is merely a "relief valve." (see page 300.) 

Tbe * * Oirciilft ting 

CHABT NO» 99A— Example of Two Modem Engine Iiuhrication Systems: 

Spl&sb** (Hudson ms example) and the '* Force Feed'' System (King). 

•Note the "eccentric" moYemeut of cam for udju#tinc the pTP««ure on the Hadson, and the 'llftlf ASd Wprtng 

ValVA" on the King. Also see pege 594. for Adjusting Hudson Oiling System- 



Force Feed System. 
Oil is forced by pressnre ftom o11-imui by 
a pump, to crank-shaft bearings, then 
through drilled ^oles in crank-pixis, per 
King system, page 198. Oil is not forced 
to piston-pin, pisUm and cylinder, but these 
and other parts are supplied hy oil thrown 
from the crank-pin bearings. The connect- 
ing rods do not dip. 

Full Force Feed System. 
Oil is forced by pressnre from oil-pan by 
a pump, to crank-shaft bearings, then 
through drilled holes in crank-pins, per flg. 
4, this page. Oil is also forced to connect- 
ing rod upper part, or piston-pin through 
ehannels or pipes, thence out piston-pin 
to wall of cylinder. Thus the dilference be- 
tween the "force" and "full force" sys- 
tem. The connecting rods do not dip. 

Note the dotted lines showing the path 
of the oil. (A) is the oil reservoir. (B), 

? Oil Pimip and Oil 

The Oi)^Fump. 
There are two types of oil circulating 
pumps in general use. The gear type, fig. 
1 and the plunger or piston type, fig. 2. 

|o«nin ^^ g^3, ^jyp^ (gg 

1) can be operated 
by chain, but is usu- 
ally operated by a 
shaft, through bevel 
or spiral gears, as per 
fig. 6, page 197. 

The plungtr type 
(fig. 2) is usuaUy 
driven from the cam 
shaft, by an eccen- 
tric, and on marine 
engines instead of 
utilizing the cam 
shaft, the pump is 
sometimes driven 
from the crank shaft, 
fig. 4. 

The adjnstnient of thii 

piston or gear type of pump, (G), eccen- 
tric or gear for operating pump. (O), 
(^auge placed on dash to indicate the pres- 
sure, (F), cheek valve, (D) is a strainer. 

Fif. 4 — ^Diapmm of • "fall force feed" system. 

This would be termed a true "full force 
feed" engine lubrication system. 

type pump U made by 
icrewmf the plunger-rod 
(0) in— (this shortens 

the stroke); or out — 

which leojrtheni the 

stroke). This lengthen- 

^ ^ ^ ^ « ing or shortening of the 

e^oke, hat the effect of regalating the flow of oil. 

The longer the stroke, the more oil flows and vice 

Fig. 2. 

A modlflcatlon of this type is shown in 
flg. 1, page 198 — note the plunger is 
shorter and is operated by a cam or eccen- 
tric movement. The cam forces the plunger 
in and a spring forces it out again, thus 
ereating a suction effect which draws the 
oil from the lower reservoir. 

Oil Pressure and Gauge. 

This is a gauge placed 
on the dash board (see 
page 188), which shows 
the oil pressure. The 
normal on the Pack- 
ard is 20 to 30 lbs. 
at 1000 r. p. m., engine 
hot. On the King, 15 
to 20, on the Pierce- 
Arrow, 3 to 4 lbs. at 
lowest speed — to 36 

Pressure Gauge. 

lbs. at highest speed (50 m. p. h.); Cadillac, 
5 to 7 lbs. when idling. 

If the indicator needle on gauge drops to 
sero, it indicates oil level is low or for 
some reason oil is not circulating. In cold 
weather it may be an indication, that the 
cold test of the oil you are using is not 
sufficiently low and that the oil has con- 
gealed to a point where the pump cannot 
draw it from the oil pan. Do not under 
any consideration continue to run the eor- 
gine if the hand on the cowl board vibrates 
or returns to zero or if it remains at zero 
after starting the engine. 

The amount of pressure varies with the 
speed, temperature and viscosity or thick- 
ness of oiL 

When the engine is cold, the pressure will 
be higher until the oil thins down. An ex- 
cessive, pressure on the gauge may also in- 
dicate the clogging of the system. 

In other words, maximum pressures will be 
indicated at given speeds when the engine is cold 
and the oil is fresh: minimum pressures^ when 
the engine is hot ana the oil becomes thm. 

Practically all engine lubricating oils become 
less Tiscons from nse even under normal condi- 
tions. Running the engine too long with the 
"choker" control lever pulled back will cause 
the oil to be thinned more rapidly, due to the 
condensation of gasoline from the rich mixture. 
See page 205. 

Too high a pressure will cause abnormal 
oil consumption. This should be adjusted 
according to the pressure recommended by 
the manufacturers (see page 542). Always 
adjust when engine is hot. 

Regulation of Oil Pressure. 

There are two general methods; (1) by an 
"eccentric" movement as per fig. 1, chart 
9 9 A, and by the adjustment of a "spring 
and ball" valve as per fig. 4, chart 99 A 

If gauge does not show pressure: Make 
sure that the oil pan contains plenty of oil, 
as shown by oil level indicator. Should this 
show "full," remove priming plug on top 
of the pump and start engine. If oil flows 
from this, the pump is working and the 
trouble is with the gauge. 


FflBUilf tlio pump; In cue joa think thai Uie 

i^ttmp ii cloned it ii a pood pUn before taklni; 
I down to trj prrmins it with the lAme kind of 
oO IhAt 70a put in the cr»nk e&ie. To primft tb« 
pQXDp, remoTo the ping, poor m oil untiili it AlU, 
rtpUee the p!of end ttAii engine. It priminf 
iocs no food then it will he necftBearjr to clenn 
fft« pipes in order to find the obetructfon. It te 
al«d adTiftAble to occaaiooftlly clean the oil atraiQEr. 
When the pump ia taken down it must be 
primed with oil, after replacing 

fShonlir St any tlm« tbo oil gmnga ahow fnU 
prm§wni9 when runniiig at % alow apeed. foreign 
nutter hai become lodg^ed la jour dlitribntor 
pipe lAd 7011 will have to proccd ai followi: 

Take off oil pan, remove oil pump by removinf 
emp aerewa which are aaually acceeaible throofh 
th« holes in the clutch cone and flywheel. The 
diitiibuior pipe may then be drawn back throufb 
the openlnje: left by the pump, and it ahoold then 
be blown oat with air pretinre. 

If the ayatem ia a aplaah lyatcm aa well aa a 
forced circulating ayatem, it ia poaaibte to drire 
in, but be Bore there ia plenty of oil In pan. 

fSoinetlmea kilgh sange preAaure is due to eold 
weather and heavy congealed oiL If after engine 
ia wanned tip the preatura ia ezceaaive and the 
regulation does not vary it. then it can be attri- 
butad to clogged pipea« 

Example of Modem *'Clrculatiiig Spl&sli" System — See chart 9 9 A. 


A modem engine lubrication system com- 
bining tlie splash and pump circulating sys- 
tem ifl shown in illuBtration figs. 1, 2, 3 — 
use^j on the Hudson super six. 

DU pump; plunger type, mounted at front 
of eng^ine and driven by a vortical shaft 
from crankshaft 

Regulation of oil pressore is governed 
by the speed of engine. An ^'eccen- 
tric** (E) 18 connected with the carburetor 
throttle. Thie keepa the cam from operat- 
ing on the plunger; should the regulation be 
set so oil gauge registers 1 to 1^ degrees of 
pressure when engine ia running slowly. 
By this we mean at speeds from 10 to 20 
mileo an hour, (see also page €94.) 

Am the tbrottle is opened, the eccentric 
is turned away from the plunger so as to al- 
low it a greater amount of travel from the 
earn action. When the throttle is wide open, 

Example of a Modem ' * Force 

Tho principle of operation, is explained in 

lower illustration in chart 99A and the 

t«xt pertaining thereto refers to the King 


The pressure regulation which differs from 
the Hudson is explained below, 

Oil prMBure regulation 1 The pressure of 
the oil in this force f+*od system is controlled 
by a "iiprlng and ball^' valve located on the 
front rigbt hand side of the crankease. The 
valve is provided with an adjustment which 
should not be tampered with unlesB the pres* 
sure drops below i lbs. or raises above 20 
pounds^ when tho engiae is speeding up. 

To rogulate, loosen lock nut and turn pres- 
•ure regulating screw to the rlgbt to in- 
Urtait tat prossure, and to the left to de- 
CTOaM M «oo piigt* 198. 

the eccentric should be in such a positioja as 
to permit a full travel of the pump plunger. 
By this adjustment, the oil pressure shown 
OQ the gauge will gradually increase as the 
car speed increases. It should register 8 
to 4 degrees at 30 miles^ per hour. 

If gauge doea not show this amount as 
above, the pump mechanism should be in- 
vestigated. Upon indication of a pump be- 
ing inoperative or fauge needle shows no 
movement, make sure there is plenty of oil 
in reservoir and engine is getting lubrica- 
tion by splash, and run irrespective of the 
pump, then you can drive in carefully and 
have the system examined. 

The oil reservoir on the Hudson containe over 
8 fBlloni ot oil In the troughs ftnd ia the reiervoir 
itteir. It ii fitted with n flout iodicfttor which 
•howi the level of the oil by meaaa of a red but- 
ton working in & glAHi tube. This is on the left- 
hand side of the engine. See fig. 2. chftrt 99 A. 

Feed" System— See chart 99A. 

Over lubrication r If the oil pan at any 
time contains more than •seven quarta ciif 
oil| the connecting rods will dip and thua 
create a splash which will over oil the pis- 
tons and cylinders^ more on the right-hand 
block than the left, causing smoke to issua 
from the rauflTler pipe. 

If the englno smokes, drain oil pan and 
measure its contents, as the oil level gauge 
may be stuck. If the oil pan does not eon- 
tain more than the right amount, the oil Is 
probably pumping past the pistons, due to 
worn or stuck piston rings, If this is the 
cause^ new rings should be fitted at once. 

Also remember that the nse of too U|rht m 
grftde of cylinder oil Is apt to cause engine to 
■moke. (The King Co. rocommend "Mobiloil Oar- 
groyle A/*) Always cleaa screen and oil pan, 
w&shtng with kerosene after draining dirty oiL 
(8ee '^cleaning eraok casa,*' page 201.) 

«*The Kind of Lubricating OU to Use. 

At ih9 pr^ont time most lubricating oils 
\ M§ itnlfbt BlllMral oils made from different 
^lintfttf^i of petrol oil in, 

A good high grade gas engine oil la necea- 
IMj because the heat inside of an internal 
eomliustion type of enjfino will burn the 
oil, leaving nothing for lubrication— hence 
wear. Therefore nothing but a high grade 

oil will answer, owe which will stand up un- 
der high t temperature of the cylindere with* 
out thinning down. 

Another point to consider; if rings %re 
tight and compression is good, then it ia 
possible to use a light weight oil so it will 
iplash readOy. A light weight oil, under 
heat, can hold its body and will lubricate 

**Tha chart of aatemobUe recommendatleos, itsoed annually by the Vacaum Oil Co.. Hochaaiar. 
N> Y,, ipfrdiaRi the correct grade of oil for each car and model for the last five years. Ii la tree. 

*Amaant varies on different cars. This is for King, model E. tStudebaker instntctiooa. 
flfaaiBiexB temperattiro in cyUaderi, at lop of axploilon stroke is anproxiraately 2700* F. : the 
minimum tompf>rstnra during suction stroke, about 250* F.- average temperatara daring the four 
0trtikmm, mbout 050" K, These ara tampetaturai la the cylindert to which the outer alda of oil 

itfm /* mrpaBetS ta. 



just the same as good heavy oil, if proper 

8«ine aflgln«s rvqnlr* a Ugbt bodlod qU, otli«n 
A htmiWT OU: Sometimes tbe beav7 bodied oil utrnj 
»ppeAr lo bold Us body or cooaistcncy but under 
b«ftl it will thtn down co&Biderably whereai » liglil 
todied oil wilt hold Iti conaiatency equBllj m welL 

Koto — any oil* no matter how thick or hflATj, 
viU thin down to a certAio extent when heated. 

Wliv* multiple disk clntohAs m-o HBfld wMch 
nm la oU it b verv important tb)it a light bodlod 
oil be uBfd, elae the platea wlU have a tendency 
to draf by i ticking tof ether . 

If piston rings leak, which natarall? lowers 
eompr««slon, then too light ftn oil will pass Into 
III* combastion chamber where the tire and flame 
wiU rapidly turn it to carbon, causing this carbon 
to stick to the Talves. combaatlon chamber and 
spark pltig:. Oonsequent result is Iobb of o\\, 
foulisd spark plugs and carbon deposit. 

The proper oil to use is generally recom- 
mended by the maker of a car. The object 
hag been to secure an oil that leaves no 
carbon depoait and that at the same time 

fives uniform complete lubrication. It must 
old its body and form a lasting Mm on the 
wearing surfaces. If it thiuB down too 
much| it will leave the bearing without lubri- 
cation (see alsoy page 205, bottom) « 

*^A difference In oils Is shown by their 
''flashpoints" and'' humlng points.*' When 

^ Using Oil Over Again, Adding 

*^7slng cylinder oil over again. The cyl- 
inder oil which is drained from the crank 
case of an engine having a circulating sya- 
tern, after every 1000 miles of use, may be 
used for the gear set if it is strained through 
a filter, and is good oil to begin with. 

It if then mixed with fTe«ie. The oil is merely 
charred and is alightly strinrr from the wax 
which has been formed in it. This wax-like coa- 
sistency is the very qnaliOcaCton necessary for a 
gear lubricant is that it holde the oil to the gear. 
The oil should be drained in a pan, mixed with 
grease until the mass assniues the consistency of 
the regular tran amission lubricant familiar to all 
antomobUiats. being neither liquid nor aolid. 

Adding Fresh OIL 
It Is important to note that fresh oil of 
another make should not he added to the 
oil pan before thoroughly washing out the 
old olL Clean, good oil put into a dirty en- 
gine with gummed-up bearings has simply 
no chance of asserting its superiority under 
the unfavorable circumataucea. It has first 
of all to get rid of the gumming round the 
bearings before its lubricating qualitiea 
will be manifested. 

*01eanlng Crsmk Case. 

The system should be drained every 
thousand miles by removing the plug in the 
bottom of the oil pan. After the dirty 

a lubricating oil is heated to a certain point, 
it will give off a thin amoke^ if a lighted 
match is touched to it^ the smoke will lake 
fire with a quick fiaah. This is called the 
"flash point.*' On heating the oil still 
moroj the oil itself will finally take fire and 
burn, and the temperature that will permit 
this is called the ''burning point" The 
flash and burning points are much higher 
in some oils than in others. 

If oil with a low burning point la used in the 
cyliBdcr of a gaaoliuo engine, the intense heat 
will burn it before it cun lubricate the cylinder 
walla and piston. If oil of a anificletntlx high 
burning point is used, the temperature of the cyl- 
inder will not be high enough to burn it, and the 
cylinder walls and piston will be properly lubri- 

One simple method of testing — drain oil which 
liaa been nscd in engine, into a long narrow tube — 
let it Btnnd 24 hours. If good oil it will ahow a 
small amount of black aedifflent at bottom; but 
floatini; above it, the sediment is red in color <by 
transmitted light)* 

Lrfit a poor oil be tested, which is used under 
same conditions. At the end of a few minutes 
it will turn to a dense black. After standing 
24 hours it will show a voluminous black sedi- 
ment aeveral times greater than that of good oiL 

Black aediment indicates sulphur compounds 
in the oit Sulphur is iajurioua to bearings doa 
to lack of lubricating tjualities: also pita the 
TsWea rauBing leakage of compression. 

Fresh Oil, Cleaning Crank Case, Etc. 
oil 13 drained off, the plug should be re- 
placed and about one gallon of kerosene 
poured into the oil pan through the filler 
tube. With ignition switch "off'' so the 
engine will not start, press in on the starter 
button and allow the starting motor to 
crank the engine for about one minute. 
Alao step on the running board and rock the 
car back and forth. Thia will allow the kero- 
sene to wash the interior of the engine thor- 
oughtr. Hemove the drain plug again and drain 
off all the keroaem*. Clean atrainer. 

It is very important that the kerosene be 
entirely drained, for If left in engine it wlU 
thin the fresh oil and cause it to lose its 
lubricating qualities. 

Tha engine will probably unoke more or last 
and there may he missliig, due to the keroiane, 
but after running engine for a while the a moke 
ought to pass away and tbe apark plug can then 
be cleaned and properly aet. 

Do not start engine under its own powetr even 
after new oil haa been put in, nntfl first turning 
It over aeveral Umes with starter, thla it douA 
to eliminate all kerosene from engine dlstrlhutor 
pipe and bearing a. This action pumps the engine 
oil In lla proper chazLnels before it Is run on iti 
own power. 

A "scored" cylinder, means there are 
scratches or cuts in the cylinder caused by 
lack of oil. ^ 'Burnt" heudngs on a crank- 
shaft or elsewhere, means the bearing is 
cut, caused by friction from lack of oil. 

Cause — too much oil: 

pressure adjustment too high. Piston 
pumping oil or rings leak oil. 

Effect — too much oil: Smoking at exhaust; 
carbon in cylinders; pre ignition and 
knocking; carbon on valves necessitat- 
ing grinding; spark plugs become fouled. 

Engine Iiubdcatlon Troubles. 
Oil pan too full; oil Cause — ^not enough oil: 

Oi! level in oil pan 
too low ; oil pressure Lmproperly adjust- 
ed; oil pipes clogged; pump not operat- 
, ing. 

Effect— not enough oil: Overheating; seieed 
bearings or pistons; scored or cut cylinders; 

"Mamifactisren adTlae that oil pan be cleaned freiiuentXy^ especially during cold weather — doe to mora 
raw gatoUne being drawn into cylinder and not being combusted — see page 305, bottom. 

tOaoUng taa lubricating oU; on some racing eara and high speed marine and aeronautical engines aff^ 
hich eompretsion and apeed* the oil is cooled by leading tbe oil out of the engine base, where tarn* 
fi«nitxire can be lowered, before pumping it back Into engine. Castor oil i« a\%o xl&ii4, ^a^i^ ^\%. 
•«Aaietaar tast is the cold test — not to be ovt 25* F. 



Besnlts of Not Using Enough Oil or Too Much. 

If the engine is not getting enough oil, 
the cylinder will become so hot that any 
oil that may have splashed on its outside 
will be burned — the smell being an indica- 
tion of the condition. Further running with- 
out oil will produce a hard metallic knock, 
and the heat will finally cause the piston 
to stick in the cylinder. 

An engine that is run without oil will be 
ruined, for the piston rings and the walls 
will be cut and scratched lengthwise, (called 
"scored'') so that the compression will not 

If the piston sticks or ''seizes" and 
pounds from lack of oil, stop — wait until it 
cools and then fill the crank case to pet cock 
level — also fill radiator with water after 
engine has cooled sufficiently. 

The engine should then be thoroughly in- 
spected before driving, to see if any dam- 
age has been done. If no obvious damage 
has been done, a thorough examination 
should be carried on to determine whether or 
not the running without oil has burned the 
bearings or caused other trouble. This can 
be ascertained by starting the engine, and if 
it pounds or knocks it is a certain indication 
of bearings burned or cylinders scored. 

A new bearing, or any other new part that 
has not worn smooth, requires more oil than 
one that has been run. It is always better 
to give a bearing too much oil than too 
little, but the exact amount of oil required 
for each part of the car should be learned 
as quickly as possible, in order to prevent 

Besults of Using Too Much OIL 

The only place where too much oil is 
harmful in an engine is in the cylinders, 
where it is burnt with an excessive precipita- 
tion of carbon that adheres to the piston and 
cylinder heads, lodges on the valve-seats 
causing pre-ignition, overheating and knock- 
ing, loss of compression, and passes off into 
the muffler, clogging it, giving off much 
objectionable smoke, and ultimately reducing 
the efficiency of the muffler to such an ex- 
ton t that the back-pressure causes a notice- 
able loss of power. 

The local remedy for these is to scrape 
and cleanse the cylinders, grind the valves, 
clean the muffler, and then find the cause of 
the excessive oil supply and cut it down. 

Too much oil in a circulating system in 
which the oil Is simply drawn from the reser- 
voir and forced into the splash compartments 
of the crank chamber, is caused only from 
an excessive supply in the reservoir, of im- 
proper design. 

The oil pressure to be maintained on Ta- 
rious cars shown under ••Standard Adjust- 
ments of Leading Cars''— chart 228. 

**Preventlon of over-oiling: Carbonization, 
sooty spark plugs and a smoky exhaust are 
due to the fact that the oil works up past the 
piston into the com- 
bustion chamber. The 



illustration shows a 
\^ 3a ^ simple but effective 
■ f T j method of supplying 
"^^ sflLAire'^ a return for this ex- 
cess oil to the crank 
case. The piston 
is removed, chucked 
in a lathe, and a 
groove 1/16 in. 
square cut in the out- 
side edge of the ring 
groove just above the 
wrist pin. tSix Hs'^- holes are then drilled 
through the piston at regular intervals and 
are inclined toward the wrist pin at 
an angle of about 46 deg. The oil is 
caught in the groove and thrown down- 
ward onto the wrist pin, not only re- 
moving the excess oil from the cylinder 
but also effectively lubricating the wrist 

If the piston rings leak, the oil passes 
around the rings, out the exhaust, causing 
considerable smoke. Another indication of 
leaking rings is the constant oil soaked 
spark plugs. Therefore it would appear if 
the rings are not in the best condition 
it would then be a wise thing to use heavier 
oil or fit new rings. 


The cause of carbon deposit is due to; (1) 
amount and grade of oil (2) the carbure- 
tion mixture. 

If too much gasoline is used it will cause 
carbon deposit just the same as a poor grade 
of oil. 

Excessive heat will also cause carbon, as 
oil vaporizes. 

Because oil becomes more fluid when it is 
heated, the oil feeds should be adjusted after 
the engine has been running, for if adjust- 
ments are made for eold oUs the flow will 
be much more rapid when it is warmed, and 
the bearings will be flooded, and the excess 
oil will pass by the rings causing carbon 

i^Bmoky BzlUMUit— OaoBe of 
If the vapor is U^bk and fool imiillliig 
it is caused by too "rich a mixture" (too 
much gasoline) ; this ean be remedied in car- 
buretor adjustment. 

If the smoke is whit* or blue, the engine 
is supplied with an excess of oiL 

If the smoke is grey, there is too much 
fuel as well at lubricating oiL 

The reason an engine ezeessivelj luppfied 
with oil smokes is that there is too much 
in the crank ease; the entire lower portion 

•Hm !••«• Ma? ••K^lstlon of Ctrbon to I.ubrlcallof Oil." and pafo 736. 
h»*imm •*Stn* Hho p»$f esa «»«! 703. 

tOldimobilo sdTit« ^b" 


of connecting rod will dip into it and the 
lobrieant will bo forced into the cylinder to 
work hj the rings on tlie piston, then into 
the combustion chamber* thence out the ex- 

Depending upon smoke issuing from the 
exhaufft pipe of a car aa a means of testing 
whetber or not the cylinder lubrication la 
floiricient or over-sufficient Is by no me ana 
conclusive. The fact that the exhaust is 
smoky does not indicate th^t lubrication ia 
complete, or excessive in all cylinders. If 
it iflsues in a steady and continuous atream 
probably there ia suMcient oil in the engine 
and probably, too muchy but if it comes 
in intermittent puffs, it may be inferred that 

one compartment only of the crank case !■ 

I«eaky piston rings are quite frequently 
the cause of excessive smoke — see repair 
subject, * * leaky piston rings. * ' 

OH Brips. 

The average oil drips come from the cap 
screws being loose on crankcase. Other drips 
come from bearings and quite frequently 
from the plungers or tappets above the cam 

On some cars the fan often picks up the 
oil oozing from bearings and throws it over 
the inside of hood. 

«*011 Grooves in Bearings* 

Tb« old'fmaliion»d arrangement of two iimple 
liolM on Uie npt^ar side leBding into oil-wfty either 

Btrttig^ht, aiarr- 

cd^ or ipirAl, 
appe«rft to be 
II good aa Mny. 

But. be it not- 
ed, the oil wayi 
abonld not be 
cut to tJie tfz- 
tx9m9 ttdge of 
the bush, or 
tbeir action as 
reeer voire ia 
apt to be inter- 
fared with. 

Blniilarly ibe bevelling of tbe edges of the buth 
•Jtould llkewUe he diacontinued before raaebias 
Ibe outeide. Tbe arrangements of oil-vrayi ia 
•bown in lIluBtration, (see aUo page 644.) 

^•**Itiinnlng-ln" a Kew Engine. 

Fine groovea <aot visible to the f'ye) are left 
en piston by tbe cutting point of the lathe tool 

vrhea origlnmUy made. Alao poar abaped pita are 
loft bx crindinff machiDo on cylinder wall<« 
When engine la new the projectiona are in Ibe 
fine line stage. 

At ordinary teaapcTature. aaj, .0035 piston 
clparanee, will permit the projectiona to paaa ooe 
anolher. When temperature of engine ia raiaed 
the projectiona will touch from axpaDiion and li 
apeed t« exceaaive tbe temperatura la raiaed whieb 
Increasi'H expanaioo and friction takea place and 
the projectiona imbed theniBelves in the receaaea 
opposite them, which will rauso a stuck or J 
"seised'* piaton <ace page eUO) with the attend- 
ant cobdition of a **acored" or cut cylinder wall 
<eee pagea 201, 653). 

Care is necesaary to use plenty of oil and run 
at normal ratoa of apeed until the projectiona 
gradually change ehape, and are bent over in lucb 
a way that the high polota fill the receaaea. 

After engine haa been run a lOOQ milea with 
care the plat on and cylinder lurfacea become 
very amooth and polished, (see aUo pagea 489 
and 661, why *'plstoo clearance" ra necessary.) 

tPolnters on General 
It is a difficult matter to advise Just what 
tabricanta to nsa on all cars, as different 
manufacturers advise what to use and tbeir 
advice ought to be followed. However, fls 
an example^ the average is given on page 
204^ Studebaker and Hudson. 

A few pointers on lubricating tbe differ- 
ent parts will be given In tbe lines following: 

Disk clutch: There is much mislnforma' 
tion about the caring for and lubrication of 
a diak clutch. Heavy oil often is put into 
■ncii A mechaniani with rather dtaastrous re- 
aolts. At the end of a reasonable dietanco, 
saj 500 miles, the old oil la a disk clutch 
should be removed. There is usually a drain 
plug fitted to the clutch housing and this 
should be removed to let tho oil out, after 
which tho clutch should be rinsed with kero- 
sene, and again allowed to drain completely. 
Thus cleaned, a supply of a light clutch oil 
should be put in until the level is about even 
with tbe bottom of the clutch ahaft. This 
allows the plates to pass through a bath of 
oil, and ia the desirable condition. Borne 
recommend a mixture of a light otl with 
kerosene, but as the proportion varies, it ia 

Lubrication of the Car. 

best to purchase a regular light clutch oil. 
The foregoing does not apply to dry disk 

The tranamisHlon: It is important in lu- 
bricating the gear set that the oil or grease 
should not be too heavy^ for in that case it 
will stick to the gears and be thrown from 
them by centrifugal force against the sides 
of the gearcase. This happens for the first 
few minutes, but after the mechaniam has 
been in operation for some time, all of such 
solid lubricant has been picked up by the 
rapidly rotating parts and thrown from 
them. Very soon, they are free of the very 
lubricant they have been acting upon and 
soon run hot. The best lubricant is a heavy 
oil that will run, or a grease of such con- 
sistency that it will flow. Thus^ when the 
gears and shafts pass through it, it does not 
adhere to them, and there is not tbe tend- 
ency to throw it out of contact with the 
bearing surfaces. There are many speeial 
forms of gearset and dififerential semi-fluidj 
greases and heavy oils on the market and 
the makers have studied these facts so that 
the products perform their function of be- 

**8es pars ^^^- tSee fagea 621. 622. ***8«« alao pagea 489 and SQ7. 
••*Wlt«o englna stands ovar nlgbt, don*t Immedlataly rac« engine to warm It up, bacauae tbe oil bai 
dFaiaed from bearings, cylinder walla, ate, OonaequentI?' it 'a going to take a fev^ minntei to 
labHcAta thaaa paria property. Therefore ftrat let it run ilowly for a mlnuta or •« 

_^ . ji ~- ,1, ^, -M .M *,M» i>» »^i* >■ Ji^MwiM tfiffeM i« i>* tat^w rfifaB ^ f— ^ilr, Mar ftwoMMc taao the 

^^^^ ^^^^^ ' ■ III - lit ■■il« ifc** *^n&t^m ^iaK im. s'aav fi-h v^ 

'scBd«lNUcer Four md >*li 

Enriii« labricmiiOD U the **eirraUtiat ^pl«A" w»t«m with j rf*r pump: To 
nf ^nriBi? • At the bottom of the oil pm if • l^Tf pJoc whtch c»n be Ukrn 

^ .. *^.^ ^>> 'T' ^-^ av;. «,T..* vuia*^ JhKA VaIIaii A^ kMVAAAnj» Ail 

BIT of «iriBi?: At the oottora oi \wb o» p«» w • —j^ p,«, ««tv« t»« op i*»rn 

. .^^ Vfi-; .IJ nl.J oil h»» nui from Ih i plu*, p«mt «»« fallon of kero«enc oil throucb 

%g dMitC I»??^.*t.ii^i«d onl ill dirt lid tVimwit wbkb ««t W^ «H*«rt.d *t th# bottom of p^n. 

iSl two Md one-Half fkUoiu, Part* to l»brie«U •« exfUined iboT*. Koii 

— ■^'.''^nT'I^fi ii««;i nnt ail dirt And tetfiakuii wai<r« ™»j •»▼» K^Pt««:»ww •» Miw uuttow 91 pfta. 

»te-5''SlrSi iH^ iHib ileia oil, WUta p^H^rlf tiled, tjio FOTO kold. ono *od on.-b.lf «1- 
■L?^ fiS Wd" two^ Md ooe^bmlf f»Uoii*, Part* to l.bne-U «» e^t U^ed .boT*. iToio 

v»^». Inbriemttoa *• tbe **ei«ol*tioB tplAth" lyetcra mm deseribod on pft^o 198, 
J^ ^^ i^STS!^ Ko?e the trmMmmiMBi^ wd d^iteb we « «2lit wiib tbo «riiie. 

Ki UiMcsl* «ai a Mo^ma. Oir: Slmdebftker Six and Budsoa Super Six. 

w till* ^.l» * Tbe l^lt-l* ■^•l ^» trmnMiiirtioo tet forward, inatead of rear ns 


ing just light eooiigh to prevent eticklng to 
the revolving parte , It is obviously wrong, 
llieirefore, to put any common grease into a 
geuiet, for it not only acts as above, but 
ua not the ability to get into bearings lilce 
ft fluid m&terml. 

m fllUiig tlio gejurset, put in the lubrkaot 
to A depth about balf the height of tbo 
gearbox. That is, have it come about even 
With the center of the main shafts this wiU 
foapletely submerge the counter-shaft in 
the average georeet design and will bring 
the under face of the main shaft geare into 
the Inbricant. It is important In this con- 
Deetion to see that the packing rings are 
light and prevent leakage where the drive 
iluift emerges from the gearcase and where 
the thaft from the clutch enters it* If 
there is leakage here, xt not only will act as 
a coHector of dirt and dust^ but the gears 
wiU be robbed of their proper lubrication. 

Tha differential housing should hold the 
Inbricant in the rear axle gears, so that 
attention is needed only as stated above but 
sometimes a disagreeable looking rear axle 
la noticed where the oil or grease oozes out 
throQgh cracks or leaks in the rear cover 

plate or through the axle tubes onto the 
wheels. This is not so common a fault as 
it used to be when axles were not designtd 
BO well to trap the oil and keep it wher« it < 
belongs. However, an occasiona! eareloM 
driver will let his axle get in this condition 
by not having a proper gasket between the 
differential housing cover plate and the 
housing itself. It is not much trouble to cut 
a gasket if the old one gets worn or out of 
shape, and it saves the bra^e bands wMck 
often become oil soaked and slip. 

tTlie axler In some cases, a heavy trans- 
mission oil is recommended for the axle but 
in moat instances it is best to use either a 
sem-fluid grease or even a heavy grease. 
There is less chance for the gears to throw 
these, and the space is smaller so that it Is 
next to impossible for the grease to gel 
away from the lubricating points. It li 
next to impossible to gire any fixed rnlt 
for rear axle lubrication. There are so many 
designs, and where a heavy oil or a greaae 
will work satisfactorily in one instanee, 
some other form is better in au other, 

Dodg» tor mitancfl uftes 600W — tt^im cylinder 
oil two piirt8> iad one part mediaia groiBfi, 

*The Use of OrapMte la the Automobile Engine. 

Tilt use of flake motor giapMte mlxad wltli 
C7U3id«r Inbncating oil wbon properly mad will 
miproTa comproABlon, decreaEe the amount of oil 
requr«d« fill op scores tn the cylinder walla, pro- 
v«Dl Tal^eg and riiigH sticking and thereby cure 
•mokj «xhauat. 

A fr«Bt deal of prejudice baa existed aninit 
fraphit«' labrication dtio to ignorance. when 
automobile! IBrit came on tbo market,^ ebanffenrs 
IP Quid go to a hardware etore lo buy grapbita to 
eilx w^ith tbeir greaie and would get DLxon'e 
Flake Gr»pbite No. 1 which is Intended for lu- 
brieatlon of tteam c^linderB and other heary 
work. Then tbey would use about five tlmea 
ioo maeb of it and tronb|{» would result. Of 
eoQZve, graphite w&a blamed. However, anjrone 
who baa ever taken the trouble to investigate 
Dizen graphite automobile lubricants bas seen 
tta ■enae of their claims and would use no other 
kind Qf labrication. It stands to reason that 
wlftvi bearinga aad gear teeth are polished with 
In* lUika graphite that there are actuatlr no metal- 
lie tnrfaeea in contact and htnce there can ba 
AO wear, no heating and practicslly no friction. 

However, assuming that graphite is an ideal 
lubricant certain requirements Kr« necessary, for 

For aplaali olUng syttamt tht Dixon Co. re<;om- 

mend adding a scftQt teaapoonful of motor grap^ 
ita to each qinazt of oU In the crank caia and 
then idd another teaspoonful st the end of aaeh 
one Ibouaand miltis. The graphite may be xaixad | 
with s littl<<< oil and poured down the breather. ' 
Tou will notice that this is a yerj small amount 
of graphite but it is all tbsl is required. 

For force feed ayit«m it is not adTlaable le 
Mix the graphite with the oil on account of the 

possibility of clogging 

Bomit of the small pAt" 

A small amount of dry graphite may be plaead 
on the liand and permitted to be inhaled throQgh , 
the air intake of the carburetor directly to the J 
cylinders. This shonld be done abont once a week 
when your car is in ordinary serrice. 

More graphite can be used when it is iatro* 
duced in the dry form becanse part of il ia ba- 
mediately blown out through the ezhauit. 

On account of the location ol the magneto om 
Ford cars and the possibility of short drcnltliit 
It we do not recotninend the use of graphlta Is 
the crank case or transmission case of thOM 
cats. This is merely a precaution that we iaka, 
although we know of many Ford owners who OSf 
graphite in their engines with entire salisf action. 

How Unvaporlzed OasollBe TMns The 00. 

IHmrWflt Tlpor thai is not completely consumed 
la Me Mglno doea one of three things; it either 
pesatl out into the exhaust in an unburued state 
and la wasted, is deposited in the form of carbon 
srithtn the cylinder, or eoiideiiAetf and runs down 
past pistons into the crankcase. 

Tho lirat of theao Is the most dlroct loss, but 
the other two are e<iually important in the lon^ 
ran- A carbonised engine is of itsplf inefficient. 
'"Carbon makes the engine miss, makes it over- 
haat and pre-ignite. All of these things are ture 
to ahortoii the life of the engine. When the im- 
htLTDOd fnal nma down past the piston It destroTB 
llio aeal between piston rln^a and cylinder, re- 

moves the oil which is to protect the anrfaeo ol 
the cylinder and piston from friction and wear and, 
lastly dilutes the lubricating oil In the crank- 
case to such in ejctent that in time it becomes 

Manufacturers are adrlsing tiow that the eraak' 
case be drained STen more fro^nautly than •?<« 
before for this Ter7 reason. As cotd weather ap^ 
proaches. the necessity for frequently refiUlng 
completely with new oil will become more Im^ 
perative. Either the motorist is forced to dr&lll 
oat his oil and refill with fresh at an inereaa^ 
outlay or he must suffer the Gonseqnenees of tOkm 
engine damaged by insufTicient Inbrlcatfon. 

**S*a page 623. tOroaao working ont axia ands on brake bands — cause bj^es to flip. 
*A free booklet* advising just where graphite as a lubricant can be useo^n a motor cfar and the 
kind to nee. can be obtained by writing the Joaepb Dixon Crucible Oo., Jersey City. N, J, The wrtteir 
kaewiag ths isportacee of good lubricant, recommends the use of graphite. 




IGNITION : LOW TENSION COIL. Purpose. Brief Explana- 
tion of Electricity. How Electricity is Produced. Methods 
of Generating Electricity. Low Tension ''Make and Break" 
Ignition— using a Low Tension Coil. 

Principle of Ignition. 

There are three things required before a 
gasoline engine will run. These three things 
are absolutely essential. First, it is neces- 
sary to have a mixture of gasoline and air 
in the engine cylinders. Second, this mix 
ture must be compressed, and third, there 
must be a spark to set fire to the compressed 
mixture. The third thing required to make 
the engine run is the one which is most 
difficult ta understand, if the reader is not 
familiar with electricity. The system of 
ignition, as it is called, is usually made up 
of certain electrical devices which probably 
give more trouble to the motorist than all 
the other mechanisms on the machine. 

In order that you may thoroughly under- 
stand the principles upon which the various 

Ignition systems are built up, and how these 
systems are operated and maintained. It is 
well to start at the beginning. 

The original and first method for igniting 
the gas In a gasoline engine was by the 
means of a ''hot tube" or flame, but this 
method now being obsolete, we will deal 
only with the electric ignition. 

The ignition systems used on automobile 
engines at the present time are all electri- 
cal systems giving an electric spark which 
passes in the cylinder of the engine and 
sets fire to the compressed mixture, and as 
you will be dealing with electricity and elec- 
trical apparatus in these systems, the first 
thing to know is how electricity acts and 
how you can make it do work for you. 

What Is Electricity? 

No one can tell you just what electricity 
is; we know how it acts and how it moves 
in the same way that we know how the force 
of gravity acts. 

If you throw a stone into the air it will 
eome down again, but you cannot explain 
why, beyond saying that the force of grav- 
ity makes it come down. You cannot say 
just what "gravity" is — so it is with elec- 

Electricity is in everything — in your body, 
in your clothes, in the magazine you are 
reading, in the chair upon which you are 
sitting — and the only reason you do not feel 
a shock is because the electricity is not in 
' * motion. * ' 

If you put a water wheel in the middle 
of a pond, the wheel will not revolve, no 
matter how deep or how large the pond 
may be. 

To make the wheel revolve to get any 
work out of it, you must place the wheel in 
position that the water may flow from a 
high level to a low level, and in flowing, 
move or push the wheel around. 

There must be a current of water before 
the wheel will move — so in electricity — 
there must be a ''current or a flowing of 
electricity" before you can get any work 
out of it. 

If you want water to flow, you provide 
a patii for it downhill, or, in other words, 
you allow it to take a natural course from 
a high level to a low level. 

Tou can pump water to a high level and 
then get it to flow through pipes or along 
a stream. 

