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Awiomslire Brngime^riftf, Konnerlv Slanaicins Mitor. M'^t'.r Lif*. I>lttnr. 1^* '•^mmt^mnt I'ekirU, 
•Cc.;A«lhor off "What K««>r> AaU>0i<jhilj><>wneri<hotild Kmm." M**inl>er. Sn« '.f'ty of Aoto- 
■Mibile Eaciiur^n. Member. American Society of Mechanical Elncineer^ 







'HE modern automobile is mechanically a fine piece of 
engineering and it represenis in its development the 
product of the best technical brains of the country. The 
engine has changed from the halting, wheezy, unreliable con- 
traption of fifteen years ago into a perfectly dependable, well- 
behaved, and sweet -running mechanism which carries its owner 
at high or low speed, in the heat of summer or the cold of 
winter, over all sorts of road with exceedingly rare periods 
of distress or failure. The same evolution has taken place 
with each part of the automobile until practically all the 
\ changes in present-day models are simply refinements of the 

fs existing mechanisms. No expenditure of money or skill has 
^ been spared to make the automobile as near perfect as pos- 
:^ Bible. As a result, it stands today one of our best examples of 
well-rounded development, a device which has had more to 
f>( do with our progress in production manufacturing in the last 
> ten years than any other single machine which could be men- 
N^ tioned. Therefore, it behooves those who are interested In 
* this development to study the construction and design factors 
^ with great attention. Lessons are to be learned from the 
evolution of this device, from the failure of that design, and 
i the study of "near perfection" is always profitable. 

([ This volume has been designed not only for the man who 
is interested in things mechanical, but more especially for 
the designer, for the mechanic who Is engaged in automobile 
construction and repair work, and for owners and chauffeurs 
who wish to be their own repairmen. The discussion of the 
construction of valves, clutch, transmission, etc., is confined 
mainly to the standard types without much attempt to trace 
the historic background. As to the repair sections, there are 
many ways of effecting repairs on an automobile, but the 
advice here given is based on careful observation and broad 
experience. The sujggestions range from the engine to the 
differential, from the steering gear to the tires. The excep- 
tionally full section on carburetors and carburetor adjustments 
and the section on tire vulcanizing, with the description of 
proper tire repair methods, will be found especially helpful. 
No attempt has been made to cover "Ignition, Starting, and 
Lighting Systems,*' as this has received an exhaustive treat- 
ment under that title issued by the same publishers. 



Engine group 11 

General engine features 15 

rylinder forms and const nut ion 22 

Pistons and accessories 48 

Ponnecl Ing: rods 61 

Crankshafts 72 

rrankcases 84 

Carburetors and carburetion 99 

Function of carburetor 99 

Effect of heavier fuels 99 

Classification 101 

Throttle valves 103 

Carburetor operation 112 

Kerosene and heavy fuel carburetors 180 

Carburetor troubles and remedies 194 

Inlet manifold design and construction 20r» 

Changes in design 20r> 

Heating the charge 209 

Inlet manifold troubles 210 

Fuel supply 211 

Tank placing 211 

Fuel feeding 211 

Piping and connections 211; 

Reserve tank 217 

Fuel system troubles and repairs 218 

Valves and their mechanism 227 

Valve features 227 

Poppet-valve gears 232 

Repairing valve parts ^ 252 


Valvu and their mechanUm (continued) 

Sliding sleeve valves 271 

Rotating valvee 278 

BxtaauBt syatem 279 

Cooling ■yatama 28G 

Water cooling 28G 

Air cooling 300 

Troubles and adjiistnieniB 302 

Lubrication ayatem 305 

Motor lubrication 30r. 

General lubrlcallon 321 

Oils and greaapK 322 

Lubrication troubles and remedies 32."i 

Bearings 330 

Flywheel aub-group 337 

ChararleristiCH of flywheel 337 

Melhods of fasleiiinK flywheel 33fl 

Flywheel markings 3311 



Steering group 445 

Steering gears 445 

Steering wheels 470 

Steering rods 474 

Front-wheel drive 480 

F^our-wheel drive 482 

Electric drive 489 

Front axles 491 

Chassis group 508 

VFranies 509 

Springs 530 

Shock absorbers 549 

Final-drive group 569 

Rear axle 581 

Brakes 604 

Wheels 622 

Tires 645 

Rims 654 


ilifiliisliisi gf 




Of all the applications of the internal-combustion motor, it is 
safe to say that none is more important than that applied to the 
propulsion of the modern motor vehicle — the automobile — which 
nowadays throngs the roads and streets of nearly everj'^ country in 
the world, and serves a myriad of utilities as they never have been 
and never could be served by animal transportation. 

Standardized, inexpensive to buy, and inexpensive to operate, 
almost unfailingly reliable, and proved capable of use in the hands 
of even the most unmechanical of operators, the automobile is at 
last coming fully into its own. Its design has become recognized as a 
branch of engineering by itself, its manufacture constitutes one of 
the greatest of the mechanical industries, and its use is a common 

Naturally, in so tremendous a development, there is sustained 
by the general public every possible sort of relationship with the 
automobile, from that of the merely casual observer and occasional 
user, to the more interested owner; and thence on, in e.ver closer 
touch with the full significances of this field of engineering, to the 
high-skilled and well-paid drivers of cars, the experts who repair 
them, the shopmen who build them, and the engineers and draftsmen 
who design them. 

All along this line there is an increasing need for knowledge — a 
demand for definite, specific, usable information concerning the 
science upon which the motor vehicle is based, and the practice upon 
which its construction and performance are founded. 

In no other important field of engineering is there such a lack of 
correct and authoritative literature as in the automobile field. 

This undoubtedlv is due to two conditions that have been 
involved in the rapid growth of the automobile from a mere experi- 
ment to an achieved and commercial fact. The first condition is 


the circumstance that the men who have deeply studied the auto- 
mobile from an engineering standpoint, and who are best informed 
about it, have not had the time to place upon paper the facts with 
which they are acquainted. The second condition — resulting from 
the rapid development of automobile design and engineering practice 
has left no time for the establishment of a formulated science, upoD 
which textbooks of a genuine and permanent authority may be based. 

What follows will be an advanced and comprehensive treatment 
of the very latest devices applied in automobile engineering. AU 
are carefully described, their essentials fully analyzed, and their 
important details fully illustrated. 

Historical material of any kind is useless in a work of this sort, 
which is intended primarily for the man in the shop, who does the 
actual work of coinpleting the car in the first place, and the man in 
the garage who keeps it in running order thereafter. It will suffice to 
say that while most of the worthy efforts and early progress in the 
development of the explosion motor and the automobile were made 
abroad, American designers and American workmen have since 
shown the way in this field to the whole world, so that today we import 
a negligible number of motors and cars, while we export to every other 
country of the world. 


the rear wheels, and thus propels the car. Of necessity, this indudes 
the rear axle, while the front axle is usually grouped with the rear; 

(5) the steering de\4ce, for controlling the direction of motion; and 

(6) the frame, upon which all these and their various accessories 
are hung, with the springs for susi>ending the frame upon the axles 
of the car. There is, of course, a seventh group, the body, but that 
need not be discussed here, since reference is now made only to the 
medianical parts. 

Enguie Qroup. In the large diagram of a modem motor car. 
Fig. if the sectional side \new is shown above, and the plan \new 
below. In this, note that the engine is placed at the front of the 
outfit. This is now the position nearly all modem motor car manu- 
facturers use. A few cars have the motor located on the rear axle 
to save the parts necessary for connecting the two, while formerly 
the middle position was a favorite one. The purpose of the engine 
is to generate the power. This is done by the drawing-in, compressing, 
and exploding of gas produced from gasoline. 

Cylinder and Crankshaft Subgroup. All thb work is actually done 
within the cylinder, which really forms the basic working medium of 
the engine. The actual drawing4n of the gas, its compression and 
explosion are accomplished by the movements of the piston up and 
down in the cylinder bore. The piston is moved upward and down- 
ward by the rotation of the crankshaft except when the explosion 
reverses the situation, and the piston moves the crankshaft, to which 
it is attached by means of the connecting rod. The pbton is made to 
fit tightly in the cylinder by means of piston rings, which are com- 
pressed into slots formed in the outside of the piston for this purpose. 
The connecting rod is forced to rotate by its attachment at the lower 
end to one of the crankpins of the crankshaft, which is held in the 
crankshaft bearings fastened in the crankcase. It is enabled to turn 
slightly at the upi>er, or piston, end by being pivoted on the piston 
pin or wrist pin. For convenience the crankcase is usually made in 
two parts, caUed the upi>er and lower haltes. Sometimes the c>'linder 
is also made with a removable cylinder head, or a smaller removable 
cylinder cover. The majority of modem motors have the valves 
enclosed by removable cylinder talte covers. 

Carhuretion Sub-Group. The production of the gas necessitates 
what b caDed a carburetor^ a good-sized/iie2 tank, and piping to connect 


the two. The fuel is not always pure and must be filtered through a 
strainer. A cock must be provided in the piping for turning the flow 


manifofd. These and other parts, the functions and construction 
of which will be explained in full later on, constitute the carburetion 

Inlet and Exhaust Valves. In order to get the gas, which is 
produced by the carburetion group, into the motor cylinders at the 
proper time and in the proper quantity, inlet valves are necessary. 
These valves are operated by cams on a camshaft. The camshaft, 
which will be explained in detail later, is driven from the crankshaft 
of the engine. After the gas has been admitted into the cylinders, 
compressed, and exploded, it is of no further use and must be removed 
from the cylinders. As this must be done at the proper time, and as 
the proper quantity must be removed, additional valves known as the 
exhaust valves are necessary. These are also operated by cams on a 
camshaft, driven from the crankshaft. 

Exhaust System. The exhaust gases pass from the cylinder 
through a particular pipe, known as the exhaust manifold, and thence 
to the back of the car. As there remains considerable pressure in 
these gases when allowed to escape freely, they make much noise 
and considerable smoke, so that all cars are required by law to carry 
and use a muffler. The exhaust gases pass through this and thence 
out into the atmosphere. This whole group of parts is called the 
exhaust system. 

Ignition System. The explosion comes in an intermediate stage. 
It is produced by means of an electric spark, made within the cylinders 
by means of a spark plug. The electric current, which is the original 
touree of this spark, may be produced by a rotary current producer, 
known as a magneto, or it may be taken from a battery. In either case, 
the current must be brought up to a proper strength, and the various 
sparks must be produced at the exact time they are needed. All this 
calls for auxiliary apparatus. Moreover, the current producer, if it 
be a magneto, must be driven from some rotating shaft, and there 
must be a suitable place provided on the engine to attach it in such a 
way as to provide for quick and easy removal. All this, as a complete 
unit, is called the ignition system. A complete treatment of this 
subject will be found under "Electric Equipment for Gasoline Cars". 

Cooling System. A great amount of heat is created by the fol- 
lowing explosion and subsequent expanding and exhausting of the 
gas. Some idea of this may be gained from the t>vo following state- 


meiits: The explosion temperature often runs up as high as 3000° F., 
and the exhaust temperature frequently is as high as 1500° F, In 
order to take away this heat, which communicates itself to the walls 
and to parts of the engine wherever it comes in contact with them, 
and, by conduction, to other parts with which it does not contact, 
the parts which are exposed to the greatest heat are surrounded by 
hollow passages, called jackets, through which water is forced, or 
allowed to flow. This might be called a collector of the he^t, for it 
is tlien conducted to the radiulor, a device for cooling the water. 
It is there cooled off and then used again. In order to cireulate 
the water, a removable pump, driven from some rotating shaft, is used. 
All this, with the necessary piping to connect the various parts, is 
called the cooling system. 

On some cars, notahlj' the Franklin, and on motorcycles, there 
is another type of engine with an air-cooled system. This type will be 
taken up later. 

Lubricatiim System. To make the various parts rotate within 
one another, bearings, or parts specially designed to facilitate easy 
and efficient rotation, must be used. In and on all such bearings 
a form of hibricant is neces.'Miry. also between all sliding parts. 
Id order to have ii copious supply of oil at certain points, various 


Lighting System. Nearly all modern motor cars have an electric 
lighting system. This includes an electriocurrent generator; a battery 
to retain the electric current until needed; suitable governing devices 
to control the generation and flow of current; lamps to use the current; 
wiring to connect them with the soiwce; switches to turn the current on 
and off; and other parts. 

Flywheel, At one end of the engine shaft is the flywheel. This 
is a large, wide-faced member of metal, comparatively heavy, the 
fimction of which is to store energy (by means of rotation) as the 
engine produces it and to give it back to the engine at other parts 
of the cycle when energy is needed, and none is being produced. In 
short, it is a storehouse of energy, absorbing the same from the engine 
and giving back the excess when it is needed. In general, this effect 
is greatest when the mass of metal is farthest from the center, con- 
sequently fl^-wheels are made of as large a diameter as is possible, 
considering the frame members. Note this in the illustration. Fig. 1. 

Clutch Group. The clutch is generally located inside the rim of 
the flywheel. This is a device, by means of which a positive connec- 
tion can be made with the engine or a disconnection from it effected 
at the driver's will. When such disconnection is made with the engine 
running, it will continue to run idly, and the car will come to a stand- 
still. Conversely, when the positive connection is made, the motor 
will drive the clutch and such parts beyond it as are connected-up 
at the time. This arrangement is necessary because of a peculiarity 
in the gas or gasoline engine which cannot start with a load, but must 
be started and allowed to get up speed before any load is thrown upon 
it. The function of the clutch, then, is to disconnect the balance of 
the driving system from the engine, so that it may attain the necessary 
speed to carry a load. When this has been done, the proper gear is 
engaged, the clutch is thrown in, and the engine picks up its load. 