When water is pumped into a tank that 
is, say, 100 feet high, you know that there 
will be a certain pressure in the pipee lead- 

ing from the tank, and if you want to know 
how much pressure there is, you will meas- 
ure it in so many pounds pressure. 

At the same time you can measure the 
quantity of water flowing out of the pipes, 
and you can say that so many gallons will 
flow in a minute. 

You are no doubt perfectly familiar with 
the measurements called a pound, gallon and 
minute, and if you were told that 200 gal- 
lons of water were flowing out of a certain 
pipe in a minute at a pressure of 60 pounds, 
you would have a pretty good idea of the 
current of water referred to. 

Now, when you come to work with elec- 
tricity, you should be able to understand 
the current in the same way, but you will 
find that the measurements of electric cur- 
rents are not stated in gallons and pounds, 
but in other terms, as, amperes, meaning 
the quantity of current flowing; volts, mean- 
ing the pressure, causing it to flow; and 
ohms, meaning the resistuic^ offered to the 
flow of current. 

How Electricity is Transmitted. 

Electricity produced In one place may be 
transmitted to another place^ provided a 
path is arranged so that it may return to 
where it started. It will not flow if there 
is no circuit; that is, a continuous path. 

If the circuit is broken, the flow will im- 
mediately stop, and will not start again un- 
til the circuit is once more completed. 

Copper wire is usually used to take the 
electric current from where it is produced 
to the place where it is to be used, and an- 
other wire may be used to bring it back 
again, the first wire being called the ' 'lead," 
and the second the "retaxn." 


If there is any way in which the current 
m*y leak trom the •lead wire and return to 
the ttarting point without going through the 
entire circuit, it will do so, and this leak- 
age ifl c ailed a sbort circuit or ground, 

•♦A conductor: Anything that will permit 
a eorreot of electricity to pass through it is 
called a conductor; all metala are conductors, 

Xnaolaton: Bubstances such as rubber, 
diina, porcelain, glass, wood 0bre and mica 
are called non-conductors or Insulators* 

A wire Is Insulated to prevent leakage of 
current into any metallic substance it may 
touch by wrapping it with cotton or silli, 
which is soaked with rubber to prevent 
dampness from getting in. 

When dry, cot too Kod tilk if* iofaUtort. but 
damp eotl^Q ind itlk 

ftl WAi«r l« « conductor, 
ceftte to be IntuUtors. 

Explanation of Voltage and Amperage. Also **Serie8/* 
and * 'Multiple" Connections. 

WMle all metals are conductors, some are 

better conductors than otliers; a copper wire, 
for instance^ will pass a larger current than 
a** iron wire of the same size. Due to the 
fact that copper has a lower resistance. 

If a wire has more electricity passed 
through it than it can easily conduct, heat 
will be generated, and it may get so hot 
that it will melt, 

The larger a wire is, the greater is the cur- 
rent that it can pass without heating, (volt- 
age being the same.) 

Copper is in most general use as a conduce 
tor of electrlcityp because of its low resist- 
ance; silver is a better conductor, as it has 
a stilJ lower resistance, but is not used be- 
cause of the expense. 


A current of electricity flowing in a wire 
may be meaaured Just as a current of water 
flowing in a pipe may be measured. 

The amount of water that flows through 
a pipe depends on the pressure, or head, and 
the friction in the pipe. The volume of 
electricity that flows through a wire de- 
pends on the pressure or voltage at which it 
flows and the ohmic resistance of the wire, 

Volts (pressure). The quantity of water 
flowing through a pipe depends largely on 
the pressure. The amount of electricity 
flowing, or the strength of current in am- 
peres depends in part on the pressure in 
volts. Thus the amount of current flowing 
is measured in amperes and the pressure 
causing it to flow is measured in volts. The 
Tolt is the practical unit of electromotive 

The eloctro-motlve force, usually written 
E. M. F., is the total force required to cause 
the current to flow through the entire cirauit. 

The unit of electromotive force b the'volt. 

Ampere (current) a current of water flow- 
ing in a pipe is measured in gallons per 
second or cubic feet per second. An electric 
current is measured in amperes. Thus we 
say the strength of one ampere flows for 60 
seconds, then the total quantity is 60 am- 
pere-seconds, or 60 coulombs of electricity. 

The coulomb ii the unit of quantity which 
eqojiif th^ rat^ of flow X time, ai aiopcrc tecoods. 
Oup uapere boar would equal 3600 coulomb*. 
The ampera* therefore it the curreot titreniflh, in* 
trfitity 0/ earrent or rate of flow, but ia thit la- 
•trurtioD we hav« referred to the ampere as the 
volmna or qnAntlty of current Urtwin^. 

Tht velocity of electricity through a copper 
wire it naid to be 238,000 milea per srcond. 

An ohm is the unit of electric resistance. 
Such a resistance as would limit the flow 
of electricity under an electromotive force 
of one Tolt to a current of one ampere. 
For instance, we speak of a certain size of 
copper wire, a certain length having so 
many ohma resistance. Iron wire oflfers 
0% times more resistance to the flow of 
current, than the same length and sijr^e of 

copper wire, therefore if it is not of suffi- 
cient size to permit the free passage of cur- 
rent, the wire will heat. 

The watt ia the unit of eleetriQ power, 746 
watti equal oue horae power, MuUiplj'ing the 
atoprrea by the volta givea watts. 

In order to explain tbe meaning of volt- 
age and amperage more clearly, we will use 
a hydraulic analogy, which gives the ex- 
planation as follows: 

Usually the ignition coil is so made it 
will work with a pressure of 6 volts. The 
resistance (see page 200 for meaning of this 
word) that the electricity meets in the 
wiring of the ignition system is so great 
that if we only had a pressure of 1 volt, 
this would not be saffieient to force enough 
current through the wiresJ As the pres- 
sure increases the quantity of current that 
flows becomes greater It has been found 
that a pressure of 6 volts is sufficient for 
most Ignition systems which require from 
1 to 5 amperes. 

Series connection. The way we build 
the pressure up to 6 volts, with dry ceOs 
as an example, which give only 1^ or 1% 
volte each, is by connecting them in "ser* 
ies*' as it is calledJt 

fS^ f:S^ f:5tl 


I'vpf, I.- — ^rompiting dry vellm or alurage 
b«!i»'>> *tlU witli pnili of water. 


Fig. 2, — Drjr celts connected in *'aeriaa" 
aimiiar to paila of water plac'cd at ahown. 

'Frenouneed leed, not lead. **The best conductor ia iilTer« De%t beet, copper, then alominiua, alne, 
brsta. plaiiaum, iron, nickel, tia. lead, German lilver, aatimony, mercury^ biamuth, carbon, wet«r« 
Tlmt it will be teen that iron offpra more reaiatance than copper, and carbon and water more f 
aiatan«e than iron. Non-condnctors are aUti*, marble (if no metallic veini), oila^ porc^laia, fltia, 
ntlfber dry paper, silk, futta pcrcha. shollae, ebonite, etc. fSee pape 427, aiie wire to use. 
ttSlorsfe hsttery c^ls ^re 2 Toltt« large or imalt. The preaaure ia built np by adding towt^ c%\ka S»^ 



This can be explained by referring to oar 
hjdraulic analogy^ as followa: Suppose we 
liad tlireo p&Us of water, each of them 1 
foot high, as eh own in fig* 1, and suppose 
we had three dry colls, each of them giv- 
ing a pressure of 1 volt, we will say for 
the aake of eimplkity. If we would take 
ihea^ three pails and set them one on top 
of the other, and make an opening in the 
bottom of the three pails, connecting the 
opening in the bottom one with a pipe, the 
pressure in the pipe would be three times 
as great as if we had only one pail. That 
is, we would have a bead of 3 feet of water 
ia tho pipe and the water would squirt up 
approximately 3 feet in the air, as in fig. 2. 

When the eella are coimected so that 
the pressures in them are a4ded. It is called 
a * 'series*' cdmection because it corre- 
sponds to putting the paila of water in a 
series one above the other. To make this 
connection, which is shown in fig. 2, we 
connect the positive terminal of one cell 
with the negative terminal of the next, the 
positive terminal of that one with the 
negative of the next, and so on. Finally, 
mnning one of the wires of the outside cir* 
euit, from a lamp in this case, to the nega- 
tive terminal of one end cell and the other 
outeide wire to the positive terminal of the 
other end cell. Since there is a pressure of 
1 volt, we will say, between the positive 
And negative terminals of each ceU, we 
have simply added the voltage of all the 
other cells to it, just as we added the pres- 
sure in the other pails of water to the first 
one when we set the others on top of it. 

Series connection means that the carbon 
(positive pole) of one cell is connected to 
the Elnc (negative pole) of the second; the 
carbon of the second to the zinc of the 
third and so on. This leaves the carbon 
of the last cell free to be connected with 
the outside circuit, likewise the nine of the 
first cell. 8o, when the entire battery of 
eeEs flows from the outside carbon through 
the lamp or ignition coO, or whatever is in 
the outside circuit, and back to the battery 
through the sdnc of the first cell. 


Fir- 8. — ^rj celli co&tiected In **parftl- 
I«r' or ''tnampl*/' limiUr to p»ilt of 
witcr conn««l«d one with the other. 

Parallel connection: There is another 
way in which we can attach the three pails 
ol water to the pipe, and that is the ar- 
rmngement shown in fig. 3. Instead of set- 
ting one pail on top of the other we have 
Ihem all on the same level and If we con- 
nect the bottom of each one to the pipe 
the water will flow through the pipe, but 
W^ wlU have only one foot of head and the 
water will squirt only as high as the level 
of that in any one of the three pails, that 
1% the preesure would be no greater with 
Ike three pails connected this way than it 

is if there was only one pail connected with 
the pipe^ but the water will flow three times 
as long. 

We can do almost the same thing with 
the electricity in the three dry cells (or 
storage battery cells) as we did with the 
water in the pails, that is, we can connect 
them up so that the pressure of each of 
them is added to that of the rest, or we 
can connect them up so that tho pressure 
of all three is equal only to that of one, and 
like the water, the current will fiow 3 times 
as long. 

This arrangement in fig. 3, is called the 
** parallel," or ** multiple" arrangement, 
and corresponds to connecting the pails of 
water to a pipe when all of them are at the 
same leveL When we connected the pails 
of water in this way we simply added to 
the capacity of one pail without increasing 
the head or pressure. 

When we connected the three pails set on 
a level it was just as though w© multiplied 
the size or capacity (amperage) of one pail 
by three. 

In the multiple or parallel arrangement 
of a dry cell (or storage battery cells) ws 
simply connect aU the positive terminals, 
or plates, and all the negative terminals, or 
plates, tegetherj and the effect is merely 
that of adding to the size of the plate or 
capacity of the cell. When we connect the 
three cells in multiple or parallel, as in fig. 
3, we have multiplied the capacity (amper* 
age) of the cell by three, but we did not 
increase the pressure. 

If we Increase the sl«e of the plates In a 
cell we lengthen the time during which It 
will give a current of electricity. 

If one dry ceU will give 1 volt for one 
day^ three dry cells would give 1 volt for 
three days if connected in multiple, but If 
connected in series, as shown in fig. 2, we 
would get 3 volts presaare, but the three 
cells would last only one day. This can be 
explained by considering the water pails 
again, with the pails one on top of the 
other, giving a 3 -foot head, the water would 
run out in one-third the time that it would 
if the pails were connected together as at 
the right of fig. 3, where tbey get only 1- 
foot head. It will be seen that in series 
connecting we increase the voltage hot 
leave the volume or amperage the same, and 
in parallel connection we increase the 
volume or amperage, but leave the pressure 
or voltage tho same, and in both cases the 
watts will be equal. 

In order, then, to get a pressure of 9 
volts, with dry cells giving 1% volts each, 
we simply need to connect four cells in 
series, for then we have four times 1% 
or 6 volts, which is pressure enough for 
the ordinary ignition system. 

As the voltage has a tendency to drop 
when in use, 6 cells are usually plmeed Id 

It is not well^ however, to use more eellt 
in series than are needed, for good working, 
because the excess of pressnre would force 
the electricity through the circuit at too great 



• rate or amperage and this high earrent 
w«uld damage the vibrators of the spark 
eoiifl aa will be explained later on. 

With tbe four cells connected in aeries 
ftad the total gtvlng 6 volts pressure, we 
have the life of only one cell, that Is, the 
foftr cells connected this way will not last 
anr longer approximately than if we had 
only one cell. 

Multlple-serleB cotmection: We can dou- 
ble the life of the battery, thus obtained by 
coimecting the four cells in series, simply 
bj €0X1 nee ting up four more cells in series 
And then connecting the two sets of fonr 
eella each in "parallel or multiple*" Tbe 
Arrangement is illustrated in fig. 4, in which 
eue we havo three of the l-vo)t cells we 
■p^ftk of, connected in series and three more 
in series, with the free negative terminals 

>of each set tied together and the free post- 
tiv0 terminals of each set tied together* 



: :t 


Fit* 4- — Two fieU of celli connected 
In "parnUel/' Each iH eoDii««ted in 
'*i«nei;*' called "multiple lerlet/' Not« 
the coiapftriBon. 

Here we have obtained a presBure of 3 
volti by connecting three cells in series and 
have doubled the life t/r capacity (amper- 
age) by connecting in parallel another three 
which have been connected with each other 
in aeriea. The effect is just the same $ja 
if we had taken three cells of double the 
eapaolty (amperage) and connected tbem in 
•eriea. We would accomplish the same ro- 
■alt with water pails by making two piles 
of three each and connecting both to the 
same pipe, as indicated in fig. 4. Here we 

have obtained a head of 3 feet and doubled 
tbe capacity (amperage) of our source by 
doubling the amount of water. 

In the cell parallel arrangement, illus- 
trated in fig, 3, tbe curreot Bows from the 
carbon of one end cell through the circuit 
and back to the battery through the zinc of 
the same cell, so that the current from the 
first cell does not have to flow through the 
second and third cells in order to go through 
the circuit and back to where it started, 
but is able to How past them. The current 
from each of the three cells flows into the 
wire connecting their carbons and on its 
return flows back into the cell from the 
^vire connecting their zincs. If you have a 
current of four amperes in the circuit, each 
cell will be giving one-third of the current, 
and only one-third of it will be flowing 
through any one cell. With two sets in 
multiple only half this amount of current 
will be flowing through each celL 

Separate seta If used for ignitloQt In a 
motor car where dry cells and vibrator coUs 
are used for ignition it will be found neces- 
sary to use two sets of cells which are not 
connected to each other, but either one of 
which can be switched into the circuit if de- 
sired, lo fact, it will be found almost 
necessary to change from one set to the 
other every 25 to 50 mites. Otherwise the 
engine will begin to miss and finally will 
stop. This is because tbe current flows 
through the cells so rapidly too much gai 
forms for the depolarizer to take care of 
and the cells polarize. After resting a 
while the cells will be restored or will re- 
cuperate, at least in part, to their former 
condition and can be switched on again. 

But if there are eight cells connected in 
two sets of four In series and these two 
sets connected in parallel arrangement ex* 
plained, the quantity or amperage of cur- 
rent required from each cell is lessened and 
they last very much longer^ — see foot note 
bottom of page 211, also index. 

tMeanlng of Beslstance. 

Electricity will flow more easily through 
some conductors than through others be^ 
canae there is a difference in their Tesla- 
to the flow of current. 

better conductor it is. The greater tht 
resistance, the less total current can paae; 
the pressure or voltage will dropt and the 
volume (amperage) wOl be reduced. In 
forcing a current through such resistance, 
heat & produced, and Qm greater the re- 
alBtance the greater will be the heat (see 
ohms page 207, also index). 

PosltlTe and Negative Tenoinals. 
Generator terminals: Every generator of names given to the points from, one of which 
eleetrielty has two terminals; a positive the current leaves (positive) and to the 
(-I-) and a negative ( — ), that being the other of which it returms (negative)/ 

Everything presents more or less resis- 
taaee to the flow of current, and the le«a 
that a substance presents, tbe 

*Th» enrreBt Alwtya flows in the uxna direction, from the poftitive pole to tbe nesetive pole; it 
leavM the g«neretor bf tbe potittve pole end ret^mi hj the ncfillTe. 

Coiweciiofie cen be (p-ounded either from the aefetive or poeitlve pdle — it m&kea no material 
^Hfertniee. Mannfecturore ai e rule ^ouod the iKieitire terminal of e itoregre bettery to the frmme. 

fEeeJjtance ie thit property of aa electrical condtictor hj whkb It oppoaes tbe flow of an eleetrical 
eaJTeoit. for iaatance, carbon, iron wire, Oerman ailver and water will permit enrrent to flow threti^h, 
bat il op>p4>ee< or offers resiitance to the flow — ^lee «bm, pagre 207. A rbeottal ia a derice for the pur- 
peae of Tanrin^ tbe resistance of an electrica! corrent, see pages 474 and 160, tTermed a potential 
d^ertnee or tinergj lost. For instance, "two volti loat on a line," means tbii much preastire ia loet 
\m ttodiDC tbe current through tbe line. 


f Pig. 2 — The Ignition Storage Battery; a Oliemiciil Qen- 

I erator of ''Direct** Flow of Electric Current. Contained 

^^_ in B battery box, Soroctimis called an accumulator. 

^^B The Storage Battery will b150 supply electricity to op- 

^^F erate a Jamp Spark or High Tension System of Ignition 
' or A Low Tenfiion "Make and Break'* system. The Stor- 

age Battery for ignitjoo consists of three cells placed in 
an acid-proof box. (See instrnction on storage batteries.) 

These cells are covered over with a nard mbber or 
coat tar eomposition, leaving the lead tugA projecting. 
These logs connect one cell^ to the other and two end» 
are left **open, >* one it '*Pos«tivc'* or Norths and the other 
a * 'Negative** or South. They are called •* Positive'* or 
"Nefatlve** Terminali. "Wires are connected to these 
tennmaH and the current is conducted over (ho wires to 
the ignition system. 

When the Storage Battery is *'run down*' it is *'re* 
charged" by attaching wires from electric wires to the 
battery. (Will be explained later.) 

The cells contain lead plates <N) negative and <P) 
positive, aad are immersed in an acid solution. 

Each cell gives two volts and are usually placed in s 
box and connected together, making a totml of six volts 
this being the usual pressure recruited to operate a coil, 



Fig. 3— The Dynaino; a x«ow Tension. 
Mechanically Generated, Direct now of 
Bleetrlc Oorrent. The Dynamo will lap- 

Jly electricity to operate the coil of a 
ump Spark or High Tension System of 
ignition or a low tension **Make and 
Break*' System (not in tuo on entomobilet 
to any great extent). 

The Dynamo is more adapted for generat- 
ing current to recharge the storage battery: 
the storage battery tnen supplies light and 

Small "direct** current generators are 
also u-sed on stationary ana marine eagines 
for ignition^ where "make and break or 
*'wipe'* spark ignition system la need. 


The Dynamo has an ' 
Field, meaning that the 
magnetixed electrically. 

Electro Magnctie** 
'pole piece*** are 

* Permanently * * mag- 
(will be described 

The Magneto has 
ne tiled "pole pieces* 

The Dynamo generates a "Direct'* or 
continuous flow of electricity, meaning the 
current flows continuously, whereas the eor^ 
rmt in a magneto is reveraed and flows 
''altematfity'* and is not a direct flow. 

The magneto is used in a different man* 
ner and is a separate end distinct system of 

The Dry Cell Battery (a Primary Cell) : 
a Chemical Generator of a Dlroct Flow of 
Electric Cnrrent will aUo supply ekctricity 
for ignition, but is not ri>llable. Continuous 
use of dry cells will extiaust thom or run 
them down rapidly and tUu prc£j>ure drops 
accordingly and thereby causes a "weak*' 
spark. This battery will recuperate* how- 
ever, if left standing for a while unused. 

The dry cell battery is better adapted for 
ringing door bells or telepnone work where 
the work required la not continuous. 

The dr]r cell contains no liquid, but 
.■erely moisture* hence its name— Dry Cell 

A Is the filling or electrolyte, usually con- 
■ietlng of chloride of xinc, sal ammoniac, 
•nlphate of lime and powdered charcoal 
(don*t confute this electrolyte with that 
used on a store ge battery). 

Six cells connected in a scries coonec* 
tion is usually the eomt>lnation for a set 
for ignition. 

The positive pole of the dry cell is the 
carbon. The xino being the negative. 

ignition and will be described Ister. 


Fig. i. 
Sectional View of 

m Dry 

Fig. 4A. 
Complete View of 

ft Dry 

OHAMT NO. 101— €bemlcal and Medxanicgl QeneratorB of a * 'Direct** How of Electricity. 
reference is made here to Mngnetoa; this will be treated later, under a separate heading. 

'^- - 



How Electricity is Made to Do Work. 

Flow of cerrent: The ourrent only flows 
when the two terminals, or poles, are con- 
nected hy a conductor. 

A current will flow if any opportunity is 
presented; if there is no regular conductor, 
moisture will often make the connection. 
Because of this desire to flow, the current 
may be made to perform work. 

If the circuit includes a coil or lamp, the 
current in flowing through the circuit from 
the positive pole to the negative pole is 
made to light the lamp or pass current 
through the coil. 

The circuit, with the lamp or coil, presents 
a resistance to the flow of the current, and 
if there is a short circuit that presents loaa 
resistance, the current will return by it in- 
stead of going through the coil or lamp. 
Therefore, the circuit must be so arranged 
that the current cannot return to the gener- 
ator without doing the work set for it. 

A switch is provided to close this circuit 
when work is desired and to open the cir- 
cuit when work is not desired. Therefore, 
for ignition, instead of m switch a timer or 
commutator is made to open and close the 
circuit at the time the spark is required. 

Parts Necessary to Produce the Ignition Spark. 

While there are several methods of pro- duced; a timer or cam arrangement, by 

ducing the spark in the cylinder at the which the exact instant of the spark may 

proper instant, they consist in general of be controlled, and the circuit, consisting of 

the same parts. the necessary wires or conductors. 

In the first place, there must be a genera- 
tor to supply the current of electricity; 
■pack pings or sparkers, also called igniters, 
in the cylinder, at which the spark is pro- 

Whatever the system may be, the current 
is produced by some kind of generator, and 
therefore a description of generators will 
be given before describing the systems. 

Methods of Generating "Direct" Electric Current. 

A current of electricity may be generated 
by chemical means, by cells; or mechanical- 
ly, by a magneto or dynamo. (The magneto 
will be described further on as it generates 
•a "alternating" current and the dynamo 
"direct" current.) 

Chemical Generators. 

Oella are of two kinds, "primary" and 
"secondary;" primary cells actually mak- 
ing the current, and secondary cells storing 
the current and giving it out as needed. 

A dry cell or storage battery cell pro- 
duces a "direct" flow of current and would 
be termed a "chemical" source of elec- 

Tlie* primary cells used for automobile 
work are called "dry cells," and consist 
of zinc cups, in which are placed sticks of 
carbon (see chart 101). 

The eups are lined with some substance 
like blotting paper, and the space between 
the carbon stick and the cup is packed 
with bits of carbon and the necessary 
chemicals. The blotting paper and carbon 
bits are moistened with the proper solution, 
and the top of the cup sealed with tar, so 
that it is watertight. The zinc cup and 
the carbon stick each have a thumb nut at 
the top, called a "binding post," to which 
the wires are attached. 

When the circuit is closed, the current 
of electricity flows from the carbon bind- 
ing post over the circuit and back to the 
e^ by the sine binding post, the "carbon" 
htmg the "positive p<ue," and the "zinc" 
the "n^^ative pole," in this type of cell. 

Dry cells have a pressure or voltage, of 
about 1% or 1% volts, and the volume of 
the current they produce, called the "am- 
perage," depends on the size of the cell. 
The ordinary dry cell used in automobile 
work gives a current of 20 to 30 am- 

When in use, a primary cell becomes ex- 
hausted, and the voltage drops gradually. 
When it has reached a point where it does 
not give sufficient current, it must be 
discarded, and replaced with a new one. 

It should be remembered that dry cells 
are intended for "intermittent" •service, 
as for ignition starting where a magneto 
is used, but for continuous service, the dry 
cell is not a suitable source of current. After 
the engine has started dry cells for ignition 
are not very satisfactory fer they become 
exhausted in a short time. 

For continuous current service the most 
efficient means of obtaining current is by 
means of a storage battery consisting of a 
battery of "secondary cells," or as it is 
sometimes called an "accumulator." This 
chemical type of electric generator is in 
more common use for ignition than the 
dry cells in connection with a dynamo — 
which will be explained further on. 

**8econdary cells, also called "storage 
cells," or "accumulators," are usually 
charged with current from a lighting cir- 
cuit, and may be recharged again when ex- 

*Th« l0M eoBtlmumsIy eurrent it natd from a dry cell the longer it will last or the more efficient 
iftwffl W. 

I telterlM win be trwitod under a separate instruction. 



A atorage battery coeeista of two or more 
■tor age cells. Eacb cell givcB about Z 
7olt8y therefore, a atorage battery with 
three cellB would give 6 voltai and is termed 
a ''chemical generator," tbat is, it will 
generate electricity by a chemical action 
when discharg-ing after first being charged 
— see page 447. 

A storage cell is made of prepared lead 
plates, placed in jars made of hard rubber 
or eeUuloid and filled with a solution of snl* 
pburic acid and water, called the * 'elec- 
trolyte." The jar ia filled with electrolyte 
trntU the plates are covered, a co^er pre- 
senting it from spilling, A hole in tha 
coTer, dosed with a plug, is used for exam- 
ining the condition of the cell, and refilling 
it when necessary. Through evaporation, 
leakage or spilling, the level of the electro- 
iyt© may get below the top of the plates, in 
which case the jar should be refilled* enough 
electrolyte being added to bring it to the 
correct level. 

Blectrolyte is made by adding one part 
of chemically pure sulphuric acid to— from 
three to nine parts of pur© water— prefer- 
ably distilled water. 

An instrument called a hydrometer is 
used to determine the correct solution, and 
when floated in the solution its scale should 
read about 1290 sp. gr. 

fThe terminals of a storage cell are 
usually marked with signs to indicate the 
poles; a "plus sign, ^' the same that is 
used in arithmetic, being the "positive 
pole," and a "minus sign'' being the 
"negative pole.*' 

The poles are often painted^ as well, red 
being the positive and black the negative, 

A storage celt has a voltage of a little 
over 2 volts, and this will drop slowly to 
1.8 volts, when it requires recharging. In 
this it is like water running out of a tank, 
when the tank is empty it ia necessary to 
refill it. 

Cell CoBnections. 
On pages 207-9 the "principle" of cell 
eonnections was explained in order to ex- 
emplify the meaning of volts and amperes. 
Cell eonneetioai will now be explained. 
Bear in mind the same principles apply to 
storage battery cells. 

One cell in a storage battery or dry bat- 
tery will not give enough current to pro- 
duce the spark required to ignite the mix- 
ture, and therefore, three, four or more 
are used, connected together. 

The most usual form of connection is in 
lerlea; the negative pole of one cell is con- 
nected to the positive pole of the next, so 
that the current from one cell must pass 
through all of the others in order to return 
to where it started. (See chart 102, fig, 1.) 

This method of connecting increases the 
▼oltage as many times as there are cells; 

for instance, if there are four cells of 1% 
volts each, the voltage of the battery of 
cells will be six volts, The volume or am* 
perage does not change, being the same that 
it is for one cell. (See fig. 2, page 207.) 

Another method of connecting is in pftr- 
allal; all of the positive poles are connected 
to one wire, and all of the negative to an- 
other. (8ee chart 102, fig. 2.) This givei 
the tame voltage (pressure) as one eellaJ 
but increases the amperage (quantity) ai ^ 
many times as there are ceUs. 

A third method is to connect the cella la 
multiple series. (See chart 102, fig, S.) 
In this the cells are divided into two equal 
groups, each group being connected in series, 
and the two groups being connected with 
the circuit in parallel with each other. Thia 
gives a voltage of one-half what it would 
be if all were connected in series, and an 
amperage of one cell multiplied by the num- 
ber of groups. 

Mechanical OeneratoTB. 

A mechanical generator^ which is driven by 
the engine, produces a current of electrieity, 
and its action depends on " magneHsiu/ ' 
which is the property sometimes possessed 
by iron or steel, by which they attract other 
pieces of iron or steel, 

A generator consists of two parts; the 
* ' poles, '' * between which the magnetic field 
flows and the "armature, " which revolves in 
this magnetic field, and produces the current 
of electricity. (See fig. 4, chart 102.) 

The field is made in two ways; it is either 
a "permanent magnet,'' that is, steel that 
is magnetized so that Its magnetism does 
not change, or an "electro-magnetj *' that 
is, a coil of wire wound around a soft pieee 
of iron, which is a strong magnet only while 
electricity is flowing through the coO. 

•When the field is a permanent magnet 
(fig. 5 J chart 102), the generator is called a 
"magneto;'* when the field is an electro- 
magnet (fig. 4), the generator is called a 
"dynamo.'' (See chart 101 and 102,) 

The annature haa a core, consisting of 
soft iron, with insulated wire woand around 
it endways. There aro two types; a 
"drum*' type and a " shuttle*' type. Ths 
drum type could be revolved in either 
the "electro** or "permanent** magnetie 
field and would generate "direct** current. 
The "shuttle'* type is used only on genera- 
tors in which the magnetic field is produced 
by permanent magnets and always gener- 
ates "alternating*' current. (Will be ex* 
plained under magnetos further on.) 

The Toltage of a magneto or dynamo de- 
pends on the size and quantity of wire 
wound on the armature and field colls, and 
on the speed. 

Terminals: Mechanical generators usually 
have but one terminal, the other being 
"grounded," which wUl be explained. 
Where there are two terminals and "direef 

fWhcn Ihe poles of m itorAf* battnr Kr« not aurk»d tli« polarfly can b« deierratii«d by their n«tar»l 
'"' ' * " * ' •If armatrire t« 

oolor; the poiitive is darkvr^ ujually 
of the "ibuttle*' tn}*. 

brown color, wbei-eAi the nefitive it crur- 



torrent geaerators, ihej are marked as ilie 
terminala on a storage eell are nuuked. 
( -fpodtlver — negative.) 

Wlien UBlng "chemical" generatorsi sueli 
as a aiorage battery* the circuit is alio 
(quite often) grounded on one side. 

♦Gromulijig the Circuit. 

When the current of electricity ia re- 
quired to do work, as, for instance the pio- 
dttcing of a apark in the cylinder^ using a 
''make and break'* ignition system for es- 
Ample, it must be taken to the igniter 
Ikrough a coil, by means of a wire but 
tnay be returned to the generator by meaos 
of a ground/' Which la usually abbre* 
Tiated aa ''G" or GBNB and deaignated 
by a ai^ as shown in chart 109. See 
chart No. 102, fig. 7; and fig. 3, chart 
1(^3; dotted Hues show path of current 
through metal of engine. 

The frame and engine of an automobile 

are made of metal, and therefore will con- 
duct electricity. 

If the negative pole of the direct current 
generator is attached to the metal frame or 
engine, and a wire attached to the positiye 
pole, the current will fiow in the circuit 
when the positive wire is touched to any 
other metal part of the frame or engine^ for 
the metal acts as a conductor and permiti 
the current to return to the generator. 

Thia method saves wire, for wire is used 
only to take the current to where it ii 
needed^ the metal of the frame or engine 
bnngiiig it back again. 



When the current for the ignition is iup- 
plied by battery, it ia usual to have two 
Mta (^, Ij chart 103), and ia used to start 
the engine; after engine is started, tho dy- 
onmo or magneto supplies the current. The 
reason for this is due to the fact that a 
battery supplies a constant source of elec- 
trie supply, whereas a mechanical generator 
generates current only when running. 

A switch is placed in the circuit, so that 
either may be used. They are made in many 
forms, but a simple form is a flat piece 
of spring brass, pivoted at one end, so that 
it may awing from aide to side. The free 
end may touSh either of two knobs of brasa, 
one on each aidCi or be between them with^ 
out touching them. Each of the knobs are 
connected to one of the sets of batteries^ 
er one to the battery and the other to the 

dynamo, and the flat piece of brass is eon* 
nected to the ignition circuit. 

Thus when the free end of the switch ii 
swung to one side, or the other, it resta 
on one of the knobs, and the corresponding 
battery is thrown in circuit, furnishing the 
current for the ignition. 

When the switch ia between the knobs, it 
is out or **ofiF'^ of contact, and the circuit 
ia broken. Thus a swHch serves not only to 
connect either of the two sources of current, 
but also to break the circuit, which, of 
course, stops the engine. 

The switch lever can be detached from 
some makes of switches; when it is with- 
drawnj it breaks the circuit regardless of 
which side the switch is on. Thus only 
the holder of the lever may run the car. 

Ignition Systems. 

There are two syatema of ignition used 
for automobile engines; **low tension sya^ 
Im*' and the '*hlgh tension system;'* the 
source of electric supply being either by 
chemical means as: dry cells, or a storage 
battery, or mechanical means as: a magneto 
or dynamo (also called generator). (The 
Magneto ia explained further on,) 

The word "tension" means pressure or 
roltage; high tension being high voltage, 
asd low tension low voltage, 

Tlie low tension system of ignition is used 
am only a few makes of automobiles. The 
low tension system was formerly used to a 
great extent on boat eo glues and is still used 
to a great extent on stationary engines. 

The low tension system uses a low tension 
idngle wound primary coil as per fig. 7, chart 

102 and its source of electric supply can 
be a dry or storage battery, or dynamo. Low 
tension magnetos are also used, but the coil 
la wound on the armature (treated under 
*'Low Tension Magnetos.") 

The Mgh tension system of ignition is the 
approved ayatem now in use on very near 
all makes of cars. The high tension syetem 
may be either by a high tension coil and a 
battery; high tension coil and low tension 
magneto; high tension coH and dynamo in 
connection with a battery-^-or by a high 
tension "magneto" alone. 

In this Instruction and In number seven- 
teen, we deal only with coil ignition. Both 
low tension and high tension. Magnetos will 
be treated further on» 

, I or asfattre stdo can be grounded m ll m&kM no diffflr«Dca, Maiiiif»ctnrfri 

of Mandardising, »re grounding tb« peUttve pole of 0iorig« hatterj ( + ). 
3T5 — **iD«giifte iwitok" — Dot« twitch ii cloiod to itop Ignition. 


Tig, 1 — 8«ri09. Zincs co&iiect«d 
to c«rboa. 

OBiiZi oomrBcnriOK 

Ti$. I if the uaoal 
mctbod. Tbii mttb- 
od firei the volUfo 

of its CAUi ftOd Ad 

Amp«rmg« of one c«U. 

Fif . 2. Thii m«th- 
od flvea the TplUf« 
of but one cell uid 
•n ftmpermfd of lU 

Fff^, S ia • m«tli* 
od uifld for 

Tig. 2 — Pix&liet. Zincs con- 
nected togeth^f. CtrboQ connected 


gency. In tbii case the reader will suppose that tiro aaii 
of dry celfa aupply tbe cartent for ignitton; one aet la 
used for a wliile» tben tbe other; if both sets run down, then 
coonect them in njultiph &s showTi, This method ^iTea a 
cottage of five cells and ad amperage of two cells. 



Ftg. 8 — ^Multiple Berlea. See 
teJtt for explanation. 


Fig. 4 — A dynamo, 
tt mechaniul genera- 
tor of "direct*' cur- 
rent. Note tbe 
electro winding on 
field magnet. Tbe 
armature is *'drum" 


Fig, 6 — A niAgneio with ••per- 
manent'* mAgnet. If armature 
is "ahuttle" typo (see magnetos} 
the current will be ''alternating," 
if "drum" type, direct. 

rtlCA ^ TATION^RY J nOVABLE Switels, 

S«0W5 ft%T« <i9- 

wnt ot <»HtMAi»¥ ^w»m* -^ 

Fig* 6 — Explwiatlon of a Low Tension Prl- 
rnvx or Low Tension Coll (Single Wound.) 

By snapping the eftds of tiie copper wires 
connected with a b&tlcry (after winding this 
wire around a bundle of iron wires) a spark 
will be produced. The wires mast be "snap- 
ped" or eep&rated suddenly* and the current 
mutt pasa through the aioglewouad or pri- 
mary coil. 

rig^ 7 — A make and break low tension sjsIsb of 

The Igniter la shown, which makes and broaka 
the low tension current at it flows from the pott- 
live pole of the battery to the single- wound low 
lenision coil through twitch, tben to the miea tn- 
BUlnted ele(*trode, 

*Wben tbe nose of tlit cam strikes the tapptt 
rod, thia rod msk* s and breaks the flow of current 
And cre4fo« a flash or spark (as by hand, fig. 6). 
Tbt current flows from positive pole of battery 
to stationary electrode on engine, thence Uirongk 
movcAble elt-ctrode to metal of engine — thence by 
way of grounded circuit to battery. 

In the above illuBtratlon, the coU tlurougb wMek 
tbt current passes U a low tension coll, and the 
system of ienition is the "make and break" tyt 
tern. Either the dry cells, storage battery or the 
dynamo will supply the electricity- Either of thtat 
»ame sources of electricity would supply oleetrielty 
for the jump spark or high tension coil alao. Tbit 
(alter system will l»e treated further on» The mtg- 
nelu would require special connoctlona, if used, and 
will also be explained further on, 

Tbe spark tbonld occur just as pit ton it on lop 
of its stroke or slightly before. 

OHABT KO, 102 — Cell Oonnectiong. Mech&aic»l Generators. MaJce and Break Pdnclple of IgnlUon. 

*Jifoim tb& pcixAt do not remain together when not oparatlng — they are slightly apart. The cam or tappet ar^ 
rmogem^nt cmumBB tii¥ Mpmrk to "make" and suddenly "break," hence tbe torm ^*makt and break." 




Low Tension Ooil System of IgnlUon. 

If the ends of the wires of a primary or 
loT tension coil, are connected with a bat- 
tery or mechanical generator and connected 
together, the current will flow, and if then 
the ends are separated suddenly a spark will 
be formed between them. The more power- 
ful the current, the larger will be the spark. 
(See fig. 6, chart 102, this illustration ex- 
plains the fundamental principle of coil ig^ 
nildon, therefore study it carefully.) 

The Make-and-Break Low Tension Ooil 
Ignition System. 
This system is shown on page 214, fig. 
7 and also page 216. 

ttThe "movable electrode" is opermted by e 
cam emngement. exactly ai the exhaust TaWe of 
the engine is operated. As the spark is needed 
only once daring two revolutions of the crank 
ahaft, the cam is attached to the half-time 
shaft, and operates the electrode by a rod called 
a tappet. 

The "stationary electrode" is insulated from 
the cylinder with mica, and one wire of the cir- 
cuit is connected to it. Tlie "movable electrode" 
ia operated by a cam, which is in contact with 
the current from the groonded wire of the bat- 
tery and which allows the current to pass from it 
to the metal of the cylinder. 

When the two points are in contact, the cur- 
rent flows from the positive pole of the battery 
by a wire to the stationary electrode, then to the 
Borable, because the two are in contact, and back 
to the battery by the ground. 

When the two electrodes are separated by the 
earn acting on the movable one, the circuit is 
broken, and a spark formed between them. 

Illustration flg. 1, page 216, shows the make- 
and-break system with two sets of batteries con- 
nected to the switch in such a manner that either 
•et may be used. 

While any battery would give a spark, a 
strong one is needed to ignite the charge sud- 
denly and completely, and to do this it is neces- 
sary to use a strong current. Therefore several 
cells are connected together, usually 5 or 6. One 
set is used a while then the other. Dynamos, 
storage batteries and low tension magnetos are also 

fWipe Spark Low Tension Ooil Ignition 

Wipe spark ignition is similar to the "Make 
and Break" in every respect, except that it 
makes a wiping and rotary motion as the elec- 
trode (A) of the igniter revolves; being operated 
"by an eccentric rod (E) from the cam gear. 

The other electrode (B) is stationary and 
looks very much like a spark plug. This type 
of ignition is never used on the automobile; 
but is here shown so that the reader can master 
the elementary principles of the different igni- 
tion systems. This system is used mostly on 
itationary engines. 

The Low Tension OoiL 

We have learned the different sources 
from which electricity can be obtained for 
ignition. Also the first principle of ignition, 
which is the old style "make and break" 
igniter using a low tension or primary coil. 
This system is seldom used, only on sta- 
tionary engines, however, it will be well for 
the reader to master the principle of the 
low tension coil, as it is the foundation for 
tending up a high tension coil or magneto 
annatnre winding. (See fig. 6.) 

vfll W wnttmA. Th* vinT mut W "caap- 
Smk fan tkraask Om slagla^voaBS ar pri 

The current is strengthened, or intensified, 
by the use of a simple coil, called a primary 
or low tensioii oolL 

. Oonstnictlon: Consists of a bundle of soft 
iron wires, called the "core," around which 

is wound several layers of well-insulated 
copper wire. (See also coils in chart 103.) 

A current of electricity passing through 
the wire will make the core a magnet, the 
magnetism ceasing as soon as the current 
stops flowing. The magnetism of the core 
'acts on the current of electricity, and in- 
tensifies it, and making it strong enough to 
produce a good spark between the electrodes. 

The reason for the current being intensi- 
fied requires an understanding of electrical 
engineering to make it clear; it is sufficient 
for the repairman to understand that the 
current is intensified. 

The positive wire of the battery leads to 
one terminal of the wire wound around the 
core of the coil, and the other terminal of 
the coil winding is connected to the sta- 
tionary electrode. 

Because the action of the cam moves the 
movable electrode, it can be seen that mak- 
ing the cam operate sooner or later will 
make the spark occur sooner or later. The 
cam is therefore arranged so that it may act 
sooner or later on the tappet and electrode, 
and is controlled by a lever, so that it can 
be advanced or retarded just as a timer on a 
high tension coil system.! 

ttThe low tension **makd and break" ignition system: two metal points (electrodes, flg. 7, chart 
lOS) are set in the combustion space of the cylinder, one of them being stationary, and the other 
■Movable, so that it may touch the other or be separated from it. 

The tvo points are called "electrodes,** and form what is termed, the igniter. The two points 
ava eonnaeted in the ignition eireuit, so that when they touch the current passes from one to the 
■tier. Mid whan they are aeparated a spark is formed between them. 

tTha aMfea and break ayttem is seldom used on automobiles. Used more on ataWouarr «nl^B'aa. 
^ 'HHsA «Mfi^* li sfmHar; also naed on stationary engines, see aboTe, and **I>yke*a HoVn lL«iiui\.^^ 



FIG, I MAK£ A/^DBf?£Aff Sr5r£M0fi 

/m/rwM i/i/^r// d/TY ceLL% 2 5£n, 

fioa mH£ hNO Bf(tKHJbNmoN 

w/m 3rom(j£ batt£Ry 

low T£NStON 

F/c.H. mK£ AmB^Aff. w/r// 
no 5. mjf£ Amm£Aff. w/r^ mr c^m m7re/rr705TA/^z anomaca/^to to ffuM 

W 5rAlfT ON, ANO OYA/AMQ 70 fWN OfJ, ^^ ' 



TO r?(/u ON. 

ff6.G, 3rAr/0N4/rr £^A/(f/Af£ 
writ, oRY ctLli> TV 5rAffr OAf^ 


CtHAST NO. lOS^-Dlagrams of Wiling far tbe I^ow Tension ''Make and Break** System of 
IgnltAon u^nz Dry CeUs or Storage Batteries (chemical source), and Dynamo or Magno- 
tQ (mechsmicBl source)* 

wiling DiagTuns of the I«aw TenBion 
Break*' Ignltioii SystesL 



▲ "make and break" system (see chart 
H>8>; requires less care in wiring than the 
blgk tension or jnmp spark system, but is 
not suitable for high speed automobile en- 

The first difficulties were; insulating the 
ftationary spark pointy and making an easj 
working but tight joint for the moving 
spark point, although this has been largely 
overeome^ the jump spark or high tension^ 
has proven a superior ignition and it is 
to this latter system we will confine our 
attention in the following instrnetSoiit* 
It is wellj however, for the reader to mas- 
ter the low tension system of ignition In 
order to understand the high tension sys- 

Wiring for two sets of dry cell batteriee: 
la Hg. 1, chart 103, we have two sets of 
dry cells as the source of electricity for 
the make and break system of ignition. 
One set is used a while and then the other. 
Dry cells run down rapidly, therefore this 
^stem is seldom used. 

Winng for baUeries to start oa aod the 
dynamo to run on: The dynamo^ which 
generates a direct flow of electric current, 
is usually placed so that it is operated by 
the engine, and the usual plan is to start 
the engine with dry cells, and after engine 
is started, the dry eeEe» are switched off 
and the dynamo supplies the electric cur- 
rent. (See fig. 3.) This system is used 
quite extensively on stationary gasoline 
engines, as well as a great number of marine 

Tlie storage battery for make and break 
Ignition: This system (see flg. 2), is pra^* 
tical if the storage battery can be re- 
charged. The storage battery will supply 
a certain quantity of current for a certain 
period of time; for instance, suppose the 
storage battery was a 60 ampere hour bat- 
tery, and the ignition system used one am- 
pere of current per hour; in this way we 
would have a sufficient quantity of electric- 
ity from the storage battery to run the 
igxition for 60 actual hours. 

Suppose the engine only runs three hours 
per day — we would use three amperes of 
the 60 in one day; therefore we would 
have 57 amperes left, which would run 19 
more days of three hours per day. 

The storage battery delivers the same 
pressure until all the amperage or quantity 
is gone^ whereas a dry ceH, not only loses in 

amperes or quantity, but it loses its pres* 
sure in a very sh^rt time of service. 

The usual pressure required to force the 
current through the coil is six volts (pres- 
sure). The storage battery will hold this 
pressure until the quantity of current is all 
gone. The dry cell drops in voltage rap- 
idly, and therefore weakens the spark. 
When a storage battery runs out, it is re- 
stored with electricity. When a dry cell 
runs out of current, it is thrown away- 

Sometimes we see a storage battery and a 
dynamo or magneto connected so that tlie 
engine is started from tlie storage battery 
and then switched to the dynamoi after the 
engine is running. When a dynamo or 
magneto is used for supplying electricity, it 
is usual to have either a set of dry cells, or 
a storage battery to start with. The rea- 
son for this is; a dynamo or magneto must 
first run in order to generate electric cur* 
rent, and the usual plan of cranking an en- 
gine will not speed up the dynamo or mag- 
neto fast enough so that it will generate 
current. Therefore, the dry cell and stor- 
age battery are used for starting, and after 
the engine is started and is running fast 
enough for the dynamo to generate current, 
the switch is thrown from the battery to 
the djnamo. 

A low tension magneto for ignition: The 
subject of magnetos (low and high tension) 
is treated under a separate instruction. 

The low tension magneto is used quite ex- 
tensively for make and break systems of 
ignition, in connection with a set of dry 
cells to start with, on the same principle as 
the dynamo combination. The magneto, 
however, differs from the dynamo* in that 
it supplies an '^alternating" current instead 
of a ''direct*' current. 

No coil is necessary in connection with 
the low tension magneto, but the coil in the 
diagram (fig. 4) is used in connection with 
the battery for starting. The coil used with 
the magneto is wound on the armature of 
the magneto. This subject will be treated 
further on. 

A four-cylinder make and break system 
of Ignition with d^ cells and dynamo. All 
of the diagrams shown are illustrated on 
one-cylinder engines. In fig, 5, chart 103, 
a four-cylinder engine, with make and break 
system of ignition, is connected up, using 
a corabination of dry cells to start with, 
and a dynamo to run on. 

*.v.« — The above iyttenu sre not now na»d on tiitoinobllfls, but w#r« formerly tijed in the 
•srly dmyt of motoring. The resaon for explalntBg the old iyatomi of ignltioii, la duo to the feci 
Ulii l^e nndertjinir principlea of the more modern ftyatema are foauded upon the prmciplea oi ««*■ 
esifly d*yi. Therefore it is esfenUnl thet tbey be maatered flrat in order to more clearly nndertteiid 
Ihm n«dero lyateroa treeted fBrtber oo. 





S^COmARY m/?£ 

?£ TO 5PARK PL ua ^CORB. 


Fl2. 1. — ^An exaggerated drawing, made for the purpose of lUnitratliif how the spark ptng Is aci efwed 
Into toe eomhustlon chamber of the engine, and how the cnrrent Is oazned ftom the baltirj thrvigh the 
primary winding of the eoil, to commutator, ete. Also showing the secondary drcait The lower second- 
ary wire cooldbe connected to the primary wire instead of grounding to engine and the path would be 
through metal part of engine, through commutator roller back to coil. See page 226. Trace the 
circuit with your pencil. 

wtm » asi 

fig. S— Farti of a mica Insulated spark plug. 
Tb« ail«a phig construction is explained on 
2%n, ng. 13. The porcelain type is used 


ng. 3 — ^Parti of a pefiwlatii t a m la t ed spark plur 
seperated. Spaik pings are used with Jump spark eeU 
and high tension sttgnoto ignition systems. See a 
pages 84, 286. 288. 

8 — iron shell which MNtwa into engine. 
H— brass bushing wideh haUr (O) In 
O— porcelain wHh a l e rti aia CT). 
T— rod, ealled < 

a (T) I 

CMAMJ MO. 104— DlAgram Showing the Parts of a High 
MfrMma tuiag m High Tension OoU (with vibrator) aaa 
^M^/* ping Im anamUr ptmeed orer the inlet TaWe; See footMle 





tbe aparkjumpa the gap 

s\v sw 

^ . . . . .s. 




Low tension High tension 


Fig. 1 — Anoibflsr ^ew of » JtLm^ npmik colL, also cilled ui induction coll, Mgli t«iuiion cott •! 
■•coiidftzy coU. The il]u«trfttion explains liow the primary And eecoiidnrj windiug U wrapped ovtr 
the core and how the ma^oetic vibrator mtermpli (he flo'pr of electricity from battery ikroiich Ilia 
primary wire circuit, aod how the spark ju^mpi th« "gap" of the ipark plug. WhaE iwitcli (or timar) U 
clo»«d, the current i3owB from battery through tbii primary wire wrapped around the core or busdla 
of iron wires (A), (trace with peucil). The buudlo of iron wirea become oaagaetited wheH the primary 
etectrk current flowi arould it. This magnetlim camiea the vibrator blada (0) to ba drawn away 
from ita connection with screw (F) at platinum poinii (P), 

Tho moment this vibrator is drawn away frcm screw (F) the circait is broken and the bundla 
of wires (A) loses its magnetism^ therefore the vibrator (C) is again drawn back to screw (F) by 
■pring (8), but the moment the ccntact is again made — (A) afain becomes magnetised and draws 
the vibrator (0), This is repeatefl eo fast the vibrator (0) limply busses. The greater the buxs, 
the greater tho spark or voltage and more current consumed. 

When this vibration takea place the current is "Isiucad** in the aeoondary winding (wrapped 
ovar the primary winding) by ''indactio'n" and thia induced curregl is intensified, that is, the praa- 
sure is raised to such a hi^h voltage it will Jump the gap as showu, or if one end of this secondary 
winding (SW) ii connected to a spark plug and other end grounded, then it will jump the spark plug gap. 

A timer is used instead of a Bwit<;b bat Hi purpose is the same, see page 222. 

A coiideDJ«r is connected or '^shunted" around ihe poinU (P) for porpoie explained on pigai 
nS and 229. 


MTTACH£0 TO SP^et^ L£y£it 


\ ^ 




ng. 2— A Mechanical Vibrator. 
(Seldom used.) 

The purpose of this device is to open and close 
the primary electric circuit in rapid succession 
mechanically, instead of the magnetic vibrator. 

When this type of vibrator ia used the vibrator 
on coil ia not necessary as shown in figs. 8 and 1. 

The case is made of fibre or metal, but the 
spring and screw are tnsxilsted from each other. 

The above timer is nsed principally on aingle 
cylinder motorcycle engines. 

rif , S--A Magnetic Typo of Vibrator. 
(Same as on coil in fig. 1.) 

Thia Illustration ahows a vibrator placed o» 
the CO Li and operated electrically. 

There must now be a "com mutator*' or timer 
to cloae and open the circuit at the proper time* 
In order to operate thia vibrator electricatly. If 
aagiiie it a four cylinder engine, a commutator 
with four contacts, as shown on page 222 would 
be required. 

CHAB^T NO. 105 — Diftgram expljOnlBg tho double wound Hl^li Tension OoU and Action of Uw 
Vibrator, Yh» Mechanical Vibrator and the Electrical Vibrator (vibrators are some timet 
emlled "tremblers,'*) 


Elementary Frfuciple 
Tlie r«ason for this separate current flow- 
lag In tJie ''secondary*' winding can only 
be understood after studying electrical en- 
gineering; however, we will endeavor to give 
Uie reader the elementary principle of 
<< magnetism," ** lines of force'' and *'in* 
doced*' current, also the relation of volts 
and amperes to cell connectionB, as fol- 

In order to pftoduce a spark In the cylin- 
der of engine sufficiently strong to ignite 
the compressed gas, it is necessary to have 
the •current producing the spark under 
great pressure* The pressure or voltage of 
a storage battery or a number of dry cells 
ij not enough, so it remaina to make this 
pressure greater so that it may be used with 
good results. 

Baising the voltage of the battery cur- 
tent is accomplished by means of an indue* 
ties ooil (high tension coil) calJed a spark 
eolL In order to fully underetand the in- 
duction coU, a few elementary steps must 
be learned first. 

An ordinary horseshoe magnet Is known 
to attract iron and steel. The magnet will 
have a holding effect on the iron or steel 
eyen if the magnet is separated from the 
Iron by a piece of paper or glass. The mag* 
net attracts the iron because of some mys- 
teriouSy unseen force that is called mag 
netiam. We cannot see the roagnetiam, nor 
emn we feel it, but we can see and feel the 
effects of it. If a number of iron filings 
are attracted by a magnet , it will be noticed 
tkat the flings arrange themselves in rows 
from one pole of the magnet, to the other, t 
It la cuppoied that the filings arrange them- 
■eWee in lines because the magnetism goes 
from pole to pole, or end to end, in lines. 
We cannot see these lines, but their peculiar 
eharacteristica has resulted in their being 
eaUod "lines of force." 

In other words, that unseen, mysterious 
force which we call magnetism is erpressed 
in ''Unas of force.'* All the lines of force 
between the two poles of the magnet com- 
prise a ** magnetic field/* 

Now, the magnetism or *' magnetic lines 
of force" manifest themselves not only 
around a magnet, but around any current 
carrying wire. This can very easily be 
proven. In fig. 1, a battery is being ex- 
kauated through a conductor. If a compass 
if held near the wire shown, the needle 
of the compass will suddenly take a turn 
and then remain stUL The current passing 
through the wire causes magnetism to exist 
ironnd the wire for a certain distance, and 
thia magnetism, acting upon the steel needle 
of tlie compass, causes it to turn. 

If this simple experiment is tried It will 
b« found that the compass needle will turn 
••In the direction of the flow of "lines of 
force'' around the conductor. The cur- 
rent in the wire flows from the carbon or 

of a High Tension ColL 

positive aide and in the direction shown by 
the arrow. It should be borne in mind^ then, 
that around every conductor of electricity 
there are lines of "magnetic forco" or, as 
we shall call it, a "magnetic field." 

Tke magnetism from tbe magnet is called 
"natural magnetism.*- But magnetism may 
be produced in another way by the use of 
what is called an "electromagnet.*' The 
apparatus is shown in ftg. 2, An Iron bar 
has packed around it some paper or Other 
insulating material. A coil of copper wire 
is slipped over the iron, which is called the 
core. The two ends of the coil or wire are 
attached to a number of dry cells, con- 
nected in aerlM. 

If a p 1 e e < 
of metfikl sueh 
as steel Is 
placed near 
the end of the 
core it will bs 
attracted b y 
the core. If 
the wires from 
the battery wt§ 
removed th c 
pieces of iron 
or steel at the 
end of the core, 
are no longer 

In o t b e I 
wordSi as soon 
as a current is 
passed through 
the copper coil, 
the iron core 
IB magnetized, 
but as soon 
&8 the current 
stops flowing 
the magnetism 
stops. We do 
not know why 
the core be- 
comes a mag- 
net, except it 
be by the 
presence of a 
magnetic field 
around the eop- 
Fi^. 1. Not* there 1» mm^- per coil. Thii 
netlim ev«a in b copper wire jjjaKUetic field 
If connected to « tource of 7* ^ ^^„ 

electric tupply. p 1 e r c e s any 

Fif. 2. A primary uingltt thing. This is 
winding of copper wire (ni- here evident be* 
nmllj of Imrser lite than the ^^e cort 

■e4M>Dd winding), around « v».iow , 

toft bmr of iron wiJJ efta»e is insulated by 
bftT to become roairnetbsd. paper. It could 
Fi^. 3. If ADother windinit just as well 
(»m»ller wire), U wrapped u-^- been 
aroand the primary, a higH ^^^^^ " * f^J; 
tention cnrrent of electricity wood or giass 
will be *' induced** into the or stone, 
tecond winding. ^^ ^^^ .^^ 

been shown that the current flowing 
through a coU of wire affects an iron 
bar within it so as to make the bar be- 

'Cnrront** me&ni electricity or the flow of electricity, 
♦' Thn wgh an error, compaaa needle la if. 1, is ihown parallel to cnrrent flow. lntt«%d q1 \\ik%% ^ 
' needle ahonld point towards you« fSee page 2(17. 




Fif. 1 — Simple form 
bnish type of Tommntator. 

Tig. 1 — ^The reyoWing part is fibre (insulation). The bUck part is 
a metal strip or segment grounded to cam shaft, nie blade or 
bmah is insulated from the base. This brush oonntett with 
primary winding of coil, thence to battery and one end of battery is 
grounded. When the segment touches the brush, the contact is 
completed and cftuses the ribrator to ribrate. 

Fig. 8 — ^The principle is the same as in Fig. 1, except a roller 
makes the contact with segmentsf Bach segment is connected with 
the primary winding of coil. There are as many segments and coils 
aa there are cylinders. 

Fig. 8— This ^pe of timer is used in connection with a coil with- 
mii of Tibrator. It makes a single hot spark as explained 

There are as many cams as there are cylinders. On 
the ah9f% there are four cams. Therefore, it is suitable for a 
foto eyllnder engine. The abore timer is the Delco. 




fig, 2 — Roller type of 
cootA^t eom mutator (four 
tylinder tfpe as an exam- 
ple J, 

Fig. 8 — ^The modern 
type of timer. 

Fig. 6 — Note the manual (hand) method of ''adTaneing" and "retarding'' the commutator. (Four 
oyllader engine as example.) If the roller is revoWing to the right, by shifting the commutator housing 
to the left, contact woulfl be made earlier — this would be called " adTaneing" the spark. If shifted to 
the right, would be made later — called ''retarding." 

Wkaa ualBg a Tibrator coil (which is the case here), the time of spark is set earlier than when using 
the ai^le apark system — ^because plenty of * time must be giTon the spark to Ignite the gas so it will ignite 
•r ««Mutt on top of the stroke instead of after the top. Noto connections to commuUtor for firing order 
•f !♦ 8, 4. a.) 

HO. 106— »• OouBiitatoi; Timn and Pinpote of 

' it* t, la apwk^elrtmit type. The dOMd-elrenil type 

CkW MMiU tor OontroL 
pagM 84S and 878 is now in general 


eome a magnet. Jt will also affect an- done in fig. 3). The construction is just 
other wire placed alongside of the wire the same as if we took the electro-magnet 
uurrying the current. These same lines of referred to in Fig. 2 and wound the second- 
force which will make a«magnet out of a ary coil outside of the primary coil. 
piece of soft iron will set up another cur- The secondary current acts in the same 
rent of electricity in another wire close to manner as the prilnary current; that is, it 
ity but which has no electrical connection flows through wires and can be made to do 
'^th it. work, and it can be grounded; the current 
That ia, if we would take a coil of wire leaving the secondary winding at one term- 
and attach the end of the coU to a battery i»al ^^ returning to the other. The dif- 
and then wind another coil around this first f erence is that it has exceedingly high pres- 
one and insulate it from the first, we would s«re (voltage), and little volume (amper- 
find that every time the current in the first age), and flows in a reverse direction, while 
coil, that is, the one connected with the bat- the primary current has low pressure and 
tery and which is called the primary coil great volume, but in both cases the total 
is interrupted, or commences to flow or stops currents are equal. 

flowing, there is a current set up or "in- Therefore we have learned the first inrin- 

daoed' ' in the other coil, which is called the dples of a high tension coil; how the iron 

"aeoondaxy" winding. core is wound with a ''primary" wire, and 

A. long as the current in the first coil ^Lred'tL'^-s'eto^dS^'fs wound' "^'""^ 

continues without change or interruption, it *^^^®^ ^^® seconaaiy, is wouna. 
does not set up an "induced" current in When the circuit of the primary coil, which 

the secondary coil, fig. 3. ^s connected with a source of electric supply 

of some sort, is closed and opened suddenly, 

Tha enzrent Is "indncad" in the second- the current is "induced" in the second 
azy ooil only irhen the flow of cnirent in winding, and at the same time it is "in- 
tlM piimary coil changea, usually by open- tensified," meaning, the voltage is raised 
iiig or dosing the circuit. The effect of the so high it will jump a gap as shown in 
primary coil upon the secondary has been figure 3. The method for making and break- 
found to be increased if we put a bar of Ing this contact at the right time, wiU now 
aoft' iron inside the two coUs (which is be treated. 

The Vibrator — ^Its purpose. 

As the secondary current only fiows when the primary current begins to flow, and is 
mddenly interrupted, there must be an arrangement that completes the primary circuit, 
0o that the battery current stopf flowing or is interrupted from flowing. 

This arrangement is called a "vibrator," and it may operate in two different ways; 
"electzlcaUy or magnetically," and "mechanically." 

The Mechanical Vibrator. 

The "mechanical vibrator," is shown in chart 105, fig. 2. When this type of vibrator 
is need, the TlMrator on the ooil Is not reqnlred, as the vibration of the fiat spring againtft 
the adjusting screw causes the contact to be suddenly opened and closed, by the cam, 
during which time the flat qirlng vibrates mechanically, causing an induced current to 
flow in the secondary winding of the coil. 

It consists of a flat spring with a small weight on one end, and the other 
end is attached to a post. The weight rests on the iron rim of a small cam 
with a notch in it, so that when it turns the weight drops into the notch. One wire 
from the primary circuit is attached to the flat spring and the other wire of the 
primary to an "adjusting screw." 

When the weight called the bob, is in the notch of the cam, the float spring 
makes contact with the "adjusting screw," and the current flows, but the cam in 
continuing to tupi moves the weight out of the notch, which separates the flat spring 
from the screw, and breaks the circuit. 

Becausa of the springiness of the flat spring, it vibrates when the weight drops 
into the notch, making and breaking the current. By making and breaking the con- 
tact in this way, the primary current flows through the primary winding in waves, flowing 
and stopping each^time that the vibrator makes and breaks the circuit, which produces 
a corresponding current in the secondary winding, called an "induced" current, as 
previously explained. 

The i nt e grity li on method flg. 2, chart 105, was used extensively on single cylln- 
der motoicyclo enginaa and a modlflcation of this principle Is nsed on the modem 
ignition syatams^ as the Delco and Atwater-Kent systems, but instead of the flat 
wptbkgf a different method is employed as shown in fig. 3 chart 106, which gives but a 
singia spark* The principle of "mechanically" closing and opening the circuit, how- 
9wm, la atailar. (See also pages 247 to 252 and 378.) 




Fig. 1. — One Ofllndei IBnglne witli ft Vibrator Type of Jump Spuk OoU ftcd Two SatJ of Bry 
BftttorlM fa; Ifultlon. Qui? otie set of batterieft in uia %l th? tinie, ComBiuUtor r«valvefl one- half 
the spe^d of crsnk shift. 


Fig, 2.-^Tifo Cyllndar VeittetJ Eiifiii« (ISO d«|r«e cr»nk ibmft} with » Vlbrmlor Typ* of Jtimp 
Spftrlc OoU and Two S«t» of Dx; Oalis fof Igiiiti<^ii. Kote poiltion of se^meDU on cammaUtar. 
titor rtevolves ODe-ball tbe speed of crank sbftft. (,ThU type of eagino ii t^ldom ueed.) 


Fig. 3.—A Two Oylindef Opposed Typo of Engine 
with ft Two Drlinder Jump Spark OoU and a Set of 
Dry OoU* »o» • Storage Baltery, either of whkh 
may be osed. The t*o eoptacU on commutator 
placed opposite. EeTOlvei ^ ap«*d of crank abaft. 

Tig, ft, — A SlDfla Cyllader Vibrator 
^7P% Of Jtimp Spark OoU. Tbia type 
ii uiually called a **Box Coil.'' Quite 
frequenlly a aingle eyUnd«r box coil 
hai but OQt aeeoadary «on section ou 
lop. la. tbia caat the secondary eon- 
n action ahowo at front of th« coil ia 
eoonett«d ioaide of tba coil to tba prl* 
mary wire which cbnnoeta to bindlog 

pOftt P. 

0EABT HO. 107— Wiring Oonnectioiis of tHe BlgH 
(MBgoetOB not «hown here). 

Ylbnttor OolJ System of IgnitioiL 


The Magnetic Vibrator. 

The magnotic vibrator depends on the magnetism produced in. the core of the 
i when the primary current passes. (See figs. 1 and 3, chart 105.) A flat spring, 
ealled the vibrator spring or blade, is so placed that one end of it is opposite the end 
of the core, the other end being firmly supported. Touching the vibrator spring near its 
free end is the i>oint of contact with the "adjusting screw.'' 

Ocmnections: One terminal of the battery (fig. 1, chart 104), is attached to the 
adjnsting screw; the vibrator spring is connected to one of the primary winding of the 
eoll; the other end of the primary winding is connected to the conunutator, which we 
win eaU a revolving switch. When the "commutator" switches the current through 
the piimary winding the "core" becomes a magnet and attracts the ft'ee end of the 
vibrator spring, drawing it away from the adjusting screw. As soon as the attraction 
drmws the vibrator spring out of contact with the adjusting, screw, the circuit is 
broken; the current stops flowing ifti the primary coil, the core ceases to be a magnet, 
and the vibrator spring being no longer attracted by the magnetism, it springs baek 
and again makes contact with the adjusting screw. This again doses the circuit, the 
vibrator spring is again attracted by the magnetism — thus the circuit through the 
vibrator spring and adjusting screw is broken and made again as long as the commutator 
the primary circuit closed through its contacts. 

The strength of the secondary current, and consequently the strength of the 
■park, depends on the correct adjustment of the vibrator faring by the adjusting screw 
Afl the construction of a coil is very delicate, it is not expected of the driver that he be a 
eoil expert, but he should know how to adjust the vibrator properly. 

Succession and Single Spark.* 

The high tension coil using a magnetic vibrator in connection with a commutator 
{Hg, 1, chart 104); causes a "succession" of sparks instead of a "single" spark. 
The disadvantage of this type of coil is the possibility of the vibrator platinum points 
stieking, consequently a missing of explosions. Another disadvantage is thiat it 
makes several weak sparks, the hottest one igniting the charge. This causes slow ignition. 
A good "single" hot spark has proven the most eflfective, as used on the Deko and 
Atwater-Kent systems, employing a mechanical type of vibrator; (flg. 3, chart 106 and 
page til). 

The Commutator. 

Because the secondary current is only needed when it is time for the 
spark to pass and ignite mixture, the primary current is switched into 
the primary winding only once during two revolutions, (on a single cylinder 
engine), and the switching is done by a ** commutator" or ** timer." 

Before proceeding further we will make a distinction between a commu- 
tator and a timer. Heretofore the word ''timer" and ''commutator" have 
been used to apply to the same device. Suppose we call the device which 
makes the contact by a brush or roller contact, as per figs. 1, 2 and 6, chart 
106, a commutator. This device is always used in connection with a mag- 
netic vibrator type of coil. 

The Timer. 

The timer, we will class as a mechanical method of causing the contact 
to be elosed and opened, as per fig. 3, chart 106. This device makes a single 
spark and is generally used in connection with a coil without a vibrator. 

There are two principles of the timer; one, where it is used to open the 
eireoit which is otherwise always closed. This operates on what is termed the 
dOMd cfarcait principle. The opening of the closed circuit interrupts the flow — 
therefore it is termed "an interrupter" or "contact breaker," (see page 243). 

The other, when it is used to close the circuit which is otherwise always open. 
Thia operates on what is termed the open circuit principle: (treated further 



^mmAttr j^M^jTS FMfi.^ fa ept*'^ 



Circuit of a Four Cylinder Vibrator Coil Ignition System Dsing a Commutator and Two 

Sets of Batteries. 

This illustration explains the primary wir- 
ing connection from the battery, through one 
of the coils and connections to the other 
three coils and to the commutator, back to 
battery. Also the secondary circuit from 
coil tu spark plugs back to coil. 

Primary Circuit: Place your pencil on the 
drawing at the (P + ) positive pole of No. 1 
battery and follow out the circuit. 

We will begin with the poaitiTe pole con- 
nection of Kg. 1 battery; there are two sets 
of batteries, but only one set used at the time. 
If one runs down, the other one is thrown into 
service by switch on the coil. The switch is 
now on No. 1 contact and the circuit is from 
No. 1 battery to switch, through switch lever 
to bus-bar on front of the coil, which connects 
to the contact screw **V*' of coil, thence 
through the platinum points, through the 
magnetic vibrator spring, to the primary 
winding which is wrapped around a core or 
bundle of soft iron wires. 

The other end of this primary wire of coil 
connects with the segment on' the commuta- 
tor; the current is closed here at the proper 
time. The commutator roller contact revolves 
as explained previously. When this contact 
is completed the primary circuit is closed on 
one of the four coils, (it is now closed on No. 
1 coil). When this circuit is closed, the 
bundle of iron wires (core) becomes magnetic 
and draws the vibrator down, but the moment 
the vibrator is drawn away from the contact 
with the vibrator screw, the circuit is broken 
and the vibrator springs back and makes con- 
tact again, but is immediately drawn down 

again; this, of course, is quick and rapid. 
This vibration is kept up as long as the con- 
tact is made on the timer, which, of course, is 
only for a moment, but during that time the 
vibrator makes several vibrations or * * buzzes ' ' 
as explained on page 220. 

Secondary circuit: When these vibrations 
occur, the current is ** induced" into the 
secondary winding of fine insulated wire 
wrapped around the primary winding of coil, 
called a "secondary winding." (How and 
why this current is induced into the secondary 
winding without any metallic connection wifs 
treated on page 221.) 

This secondary winding, of course, has 
two ends; one end goes to a spark plug and 
the other end connects to one side of the 
primary wire, which grounds it through the 
commutator roller to engine, when roller 
makes contact, thence the circuit is to metal 
shell of spark plug in engine, across the 
spark plug gap, to the insulated part of 
spark plug, back to coil — see also page 218. 
A seperate coil unit is provided for each 

The duty of the commutator is to make 
contact at a certain time in order that tiie 
right coil will operate and supply an electric 
spark to the right cylinder at the right time. 

When on« wlrt on any wiring diagram passes 
ov«r another wire withont making contact, a half 
circle is made, as shown above. 

OHABT KO. 108 — Explanation of how a Four Cylinder Engine is Operated by Four Vibrator Coil 
Units, Commutator and two Sets of Batteries. Note the firing order is 1, 3, 4, 2. This 
change is made on the commutator. 
S^e pM/pe 356 tor electrhal aignn or symbols — of wires crossing, etc. 



tA commutator might be termed a revolv- 
ing switch whieh brings two pieces of metal, 
^nnocted in the primary circuit in contact 
with each other as it revolves. One part of 
tilt commutator is stationary and the other 
movable, being attached to the half-time 
•haft (cam shaft). The usual location for 
a commutator on an engine, is on the end 
of the cam shaft, as shown in chart 106, 
flg. 6. (Also see Ford supplement.) 

Oozkatmctlon: Commutators are made in 
various forms, some of which are shown la 
•hart 1(>6* (It is now seldom used.) The 
aimpleet, being one shown in fig* l^ con- 
lists of a small disk of hard rubber, wood 

i flbre, or other insulator, in which is set a 
piece of metal that makes contact with the 
•haft to which the disk is attached. A flat 
metal 0pring, called a brush or blade rests 

[ on the circumference of the disk, and as it 
tarns the metal plate is brought in contact 
with the spring. 

Chie wire from the primmry circuH i» con- 

[aeeled to tho bmah : the ihjift being of roctaU And 

nMtinif in isptal bearings, ia in contact with the 

■l«tal of the en^tQe and contequently the electric 

onrreat may pan from it to tlie primary wire 

^ tiial is groanded on the en^oe. Tliua when the 

%m1 has turned eo that the piece of metal called 

MMitect, malceii connection with the bntsh (the 

or blftde being ininlated from the baie>» 

hm ovrrest paciea from the brush to the contact. 

• tfie abaft, and then through the metal of the 

lea^a* back to the battery. At the wheel in con- 

ribiQing to turn movea the contaet away from tho 

^^ruah, ibe eircuit ii broken and the current 

Bich time that the contact touchei the bmnfa 
sr bUdOi the battery current pasies through the 
priiaanr irinding of the coil, making the ribrator 
op«ra(e and cauaing the secondary current to 
f«m ita apark in the cylinder. 

Oommntator segments; The metal contacts 
^Ib the fibre housing (fig, 2), to which wiree 
coils are connected, are called **8eg- 
•enta." There are as many segments as 
Ithere are cylinders. These segments are 
rplaeed certain distances apart according to 
[be aumber of cylinders, for instance; a 
•*two cylinder*' commutator would have 
two contacts; if it is of the opposed cylin- 
der type. The two contacts would be placed 
ISO degrees apart. If a "single cylinder" 
engine, only one spark is necessary during 
two revolutions of the crank shaft, therefore 
the contact roller would revolve one-half the 
of the crankshaft and there would 
be but one contact segment* 

If a "foiu- cyUcdei * «ngine» there would bo 
feiff contacts; ptaced 00 degrees apart. Because 

the eoEtact roller revolves one -ha If the ap'aed of 
the crank shaft, there would be four sparks during 
two revolutions of the crank. If a 'Hhree cylin- 
der** engine, the contacts would be 120 degrees 
apart. The roHer contact also revolves one-half 
the speed of crankshaft iu this instance. If a 
*'tiz cylinder" eogrlne the contacta woald be 00 
degreea apart, aa six impulses or contacts are 
necessary during two revolutions of the erank 
Bhafti therefore the roller contact would revolve 
one-half the speed of the crank shaft also. On en 
*' eight," the contacts would be 45 degrees apart. 

How the Commutator or Timer ^ 
Helps Control the Speed. 
The commutator *iB connected to tlie 
spark lever on the steering wheel* (See 
fig. 6, chart 106.) When the spark lever is 
pushed forward the commutator is shifted 
forward so that the metal roller makes con- 
tact earlier with the contact segment — this 
is called '* advancing*' the spark. 

If the commutator is shifted back instead 
of forward, the contact is made later — thia 
is called ''retarding" the spark. 

There are two methods for advancing 
and retarding the spark; (1) by hand^ called 
**manuar' method, per fig. 6, chart 106; 
(2) by a governor arrangement, as per chart 
117, which is automatic. Both are ex- 
plained under the ''ignition timing'- in- 

The setting for the time of spark to occnr 
is done by placiiig the contact at a certain 
position p as explained under ''ignition tim- 
ing.' ' 

The gas throttle lever is the lever used to 
run on and is the lever used to increase or 
decrease the speed of an engine. This is 
done by opening and closing the throttle, 
as explainod under the subject of carbure- 
tors (see pages 67 and 68.) 

It la well to run with the spark lever aa 
well forward or advanced as possible, as it 

will tend to keep the speed of the engine 
op and consume less gasoline and create less 
heat. If the spark lever is too far ad- 
vanced then the eiigine will pound or knock 
because the igniton will take place before 
the piston is over the center. A retarded 
spark produces heat— see page 319. 

The amount of advancing and retarding 

of the spark by hand, must be learned by 
actual practice in order to get the best re- 

Wo have explained the essential principles 
>^ Hf eoil ignition; how the current is passed 
Qingh the primary winding from a bat- 
r^Bfy or dynamo; how the contact is made 

♦a^The Coil Condenser. 

on the commutator and timer; how the flow 
of current is broken suddenly by means of 
a vibrator or timer and how the intensified 
spark is utilized for ignition. 

— continued on page SSf# 

tVot«— A commutator is really tho segmontB on Sk d^roAnio connected with the armature coils, and on 
«%t«ta brushes rest. It really should never have been applied to the ignition, but is so well known aa 
^#B early form of contact, hence we will use it as explained. The Ford uses what is termed » oommu- 
alor. See pago 225 for difference between a commutator and a timer. 

'The adTaccing of the spark and relation of the ipeed of engine to the spark i% U«%\«^ -^xl^xk 
t**%Bltion timing'* also. **See pftges 22S and 245 for coll condotaBer And pftK« ^1^, mik^e^Vo cou^vclw 

Tlio Condenser'— below. 

A condtnBWr le eoiinecti»d witli the primary circuit of «l] lil^h tcoiioo coils with or withonl iribri 

ton, vlfto In connect inn with primftry winding on hi^h tenaloii magnctoi. 

Th% pnxpose of the condenaor ib to intooHify ths ipftrk at the points of the spark pluff and ftlio to pre^ 

v«dI e^ceitivA Aparklog at tb« end of the platinum contact points (0) on the vibrator. If sparking: at tho 

Tlbrator ii permitted to continue the point of the latter wiJI wear and bccomn pitted and will stick tof«th«r. 
▲ coiid«!Li«T is ustiilly pUcfld In tht bottom p^rt of tbo cotl box and conalsta of m number of oondvo- 

%ai%t whieh in this tftso urA leaves of tinfoil, toparatod by paper, covered with paralTine^ Paraffin« papor 

U asnally employed, but mica or some other Insulating mutGrial may be used. 

Th0 alternata layert of tinfoU are connected to^ethar and the remaining layers connected toreiber *s 

■hown at (D>. (see alao page 329). The two termtnals of the condenser arc eonnected or **britlfed** aerosa 

the points (0) in the circuit as shown. 

The function of tbe condenser la to act aa a bnJTer to the current at the moment thet the cirenit el 

eoDteet points (O) &re broken. Its ArsI duty, undoubtedly la to absorb the spsrk at the contact polste. 
Not only does the condenser absorb the sperk from the contect points (O), but it refer see the dlree- 

Uon of the cn^ent in the primftry wixe (P> and chari|:ea the poles of the magrnet or core. Tot instance, 

end of core wLich was north pole of mef* 
net suddenly becoinea louth and vice verea. 

The reason for It Is this; We here 
seen that any change takLng place in aa 
electrical conductor induces electric onr- 
rents in oeiehboring condnctora, accordl&f 
to the intensity of the chang*. Now* the 
sudden change which li canaed to teJte 
place in helf the tinfoil of the condenser, 
when the current is broken by the vibra- 
tor blade (V)» causes powerfnl cnrreDta 
to be induced in the other half of the 
sheetH of tinfoil which are coni^ected io 
the adjustable screw (R) end therefore 
to the primary windinft and as theee 
Induced cnxrents Itow in Hie opposite di- 
rection to the currents cansia^ them they 
send e current through the primary In the 
opposite direction to the current thel WM 
flowinf before the vibrator blade brefce 
contact. Thus the cnrreot in the prlnwry 
Is not merely stopped but sctnally re- 
versed. The effect being greatly to In- 
tensify the high tension current in the 
thin, secondary wire and therefore to pro- 
duce a more powerful si>arlE at spark ping 
(G)« See pstre 273. magneto condenser. 