Like other groups, this must have a means of connecting and 
disconnecting, a proper place, proper fastenings, means for adjust- 
ment and removal, means for lubrication, and easy access to its parts. 
All this, collectively, is called the clutch group. 

Transmission Group. As has just been pointed out, the gasoline 
engine cannot start with a load ; it must get up speed first. When the 
load is first applied it must be light. This necessitates certain gearing, 
so that,, when starting, the power of the engine may be multiplied 


many times before reaching the wheels and applied to the propulsion 
of the car. Furthermore, it has been found convenient to have a 
series of such reductions or multiplications. These correspond to the 
various speeds of the car, for, obviously, if the power is multiplied by 
means of gearing, it is reduced in speed in the same ratio. This whole 
group of gearing is the tTansmiamm or gearsei, and the various reduc- 
tions are the low, intermediaie, and high speed in a three-speed gear- 
box; and low, mtermediale, second, and high in & four-speed gearbox. 
A gearbox is always spoken of by its number of forward speeds, but 
there is in all of them, in addition to the forward speeds, a reverse 
speed for backing the car. 

In the usual form, these gears are moved or shifted into and out 
of mesh with one another, according to the driver's needs. For this 
purpose, shifting gears must be provided within the gearbox, that is, 
the arrangement must be such that the proper gears can be moved 
back and forth, with a shifting lever outside for the driver's use, and 
proper and accurate connections between the two. The gears must 
be mounted on shafts, these in turn on bearings, the bearings must, 
be supported in the gear-case, and this must be supported on the frame. 
In addition, there must be suitable provision in tlie gear-case cover 


mission— to an inclined one — the driving shaft — with as little loss 
as is possible. 

Rear Axle and DifferentiaL The driving shaft drives the rear 
axle through some form of gear, either hevely worm, or other variety, 
and is usually a two-part shaft. The reason for cutting the rear axle 
is that each wheel must be driven separately in rounding a curve, for 
one travels a greater distance than the other. This seemingly com- 
plicated act is produced by a simple set of gearing called the differen- 
tied, which is located within the driven gear in the rear axle. Each 
half of this is fixed to one part of the axle shaft. All these gears and 
shafts must have bearings, lubrication, means for adjustment, etc. 
On the outer ends of the axle shafts are mounted the rear wheels, 
which carry some form of tires to make riding more easy. The 
brakes are generally in a hollow drum attached to the wheels. All 
this goes to make up the driving system. 

Steering Group. The front wheels perform a different function. 
They are hung on the steering pivots, so that they can be turned to 
the right or the left as desired. In order to have the wheels, work 
together, a rod, called the cross-connecting rod, joins them, while the 
motion is imparted to them by means of another rod, called the 
steering link, which joins the steering lever or arm with the right-hand, 
or left-hand steering pivot. The last-named lever projects downward 
for this purpose from the steering-gear case and is moved forward and 
backward by the rotation of the steering wheel in the driver's hands. 

The. transformation of the rotation or turning motion of the hand 
wheel into a longitudinal movement is accomplished within the 
steering-gear case by means of a worm and gear, a worm and partial 
gear, or by a pair of bevel gears. All these parts need more or less 
adjustment, lubrication, fastening means, etc., the complete group 
being designated as the steering group. 

In addition, the steering wheel and post carry the spark and 
throttle levers, with the rods, etc., for connecting them to the igniting 
apparatus (magneto, timer, etc.) and the carburetor, respectively. 
The purpose of the spark lever is to allow the driver to var>' the power 
and speed of his engine by an earlier or later spark, according to his 
driving ^leeds. Similarly, the _throttle -lever is for the purpose of 
opening or closing the throttle in the intake manifold of the carbu- 
retion system and regulates the amount of gas' entering the engine, 


thereby increasing or decreasing its power output, or speed. Actually, 
these are parts of the ignition and carburetion systems, respectively, 
but they are usually classified with the steering group, because they 
are located on the steering wheel and post. 

Frame Qroup. Little need be said about the frame. The side 
merrthers are generally supported by the springs at the front and rear 
ends. The springs are connected to the axles and support the car. 
The/nrntcnMa-memfcerusuaily supports the radiator and sometimes the 
front end of the engine, too. The rear cross^member usually supports 
the gasoline tank when a rear tank is used. The other cross-members 
may support the engine, transmission, shifting levers, and other parts, 
according to their location- In general, the number and character 
of frame cmss-members is slowly changing; the modern tendency 
is toward their elimination. By narrowing the frame at the front, 
the engine can be supported directly on the side members. With the 
units grouped, the same is true of the other important units. 

Formerly, practically all motors and transmissions were sup- 
ported on a sub-frame, but it has been found that the same results can 
he obtained when this extra weight is eliminated. Fig. 1 shows a 

When the shifting levers are placed on the outside, the^' are 




In the following pages, the general grouping just outlined will be 
followed consistently, so that the student and w^orker will be able to 
follow through the construction and repair of the entire car in a reason- 
able and logical manner. 

The principles of engine design, and the methods and details of 
engine construction are second to none of the other factors that com- 
bine to produce the complete modem automobile. 

How automobile engines oi>erate, the reasons underlying the 
various details of different designs, and the relative merits of different 
constructions are all too little understood bv most of those who have 
to do in a practical way with the new conveyance. 

Cycles of Engine Operation. In all motors of any type other 
than those in which there is a perfectly continuous development of 
the power through constantly rotating elements — as in the electric 
motor and the steam turbine — there must be reciprocating elements 
that function through indefinitely repeated series of operations. 
Such a series of oi>erations is termed the cycle of the engine and is 
abundantly explained later in the book. It will suffice here to call 
attention to some of the merits and demerits of the different cycles 
that are in practical use. 

Tiro-Cycle Engines. That t^'pe of internal-combustion engine 
in which everj' stroke in one direction is a power stroke affords a 
fyiA Timiiin of power impulses to any given number of engine revolu- 
tionSy but because of other limitations it is not always possible to 
make m two-cycle engine run as fast as a four-cycle, so that in the 
majority* of cases, the number of explosions in a given period of time, 
or for a given vehicle speed, is no greater with a two-cycle than with 
a four-cj'de engine. 

In addition to this, most two-c>'cle engines are often difficult 
to start. They are likely to be wasteful of fuel, not at all flexible in the 
matters of speed and pulling power, and in various other respects 
difficult to api^y to automobile ser\'ice. Their greatest merit is 
their eztreoie »mplicit>'. 

Fawr-Cyde Engines. The four-c>'de engine is the type by 
wliic^ mne hundred and ninety-nine out of ever>' thousand present- 



day automobiles are propelled. Varied through an immense number 
of possible forms, and with minor differences in the product of every 
maker, its fundamental functioning }ias, nevertlicless, proved to be far 
the most suitable for automobile propulsion. 

With the succession of suction, compression, explosion, and 
exhaust strokes affonled hy tlie four-cycle motor, a very positive 
and reliable functioning is secured ; and by the expedient of a sufficient 
cylinder multiplication to afford good mechanical balance and fre- 
quent power impulses, its flexibility, durability, and practical quality 


four-cyclinder vertical engines as those most suitable for tlie propul- 
sion of the average automobile, as this is the least number of vertical 
cylinders with which mechanical and explosion balance can be secured. 

The use of six cylinders, with the crank throws 120 degrees apart 
and the explosions occurring once for everj- 120 degrees of crankshaft 
rotation, affords a smoother-running motor than the four-c\linder. 

Still better than the "six," from ever>- standpoint except that of 
cost, which has prevented its wider application to automobiles, is the - 
V-shaped, eight-cylinder motor, of the t\-pe illustrated in Fig. 2, 

•VbIvb MoUir 

which gives a good view of the unit power plant of a well-known 
American machine. In both of these, a four-throw shaft, similar 
to the ordinary four-cjlinder crankshaft, is used, is mucli cheaper to 
manufacture than a six-cylinder crankshaft, and the two rows of 
cylinders, each practically constituting a separate four-cylinder engine, 
are made to work upon the common crankshaft at 9(1 degrees apart. 

The most recent tendency in car motors is tow.ird the eight-cylin- 
der V-tj-pe, following the marked success of tills form in aviation use. 

Not only has the V-form been produced in the poppet-valve 
form, but also in the Knight sleeve-vahe type an example of which 



is shown in Fig. 3. Furtliermore, a considerable number of twelve- 
cylinder V-type motors have been built, a good example being shown 
in Fig. 4. 

An answer to the demands of the car owners for the flexibility 
and power of the multi-cylinder types has been recently given by the 
issue of a very flexible and quick starting fourK-ylinder motor with 16 
valves, two intake and two exhaust valves in each cjlinder. Four 
of these of widelj- varjing design have already been announced — 
Stutz.White, and Drexel Motor Car Companies, and Wisconsin Motor 
Company. The (ictails cif the Wisconsin motor are given In the sec- 


cooled and also very light in weight, eliminating all of the parts and 
also the weight in the water-cooling system. The large revolving mass 
does away with the need for a flywheel, while the practical elimination 
of reciprocating parts reduces vibration to a minimmn. 

In the extreme, motors of the V-type have been constructed with 
sixteen cylinders, eight in each group. These have been very suc- 
cessful in aeroplanes and motorboats, particularly the latter. 


Engine Troubles 

Deposits of Carbon in Cylinder. These are loosened by intro- 
ducing two or three tablespoonfuls of kerosene, put into the cylinder 
when warm through spark-plug hole. Replace the spark plug, but 
do not connect up the wires. Turn the engine over slowly to work 
kerosene back of rings. Allow it to stand a few minutes. Then 
connect the wires and start the engine running out of doors, as dense 
smoke will come for a time. Clean spark plugs and replace. 

Knocking. Knocking should not be permitted. It is likely to 
result in injury to the engine. Ordinarily, knocking is avoided by 
retarding the spark. In starting up a hill where considerable power 
will be needed, an open throttle with advanced spark should be 
employed before beginning the climb. Should the motor begin to 
knock when part way up the hill, the spark should be gradually 
retarded. Continued pounding is caused by the connecting rod and 
main-shaft bearings becoming loose. 

Failure to Start. Try the following remedies: 
See that current is switched on. 
See if throttle valve is open. 
Be sure gasoline tank is filled. 
Be sure gasoline valve is open. 
See that air can enter filling cap of gasoline tank. 
Flood carbui^etor. 
If weather is cold, prime cylinders by squirting a little 

gasoline in through each compression relief cock. 
See that spark plugs are clean. 
Missing of Explosions. See "Troubles with Ignition System." 
Popping in Carburetor. Snapping or popping in the carburetor 
is caused by lack of gasoline, so that the mixture fed to the motor is 


not rich enough, and as a result it burns so slowly that one of the 
admission valves may be open before the charge is completeiy billed, 
and part of the burning charge is forced back through the pipe. lead- 
ing from the carburetor to the combustion chambers. If adjustment 
of carburetor is such that a weak mixture should not occur, inspect 
the gasoline l>iping system carefully for an obstruction. Popping in 
the carburetor may also be caused b.\' a leaky Joint in the piping and 
by connections between the carburetor and the combustion chambers. 

Poor Compression. A'ahe stem ma,\- be broken and stickius- 
Valve spring or ^alve stem ma,^- he clogged with dirt. Cylinder or 
explosion chamber may be cracked. Piston rings may be broken or 
turned so that cuts line up, allowing prtssure to escape. Cylinder 
may be giminmi. Cam ma\' be loose. AVater ma,\' leak into cylinder 
through plugs in cylinder head. Valves may not seat properly due 
to being covered with soot. A'aKes may ha\'e to be reground. 

Engine Starts, but Stops, after a Few Revolutions. Engine bear- 
ings may have seized fnim lack of lubricant. There may be too 
much oil in crankcase. Water may be entering cylinder througli 
■ cracks or thnjugli plugs in cylinder head. Carburetor float may be 
sticking. I'uor water circulation may be due to broken pump shaft 
or clogged water piping. 

Flf. 6. Elufliiw DiHDouat«d, Sbowiug CyUoden Itemovcd 



off. When this \s done, the appearance of the ve^hicle and of the 
work is very much Hke that presented in Fig. 5, which shows two 
men engaged in loosening up certain parts of the engine preparatory 
to taking it out. 

When all accessories have been removed or loosened up, the 
holding bolts are taken out, the clutch disconnected, and the motor 
is left free to be swung out by means of a small crane or hoist. In 
some cases, the work can be completed without disturbing the base 
■ of the motor, as in Fig. 6, which shows a big car partly disassembled 
for repairs, the radiator and cylinders having been removed at this 
stage. The trouble here was found within the cylinders, hence, 
as soon as they had been removed, the balance of the six-cylinder 
motor and its chassis could remain undisturbed. 

Hoists and Cranes. Yale & Towne Form. For lifting out an 
engine or other unit approximating several hundred pounds (possibly 
500 pounds In tlie case 
of a big engine) an effi- 
cient form of overhead 
hoist is needeti. There 
is nothing better than 
the Yale & Towne 


would complicate the job. When hung, any crane, hotst, or any block 
and tackle, can be hooked into it and when the load has been lifted 
clear, it can be run along the track until the desired point is reached. 
IF this expense is top great, the same results can be obtained 
by taking a sliding-door track and suspending it from the ceiling 
beams. Then the two door carriers can be joined by the large end 
of a V-shaped piece of steel, not less than } inch by 2 inches in section; 
while the carriers are separated and held separated by a simple straight 
distance piece. The lower end, or point of the V, supports the 
hook or eye, whichever is used. That is, from an old sliding door, 

High 01 

a traveling hoist can be constructed easily and quickly to handle 
engines or other large and heavy units. 