NO. 10®— Diagram of ConnectlonA of tlie Splitdorf 1, 2. 3 and 4 Oyllmdef Vll^rator Typt of 
Oksdis, The coils are contained io a coil box and can be removed. Each coil is called a "OoU 
Unit,'' A Condenser; principle and conneetiona. gee page «oa for e •Votlbox" snd *'nnlt.'' 




And DOW we com« to tliG condensor which 
ii usually built iu the lower part of the 
ooil where it ia aecurely enclosed. Its func* 
tiOQS sue as follows: 

We have seen that the intensity of the 
eeeondary current or spark depends upon 
the Buddezmess with whi(?h we can break the 
primary current and destroy the magrnetic 
linee of force. 

One might therefore ioiagine that the 
mere act of mechanically dividing the cir- 
euit would suffice, but it is not so^ for this 
re&son: — The effect of separating the con- 
tact points is mainly to induce a high-ten- 
sion current in the secondary coil, but un* 
fortunately this induction law does not con- 
fin© its attentions entirely to the secondary 
winding, but proceeds to induce a high-ten- 
sion ''foUowon" current in the piliaary 
coil itself, thufl defeating our efforts to get 
a sudden cessation of current here. 

Not only so, but thb current, having a 
high potential (i. e., is capable of jump- 
ing across air gaps), promptly makes a tem- 
porary arc between the points which have 
jnst separated. It therefore performs the 
double iniquity of (1) destroying the 
strength of the spark by preventing the 
primary current from stopping instantaae- 
ously and (2) of burning up the platinum 
points by the hot electric arc which is 
formed at the break. 

High Tension 
The manner In which the parts of the 
high tension Ignition circuit are connected 
together is shown on page 218, fig. 1. From 
the battery is led a ground wire^ attached 
to any convenient part of the engine. 

When the commutator connection on en- 
gine makes contact, the current flows from 
the battery (if a battery is used), from 
the positive (+) pole through the vibrator 
and the primary winding of the coil, through 
the contact segment of the commutuator, 
through the roller, and by the metai of the 
engine and the ground wire back to the bat- 
tery at negative pole (N — ). 

As soon as the primary current causes the 
vibrator of the coil to operate, the "second* 
ary" or ** induced" current is formed, and 
goes to the spark plug, where it jumps the 

High Tension 
The following are examples of the high 
tension vibrator coil system of ignition, 
nsiag a commutator, IThe coil box is usual- 
ly placed on the dash, but wherever its lo- 
cation may be, it should be carefully pro- 
tected from moisture. The coil box contains 
as many coLls as there are cylinders. Each 
coil is called a **unit»" 

Tig. 1, chart 107, page 224. Connecting a 
ooe cylinder engine with a high tension coll 

We must therefore take steps to stop this 
and have accordingly, recouraed to the con- 

This' is composed of 
a large number of 
small sheets of tin 
foil, insulated from 
each other by sheets 
of mica (or in the 
case of a coil by par- 
affin paper) and tight- 
ly pressed together^ 
All the even numbers 
are connected up to 
form one pole, and aU 
the odd numbers to 
form the other pole. 

The condenser is "bridged*' across the 
contact points C, fig. 5^ page 228, or contact 
points of a magneto (page 274), in such a 
way that when the points separate, the con- 
denser bridges the gap and acts precisely as 
a spring buffer. The high-tension ** follow- 
on ^ ' is, BO to speak, forced into the condenaeri 
which on becoming charged instantly forces 
it out again by a species of electrical rebound 
not only checking the current but momen- 
tarily reversing its direction, which is of 
course even more effective. 

The intensity of the secondary or firing 
spark IS thus increased ten-fold and the 
primary spark at the contact points reduced 
almost to invisibility, (see also page 273.) 

Ootl Clxcult, 

•^gap'* between the points, at **X*' and re- 
turns to the coil through the metal of the 
engine and the Beeondary wire. We ex- 
plained on page 221 how the current is "in- 
duced** from the primary winding to the 
secondary winding. 

The nsnal trouble In the operation of the 
jump spark system Is the fouling of the 
spark plug hy carbon from a mixture that 
is too rich in gasoline, or by the burning of 
lubricating oil. This carbon deposit short 
circuits the points; that is, it is easier for 
the current to go from one point to the 
other by runtiing over the carbon, which li 
a conductor, than by jumping across the 
gap on the plug. The result j engine misses 
explosion (see charts 112 and 113). 

Coll— Wiling, 
sjrstem; when the engine of an automobile 
has but one cylinder, it is usually placed in 
a horiJcontal position under the body of the 
car. The location of the battery, coil box 
or other parts of the ignition system de- 
pends on the design of the car. 

•The switch is usually placed on the 
coil box. One wire from each set of bat 
teriea, usually from their positive poles, 
is connected to one of the switch terminals, 

*Ia thii illuttrfttioD th« poiitire ( + ) lido ii sTounded. ftnd the neestiTe ( — > tide ii eot)D6ci«d to 
•wllch. Howei^r, it mskei no mttlt^riBl dlffereaee. In fact it it a good idea to oceafttODftlly chaoga 
|i# ftow «»f eurrent, to prevent the [>1aiin-m paioti of the coil "pitiiojf" as ezplalned uuder deicrtption 
•f the atirat«r-Eeiit DepoUriier Switch, chart 117^ tg. 5. 
ta«< vg* 003 for muitratioti of a "Ooll t»oz'' aad "Coil unit." **at« pigt 22& ft.g. ^, vb^ ^v V 


Wig. SM—aUo lefl fig. 

Fig. 1 — A master Tlbrator coll on » four cylinder engine as an example. SW — secondary winding. 
PW — primary winding. P — primary wire. VB — vibrator. VS — vibrator screw. C — ^oils. BB — buss 
bar, connecting all primary windings at one end. SO — secondary ground wire. Fig. 2m shows how the 
vibrator on the coils CI, C2, C3 and C4 are short circuited. 

Tbe purpose of the master vibrator coil is to do the vibrating for the other coils. 

For instance; quite often multiple cylinder coils with several vibrators cause consider- 
able trouble from the "sticking" or welding together of the platinum points, causing missing. 
Where a multiple unit coil is used, a great deal of care must be excercised to keep in 

proper adjustment. 

By placing a single wound master vibrator coil in series with the primary circuit, and 
by short circuiting all of the vibrators on the coils, the one master vibrator will do the work 
for the others. 

It will be noted however, the other coils are used for making the spark otherwise. Also 
note there is but one winding on the master vibrator coil; its purpose merely being that of 

On the above diagram, note the firing order is 1, 3, 4, 2. No. 1 cylinder is now firing, as 
coil (CI) and contact on commutator (1) is in operation. The next cylinder to fire will be No. 
3 Trace diagram with pencil. 

Note all of the secondary wires are "grounded" on one end. This is usually done in the 
coil box, all connections being made to a binding post. ' A ground wire is then run to the 
frame of engine from the binding post. 

Pig, lA— A high tension distributor or synebronons systom of IgniUon. P— primary winding. 8— 
aooondarr. Note one end grounds to enfhie: usiiallj grounded on the coil. V8 — ^ribrator serew. 

Fig. 2— Note distributor and eommuUtor are together. The wiring diagram shows the two separated 
merely to explain the action. 

A flistributor system uses but one vibrator coil. Thus doiAg away with a great deal of ^ 
complicated wiring. Instead of a commutator being placed on the end of cam shaft, a com- 
bination of a commutator and distributor a^ shown in Fig. 2, is placed there. When one 
makes contact, the other does also (this is called synchronously, or meaning at the same 
time) . 

The purpose of the distributor is to distribute the secondary current to each spark plug 
at the right time. Note No. 1 is now on contact on commutator, also on distributor. No. 3 
will fire next. (See text.) Note all the terminals are connected together on the commutator. 

OHABT NO. 110— A ICaster Vibrator High Tension Ooil Ignition 8yst«nL .A High Tension Distrl 

butor or Synchronons System. (Note the master vibrator system would also be termed a syn 
cbroDouB sy»tem.) 
^^ /Mitfie ^M far K. W. Jfa«ter-Tlbnitor. 



to that swinging the switch blade from side 
to side throws one or the other into circuit. 
The nej^ative terminals are grounded hj be- 
ing connected to the metal of the engine, 
using one wire for both, 

The primary terminal of the coil box is 
keonnected to the binding post of the commu- 
tfttor; when the commutator in revolving 
makes contact, the current flows through 
the shaft to which the commutator ia con- 
nected and through that and the metal of 
the engine to the ground wire and battery. 
_ThoB the only primary connection to be 
laiade are from the two sets of batteries to 
the switch; from the batteries to the 
ground; from the primary binding post to 
the commutator. The secondary terminal 
of the coil box is connected to the spark 

rig, 2 J chart 107, page 224: Two cylinder 
engine with high tensloii vll>rator coll, using 
two seta of dry cells: The coil box contaiiii 
two coils, one for ©ach cylinder and is us- 
ually located on the dasb. The box contain- 
ing the batteries is usually under the seat. 

The connections from the batteries to the 

^^twitch are the same no matter bow many 

(^Oa there may be; that ia^ each set is con- 

'iiected to a switch point, and one ground 

wire for both. 

The commutator has two binding posts, 
one for each contact point aod one primary 
terminal is connected to one of the contacts, 
the other primary terminal being connected 
to the other contact. In the commutator 
shown in fig. 2, chart 107, the crank is 
supposed to be 180 degrees, which in chart 
52, fig. 3, was shown to produce two power 
trokes in one revolution, followed by a 
evolution without a power stroke. The 
contact points of the commutator are sep- 
arated by a distance that re<]uires the crank 
ihifl to make a half revolution or ISO de- 
gree9, in order that the moving part may 
move from one contact to the other, or SO 
degrees, and then a revolution and a half 
to move it to the firat contact point again. 
Tkis, of course, is uneven firing. The plac- 
ing of the segments on commutator there- 
fore must be 90 degrees from iral to the 
second segment, then 270 degrees to the 
next (commntator revolves one-half apeed 
of engine orank). 

If the crank shaft of this vertical engine 
were 360 degrees, as in engine fig. 2, chart 
52; the contacts would be on opposite sides 
of the commutator like the commutator 
shown in fig. 2, chart 109, so that the crank 
fthaft would make a full revolution to turn 
the moving part from one to the other, be- 
eanae a erank shaft of this kind permits a 
power stroke every revolution. Because a 
horisontal two cylinder opposed engine per- 
mits a power stroke every revolution this 

last described commutator is also used on 
it. ^fig, 3, chart 107,) 

Fig. 1, page 226: Four cylinder engine 
with a Mgh tension vibrator coll system, 
using two storage batteries: The more 
satisfactory system for a four cylinder high 
tension vibrator coil system of ignition (we 
will make exception of the magneto and 
Delco, Atwater-Kent and systems of this 
kind, which are treated later], is with a 
storage battery as shown in fig. 1. One 
battery is used for regular work, the other 
for a reserve. Or a set of dry cells could 
be used as a reserve. The wiring of a four 
cylinder vertical engine is the same in prin* 
eiple as that of engines with fewer cylin- 
ders, there only being an increase in the 
number of parts. 

It must bd remembered that, for reasons 
given in chart 53, the order in which the 
explosions occur in the c^^Iinders is not 
regnlat« 1. 2. 3, 4, but Irregnlar, being l^ 3, 
4, 2 Of 1, 2, 4, 3. While either of these 
may be used according to the action of 
the exhaust valve, the former, 1, 3, 4, 2, is 
in moat general use as the engine ts con- 
sidered to nan with less vibration than with 
any other firing order j therefore, we will 
connect this commutator and coil for a fir- 
ing order of 1, 3, 4, 2. 

The wiring connection for this irregular 
firing, is made hy changing the connections 
on the commutator, causing the spark to 
occur in the proper cylinder at the right 

Eef erring to fig. 1, chart 108, it will be 
seen that connections are made between 
the primary terminals of the coil box and 
the commutator, so that the current of No. 
1 coil leads to the contact on the commuta- 
tor which makes connection to cylinder No. 
1, which is now at the end of the compres- 
sion stroke and ready to fire. 

As the commutator revolves, the next con- 
tact to be made is No. 3, on commutator 
which is the next cylinder to fire. Cylinder 
No. 4 fires third; therefore coil No. 4 is 
connected to the next commutator contact 
to be made. The next cylinder to fire is 
No. 2; therefore No. 2 will fire after No. 4. 

The connections between the secondary 
terminals of the coil box and the spark 
plugs are in regular order; coil No. 1 to 
spark plug No. 1, coil No. 2 to spark plug 
No. 2, and so on. 

It must be understood that the proper 
connections are made in the coil box by 
makers to permit the secondary current to 
return to the secondary winding over the 
commutator and ground wire. In fig. 1 this 
connection is made inside of coil where it 
says, ** primary and secondary connect 







The Master Tibrator ColL 

With the ''high tension-' vibrator coil 
a^reteni, just descriV^^d (chart 108, page 
226); as many eoil units, oarh with vibra- 
tore, wouJd be provide*! as the engine had 
cylinders. If a four cylinder engine; four 
vibrator coiJ units would be necessary. If 
a six cylinder engine; six vibrator coil 
unita would be necessary. 

It will be noted that with thia number of 
vibrators, one or more would be constantly 
fticking, unless a great deal of attention 
was given to them. 

Therefore, by using a master vibrator. 
only one vibrator coll la used, which is con- 
nected with the other coils as shown in ig. 
1, chart 110. 

The master vibrator coil has but a ilngl^ 
prtmazy winding, and is connected in series, 
80 the primary current must travel through 
it before reaching any of the coils. The 

^ usual commutator is em|>loye<!. 

The master vibrator coil can be connected 

with a '* multiple'* of coils, by Bcrewin^ 
down the vibrators on all coila and abort 
circuiting them by connecting as shown in 
fig. 2M^ page 230 and fig. 4, page 264. Note 
the coils are the regular double wound, high 
tension coils^ as shown on pagea 220 and 

Tbe advantage of sucli a system ia thai 
there ia but one vibrator to keep in adjust 
ment, since this vibrator serves for all the 
cylinders; whereas, with one for each unit, 
al! have to be kept in adjustnient and the 
difTiculty of keeping several adjustments is 
a considerable factor. 

Tbfl disadvantage ia the great amount of 
wiring necessary with the multiple coil sya 
tern. Although the master vibrator ia eas- 
ily connected and requirea very little wir- 
iDg, the '*dt8tributor^' system which will 
be explained next requires considerably leas 
wiring. The master vibrator is an excel 
lent addition to be applied to a multiple 
system of ignition, already installed. 

♦The '* Distributor** or Synchronous System of Ignition. 

In the foregoing examples it will have 
been noted that the amount of wiring re- 
quired for engines having more than one cyl- 
inder becomes increasingly complicated, A 
ayatem now generally used^ known as the 
♦'distributor system/' very considerably 
simplifies the wiring, and at the same time 
more accurate timing of firing of the re- 
spective cylinder is obtained. (See fig. IA, 
chart 110.) 

One tremble coil only, is necessary » this 
having the high-tension terminal joined up 
to the ** distributor/' which is a special 
form of rotating switch highly inaulated« 
which directs the high-tension current to 
the cylinders in ♦be required order. 

The distributor brush (B), rotates at the 
•ame speed as the commutator roller con- 
tact maker^ and in perfect unison with it; 
that is to say, when the low tension circuit 
i» completed, the high tension circuit ia 
completed likewise The diagram should 
make the system clear, it being borne in 
mind that the distributor is rotating as well 
as the contact maker^ and in perfect ** syn- 
chronism" with it. 

The secondary distributor is made in com- 
bination with a commutator, each with as 
many contacts as the engine has cylinders 
and with the moving parts of each attached 
to the same shaft and revolving. (See chart 
No. 110, figs. 2 and a.) 

The battery is connected to the single coil 
in the usual manner, and a wire is run from 
the primary terminal of the coil to the 

commutator, where it ia connected to the 
four points. Thus when the commutator 
revolves, the current is passed through the 
one coil every time that contact is made. 

If with this arangemont a wire waa run 
from the secondary terminal of the coll to 
the four spark plugs^ sparks would pass in 
all four cylinders whenever the timer made 
contact. Instead of this, one secondary wire 
ia run from the secondary terminal to the 
moving part of the distributor, and from 
each contact point of the distributor to the 
proper spark plug. 

When the commutator makes contact, tod 
the secondary current ia formed, it fiows to 
the distributor^ which at that instant has 
made contact with one of the points, so that 
the secondary current flows across the con* 
tact and to the spark plug that is connected 

The advantage of this system is that 

there is only one vibrator to keep in ad 
justment, and fewer parts. The disadvan- 
tage is that the coil haa no rest, and the 
constant use tende to heat it, and destroy 
its insulation. The constant action of the 
vibrator is liable to burn the vibrator 
points, and destroy them. 

Therefore the modem ignition system, 
using a ''distributor system'* of a tlmllar 
principle, as the Deico and At water-Kent 
systems; the *' vibrator'* ia not used. The 
timer being of slightly different construe 
tion obviates the necessity of the vibrator 
Thia latter aystem ia explained further on 
in this instruction. 



*The principle of thii tyitem ii «Lmilar to Delco ft«d Atwutor Kent modem battery mud eoll leal 
tioti •yttema. exrept the «ystemv mentioned, ate » form of timer, called an '*intem»pl«r," ' 
di«penaiiif with the vibrator on the coll-- ( treated taparately farther en). 




and Gaps. Size of Spark Plugs; Regular, A. L. A. M. or 
S. A. E. Testing Coils and Spark Plugs. Ignition Wiring 
Troubles. Dressing Platipum Points. 

fouled. The spark plug causes mere trouble 
in this respect than any other part of the 
ignition system, (see pages 218 and 237.) 

The cause of spark plug sooting and pre- 
ignition: tA poor grade of oil will turn to 
carbon (soot), and will deposit on the end 
and inside of the spark plug and ''short 
circuit" the plug so that the spark will not 
occur at the point and consequently cause 
missing of explosion. 

Poor oil will also leave carbon or soot 
deposit on the end of the piston and inside 
of the combustion chamber. This deposit 
hardens, and sharp points of it will project. 
This projection will become heated white hot, 
causing the gas to ignite before it is time 
This is called premature or "pre-ignition." 

Therefore, spark-plug troubles are usuaUy 
as follows; short-circuited from carbou, 
cracked porcelains, electrodes burnt away, 
not pressure tight, moisture condensing on 

Tests and Gap. 

It is also essential that the battery be 
kept charged so it will deliver its proper 
▼oltage with a "single spark" system — as 
it is quick and must have pressure enough 
behind the coil to cause a hot spark. 

ttif points are too close, it will be impos 
sible to run slowly, for the actual area of 
the flame will be too small. 

tflf gap is too wide, misfiring (on a high 
compression engine) is apt to take place, 
especially when one tries to accelerate sud- 
denly, after going slow. The effect of open- 
ing throttle and admitting a full charge is 
to increase compression and it is well known 
that resistance increases with pressure. 

The coU will operate up to V62 inch, but bear in 
mind the greater this distance, tho more strain 
on coil and "leaner" the spark. 

The space between the spark points must be 
considered an insulator, and it must be remem- 
bered that the compressed charge in the cylinder 
through which the spark is required to jump is a 
better insulator than uncompressed air. 

A spark that will jump the point or gap of a 
spark plug when the plug is out of the cylinder 
may not have strength enough to jump when the 
plug Is screwed in the cylinder and under com- 
pression. So the spark must be especially strong. 
and should be able to punch a hole through a 
visiting card held between the points. 

♦♦Therefore the gap depends upon; (1) the 
kind of ignition system; (2) the amount of 
compression of engine. 

tSee repair subject, "pre-ignition and carbon removal" pages 639 and 623. *Location of the 
spark plug is usually over the inlet valve, see page 219. Also see page 239 for size of spark plur 
for different cars. **\Vhere engines are high compression the gap is not made l^ss, but the coil 
is supposed to be made stronger to take care of the extra high resistance. With magneto ignition 
the gap is important, see page 275. 
♦•*See page 171. tSee pages 275, 299. 298, 297. 312. ttSee also pages 250, 275. 

tif porcelain of ping is continnally sooty, the mixture is too rich; if the sool^ d^v^^^^' '\^ \i;x^^^>}, 
then too much lubrication — see pages 586, 630. 

Inasmuch as we will deal next with coil 
ignition systams without the vibrator, it 
is well to review the troubles caused by vi- 
brators and their relation to the spark plug. 
We will also refer to troubles caused by de-* 
fective wiring, commutator, etc. 

When the engine stops, one or more of 
the following, is likely the cause; (l) out 
of gasoline; (2) carburetion defective; (3) 
ignition defective. 

Under the subject of "carburetion** will 
be found the carburetion, gasoline and kin- 
dred troubles and remedies. 

If the trouble is not with the carburetion, 
then the trouble is likely due to ignition. 
The following may be the cause; broken 
or loose wire or switch, run down battexy. 

«*«If the engine misses explosion — the 
trouble may be due to carburetion at fault 
(see carburetion). If the trouble is not 
with carburetion, then the chances are the 
spark plug is missing on account of being 

"CSpark Plug 
To test to see if the spark plugs are miss- 
ing, see page 237, figs. I and 2. Another 
method, if a vibrator coil is used, is ex- 
plained in fig. 1, page 236. 

To see which spark plug is missing, see 
pages 237 and 236. 

To test the spark plug itself, see fig. 2, 
page 236. 

To see if spark plug is leaking around 
the porcelain at the top (A) of bushing or 
below (B) where bush- 
ing is screwed into the 
shell of plug — squirt 
gasoline at these points, 
engine is running and 
note if bubbles appear. 

Plug Gap. 
The gap is the dls- 
t a n c e between the 
points on the plug 
shell and electrode (see fig. 3, page 218), 
It is important that this distance be exact. 

tA magneto should not have too wide a 
gap, because when engine is running slow, 
the current is weaker. See also, page 275. 

Where a vibrator coil is used, the usual 
.iistance is about 1-32 inch. With a * 'sin- 
gle spark" system, however, as the At- 
wster-Kent, where the spark is very quick 
the gap must be very small, about .025 of 
an inch. In fact this is the average distance. 

Tt^ S Aws pntlnc and i» th.- 
II*.'* fc ;r:.;.*r:T bci contact-poi:.t 
i-i.'. 7 fcrr.t ef kt. 

F:€^« if th» mult of a bmdly- 
MS *ir'* > rt . vk.eta is worn un- 
•— _j«r iftrjcT-i lU4.l'»i-i"-*i« .:• -!!:•. r^et-r -s.* j>ljitiniuB would have 

IT I -r-t CMT* 10 ibe Heel and the 
:•: mix «a: iLe rivet hole aod causp 


pclsts. remember that the 

'-"z^z'* ur* :: TfrmoTe only a« small 

!• -aLj.t> it«a: aa possible and trim 

::- ♦vr'fc-* toti ..-* asd smooth, and in making the 

^ ^ -^ ^ T-rac-- O;- ^^- a::x.f=2:-!r:T :f tie wrew. do not aet the plat 

,.*.,.-t » -v* - — -lati • i»-r t:ir r^-rcsaarr to fire a cood. steady 

-^r-ji ^B^sMKfer Tv»a.s^ Tfrj --"» '. :• S «»- :ua if -^m 

-s^ v*a4 J * XA-I-. TJ*fx. *e»»- ^ _ . , 

• -:.---^.. A*' --. •-. -. -.^": .-. -t. ii-» «* trwcar tj« jMSsts faiso magneto poinri: 

' .r . '.--- -.1. --- -.^ :v.i*-i i-- n.-. i.1 ^ «BJ._ ;.f^*>r» flet are sold at acceaaorv 
- » •-, a.--: •'.': '.'.'.VT yi-^- »: "4 -5 .» a 'err "iia mad finely cut file. 

^^' 'i jr. 4V*^ ■''^*^-^" If rxsfaos are luts^ Uackened inaerC a itr-r 

*'' ■ •■»»«- .* -,• *.2^^ ti-.»r«-frea the two pointj^. xzl 

■» --. -. f'.T.j riarf*-: ■■ - '•* •*;•«=' ^impi ih«m a few times. 

■ 'tz- -.»•••'; •■• '"■'■•'" As rC leiac » ^z',iT.'.T.\ for dressing points — te* 

'^ . ■ ^ . - » • • • " i 1. - '" 

^- 2 ^ ' ' ,'x-\\' .-• -**-i+ - ^= y »i ' »Ti szii Tnnfsten Oontact-Points. 

• '^ "^ Ti.-*^- ir. VI IS a^'-erw Iikjb xx tr-u*» y^'attnam polnta when r!:r.«!i» 

•* rhtrv U a t'lrti'M'S* Sst' -T i-*^ ».rr»-ri :r TJtraCor aprinffs. Pla:x=T3 

-• ^ '' V' i^w f^»r'ta 1-.: v*^* * j-£-e= asi Tts^K-s isetal points are both ii*: 

.-* •-. ■-.* wxTC ;-»^**_- -^r^'^i.'^J^"- "^"* "'-- '**••*" »°d burn together a^i 

.-— .. _2^ 

'"^* » ii alloj. which consiats -if ^■' ~ 

:t i:*^ -.riiiam. should be asfi n i. 

Bakar points. Pare rVam 

T- :i 1 T.i^^r iiier s'>tion of intemxirt*-. ■.. r- 

f:r* ir.i -.31 Ttiri i» harder is used w::i :. 




;. .-t*i_ 



/ ■ 



..^.-i .-. 1 'a: '.' 


*Kitl* u« quite often used ea nzl su 
%a=«rr irnou iae to its eztreiae hastsen lau 
sfxaOftsr. Ml ita AsadTantages for mj^ma tm 
ac« is-ta: :r tf ;<oists when heary cxrrmn ir 
MJ-r>L T:e r\:fa::oa results in a hi^ rwiicaa:- 
:x-£e v^ :^ a.ak«« it difficult to start, axii ^e \r 
:z^ 3LaSf« :'. t'tt difficult to disciacx'^ii Tin : 
'V*<r*-'#i :a-i* » r-:if«Mr if iefectire. TThen platinuK fr*ii:um "■: 

T^rtt ar* xm'£. ^xtreae arcing is always an nuii^ 
:::c :f a £«f«siTe condenser. Tasfstm t^-.s:* 
t iM^^rr^ "*.'.' ^J^ :i'ref"* rK-r=^ a greater condcnaer ."anat- :r ' 
«.. .■■•t4r* "-*■- - "^ *^- :TTr-.-:ai>* arnr^ than platinum does. 
. - «.i.'* *ir: ■ •'*— 

. . • .-r »-- - *'»'-« ^'*'' P Ui Ti« tiAitm la bait for an eaneacr tkss 

t 'a'^ ^'^i ::« T - ^^t at Ra:^ rssgsten can be as*i ra n-.i »£- 
• -.,•.:#•. i^rrr- ^aitfry sytt tuLt ete also page 3*4. 

vt^.-..e7 gea-* ecc=- Abcra appOea to contact polBts cs vftnnr tu 

" '»- ■.*•-.?'"* *"""- =■' f-r>tT* ar£ f;rizga. 
. \ , , ».: .: -r-.:: t* 

'' '* '' ''^^- 8patk Gap Bnggettlna 

De aet sit speik plug gapa ovar Vq± vait. 
'-^T.. ;.;: >v -.ri. i "..-rft? J»7 »»*' likely cause a 

«' ^i-i-'-! * ^^*l*.^*fa •Wi*- ic»:ixg Che spark, by 

....■■'•"■ wi ■-.- •-* - »^ • .^- 1, jrt aeparate the terwzBai ▼?!» nun ».!. 

■ - * : :'.- :if v.-*."-- »"■ break down the isMuaDSK. 

V:'zT^\OTZ. Drecmg do« Pitt«l" VUtfun : 

•*."i- t" - rrert. t^errf*?*. the pitting of paiua- e -f.! ■* « 

"* ,. ■.:^. s-V^i -'a—r*'** !>♦ »»*«rto geaeratca a^i«Mr *«ira«P -:^ 

.'. V- J-' ' --J-^jafe T?* f.T a siKpIc method of ac ipLa, i auar i 

Setting Gap of Spark Flug, 

Flrat tet gip «t .025 — if «iigrljio miMes, tbeo 
ti^ thu; remember tli«t tbe gtp tbould b« juit fti 
irid* AS the igaitiou Bystem will itaDd. 

To aptrtment — try lettio^ tbe plug point on 
•aT— one cylinder until it miiiea op ■ hajrd puU 
mp bill with throttle doted or as much cloied it 

it will put] the hill comfortfthly. 

Theo iiliphtl^ dote gsp and try hUl iKiln tud 

eontintie expenmentins in this wtuf until th« mim- 

ing atopt. When correct diitance ia found then 

aet the other pluRB nccordinely. See ftlio page 

I Spark Plug Constnictlon, 

Locmtlon— usually over the iniet valves 
on **L" type cyliitders and on the side, of 
"I" head cylio^lers. See page 219, why 
flpark plugs are placed over inlet valves. 

Where plugs are uaed on overhead valve 
engines or high compreasion engines the plug 
must be of good const ructiou^^gaB tight and 
free of electrical leaks — and are usually 
placed on side of engine (see Baick). 

Cfonstniction — There are two types in gen- 
eral use; the **scparablO** tjrpe plug where 
the insulation or core can be removed aa 
per figure 3, page 218, and the **liitegral," 
or one piece plug per figs. 5^ and 10, page 

The parts of a plug are; the shell or body 
which screws into cylinder (see 3, page 
21S); the insulatloii which is held in the 
■hell by brass busMng (N) ; the electrode 
which passes through insulation. Waahexi 
are used as a gas tight packiir^, per tig. 2, 
page 218. 

The insulaUon is somctimeH made of mica, 
bat owing to the construction, which is 
usually with washers, it leaks or pertnils 
current to pass to the electrode especially 
when oily. The best Insula tloB Is porce- 
Iftln and this^ unless of best grade (not por- 
ous)* will also leak, thereby weakening the 

Where mica is used on plugs on aeronautic 
engines, per fig. 12, they are used but a brief 
time and new ones substituted. 

tSeparable plugs have tendency to leak 
i&d caose missing, especially at low speeds 

and hard pulls or on high compression en- 
gines. The integral plug appears to gain a 
point in its favor here. 

Electrode should be made of nickel alloy 
— if not properly made it will expand under 
intense heat and break the porcelain. 

Cement^is placed around electrode— Hia it 
dries, it becomes porous and porosity meani 
electrical leaks. 

Therefore, it Is plain to see that "leakage 
of gas" and ''leakage of electricity*' are 
the troubles to be overcome in spark plug 
construction. Leakage of gas causes "leak- 
age of compression'' and leakage of elec- 
tricity causes a ''weak spark/' 

Poor throttling, poor pick up, missing on 
hard pulls and high speeds are frequently 
caused by using a poor grade plug. Of 
course there are other conditions which will 
cause this^ (see page 171), as carbonized in- 
sulators, or too close or too wide a gap at 
the plug points, or irapropor carburetion ad* 
justment, but assuming that these troubles 
are corrected the leakage of gas and elec- 
tricity are two essentials seldom noticed. 

Theref ore, the highest priced plug is often 
the cheapest. Likewise a poor grade coil 
when hot, will lose its eflficiency. 

Spark Plug Sites. 
Biflerent threads are explained on page 
238, Biflereiit lengths, see page 237 and 238. 

Cleaning a Spark Plug. 
Don't mar or glaxe the porcelain as it will 
cause "porosity'' and "electrical" leaks. 

See pages 237, 592. 

** Vibrator CoU Troubles. 

We will not deal with the modem * 'single 
tpark" coll troubles here but principally 
with tbe vibrator type colls. Tbe single 
■park coil is dealt with furtber on. 

Vibrator points sticking; where the vibra- 
tor type of coil is used. This is frequently 
the cause of missing of explosion. Tbe 
points bum together as explained on page 
234. The cause of this, is due to the "di- 
rect" current flowing in one direction con- 
tinuously, (see page 248, "depolarizer 
iwitcb.") Another cause, is that of using 
too much pressure or voltage. For instance, 
eoils are usually wound for 6 volts. If each 
dry cell gives 1^ volts when working, and 

*^o tMt • high teaston coU, aee p*ffe 230. 

8«« pafea 360, 2S1. 258. 354. 276, 286. 288. 292, S09 296. 312, 296. for dielASCS to let tpftrk pluff gap. 
"*8ec Index, ^'Teatiuff Coila." 
ISeo paces 299. 29d snd 297 — for macneto interrnpter adjuatment. See pafta 29S and 171 for ndM- 

iAg at low and high tpeeda. 
ffleyarst* pings tboold hSTO good gaskets and drawn tight — ^aea page 239. 

•Its dliTieult to obtain a porcelain whlcb wlU not absorb oil and cauae leakage of electrieity throngk 
it. Boat grade come from France and Bohemia. 

five cells used, the coil points do very nicely. 
If. however, eight cells are used, the excess 
pressure is more than the condenser in coil 
can take care of; result excessive sparking 
at the platinum points on vibrator and 

To test the vibrators, see chart 112. To 
adjust vibrator and clean the platinum 
points, see chart 111. 

:tOtber causes of missing, as before stated, 
is due to loose wires or connections on bat- 
tery or run down batt ery^^ee page 241 
for loose connections and wiring and for 
testing batteries. 



Fig, 1— Teatlng for missing witb 
Tlbr&tors on tbe coiL 

Fig. 2^Ti]Bting ft Spaxk Plug. — PUce the «pirk plug 
oa the cylinder with wire coaneeted and switch on. 
Or»iik etiflnt slowly. If (he apirk orcuri At the f«p 
"X" th« p]ag ti O. K. T! it sparks up inside of tbr 
ahslt. between the porcelain and shell at "Z/* it it 
foaJchd and misses. li must then ba takao apart and 
carbon removed. 

Oauses of Spaxk Plug Missing. 

Tb« cause of missing of explosion Is usually dm 
to the spark plug becoming foul»d by carbon, soot 
depositing on the porcelain insulation, causing the 
plug to become short circuited. Generally caused 
D7 using a poor grade of oil or loose piston riai;s, 
which permits the oil to pass too frealy into the 
head o' cylinder. 

Othsr causes axe sticking vibrator points as ca- 

plaint'd on page 234. 

When starting to test, for the trouble. flrBt 
determine if the miiising occurs when running slow 
or when rannint; fast, or if at all times. Also be 
sure the carburstlou is right. 

Testing for Misk wltb Vibrators, 

We will assume the eogiue is a four cylinder 

To ascertain which, If any of the four plugs are 
fouled with oil, short circuit<'d with carbon or 
looperatiTe from soojp other c*n#e. open tiro throttl»» 
two or three notches to aperd %ip thp fngine; now 
hold your two fingers on twn outside tI orators so 
Ihat theT cannot buss. The evenness of the ex- 
haust will show that tbe olher two are working 
eorrectlj and that the trouble \p no\ th^re; or an 
oneveo exhaust will indicate that )t Is between the 
two that are free. 

If the two cylinders fire cvenlj change the 
Angers to the two inside vibrnror^ and sgain listen 
to the exhausl. Raring asrertniTjed in which pair 
the trouble is, hold down three Angers at a time 
until you And tho one which does not Are. 

OyUnder No. 1, ve wlU say, la the front eylin- 
d«r, and thi*y number in rotation 1. 2, 3. 4. No, 1 
coil unit w^nuld be the onr farthest from the itcer 
iug post (left side drive) and they number 2, 3. 4 
to the left. 

Testing Spark Plug. 

Tben r«moT« the spark plug and test tlio plug as 
ibowu In hg. 2. If the pluic ta O. K.. then you 
know the trouble is not in the plug. If plug la 
not O. Km then clean it or put in a nrw one. 

Ratnember the plugs may spark in the open alr« 
but when nndar compraslon fall to spark, because 
Ifae rc'SistancB ia greater. Therefore, be sore the 
points are not over V^^ of an inch apart at the ex- 
Ireme, for vibrator coil use. 

Vibrator GoU Cause of Missing. 
In rare Instances one of the coE sections will 
become short circuited or Insulation become punct- 
ured on the secondary winding. Caused by using 
too many batteries or too high a voltage. In this 
case the plug would not spark at all, therefore it 
mould be advieable to try changing positions of the 
roil units in the box, if the plug sparks O. K. on one 
of th« other coil sections, then you may know that 
particular coil unit is defective, Tbezefora, In- 
spect the platiniLm points on the vibrators and con- 
tact poluts, as tliey may be T>artially bnrned away 
or badly pitted if this coil aection still fails to give 
a epnrk. then it is evident it is burnt out inaidc. 

In some instances a coU may have its inmlakloa 
short circuited for only half its length of grinding 
and would give a spark. If i^hort circuit wss near 
the beginning of winding it would not spark at sU. 
See page 416. See page 241, for testing for t 
broken wire. 

Testing the GolL 
If multiple cylinder engine, test each unit sen ir- 
ately until it ia determined vhlch coll Is miaaisc* 
After assuring yourself the missihg ia not caused 
by a spark plug, weak batteries, carburetiou, or 
other causes, then test the coii itself, as explained 
above, see also pages 249 and 253 for teatinf the 
modern non-vibrator coil. 

On a non-Tlbrator type coll, the spark could be 
tested op to a jump of \% inch on a test — con 

On a vibrator coll, % inch. Don't plsce the 
distance ftirthi^r, as it is ltk«>ly to damage coiL 

To test a magneto — »ce ind^x. To teat for a 
broken wire — see page 241. To test for grounds 
and short clrcnlti — see index 

Other Causes of Hissing, 
Whan mls-flrlng occurs, particularly when run- 
ning at high speeds, it would be advi«abte to in- 
spect the commutator, as the fibre may be worn ao 
(hat the roller touches only the high spots, or It 
may be that the roller has worn out of round and 
consequently forms imperfect contact on all of tbs 

At stow speeds, it apt to be the result of Im- 
properly seated valves f^r air leak in the ci^rbttretor 
or cylinder bead gaskets. 

A weaknecs In comprassfon may bo detocted by 
lifting the starting crank slowly the length of its 
stroke for each cylinder in turn, In rare instances 
an exhaust valve may become warped by the engine 
becoming overheated, in which case the valve csAl 
will havo to be reground or the valve replaced. 

Other causes of missing explosion is due to weak 
battcritH. thiTt'fore te*t the batteries n« explained 
on page 241. 

0RA2T Ko. 112 — Missing of Bxploslon; Source of the Causes. 

The coil in this instance it the old style vibrator type and matter refers principally to the vibrator e^ 
Dutator system. The spark plug test is applicable to all systems. 


FlnfUng tlie Missing Spark Plug. 

rif. 1 — U«iM cock t««t: Open the relief cocki. 



for th« fiftm« 
out of each opening ftnd 
listen for the thurp re- 
porta of tha exploiiooi. 
The cjlinder without 
flume, out of nrhieh U- 
«uea onlj a biis, but oo 
thftrp report ii the one 
ftt fftuU. 

Ttg, 2^Anotber msthod 
U thai of ibort circuit- 
ing QUO ploff ftftex 
ikDOtlur. This mmf be 
<loa« by holding 
ft icrev driver or 
other luitniment so 
th&t it will in&k<? 
(^ooa««tian between 
the head of the spark 
plug and some part 
of the eajpine. Wheu 
iliort circuiting, note 
if engine seems to 
slow down, if ao, 
that plug Is 0. K, 
If there is oo differ- 
e&ce, then the plug 
likalf at fault. 
Hold the screw- 
driTW bj its wooden 
haudtaw else you may 
ruceiTe a shork from 
the iguitloii eurrent. 