Floor Type of Hoist Support. When the construction of the roof, 
or ceiling, is such that it will not permit a suspended hoist, one which 
works from the floor can be constructed. This consists, as Fig. 8 
shows, of a double track beam supported on castor-mounted triangu- 
lar ends, which extend as high as the garage will allow. By this 
means, the weight can be lifted clear, and the entire structure move<l 
to the desired place. It is constructed a good deal like those \\iaX. 


described; the ends are fair sized angles, say 2 inches by 2 inches 
by jV inch; the braces lighter stock, say IJ inches by IJ inches by 
^ inch; and the castors are anything that ts available. It is not 
necessary that the track be metal; wood can be used if it is wide 
enough to withstand the wear of the wheels and deep enough to 
carry the heavy loads. 

Commercial Forms. If sufficient money is available to purchase 
a hoist, these makeshifts are, of course, unnecessary. There are a 
number of portable cranes for garages on the market, costing from t90 
up. These usually have a U-shaped base of heavy cast iron with 
two caatora at the points, and one 
at the back of the U. At the back 
also is a vertical pillar about t 
feet high, with a curved exten- 
At the end of the extension 
is a grooved pulley carrying a 
chain hoist. The crane runs back 
to a sheave and set of gears for 
winding it up. It has a suitable 
:lle for this, as well as a long 
ing handle for moving the 

I i>.B'Stul 



round stock, put through the drilled holes in the upper or supporting 
bar, then bent over and shaped. Before anything is done, the ends 
of the bars must be turned down and threaded. In this instance, 
there is a hole at the four points on the shelf of the motor, so these 
holes govern the size of the ends of the rods and also their spacing. 
On almost every motor, there will be some means of attachment which 
can be studied out in advance, and the rig built to fit it. 

Portable Engine Stands. If the engine is removed from the 
chassis, the first thing needed is a suitable engine stand. One of these 
is shown in Fig. 10, a form that can be purchased at a reasonable 
price, and which possesses many excellent features, The frame is made 

SuriitifiM. OSio 

of tubing, which gives a maximum of strength in a minimum of space. 
The oil drip pan beneath is a good feature, as is the shelf arrangement 
at the open end. The large castors allow it to be moved around readily 
and can be clamped to hold it any place. One can be constructed 
out of heavy galvanized pipe and pipe fittings at a moderate cost. 
This form of engine stand holds the motor in its natural, orupright, 
position. But it is not always desirable to have the engine in that 
position ; in fact, when working on crankshaft bearings and other parts 
on the under side, it is necessary to have it inverted. There also is 
work which makes an intermediate position desirable. For this 
purpose, an engine stand is needed which can be turned to any desired 


angle and fastened there. Such a stand is shuwn iu Fig. 11, which 
represents one made liy the Internationa] Motor Company, Plainfield, 
New Jersey, for its own use. It would hardly paj' to make one of these, 
as the ends are castings which require a pattern, but if a couple of 
garages wanting, say two each, would go in together, it would pay to 
have patterns made for the four. After making castings for their own 
frames, the garage owners could later make them for sale if they 
wanted to go into the business. The sketch explains the construction, 
butthis explanation might be addetl: the central part, projecting from 


. aluminum alloys has commended them for aviation use and in some 
cases For racing automobiles. 

Method of Classifying Cylinder Forms. Cylinders are generally 
named according to two things: first, the method in which they are 
cast or produced; and second, the shape of the combustion chamber, 
or arrangement of the valves. Thus, according to the first method, 
they are divided into those which are cast separately, that is, each 
cylinder by itself; cast in pairs, or each two cylinders cast together; 
cast in threes, a modem modification fitted to the six-cylinder engine; 

and cast together, or en bloc, that is, all of the cylinders cast as a 
single unit. 

According to the second method of naming, cylinders are of the 
L-head type, in which the combustion chamber has the shape of an 
inverted capital letter L, formed by the placing of all valves on one 
side; of the T-head tj-pe, with the combustion chamber shaped like a 
capital T, because the valves are equally distributed ; of the I-f ,vpe, 
or valve-in-the-head type, so called because the combustion chamber 
is left perfectly straight and round by placing the valves in the head; 
and modifications of these. 



Usually in speaking of the cylinders, both namea are used as one, 
as, for instance, those of Figs. 2, 3, and 4, all of which happen to be 
aHke, would be spoken of as L-head blocks. Figs. 12 and 13 as T-head 
pairs, etc. 

Methods of Casting Cylinders. Cast Separately. The early and 
still common practice in the building of multi-c\' Under gasoline motors 
is the casting of cylinders separately. This policy makes it easier to 
secure sound castings, simpler to machine and finish them, and less 


water jacket of sheet meta^ of the buitt-on form. These have shown 
splendid cooling abilities, but, under the twisting and racking of 
automobile frames, particularly in later years, with the use of more 
flexible frames, they have shown too much tendency toward leakage 
to become popular. 

Cast in Pairs. Just as soon as two-cylinder and four-cylinder 
engines were produced, the cast-in-pairs form of cylinder appeared 
and is almost as widely used today as then. While the modem 
tendency toward smaller bores, compactness, and light weight has 
greatly increased the number of cylinders cast en bloc, the paired 

. jl i^^ft. 








Studf bkkcr Sii-Cylinder Motor. Sho<ri: 

form, including the cast-in-threes modification for six-cylinder 
engines, holds its own. 

Cast Together. The great advantage of having the several 
cylinders of one motor cast together — en bloc, as the French term it — 
is that the alignment and spacing of the different cylinders is thus 
rendered absolute and permanent, regardless of any differences in 
adjustment that may otherwise occur in assembling. 

This construction has been applied to a large proportion of the 
small and of the medium-sized fours, a fair proportion of the larger 
fours, and to a considerable number of sixes, Fig. 14. 




Another advantage is, that the water connections, exhaust and 
intake manifolds, etc., are rendered simpler both in their form and 
the mmiber of their points of attachment. 

In some advanced motor designs, the passages for the incoming 
mixtm« and for the exhaust gases, and in one case even the carbu- 
retor itself, are all incorporated in the main casting. 

Pit. 18. Section threucb Typienl L-Hosd CylindBr with Vilve 

Puta in Place 

Cmrtwt ti On aUtm Mitor Cv Ctrnfcnt. DHnil. Itirliifm 

Another example of simple construction is that illustrated in 
Fig. 15, which depicts one of the latest Ford motors, in which cylin- 
ders, upper half erf the crankcase, and the gearbox are all cast in one 
piece. The lower half of the crankcase and gearbox are similarly 


constituted of another simple pressed steel unit, while a second casting 
is iiseil for the heads of the cylinders and for the water connection. 
Cylinders Classified as to Fuel Chamber or Valves. L-Ilead 
Forms. In the L-head form, the valves are all located nn one side, 
and usually hecause of this, all the accessories are on the same side. 
This makes a lop-sided engine, with carburetor, inlet pipe or manifold, 
magneto and wiring, exhaust 
manj/old, and sometimes elec- 
tric generator and other parts 
all grouped on one side, with 
little or nothing on the other. 
While a disadvantage in four- 
and six-cylinder motors, this 
is somewhat of an advantage 
in eight- and twelve-cjlinder 
forms, for all the parts and 
auxiliaries ran be grouped in 
the V between the cylinders, 
leaving the outside clear. On 
the other hand, where this 
grouping has been found unde- 


Ilf. IB. AluBUBum CMting Sat Cylinden aod Upper Half oF CtuikcH« ja Mumon Ensiiie 



out w itlutUud tin; lifrtt. well, and consequently »liuuld be far away from 
xii& lutat (if thu t-xtiuust manifold. See Figs. 12 and 13. 

/- Ueatt Furiim. The valve-in-the-head, or overhead valve, motor 
require-ti an 1-hnad cylinder, because, with this location of the valves, 
there is lit) HoivMsity for the valve pockets of the other forms. Con- 
i>etiui!iitly the cylinder can be straight and plain, while the head, 
which ia sc|iariite, is fastened on instead of being cast integrally. 
It may have either the L- or T-form, according to the location of the 
valveti and the inlet and exhaust manifolds. Fig, 1 7 shows an I-head 
in which the manifolds are 
.tcated on the opposite side. 
Note that in this form the 
c\iinder head is integral, the 
valves being set in cages 
which are removable, as 
shown in the view of the 
Interstate Motor, Fig. 18. 

The foi 

clearl\- separateti as they 

were fomierlj-, for the inelu- 

of cylinder heads 



Cylinder Repairs 

Remova] of Carbon. One of tRe things every repair man must 
do is remove carbon. A good method is the introduction of a metal 
object, as a ball or a piece of chain, which the piston is allowed to 
bomice up and down to break up the carbon. This is successful, 
but there is always the danger of the part getting under a valve or 
other part, and causing trouble. 

A better way is to couple up a number of short lengths of'chain — 
old tire chains will do — and attach them to the flexible shaft of a 
buiSng or polishing outfit, as shown in Fig. 21. This chain and 

shaft end can then be introduced into the combustion chamber 
and, when the current is turned on, the rotation breaks off all carbon. 
Carbon on Fired Cylinder Heads. When the motor has fixed 
cylinder heads, and the valve opening is small, this is not always a 
good way. Another somewhat similar tool can be constructed to go 
in through the bore of the cylinder and clean off the cylinder head very 
nicely. This b shown in Fig. 22, at work (at right) and in detail 
(at left). It consists of a round steel brush with very stiff wire 
bristles mounted in a four-cornered frame. The latter should be 
smaller than the cylinder bore by } inch or so, but the bristle 



circle should be full diameter. When rotated by means of a flexi 

shaft, the outside bristles have a* tendency' to throw outward, ao tl 

this device will clean a space considerably larger than its diame 

when at rest. 

AV,';t:^r*r^_^^ ^Mien the elect 

-'^^'' motor, or electricity 

furnish power for i 

device shown in Fig. 

is not available, ^mi 

results can be obtair 

by attaching a geai 

hand drill, as shown 

Fig. 2.3. When this 

used, however, it is di 

cult to attain suffici* 

speed to expand 1 

chain, so a wire bn 

with fairly long wi 

nill be found bet 



/?//- Sup ply "i 

wire — long, ^hort, and medium — will come in handy, also brush ends 
with various . diameters of shank, with copper tubing around the 
actual shaft, or flexible tubing. This can be inserted more readily 
than the chain "mop" shown in Fig. 21. But, as stated above, it 
cannot do equal work, because it cannot be revolved so fast. 

Compressed Air. If the cleaning periods for the engine are not 
too far apart, the greater portion of the carbon can be blown out with 
compressed air by using the air after a chain "mop" or wire brush 
just described. To use the air; however, calls for a special fitting, 
two of which are shown in Fig. 24. The one at the right is the most 
simple, but the one at the left has the advantage of being made from 
pipe fittings instead of from brass tubing. Both screw into the opening 
in the center of the cylinder head, and the air enters through the 
central hole, while the 
carbfm is blown out 
through the larger annu- 
lar opening. 

Liquid Solvent, 
Nowadays, carbon re- 
moval is often accom- 
plished by means of liquid 
solvents. Of these, ker- 
osene, denatured alcohol, 
and special preparations 
are the most widely known and used. Kerosene is used when return- 
ing from a trip. Just before stopping the engine, it is speeded up 
and a little kerosene inserted into each cvlinder. This loosens the 
carbon so that it blows out through the exhaust. 

Denatured alcohol and also the special preparations are used 
in much the same way, except that the engine is not run. After 
returning to the garage, and while they are still hot, an ounce or so is 
placed in each cylinder and allowed to stand there over night. On 
starting the motor the next morning, the loosened carbon is blown 
out through the exhaust pipe. If the carbon is very thick, more 
alcohol must be used and allowed to stand for a longer time. By 
rejx'tition, this will gradually clean out all there is in the cylinders. 

Removing Carbon by Scraping Tooh. When all other means of 
removing the carbon fail, the repair man must go back to hand 

Fig. 24. Set-Up for BlowinK Out Carbon from Cylinder 
Heads after Looseninf; 



serapers. In any case, these are the most simple and fully as 
effective as any ; provided the extra time needed to use them and do a 
good job is available. When the offending member has been brought 
out so it can be handled, the removal of the carbon can be accom- 
plished in a few minutes. A flat piston head, like that shown in 
Fig. 25, can be scraped off with any knife or chisel, but a special 
scraper nia<le from an old file, flattened out at the end, and ground 
down so as to present one sharp edge is better. Every garage man 
should accumulate from five to a dozen shapes and sizes of scrapers 


at the top, A,ia& plain straight scraper with a hooked end. Where 
there is plenty of room to work, this is the usual tool. That at B is 


I'uHdiu Typea of Cvbon Scnpen 

somewhat similar, except that the length is greater, and the end is 
bent. This allows of getting up or down further than with the straight 
tool. A form with a double bend, no handle, and a scraper at each 
end is shown at C. The advantage of this lies in getting around 
cur\'e3 and comers. Still another at D has the same curves and a 
^milar double curve in the other direction; this also allows working 
into deep corners. That indi- 
cated at E, with a shape like a 
hoe, is made that way to conform 
to the upper curved surface of the 
ordinary combustion chamber and 
the flat top of the piston. The 
handle screws in, and to insert the 
tool in the motor, it is taken 
apart, and parts put in through 
separate holes and assembled or 
screwed tt^ther inside. The 
fonn at F is particularly suitable 
to the eight-cylinder Cadillac 
cylinder head, but may be used 
with any motor having a similar 
design. It is a rotary form, the 
central plug being screwed in, to replace the cylinder-bead plug. 
Tbe rotation of the handle outside causes the tool inside to tura 

Fig. 27. Cor 

CyUndri. . 

ud Spu-k Plug SfacU 


around over the surface of piston top and combustion chamber. 
When used against the top it is pulled upward. It is pressed down 
when used against the bottom, or the piston. Other special forms 
will be constructed by tlie clever workman for certain motors having 
peculiarities which make these specials desirable and time-saving. 

Covtpress'ion Indicating Gage. Before taking off tlie cj'Iinder to 
look for trouble inside, the repair man should do all he can to find out 
what and where the trouble is. A conjpression gage is handy, as 
this indicates the pre,*^ure in e;i(.li <■} llinlcr. Thr-e sliould nil agree 


which nine persons out of ten would blame to the carburetor. This 
gage will show up these leaks. 

Locating Noises by Means of a Stethoscope. Besides this, it 
should be borne in mind that there are many sources of noise in 
and on the engine other than that produced by valves and valve 
motions. In fact, the noises made by the valves, while an indication 
of loss of power, do not represent anything like the possibilities for 
trouble, indicated by a piston slap, a crankshaft or connecting-rod 
pound, the whirr of worn timing gears, and others. In order to locate 
such sources of noise exactly, at a time when the beginner lacks famil- 
iarity with the motor and its troubles he should purchase or borrow 
and leam to use a stethoscope. Fig. 28. A modification of the sur- 
geon's well-known instrument is now made for use in automobile 
trouble finding. 

The stethoscope, or its modification, simply magnifies all noise; its 
constrdction is such that one end is held against the suspected part, 
while the other end constitutes an ear piece. When the engine begins 
to make a great deal of noise, particularly heavy pounding noises, this 
should be brought into play. With the motor running, place the free 
end against the various parts of the engine, going slowly from one 
to another. In this way it will soon be found where the trouble lies. 

A piston slap is not so easy to define or so easy to repair. It 
may be called a noise which comes from within the cylinders, trace- 
able to the pistons, or to one piston, as the case may be, which 
sounds very much like a sh^ft pound, except that it is a louder noise. 
It occurs when pressure is put on the piston, as at the beginning of 
compression, at the time of explosion, or at times at the end of each 
stroke. It is said to be due to different causes. Some say it is 
caused by a loose piston pin, but the writer knows of two cases in 
which a new tight pin left the piston slap just as clear and distinct 
as before. Others say it is caused by rings which are loose up and 
down in their grooves, but in the cases above, new rings which fitted 
tightly in this way did not help any. It has been ascribed to a piston 
which was out of round, so that it did not fit the cylinder, and also to 
a groove and shoulder having been worn in the cylinder surface, the 
piston striking this each time. Whatever is the real cause, and the 
writer is inclined to blame it to a poorly fitting piston, nothing will 
really remedy it but a new piston^ complete with rings. 


Making Gaskets. Anyone who is going to do much repair work 
will soon liii\e to learn tlie art of making gaskets, for, in almost every 
case, the removal of a pajjer gasket is accompanied by its breakage, 
so it is rendered unfit for furtlier use. A gasket, it might be explained, 
is a formed sheet of hea\y paper, cardboard, or special material fitted 
between two surfaces of a joint wJiich must resist the leakage of gases 
or Hquids under pressure. By means of the bolts or screw threads 
which hold the two parts of the joint together, the gasket is com- 
pressed and, in its compressed state, it resists the internal pressure. 

The following method of making gaskets applies alike to round, 
oval, and odd-shaped ones, which cannot be said of special tools and 
fittings for gasket cutting : Select 
a good piece of heavy brown 
wrapping paper or special gasket 
paper without too many WTinkles, 
free from cracks or flaws. 
Clamp the part for which the 
gasket is to be made in a vise to 
steady it and lay the paper over 
it. Then go around the edges 


CyUnder Heads. A great many motors have detachable heads, 
and their quick remo\-a] is a great convenience, when there is carbon 
to be scraped off, pistons to be looked over, or other internal work 
to be done. However, replacing them is never quite so easy as 
remo%'ing them, partly on account of the cylinder heads themselves 
and partly on account of the pistons. The latter are particularly 
troublesome when the cylinder head is hinged. The cylinder head 
should be repUtced with great care, and after replacement it is fully 
as important to bolt it on property. 
It one bolt or a series. of bolts is 
tightened too quickly and too hard, 
it is likely to result in cracking the 
cylinder casting or the head casting 
or both. 

Proper Method <^ Boiling on 
Head. Usually, on an L-head tyjte 
of motor, there are three rows of 
bolts for the cjlinder head — one row 
along the middle, screwing into one 
side of the cj'linders; another row 
screwing into the other side of the 
cyUnders; and a third along the valve 
^de. These should be tightened in 
order: first the middle bolts of the 
middle line, working out to the ends; 
next in turn, the middle bolts of the 
back of the cylinder, the middle bolts 
of the valve side, the ends of the 
cvlinder; and finally, the end bolts on p^ 30 
the valve side. All these should be m-«h=. w.™ cyiind«'Bo™r 
tightened but a few turns at a time, and after all are down, a 
second round should be made in about the same order, to give 
each bolt a few more turns. In this way the cylinder head casting, 
which is both large and intricate, is slowly pulled down to the 
cylinder straight and true so that it is not warped or twisted. More- 
over, if tbe cylinder is pulled down straight in this manner, all the 
bolts can be tightened more than if the first bolt were tightened ver>' 
mudi, ftH" tbe latter would result in cocking up the opposite side. 




Checking Up Cylinder Bore. Before any work is done upon the 
cylinder bore, sin.'h as turning, uriiiding. etc., It shoultl l>e checked up 
very carefuilj-. An expert workman, accustomed to the tool, would 
use an inside micrometer, but when this tool h Jacking, as well as the 
experience necessary to use it, a fairly simple too! which can Iw used 
by almost anjone may be constructed as follows : Aa shown in Fig. 30, 
a short angle iron forms one side of the bore-measuring part ; its length 
is sufficient to keep the entire tool perfectly ;ertical when the c\linder 
is vertical, and thus gives an accurate right-angle measurement of the 
bore, A central arm is fastened to this and the framework adjustably 




the micrometer could be improved by eliminating the adjustable 
feature and making the frame and angle face a solid piece. 

Grinding Out Cylinder Bore. As the usual amount of metal 
which would be removed from a worn cylinder would not exceed a few 
thousandths of an inch, grinding should be the process used. Other 
procesaes, except possibly lapping or hand grinding, are too inaccurate. 
For this reason, a typical grinding set-up is shown in Fig. 31. This 
shows the cylinder bolted against a large angle plate, attached to the 
grinding machine table. The angle plate is drilled out to take the 
bolts which hold the cylinder casting to the crankcase. When bolted 
up for work, the air hose is connected up through the cylinder head 
to blow out the dust or particles ground off. Not more than three or 
four thousandths of an inch should be taken off at one time; if more 
must be removed, a second operation over the surfaces is necessarj-- 

If the cylinder is worn badly enough to warrant re-boring, which 
calls for new pistons and rings, it should be borne in mind that a 
standard set of oversizes has been adapted by the Society of Automo- 
bile Engineers, and that all manufacturers are working to them, by 
stocking pistons and rings according to these dimensions: 

Oversize Standard 

Inche* Large 

For 1st Oversize 10 thousandths {.010") 

For 2d 0\'ersize 20 thousandths {.020") 

For 3d Oversize 30 thousandths (.030") 

For 4th Oversize 40 thousandths (.040") 

Methods of Cylinder Lapping. When the cylinder must be 
lapped or ground out to a true surface, not re-bored, and when no old 
piston is available for 
this purpose, there are 
several methods avail- 
able. One is to use a 
standard lead lap, that 
is, a 9c^ round bar of 
cylinder size. The abra- 
sive may be either emery 
and oil, carborundum 
dust and oil, or, in some cases* ground glass and oil imbedded in 
the soft surface of the lead, yet it projects enough to abrade the 




cylinder surface a little at each revolution. Another good way of 
doing this is to use a round block of wood, aa shown in Fig. 32. This 
is made a close fit in tlie cylinder, with spiral grooves cut in its surface, 
and a split along one side. Into the latter a wedge is driven to adjust 
for wear. The emery and oil is put on the surface, and the lapping is 
done as usual. The spiral grooves distribute the abrasive evenly so 
that a true surface results. 

Another way of doing this is to make a large special boring bar, 
say 2 inches in diameter, and drill a hole into this at right angles. 
Then, a small round section of carborundum, say J inch in diameter, 
is placed in this hole with a spring back of it to keep it up against its 
work. This arrangement can 
BCijltndcr Motor^^ - |^ „,5j „„ , ,„the, the bar 

being rotated in the usual way, 
and the cylinder fed up to it 
either by the carriage feeder 
by hand. It will give a very 
fine cylinder surface, and use 
up very little of the carborun- 
dum, which costsvery little to 



extended end is that a very minute movement of the piston is mag< 
nified and shown as'a considerable movonent at the end of the wire. 
Thus, it is possible to determine the dead center point very exactly. 

Repairins Cracked Water Jackets. Ver\- often the first cold 
spe)! of faU niU catch the owner napping in the matter of heat for 
his motor, and will freeze up the water, which finds a weak spot in the 
water jacket and cracks it. When the crack is smaU and localized, 
it can be repaired very simply as follows: Drill each end of the crack 
as shown at A and B, Fig. 34, and screw in small J-inch brass plugs to 
prevent the crack from spreading. Then cut back the outer sides 
of the crack with a small cold chisel to permit inserting a considerable 
amoimt of rusting compound, being careful not to cut away any 
quantity of good metal. Then fill the 
crack up very fully and carefully with 
the compound consisting of two parts ir 
filings and one part sal-ammoniac. Just 
enough water should be added to this to 
make a paste which can be handled better 
than the dust or powder. After inserting, 
let the cylinder stand for a day or two, 
and if it does not seal up quickly and 
entirely, add a little water. If this does 
not complete the job, it may be necessary 
to go over it again, adding more of the 
rusting compound. After a couple of tries, 
almost any skillful repair man will get the hang of this job, and be 
able to seal a water jacket crack perfectly every time. 

WeMing Breaks in Cylinders. Welding is used ver>' frequently 
now on cylinder breaks, probably more than any other method, since 
it has proved to be quick, accurate, and cheap. It has ail the 
desired qualities, which cannot be said of any other process. More- 
over, it can be used with almost any form of metal, which also cannot 
be said of any other method. A separate chapter deals with welding, 
very exhaustively. It is recommended that every repair man study 
it; then get an outfit and learn to use it, for it represents a source of 
large profit when its use is once mastered. With a welding outfit, 
the method of procedure is often the reverse of other processes. Thus 
when a water jacket is cracked, the first operation is generally the 

Flc. 34. 



cutting away of sufficient metal to enable the workman to see the 
whuk- extent of the erack and also to permit getting at all the surface 
with the welding torch. With a crack of small size, such as that Just 
described, cnougli of the sides should be cut awa.\' to allow working 
the torch in between them. This crack should be gradually refilled 
with new solid metal, melted in from a fuse bar or melt bar. The 
sides should be cut awaj' so as to take off more on the inside if possible, 
as this gives the new metal a natural hold on the inside in addition to 
the fusing together of the old and new metal. 

When the crack is larger, but still not a big one, as a small curved 
or circular shape, say 2 inches long, a formed steel plate can very often 
be cut which exactly fits around and over tiie crack. This is then 
welded into place. This steel-plate method is particularly effective 
where the pieces of the water jacket are cracked out in chipping the 
hole or crack, or when a. single 
piece to be welded is broken 
into two or three pieces dur- 
ing the chipping. Another 
similar water jacket crack 
repair is that necessary when 
■ylinder water 



Another cylinder weld frequently met is a flan^ cracked around 
a holding bolt. In such a break the fracture is usually confined to the 
flange, no part of the cylinder wall being broken or cracked. Thus, 
all the repair work is external, and proceeds more easil>' and quickly 
than would be the case when dealing with the more accurate cylinder 
wall. This is a simple repair, and is performed entirely from the 
outside by cutting the crack away on both sides to allow new metal 
to be added without increasing the thickness, then setting the piece 

id ol Rc-A»enibLing 

carefully in place, damping it there and fusing new metal from a melt- 
bar into the V-slot formed by chipping. In case the crack does extend 
to the cylinder walls or bore, it is advisable to stop the weld about 
iSr inch from the interior surface of tlie Ixtre. In this weld, as in 
previous ones, excess metal is left on the outside; in fact, this is done 
whenever and wherever possible, as the excess metal compensates 
for the somewhat brittle character of the weld and guards against a 
recurrence of the trouble by making tlie break stronger than it was 
iu the first place. 


Working in Valve Cages. In overhead valve engines, when the 
valves are set in removable cages, it is often necessary to put in a new 
cage. This is worked in or seated in the cylinder by grinding it down 
to a perfect seat the same as a valve. Oil and emery are placed on 
the seat in the cylinder, the cage set in place and gradually worked 
around and down, until a perfect surface is obtained. The same is 
applied to renewing the seat when a valve cage shows signs of leakage. 
Replacing Pistons in Cylinders. When cylinders or pistons 
have been removed to be worked on, replacing these is a difficult job. 
There are two ways of doing tliis: viz, by a special form of ring closer, 
and by hand, usin^ a string. The former is a shaped device which 
is clamped around the ring and squeezed 
together with pliers, using one hand, while 
with the otlier hand the ring is guided 
into the groove. The secxjnd and more 
usual method is illustrated in Fig. 36, and 
requires two men, unless the cylinder is 
of such a shape that it can be clamped 
in a vise. As the picture brings out, 
one man holds the cylinder while the 
?r forces the piston carry 




and is flanged over at the top to give it extra stiffness and prevent 
its entering the cylinder. It is tnade a little bit small for the size of 
the pistons over which it is to be used, so it will have to be sprung 
into place. When this is done, it will have a tight hold on the rings, 
compressing them so they will enter the cylinder. In applying it, 
care should be used to put it on squarely, and similarly in pushing it 
down by forcing the piston upward into the cylinder, as it should not 
be moved off of a ring until that ring has been entered in the cylinder 
enough so it is held therein. That is, the spring clamp should not be 
moved down below a ring until that ring is engaged and held within 
the cylinder. Its use is restricted to one size of motor, which is no 
hardship in a big shop where one make of car is handled exclusively. 
The small shop handling a variety of work would find half a 
dozen different sizes useful and 
economical. Moreover, the cost 
of this device is very small. 