Spark Plug LocatioiL 

Usual locAtloQ Is In oeigbb{»rbood of tnXm valTa, 
v^hich is correct, as it shuuM be sorroundfld by 
fro&h gas that enters during inlet «troke. If lo- 
cated CO exhaust aide dead gas wilt collect about 
(jlug electrodes and causa missing. 

Xt U tlio dofinbU to ht,r9 
plug wltare waiar Jacket nr- 
rounds It, as iu fig. 4, to avoid 
otrer heating, else plug elec- 
trodes are liabla to bacoma 
overheated and become Inean- 
descent and cause pre-Lgnition. 

Poor locfttioD ia shown in 
fig. 1. When set iu a thick 
valve cap (V) with short 
threads, dead gas aecumuiates 
in recess and causes missing at 
slow tpeedi. Fig. 2 shows an- 
other poor method, Tha re- 
cess accumulates heat aod 
metal extension la Habla to be- 
come red hot and warp elec- 
trodes altering liia of gap* 

Good location is where apark 
plug points or electrodes just 
reach the combustion chamber 
where cool fresh gas wilt coma 
in contact and flame will 
spread with maximam rapidtt? 
as in figs. 3 and 4. 

Wken plug extends too faz 
In combustion ebambar there la 
danger of valve head striking it. 

Spark plug lengths — see 
page 23'?. 

Fig. 1; Yalta cap 
loo thick — out of 
path of gaa« 

m i 

Fig. 2: Recess 
around plug shell 
retains heat. 

Spark Tlug Causes of Missing. 

Fig. 1 — Missing may be caused by tke spark 
arcing from shell to tbe terminal — cause: porcelain 
too abort and gup too wiJe at poiuts. 

Fig. 2— Points ni*7 have coma together — cMue: 
screwLug plug into cylinder bent points together. 

Fig. S— Wtro may have become loose from ter* 
■iDll-^canae : termlnat not ncrewod down tight. 

Flf. 4 — Shows method of adjnstlng the dlat&nce 
iMCiiMn tba points of the plug; distance should be 
about ^ of an inch apart for coil ignition, and Vi(4 
of an inch for magneto iguitioo .025 average. 

to t«Bt for a missing spark ping; first, open the 
relief rock to esch cylinder, as shown in fig. 1. 
If a blase emits from the relief cock, then the 
cylinder ia firing. It is advisable, however, to see 
that it fires ri^nlarly. The niiiiing may not be 
la the plug at all and a slight movement of the 
adiosting needle valve one way or the other on 
carburetor will remedy the trouble. Tf the missing 
18 In the PLUG, then it ma«t be cleaned. 

Whim u engine logins to misfire suddenly, from 
flOSMi unknown cause* the first thing a driver shoaSd 
do la to note whether the firing is regular: that Is 
if it occurs ia only one or two cylinders at reitular 
intervals in the cycle of explosions: or. If it Is 
intermittent in one cylinder or in dJCferenl cylinders. 

A regular misfire In one cylinder, that is, mis- 
Arlng that oecars once at the same time in every 
eyete of the engine, generally is caused by a de- 
feetive plug ot a disconnected high tension wire. 
Jl defe>ettve vslve also Is probable. 

I&ftannittent misfiring In one cylinder may be 
due to e defective plug or loose terminal connee' 
Hen or a valve that is not closing tightly. 

OtSktr cnnsee of xnisalng are: Worn timer, loose 
cesaectJon. platinum points on coil or magneto. 
nmA plog. carburetor needle valve and auxiliary 
w valve need adjusting; air leak around iulake; 
kattcry weak* 

Fig. 3: Correct position of plug in valve cap. 
Fig. ii Correct posittoo when aet in water Jacket. 
Ftg. 6: Plug reach too long, liable to strike valve. 

*To Glean Spark Plug. 

If the trouble is suspected of being a abort^dr- 
cuited plug, due to carbon, etc. (sec page 339). 
unscrew it and clean it as follows: 

To dean a apark plog: Unscrew the bushing 
which holds the porcelain in the shell, remove the 
porcelain {or mica) and sr>ak the shell and por* 
celain in kerosene or gasoline. Clean all carboo olF 
each. Don't scrape porcelain, as it will roughen 
the glazed part and cause it to retain carbon. If 
the oil is burnt on the porcelain, muriatic acid will 
remove it. In placing the porcelain back into the 
shell, be sure (he copper washer is placed back 
and bushing Rcrewcd tight to prevent leaking. 

If then impossible to get a spark at the plug, 
when laid on cyUnder. then atart inspection by test- 
ing batterieB aa shown on pages 241 and 460. 

If itlll unable to obtain a apark, then eKamlne 
the connections on the battery; one of them may 
be looHe or broken under the insulation or not sol- 
dered to the cofiper connection, as shown in fig. 6, 
page 241, or connection to storage battery terminal 
may be loose. 

If trouble is not now removed, then trace the 
wiring from the batteries to the coiK 8ee If tke 
wires have been allowed to get next to the bot ex- 
haust pipe: if this ia the case, make a metal **T" 
joint, as shown in fig. 11. page 241. 

AU terminals should be carefully inspected and 
all connections soldered. 

The ground wire fig. 4, page 241^ should be care- 
fully cleaned and scraped, as well aa the part of 
frame it is grounded with and drawn tight. 

If wires are suspected of being broken, see ludei 
"testing for open circuit.'* 

GBASLT KO. 118 — ^Testixig for Miaring EzplodOB. Sp&rk Fltlg Troubles, caiiie and remediM, 

* Alcohol is alio loitable for cleaning plugs, see also page fi92. 

J. I13B— Spark Plug Sizes used on ieading Automobiles, 'iTUcka, KLd\.qx 'B^^t^, ^^^xjX«\ 
Bi^UoBoty Mud AerouButSc Engines, 



Wlr« Used for Winding a CoU. 

Copp«r wlr* which 1« iiuiLlAt«d is used for the friodiDg of the primary and a««oiidftrj wlndinf of a 
hjfh tetitioa coil or maguoto armature. 

The prttoarj winding of & coll or (mafoeto armature) is called primary winding wire. It is nnwU/ 
ft aiJifle Btraod of aof( copper wire insulated with rottoa, Thia wire ia not lo long ai tbe flftCODdarr wind* 
inf. The curr^ot which paiiet throoffh thia wire ia of a low voltage, ttaoally about $ volta. The quAntltj 
or tmperea of current ia greater than io the iecoodar/ wiadtng. 

The aecoDdjUT wlcdlug wlro of » coll or (magaeto armature) ia wrapped over the primttrf winding 
ftod it la conaidorably greater la length. The inaulation ia allk thread, wrapped around a tery ftoe alngl* 
ttraod of flexible topper wire. The preaaure or Toltage paning through thia wire ia In the thoxLaasdA, 
hence the reaaon it must be well iniulated. but the amperage ii practically cone at all. 

The winding of a Boach DD4 magneto armatur«^, uiually cooalita of 3 layer* of No. 30 or 23 wire, 
to form the primary winding, and 70 to 72 layera of No. Sd silk covered wire to form the aecondary winding. 

The reader, howeTer, never hai occaiion to botbrr with wire on a coil or magneto armmlnr* 
U the work of a apetrialiat. 


Thar* u« three kinds 



Wire for Ignitian Systems. 

of Ignition wire for general use with the ignition ayatera of a ear, aa foUowa: 

Primary wire or csbZe, made of aereral atranda of tne 

m^n^M^^f^^ ^'^'^ ill ordf^r to make it flexible and ioinlated. oil and 
moiature pTOof. Thia wire ia uaually uaed between tho 
battery, coil and timer, for all tow teoaioa work, and must 
be of aufficieot aize to carry the current, uaually No. 14 
friie ia uaed. (ate pagea 425 and 427.) 

Svconduy cable it also made flexible and the inanla- 
lion on wire is much heavier Tbia it uaed to conduct tho 
high tenitioQ currt-nt from the coil or magneto to tbe apark 
pluga. It ahould be kept free from all metaU as much ai 
poiiible. 8ixe U uaually Ko, 16 or 14. 

Duplex cabla ia aUo flcjcible, but generally two to foar 
wirea are run io one insulation, of course, being aeparaiad 
from each other by Insulationa. Thia wire if generally Mad 
for ligbting and low tension work. 

Mttal conduit; a good plan in wiring a car, where aevorai wires are run together, li to oocloic the wlrei 
in a metal conduit, uee page 426.) 

Tho wires miutlag from coiU or magneto dlstrlbntor to the bpaik plug, carry the high tensioa eoiranl 
tad icre called SMOndary cables. This current eacspi^B more readily than from tho wires running from tba 
battery to timer or coil. Tbe wirea running to the plugs aro call»d "high tenaion" wirea because the tan- 
■ion or voltage ia high and current will often jump through the insulation and short circnil (cutting out 
■park ping) to any metal part it happeoa to be in contact with. Par this reason these wires must ba eara- 
fally protected and very hesTily tnaulated. (sea fig. 12. page 241.) 

The priiuary wires running from tha battery to tSmer or to lnt«rmpter on magneto ara **law tamltfii/* 
They do not need have aa heavy inHulation, but the conaeotiona should be well made and clean becauae the 
pfreSBure is so low the currt^nt will nor pa»» over dirty or loost' ronnoctkons, and a loss of current will 
rcsntt. AH connections ought to be soldered and taped, (see flgs. 6, 7 and 8, page 241.) 

The wires running from the battery or timer to the coil connection, are called the primary laad 
wires, also battery wires. The&e wirea mu»t be of aufficient sice to carry the current, as they carry a 
greater quantity of rurrt*nt than the secondary wirea. The secondary wiret have much heavier insnlaUon 
and from outside appearancet would aeem to be larger, but are comparatively small« aa they carry a high 
toltage but low amp<*rage. 

Don't UB« lamp cord wira ooder any eircamstan cea as it will give unsatisfactory resulti and eauaa 
miaslng if damp, (ace pAge 425.) 

The shie of primary wire geuerally nssd la No. 14 ar 16 primary cable — the secondary wire la 
limply called "aecondary cable/^ Both roiiit be waterproof and heat proof — ^(see pagea 426 and 437.) 

Wire for tha elctrtc horn is mually No, 18 — (sea page 425.) 

Making Ootmectlotia. 

A croonded connection should be filed or acraped bright before attaching the wire, and the eonnae- 
tion when made ahoutd be cohered with Tsaeline or paraflTiue. A copper washer should be placed itodtr 
the head of the screw, to bold the wire firmly ia position — and tightly drawn up. 

All coDnactionB must ba brlg:ht and dean, for a dirty connection will add reaiatance. Binding poaU* 
icrewa, and tbe ends of tbe wire must be scraped clean before th? wire is attached — this ia very import' 
ant on low voltage wiring. 

All connections ahould be made aa firm as poasible, tising pliera to tichten the binding eerewa. Tka 
beat connections aro made by brass or lead terminals soldeTed to the enJs of the wires. When a f oft- 
neetion has been nprewed tight, the binding screw and termtnst should be covered with vaseline or paraf* 
fine, to prevent corro*»ion» and the whole wrapped with electric tapp. This tape cornea in rollt, and ll 
sticky, BO that it will stay in position when once applied. In addition to bsing aa inaulator, it pref^enta 
moisture from getting at the terminal. 

Short lengths of wire provided with termlnala «re sold for makiug dry battery connections, and it It 
well to use them when dry batteries ar*« used. 

No posslbla cattse for leakage of tbe earrent should ba allowad; a single strand of fine wire proleeting 
from a fieziblo cable will ba enough to cause a short circuit if It should touch metal. <aaa pagaa 427 and 491.) 

;.T HO. 114~'Wl]idlng of an Ignition Coll. 

Ignition Wire — (al»o see pages 425, 426 uid 417). 



Tig. 1: MlJtins of Urnltlon 01*7 be due to «ra«k 
b»tt«rleB. To t«it, uie ah Amperemeter. Teat 
9ikch eel] •ec»Arihte1y by placiae terminftt of meter 
on lertniRfti of battery. Each bnttery ou^ht 
to «bow 15 to 25 ftxnpereB. If liuii than d amporest 
r«i>liM?«. If 000 thould lent say, 10 amperes and 
mn other 20. then the eood battery will be broufbt 
to the level of the poor battery. Remote it and 
put lo a fresh one. To teit a storage battery 
(K«e index). 

n^. 2; kn emaargency dry cell connection. Usual- 
ly iHo tela of dry cellfi are provided when ignition 
It on dry celli alone. Only one set at a time are 
u*«?d. however If both nets should run down, 
• mttltlple ronnertion of the two sois can be made. 
«• «hawu abore, which will wuffice to reach hoine. 
Dry cells are now scldoni used. 


!• flluiwii. 

3: Quite often oilaaing will occar from loose 
' at Ibe battery termlnala. See that 
^vayt tiffht. On iome conneetioni. the 
, le broke or not soldered well to the ter- 
JL ^ood connector called the '"Bull Do?" 

%%>r •nrfiKC 

Fig. 4: On many 
can one wire is 
grounded — there- 
fore it is eaaen- 
tial that the 
grounded connec- 
tion ii well clean - 
ed and then 
Hirbtened. A cop- 
'^ terminal 
uld be solder- 
- to the wire — 
) (tinned abd drawn tight with a bolL 

n|. 5: Wlten metal bittcry boxes are used and dry 
cmU placed In tbem, d . »t] iUort circuit th(» 

l»attenM through the fition around them 

*^erefore ketnj bo« nl«o ii,(iteh win* 

«b«re it pa«»e» through ih*s luvtal box 

rig. 6, 7 and a show how 
to make a eonn«ctloti with 
wire AUd terminal; »older 
and tape all conueetlo&a. 


nga. • sad 10: IClsilng fa tometlmet eanaed by 
lAOi« eoimeetlooi on the switch t^rmmalt arid bkt- 
•aty term mall. See that tertntnala are clesLn and 

Fig^ 11: A good method of 
protecting primary (bat- 
tery) wires when they mn 
along the frame, 

Fig. 12: Neat metliod of dlttrlbtitlng the ■econdary 
or high tension cabloa oti mum^yllnder englnei. 
A divided fibre tube supported on brackets encloses 
the cablfift and allows of easy inspection or renewal 
if required. Any number of leads or cables can 
be distributed. The eight plug leads required for 
dual ignition on a fonr-cylinder eogine can bo 
accommodated in two-inch flbre lube- 

Fig. 13: Oanaei of com- 
mutator troables; (l) worn 
metal so^icols (C). often 
cause missing by not mak- 
ing good contact. (2) The 
commntator may also be- 
I come looMe on the shaft and 
^^et out of time. (8) Spring 
weak, (4) Loose connee- 
tinns at binding posts. (S> 
Depr est ions worn on face 
of fibre on which the rol- 
ler (R) travels resulting 
_ in the roller Jumping (at 

high speu(U) alinoMl over the metal contacts (0). 
The roller (R) and p\n; of the revolving part will 
also probably be found in bad shape. To repair; 
turn down in a lathe or replace with a new one. 
fO> Orease will coat the Insulated fibre ring (0) 
from one Regment to another and cause a abort 
circuit. Too much oil will also cause a glased sur- 
face o7er the segments (B) and good contact can- 
not be made between rc^ler (R) and these metal 

*Flg. 14: How to test ignition circuit for a brokon 
wire: 8i^c»re a small 3 volt lump, connect one 
wire to battery terminal and carry the other wlro 
from lamp to the timer (placing timer ^rfrnient on 
contact), if the wiring Is perfect the circuit will be 
completed and light lamp, indicatint; that the wires 
are 0. K. A dmall electric bell is also suttanii] for 
rpfitinc lengths of wire in the same manuer See 
II ISO. page 737. 

rig. IS: Mark wires 
when removing, by ns- 
ine cheap water coiors 
or taf them, thus saY> 
ing a lot of time when 

CHABT NO* 115— Importance of Ck)od Oonnectlonjs and Protection of the Wiring. 

*s«o iodejt, * 'testing for grourid«, Hhurt circuits, coils" etc. 



fOpeti and Closed 
The modem *' Interrupter/' or '* contact 
breaker/' as it ia called, is very similar to 
the interrupter on the magneto and ia di- 
irided into two types; the open circuit and 
the closed circuit* The open circuit contact 
maker is termed a timer and closed circuit 

tl>reaJ?er an interrupter.** 
Open circuit principle; when the arm (B)» 
fig. 2, is raised, contact is made with tung- 
•ten point screw (Q). This closes the pri- 
mary circuit but it is immediately opened 
again; termed the open circuit principle. 
because the points of timer are normally 
0$«IL (see also pages 37S and 377.) 

Closed circuit principle; the circuit of 
the primary win ding on coil is normally 
closed, because points of timer are closed 
until raiaed by cam (D), When the *'cam'* 
or ** interrupter * * (D), fig* 3, raises the 
arm (B), circuit is momentarily opened but 
immediately clost'd again. Thi» is termed 
the closed circuit principle. This action 
** interrupts'* the ilow of current suddenly, 
hence the term ** interrupter/' 

Both of these systems have a "mechani- 
cal** method of making and breaking the 
primary circuit. Instead of the ** electrical** 
method, such as the vibrator In flg- 1, There- 
fore a coll, without a vibrator Is used and 
a ''single'^ spark is given at the plug gap, 
tzkstead of a succession. 

Both systems accomplish the same pur- 
pose, which is to interrupt the tlow of cur- 
rent in the primary winding in order to 
eftoje induced current of a high tension, 
to flow in the secondary winding as pre- 
viously explained. 

In the open circuit principle the contact 
must first bo made before the current flow 
can be Interrupted. This is made very rap- 
idly; quicker than the eye can detect. 

In the closed circuit principle the current 
la flowing in the primary and ia broken or 
Interrupted by the contact po^ts being sep- 
arated by the cam; which runs at cam shaft 

•The closed circuit advocates, cla^ the 
idvazitage of perfect synchronism^ due to 
elimination of ** electrical and mechanical 
lagi" whereaa the open circuit advocates 
daim economy. 

Electrical lag means that the spark will 
not occur in the same position as regards 
piston travel st any and all engine speeds^ 
with a very high speed the piston might 
have a tendency to travel past the point of 
ignition, before the open circuit timer made 
and opened contact, whereas with the closed 
circuit principle it merely opona the con- 

W1itl« aU Uf factori deal wftli time in leconda 
Iheir elfert on lh« eneiue is the number of de^eci 
tbey cftuie the vpftrk to orcur oGT the point it 
•houlfi. CooAeQQeDtly m time factor of only onc" 
tboi]»*ndtb of » second meane oqI; m v»riaitioii of 
3 dffr*vti at J^OO r, p. m. yet means 12 degre^a at 
SOOO r. p. m. and 16 de^eea at 3000 r. p. m. 

Mechanical lag is eliminated much for 
the same reason and the quicker and alm- 
plfT the mechanism to "interrupt** the flow 
ta the primary the quicker the spark. 

Circuit Principle. 

Por this reason some of the systems have 
been additionaUy Improved by adding an 
automatic advance of the spark, by a gov- 
ernor arrangement placed in the timer hous- 
ing, so that the timer shaft will advance 
with the speed of the engine and cause the 
spark to occur as near the proper time as 
possible (see page 248). 

Referring to fig. S, we have then a simpli- 
fied explanation of the closed circuit prin- 
ciple — note the interrupter (D). At a 
glance it appears to resemble a magneto in- 
terrupter or contact breaker arrangement — 
and it is very similar, although a magneto 
with its ^* alternating" current is not used 
to supply the electric current, but instead, 
a ** direct*' current is used from the bat- 
tery or generator. Yet the same princi- 
ple; Interruption of the current flowing 
through the primary winding of the coil ia 
exactly the same. 

For inatance, the flow of carrenl ttirough the 
primary wladlag of the coil ie auddeuly ''inter- 
rupted hy the cam rftiHiag the iciterrupteT arm 
(B> from contact (A); the current i* diverted to 
the condenaer (not ahowa here^ but a part of all 
cuLIh, BCtf fig. 6, page 223), wlikh ii charged to a 
frtirly liigh voltage and which then diichargei 
through the inductance of the primary winding of 
il^e coil ; causing a rapid deraagnettxalion of the 
iron core of the eaU that " Induces" the hi^h ten- 
eion curreni in the aecoadary winding. Thu high 
tenaion current ia then carri(^d from the "dietriba- 
tor** to tho ipark plugs. 

The syitem In flg. 3, hu been improved hj h*T- 
ing a cam (D) Tith the aame nnmheT of projeC' 
tloua aa there ore cylliidera, thereby readeriag it 
pi>»aible to operate the ' 'distrgbutor and timer or 
interrupter/' at the aame speed — see pagea 878 
and 377, 

The open circuit principle la carried out 
ill fig. 2, and is very much the eame, al- 
though the circuit is open at all times ex- 
cept when arm (B) is in contact with (T)j 
the spark really occurs just at the instant 
that timer cou tacts are opened, that is, the 
contact is **made*' and * 'opened*' andden- 
ly» meaniag practically the same principle 
as in fig. 3, where the circuit is closed un- 
til opened by interrupter. There are aa 
many notches (N) in cam (T) as there are 

Therefore summing up the three diatrlbu- 
tor systema of the battery a^d coll system 
of Ignition, we find that tho old style '* com- 
mutator '' system^ fig. 1, has been discarded 
and the two sy stems in general use are As 
per figs. 2 and S. 

The disadvantage of the ^'commmtator** 
system, fig. 1, is due to the use of a ** vi- 
brator'- coil. See instruction 2§. 

Another point to bear In mind is that 
both the open and closed circuit syatama 
give a ** single** spark, whereas the commu 
tator type gives a ** succession * ' of sparks, 
(see page 250.) 

Another point to remember is that a coll 
without a vibrator is used on both the 
"open" and ** closed** circuit battery and 
coll system of ignition— for previously 
stated a vibrator is not necessary with A 
single spark timer. 

I mi\ 

*Al«e claim that it allows the mazimaiD amoutit of ecmtact which periQiti complete aaturatioa of «iiil 

at high engine spredit — and no douht is a rensonable claim. 
TPace 243 shows a typicAl open crrcnit type. Page ZS4 a popular closed circuit type aystem. 8«^ *\«i 

pAgM 378 and 377* ••We do not adht^rii to ihis rule throughotit this booV aa VVie "wot^ \vm<!.t \% 

•ft«ii metitianed when it ia a filoted clronit tyve. 



242 DYKE'S IN^^ . 


The Timer and. 
Delco, AtwaitT 
house, Battery ;;ur^ 
and Direct C- J" 
Supply. Depp^V. 

tThe - 

<itf0i/f>f» TO Fmmnm. 

tad 41itribiitor for a 

\mk »s4 batl«rT ' * af atmn. Note 

««i7tfr«iv at different speeds. 

L>i^ caiB ilikft but turns 1% 

"^ ^smbuior bnmb (R) makes one 

— '- nsiag 

I L ^^ ^AfA. Tb*i i» tlUfl to 

1 L^ . 


f,Mtf^G f^AtlH C 

liagnato Type 

A first fiance at the intermptar 
and distributor, in As. 4, tbe 
reader woald think this a "maff- 
neto*' system and that ia the 
reason for illustrating it. To 
show the reader the simplieitji 
and to bring out the difference 
between the "timer** fig. 2, and 
"interrupter** system, fig. 8. 
page 242. 

The contact breaker or inter- 
rupter and distributor in fig. 4 
are of the magneto type and 
the principle is practically the 
same as a magneto, but the 
"source** of electric supply is 
not "alternating** current taken 
from a magneto, but is "direct" 
current, taken from a storage ba^ 
tery or "direct** current gener | 
ator if engine is ninning fast 
enough for the generator to over- 
come the battery Toltage and re- 
charge the battery as explained 
on page 837. 
Here we baTe practically the same principle 
as explained in fig. 2, page 242. except that the 
circuit is closed until "interrupted** by move- 
ment of cam. Whereas in fig. 2. the circuit ii 
open until contact points are closed by move- 
ment of timer. 

Zf we applied this system, fig. 4, this page, to 
a four cylinder engine, it would be neccessary 
to roToWe the cam (D) twice, during two revo- 
lutlona of the crank shaft, or the same speed 
as crank shaft, therefore the distributor would 
revoWe but once, during two revolutions of 
the crank shaft. Therefore the distributor 
would be geared to run half the speed of cam. 


It 4Hf«ii by *E**r "31 

iutAl wtittfl V^^^ from 

^4 «e the Stucltfbiiker 

^ (9,1 IntemiptPt' earn 

ifitodfbaleer fenerator 

lU^ ibd igplufiii is aa 

Lifr 8*8i 

3fi0. 312. 

We could use a cam with four lobes instead 
of two, and run 'it at one half the speed of the 
crank shaft, causing it to revolve once to two 
revolutions of the crank shaft; then the dis- 
tributor and timer would revolve at the same 
speed, or % the speed of the crank shaft. 

Six cylinder engine: Because there are but 
two lobea or projections on the cam (D), in ; 
fig. 4, and because it opens the circuit twice | 
during one revolution of the cam. we would | 
obtain two sparks during one revolution. If a | 
tlx cytlnder cugine, we would nerd 3 sparks to one revolution of ; 
erank thftft, or six sparks to two revolutions, therefore the cam (D) 
ibQAl tiira 1% times to one turn of crank shaft. 

Tho distributor, howevor, would torn bat 1 time to two revolutions 
of crank shaft, therefore it would have to be geared to run H the 
ipeed of the crank shaft, or 1 turn to two of the crank, bocsuse the 
bmah (R) mast make 6 contacts during its one revolution. 

▲ simpler plan, would be, to use a cam with 6 projections or lobes. 
Inateao of two projections, as shown in fig. 2, page 246. This cam. 
with projectiona would then run at the same speed, as distributor. 
or one revolution to two of the crank shaft. The Stndebaker and 
Beo, use a lyatem of this principle, which is the Remy system. 

The coil is a single **non-vibrating" type mounted above the start 
Ing motor and to the side of the dintributor and interrupter. The 
primary earrent ia taken from the battery or generator, through in- 
terrapter, thence primary winding of coil. It is there transformed 
into a high preeaare and carried from secondary winding to the dis- 
tributor arm (R) and distributed to the rpark plugK. 

jUfmrn iTf"" Interxnitar m applitd to the Modem Battery and Ool] 
^ (8ee P*ff* ^^ — ^^^^ Studebaker system.) 

Faitg of a Modem Battery and Coil SyBtem of IgnitioiL 
Th« parts of tMs STStem eonalst of distributor, timer, ignltioii coll, sparlE pluga and 
itorage battery — see page 264 for Connecticut, page 248 At water Kent, Dolco 127 and 377. 
Tba diatdbiitor la uaaally placed otdt the timer. First note the timer shaft wkich ia 
driven from the cam ihaft, usually by a spiral tooth jc^ear and at cam shaft speed, 

ttTbtt dlKtrlbtttor bmsh it 

in Halt Mn««. I« tfi* 
•»c«ndl»ry; th« In. 
n«reifcuJt, in h«iw]r 
lln«t I* th« 
•nary circttit 

coaoocted to upjuer end of 
Ihli fthftft and aa it reVoWei. 
uiftkea COR tart with the 
^park plug terminals. Kot« 
center contacl on rear of 
bruih, connecting with tee- 
ondary of eoli. 


The timer Ia that put. 
containing tbe intermpier 
or cont&cl breaker mectLaji- 
lim and Ia placed below 
Uie distributor. This mac li- 
aniem itmt^ly makea mad 
tben breaka the flow of 
current in the primarjr cir- 
cuit it open circuit tfpe, 
and opens tbe circuit it 
doted circuit t^po. 

Tbe Coll. 

It the tame principle of 
higli tention coil aa de- 
aeribed 00 page 220, but 
witlioui a vibrator, Tbe 
condenter caii be bailt in or 
on th& coil but it now often 
placed on tbe timer (t«i» 
page 252). The coil can bt 
mounted on the datb. tep- 
arate from the dittrtbutor 
and timer or adjacent to It^ 

Hi^b |>6»i«B roil *ilh<ntt vtbt*l^r 

'contact break* 

Tbe Condenser. 

For deacription of condenser and it« purpoa» 
isee Paget 22B anJ 378. 

tTo test condenter: remove the dittributor head 
and ha%e some one crank engine. Notice if there 
i& excaaslTa aparking at the timer contact points, if 
so, then coudcnaer it defective. A, tUght tpark, bow- 
evt^r, will aometlmefl be ebsorred with i ^ood can 
d enter. 

Testing coll: The mechanic thould familiarise 
himtelf with the tpark obtained bj removing tbe 
wire from one of the plugs and letting the tpark 
jump to tbe engine (not to the tpark plug). A 
rood coil will produce a tpark with a maximum 
lamp of at least V^ incb. provided other conditioni 
are normal. 8ie pngps 236, 253, 418 and 978. 

♦♦Timer Coatacta, 
The timer contacts are called ** interrupters'' or 
era^' and are shown on pages 252 and 378. 

Tbe timer contacts sliown at D and C (fig. 1), are two of tbe most 
important points. Tbej are tungsten metal, which is extremely bard 
and requires a very high temperature to melt. Under normal condi- 
tions they wear or burn very sMglitly and will very seldom require 
attention but in the event of abnormal voltage, such as would be ob- 
tained by numing wltb tbe battery removed (on generator alone); or 
with the ignition ^resistance unit shorted out, or with a defective 
i condenser, these contacts burn very rapidly and in a short time will 
cause missing. 

These contacts sbonld be so adjusted that when the fibre block B is 
on top of one of tbe lobes of the cam the contacts are opened the 
thickness of the gauge on the distributor wrench (usually furnished 
by the manufacturer.) — see page 378. 

Adjust contacts by turning contact screw C and lock with nnt N, 
The contacts should be dressed with fine emery cloth so that they meet 
squarely across the entire face — see pages 377 and 378* 

J^JJ^ ^^*^ ^^^-^Ijf^ Eef erring to lUustratlon flg. 2;— shaft which drives distributor 

dIMcfbiiUir and top rotor and timer. High tension current passes from distributor brush 

view •! timer. Timer (K) to spark plug terminals, A^ — is screw for setting position of 

toamnied under dit^ timer t-am. Note automatic weights or governor which automatically 

iTT. S7S and isS*) advances the spark. Fig. 5 is not automatic. See page 377. 

•^C» l«t tlie ttmer« tee pagea 250 to 358. 81S, &17« 300. 377, 37S. *8ea foot note bottom page 240, 
a&d page S7B. tA defective condenter auch as will cause contact trouble will cauie lerioui miating 
of the ignition. See also page 803, teating a magneto condenser. 

ffTba *'g&p-t7pa** distributor Is one used In flf. 5, because contact U not actually ma4«. \)»\l\. V<»&,\t% vtt 
tpark plug iHrraJnalt. (see also page 247.) A. brush type dittrlbiitOT is &« pet **B<sac>v;* ^j^^* *^^'^^ 



Circuit Ignition System. 

Tlie Atwater-Kent Open 
As an example of a modem battery and coil 
system of ignition, we will use the Atwater- 
Kent open-circuit system. (This concern also 
manufactures a closed-circuit system, as illus- 
trated on page 249, 250, 252). 

Parts: Consist of: (1) the distributor and 
timer, which is called the Unisparker; (2) the 
coil, which consists of a simple primary and 
secondary winding, sealed in an insulated cylin- 
der. The coil has no vibrators, contacts, or 
other moving parts; (3) the depolarizer switch; 
(4) the automatic spark advance. 

Tbe function of the Atwater-Kent system 
is to produce a single hot spark for each power- 
impulse of the engine, accurately timed to occur 
at the right instant to produce the greatest pos- 
sible power and efficiency. (See page 250). 

The timer shaft is a % inch shaft, driven 
housing; as shown in fig. 2, page 248. 

The timer shaft is a % inch shaft, driven 

usually from the cam- 
shaft and at cam-shaft 

speed. It is also quite 

often mounted on the 

generator and driven 

from it, as shown in fig. 

8, page 246. It should 

always be installed in 

the coolest location 

The contact points in the timer do not tonch 
except during the brief instant of the spark. 
The ignition circuit is therefore normally open 
and no current flows, even though the ignition 
switch be left '* closed." This dispenses with 
the use of a resistance unit, or thermostat as 
described on page 250, 246 and 254. 

The operation of the timer. This consists of 
a pair of contact points, normally open, which 
are connected in series with a battery and the 
primary circuit of a simple non-vibrating induc- 
tion coil. 

A hardened steel latch, against which the 
tri^jror strikes on its recoil and which in turn 
operates the contact points, completes the device, 
5*»c figures 1, 2, 3 and 4. 

The distributor forms the upper part of the 
Unisparker, the high tension current from the 
coil is conveyed by the rotating distributor block 
arm (DA), fig. 2, chart 117, thence to the spark 
plugs in their proper order of firing. 

Gap t3rpe distributor; the distributor arm 
(T>A) does not touch contacts above it, but 
passes close to them (gap l/50th in.) as it re- 
volves and the high tension current jumps the 
slight gap, therefore termed a ''gap-type*' dis- 

Figures 1, 2, 3 and 4 show the operation of 
the Atwater-Kent open circuit timer clearly. It 
will be noted that in fig. 1 the lifter is being 
pulled forward by the notched shaft. When 
pulled forward as far as the shaft will carry it 
(fig. 2), the lifter is suddenly pulled back by 
the recoil of the lifter spring. In returning, it 
strikes against the latch, throwing this against 
the contact spring and closing the contact for 
a very brief instant — far too quickly for the 

«Do not think that these parti do not work properly because you cannot see their movement. The contact 
maker of the Unisparker may be likened to a watch, which, because of the small size and extreme accuracy and 
hardness of its moving ptrts. is subject to very little wear. Don*t change tension of spring or alter parts. There 
are as Buuiy notches (lig. 1) In the timer shaft, as there are cylinders, and as many leads from the distributor 
to spark plugs, as there are cylinders. See lower illustrations, page 248, for parts of the AK open-citcwvl V\«v« 

eye to follow the movement (fig. 3).** Note 
that the circuit is closed only during the instant 
of the spark. 

Fig. 4. Shows the lifter ready to be pulled 
forward by the next notch. 

Adjusting AK Open-Circuit Timer. 

Adjustment of gap between contact-points should 
be .010", when lifter (fig. 1, above) is in the notch. 
This adjustment can be made by placing more or less 
thin shim washers (see W fig. 8, page 248) on contact 

When taking up this distance between points, due 
from natural wear, remove both screws and dress with 
a very fine file, then replace and shim up to .010". 
The points are made of tungsten steel which is very 

Remember that when points are working properly, 
small particles of tnngsten will be carried from one 
point to the other, forming a roughness and dark gray 
color, this however does not in any way affect the 
working of the points as the rough surfaces fit each 
other perfectly. Spark plug gap should be .025". 

The Condenser. 

The condenser instead of being in the coil, is 
located on the timer of both the open-circuit 
type, fig. 6, and on the closed-circuit type, fig. 4 
and 5 and fig. 1, page 249. Note the circuit on 
page 249. The condenser is arranged so that 
it short-circuits across the timer contact-points 
for reasons stated on page 228. 

To explain how the condenser is connected, 
see fig. 4, this is the metal cover which is placed 
over condenser to protect it and also to which is 
attached the insulated contact-point of timer. 

Fig. 6. C is condenser 
cover o n open-circuit 
timer. Fig. 4, cover of 
closed-circuit timer. 

This condenser cover is insulated from base of 
the timer by screws 5 and 6 which have insu- 
lated washers on them. 

— Continued on page 249. 


w^. » 

rouail je 
j.iC uaepeuii 

dutxidutor «£d 

d^. J. i: conauu 

T.:^ Ltd cocfiact 

:uai-;r. " which 

xiijr* Ari-roprUte. 

:.:.• tiin-r fhaft. 

tA':h. other. 

aj*r»ced in 

XLi\i •^.i>l;k«aelL on pftf« 

ftnd 7. 
i«*r th« 
I govr- 

s(i[irr lu; 

lU.- >- 


ft. Kurw-L Srw ?o«-:un ii nu -1 

n :z i.jir.i -:*4 :il« curr»Mi£ o :: 
~ -J.. - ^rtr-i^-ti^e iriag oni-r ji" '.. .. 
r^ ',. "a.-* fiAf:. The diitribnior ar-n 
* 7.u«Mn li* fcj?fc tension curr-nr ro 
1- «4-*f are re4«i«<* P**" ri?v.ji'i:.un. 
^■i .* i>:nl.'alor poinii ar< *pu..'-: . . -■ - 
... * »r--=vl coil with ■ Mcon ury A:ii 4 ; r -.i 
' 1-.*.- ' * ij1i»). tfommj from t:ie baicry j.- ^ 
" , '.• - ■•*=pnj iwiich throuj^h t:-i:-?r .■i;l.:.i.>. 
: . t^; :-:«u »i the proper tim^ l.y •.: - -■^: 
: ■- -vu-: »ith nctchei (N. «?■ 2 «1: .l; n.- ;. 
" ■• ■• Q which »re intuUted from ea^•^ — • 


-.=:-fr shaft 

k-L \i :^ with 


^■i- -T-ior fta- 

!i til'' time 
1 }{ j-'vemor 
::i:t a : at 
I'lr irm . Gl) 
Ujrks ii2i.>wn 

■••■.i^ <:t in 

•- is P-'J-intid 

'"T !.V ■■ With 

:!:».•> of the 

h:\ uoteheft 


■y winding. 
>u^rator is 

wli«*ro the 
: arm ' D) 

':atoh (E). 
CO come 

- . -iy^-c th* priioarr circuit m t;.' .0 i 1 ■. e oau<es a 
"^ ./*- «l UP in the ipronddry wiiid:::*: o! hitfj: voltage. 

- * . -# •I'tn distrihutird lo the spark ;.'jc« \: iho dis- 
-" .. ^-Ti" Vr* «»« no* used— iee page I'll* ) 

"- J^t^^»M (N) In the timer shaft as there are cylln- 
' "J t^:'^J'^^^^i^^*^^^^*'^ »•'"«• " *'-" "" oyhnd.T.. 

Polarity Switch. 

-*^ --T,-i If jswadad to prerent the points on (B and C) from 

-..*.-^ ■•^V\.?Lf ••nirfrf current is u«cd whuh ba^ a t.nd 

^ «-.-: aac f*:^"- j„j^^ whereas an alternating current i« much 

"■ ' ■ . * Tierifore to alternate the flow of curn^ni from N to 

. . X ir' ;^ii*:i:Ve 10 negative and negative to positiTe— is thv prin- 

• '' ' *w::rh. .^ ^^^ with all battery systems. 

*" ' f.^n one direction has a tendency to deposit the 

• ' * ■ ; T„ iVother— but by changing this flow of onrrvnt 

■'■.'. ''/..ofil^i" be Ptit b*«^k to the other point again. This 

- •.- ... iro-i' .witch- D is now flowing negative. A 

U.. .-•-.■'r ••• «'«,'?l;ri',;T?JS one q»"«" «»"• «''•»■«"• "' 

" ^ -.r^"»f°" """'*» •"■' '■•' ' ""*'■'"■»■ •" '""'■ """" 

V- .'v-Tenslon CoU and B»tt«y Opi-Circalt IgniUon System 


HEOttl tuned from p«(e 247, 
^ Note tlie termiAjOs A and B of condenser, 
IK. ^. Terminal (A) is jj^toujiiIpcI to base (C) 
€ff timer below it^ then insulated washer (3) is 
(>lAcod over (A), Tlie other terminal (Bj/has 
an ifisulnted washer (1) under it to insulate 
lerniinal (B) from base. Cov^er (4) is then 
placed over condenser and terminal (B) makes 
contact with cover. We then have one terminal 
(A) of condenser grounded to base (C) and other 
iHi-minal (B) coaneeted with cover (4) wMch 
is insulated from basa. The circuit would then 
be as shown in fig. 1, page 249. 