A modification of the above 
device consists of a similar small- 
size band of sheet metal, made 
very w ide, but without the upper 
flange. It is made, however, with 
a pair of right-angle lips where the 
two sides meet, these are drilled 
for a clamping bolt. This bolt 
has a wing nut with clamping rings to compress the lips. Another 
modification of the above is a loop or strap of narrow sheet metal 
having an additional loop to go over the two ends. These ends 
are made with a right-angle bend close to the piston-curve portion, 
and the compression of the rings is effected by pressing the sides of 
the clamp tightly against them, then sliding the small loop along the 
ends to hold this tightness. 

Rigging for Replacing Piston. In motors of the detachable-head 
type, like the Willys, the Chalmers, the Briscoe, and others, the 
work of replacing the pistons, particularly if the crankcase is 
cast integrally with the cylinder block, is considerable. In fact, it 
is sufficiently difficult to warrant making a special jig for guiding the 
pistons down into the long cylinder bores; this fastens onto the top 
of the cylinder where the head belongs. 

Fig. 38 

A Simple and Easily Made Jig for 

Replacing Pistona in Detachable 
Head Motors 


As shown in the sketch, Fig. 38, the jig consists of a round shell, 
the interior of wliich is at tlie bottom of the same bore as the cyl- 
iniier, but flares out considerably at the top. The base consists of 
the flanKe needed for turning this in the lathe and may be of an\ 
shape, size, and thickness. The action of the enlarged diameter at 
the top, gradually tapering to the exact cylinder size at the bottom, 
is to hold the piston rings in place and slowly contract them as the 
piston is lowered, so they pass down into the cyUnder bore without 
trouble. One casting must be made for each cjlinder bore, but the 
time and trouble which they save, and the injuries to workmen and 
parts which they avoid, make them well worth while. 


Piston Construction. The pistons of automobile motors have long 
been made of oast iron, with the piston pin held In bosses on the piston 
walls. For all onlinary service this construction, well carried out, 
serves every purpose, but with the development of very high-speed 
motors, with piston speeds twice and three times as high as past 
practice has sanctioned, there is a growing tendency to substitute steel 
for cast iron in this imjiortant reciprocating element. 

Particularly in a\ iitti<m motors has this been the case; the pistons 



done with new fonm. The lightening of piston weight has not 
materially changed the old open-end trunk form, although the use 
of aluminum bas modified its straight shape somewhat in the hour- 
glass and similar forms. Attempts to utilize so-caUed free pistons, 

Fif. 39. Old and Nfw Typt« of PutQU 

Former Hnvy Pigton M Left; Prcwnt Lighter Type at Richt 

Cnrlrry iif Lotomobile Campaitg of Amiriea. BrUitporl. Coniiaefuiil 

in which the upper part is flexibly connected to the lower, and the 
use of combinations of pressed steel and other metab have done 
much to modify the general form. 

Both these tendencies are well shown in the illustrations, Figs. 
H9 and 40. The former shows how a. certain piston was lightened by 
taking out two rings at the top, one rib inside, and generally using 
thinner metal. The old form is shown at the left, the new at the 
right. The other tendency is seen in Fig. 40 
which is an atutninum alloy. Note how this 
is cast to have less metal at the piston boss 
and also to be strong without extra ribs. 

Characteristics of Piston Rings. Cast 
iron for piston rings, long used to the exclu- 
sion of everj'thing else, is in slight degree 
yielding its pre-eminence for this purpose 
also. This is because it has been found, in 
aviation motors with steel cylinders, that 
bronze affords greater durability and 
smoother running against the steel-cylinder 
wall, for which reason bronze rings — with steel or cast-iron springs, 
or "bull rings", behind them — have been found most advantageous. 
Multiple rings, three or more in a groove, are finding favor. Theic 
thinnesa necessitates the use of steel. 



Types of Piston Rings. Where formerly three or four plain rings 
were used, each one filling a groove, many pistons are now equipped 
with multiple rings of various patented forms, for which many 
advantages are claimed. Some idea of the variety of these may be 
obtained from Fig. 41 which shows a number of different forms. 

Thus, A indicates a ring with a double form, yet really it is one 
continuous piece, cut so as to appear as two. It is difficult to see any 
advantage in this, while it is much more expensive than the old- 
fashioned form. At B is seen a type which has an outer thin but 
high ring within an L-shaped inner form, both with plain vertical slots, 
and without holding pins of any kind. A somewhat similar form is 
seen at C, but with this difference, the inner ring has two steps 
instead of one, both have diagonal slots, and a pin keeps the outer one 
from turning. 

The form at D has a pair of thin and very flexible high rings, set 
one within the other. They are concentric, and both have stepped 
joints. The extreme flexibility would appear to take all the value out 
of their use as compared with the ordinary form. Another seen at K 
differs in that one part is placed above the other and hekl from rotat- 
ing by a pin. Both have diagonal joints. Both are eccentric and 
the pins hold them so the slots are 9() degrees apart. In the form at /', 
there are three pieces, including an inner one of full height with a deep 
outer slot, a modified U. The two outer parts are L-shaped and the 
L-projections fit into the slot of the big ring. All have diagonal slots 
and are pinned in place. 

An eccentric form, whidi has a tongue-and-groove arrangement at 
the open or thin end, is showii at G, The makers call this the lock 
joint. PracticaJly the same effect is produced in the form shown at //, 
except that the opening is closed by a separate piece. This is caller! 
a guard, and it is machined to fit under one portion of the master ring 
and on either aide of the slender ends, so that it makes up the full 
width. This use of the old-fashioned simple ring seems griod. 

The form at / is that of B reversed, that is, the small square ring 
is placed on the inside of the L-shaperi ring, and has, in addition, a 
horizontal step joint, while the outer member has a vertical step joint. 
An entirely different prindpie is utilized in the form at J, the inner 
L-shaped member having a taper, and the outer thin but high mem- 
ber havini^ a con^eaponding taper to fit ag^unst it. The idea of the 


taper is that the spring of the two rings, slightly opposed, will work 
through this to hold both against the cyllmier walb. The outside 
of the inner ring is knurled to hold the outer one fham rotating. Both 
have diagonally cut slots. 

In the form shown at A', there are three parts, divided vertically, 
but in such a waj' that the top and bottom are really dependent upon 
the middle to hold them in place both vertically and horizontally. 
It is difficult to see greater merit in this form than of three plain rings. 
The form at L is somewhat like that at F, except that the inner full- 
height ring has a pair of projecting ridges in place of the single central 
slot. Each of the small half-width outer rings has a central slot, or 
groove, and end ridges to fit around this. Like F, this has the small 
outer rings pinned, but differing from it, all have diagonal slots. 

In the form seen at M, three parts are used, but the center full- 
height piece has its outer surface in the form of a double taper, upon 
each half of which one of the small half-height outer rings of triangular 
cross-section rests. In that shown at N, the ring is a continuous 
spiral, being somewhat similar to A in this respect. Its cut, however, 
is upon a slope all the way, so that its thickness varies continuously. 
It is made of heat-t reatrd steel. It is difficult to see how the vertical 


Piston and Ring Troubles and Repairs 

Removal and Replacement of Pistons. Speaking of pistons, 
there are several things that the beginner should leam about their 
removal and replacement. While it is not a dlflficult matter to puU 
a piston out of a c\'linder, when both have been previously lubricated, 
and all proper precautions taken to loosen connecting parts, there 
are a few important things to remember.. 

The piston should be drawn out as nearly parallel to the axis 
of the c>'linder as is possible, accompanied by a twisting motion not 
unlike taking out a screw, in case it sticks a little. If ttie piston 

sticks badly, pour in a little kerosene and work the piston in and out 
3o as to distribute the kerosene between the two surfaces. 

To get at the spaces the rings must be removed, and as they 
are of cast iron and very brittle, this is a delicate task. Two 
methfxls of accomplishing this are illustrated in Fig. 42. If the 
owner has a pair of ring-expanding pliers, the rings can easily be 
expanded enough to Hft them over the edge, as shown in (a). As 
very few owners possess this useful tool, however, a more common 
way is shown in (fc). Secure a number of thin, flat steeb aboi 



3 inch wide and ^ inch thick- — ^corsetsteels, flat springs, or hack-saw 
blades may be used, although the latter require more care on account 
of the teeth along one edge. The length of these steels should be 

such as to reach from about an inch below the last ring, to the top. 
Lift out one side of the ring with a small pointed tool and slip one 
of the steels between the ring and the piston, then move around 
about one-third of the waj' and insert another, taking care to hold 
the first in place; repeat the opera- 
tion with a third steel. When these 
are in place, the sleets will hold the 


one until it gives suddenly and is then spread beyond the resisting abil- 
ity of the iron. It is applicable to all forms of rings, except those with 
diagonal slots. In addition to the construction shown, it is de^rable 
to fit a spring which will draw the handles together when not in use. 
This closes the jaws and keeps them closed, ready for immediate use. 

An even better and more simple form, but without the safety feat- 
ure of that just mentioned, consists of a large diameter steel spring, 
shaped not unlike a very big piston ring, which has a pair of handles 
fitted to the ends. This is shown in Fig. 44, which indicates how 
the nubs on the two handles are shaped so as to take hold of stepped 
joint rings. By making these nubs differently, any form of ring can 
be handled. A device of this sort saves the repair man lots of time. 

Loosening Seized Pistons. When the pistons and rings freeze 
into the cylinder, or seize because of a lack of lubricant, there is 
nothing quite so good nor quite so quick acting as kerosene. The 
cylinder head should be opened as quickly as possible, and the 
kerosene poured in liberally on top of the pistons. This should be 
done in each cylinder. Kerosene is thin and will work down between 
cylinder wall and piston rings, gradually cut- 
ting away the two where they have frozen 
together. If kerosene is not available, take 
the thinnest lubricant at hand; heat it so that 
it will be still thinner and more penetrating. 

FW. 4fi. Bmpk Polon-I^ PulHni Outfit F1>. M. Pirton Riu Fuller 

Vbirb AUon lor eS. of Pin 

then pour it in. At times, olive oil can he combined with kerosene 
to advantage. 

Freeing Wrist Pins and Bushli^s. When the piston pin or 
wrist pin is inserted directly in the piston, it is usually a light fit, 
80 tight, sometimes, that the repair man experiences difficulty in 
gettii^ it out. To overcome this difficulty, a piston pin puller is 



needed. One of these, shown in Fiff. 45, is made from a piece of steel, 
a steel strap, and a large cap-screw. This piece of steel is drilled and 
tapped for the cap screw, and for the bolts to hold the steel strap. 
Then the latter is fastened so as to be about I inch larger in diameter 
than the piston, or still larger if a long cap screw is available. When a 
pin is to be removed, the strap is put around the piston and the cap 
screw screwed in until it bears against the end of the pin. This can 
be done by hand. Then a wrench is applied, and as the screw is 
forced in, the pin is forced out on the opposite side. Be careful to see 
that the far side of the steel band is below the piston pin hole, so the 
pin will be able to come out without touching it. 

This can be simplified b^ haMng an entlless steel band with a 
nut on the mside of it to form a bacJting for the cap screw to work 
against, or, the steel band can 
he welded to the nut. 

A form which removes 
the above difficulty is that 
shown m Fig, 46, This is 
made so that it holds around 
the piston at two points, 
jibo\e and below the piston 



this t\'pe is that the nut shown on the right, which is operated to 
force the bushing out, must rest against the surface of the piston 
while being turned around. If a small U-bar be made to rest against 
the piston side, with a central drilled bole through which>the threaded 
end passes, the nut will bear against the outside surface of this, so 
that even if the nut should scratch, no harm will be done to the piston. 
These pullers are used as substitutes for nn arbor press, but this is 
desirable, as the use of the press is likely to distort the more or less 
delicate piston. With aluminum and the lighter weight cast-iroa 
pistons, this is a thing which it is desirable to avoid. 

Some motors have the wrist pin locked in place by means of an 
expanding nut with a sunken square hole for turning. To start these, 
a vTench with a square projection or tit to fit this is needed. Such 
a ATench is used on certain lathe chucks, so one can alwa>'s be bor- 
rowed in a machine shop or tool room. 

Mandrel for Tumii^ Pins. Because of its being hollow in 
many cases, the wrist pin is difficult to handle when any work must 
be done upon it. For this 
purpose, a mandrel is needed. 
The method of constructing 
and using this is shown in 
Fig. 48. This consists of a 
shaft with a taper at one 
end and thread at the other, 
for a tapered nut. The wrist 
pin is slipped on the outer 
end, the taper nut put in 
place against it, and the 
backing nut put on behind that. Then these are screwed up until 
the two tapers hold the pin firmly, after which it may be placed in 
the latbe and work done upon it. 

Speeding Up Old Engines by Lightening Pistons, Etc As has 
been pointed out previously under "Cams", one way to speed up an 
old engine is to replace the old camshaft and cams with new ones 
giving more mfxlem timing. Another and a less expensive and 
troublesome way in which this can be done is by lightening the 
pistons and the reciprocating parts. This the repair man will surely 
be called upon to do, as the manufacturer probably would refuse 



In order to get out any amount of metal worth the trouble, it 
will be necessary to drill from 12 to 20 or more holes of from J-inch up 
to 1-inch diameter, depending ujjon the size of the piston as to bore 
and length. In a sbc-cy tinder motor, i 
thif> amounts to almost 100 holes 
(e\en more in some cases), and as 
these must be drilled with consid- | 
trable similarity in thepisttjns, itis 
ttcU wortli while to construct a fix- 
ture to aid or speed up this work. 

One idea of the way such a 
lightened piston should look when 
finished is given in Fig. 49, which 
shows the steel pistons used in the I 
Sunbeam racers. These are made i 
this way to give the maximum qf 
lightness with strength. Although 
made from steel, this is done 
.simply to get very light side 
i, and the general appear- 
ance of the skirt with its 


very well. To one of the uprights is pivoted a long handle, having 
a lined V which matches with that of the upright helow it, and ^ves 
a good grip on the piston. 

Drilling Holes. When drilling to save weight, the holes are 
put in close together and in regular form, the idea being to take out 
as much weight of metal as is safe. In doing this, it is well to work 
out a scheme of drilling in advance, to make a heavy brown paper 
template, and fasten this to each piston in turn. It is-not advisable 
to remove all the metal possible at first, but only enough to show the 
benefit of the method; after it has proved satisfactory, the first job 
may be improved upon later. For instance, In lightening pistons, 
it is a good plan to use a j-inch drill the first time, and not to put in 
too many holes. If this proves satisfactory, and the owner comes 
back for more, you can go over the same lot of pistons, using a i-lnch 
or f-inch drill between the existing holes, and thus reduce the weight 
of the lower end of the piston to its lowest possible point. 

Testing Size of New Piston. A skilled repair man gives the 
following suggestion relative to trying new pistons for clearance: 
When not certain whether the new piston will give sufficient clearance, 
heat it to about 600° F. If it is a snug fit in the cylinder, it probabh- 
will give satisfaction under normal running conditions. This, of 
course, is only approximate as the cylinder would heat up in use and 
expand but it serves the purpose and is quickly and easily done. 

Non-Leaking Rings. Another repair man says that when the 
rings get old, they can be made compression proof by grindjng down 
so that two old ones will occupy the space formerly taken by one. 
This would work well for the top groove with a new ring lower down. 

Sometimes a ring will get broken when no others, either old or 
new, are obtainable. In such a case, the ring can be welded, if unusual 
care is exercised not to melt away any of the metal. 

When rings must be turned in the lathe, either for reilucing the 
thickness or for truing up the face, a wooden face plate should be made 
with a slightly tapered groove for the ring to fit into. The ring 
should be pressed into the groove, and its natural spring will hold it in 
place. When working on the outer diameter, the face of the wood 
will have to be cut away sufficiently to allow the ring to project, or, 
instead of a angle large central hole, an annular ring can be turned in 
the wooden face plate, the ring being fitted over the outside of it. 


Tracing a Ring Knock. Many times there is an elusive light 
- knocltiiig or cliattering in the motor, especially at low speeds, which 
cannot be run down. This is often due to piston rings wearing at the 
top and bottom so they are loose in their grooves. When the piston 
moves upward, these rings remain stationary until they- strike the 
bottoms of their grooves; when it moves downward, the rings strike 
the tops of the grooves. At low speeds, these noises can be distinctly 
heard; but at higher speeds, they are so fftint that they blend off into 
the general murmur of the engine. Another noise, which comes from 
the rings, is that due to weakness or loss of spring. This is shown by 
a sharp rapping somewhat like a piston slap, when the throttle is 
opened suddenly. If the rings, and especially the top ring, are not 
stiff enough to resist the compression and explosion, this force will 
compress them. At the end of the stroke, 
they will expand suddenly against the 
cylinder wall, causing the rapping 
described, A notch filed in one edge so 
the pressure can leak in behind the ring 
will help matters, although new rings are 

Curing Excessive Lubrication. Uolc! 



removes the oil from the cylinder walb into the groove* whence it 
passes through the holes to the piston interior and there drops back 
into the crankcase. No ring is placed in the slot as it would prevent 
the free passage of the oil. Thisdevicestops the smoking immediately. 

Loose Piabms. Many times the pistons will wear just enough so 
that they are loose in the cylinder all the way around. This causes 
leakage of gas, piston slaps, and other similar troubles. If the owner 
of the car does not care to buy new pistons, or if the car is an 
"orphan", or if, for other reasons, pistons cannot be obtained, the 
clever repair man can remedy the trouble at small expense. The 
process consists in heating and expanding the old pistons. The 
heating is done in charcoal and must he done very carefully and 
slowly. After the pistons become red hot the fire is allowed to go out 
slowly, so that the piston is 
cooled in its charcoal bed. 
Sometimes as much as n^ 
of an inch can be gained in 
this way. WTien the pistons 
are so far gone that they 
cannot be handled in this 
way, they must be replaced 
With new ones. 

Mounting Pistons on Lathes. It is difficult to handle a piston 
in the lathe, or machine the outside in any manner, as a chuck does 
not get enough of a hold on it, and is likely to mark the surface. 
\Vben work on it is necessarj-, the piston can be handled effectively 
by using a small rod with an eye at one end. This is made to fit the 
piston pin in the case of an old piston. The rod is run through the 
hollow spindle and bolted at the outer end. The tightening of the nut 
on it pulls the piston up against the face plate as Fig. 52 shows. 
This same method can be used when making a new piston. In the 
latter case, it is held in the chuck to finish the outside and inside, then 
the wrist-pin hole is drilled, bored, and reamed, and the wrist pinfitted. 
Finally, the finishing cut, or grinding of the outside, is completed. 


Des%a Oiaiacteiisttes. IlSedion Form. Established prac- 
tice in Qonnecling-rod design is almost alt in favor of the ^qjmon 


H-section rod, usually with two bolts to attach the cap. In some 
cases four bolts are used, since with four bolts a flaw or crack in one 
is less likely to cause damage than is the case when only two are use<I. 
The old scheme of hinging the cap at one side is now practically 
obsolete, having been discarded because it made accurate adjustment 
of the bearing surfaces almost impossible. 

Tendency to Lighten Rods. The modern tendency toward 
light<?ning the weight has extended tn the connecting rods, since a 
portion of the rod is considered as reciprocating. This lightening 
has been accomplished by 
external machining. Thus, 
in the tvpical connecting r*)d 
of forged alloy steel, shown in 
Fig. 53, the format the left is 
thatformerlyused, while that 
at the right is its present 
shape. Note how the round- 
ing sides of the H-part, nec- 
essary in forging, have been 
machined off; how the fillets 
at big end and piston enil 


llie question of cost, bowever, is a consideration, since it is necessary 
to bore the hole through the inside of the rod, whereas a forged rod 
of H-sectiou requires no machining except at the end. 

The wonderful progress in welding, however, has made it possible 
to construct a tubular connecting rod at a very low expense, and, owing 
to its many advantages, this is finding much favor for small motors. 
The two ends are machined and a section of tubing welded to them. 

One advantage of the tubular rod, in addition to its superiority 
for withstanding the compression load to which a rod is chiefly sub- 

ject, is that it can be used as a pipe to convey oil from the big end 
to the piston-pin bearing. 

Fig. 54 shows an example of a very light-weight, high-quality, 
aviation-motor connecting rod, machined out of a solid bar of 
alloy steel, and provided with four bolts in the cap. 

Connectii^Rod Bearings. Usual Types. Connecting rods have 
two different forms of bearings. This is due to the difference in ^eir 
service. At the upper or piston end, the bearing is usually a high- 
grade bronze tubing, machined all over and pressed in place. When 
in place, it generally has a central oil hole drilled through rod and 
bushing, and then a couple of oil grooves are scraped in by hand to 
start from this hole and distribute the oU outward in both directions 
on its inner surface. 



At the lower or, as it is usually calletl, big end, the connecting rod 
must liave a better bearing. This end is bolted around the crankshaft 
pin and must sustain high rubbing speed, as well as the load of explo 
sions. Bolting it on, and the need for removing it occasionally, call 
for a form which is split horizontally. Generally, this bearing is ot 
high-grafle bronze with a softer, or babbitt, central lining which can 
be replaced easily and quickly. The lianler Itrorine back will sustain 



somewhat, in that there are two connecting-rod big ends working 
upon one crank pin, that is, an eight-cylinder V-engine uses a four- 
cylinder form of crankshaft with two connecting rods on each pin. 
This modifies what was good connecting rod bearing practice, one of 
two different forms being utilized. When the rods are placed side by 
side with individual bearings, the pins are made very large and as long 
as possible, in order to give adequate bearing surface. The other 
form is the forked rod in which one rod works within a slot in the 
other. In this t>T>e, a split bearing of the usual form is placed in the 
forked or long rod, and the outer surface of the central part of this 
prepared as a pin surface for the other or central rod. The requisite 
area of the smaller rod bearing is made up by its larger diameter. 
This is well shown in Fig. 55, where the rods and bearing are shown 
assembled, and the separate big-end bearing is shown at the rig^t. 
In another type of V-motor connecting-rod bearing, the larger bearing 
is slotted for the central rod and its bearing, the slot being made large 
enough to permit a rotation, which never exceeds a quarter of a turn. 
This arrangement is more complicated to install and repair than the 
form shown. 

Connecting Rod Troubles and Repairs 

Qassification of Troubles. In general, all connecting-rod 
troubles come under one of four headings: straight rod, proper bear- 
ing adjustment, mechanical work (scraping bearings, straightening rod, 
or other work), and special equipment for doing connecting-rod work. 

Stra^htening Bent Rod. The need for a straight and true 
rod is apparent, but it is surprising how many rods are not straight, 
particularly in old motors. 

Many erratic and bad- 
sounding motors, have all 
their trouble caused by a 
bent rod. A connecting 
rod can be bent either of 
two ways, and one gives as much trouble as the other. If bent in 
the plane of rotation, the rod will simply be shortened, the piston will 
not go as high as it should, and it will go down a little lower than 
nminal. Moreover, the bend will press it with imusual force on the 
cylinder wall on one side and cause it to wear more than the other. 

i?/-/ // FressBedl'^ 





Fig. 56. Method of Teeting Connecting Rods 
with Two Mandrels 


The combination will soon result in trouble. When bent in a longi- 
tudinal direction, that is, fore and aft, the upper end of the rod will 
run against one side of the piston or perhaps only knock against it 
on each stroke. At any rate, this too, wiU give trouble. 

Methods of Testing Straigkttuss qf Rods. The first thing to do 
when a connecting rod is suspected is to take it out and test it. One 
way of doing this is to attach the lower end to a mandrel, which 
can be bolted into a drill-press table, as shown in Fig, 56. Before 
doing this, the small end is also fitted with a mandrel, the lower part 
of which is of considerable length and has two short vertical pegs. 
When the big end is bolted down, if both the small pegs on the other 
end touch. It proves at least that the two holes (big end and small 
end) are parallel. If one of these pegs is off the table as shown. 



Fig. 58. Coimectinc; - Rod ^tnu^tener Cotwtmeited 
from Threc^uArtcT-lDch Bar Stock 

is that it always works the same, while the use of surface gages 

and calipers varies from one workman to another, and even with the 

same man, from day to day, according to his moods and feelings. 

As the sketch shows, there is a mandrel for each end of the rod, that 

for the big end bang jMvoted in the fixture. AMien the rod is forced 

into this, and the other 

mandrel put in place in the 

pistcm end, if rotated down 

to a flat position (as shown), 

the small end mandrel 

should touch both of the 

fixture stops. If badly 

twisted, it will not be able 

to go down on one side. 

Straighiening Jigs. 
When it has been proved 
that the rod is not straight, it is necessary- to have a device for apfJy- 
Ing pressure in order to straighten it. The simplest way is an ordinary' 
straightening press consisting of a pair of ways ^ith V-blocks upon 
which the work is supported and a lever or screw to apply the pressure 
in the middle. The work is supported on the V-blocks, the distance 
apart var^Tng with the amount it is to be bent — far apart for a 
big bend, dose tc^;ether 
for a small one. For as 
short a member as a con- 
necting rod, howe\'er, 
this is not sufficiently 
accurate, and be»des,the 
f onn of the rod does not 
suit it to good results by 
this method. 

A mofie fixture for 
bending a rod, diown in 
Fig. 58, consists of a pair of hooks for holding it and a central 
screw for applying power. The rod is slid into place inside the 
hocdcB and the screw turned imtil the rod is straightened. Then to 
la r i 'gnt its qjfinging back when the pressure is released, it is peened 
oo the side cqiposite the screw. Hie advantage of this method is 

Fig. SO. Box Type of ConueKrting-Kod tHnicfateoer 


.\vs\ vv.'. \'.k'. ,' , ,v. 

that it throws all stresses upon the nxi itself and none on the bear- 
ing surfaces. The hooks are forged from high-carbon steel of f-inch 
square section. Tlie screw should be not 
less than f inch to f inch in diameter and 
fine threaded. 

Another fixture is on the box order, 
shown in Fig. 59. This has a pair of end 
clips which hold the rod tight by means of 
wedges wliich are driven into place. When 
this has been done, the rod is straightened 
by means of the central screw. As will be 
noted, the principal difTerence between the 
two forms. Figs. .58 and 59, is in the holding 
method. There are other forms, as well as 
forms of mandrels for lapping in big-ead 
bearings, which are so constructed as to give 
a check on straightness and to allow of 
remedying the situation if the rod is not 
straight. Some of these will be described. 
Offsetting Causes Trouble. Many motors 
^ built with offset connecting rods, that 



a rcx^ing motion of the pins results, and this causes a noise. New 
bearings help tanporarily, but a stiffer connecting rod will often 
roned y it more or less permanently. 