It Is fl«I4om n^cesB&ry to removo condenser, but if 
tffnlUoa falls In c&bo timer sbouJd becotue water Bomked, 
fwl of coil, with Bwitch on. it gboi^iUl «how sornc he«t 
fT<*m *iirr*nt t»^BBinff tKrougb reaigUnre unit in coll, 
rou wll! then know curri^nt ia paBnlng: tbrotigh the 
*oil ftllrffht, therefore open iwiteh. Then r^-move di*- 
tribator cover and con denier cover and clean all con- 
tacta and screws and replace condenser cVver, also 
wip« water from thft otIiPT pnrts and wires, Tlie 
Icnitiiiii max mXmo fall by theae screws coming loose, 
however, this rehkim happens but if if^nition falls, 
yet you know (be current is passine through the coil 
and no spark can be obtained, then this raight be 
inTe»t lira ted. 

OtL UBe Wsht n>n chine oil at points shown by 
tinea on open ci rent t timer, fig. 6. pare 247. 


If cngtoe mlSfes without regard to aposd, test rach 
rjriinder separately by nbort-circuitin;? the ping with n 
»e»«w driver, alloivine « fpark to jump. Tf all cylinder* 
produce a good, reffnlar spark, the troabte is not witli 
tine ignition. 

If say one cylinder sparks regularly, this will \n- 
dicste that the syi^tpm is in wnrkincr order ao far ss 
the Unliparker and cod are concerned* and the trotibte 
is probably In the high-teneion wiring between tbo 
distributor and pltigs or in the plugs them selves Kx- 
aniao carofully the pings and wiring. Leaky secondary 
wiring ia frequently tbo rause of misBlnjr nnd bnrk- 

rtMinently, when hlgh-tenalon wires are ntn from 
tho dlatrlliQtor to the spark plugs thi'ough metal or 
tbro toblng, trouble is experienced: with missing and 
teark'flring. which Is dae to Induction hetween Ui* 
vmiloQS wires in the tube. This trouble is especially 
I lilrely to tiappen if the main secondary wire from the 
roil to the center of the distributor runs throngh tbU 
tube with the spark plug wires. 

Wliereirer poaalble. the dlstrllimtOT wires shoald 
¥« B«iiarated by at leaat Vi lach of space and should 
bo anpported by brackets or insulators rather than run 
tlinrorta a tube In no case ihonld the main dlstribn- 
tor Wire be mn through a conduit with the other wires. 

If Irrafiilar sparking is noted at aO plugs, e:c- 
I amine first the battery and ronneciions therefrom. 
If the trouble commences niirbli^nly, it in probably 
dao to A loose connection in the wiring. Tf grad- 
oaTly. the batterie* may be weakening or the con- 

tact noints may require atteoiion. See that contact! 
are clean and bright, and also that the moving par 
«re not ^umired with oil or rusted. 


The wiring of the AK open-circuit Hjrstem 
shown on ptx^e 248. 


C°" PI 

Rotor Sets on 
fop of CAcm}>«ft 

Grounded eo Bu« 
IftHiUted Contact ^ 
Potm Cbftnect» 
With imulatfd 
Cbndenler Cove 
luulitcd Scrt^ t^ 

CoadenKT Covo^ 

Vent (m heat from the 
yiatu^ ftciuuner 


»1V4 V/'" ..»«*Jw* 





Fig I 

' BAT- 

-i OntTrrxn- 

^ Grounded 


^ ^^ One TcttH' 
inxl of 

Ban oT Tuner 


|«ru»er LVder 
G^ver, End A 
Grouiidedi Ejd 
B IhauUiai 

The wiring of tlie AK closed-circuit system, 
which ia the model €0, is shown above, also 
page 2')2 and explained on page 250, 

Tig. 1. Circuit of tlie AS clOBed'Clrciilt timer. Not* 
one wire frimi timer and one wire from battery la 
grounded, therefore it is a "single-wire** system. 
The open or closed-circuit system conld u«e either 
a ' •single" or "two-wire" lystem. 

To traco prtznary clrcttit, start at twitch, follow 
black line to Insulated terminal (4), then lo insulated 
contact point through grounded contact point to 
grounded terminal, to ground (T) to ground on battery 
(B). (Note condenser connects across ihe contact 
f (tointa). 

To trace secondary circuit start at Si, thence to 
distributor rotor, through spark plug to ground (8f) 
through primary wire to {82> where secondary la 
irronnrTed to primary wire In the coil. 

^Explanation of the Automatic Advance of Spark, 

♦♦Oovemor: The T>Ldcci and Atwater Kent 

L^*#tem5 employ a mechanical governor for ad- 

rvancing the spark when the engine is speeded, 

A governor of the centrifugal type is employed 

on both systems, but of sliphtly different con- 

itnietion. The purpose of the governor is to 

cause the timer notched shaft to turn in the 

direction of rotation, ciuislnpf the contact to 

make and break earlier as the speed increases. 

For instance: refer to f\^, 6. page 248. As- 

Lsuroe engine ia running slow and governor is in 

[retarded position. Xote position of notch (A) 

top of timer shaft. If enjjine is spee<!ed up, 

governor weights (GW) fly outward, causing 

nor shaft to turn further advance in direction 

rotation — it is clear to see that the contact 

ronld be made sooner at D and E (fitr. 3>. 

[The top of limcr abaft Is driven through the 

governor arm — see fig. 2. 

•Tho &dv»cee and retard of spark is explained under 1 
**Afwator-Eont supplies the Unisparker uiib or without 
aecondary wire. 

In addition to the govenior advauce^ — the 
distributor honaiiig can also be advanced by 
hand, the two working indepc^ndent of each other 
(sec ftg. 3), L is connected with spark lever on 
the steering wheel. 

The manual or hand control is for the pur- 
pose of securing the proper ignition control for 
carburetor adjusting, slow idling, retard for 
starting and variable conditions which cannot be 
held constant. 

The automatic spark control is for the pnrposd 
of securing the proper control due to variations 
in speed alone, and all that ia required for nor- 
mal driving is to secure the proper spark con- 
trol for slow driving from 10 to 15 miles per 
hoar (set the spark lever about % advanced) 
and tho automatic feature will give the proper 

gnition Timing — pages 305 and 807. 
governor. tUse /<'' outside dia. of Insulation for 



**The Bemy Ignition System. 

The Bemy ignition system consists of the 
combined timer-distributor unit, a coil and 
the switch (see chart 118). The system 
operates on thn closed-circuit principle, and 
is distinguished by the fact that it has but 
two moving parts — the cam and the breaker 
arm. The system is made for four-, six- and 
eight-cylinder engines. 

In operation, the rotation of the cam C 
brings, its comers in contact with a fibre 
plug which is riveted to the breaker arm. 
The arm thus is lifted, separating the con- 
tacts. Inasmuch as the moving parts are 
▼ery light and a considerable period is al- 
lowed for the saturation of the primary 
winding in the coil, both mechanical and 
electrical lag are practically eliminated. 

Only hand advance of the breaker mech- 
anism is provided. 

Whole mechanism stationary: Another 
feature of the Bemy unit is that the whole 
mechanism is stationary. Advancing or re- 
tarding the spark does not move any of the 
wiring. This is accomplished by mounting 
the breaker mecha-nism on a plate, ^he 
plate is attached to the advance lever and 
is moved with it, thus rotating the breaker 
mechanism partly around the cam. 

The distributor mechanism consists of the 
usual Bakelite cover, with the terminals 
molded in place. There is no wiping con- 

tact, the spark jumps from the radial dis- 
tributor arm to the terminals. Wear, there- 
fore, is eliminated. 

On top of the coil there is a miniature re- 
sistance coil in series with the primary wind- 
ing. This is to protect this winding in the 
event the engine should remain idle for any 
length of time with the switch closed. In 
short, it protects the winding and also pre- 
vents excessive drain on the battery. 

Bemy adjustments: Under ordinairy conditions 
the contact points, which are iridiom-platinam 
or tungsten should not require attention more 
than twice a season. 

They should he dressed with a fine flat flle to 
present perfectly smooth surfaces. 

The contacts should he adjusted with the 
wrench provided so that the maximum opening is 
.020 to .026 in. The rehound spring should he 
at Teast .020 in. from the breaker arm, when the 
contacts are at maximum opening. 

For best results the spark-pIng gaps should be 
.026 to .030 in. 

If the engine misses when idling or at light 
loads; the gaps at the plugs should be wider. If 
the engine misses at high speed or when pulling 
hard the gaps should be narrower. 

The oiler on the shaft should be kept fllled with 
medium cup grease and screwed down two or 
three turns occasionally. On some instruments 
a wick oiler is used. In this case use pure Tas- 
eline instead of grease. 

Manufacturers are Remy Electric Oo., Ander 
son, Ind. 

tWestinghouse Ignition djrstem. 

Battery and coil ignition system is of the 
dosed circuit type (see chart 118). It is 
made for 4, 6 and 8 cylinder engines. 

The timer-distributor unit is vertically 
mounted and is operated from the cam shaft 
or can be attached to generator, as all other 
systems of this type can be. Only hand op- 
erated advance is provided. 

The condenser is mounted close to the 
breaker mechanism, being below the coil and 
distributor. Note the condenser, coil and 
breaker are all in one unit. 

A metal ring can be slipped upward to 
permit inspection or adjustment of the con- 

The distributor is the same as that used 
in the regular Westinghouse systems in 
which a circular carbon brush make con- 
tact with terminals embedded in the cover. 

The standard ignition switch is of the 
snap type and combines the lighting 
■witches in one plate which is mounted 
flush on the dash. Each time the ignition 

The Connecticut 
Is a typical example of a closed circuit 
type and is made for 4, 6 and 8 cylinder 
engines. This company calls the interrup- 
ter and distributor, which is mounted in 
one unit — an "igniter." They also term 
the timer, interrupter, because it is similar 

*8«o charts 229-234 for ** Specifications of Leading Oars." for cars using these different systems. 
**8«« page 818 for example of timing Remy ignition on Chalmers. 
*8e« alto pages 846 and 848. tSee also, page 848. 

switch is turned the polarity of the cur- 
rent is reversed, therefore it would be 
termed a polarity switch (see chart 117 
for principle). 

Westinghonse adjustments: In adjusting the 
breaker the contacts should be dressed with a fine 
file and adjusted so that the maximum opening 
is .012 in. Spark-plng gaps should be .025 in. 

The distribntor brushes should slide freely in 
their holder and the spring should push the top 
brush out so as to extend from the holder about 
M in. when the distributor plate is remored. 

In the back of the switch plate there Is what 
l8 termed a "ballast coil" (for same purpose as 
"thermostat" — chart 119). This is a small re- 
sistance in series with the final winding, and i» 
to protect the winding and prevent excessive drain 
on the battery, should the engine remain idle with 
the switch in the "on" position. If this should 
be accidentally broken the ballast terminals may 
be temporarily short-circuited with a piece of 
wire or with a standard 5-amp. fuse. 

The only Inbricatlon required will be two or 
three drops of oil about once a month in the oil 
cup provided on the sid^ of the distributor unit. 

Manufacturers are Westinghouse Electric Oo.. 
Pittsburg, Pa. 

Ignition System, 
to a magneto interrupter — which interrupts 
the flow of current — however, other systems 
as the Bemy and other closed circuit battery 
and coil ignition systems also call the timer, 
interrupter, as it is exactly the same prin- 
ciple, (see pages 252, 254, 364 and 358.) 




r «f ''4inc%** cnirvat. Note this trpe of generator tmn 
rtiw b&t tW armalure ti alwayt DRUM wound with a com-^ 
StS^ 3S&. S33 for dram ftrmfttureft. 
t]rp« fttti crt pcrtB«o«ntlr mAgBetlted. They are c»Ued th« 

Art eteetricftllj ma^etiied ftad remAln mmg* 

H^«t potee. Tbii type of djaamo or g<&n- 

_ «f i or 9 rolt« and will light d«etrie tampi and 

■t fMr inltltft. It i* uiially run in conni^ciloa with a itartinf 

la «Md lor ifaHioa on itationarj and marine enfficiei to a con- 



llf* I* t%f Hagllrtt ti iii^ A a«c4«Alc*t goiMrator, but the current f^nerated ii "ftUematinf/* 
lK»t iiL tka ettrrvat ia sot a i N t id y S«v, Wt altortiates continQoualy. The field m»fnett are always of 
Iko panaafitat uft^aat l7f«^ TW afwatmro for ff*acratiac altematiof earr«<nt i* of two typat; the "shut- 
%lo** lypa at thown in nf*. 9 aad 4 or the ^^iaditct^r'* type aa thown in tg. 6. 

Tiko thatUt or "armatsra** t7F# •! ftimalsro (tee pace 274) haa a primary wire windinc of eopper 
«lr«^ oo« and fri>uaiJ<Hl lo armaturt eor* and oiher end iniulated. If there ii but one windlns on the 
aroiatare It it railed a ''primary" winding and ie of low irolUic« : about 6 rolU. Therrfore it it called a 
**tow teatlon" inafneto. If Ikere are two windinft on armature it it called a ^'btghteotioa" mafneto. 

Fig. 8! Uia *'lAd«Cter** ^M af anaaturo: Tlio wire la AtaUonarj and the icductort or ''rotors'* re- 
▼oIto, whereas on the **sliatUe type the armature and wire revolve. The latter type is more generally tited. 
*T)ia X. W. macncla ie a laadiac ntacaelo of the Indnctor type, Oonstnictloa; ms^eta, permanent type; 
pole-pieces places! above armature 90* apart; rotors si*t 90* apart. There are two rotors with 4 ends. Fig, 
I iUuttratei th«* arranffinent of retora tm armature thaft. This gires the same effect as if two thnttle 
armatorea were |ilaci*d rrott wit* — which would be 4 iropulfci per rev. (flg. 10) instead of 2 In the shotUe 
type <flf. 9>. If w** continued addioi we would soon have the altcroations so dote together we could light 
as electric Ump— in fact, the K, W, low teniion mag ncto at high ipeedi will accomplish this. 

Tlie ooU on Uko K. W. ia italltt&ary and rotora reyolve. With a single primary winding on coil core it 
ie a low teutioo cuagncto. With two wtnditigs, per page 268, flg. 6, is then a high-tenaion magneto. 

Fig. SA* shows linea nf forri* pasaing down through rotor wing from N pole» then centrally through 
eore orer which coil is placed, up rotor to S pole. 

Fig. SB, thows rotors mnvpd in poeltloa where lines of force are now passing in reverse direction, which 
eanies a complete reversal of polarity through eoll winding. This is marlmnm posltioa sad whore eon- 
lact points (P) should separate — see page 396, which It % high'tenslon type. 

Fig. 9: ShtiUIe, or ''armaliiro" 

tjpe magneto (see page 274); 

»|*^iflO*-^ producet 2 impulses or wave 

Tmpulic diigram. 

of current of ma^rimom intea- 
tity per rev. <360"), Note di- 
rection is changed each ^ rar. 
or 180* (see pages 26«. »6T). 
Fig. 10. The K, W. tndnetor 
type armattu-e produces 4 im- 
pulses or wavea per rev. Kote 
direction of flow of current ia 
changed 4 limes or at each % 
rev. or 90*. 


QBAMT NO. i:ao— Mechanical Electrical Generators of * 'Direct" and ** Alternating** Onrrmat 

'Bee alto pages 254. 288. 299 sad 082. 



♦LOW TENSION MAGNETOS: Construction. Parts. Princi- 
pie. Magneto Action. Explanation of Impulse and Waves 
of Current. Low Tension Ignition Systems. Inductor Type 
Low Tension Magneto. Ford Magneto Principle. 

We will now take up the "mechanical" 
•onrce of electric supply for the different 
ignition systems. 

A device for generating electricity me- 
chanically is called a dynamo or magneto. 
The kind of current the dynamo generates 
is "direct" current and the magneto gen- 
erates "alternating" current. 

The direct current dynamo generator is 
Dsnally called a "direct current generator 
or dynamo" and is usually applied to gen- 
erators run from the engine which supply 
current for charging the storage battery, 
for lighting, also for ignition. 

This type of generator can have either 
"permanent" magnets or "electro mag- 
nets" for the magnetic field, but in every 
uistanee, the armature is a "drum" wound 
armature. This type of generator gener-. 
ates a low tension or voltage, usuidly 6 

The alternating current generator is al- 
ways called a "magneto," because the field 
magnets are of the permanent qiagnet type 
and the armature is either a "shuttle" or 
"inductor" type. This type of generator 
generates nothing but an "alternating" 
current, suitable only for ignition. Alter- 
nating current will not charge a storage 

Alternating current generators are di- 
vided Into two classes; the "low tension 
magneto" and the "high tension magneto." 

We will take up the construction of the 
low tension magneto first, because the high 
tension is really a low tension magneto^ but 
with a double winding on the armaiore. 
Therefore, staxtinff with the low tension 
magneto first, it mil then be easier to maa- 
ter the prindple of the high tension mag- 
neto later. 

Magneto Construction — ^Low Tension. 

The inrlndFle of a low tension magneto Is 
similar In many respects to a low tenslcm 
coU as described on pages 215 and 214. In a 
magneto the armature on which the primary 
wire is wound is called upon to produce 
its ewn electric supply, whereas in a primary 
or low tension coil the electric supply is 
from another sonree. Bee fig. 1, page 260. 

nald magnets: Therefore, permanent 
magnets (la), called the "field magnets" 
are provided as shown in fig. 1, chart 121. 
The pole pieces (11a) provide a magnetic 
field for the shuttle type armature (fig. 4) 
to revolve in. End plates with ball bear- 
ings are attached to screw holes in pole 
pieces (11a, fig. 1). There is very little 
clearance between the armature and the 
poles, therefore accurate fitting is necessary. 

The mssBets; usually two, fonr, or six, are 
placed orer the pole pieces: all north poles on 
OSS side and all south poles on the other side. 
Tke liase (13a, chart 131), is usually made of 
hnas or aluiainum, as neither will become mag- 

The armature is explained in fig. 6, chart 
121. This has a dngle winding of coarse 
wire (nsuaUy abont No. 18, insulated), 
eaUed a "primary" winding similar to the 
primary winding on a coiL 

On a high tendon coil system, one end of 
the primary wire leads to a commutator or 
timar, and the other end to a battery. When 
the e&reiiit is elosed and suddenly broken the 
enrrent is ''indnced" in the secondary wind- 
ing as previoosly explained. 

Ob a magnslo, fha primary winding Is 
eloasd, and the sudden opening or "inter- 
mptton'' of the flow of enrrent in the pri- 

mary winding at certain times (see page 
267) intensifies the current. 

This interruption of enrrent can be accom- 
plished in two ways; by "brealiiag" the 
current with an "igniter" suddenly, as in 
fig. 1, page 260. 

Or by "interrupting" the current with a 
"contact breaker or interrupter" as per 
fig. 3. Therefore, we have two methods of 
intensifying the low tension current of a 
low tension magneto. 

The first method is similar in action to 
snapping two wires together as explained 
in fig. 6, page 214 and illustrated in fig. 1, 
page 260. The interruption is made by an 
igniter, operated by a cam on cam shaft. 

The second method is similar in action and 
is explained in fig. 3, page 260. 

It must be borne In mind that the tlma 
the Interruption takes place Is when fha 
annature is in a vertical position, for at that 
time the strongest current will be available, 
(explained further on.) 

The armature Is In a vertical position 
twice during one rovolntlon, therefore we 
can make two interruptions during one 
revolution, by having a "two point" cam 
raise the interrupter arm at the right time. 

If a single cylinder engine, only one nose 
on cam is needed. 

If a four cylinder, four cycle, we need 
4 sparks during two revolutions of srank 
shaft, therefore the cam would have a 
double nose and would run at the same 
speed as engine crank shaft. 

TUB tjttitm Is new seldom used, but must first be understood before reader can properly understand 

the Msh tsMiea mafBeto. 

'An lew tsadea mafnetoe are not driTon at fixed .spaed. See K. W., page 365. 


Flff. 6. A dynamo or mochanlcal 
hftTo either "permanent" or "electric 
mutator on end of armature ihaft. — s> 

Ponnuient magntti are of the ).••: 
"Held" magnet!. 

Electro field magneta are vm::.-: 
netiied only when armature r* \ < 1 
orator, generate* a steady "iiir<- 
recharge a storage battery ani! • 
and lighting system, and in ^ ■ . 
•iderable extent. 

> .ss«r 

^ by • 
... ihaft. 

TC of in 
v.'und on 

Fig. S— The low tenilo^ 
magneto complete. Vie ^ 
ihowa the drive »»nd of tb^ 
armature, which is driv*^ 
at a fixed speed from crao » 
■haft of engine, by jcear o^ 

The armatur*" has on^ 

.Mi^ *aurtie «yP« armaiur*. 

^dtitUe- or "H" lTr# 
M*uACur« core (C and i. 
'..So >r^na« heads. Wir* •♦ 

, »., » iiMid casting: rath.-r i 
* ♦ .auip*d a group o« ».• ^ 

'"!*\1 v.:o*»w >o ***• detail altf^.*^ 
**.«•». ** "t '• called, is t** -. 
'^ J*m •" *^* ^*"'* ***** '*■* " * 
"\\^u which are at play t» %> 
"if* :taeif. and If^ 
"** jio irmature unduly. \« »>* 
**^Ii» 'vnn the slight obaliw«*«v> 
„ «J»r.l them. 

. u^fcure la ahowu at (l>} Ia** 

'^ungo (C) being eoUa iVm^ 

* tacether. b«t«e«M «'«' 

Fig. 5. — Sectional Tlew of a low 
te&5ion magneto, showing one method 
cf conducting the low tension correnl 
Iroa armature; one end of primary 
%*.:;d:n.; whi.h is lio»»vy. coarae wire 

* ^rci::: l«.-l l«» urinuturo core at (O) 
r e o:h»»r on-l (A), is inmilated and 
: i9«!S it.rou);)! ti.i.' I.oilow i-nd of anna 
'.'i.T< .oh.ift aiui makeA contact with • 
V.'tst il>). I see also flg. 4. page 260; 
At I}-" aruinturi* rfvulvea. the spring 

S »hu*!i IS mount''<l on an insulate) 

' '.'* ■. IH». coniiutM.s the current 

.-. i''. .1 w>r«' conru?«'t»Ml with it. to 

.••••••.'»'. V ■V'oU'.il'jr rings." similar 

' .>-.*« on ti:e hi;;h tonsinn magn-to 
♦i 1 \^ .»•• 1 l*. i'»:;o 'JOS, are also 

terminal the current !• 
L* ■ sinter." as per fig. 1 

• ;« - . 

*'. « '.'. V<^ "otod that a separate low 
{^^,.^... .v.: :« uot necessary in this in- 

••.4.-.V. »» '. • ■ w •: lir.c on armaturf 

;"»j '.."w •-;»:•.■« .on magn^o is used 

«»•.<« » IV*!.' a: t:e !:ij(h tension coil, as 

I ^ : »; J ' .^ th»'n this wire A 

. . . « • .' I ico to the pri 



"Make and Break" Low Tensioii Ignition System; Using a Low Tension 
Magneto To Supply Electric Oorrent. 
Low tension magneto to supply current for the "igniter" as shown in flg. 1 
plained on page 259. 

(|!Q movable electrode 

and ez- 

up And ^oim 
Hot 1 en of rod 
opera t»d by 

FIf. 1^ — On* method f«r Intenilfyiiig the current 
fkem %kM low tension megneto ia to euddenly breek the 
flow of enxTent aa explained in flr. e, page 214. In- 
iteed of breaking the flow by hand, kowoTer, the make 
end break type of "igniter" ia need. A low tenaion 
eoil ia not need with abore ayaiem aa the winding on 
magneto takea ita place, (aee flg. 6, page 268. for 
namea of parte of magneto.) 

Fig. 2.— The low tension magneto ignikloa on 
a mnltlplo cylinder engine. Battory for stazttac. 
Magneto armature rerolTea same apeed aa crank 
ahaft of engine. 

Note that a low tenaion or aingle wonnd eoO 
mnat be need in the circuit if the battory ia 
need, whereas if magneto is switched on instead 
of the battery, the winding on the armature acts 
aa a coU instead. Note a cam shaft operatee 
the "make and break" igniters, whleh corera 
the time of spark, causing four sparks during 
one rerolution of cam shaft, or two rerolutions 
of crank shaft. 

On above system, armature is driven at a fixed speed, because it is of the '' shuttle 
l^rpo.^' The cam snaps the igniter arm (M) when p&ton is on top of compression stroke. 
Tneirefore armature must be in a vertical position, just leaving the pole (see pages 266, 267 
and 809). See also pages 257, 259, 261 for relation of speed. 

Vote— an low tension magnetos are not driven at fixed apeed — see K. W., pagea 264 and 265. 

A "High Tension" Ignition System Using a Low Tension Magneto to 
Supply Electric Current. 
This system is fully explained on page 269. It is similar in many respects to the bat- 
tery and eoil system described under Instruction 19, except a low tension idagneto suppliee 

the current instead of a bat- 
tery, and the 'interrupter and 
distributor are mounted on the 
magneto instead of being 
driven separate. The objec- 
tion to this system is explained 
on page 261. Also see pages 
261 and 2(9 
for relation of 
speed of armn- 
ture, distribu- 
tor and engine 
crank shaft. 

to ipaik vlugs 

Spark plQgt 

High tenjlOD / 
double wound ^ 



Ground ratum 


_ ^^^ system Is 

slightly different 
from the one 
ehown at bottom 
of page tea. 
where the Inter- 
rupter or eeataet 
breaker ia shunt* 

Ttg, S. — Another method for intensifying the current from a Itfw tension magneto, ad aeroes the pri- 
is to use an ^Intempter mounted on end of armature shaft and connected with a sop- mary e I r e u 1 1. 
arato high tension coU, without ribrator. In this instance a high tension enrreni would Witii above sys- 
be proTlded in secondary winding (8) of coil by current produced from the low ten- tem it is In 
slon magneto when primary circuit is Intorrnpted at maximum position of ammture. aeries. 

Switch . 

OBAXT HO. 122— Two Slmpllfled ISettaods of Using a Low 
method of abort eireuiting magneto; switch is closed to cut off magneto. 
'iatempter" and "oontaet-breaker" moan the tame. 

Note in flg. 8, 



The annatnre revolves, therefore the end 
of the armature primary winding (B), from 
whieh the low tension current Is taken, is 
carried through end of armature shaft (in- 
sulated), similar to D, flg. 6, page 268, but 
where an interrupter is on armature it is ar- 
ranged similar to K, fig. 2. page 270, but 
not connecting with anj other part than 
the wire from armature. This spring eon- 
tact conveys the low tension current from 
armature, whieh revolves, to primary coil 
winding F, flg. 3, page 260. 

Note Arrangement of intermpter on psge S70. 
It is a different conitmction from flg. 8, page 260. 
The interrupter on page 270 is more modem. The 
one need in fig. S, page 260 is aimplified. 

The current is then carried through pri- 
mary winding P, to insulated term&al B, 
through interrupter points P (which open 
when armature is in maximum position), to 
arm A to ground G, back to magneto ground. 
This completes the primary circuit of mag- 
neto and high tension coil. 

Magneto Distributor Parts* 

Trace arrow points from upper primsry wire 
from magneto armature, back to magnete grouid 
for the primary circuit. 

The secondaxy current (fig. 3, page 260), 
starts at distributor brush (D) to msulated 
part of spark plug, jumps the gap, thence 
returns from metal shell of spark ping, to 
<< ground" connection on engine to second- 
ary and primary connection on eoil (S-P) 
through secondary winding (S) back to dis- 
tributor brush (D). 

Magneto switch (fle. 8, page 260) is open when 
the magneto is working, but to stop the magneto 
from generatlsg current, the switch is dosed or 
"short circuited." A glance at the UlustratioB 
will show how the armature is short ciremited, 
therefore "interruption** of current cannot take 
place — see also page 275. 

The magneto mnst be driven at a fixed ipe«d 
because the interrupter and position of armature 
govern the time of spark. Therefore, the mmg- 
neto is either drlTcn bj a chain or a gear from 
the cam shaft but not by belt% see page 295. 
"magneto speed.*' 

*The pnzpoBe of the "high tension" dis- 
tributor is to distribute the high tension cur- 
rent to the spark plugs. The distributor 
brush (D) ought to be making contact with 
one of the spark plug leads just as the in- 
terrupter points are breaking. See page 
296 explaining connections to distributor. 

Distributor is usually attached to the mag- 
neto — when operated with a magneto, either 
of the low or high tension type. 

The distributor Is usually made of hard 
rubber insulation material with metal seg- 
ments (see page 268). The rotor with 
brush revolves by means of a gear wheel 
twice the size of gear wheel on armature, 
(flg. 1, page 269.) 

Armature for a four cylinder magneto, 
would rerolve at engine crank shaft speed 
and make 4 sparks during the two revolu- 
tions of the crank shaft. 

The distributor however would revolve 
once and make 4 contacts during two revo- 
lutions of the crank shaft — hence reason for 
larger gear en distributor. 

On a six cylinder engine the armature re- 
volves IVs times to one revolution of crank 
but distributor is geared to turn one-half 
the speed of crank shaft, or one complete 
revolution to 2 revolutions of engine crank 
shaft, (see pages 306, 295 and 294.) 


contact arrangemeots 

gap-type* ' as explained on 

' the "brush type*' as 

There are two kinds 
on a distributor; the 
pages 247. 245. 812, and 
per flg. 2, page 259. 

It mnst be remembered that while we are re- 
ferring to the magneto distrlbntor of the trne 
"high tension type magneto*' — to show the psrts 
,of a "high teniioa distribator" — ^the distributor 
used with the low tension magneto and separ- 
ate coil (page 260, flg. 8), differs only — ^in that 
on a true ugh tension magneto — there are two 
winding! on armature which takes the place of 
the separate coil. 

Low Tension Magneto and High Tension 
With a Battery to Start on. 


The system described in chart 122, flg. S, 
which uses a low tension magneto In connec- 
tion with a high tension coll, Interrupter and 
dlstdbntor, would not be satisfactory — for 
the following reasons: 

The magneto is a mechanical source of 
electric supply. In order to produce elec- 
trie current, it is necessary to revolve the 
armature. When the armature revolves, cur- 
rent is generated, but if revolved slowly the 
current is weak. Therefore it is natural to 
aaeume that by merely cranking the engine 
by hand very little current will be gener- 
ated. For this reason, a battery is provided 
to start on, as the source of supply is then 
eoastant; no matter if engine is cranked slow 
or fast. 

After engine is started, then the switch 
is placed on the magneto side and the mag- 
aeto supplies the current to the high ten- 
sion coiL 

would then be called a 
Meaning a dual or second 

Ignition system is added, but using the same 
set of spark plug^. 

There are two ways of using a battery to 
start en, in connection with a low tenkoa 
magneto; one method would be to have a 
separate high tension "vibrator" coil, com- 
mutator and battery, as per chart 124. 

Another method would be to merely add 
the battery as per chart 123. 

With this latter system, there is but one 
high tension coiL The only addition to our 
system flrst described in fig. 3, chart 122, 
would merely be a battery. 

This, of course, would require special con- 
nectiens and be rather complicated, but will 
be made perfectly clear if reader will refer 
to chart 123 and study it carefully. 

The system described in chart 124, la la 
reality a true '*dual" system, because there 
are two separate and independent ignition 
systems, but only one set of spark plugs. 

The system shown in chart 123, however, 
is simpler and was formerly extensively used. 

It is ased for the same purpose as ^ ^ _ 

to. ilstrlhato h^h tengUm current to the spark-plugs. 

dl stel b atei — althouah in this instenee it it placed on a 

osod on a high tension magneto — ^pas« ^^% — '"^^ ^^^"^ ^ 

*\ow Xv^mVon.** 




COllVCRM '*'*••-: 



nw ecus R)8 smmNft 

Michigan Low Tension Magneto 
and High Tension ColL 

Th» pszpoM of those UlBftrafctoiit. ia to iliow 
kow tho IntoRvptor on the macnoto- can also per- 
form tkis fuction for tlie batterj, which has been 
added to the system. Note that the current from 
the macneto is connected to contact (19) of the 
coil box. 

We will now briefly outline the path of the cur- 
rent from both sources, and trace them from start- 
ing point, all the way through and return, flg. St. 

Battery drcnit: When switch blade (X) on coU 
box is on the battery side, the path of current 
woald be; from the 4- side of battery, to terminal (2) — then to contact (8) through switch to (4) — then 
through primary winding (6) to ground conneetion (6) — thence to ground terminal on coil box (7). 
From here it leads to wherever the coil is grounded (in tlie illustration it is shown directly on the mag- 
neto, at 8). Now as the interrupter arm (A) is grounded also, it follows that current will flow to it. 
then through breaker points, then to B. 9, 10 and on to negative terminal (11) of battery. 

Magneto drcnit: After engine is started the switch is thrown over to magneto side, this cuts out 
the battery, and current will then be taken from magneto, which is a low tension type. 

Beginning at the terminal (18) on magneto, the path leads to terminal (19) on coil box — thence to 
contact (20-21) through switch (X) to (4) and then follows the same route as the previous current np to 
ground connection (8). Now since one end of armature coil is grounded, current will flow through it 
and to starting point. 

It yet remains to be explained, how the interrupter performs its duty. Notice another contact (21) 
close to contact (20). Switch lever (X) connects these two contacts and thus opened another path 
vhereby current reaches contact (28) thence through circuity to (9) — then to contact (B) and breaker 
points, to (A) whenever the cam is in such position as will allow points to be in contact 

Starting on ignition: Sometimes, the engine can be started by pressing a button on "starter 
switch.*' (see flg. 25) a few times in rapid succession. This button is represented in the diagram as 
(22) and is mounted on a spring tongue, which, when pressed in, makes contact with (OB). The switch 
will have to be on battery side of course, and current will be made and broken by the pressing in and 
releasing the starter button. One of the pistons must be in the right position and ready to flre. and most 
usually is; about seven out of ten times. A charge of gai must also be in that cylinder. A charge of gas, 
or part of a charge will remain in a cylinder quite a long time if rings are tight and precaution taken to 
draw in a full charge by opening throttle and speeding engine Just before it stops. 

The high tension circuit from secondary winding of coil is shown in flas. 23, 25. Condenser, not 
shown, is connected around interrupter points per page 274, but is in the coil, per below. 

Splltdorf Model D Low Tension Magneto and Ck>ll System. 

Sputdorf dual system — using a low tension magneto and high tension ooll with battery to start on 
and magneto to nin on: The contact breaker on magneto is utilised for either battery or magneto sys- 
tem. The primary circuit through armature however, must be opened to prevent battery from de-mag- 
n.ti>inc the magnet, when battery i. u.ed. „^^ „„^j, ,^„ ^ ^ ,,„^^ ^,,4, (^. 

through connection (0) to primary wire of coU, 
through ground 01 and 08i to armature. The 
breaker points (P) it will be noted arc connected 
or shunted across the magneto primary circuit. The 
circuit proper, is throngh armature and circuit 
breaker and the coil primary winding receires only 
the kick of the armature (extra current) when eon- 
tsct points open. It will be noted battery circuit is 
open at switch. 

Battery drcnit: switch blade (W) should now be 
on B side connecting the two terminals, and magneto 
terminals on (M) side are open. Ourrent traTols 
from top of battery to switch point, to primary wind- 
ing of coil, to ground 01 to 02, thence through in- 
terrupter points (P) to (lower connection) battery. 
Note armature is ent ont entirely but not Interrupter. 

High teoslOB evmnt ia distrlbnted from secondary 
winding on coU to hnA (B) ea dl itrl b alo r, thenee 
to spark ping center electrode, thenee throngh spark 
gap to plug shell ground (0) of anglne and frame 
back to coil where primary and secondary connect. 
Condenser, althouch locsted in coil, if circuit is traced it will ba obatrvad thai It ''bridges*' the points 
t lTv«k»'r ju»t tie Mme as on page 274. See puge 278 for principle of magneto coadenser. 

aocxt TerMcwF at XAatOTo 

of .ort 

imAIlT JfO, 123— A Low Tension Magneto with a High Tension OoU— wttH flM AtfdlUon of a Bat- 

i€ir to Suppljr Camait to Stan wIUl After engine ia started the ■Mgaeto supplies the 

curreot. (MicbigMn Srstem fonnerlT used on IBLefaVN. ttfittbtaf Soal P ' 



a&rx'* viadia^ or law teaflioD armaturfr, Dli 
lor, diitdbotfii rurrent for thft ''coil myti^tD** 
"mjkgntto ftjftlem^* indeperndenU;. Not^ raAf- 
brnte H gToxta^ed to frftm«. 

li iyit«]n» the title wlilcb La glvftn undiiz tbii 
la the cytteai f omiflrly uied en older modeli of 

Paektrd. Altlioiigli it Is ont of date, we ihow 
as ao egample of how a low -teniion magneto li 
tn eonnectiozi with a high tension coil for one 

m and a high tension ^oil and battery it nsed 

he teeond system, thereby forming a "dnal sys- 

)f ignition." 

• low tension current from the magneto enters 
primary winding of the magneto coil fig. 2, at the 
P. R^ and leaves it at post P. M., returning to 
nagneto through the "ground" Ton will readily 
rhat an important part the wire connecting post 
:. with the screw on the rear cylinder has to per- 

It is the common path for all of the current of 

e high tension current thus induced in the sec- 
ry winding of the magneto coll (flg. 2), follows 
ly the same path as described in connection with 
high tension battery current from post *'B" 
igh the distributor arm and piste of the mag- 
to the respective sparlc plugs, and back again to 
ugneto coil through the "ground" and post P. M. 
leneTer the engine is running, the magneto is do- 
ing current, ft only passes through the magneto 
however, when the switch is thrown to magneto 

With the switch in any other position the cur- 
ia grounded without passing through the primary 

e intermpter mechanism of the magneto is located 
e end of the armature shaft (lettered "make and 
:") ought to have been lettered "interrupter," 
interrupts the flow of current, 
e coil box in the center of the dash contains two 

Each con is a Complete unit in itself. The right 
coil, flg. 8. is for battery current, and is fitted 
a single vibrator. The left hand coil is for mag- 
current, and has no vibrator, 
a switch has three positions. Turn to the right 
tattery, turn to the left for magneto current, and 
to a vertical position for neutral (no current), 
he upper side of coil box are four binding posts: 
'. brings low tension current from the battery. 
^ brings low tension current from the magneto, 
'anamits high tension current from both systems. 
. is a common ground wire for both kinds of cur- 
from both systems. 

e low tension current from both ihe battery and 
•to, though of good amperage (volume), is low 
tttage (pressure). The two coils receive from the 
ry r magneto their respective low tension cur- 
and deliver currents of high tension. 

• battery and coU system: is used for starting the 
m, and for reserve. There is a storage battery, 
i also provides a low tension "direct" current. 

7/i-.^ g^'.~,t^ /K^r^ ^, 

f^' f ii> 

Fig. 2. High tttudon 
eoil without Tibrator, 
used with the "magneto 

Fig. S. High 
coil, with Tibralor, used 
with the "eoil and bat- 
tery" system. Note 
the commutator is used 
with this system, bnt 
not with the magneto. 

The battery current passes through the battery eoil, 
flg. 8, and the contact for this battery and coil is made 
by a "commutator," operated from the cam shaft. 
This practically makes two systems of ignition using 
but one set of spark plugs; therefore, it is called a 
"dual" system ignition. 