Adjustment of Connecting-Rod Bearings. Babbitting Bearings. 
As has been stated, the majority of connecting-rod and crankshaft 
bearings are bronze shells or backs, lined or faced with babbitt as a 
wearing metal. The bronze provides the stiffness and long life, the 
babbitt, the softer wearing face which is easily and cheaply replaced. 
In this replacement, a form or jig to simulate the crankpin and 
approximate its size must be used for a center. A form made of 
wood is shown in Fig. 61. This is simply a round member of hard 
wood, turned up slightly smaller than the actual crankpin at the 
upper end, while the lower end is left large to form an under surface 
for the metal. Next, the upper part is split or rather has a cut taken 
across it, equal in thickness to the shim to be used when the bearing is 

Fig. 62. Home-Made Creeper 

assembled in place. Then, when the babbitt is poured in, a metal 
member is set across the rod to form the shim, which is shown in the 
smaller sketch at the right. 

This method has the advantage over that of using the pin when 
pouring the metal in position, because it gives a Uttle surplus to 
machine off, and thus makes the surface more accurate before it is 
scraped. If broaching to harden the surface of the metal is resorted 
to, it gives a little metal to broach down. Moreover, by making it 
so simple and easy to handle, the work of babbitting is made easy. 
TTiis cannot be said of tr>-ing to babbitt in place. The core need not 
necessarily be of wood; it can be of metal or of an\^hing else desired. 
But the wood has the advantage of being easily worked, or of being 
dieap and quiddy obtained. 

Kinks in Adjusting Bearings, L^sually, crankshaft and connect- 
ingH!od bearing adjustment is a difficult job. This is particularly 


true when the engine is not removed from the chassis. The con- 
necting-rod bolts are tight and hard to reach, and the operator, who 
is lying on his back, has all dislodged dirt or oil dropping in his face. 
Work like this calls for an easy means of getting under the engine and 
out again. For this, a form of creeper is necessary. There are many 
forms made and sold, but a simple one which any repair man can 
construct for himself is shown in Fig, 62. This consists of a wood 
frame with casters at the four corners and longitudinal slats for the 
floor. By making tJie ends concave, the surface is made concave. 
With a pillow or other head rest, it is more comfortable to use. 
Another way in which this work may be facilitated is to make a 
special socket wrench for connecting-rod nuts and to make it deep 
enough to hold four nuts, one 
JJjiiJft over the other. Then with a 

spring-stop arrangement, Fig. 63, 
the nuts from two rods can be 
taken off without stopping; or if 
lock nuts are used, the nuts and 
lock nuts may be removed from 



wear, and .003 inch for severe wear. If more than this has been 

worn off the bearings, they need re-scraping, as this is about the 

. maximum that can be taken out without scraping. Usually, when 

the bearings have been taken up in this way, the caps are put back 
on pretty tight, a little bit tighter than they were previously. Then 
they are flooded with oil and run in this condition. The combina- 
tion of excess oil and tight 
caps soon gives the entire bear- 
ing surface a fine polish which 
will last for many miles. 

Special Sleeve Replaces 
Shims. In one motor (Reo), 
the shim is replaced by an 
ingenious arrangement of a 
threaded sleeve around the 
bearing bolts. This b shown 
in Fig. 64 in which the sleeves 
are marked A and the bolts 
B. It will be noted that the 
sleeves rest against the upper part of the bearing and have a head 
against which the bolts rest, so that the latter can be tightened only 
aa far as the sleeves allow. With this construction, when it is desired 
to tighten a bearing, the socket wrench is slid on so as to hold the 
heads of both bolt and sleeve, and then turned to unscrew both. 


Then the socket is drawn off the sleeve head, in the position shown 
at the left, and the bolt sen-wed back to pinch the bearing together 
and lock it. As will be noted, the two halves of the bearing metal 
are separated a considerable distance so that this arrangement is 
good for many thousand miles. Two years" running will usually 
exhaust the possibilities of the original bearing and its shims, which 
calls for re-babbitting, re-scraping, new shims, or for an entirely new 
bearing. This form of construction could be used anywhere that 
the bearings are likely to need frequent readjustment. 

Mandrel for Lapping. In order to give the connect ing-ro< I 
bearings the best possible surface, a mandrel should be used to lap 
tliem in. This is the equivalent of running in. The rod, with bear- 
ings in place, is put on the mandrel, and the bolts tightened a little; 
then it is worked back and forth, until the flattening down of the 
surface will allow more tightening of the bolts. This is continued 
until, with a mandrel the exact size of the erankpins, the bolts can 
be pulled up dead tiglu. Then the rod is removed ; it is finished. 
Such a mandrel, shown in Fig. 65, is usually a piece of steel turned up 
on one end to the exact size of the crankpin. with a flat spot machined 
in the other end to allow holding in the vice. By making it perfectly 
straight, a try sriuarc against the mandrel will show the correctness 



Variation of Design, llie 
greatest variations in auto- 
mobile crankshaft design, aside 
from those pennitted or made 
necessarj' by diflFerences in the 
quality of material, are due 
to the conditions involved in 
the different combinations of 
cylinders that can be utilized. 
Thus the number of crank 
throws, as well as their posi- 
tion, varies with the type of 

As the repair man knows 
crankshafts today, they are of 
two kinds. The first is the 
four-cvlinder form, in which 
all throws are in a single plane. 
This t^-pe of shaft has four 
pins, one for each connecting- 
rod big-end bearing. It may 
have either three bearings, as 
shown in Fig. 66,' or five bear- 
ings. The second t>T>e, which 
the repair man is likely to 
meet, is the six-cylinder shaft, 
which will have six pins for 
connecting rods; these are 
grouped in pairs, and each pair 


m a different plane, the angle 
between them being 120 de- 
grees. This tj-pe of shaft may 
have either four or seven bear- 
ings. In the four-bearing 
form, there is a bearing at each 
end, and another between each 
pair of cylinders, as shown in 
Fig. 67, with pistons and con- 











• o 




Meeting rods attached. In the seven-bearing form, there is a bearinfC 
on each side of eaeh connecting rod. These are the modem types, 
hut older shafts miiy be encountered occasionally, in the way of 
four-cylinder shafts with two bearings, one at each end only; also with 


C.,<iH,>y •<! .\','.li,tr A .Woi-mon Company, /nrfiaiupoii., IniiaHa 

four hearings, the latter having the usuaUenter bearing eliminated. 
Tlie modern tendency is towani siniitUHciitioii, compactness, and low- 
ered first cost; and the shafts with the fewer number of bearings are 
on the increase. 


Eight-Q'linder engines generally use a four-cylinder form of shaft, 
with two connecting rods on each of the four pins. This is explained 
previously under connecting rods. Similarly, twelve-cj-linder motors 
have a typical six-cylinder crankshaft, with two rods on each of the 
six pins. 

Balanced Crankshafts. While not an assembled shaft in the 
sense just referred to, the balanced form is meeting with great favor, 
and is being widely adopted. This will be met by the repair man 
in two forms. One is like Fig. 66, except that the weights are 
machined to fit on the crank cheeks and bolted there. The repair 
man should not remove these unless it is absolutely necessary, as 
they vary in size and weight. They are fitted in place with extreme 
care and fastened extremely well. The other type — the kind being 
introduced into the latest models — has its counterweights forged as a 
part of the crankshaft. Fig. 68. In this type, the weights are adjusted 
to make the proper balance when the shaft is being machined. 

Oankshaft Bearings. The bearings of the crankshaft in the 
crankcase do not differ materially from the connecting-rod bearings 
just shown and described. They may be a little longer, but the type 
is the same. They are pinned orotherwisefastened in the crankcase so 
83 not to rotate, while the connecting-rod bearings are fastened in the 
connecting rods so as to rotate with them. A few shafts will be met 
which have ball or roller bearings, but the great majority have the split 
bronze-backed, babbitt-faced bearing described for connecting rods. 

Crankshaft and Connecting-Rod Bearing Shims. Practically all 
split or two-piece bearings for either crankshafts or connecting rods 
are assembled in place with shims. These are very thin flat pieces 
of metal set between the two halves of the bearing when it is 
assembled new to spread it apart. The shaft bearings are scraped to 
an exact fit on the pins with these shims or expanders in place. Then 
when wear occiu? in the bearing, so that its inside diameter is enlarged, 
the bolts may be taken out, a shim or shims of the required thickness 
removed, and the bolts put back and tightened. This removal 
reduces the diameter of the inside of the bearing. To facilitate this 
action, the shims are generally put in, in such a way as to allow taking 
out a number of thousandths of an inch, there being two shims of 
rAr, two or more of nftnr, possibly one of nftnr, and a thicker one, or 
more of the very thin ones. These shims enable the taking-up of wear 


amounting to lo'oo of an inch, when one of the thinnest shims is 
removed; tAt by removing one of that thickness; m'aa by removing 
a TTsW and a tAu; iTAnF by taking two 2's, etc. 

Of course, a crankshaft bearing or a connecting rod-bearing will 
not wear entirely round, but the work of adjusting either bearing is 
reduced to a minimum by the use of shims. When the wear is verj" 
bad, the bearings should be re-fitted and the shims left out. 

An entirely new form is the laminated shim. The total thickness 
required b built up of very thin laminations, either one or two 
thousandths of an inch thick, so that in adjusting a bearing as many 
laminations are peeled off as are necessary to take up the wear, thai 
the original shim, slightly lessened in thickness is rephtced. 

In Fig. 66, the end view shows both connecting-rod and crank- 
shaft bearing shims in place, and indicates how they perform their 
function of holding the halves of the bearing apart when the bearing 
is being fitted. 

Crankshaft and Bearing Troubles, and Remedies 

Bearings. Bearings of the two-piece, or split, type pve the. 
auto repair man fully as much trouble as anything, in fact, the 
crankshaft bearings should not be tackled until considerable repair 
experience has been had. In general, wear on the bearings is due 
to one of two causes: either to a soft metal which has caused vertical 
wear on the inside or outside of the lower half of the bushing, or to a 
vibrating shaft which has worn an oval hole somewhere in the length 


vill not fit the boles in the case; or 
possibly the wear may have com- 
municated itself to the case, so 
that the hole there is out of true. 
If this be slight, refilling the cases 
with babbitt metal or building-up 
may be resorted to, but if tlie wear 
is considerable, a new set of bear- 
ings is the only remedy. In build- 
ing up the bearing, strips of aoft 
metal are placed in the worn spots, 
after cutting or filing them to fit 
as closely as possible, and the bear- 
ing driven down upon them as firmly 
as possible. In this way, it is often 
possible to build up a worn crank- 
case to answer for many thousand 
more miles running. 

Bearing Wear. In this connec- 
tion, it is important to know how 
and why bearings wear. Normally, 
between the crankshaft bearing and 
the pin, there is a space of perhaps 
.002 inch divided into .001 inch all 
around, and this space is occupied 
by a fihn of lubricant. So long as 
this is the case, if the metal remains 
hard and does not give under the 
constant pounding, and the film of 
lubricant stays unbroken, it remains 
a perfect hearing. But the film does 
get broken or reduced, and the softer 
metal does give, so we have a con- 
dition shown at A, Fig. 69. Instead 
of a cylindrical pin centered in a 
cytiodrical hole, one or the other is 
worn oval. This is usually the 
bearing, for the weight of the 



shaft, coupled with the pressure on it, keeps it at the bottom of 
the hole. The tendency, then, is to increase this eccentricity. 
In this condition, the pin is running against the bearing metal at 
only one very limited surface, so all the pressure and all the wear are 
concentrated there. If tlie bearing is hard, or if a hard spot develops, 
the pin is likely to wear flat on the bottom side, as shown at B. When 
the bearing is fitted to the case, great care and accuracy are required, 
I£ care is not taken, an incorrect fitting, shown at C, results. Here 
the shim does not entirely fill the opening for it, and the bearing metal 
rests on the case at one point; on the shim at another; and does not 
touch either at a third. This is remedied by scraping both bearing 
and case, as shown at 73, or the shim alone as seen at £. In the former 
it will be noted how the full shim has raised the bearing so that its 
points project into the pin, 
where scraping will be needed. 
In the latter case, also, scrap- 
ing the bottom of the bearing 
will be necessarj', for using a 
y fitted shim has raised the 



this: If the rod is placed vertical, it will stay there, but if pulled 
over past 20 decrees from a vertical, it vill swing down, of itself, 
to the bottom position and stop there 
widiout continuing to swing. If it 
will do this, it is just tight enough . If 
it will not swing down at all or con- 
tinues swinging, it is either too tight 
or too loose. To a certain extent, 
crankshaft bearings are delicate, and 
they can be mined by having the 
big ends too tight. 

Holder for Bearing Caps. When 
a number of bearing caps have to be 
scraped, or filed down, it is worth 
while to make a holder for them. A 
plain form is shown in Fig. 70. This 
consists of a semicircular piece of 
metal which fits into the hollow part 
of the bearing, with each end pivoted pj^ , 
on two L-shaped members. Themem- — .>««™m.,u>. 

bers are held tightly in the vise, and the tighter they are gripped the 
tighter the bearing cap is held. This jig holds the cap with the desired 


8eiiii-8<Hket Wreneb lot Cnuk- 

fit, 73. 8at-Up tat Suppoctina Cnnlnlwfta O' 

firmness, yet it leaves the whole upper surface free and clear so the 
workman can work at it readily and do a neat quick job of iiw.%. 