The battery and coll primary current; starts at the 
poaitive pole of the battery, the current follows the 
connecting wire to the post on the coil marked P. P. 
At this point it enters and passes through the primary 
winding of the battery vibrator coil, fig. 3, coming out 
again at post marked P. M. and along the eonx^ect- 
ing wire to the ground connection on engine frame. 
The only path by which it can return to the battery 
is through the contact shafts and roller to one of the 
binding posts, and by means of the metal connecting 
strap to the wire running to the negative terminal, the 
circuit being complete at each time the roller in the 
contact box passes over one of the metal contact 

The high tension current: Whenever this low ten- 
sion circuit from the battery is completed, as above 
described, a high tension circuit is induced in the sec- 
ondary winding of the battery coil. The high ten- 
sion current leaves the coil at post "B" to the central 
postr at the top of the distributing plate on the mag- 
neto, thence to the distributor brush, which roTolves 
to the left (see flg. 1). 

The current then travels through the distrfbvtor 
brush to segments, thence to spark plug connected 
with segment on which the distributor brush makes 
contact. The secondary current returns from metal 
shell of spark plug to "ground" and back again 
through engine frame to post P. M., thenpe to the 
battery coil, flg. 3. 

The battery currant ii gensrafted by ehaaiical aetlMi, 
and is ready to flow the instant the circuit is completed. 
It is, therefore, particularly useful for * 'starting on." 
It is only necessary to break the circuit to stop the 
flow of the current. 

The vibrator operates only when the low tension 
current is passing through the primary winding of the 
battery coil. 

Ckmdenser in coil flg. 2, protects Interrupter points of 
magneto and in flg. 8. protects coil vibrator pointa, 
or both. 

-Example of a '*Daal" Ignition System; employing a "vibrator" eoil with batterj 
and eoil "without vibrator '' and low tension ''magneto'' to run on. The one 

T NO. 124— Example of a 

to etart on and eoil "without vibrator '' and low tension "magneto' 
distributor on magneto distributes the high tension current to the spark plugs. 
*hart 126 omitted (error in numbering) 


niufltratiozi showing how a high tension coil is 
used in connection with Remy low tension 
magneto. (<}— ground.) 

Tig. 4: TlM K. W. low-tension magneto used in 
eonneetion with a master-ribrator coll. 

The Bemy Low-Tension Inductor 
Type Magneto (Model B L). 

The principle is similar to the K. W. flg. 8, page 
256. except the Remy rotor is e half-rotor^ whereas the 
K. W., both ends of rotor are utilised. The Remy pro- 
duces 2 impulses per rer. and the K. W. 4 per roT. 

Fig. 1 : Bemy roton (L) which rerolTe and the sta- 
tionary single primary winding. 

Fig. 2: Bemy indnctor or rotor in inaiiTniim posi- 
tion, similar position as fig. 8B. page 256. 

Fig. 8: Bemy contact-breaker. The points (P) 
should have a clean surface. Dirt and grease should 
not be allowed to accumulate. 

If engine misses with spark retarded at slow ipeed, 
adjust the contact screw (B) out a few notches. 

If engine misses with spark adTanced at high speed, 
adjust the contact screw in a few notches. 

On above magneto igniton system adjust spark plug 
points .025". 

The contact-breaker is used on this magneto just the 
same as on a shuttle type magneto armature; to inter- 
rupt the flow of current in the primary winding. 

To time the armature, place rotors just the same as 
a shuttle type armature. 

The EL W. Low-Tension Inductor Type 
Magneto and Blaster- Vibrator. 

Fig. 4: The K. W. Indnctor type of low tension 
magneto, used with a master-vibrator. Dry cells as 
a source of supply for starting when switch lever is 
on the left, or (B) side. Magneto is used when switch 
is on (M) side. See page 280 for ''master- vibrator." 
Also page 256, flg. 8, for inductor type of armature 
used on this magneto. Not#the vibrators on dash coil 
are short circuited, per flg. 2. and are not need on the 
multiple dash coil to the right, as the one vibrator on 
the master-vibrator coil does the vibrating for the 4 
coils — see pages 280 and 265. 

The Oscillating Type Magneto. 

Figs. 1 ft 2: This type is a regular shuttle or arma- 
ture type masneto and is the original magneto prin- 
ciple, designed for slow speed engines. The armature 
does not revolve but oscillates back-and-forth from posi- 
tion 1, to 2 (80*). 

It can be nsed with an Igniter arangement, flg. i, 
which is similar to flg. 1. page 260 — except the igniter 
rod is actuated by lever (L) on magneto, which is 
tripped by trip (J). It can also be used with a mag- 
netic ping as shown in flg. 2. 

The Magnetic Plug. 

Flg. 6: The principal parts of the magnetic ping are, mag- 
netic coil 5, pole-piece 2, interrupter 20 and contact piece 
on plug shell 21. Plug is screwed into cylinder. Prlndpls; 
owing to sudden flow of current through coil (6). the upper 
portion of hammer bar (1). called the armature, is attracted 
to pole-piece (2). which effects a quick separation of contacts 
20 and 21 producing a spark at these points. 

Flg. 4: ninstrates how the magnetic ping is nsed in con- 
nection with a low-tension magneto (type ^K4*' Bosch) wltk 
a rerolTlng armature, with a main and auxiliary winding, 
one being a continuation of the other, and a distributor for 
connections to the magneto plugi. This system is termed the 
Honold system and is for 2, 8, 4, 6 and 8 cylinder engines. 

trtp W*f 



Uagnetie plug 
used with low- 
tension oscil- 
lating type 

OHABT KO. 120— Inductor Type of Low Tension Magnetos; one giving two impulses per revolution 
the other (flg. 4) giving four impulses per revolution. The Oscillating Type Mttgneto. Magnetic 
JPhig, Bee page 924 for Remy magneto circuits. 

IS5. 127 mad 128 omitted (error in numbering). 



*Iiow TmuAtm liagneto with "Inductor" Type of Armatim. 

In the fore^ing matter we have dealt 
entirelj with the low tension magneto using 
a ''dmttliB" type of armature with its pri- 
mary winding, all of which revolves between 
the magnet poles. 

There is another type of annatare called 
the ''Inductor" type. This armature differs, 
in that the primary winding, flg. 1, chart 
126, remains stationary, whereas, the induc- 
tors (L) revolve; principle is explained in 
chart. This type of armature generates 
"alternating" current of low tension, and 
must be connected with an interrupter, when 
used with a coiL In fact, the same prin- 
ciple is used as with the shuttle type arma- 
ture. It gives two impulses per revolution. 
The voltage is of low tension or about 6 

Another type of "inductor" annatiire to 
that shown in fig. 1, chart 126, is used in 
the K. W. low tension magnetos. This 
armature is illustrated in flg. 8, page 256. 
Note the inductors are similar to the Bemy 
shown in flg. 1, chart 126 — except the K. W. 
uses both ends of rotors, whereas Bemy one 
end, but rotors 180* apart. Instead of the 

inductors or rotors on the EL W. being 
placed so that two impulses are given per 
revolution; note the position and method 
the inductors are arranged. With this ar- 
rangement, the inductor cheek would break 
from the pole of magnets every quarter 
revolution. Therefore, there would be four 
positions when the current would read maxi- 
mum, or four impulses or sparks per revoln- 
tlon (figs. 9 and 10, page 256). The volt- 
age of primary winding is about 6 or 8 volts. 

This type of magneto is shown connected 
to a "master vibrator coil" system as per 
fig. 4. chart 126. The speed of this arma- 
ture is about 3,000 revolutions per minute. 
It is not geared at a fixed qpfeed as the 
shuttle type armature, but because it gives 
twice the number of impulses per revolu- 
tion, and by running it at a very high rate 
of epeed, generates an alternating current, 
the changes taking place so rapidly, it is 
almost continuous. tThis is one tsrpe of 
alternating current generator which would 
nght lamps and operate with a vibrator coil, 
but it would not recharge a storage battery. 
A storage battery can only be charged with 
a true continuous or "direct" current. 

:^The Ford liagneto — an "Inductor" Type. 

Another form of a low tension magneto 
with an "inductor" type armature is the 
Fotd magneto. The Ford magneto gener- 
ates a low voltage also, of about 6 volts or 
slightly more, owing to the speed.** The 
current generated is "alternating." 

This is also caUed an Inductor type of 
annatare because the coils of wire called 
the "stationary armature," remain station- 
ary and the inductors or magnets called the 
"rotating field" revolve. 

Instead of there being two impulses per 

revolution, there are sixteen impulses per 
revolution, because there are sixteen coils 
and sixteen inductors or magnets. 

In other words, each revolution of the fiy 
wheel, to which the magnets are attached, 
means one revolution of the crank shaft. 
There are 16 positions of the magneto when 
the current output is at its maxlffium height 
and each of these positions is called the 
peak of the current wave. There axe^ also, 
16 positions during which no current la fiew> 
Ing at alL Each of these is called the neu- 
tral position and each is half way between 
two peaks. Therefore, every sixteenth of a 
revolution of the magneto a position is 
reached when no current is being gener- 
ated and are termed "dead points." 

Each alternate peak Is of an opposite 
polarity; that is, there are 8 positions in 
each revolution when the current flowing 
from the magneto winding to the spark coil 
is positive and between these positions are 
8 other positions when the current is nega- 

Belation of the Low Tension and High Tension Magneto. 

We have now dealt with pnctlcally all of 
the low tsniion ^rpM of magnetos in general 
use. The true form of low tension magneto 
from which we will produce a high tension 
magneto, is the type using the "shuttle" 

armature, which revolves between horse 
shoe type, permanent magnets. 

The high tension magneto which will be 
treated In instruction No. 22, is merely a 
modification of the above mentioned 
tie" type armature magneto. 

*No(«— -These syitema are now seldom used for sntomobile werk, but are shown in order to siTo 
tke reader ilia information and to brinf out the less understood points. 

**8aa the Feed finpylamant pares 805 and 770. for * 'relation of speed of Ford magneto to Tollaffo 
generaled." tThe FOrd Indaeter type magneto wm light lamps and supply eurrent for a Tibrater type 
ceo, bet voltage Tariea considerably. The Ford magneto will not charge a storage battexr. beeause the 
ewrem geserated is alternating. A rectifier ia shown on page 809, which could be used with a Ford 
magneto, but ia not altogether practical. 



Tb« c*ait Aa tlie rhsDKe (aIem pUc« twice dur* 
ing ooe revoliitioQ of tbe armature it it neceuAr? 
that ft two point cam be used on the contact^ 
br«ftk«r io ord«r to breftk contftct twi6« durixLt 
ot)« reTolotioii — tee pmfet 257, 2S9 and 261, 

To »#t tha magneW: Ai ■tatcd, the point ftt 
wbkb the armature cheek i« juat breakiniif from 
the pole is the corred povtUoii to aet tho magneto 
anaatiir* — and at the aaaae time the luterniptar 

How Gurrent 

4 pefmanciit magnet it made of hard ateeil a&d 
re tain a it a magnet iam* Its magnetic inlluenee ex* 
l«Ddi from one pole to the other, which la called 
the magnetic field as ahowD in fig. 2. 

polnta ahodld |aat aeparata — both operatloni ahomld 
occur at the aame ioatant, (aee page 809.) 

Advancing and retarding: Theee cama made of 
iteei are in a caaing, and hf hikvlng thia eating 
made ao that it can be moved through aaj, the 
one-tenih part of a circle — the time of the inter- 
ruption of current can be advanced or retarded 
with relation to movement of armature. Thia 
meana the spmtk wlU occur early or late, relative 
to movement of plitona. (lee page 309,) 

l8 Produced. 


Tie flLafiietlo U&ea of force alwaya flow N iaio 8 
pole. If a bar of iron be placed between the 
polea (NAB), or io the magnetic field, fig. 3, the 
aagnetie linat of force will travel freely tbrough 
Ike iron, it will be an eaater path, becanae the 
atr gap between polea offer 2B0 tlmea the re- 
eittance aa doei iron. The magnetic lines will 
alto be greatly increased. 

Therefore a aoft iron armature core, curved, lo 
It will revolve freely but aa close at poaiible to 
tbe pole piecei (soft iron also), ia placed between 
tbe pole piecea of the permanent magneia. A coit 
sf insula t(Kl copper wire la then wound on tbe H 
•e«tion of armature core — see fflg> 4. 

Gutting Lines of Force. 

If a piece of copper wire in the form of a closed 
[oop» ia moved down quickly past the pole of a 
magnet, it will cut the tinea of force down and a 


rigt. 6, 7: In bMa poattion the coll la cntting 
tbe greateat nomber of lines at right angles — the 
lines have followed an eaaier path and are paas- 
ing through the ends of srmatnre core: — none 
through center or tbrough coil — the generation of 
energy haa ranched ita maximum and ia atored 
in the wire— the actual tflui in the core is now 
at sero. The thing |ha| is moat important ia. 
not the amount of nkx that ia flowing through the 
eoil at any instant that is of importance to the 
generation of current but rate at which this flux 
is made to pass from one path to the other as it 
chsngea from out of coil into it again. Therefore 
from position 6. when alt flux la out of core or 
center of coil, to position 7, when the flux starts 
to pass through core or coil in an apposite direc- 
tion (fig. 7) represent! the greateat rate of change 
and ia the time for the contact pointa to open, at 
which time, is the practical maximum position. 

Tig. Bt the Unea of forca (ftnx) are now paas- 
ing through armature In a reyerse direction to 
what It did la fig. 5, but voltage pol&rlty ia atSll 
same direction, because the L A E aide of coil li 
sttll cutting linea of force In tbe same dirfiction — 
but as coil is cutting a less number of lines, the 
e. m. f. weakena aa it travels io xero position again. 

Hg. 9: Armature baa turned y, revolution. XTo 
lines are being cut, voltage (e, m. t.) strength la 
at lero. but current still axifta without genera- 
tion — -due to tbe storage capabilities of the arma- 
ture windings. For inatance. if we conaider the 
magneto as a sort of pump and reservoir on abort 
circuit, we can see why the reservoir can be full 
even though the pump has stopped. 

The reader mast bear in mind that there are 
two phenomena in connection with the magneto; 
one ia the voltage peak or maximum voltage flg. 
20. and the other is the current peak or maxT* 
Tanm current fig. 30. Tbeae two peaks are not 
in unison. The current pe^ak lags behind the volt- 
age peak aa much as 90^, when armature geta ap 
to apeed. Thia la the reason why there is a strong 
current flow even though the voltage wave la at 
zero. As armature moves from poaition fig. 9, tbe 
same cutting proceeds as bf^fore, but as the R and 
L aide of coil will now cut lines in an opposite 
direction, the voltage polarity will bo in opposite 
direction for the next half revolution. 

•A peimuient magnet wUl retain its magnotinn a long time tf a kaeper la kept on ends of polaa— see 

page 303. The armature on a magneto, when in a horiiontal position acta as a keeper — see page 302. 
An elactro magnet ia a magnet eonaisting of an iron core around which ia wrapped wirew When 
direet current ia pa«fled through wire tbe iron cora becomes a magnet — if flowing in one direction. Soft 
iron corea are used, aa it quickly loses its magnetism when current ceases flowing. 
tiCafnetie flux is tbe total nomber of lines of force flowing throuch a magnetic eircntl. 

momentary current is 

Senariled in the wire, 
owing say, from T to 
S, ana if connected to 
a galvanometer (O), 
needle will be deflected 
to one side» from sero. 

If wire is moved up, 
cuting tines of force 
up, another momentary 
current will be gener- 
ated in the wire but 
in an opposite direc- 
tion, from S to T, and 
Btedle will be deflected to the opposite side of lero. 

The momentary induced current is greatest 
when wire ia movad ao aa to cut the magnetic 
Ibaas Qt force at right anglea — applying this prin- 
cdpla to the coil of wire on magneto, tbe coil 
voirld be cutting tbe greatest number of lines of 
force when in position 6 to 7 — or when it is mov-" 
lag at right angles to the lines of force. 

The electric current In the wire depends npon 
the £, M. F. (electro-motive-force) causing It to 
fl<>» — therefore E. M, F, is geoerated in wire when 
it ts made to cut the linea of force, and a cur- 
rant flows when it is complete, due to tbe gener- 
atad B. M. F. Tbe faster the coil cuts tbe tinea 
—greater will be the E. M. F. generated. 

The generated E. M. F. alio depends Qpon the 
•trength or quantity of magnetic lines of force; 
tbe speed or rate of linea cut per second; the 
mmbvr of wires cutting the linea — therefore sev- 
eral layers of wire are used on the armature. 

Bcferrtng to fig. i, the coll la not cutting any 
of tiM Unas of force — the lines are paaaing freely 
through armature core from N to S— therefore e. 
&. f. (voltage) strength ia at aero. 

rig. 6: The L side of coll la starting to cut 
the lines of force up, and right side of cotl (&> 
la cutting down^E. M. F. is gradually increasing 
la eoiL Lines flowing down tlirough core N to B. 



Fig. 1— Dl»«Twa Of Connections of a High Tension M»gn«to. 

Kia«i of Pnndpftl Puu* 

BW — SteoDdAry winding of 
Wlf« Wt tiio PW primnry 

O — OoJI^^ctor ring. P^ — Brush 
OArrylng high tension cnrrent 
10 tbe b»i« of dittributer 

fhe cnrrent U then distT* 
,„li«d to the four pli 
dletrtbuter mm, { 

liuttfd to the four pluga throngh 
dletrtbuter mm, <Z> ** **- 
lermlnAli (T> 

S£~i« the iperk gnp. J— 
OoidtB««r. @ — it tninlAted 
kM« of diJitribntef. 

ice Ohnn 180 for otirer 
MJii. croii lectlon of which 
W !)• leen in Fig 

Fig. *2 — Longltndlnnl Section Ttiroiigb High Tension Magneto. 

gHABT NO. 129--Pilma^ and SecondAiy Circuit of & High Tcnxloii Magneto* Armature 
as a compound type^ meaning double wound. It rovolves with its wire winding. 
»ol«->Tlic dletHbutor bmeh <Z> Le retolTed ty o geer <W) wkioi !■ revolved by o gear (X> on umnti 

fCkmrU J 27 mod 129 omitted (TtOT in ounboring}. 


[THE HIGH TENSION MAGNETO, Description, Construction. 
Parts, Combination of Dual and Double Systems. Wiring 
Diagrams. Leading Magnetos. Four Ignition Systems on 
one Engine. 

The high tension magneto is not only a 
mechanical generator or a aubstitnto for the 
battery, but combines all the elements of a 
complete ignition system, except the pings 
and switch* 

It performs three separate essential func- 
tions as follows; generating current; trans- 
forming the current to a high pressure; 
distributing the bi^h tdsloii current to the 
IndiTldual cylinders. Besides these main 
functions, a number of minor functiona 
have to be performed. The high tension 
magneto differs from the tow tension mag- 
Aito in only a few particulars. 

Armature winding: The armature on the 
high tension magneto is wound with an ad- 
ditional winding/ called the * * secondary wind- 
log,'' whereas the low tension magneto has 
but one winding called the primary winding. 

Instead •f using a "separate*' high ten- 
don coU, this second winding on the anna- 

^tnrt of the high tension magneto takes its 
_ tac«. (See figs. 1 and 2, chart 12 9,) This 

[ secondary winding ia carefully insulated 
from the primary winding, except at one 
end, where both it and the primary wind- 
ing are grounded. (P W) ia the primary 
winding, and (S W) is the secondary wind- 
ing (fig. 2). One end of (8W) is lod, care- 
fully insulated, to a collector ring (0) 
mounted on the armature shaft, and a eor- 
bom pencil or brush (P) rubbing on this 

collector ring takes off the secondary eor> 
rent and leads it to distributor brush (Z), 

The other respect in which this tn># de- 
fers from the low tension magneto in that 
the condenser which is employed in oooneo- 
tion with the interrupter is usually built 
into the high tension magneto (J flg» I) 
whereas with the low tension magneto, the 
condenser is in the separate high tension 
coil. The condenser is usually, though 
not necessarily located on the armature shaft 
in order to get it as cloae to the interrupter 
as poeaible, and it is there shown In fig. 
If chart 129 (J). In some magnetos, for the 
sake of greater accessibility and other rea* 
sons, the condeiiser is located outside the 
armature in a stationary sealed bOE* 

The purpose of a condenser in explained 
in chart 109. 

Owing to the fact that the secondary 
coil of the high tension magneto is located 
on the armature itself it follows that it 
not only receives an induced current, due to 
the breakage of the primary current, but it- 
self induces a current kke that of the pri- 
mary coil, but imaller in volume. 

It has the same form of armature, field 
magnets and priudple of interrupter as the 
low tension magneto, but varied eonstrue* 
tion. The armature-coil, however, is differ- 
ent, having a primary winding with a see- 
ondary winding over it. 

« Construction. 

The high tension collector ring (Q> per- 
forms for the high tenaion current the same 
function that the spring (8) at the end of 
the armature shaft ia fig. 5, page 258, does 
for a low tension current. That is, in this 
instance, it conducts the high tenaion cur- 
rent from armature to the distributor. 

The collector ring is Uard rubber with a 
brmes ferrule (0) surrounding It, against 
whieh ferrule a heavily insulated stationary 
earbon pencil (P) bears. The hard rubber 
, spool has wide flanges for the purpose of 
kpreventing the high tension current from 
escaping, by giving it a long path to travel 
from the brass contact ring to the shaft. 
Am hard rubber is much more resistant than 
aiTf the current tends to travel over the 
surface of the spool instead of striking 
through it. 

««The distributor: It has already been 

explained how the high tension current ii 
induced in the secondary or fine wire wind- 
ing of the armature at the moment the cur- 
rent ceases in the primary winding. It re- 
mains to explain how this high tension cur- 
rent is distributed to the four spark plugs 
of a four cylinder engine in succession. 

The beginning of the secondary winding 
(9 W) (figs. 1 and 2, chart 129) is con- 
nected to the end of the primary winding 
at (N), and since one end of the primary 
^7]rdiug is grounded, the secondary is also 
grounded through the primary. The end of 
the secoodary winding leads to an insulated 
contact ring (0), fig. 2, at the driving end 
of the magneto. 

From this ring the current is taken off by 
a carbon contact brush (P). From the brush 

*FoT exiunpl* of m high toDsion miifQeto, tbe Bo«cb, t]rp« DU4 ma tbowa in chsrt« 129 sod IBO ii u»«d. 

■«ThU type of dUtrlbntcr Is the "bnifh' 
la th« Btrlmc pmgB S12. And exi 



typey aa it mak^t ft wipiny eontftct. Tht *'fftp-tjpe** It 
in«a on page 247. 


Fl£. 1 BOBcti "DUi'* Mgh-tonsloa mitf- 
neta for a 4 cyt engine. Note tiQ^Te Type "DTJ6'* it the ftfttne •z* 
copt for 1 6 cyl. engine. Type "04** 
hni 8 bftr m^ijnetg; Type *'DR4'% 2 b»T 

Pl£. 2. Front Vl«w of Boeeh **DfJ4" 
Xntermptor Parts. 

A — PlHlinnm point on inintaled contact- 
broaker block vrblcb co&ne«ti with 
ona end of prim&rf winding. 

B — Ftatinuni potnt on grounded breftker 
arm €. 

C' — OontttCt- breaker arm; plalmum point 
it on« end and Ing at other end which 
comei in coai«ct with cmm G at C 

I> — Brasi diac faitened to armfttnre ihaft 
and rotates with it. A. B and are 
f&ateaed to thii disc and revolve 
with it. but A la ineuLated from D, 
while B and O are groonded to ti. 

E — Carbon bruah grounds D ta magneto 

F — Oylindrleal hreakar-boz hooalng which 
can be ah if led by L. to advance or 

O — 0am bloeka which canse arm to 
ieparato pointa at A and B. 

H — Spring keepi pointa A and & clot«d 
until soperatea by G, 

K — ^Oonneota wltb A. or one end of 

Srimary and connects with terminal 
I ( jtisulniefi) , 
M' — Oonneeta with awltch aa ■hown is 
flg. 1. page 260. Other aide of awitch 
11 grotindad. When twitch It closed 
mAgneto ts '*olf' \ See page 275: 
**lo out off magneto." 
h — Spring for holding cover in place. 

Distributor Parta. 

T — Terminal to tpark plugt, 

Z — Diitributor bruth connecting with R. 

K— ~Oonnccft with pencil bruth P on 

collector ring 0, throngh contact con 

daelor Q, at per page 26l4, flg. 2, 
U-^egmentt or contact piecei connected 

with tortninala {T) on tryiich bmih 

(Z) alidet 

Flic. 3. R«ar SecUoDat View. Note aafety-apark-gap Z2 — tee 

alto, fig, 1 and 2, page 208. Note polo-piefea aerewed to end 
of field mitgnelt. The dark ihaded f*ArX oti armature repretetita 
secondary winding; light thading, primary winding. 


,BT NO, 130 — Names and Location of Parts of a High Tensioii Magneto* (Boseh.) 




Met the current Is carried through a spring 
contact conductor (Q) to the central di»tri- 
butor contact (B), 

The distributor coniiista of a disc of in- 
filiating material (S), in which are imbed- 
ded on the inner Bide one central cylindrical 
coLtact-piece (K) and four aonular aector- 
•haped contact pieces (U U U U| fig. 1, 
chart 129). 

Thd diatributor also compriscB a shaft 
(V, fig» 2), which carries a gear wheel (W) 
taething with a pinion (X) on the arma- 
tore abaft. The gear wheel (W) haa twice 
the Bumber of teeth aa the pinion^ and 
the distributor shaft (V) therefore makes 
one turn while the armature makes two* 

matilbiitor speed: The reason for driv- 
ing the distributor at one-half the armature 
■peed is as follows: The armature as al- 
ready stated, turns at the speed of the en- 
gine crank shaft. The magneto here de- 
scribed is for a four cylinder^ four cycle 
eDglne. In such an engine each cylinder re- 
quires a spark once in two revolutions of 
the craak shaft. 

The distributor is therefore geared so 
that it makes one revolution to two revo- 
lutions of the crank shaft and establishes 
eonneetion between the high tension or sec- 
ondary winding of the armature and the 
•park plug to each cylinder once in every 
two revolutions of the crank shaft. 

The gear wheel (W) carries a brush hol- 
der (Y) containing a carbon brush (Z), 
which is adapted to make conlact simul- 
taneously with the central distributor con- 
tact (B), and with one of the annular dis- 
tributor contacts (U).** 

The dlBtrlhutor sectors (U) are surrounded 

at the inaide and outside by annular rings 
of a highly Insulating m ate rial ^ since they 
carry the high tension current. 

Each of the four annular contact segments 
(IT) has secured to it a binding post (T) 
oa the face of the distributor disc, and 
each of these binding posts is connected 
by a high tension (highly insulated) cable 
to one of the spark plugs. 

There are numerous methods of taMng 
the current froni the secondary wladJug 
on the armature, but in the Bosch a car- 
bos brush pressing on an insulated ring 
is ad opted r thus allowing the annature to 
rotate freely, and also enabling the induced 
current to be drawn off. 

The distributor is, in effect, a rotary 
switch, especially insulated and provided 
with a number of contacts equivalent to 
the number of cylinders on the engine. 

Magnets and pole pieces: In any stan- 
dard magneto made on this principle the 
general construction would be as foUows: 
The field magnets consist of two — or usu- 
ally three — pairs. One magnet of each pair 

being superimposed above the others. (See 
fig. 3, chart 131.) 

In some few cases three magnets are 
placed one over the other. The magnets 
art sot to give correct north and south 
polarity. All north poles on one side and 
all south poles on the other side. 

The ends or poles embrace **pole pieces" 
of soft iron bored out to allow the armature 
to rotate *|uite freely^ but very closely to 
the pole faces; in some cases the clear- 
ance is only .00 2 inch. 

She armature: Consists of an armature 
core of soft iron of Il-shaped cross sec- 
tion; also referred to as a shuttle armature. 
This core of soft iron serves to form a 
bridge for the- magnetic fiux between the 
polo shoes, and also to carry the winding 
in which the current is induced. 

The armature is, in practically every 
standard type of the well-known **8hllttle** 
type. The best class machines have the 
armature built up of thin stampings of 
soft iron^ each insulated from the other 
by a thin film of varnish. This form of 
eonstrucdon is known as a ''laminated 
armature core. * * A laminated armature 
core is shown in fig, 6, chart 121, and a 
complete armature wound with double wind- 
ing is shown in fig. 1, chart 131. It has 
the advantage over a solid cast-iron core 
in that the electrical efficiency is higher 
through the absence of *'eddy*' currents 
in the iron core which represent considera- 
ble waste of energy and cause beating. 

By breaking up the core into thin sec- 
tions, the currents cannot circulate through 
the iron, (spoken of as "eddy currents,'*) 
In the case of a solid core^ the iron would be 
annealed to render it as "soft" as poi 
sible, to obtain the uest magnetic effect. 

ArmatTixe wliidliig: The armature core 
is first insulated with mica or similar ma- 
terial. Then it has several layers of heavy 
insulated wire wound upon it. To the end 
of this heavy wire is connected the begin^ 
ning of a very ine wire (No. 36 or 40)* in- 
sulated with Bilk, which ia wound on the 
core until the slot is filled almost to the 
height of the cylindrical portioui after 
which a wrapping of insulating cloth is 
applied f and bands are put around the clr 
cumferenco of the armature to prevent 
the wire and insulating material from fly- 
ing out and coming in contact with the 
pole shoes when the armature is rotated at 
high speed. To the ends of the armature 
the steel shaft or spindle is fixed by brass 
end plates. (See fig. 6, chart 121.) 

It will thus he noted that there are reaUy 
two windings on the armature whereas the 
low tension magneto has hut one wlniUiif 
— an inner winding of relatively few turns 
of heavy wire, and an outer winding of a 
large number of turns of fine wire. 

*Th4» wiodiof o( a Botch DU 4 niA^eto uitLillj co&itUta of 8 Uy^n of No. 21 iainlftted prlmAir 
virv moA 70 to 73 layeri of No. 86 lilk eover^ lecondftry wire. 
**B— fAot not* bottom of piKe 26d. 


^Ball ^Ge ar Drives Distributor . ^^^ ^^„^ ^^ ^.^^ Fig. 1 

Fig. lA 

Tig, lA. Interior vtew of a^bava atrmaturfl, reduced lu size. EC — on« 
«Dd of primary wtncting ifn:>unded!. The otber oad of primary wind 
lag" connecta with condentar (note one end of condooaer ii pround- 
•d, tea alao pa^e 268), th«nce the primary wlndlniE t«ada to the in- 
•ulated icrow. This aerew connecta with the maulBted breaker- 
point (A> and with «wUch conneetione <K) and (M), fkgi 2, page 
270. See bottom of pa^e 273 explaloing the prfmttry circuit. One 
•nd of ■econtiCaiT wlndljig connecti to eoUeetor ring. Other end 
IToanded to primary wire. 

Fig, 1. Exact Blza of a 
douple-wouud hlgb'ten" 
sion compoimd armatnra. 
It is eimilar to the low 
tension armAture* flg. 4, 
pag« 268, except tba ^ 
low tenaion annntora iftJ 
alngle-wootid. Tba gaarl 
which dritea tha dlatributor isi 
vbowti Kt one end and the eotlee^ | 
tor ring at the othor end. Wind- 
ing ia tapad and thallaeed an 4] 
■mall wira ban da plaeed aronad lt.J 

Tig* 2 — FhotograpMe Tivw of tba circuit- braakan^ or Inter- 
ruptair, on the oppoiite end to collector ring. Bama type »« 
ahown in fig. 2, paga 370, except interrupter arm above re- 
YoUei cloek'Wiia and fig, 2. page 268 reTolTes anti*eloekwlie. 

P tempter or Olrcnit-Breaker. fiCagnot Structure. 

Fig. 3— TIta horia-aboa magsata, 
pole pleca>. ate. are the tama 
principle ai naed on a low taniion 

riff. 4. Gircult open ait 
intarraptar. Thla ia tba 
time the apark occura. 
Note O raited by cam O. 

Tig. 6. Oirenlt cloiad on 
lnt«rTupt«r. Note O hat 
paeted over O. Sea pag« 
273 for explanation of 
intermptar, JL. B« and 
D rarolva (Anti-eloek* 
wiaa). F and G ara 

Compound Wound Armature. Magntlo Ia^ 



♦♦Condenser principle: When the two con- 
tact points (A and B) are auddenlj aep- 
arated there is a tendency for the eurrent 
to continue to flow across the gap, it pos- 
sessing a property similar to the inertia 
of matter. This would result in a hot 
spark being formed between the contact 
points, which not only would bum the points 
away rapidly, but also would prevent a 
rapid cessation of the current, which as 
already explained, is necessary in order to 
effect a rapid change in the lines of mag- 
netic force through the armature and a 
high inductive effect in the secondary wind- 
ing. To obviate this effect a condenser (J, 
figs. 1 and 2, chart 129) is employed, which 
in the Bosch magneto is placed in a hollow 
of the armature end cover at the circuit 
breaker end, also see chart 132. 

Condenser constniction: This condenser 
consists of two seta of tinfoil sheets, sheets 
of opposite sets alternating with one another, 
and being separated by sheets of insulating 
material All the sheets of each set are 
metallically connected, and one set is con- 
nected to the conductor leading from the 
primary winding to the stationary contact 
point (A), while the other set is grounded. 
In other words, the condenser is shunted 
across the Intexrupter. Bee fig. 1, chart 129 
and fig. 6, chart 109. 

Such a condenser is capable of absorbing 
an electrical charge, and its capacity is so 
proportioned that it will take up the entire 
charge of the extra current produced when 
the contact points (A and B) separate; that 
is, the extra current, instead of appearing 
in the form of a spark across the gap be- 
tween A and B, passes into the condenser 
(J). In this way the objectional arcing or 
burning at the contact points is avoided and 
the current flow in the primary circuit is 
more quickly stopped. 

fThe safety spark gap principle: There 
remains but one point to describe, and that 
is the safety spark gap (see Z A ZZ^ fig. 
2, chart 129). This is practically a safety 
valve for the high tension current. If, for 
example, a wire became detached from the 
sparking plug or from the distributor so 
that the ordinary path of high tension cur- 
rent was barred, there would be considerable 
danger of the current forcing a circuit 
through the insulation of the armature, and 
thus doing very considerable damage were 
it not given some easier escape as provided 
by the safety gap. 

A magneto must bo so designed thAt it 
will give a sufficiently hot spuk at a com- 
paratively low engine speed, and the abiUfy 
to do this implies the ability of generating 
very large and hot sparks and enormously 
high tension at high engine speed. 

The actual electro-motive force or tension 
produced in the secondary winding is, how- 
eoBJioeted or grounded to the frame. (Study e\er, limited by the sise of the spark gap 
fig. 1, ehmrt 119.) in the spark plug, for as soon as the ten- 

*The breaker polnto on th« BoMh sre urasUr set .016 in. gsp. ipark ping gsp .020" to .026". 

the vohwe ef tpsrk ah^i tw tlmM--flae slio page 229. Se« psgt 8Q%« 
tSee elfo. psgM 299. 291. 

Tho winding of heavy wlre^ or pri- 
mary winding, serves primarily for gener- 
ating the eurrent, and in connection with 
the fine wire or secondary winding, it also 
serves for multiplying the pressure or vol- 
tage to such an extent that it will produce 
a spark at the gap of the spark plug in 
the cylinder. Types of annatores are shown 
in chart 132. 

Tho Intenrnptor, also callsd a "contact 
breaker." To aeeonq>lish this breaking 
of the primary circuit at the proper mo- 
ment and then dosing it again, a device 
known as a circuit breaker or interrupter 
is used. This is carried on the armature 
shaft opposite the driving end. 

It consists essentially of a stationary in- 
sulated contact point (A), (see fig. 4, chart 
ISl) and a movable contact point (B) on 
one arm of the bell crank (0). Both of these 
parts are mounted on a brass dise. (D), 
which is securely fastened to the armature 
shaft and rotates with it. 

The stationary contact (A) is insulated 
from the supporting dise (D), while the 
movable contact (B) is in metallic connec- 
tion with it, and the dise (D) is grounded 
to tho frame of the magneto by a carbon 
brush (E). (Bee fig. 2, chart 129.) 

The circuit breaker is surrounded by a 
eylindrieal housing (F), to the interior sur- 
Hnt of which, at diametrically opposite 
points, are secured steel cam blocks (G A 

Ordinarily the two contact points (A and 
B) are kept in contact by a spring (H). As 
tiio disc (D) rotates, the outer arm of the 
ben erank (C) comes in contact with the 
earn blocks (G), whereby the contact points 
(A and B) are separated momentarily.* 
(Fig. 4, chart 131.) 

As soon as the end of the bell crank 
(0) passes cam block (G) the spring (H) 
br&gs the two contact points (A and B) 
together again. (Fig. 6, chart 131.) 

The stationary contact block (A) is con- 
neeted with one end of the primary wind- 
ing of the armature, through a screw pas- 
sing through the center of the armature 
shaft (See (I) fig. 2, chart 129.) 

The other end of the primary winding 
has metallic connection with the armature 
core; in other words, it is grounded. 

It win now bo readily nnderstood how 
tlM eisrent flows through the primary dr- 
eoit (fig. 1, chart 129). Originating in the 
primary winding (P W, fig. 2) on the arma- 
ture, it flows through the contact breaker 
screw (I) to the stationary contact (A), 
thence across to the movable contact (B), 
from which it is led through the contact 
bmsh (E), into the metallic framework of 
the magneto, whence it returns to the begin- 
ning of the primary winding, which is also 




^r Another almpllfied Illustration of m mgjb. Teaiioii Magneto Ignition System, thowing 

tho circuit of the primary wire windiBg on the armature and its conEection with the 
interrupter. Note the condenBer ii "»himted" across the interrupter. Another view 
iJiows the distributor and spark plugs and connections. Dotted lines represent the earth 
or ground conncctioD to frame. 

T& £if>rt^t^vr9>f 

Fff/MAI^r IMW^-V^ 





Sfi&^/^A/fy it¥iW4?//^(f 

Pic. 2, PrimAfV Armature, Single Wound. Figr 3. Compound Arinature, Double Wouud. 

Magneto armatures may be classified in two groups, according to the basic principles 
employed in the magneto field to gene rats the initial electrical impulses^ These axe known 
as the ABMATURE type ajid the INDUCTOR type. 

Armatnie type. — ^Elcctrical current is generated in the armature type magneto by 
revolving several thousand feet of fine copper wire, which is wound around a soft iron 
core, between the pole pieces of the magneto. As the winding rotates within its narrow 
confines, electrical impulses are Bet up within the winding. 

The armature tvp>e magneto may be redivided into two classes. One is called the 
PRIMARY ABMATURE magneto, and the other is called the COMPOUND ARMATURE 

The primary armature typ« has but a SINGLE winding in the magneto field and 
generates a low valtage cur^e^t and is described in Chart 120 as the LOW TENSION 

The compound annatnre type is the DOUBLE wound armature described previously 

The inductor typo of annaturo is a little different from the armature previously 
described. This type consists of revolving a solid steel shaft, upon which are mounted 
two steel, fan-shaped inductor wings, within a stationary winding in the magneto field 
(Chart 126.) 

In this type the wire does not revolve or move as it does in the armature on the 
magnetos previously described. The fan-shaped wings and shaft revolve, while the wire 
remains stationary.' 

This type of magneto 'requires a separate high tension coU (transformer), which 
is placed separate from the magneto, as shown in Chart 123; therefore it would be 
called a low tension magneto with a separate high tension coil. 

The type of magneto using the Inductor type armature is the BEMY and K. W. make. 

CMAST ira M^S^^JUioitbsr DiRgTMm 9t ft m^ Tension Magneto Olrcnlt. Magneto Armaturei. 




•ion raaelieft a point sufficient to jump this 
gmp the diflcbitrge occun^ aad there ib no 
further increase in the electro-motivQ force. 

* Suppose however, that tlie temxliials of 
the Epark plug are by chance bent unduly 
far apart, or that one of the high tension 
conneetions to the irpark plug accidontaltj 
comee loose, then there would be no chance 
for the vpark to pans in the ordinary way 
and the electro-motile force in the teo- 
ondary winding^ might build up tP ^^^^ ^^ 
extent as to puncture the inaiilation of the 
winding which would ruin the armature* To 
avoid this the safety spark gap is provided. 

Safety spark gap coilstnictloii: It con- 
sists of a Uttle chamber formed on top of 
Ihe armature cover plate with a top of in- 

Bulaling material. Into the top and bottom 
of this chamber, spark terminals (Zl, ZS) 
are set. 

The spark termiiial in the bottom is, of 
course, grounded, and that in the iniulated 
top is connected with a high tension con^ 
tuct brush (P) by a strip connector. 

The gap between the two terminals (Zl, 
Z2) is longer than the gap between the 
spark plugs, and ordinarily no spark will 
pass between these terminals, but if ow« 
ing to the conditions already mentioned, no 
spark can pass at the regular spark plui^ 
and the electro-motive force in the sec^ 
ondary winding attains an abnormal value, 
a discharge will occur at the safety spark 
gap^ thereby preventing the secondary elec- 
tro-motive force from rising still higher. 

Miscellaneous Details of Oon^tructlon. 

Some of the mechanical detaila of the 
magneto may be seen in charts 129 and 130, 
whieh are three actual views of the Bosch 
model DIJ4, It will be observed that a 
spring-pressed contact brush (a, fig* 2, chart 
129, extreme bottom) is placed in the base 
cf the magneto bearing against the circum- 
ference of one armature end plat^. The 
cbject of this contact brush is to make 
absolutely sure that the revolving metallic 
parts of the magneto are at all times in 
good metalHo connection with the station- 
ary part and the frame of the car; in this 
construction, therefore, the armature bear* 
lugs carry no current. 

The annatare shaft la taonnted In annu- 
lar ball bearings (fig. 2, chart 129) (b and 
c), which are provided with oil guardf m 
that any lubricant supplied to them will 
not be easily lost or reach the insulating 
parta. The armature tunnel is closed on 
top by an aluminum cover (i) and the 
front of the circuit breaker housing is pro- 
vided with a brass cover (g)» which is held 
in place by means of a hinged iat spring 
(h), 80 it can be removed and replaced. 

The distributor shaft Is mounted in ■ 
plain bronze buahed bearing, which is lu- 
bricated by means of a wick oiler (e). A 
fait washer (d) enclosas the inner end of 
the bearing, while at the distributor end is 
provided a channel (j) for the escape of 
any oil working out of the bearing so it 
will not reach the dlatributor. A large si-ze 
oU well (o) is provided for the wick oiler 
and is closed by a hinged cover (f) on top. 

A number of other Ulustrationa are alao 
ahown of the Bosch DUi magneto, in chart 
130 and 131, which may aid those not fa 
miliar with mechanical drawings to grasp 
the arrangement of parts. 

So far as the above description of Ihe in- 
dividual parts and their functions is con- 
cerncd, that applies to any true high ten- 
si on magneto, that is, a magneto having 
both a low tension and a high tension wind- 
ing on the armature. 

Each of the elements here described is 
always present, and serves the purpose indi- 
cated, though the relative location of the 
parts varies ao me what. 

To Cut-Off the Magneto Ignition— Tho Switch. 

It is neeeaaary to be able to stop the 
magneto from producing sparks when it is 
desired to stop the engine. (See fig. 
^f P*g« 270). To this end a sheet metal 
strip (K) is provided which contacts with 
the stationary contact point (A) of the 
eircuit breaker and leads to a binding post 
(M) on the circuit breaker housing. From 
Uiia binding post a wire is carried to a 
■witch on the dashboard. One side of this 
switch is groanded. 

When the switch is closed the current gen- 
erated in the primary winding of the arma- 
ture flows to contact point (A), thence 
through strip (K)» binding post (M), and 
connecting wire to the switch, whence it 

•B«latlOD of spark j^lng gap to engine Gompreasloa: A^sumiu^ we havo a 4 cylinder masneto. tbe 
•*»*f(»ly MP" ot which is set at %" coTvesitoading to 8000 volU, which aUo corresponda to the 
voH«f« required to Are a ipark plug having & g&p .025" under a preiauro of 65 lbs. If this magneto was 
r^kQiijfed to art an 6n^ifi« where there wan a higher Gompre«ston of 85 to 00 lbs,, ercn if the mix 
lure raprffiented ■ligblly lower reslitance. it wti^old probably fall to ire and iniiead, would jump 
•cTOia at the aafety rap (see Zl and Z2. fl^a. 1 and 2. page 266). However, a att^ht reduction of 
the dialance between the apark plni; points would lower the i^fTeciive presaare ao that il would operate 
In the proper manner. On the other hand, if the engine had low compreeslon, the apark plug polnta 
ahtrold be opened up. but if too wide, Ihia j^-ould immediately place a ^eater atrain on the apark 
plttf iaanlation and if the plug earboniied badly it would be apt to Hath over. Bee also, pages 817. 
S91, 390 and 303. 
ISpai^ plo^ gap and compression: For blgb compretaion engines 75 to 80 lbs., set gap .020''; for 
Itaaa. compreaaion en^inea 65 lbs,, set gap .036" ; for low compreaaion engines^ 55 Iba., aet ca^ Jim 
page 627 for rompresiioa. 

passes through a wire into the framework 
of the car and returns to the beginning 
of the primary winding. The effect of this 
is that the primary winding is *' short dr- 
cuitod'' all the time and the opening and 
closing of the contact points (A and B) 
have no effect* In technical terms, the clr- 
ctilt breaker la cut out. 

The flow of the primary ciurent can eas- 
ily bo followed in the diagram of connec- 
tlona (fig* 1, page 268) where its direc 
tlon when the magneto is working regularly 
is indicated by full arrows, and its return 
path when the magneto is running but not 
producing sparks, is indicated by dotted 




Fig. 1— A ''Single" high tension magneto; 
Engine is started direct from magneto cur- 
rent. Current is distributed to plugs. The 
switch connects to interrupter on magneto 
on one end, and '* ground" on the other. To 
stop magneto, the s«v^itch is closed, not opened. 


Fig. 2— A "Dual ' systam of ignition; 
Either the high tension single coil with bat- 
tery (using the distributor on magneto) may 
be used or the high tension magneto alone, 
may be used. Only one set of spark plugs. 


Flf. 8.— Bosch "X>ouhl«** System of Xnitton two stU of 
Spark Pings and two .Znd«p«nd«iil Ignition SjstMis. 

The "Double" system of ignition; 
high tension magneto and a separate 
single high tension coil with a sepa- 
rate timer and distributor combined, 
using a battery. 

The positive terminal of the bat- 
tery is grounded and the negative 
terminal led tc terminal ^6) of the 
stationary switch plate. Switch ter. 
minal (1) is tnen connoisted with 
the binding post located on the 
under side of the timer-distributor 
(T D). The second binding post on 
the timer-distributor, which is lo- 
cated on the under side of the tim- 
ing control arm, is to be grounded. 

Sir^iteh terminal (2) is connected to 
the grounding terminal of the mag- 

The cover of the Timer-Distributor may then be replaced, but a careful note should be 
made of the distributor terminal with which the distributor brush is in contact. This dis- 
tributor terminal should be connected to the proper spark plug of the cylinder with which 
the distributor of the magneto is in circuit. The remaining distributor contacts should be 
connected in accordance with the firing order of the engine, and wUl, of course, be identical 
with the connections of the magneto. Switch contact (4) is then to be connected to the cen- 
tral contact of the timer-distributor, and this will complete the connections. 

When the switch is In the off position, the battery circuit is broken and the magneto 
is grounded, in consequence of which no sparks will be produced when the motor is cranked. 

With the switch thrown to position (B), the magneto will continue grounded, but the 

battery circuit will be completed, and in consequence, the breaking of the circuit by the 

timer-distributor will result in the production of a spark that ^Hll be transmitted to the 
proper cylinder by the distributor. 

The same condition will exist with the switch thrown to portion (MB), except that then 
the magneto ground circuit will be broken and that magneto sparks wUl be produced in ad- 
dition to the battery sparks. 

With the switch thrown to position (M), the magneto will operate in the normal man- 
ner, and the battery circuit will be broken. 

KO. 188— Magneto Wiring Diagram of a High Tenaton 
''Double" Ignition System. 
iM^— 9!b# JTStSB tg. 8, Is kaowB m tho **Bof€h Bstlwy. Ooil SB 
f a i ywiwm €mplmtk9d sot jMgit tb%, 
M# foot Mote bottom of p^^ 281, 

" ••Dual 
■ad la 



Examplea of Magneto IgnltloiL 

Ttie magneto waa ertenslvely used In tlie 

put on pleasure or ptisseiigcr cars, hot tbe 

bigh teaflion "coil and battery'* ignition 

' has taken its place for reasona stated on 

I>age 265. 

Ttio magneto is now extensively used on 

tincks and tractors for reaaona stated on 

■ pAge 255. The truck and tractor eaginea 

[ftro seldom equipped with electric starting 

I motors, but are equipped with ' * magneto 

I ignition" and "impulse atarters." In fact^ 

during the war very near every tmck in 

Government use was tEus equipped^ which 

eHminated the battery and complication. 

Dual Ignition. 
Dual system of Ignition: Where a car baa 
two ignition systems for instance, a "coil 
^ And battery*' and independent "magneto," 
^ hut both systems using one eet of spark 
plugs — this system is called a ' ' dual * * igni- 
tion system. 

Dual ignition Is quite common where 
magnetos are used, that is, before the ad- 
T«nt of the "Impulse starter.'* The idea 
being to have an auxiliary battery and 
coil system to start on, and the magneto 
to run on. 
There are two general principles of dual 
I Kyvtems, which were formerly used to a 
great extent; the "low tension magneto" 
and a separate "high tension coll" and 
battery — per pages 262 and 2 §3. The coil 
and battery were used for starting engine; 
after starting, the magneto supplied the 
current to the coiL 

The other method was by the uae of a 
"high tension magn«to" and a aeparate 
and distinct "high tension coll" and bat- 
tery ignition system. The engine was 
started on the battery and coil system then 
switched over to the high tension magneto 
which was independent of the colL 
An example of a dual system using a high 
I tanalon magneto and soparate high tension 
coll and battery is shown in fig. 2, page 276. 
High Tension Magneto Alone. 
In fig. 1, page 276, note the high tension 
f magneto supplies current to the four apark 
plugs on a four cylinder engine. 

The armature ia double wound; therefore 
a separate coil is not necessary. The dis- 
tributor on the magneto distributca the 
high tension current to the apark plugs. 

The disadvantage of this system is in 
•tartingy the armature on magneto must 
be revolved fast enough to generate cur- 
rent before the spark will occur at the 
, plugs. Therefore it is necessary to "spin" 
I the crank. This is not a very satisfactory 
, fyitem unless an "impulse starter" (page 
B32} ia used as explained on page 255 and 
\ Above. 

When equipped with an impulse starter 
it is a desirable system for trucks, tractors 
and stationary engines. 

Double Ignition. 
Double system of ignition: Where two 
riets of spark ptugs are used with two inde- 
i|>e«dent ignition systems — this is called a 
^'double" system. 
*S«« ftl«o. |>tffl 927 «od Ifittrt Ko. 1. 

An eieample of a "double" ignition ays- 
tern using a battery, high tension coil, timer 
and distributor for one system and a high 
lenaion magneto for the other with two 
spark plugs in each cylinder, Is shown on 
page 276, fig. 3. 

Another form of Double System. 

Referring to page 278, note the sepurate 
and independent high tension magneto. The 
coil and battery aystem is similar to the 
master vibrator system, explained ou page 
230. See page 27B for further explanation. 

*T1i« Plorce- Arrow Angina, from the time lti« 
■yitfim on page 278 wAf diioontinuod. up to 
Jiilj, 1919: uied a "double*' ■yatem conaUting: 
of a bigh tenaion magneto with an mdependent 
set of apark plogi and a aeparate coil aiif! bat- 
tery igoitioo with another aet of tpark plnga. or 
two flpark plugs per cylinder per page 276. 
EUber aystem could be tiaed Independently or to- 
getbor. When uaod tofother. tbia insured a Tory 
hot aparic \n. th« cyliDder with reaalt that more 
pov«r iind leai gaaoUiio ii eonsfimed, »a eifilained 

The lat« 1010 Pierce- Arrow nsoi a Deloo bAt- 
tery tad eoU tgulUon ajiiemt uaing a "double" 
timer and dUtributor and two apark ploga Co each 
cylinder. A fe&erator ia uaed to charge the 
battery. The magneto hai been eltnainate^d. 

Two-Spark Igoltioii System. 
The ''two-spark*' syatem used in connec- 
tion with a bigh tension magneto is ex- 
plaijied below on page a 283, 926. Here we 
have two distributors on the one magneto 
and two apark plugs are provided for each 
cylinder. The principle ta aimilar to the 
''doable'' system except the one magneto ia 

-ifmnm tftUM 

C*fiVf tt<D ua^^^ci BBifthi*'- 

Remy two apark magneto. 

The idTuitsge of h«Tliig two tpvli pltiga fire 
at one time In eaeli cylindarp la to increaae powtr 
and vpead, azpLaiiied a-a followa: By referring 
to page 307 we learn thai thirc ia a difTereoce 
between the time when the apark occara and the 
actual time of combuttion. Therefore with a 
weak apark, the time of apark ia made to ooeur 
earlier, that U, "advanced" before piston reacboi 
top of the compreiAioa atroke, in order that it 
will ha¥e time to ignite the gas, combust end 
expend before piatoa geta to far down on power 
etroke. With a "double" ayatem or "twotpark" 
•yatem, or e good hot apark^ this ad^rAtiee of igni- 
tion ia leaa, aa the combnatlon ia almoat inaten- 
taneont. cona^qntntly, with leaa »dTancement of 
apark, there ia leaa liability of firing beck on the 
piaton before it reach ea the top of compreaBioa 
atroke and furth^-inQre there ia « aaving of gaao- 
line, becauae with a good hot apark all of the 
gaaoline ia ignited and aaed for power insieed of 
part of it paasing o^t the axhauat not folly 
ignited. In other worda a weak apark prodoeea 
■low eotnbuailoa and a hot apark qnick combaa- 

TwO'Point Ignition System. 

The **4wo-poiiit" B3rstem. where two 
sjKurka occur at the samt time but In dif* 
ferent cylinders, la shown on page 284. 

On a four cylinder engine, the spark 
would occur at two apark pluga at once, but 
inasmuch as on© of the pistons would bo on 
exhaust stroke, this would make no dif- 



Bosch Vibratliig Duplex System. 

This system is described in chart 187. Its 
purpose is to assist in starting. Do not 
cenfose this system with an electric system 
of starting by movement of crank shaft. The 
principle of this system is to supply a sep- 
arate battery and vibrating coil to start 
engine on, doing away with a dual system. 
See chart 137 for further description. 

To Time the Magneto. 
Which is a Bosch DU4 or DU6 as an ex- 
ample. First place piston of No. 1 cylin- 
der on top of compression stroke, and with 
magneto interrupter housing retarded set 
contact points just starting to break. The 

driving means can then be coupled up. 

The timer distributor, fig. S ehart 133, 
should then be revolved (in direction of ro- 
tation) until timing interrupter is in the act 
of breaking. 

To Time the Eisemann "O" Types. 
With these systems it is merely necessary 
to bring No. 1 piston to top dead center, 
rotate the magneto until the setting mark 
on the distributor is opposite the pointed 
screw at the top and couple up the drive. 
Use marks "B" or "L" for right or left 
hand rotation, respectively, as needed — ro- 
tation being judged from driving end. (see 
page 285.) 

Instructions to the Beader. 

If the reader will master the purpose and 
principle of the following, it wlU then bo 
easy to analyse any system of Ignition he 
may come across. For instance, learn the 
difference between; low tension coils, high 
tension coils; low tension magnetos, high 
tension magnetos. 

Other details to classify would be; the 
difference between the commutator, timer 
and interrupter, and sources of electric sup- 
ply, as direct current chemical generators; 
(dry cells and storage batteries). Direct 
current, mechanical generators; (dynamos). 
Alternating current, mechanical generators; 

Methods for distributing the secondai^ 
current to the spark plugs; by a distri- 
butor as used on a magneto, or by a commu- 
tator in connection with a vibrator coil. In 
other worls, very nearly all of the systems 
compose one or more of the parts of the 
four principles of ignition. 

Difference in Makes of Biagnetos. 
An inipection of the illustrations of the 
different leading makes of magnetos shown 
in chart 141 will give the reader an idea 
of the variance in construction. In this 
ehart we Ulustrate magnetos of the low ten- 
tion type and magnetos of high tension 

As previously explained, the low tension 
type of magneto employs an armature wound 
with only one winding of wire, which is 
called the piimary winding. We learned in 
a previous instruction that when a magneto 
employs a single primary wound armature, 
then a transformer (high tension coil) sep- 
arate and distinct from the magneto, is nec- 
essary in order to step up or transform the 
low tension voltage, (pressure) up to a high 

By referring to chart 141, we find that the 
Bcmy and Sp&tdorf ( in the models shown) 
have piimary wound armatures and need sep- 
arate eoils or transformers. But going a lit- 
tle further into detail, we find that the SpUt- 
dorfy Elsemann, Bosch, Mea and the pivot- 
ing magnetos all have armatures which 
rsiTtflrs wtlh the winding wound on the re- 
volving part. 

In the Bemy and K. V. we find that the 
winding does not revolve, but is stationary. 

"Armature" and "Inductor" Type; 

"Primary" and "Ck>mponnd" 

Wound Magnetos. 

The revolving type of armature, with the 
wire wound thereon, is called the "arma- 
ture" type, and the type where the wire is 
stationary is called the "inductor" type. 

If there is only one winding it is called 
a "primary" wound armature. If there 
are two windings, then it is called the 
"compound" type, (see chart 132.) 

The primary wound armatures are low 
tension, and require separate coils. 

The compound wound armatures are high 
temdon, and do not require separate coils 
— only as a matter of convenience for easy 
starting or dual systems of ignition. 

We wlU now go back to the "armature" 
and the "inductor" type. Up to the pres- 
ent we've shown only the Bemy and K. W. 
with an inductor type of armature, with a 
single, primary winding. 

By referring to the K. W. magneto, in 
chart 141, we find that the winding on this 
type is also stationary, but instead of be- 
ing a single primary winding, as on the 
Bemy, it is a double or compound wound 
armature like the Bosch, Eisemann and Mea 
— ^but differs from the last mentioned in that 
the winding does not refvolve. 

In the Bosch, Mea, and Eisemann the ar- 
mature is compound wound and of the 
"armature" or revolving tjrpe. The prin- 
ciples of the magnetos are about the same, 
with some few minor differences in con- 

"Pivoting" or "Rocking" Type 
The Mea magneto differs in that the mag- 
nets can be turned ftom side to side (called 
pivoting type); they are bell-shaped, and 
placed horizontally; therefore, ui^ke the 
customary horse shoe type, mounted verti- 
cally. In this construction the magnets 
and breaker are moved simultaneously in- 
stead of the advance and retard of contact 
breaker alone. 

— eoatltLu«d «u ^%i,« ^V\ 



The Bosch Dual IgniUon System. 

TlM parts of tbii tTStem ar« shown In flg. 2. 
Thii systBrn proridM s coil and bsttorj system and 
a high-tension magneto system, both independent. 
One set of sparlc pings and one distributor on the 
magneto is used for both systems. 


5idf V 

md Swii 

-rM-gGr^ Win 
-tflst Tiificr 
^— , S 

Mag. Can 


Fig. 2. Wiring diagram of the Bosch DUi dual 
ignition system. The DU4 type magneto is fitted 
with two interrupters as shown in flg> 6a. instead 
of one interrupter as shown in fig. 2, page 270. 

Fig. 6a. Tha magneto is the regular DUi high- 
tension magneto fitted with a separate and indepen- 
dent timer or interrupter 
for tho coil and battery 
system. This cpntaet- 
breaker has no electrical 
connection with the mag- 
neto. The second altera- 
tion from that of the reg- 
ular single Dn4 high-ten- 
sion magneto, consists of 
, the remoral of the connec- 
tion (see Q, fig. 2. page 
268), which on the ordi- 
nary magneto connects the high-tension collector-ring 
to the distributor: now that the distributor is to do 
duty for two ignition systems, it is necessary that 
the current be carried to it through the switch, yia 
wire 4 when the battery and coil system is switch- 
ed on (see fig. 7, also, fig. 2), or via wire 3 when 
magneto is switched on (see fig. 6). 

Tr, Hi, 

4. 13 

COIL « swrrcH 

Fig. 8. The coil and switch is shown above. 
The coil is a double wound high-tension coil. 
The switch and coil are mounted on the dash. The 
switch controls both ignition systemi. Note when 
switch (11) is turned the coil with its core (20) 
and winding, and end of coil (17) turn also. 
Switch plate (16) is stationary. 

Parts of tho switch and ooil aro as follows: 11, 
switch handle (also called, kick-switch) ; 12, mov- 
able switch cover; IS, coil ease; 14, starting press 
button; 16, fixed or stationary switch plate (see 
also, fiigs. 16 and 16a) ; 17, movable switch plate 
en rear end of coil (see also, fig. 17a) ; 20, iron 
oere of eoil over which primary and secondary 
are wound; 21. plate carrying the starting arrange- 
ment and condenser; O, condenser. Note primary 
winding eonneets to it at 8; 23, eontact spring; 
24, trembler blade also called vibrator blade; 26, 
26, auxiliary contact-breaker; 27, trembler or vi- 
brator spring; 28, screw holding switch plate to 
coil; 29, locking key; SO, dash board or cowl. 

Fig. 8 A. Front view of switch. M, magnet side; 
B, battery side. 

Fig. 8B. Side Tiew of switch and eoil oMa. 

Fig. 17. Front view of coll to which tha switch 
is attached; V — is the trembler or vibrator blade 
(26, fig. 8) ; 14, the press button eontaet. 

Fig. 17A. Bear morabla swlteh-plata with bus- 
bars and connections (Z) on end of eolL 

Fig. 16A. Inner sida of stationary swltch-plata 
showing connections 1, 2 8, 4, 6 and 6 which make 
contoct with connections (Z. tig. 17A) when switch 
is turned to B or M side. 

Fig. 16. Boar and view of swltch-plata (16. fig. 
8) showing terminals to which wires are connected 
as shown m fig. 2. 

Starting Engine. 

The engine is usnaUy started by switch being 
placed on the B or battery slda. The interrupter 
(1) on magneto being used for the primary winding 
on coil and the distributor on magneto being used 
to distribute the high-tension current to the spark 
plugs. Otherwise the magneto has no connection 
with the battery and coU ignition system when 
switch is on the B side. 

In order to start angina with tha starting 
handle (or electric starter, if one is provided) the 
press-button (14, fig. 2 and 8) is pressed down 
and then turned at right angles, a process which 
locks it in position for the trembler si>ark. 

The engine can also be startad on tha switch 
or "ignition," as it is often termed. The switch 
is turned to B side and then the brass press-button 
(14) is pressed down. Often times this will start 
engine, if cylinder has a charge of gas in it. If 
not, then it will be necessary to crank engine 
after locking press-button as explained above. 

To explain this ignition starting feature, see 
fig. 9. The 6 volt storage battery (or 10 dry cells) 
is supposed to be switched on (B, side). 

Fig. 9. 

—continued on next page. 

OHABT NO. 134— Bosdi Dual Ignition System— eontinaed in charts 185 and 186. 

Wiring connections from distributor to spark plugs are not in regular firing order. Ifaln pnrpoaa of diagram is 
to shoir Switch CircuitB. 



— continued from p^ge 280. 

SUrtinf from th9 left liand itorsge bftttery ter- 
minal (to make it eaaier to understand), the cur- 
rent paitei through the primary winding and ar- 
riree at the end of the trembler blade and tha 
blade above, called the auxiliary contact breaker. 
The current cannot travel beyond the trembler blade 
because, as will be seen, the platinum points are 
separated. Neither can it complete circuit along 
the auxiliary contact breaktfr blade because the 
main contact breaker (left hand lower corner) 
also stands open, being the position in which the 
contact breaker always comes to rest when the en- 
gine stops, save for the few occasions when the en- 
gine stops with the piston about dead center. 

To start the engine therefore, we have only to 
press the button so that the upper platinum point 
comes into contact with the lower one, and immedi- 
ately the circuit will be completed, the trembler 
start buzzing and a shower of sparks sent through 
the plug of the cylinder which is next to fire. Now 
the work of the trembler blade is done, the engine 
has started and the main contact breaker is set 
in motion. The current troubles no longer about 
the trembler blade, but follows the upper path 
along the auxiliary eontaet breaker and throntrh the 
main contact breaker, the making and breaking of 
which does the work of the trembler and creates 
the high tension current. The engine may be 
kept running in this manner at the pleasure of 
the driver. 

The auxiliary contact breaker, fig. 9: Now let 
us take the exceptional case of the engine stopping 
wtth tha piftons about dead center and the main 
contact-breaker points (B P) closed. The current 
this time finds an easy circuit through the closed 
points, the iron core becomes magnetised, the 
trembler blade is held down on the core, and press- 
ing the button as before has no effect. No spark 
is made because there is no break in the circuit. 
But if the reader will examine the diagram closely. 
he will observe that the act of pressing the button 
presses the auxiliary contact-breaker blade away 
from its upper platinum point and on to its lower 
one the momentary break thus caused in the circuit 
being sufflcient, under the circumstances we are sup- 
posing, to create the necessary high tension current 
for the spark in the cylinder and so start the 

When the engine stops in the more usual way 
with tha itorMe battery contact-breaker open, the 
npening and closing again of the auxiliarv contact 
blade has no efTect. The diagram, fig. 8, shows 
the coil as it actually exists. 

Battery axid Ooil Position. 

Fig. 3. Illustration is supposed to represent 
rear of coil and switch. Points 8 and 4 are not 
ronnected, consequently magneto secondary circuit 
is open. Note magneto primary wire Is grounded 
at 2. therefore it is out of service. 

G HG. 3 BATTERY rpg '- 


••— TIMER ' 

Coil prtsnary circuit: When switch is on B side 
the current in battery leaves it at the positive ( + ) 
side and travels through ground wire (O) to battery 
and coil timer or interrupter, which is operated 
by a cam on the magneto. The course is then to 
post 1 through mechanism in direction of arrows, 
to point 8. I 

It flows then through primary winding (PW) 
of coil, and as the arrows show, through point 6 
back to battery, thus completing the primary cir- 

Coil secondary drcnit: In passing through prim- 
ary winding, a hifh-tension current is set up in 
the secondary winding (SW), when breaker-points 

This high-tension current flows to distributor 
wire at 4. Thence to magneto distributor (D). 
Here it is passed to the different spark plugs in 
order. It goes through the spark plug center 
terminal across gap to shell of plug to cylinder, 
thence to ground back to other end of secondary 
winding (note lower end of secondary is grounded 
to bus-bar Z which is grounded with 6). The coil 
condenser Is shown at C. 



f f 


I I - ^ ' I Switch 

Fig. 7. Outside wiring of the battery and coil 
system when switch ii on B side. (Note points 8 
and 4 are not connected, thus opening magneto 
circuit). Primary current leaves battery and 
travels to ground (O). As 6 is grounded, current 
goes to 6, thence to 2 and along 2 to the magneto. 
Then to 1 on magneto along wire as indicated by 
arrows to the point 1 on switch pate (16). Here 
it travels through primary winding (PW) of coil 
then to 5 and back to battery, thus completing the 
primary circuit. The secondary circuit is frolh 
4 to distributor, thence to spark plugs. 

Note: when switch is turned, the rear end of 
coil (fig. 17A), with the bus-bars (Z) moves and 
connects with inner side of switch plate (16A). 
Therefore, when switch is thrown on B side the 
point 1 on switch plate (16) lines up with point 
1 (one of the bus-bars Z) on rear end of coil (fig. 
17A), likewise 2 and 5 line up with bus-bars on 
the end of coil. 

Magneto Position. 

Fig. 6. Note switch is now on (M) magneto 
side and there is but one closed circuit; it was made 
by connecting 8 and 4 on switch plate (16) with 
bus-bar (Z) on rear of coil. Note all other points 
of contact are open. Including the magneto short 
circuiting or grounding wire connected with 2. 



Magneto primary dreuit is then from primary 
winding (PW) of magneto armature, to magneto 
interrupter (M), thence to ground. Other end 
of primary winding (PW) Is grounded, thus com- 
pleting primary circuit. 

Magneto secondary drentt. One end of second- 
ary winding (SW) goes to 8 and 4 which are now 
connected with bus-bar Z. From 4 it flows to distri- 
butor (D), thence to and through spark plugs. 
Here the current is grounded. The other end of 
— continued on next page. 

OKABT NO. 135 — ^Bosch Dual Ignition System — continued. 

In praetiee, eonnections from distributor to spark plugs are not as shown; if so. it would fire 1. 2. 8, 4, wheta- 
as ft should conneet to fire 1. 2. 4, 8 or 1. 3 4, 2. Main purpose of diagrams is to aVio^ ^V\\.0[i ^\tc>x\\.%. 


: fr-A ^mf* Zil. 

i— r w*i.f-^y f SIS' I U crounded also 

irire 4. then to dsitributor where it is then distri- 
buted to tpark pings. 


Fig. 4. Off poittlon of swltcli. Note in this posi- 
a there is no complete circuit, as points 1. 5 

and 4 of switch>plate do not coincide with points 
1. 5 and 4 of coil switch-plate, note primary dr- 
eott of magneto is sbort-circuited, or grounded at 
2 on Bwiten-plate, thus it is out of serrice. Mag- 
neto locondary drcnlt is open from 8 to 4. 

Sxaefl ? 

or Dual Double Ignition System. 

(if. ab) 

ia aa followi: 

tbe primary 

lirau^ rho hreaker- 

if'h ex the points a 

KK 15 


_ n the secondary 

'zrr-ia m -atg "M magneto at 8 and 

:.:r rtnnr f at dbe M& aa indieatod by 

"^ts -t'jxn. jto-Z S :o point 4 and 

::te dmcs-'.nrxr ws«l aSoag thia wire 

• cc an -ttmpxast. T\« diatrflmtor arm 

-fit :m mrraL.- w^A xa tvm la aont to 

'^-. ?>ruj» w a.i>:aasid by the arrows. 

pr: sr am;: ^ "A* gr9XBd after learing 

*in:s- uit Tttf 1^--:<:^:C3 or secondary 

>f*nic ^tivti'fi i: ise «::i. the secondary 

Whan tho two-point awitch (flg. ab) li thrown so 
that both Mtf of plnga aro to oomo into play, both 
distributors of tho magnoto beeomo oporatlvo. The 
path of the primary and secondary current to the 
magneto in this ease is the same as before, but 
when delirered to the magneto the enrrent ia passed 
to two distributors instead of one. In this way two 
distinct electrical currenta are distributed to two 
different sots of spark plugs. 

Tho coll and battory ignition can bo osod indo- 
pandant of tho magneto by switching to the B side 
of awiteh (flg. 3a) and one or both sets of plugs 
connected with two-point switch (fig. 2b V See 
also, page 288. (Motor Age). 

FIG. 3 


' 2UX x*JDsr lira, j^-posir JumfOf, 

/2 .' i\ 

7/ffs son/ s^TS if.vr 

Doftl Ignition System — eontin»ed. To time this magneto, see pa^re 311. 

Synk or Dml-DoxAAiB Ignltian r 


BoaCh Two4pMk Magneto. 


Th« pnrpoM of tbe Boseli two-fp«rk magneto 
!)• Is to vrodvoo Spiitton a* two plug polnta In 

ejllndor, in order to rodneo the tlmo intenrai 

botwoon inltion and eomploto eombnatlon; and, 
whoro it b poaaible to looato two apark vlnga in 
•aeh eylinder at ahown on pago 286 and 282. The 
raanlt ia to rednce the igmtion adranco neeeaaarx, 
and thna to seenre an increaae in the effleleney and 
ontpnt of the enffino. See alao, page 277. 

HcAtiesT n SecoHo Ser 





FIG. 1 

Fig. 1. Boaeh two-apark mag- 
nofeo ignition syatem. 

rig. 2. Switch: 0, off; 1, one 
aet of phiga operating; 2, both 
ft seta operating. 

Fig. 2. SV^ITCH 

The typea ZI14 and ZB6 Botch magnetoa are 
produced with the two-apark. independent -or dual 
form. The noticeable difference in the two-apark 
magneto from the aing le-apark magneto ia in the 
doable diatribntor D D and arrangement of the 
•afety apark-gap under the arch of the magneta. 

In tlia Binglo-spark magneto, the beginning of the 
armature aecondary eirenit ia grounded on the arma- 
ture core through the armature primary eireuit, 
wiMraaa In the two-apark magnato, the two 
nda of the armature teeopdary circuit, are 
connected to two aeetional metol segmenU dia- 
motrieallT oppotite on a tingle alipring. Two 
iltpring bmanaa are prorldad, which are horisontal- 
ly mounted in bruah holdert on oppotite tidea of 
tbe thaft and plate. During the portiont of the 
armature rotation when high tension current is be< 
ing deliTored, each of the two slipring segmenta 
will be in contact with one of the brushes. One 
Vmsh ia connected to the Inner diatrflmtor by meana 
of a conducting bar similar to that uaed on aingle- 
■park magnetos, the second slipring brush is con- 
nected to the outer diatribntor by meana of a short 

length of cable paaaing aronnd the magneta. The 
rotating diatribntor piece .ia of double length and 
carriea two bruahea inaulated from each other. 

The four and alz-oyllndar tjpaa are fitted with 
eight and twelre distributor outleta respeotiToly, 
each pair of outlets being eonnected to the apark 
pluga of the proper eylinder by the usual cables. 

Path of the current is similiar to the Berling 
two-spark magneto, page 926 and page ^282, fig. 2. 

AdTanee and retard: The use of two-spark igni- 
tion permits the ignition lead to be cut down any- 
where from 80 to 60 percent. It will be underatood 
that if the timing ia eorreet for two-spark ignition, 
and one of the series of spark nluga Is cut out of 
action, the remaining series wifl operate conaider- 
ably in retard of what it would if the engine were 
timed for single-spark ignition, therefore, if the 
two-spark ignition nroridea the full adrance, the 
effect of retarding the spark is obtainel by outting 
out one series of plugs. 

The awiteh proTldad for the two-apark Indepen- 
dent magnetos, ia ao arranged that Ignition may be 
aeenred either with both itta of apark plugs, or 
with but one aet. The purpose of this ia to give the 
effect of retardfaig the spark, without altering the 
relation between the interrupter opening and the 
armature, aa ia done under normal conditions. The 
connectiona should be so made, that the system of 
plugs that ia operatiTe when the awiteh ia thrown 
to the single position, is located near the inlet 

In starting — throw switch lever to ' 'single ping' ' 
position — this gives the effect of a retarded spark. 

For ordinary nmning, operation should be on 
both seriea of pluga; for alow work through traffle, 
or when the engine ia running idle, use the aingle 
plugs, or only one set. 

Timing: Time aa explained for timing a single- 
spark magneto, at top of page 810 (interrupter re- 
tarded and piston on top of compression stroke). 
It will be found however that this timing will like- 
ly five two great a apark advance when Interrupter 
is fully advanced, as the two-spark magneto should 
have from % to % the advance aa that of a aingle- 
spark magneto. Therefore retime, so that the in- 
terrupter pointa will open slightly later. A good 
method to follow ia as per below. 

To replace a single-spark magnato witt a two- 
snark Instmment, the maximum advance for the 
single-spark magneto is to be marked — preferably 
on the flywheel--and the two-apark magneto timed 
in advanced position, so that the interzupter opana 
the eireuit, at a point midway between the mark on 
the flywheel indicating the single-spark advance, 
and that indicating top dead center retarded. A 
more exact timing may then be secured by experi- 


^ FIG. 2 


Arrangement when employing 
battery of ■ a grounded lighting 
or starting system, or separate 
battery for ignition. 


The Boacli Vilnratiiig Duplex System. 

The Bosch vibrating duplex ajstem is designed 
to permit easy starting on cara that are cranked bT 
a starting motor at such a low speed that the igni- 
tion current from the ordinary magneto ia insuflieient 
to give certain ignition. 

How it operates: The arrangement ia auch that, 
while the magneto circuit is abaolutely independent 
and complete in itaelf, the battery circuit includea 
both tbe coil apd the magneto. With the switSh 
in the battery position, the battery and coil are 
in series with the primary winding of the mag- 
neto armature, and the current from the battery 
supplements that generated by tbe magneto. Thna 
there is induced in the secondary winding of the 
magneto armature, a very powerful sparking current* 
which, on account of the vibrator action of tbe coil, 
appears not aa a single spark, but aa a series of in- 
tense sparka that will act with certainty on any 
exploaive mixture. The sparking current so pro- 
duced ia distributed in the usual way by the mag- 
neto distributor. After engine ia started, the swUoli 
is turned to M side and coil and battery are diacon- 

GSABT HO. 187— The Bosdh "Two-Spark" Magneto Ignition System. Bosch Vibrating Duplex 

The "Twespaili" system regular eouipoient on Btnta nnd Mercer. Alto been utad on %om« 'VIKTS, lAt^a^m.^^^^ 
mi XaratoB eara. Bee alao, page 928 for Berling two-spark magneto. 



Fig. 1 — Four high tension ignition systems connected to one four cylinder engine. Only 
two systems are usually placed on an engine, and then, only one system is used at the time. 
The idea is merely to show how the various systems can be combined into ''Dual" or 
''Double" Ignition Systems, as explained on page 277. 

The Tlbrstlnc ooil !■ leldom used. The low-tension magneto is seldom used. A modem "dnal" end 
"double" system is as per pages 276. 280. 281 and 2t}2. A modern "battery and coll" system is as per pages 
842, 346. 878. 262. 250. 

Fig. 2— Wiring diagram of a donble system of Ignition diowing the switch arrangement; ; 
a high-tension magneto with a separate set of spark pings. A multiple nnit tjrne of vibrator | 
coil with commutator (marked "timer'') and battery and a separate set of spark phigs. 

(Trace circuits with pendL) 

GHABT NO. 140— Four Hlgk Tension Ignitioii Systems Monn to d tm One Four Oyllnder Bnglno to 
. Sxplmin the ComhinMon of Systems. 
Bmm foot aoto bottom of pmg9 281 which ret9r» to flg. 1. 



~-<aotlno«d from page 270. 

This style of m&gneto, owing to the fact 
that it is rocked from side to Bide> ^ves 
an unlimited range of adv&nce, and thus 
sdds wonderfull^r to the Hexibilit^r of the 
CAT on which it ia mounted. TMe gre^t 
rajige of advance makes this InBtrument 
especially suitable for two-cycle engines, 
which require a much greater degree of ad- 
vance and retard than the four-cycle tyx>e. 
8ee page 2S9 for deacription. 

Magneto; Automatic Advance. 
The Elsemaim automatic advance of 
spark; with all magnetos treated up to the 
present time^ the advance and retarding of 
the time of spark is accampliahed by hand, 
called *^ manual" advance, by means of 
spark lever on the steering wheel. With 
the Bisemann automatic advance, the same 
thing ia accomplished by a governor ar 
rangement automatically. This type of 
magneto is extensively used on commerciml 
cars, (see chart 14 3 for description.) 

•'Combining** the High Tension Magneto and Coll and Battery System Into 
**I>ual" and *' Double" Systems, 

W# hare now explained the different 
leading low and high tenaion Ignition sys- 
tems for firing the charge of gas in the 
gasoline engine. In order to more clearly 
explain the four leading systems of high 
tension ignition, we will now place the four 
ignition systems Chigb tension) on one four- 
cylinder engine. (F