The same layout is suitable for connecting-rod caps, except where they 
have an oil scoop or other central projection which interferes. 

Another Handy Wrench, The form of the crankshaft-bearing 
cap and also of the connecting-rod bearing cap are such that no space 
is wasted. Very often the nut is so close to the cap that it is difficult 
to turn, unless the cap is taken out of the motor where the wrench can 
be applied at right angles. The use of the socket form of wTench, 



the form made of tubing, and has part of one side of the socket cut 
away. Tbb makes its quick application to the nuts easy, although 
it also limits the amount of turn possible. Generally the case nuts 
are different in size from the connecting-rod nuts; so it is advisable to 
make the wrench double ended with a size at one end for the rods, 
and one at the other end for the case. 

Holding the Crankshaft. When the shaft has been removed from 
the engine, and work is to be done upon it, it is an awkward thing to 
handle. It is just delicate enough so that it cannot be handled care- 
lessly, yet its size and weight make it difficult to move around. 
Hius, in lapping the shaft pins, in fitting connecting-rod bearings, or 
doing other work upon it, a sup- 
pMt which is »mple, easily moved 
utiond, yet adequate, is needed. 
Ordinarily a shaft is clamped in a 
viae, but this is not always satis- 
fiwtory when working on an end 
bearing. The method shown in 
fig. 72 has many advantages. 
llus consists of a special bench 
fixture and a notched board. The 
latter should be at least 1-inch 
stodc, that is, it should be J-inch 
when dressed on both sides. The 
forma: is simply a metal angle with 
a series of radial slots to take the 
fiywheel bolts, with a central hole 
for the shaft to rest in. The metal above the hole is well cut 
away to facilitate putting the shaft in and taking it out. 

HandUif Shaft in Machines. When the crankshaft is to be 
machined, no matter what the form of lathe, grinder, or other machine, 
the fart that the pins are eccentric necessitates a special dog or jig 
for holding it. If an ordinary flange is bolted on the end, the main 
pins can be turned, smoothed down, or ground, but the crankpins 
cannot. What these latter need is a form of flange or plate with two 
exact centers on either side of the central one at distances exactly 
equal to the CTank throw. One is shown in Fig. 73, which is attached 
to a four-cylinder shaft all ready for the machine. Above w\^ \i« 



seen another shaft witliout machining flanges. The bolts which 
attach the flanges to the shaft can be seen beyond the right-hand 
flange and at the far end. The rack in the background, on which 
these shafts are placed, is of interest also, forming, as it does, a simple 
and efficient means of holding the shafts, jet it is convertible for 
holding other parts or units. It is simply a stout form of horse. 
rather high, and with three legs instead of the usual two. The braces 
are all put on the inside to leave the surface clear, while the support- 
ing pins differ only in length. In this case they have been made 


ig Fiiture ol Sinjple Cowtni 

Adjustable Crankshaft Flanges. In the small shop the general 
run of work varies 30 much that the principal difficulty lies in having 
flanges, dogs, or fixtures for handling the variety of crankshafts that 
come in. Diameters vary 30 much that a wide range of central holes 
is needed, because throws 
are all different. This 
gives a different center 
to center distance; then, 
too, there are still one- 
and two-throw, and 
other old forms of shafts 
in use, which come in 

occasionally for repairs. For these reasons, it is not wise for the small 
shop to go too far into special crankshaft fixtures; it should stick to 
simple dogs, with adjustable center distances, like the three shown in 
Fig. 75. While the shaft indicated is a single-cylinder form, dogs of this 
tj-pe can be used on other forms. This constitutes their biggest advan- 
tage. The variation in the three is self-explanatory to any machinist. 

Crankshaft Lapping. The pins of a crankshaft need lapping 
the same as other pins where a grinding machine is not available. 
There are two ways of doing this: by hand, which is slower but more 
simple so far as apparatus is concerned; and by machine, which 
requires special fittings for this purpose. In the sketch, Fig. 76, a 
form of hand tapper is shown. This consists of a pair of hinged 
members, with a central 
hole lai^ enough to 
take various sizes of 
bushings, such as would 
be required on different 
shafts. A long handle 
is provided ; also a bolt 
to hold the two halves 
together when the bush- 
ing has been inserted. 
The babbitt bushing must be split and have end flanges to hpid 
the halves In place sideways. The handle gives leverage for work- 
ing the tool, which is made effective by the application of fine emery 
and oil on the pins to be lapped. In the same way, the pins are pol- 

Flg. 77. Lathe S«t-Up 

r Lapping Crankshaft Piu 


ished by means of a pair of long wooden clamps, shown below, and 
made in somewhat the same way. There is a hinge at the back; and 
the abrasive used is fine emery cloth, which is flooded with oil. 

The throws on the crankshaft can be lapped in the lathe by 

putting it between centers for tlie main bearings and by us'iiig a 
special flange for the other pins. A method which can be used is 
shown in Fig. 77. This consists of a special fixture, made from a 
large casting with a base to fasten to the face plate; a long extension 
arm, having a split end for attaching and detaching, to encircle the 
throw to be lapped. When this is used, the shaft is supported in 
V-blocks, somewhat flexibly it is true, but sufficiently. 

Welding Shafts and Cases. The welding of broken crankshafts 
and crankcascs, such as central breaks, breaks around the cylinder 
supporting surface, bearing supports, and supporting arms will be 
found fully discussed under the subject of welding, with full direc- 
tions as to the preparation of the work, the materials, and other details. 

Function of Crankcase. The lower part of the motor car, truck, 
or tractor engine is generally enclosed for the purpose of assisting the 


A section through a modern crankcsse is shown in Fig. 78, whidi 
illustrates a twelve-cylinder motor. Note the inclined upper sur- 
faces of the upper half to which the cylinders are bolted and the 
stiffening rib at the center line where the two halves meet. Note 
also how the lower half is simply an enclosure, carrying only the oil 
strainer (shown) and the oil pump (not shown). It has cooling fins cast 
on its lower surface to keep the temperature of the oil down. The 
shelf, which is cast on the upper half to close the space between the 

Fis. 78. Section tliroush Cnnkcan ol Box Type fm Twelve-Cylinder 
V-Type Pw:kud Motor 

sides of the crankcase and the chassis frame, serves the double purpose 
of a protecting pan to keep out road dirt and water and of a supporting 
shelf for accessories. Fig. 79 shows the same engine from the front. 

Crankcases are made mostly in two forms: the box type, which 
has more or less straight sides, with a fiat top and bottom; and the 
barrel type, wMch is round or a modified round with a fiat bottom and 
top. The one shown is of the box type; the barrel type is generally 
not split along the center line, but it has removable end plates which 
allow the insertion of the crankshaft and a very simple bottom plate 
which carries the oil supply. The one-piece type b supposed to give 
greater rigidity, but thb is at the expense of accessibility. 

Modem Tendencies in Design. There are two modem ten- 
dencies shaping toward a modification of, or the entire elimination (A, 


the lower lialf of the crankcase as it is now known. One is the mini- 
mizing of its functions, so it can be made of pressed steel, when it 
becomes a cover onl\-, and the oihng system is made such that the 
supply is carrieii elsewhere. The other is the casting of parts of 
the crankcase inteftrally with the cylinders. This has been done 
3uccessfull\- witli the Marmon. the Ford, and with others, in which the 
cylinder block and the upper half of the crankcase are cast as one. If 


crankcase, it is an all day's job to take out a piston and replace it. 
When the cylinders are separate, cast in pairs, or bolted on, a piston 
can be taken out and replaced in a couple of hours. 

Crankcase Materials. It is important that the repair man 
should know the materials of which both upper and lower halves of 
the crankcase and the gear cover are composed, for these may need 
repairing. In general, crankcases are of aluminum alloy, the exact 
composition varying. When this is the material, the gear cover is 
of aluminum alloy also. A few crankcases are made of cast iron, on 
very low priced cars. Others have the pressed-steel oil pan, pre- 
viously mentioned. A few high-grade cars have bronze crankcases; 
these are either government bronze or vanadium bronze. 

Crankcase Arms and Engine Supports. The engine is generally 
supported by crankcase arms extended from the sides or ends of the 
upper half of the crankcase and cast integrally. However, this is not 
always the case. In many unit power plants, the rear pair of sup- 
porting arms may be fixed to the fl^-wheel housing or to the transmis- 
sion case. Moreover, separate supporting members bolted or hinged 
in place may be used. These are heavy steel forgings, stout bronze 
castings, or heavy gage steel tubing. This may be done to allow 
the engine freedom of slight rotation and relieve it of twisting due to 
road inequalities; it may be done because of lack of confidence in the 
strength of the crankcase material as an- engine support; it may be 
done to facilitate foundry work on the crankcase, and thus reduce its 
cost; or for other reasons. In taking out an engine, the repair man 
should find out about this, as it may simplify or complicate the removal. 

Qear Cases, or Gear Covers. At the front end of the great 
majority of engines, the gears which determine the working of the 
engine and its accessories are placed. These may include the crank- 
shaft driving gear and any or all of the following driven gears : camshaft 
gear, magneto gear, water-pump gear, lighting-generator gear, oil- 
pump gear, and sometimes fan gear and air-pump gear. These may 
be driven directly by gear contact or by means of silent chains. In 
either case the gears are enclosed by a case or cover, variously called 
the gear case, gear cover, or cam-gear cover. This housing is generally 
of as simple a shape as possible, and is bolted in place with as few 
bolts as possible in the lower half of the crankcase, so as to facilitate 
its removal for crankshaft or other bearing inspection or for repair. 


Other details of the crankcase parts, not previously discussed, 
will be taken up under the groups in which they belong; for instance, 
camshafts and cams with valves and valve parts; lubricating parts, 
drilling in crankshafts for lubricating purposes, oil passages in the 
crankcase, etc., under lubrication; and others under their respective 

Crankcase Troubles and Remediet 

General Nature of Troubles. The most general crankcase 
trouble, aside from bearing trouble, is breakage. The usual bearing 
troubles previously outlined occur as well with main crankcase 
bearings. These require similar attention, and in their handling 
much special apparatus, such as stands, jigs, fixtures, and tools, can 
be developed by the ingenious repair man. Worn main bearings 
cause a knock. If this comes from any one bearing, it can usually 
be traced quickly. The use of the stethoscope is recommended tot 
any crankcase or gear-cover noises or troubles. A squeak from any 
part of the crankcase usually means a lack of oil or the rubbing ,of 
parts which should not rub. 

Mending Breaks. If the case is of aluminum, it should be 
watched carefully for breaks or cracks. If a crack develops, it should 
be drilled, plugged, and welded, as cyhnder water jackets. This iriU 


to vash wdl enough and long enough to Trmove all the acid. 
Moreovef, it should be kept from clothes or from any nood parts, as 
it is strong enough to attack fabrics end wood. 

The aluminum oil pan should be cleaned out at least once A 
season, for the strainer will separate a lot of dirt and dust, as well as 
otiier foreign matter, from the oil in the course of 8 or 9 months. 
This will be found in the bottom of the oil pump or beneath the oil 
proper, as a kind of slush or sludge. Sometimes it is thick enough 
to need stTaping, particularly in sandy country where the car gets 
little or no care. Generally, a kerosene bath will dean it out. This 
is followed by a "onceK>ver" with gasoline to clean off the kerosene 

and the last of the dirt. If any gasoline remains, it will evaporate 
and leave a crankcase which ' actually is clean. The porosity of 
aluminum emphames this need for a thorough cleaning, which is not 
needed so badly with pressed-steel oil pans. 

Machining Crankcases. Generally speaking, the repair man 
will not be called upon to do any machining on crankcases, beyond 
something like chipping or filing, or in the case of a break, patching 
or welding. But in case such a job should come along, it is important 
to know how to handle it, for there is no more important crankcase 
job than the machining of the main bearings. The necessity here 
is to keep them in perfect alignment, and this necessitates machin- 


ing all of them at once with a long boring bar, as shown in Fig. 80. 
The method of support upon the flat upper, or cylinder, face will be 
noted, also the holding down blocks bolted to the table of the machine, 
after being bolted to the cylinder studs. The provision for lubricant 
on each one of the boring cutters will be seen in the small copper pipes 
above and at the back. As the average shop does not have a boring 
tool of this kind, this work will have to be approximated. It could be 
done by hand, using the now well-known Martell aligning reamer, 
to ream the hearings out and put in new and larger bushings. This 
also has a series of cutters, much like the boring bar shown, and is 
actuated by hand. So the principal requisite would be a large flat 
surface on which to work. Possibly .this will be found at the drill- 
press platen, the planer table, or the working table of whatever large 
machine tool the shop possesses. In this job, the workmen should 
remember that unless the case is held firmly throughout, it is likely 
to give or spring, and this will spoil the whole job, no matter "how good 
it may be otherwise. 

In all orankcase repairs, the repair man should remember that 
the case is really the foundation of the engine, and if it is not firm 
of itself and firmly supported, the action of the engine cannot be 
positive nor continuous. Consequently the case should be handled 



Q. Into how many main groups can the mechanical parts of tlie 
car DC ciivKieGr 

A. Practically all motor cars can be di\nded into six general 
poups as follows: (1) engine, or power-producing, group; (2) clutch, 
or engine connecting and disconnecting, group; (3) transmission, or 
qpeed-var>dng, group; (4) final-drive group including rear wheels; 
(5) steering group for controlling the direction of the car and including 
front wheels and axle; (6) frame upon which all otiier groups except 
vheels are hung. The body makes a seventh group, but strictly 
speaking it is not mechanical. 

Q. How many sub-groups are there pertaining to the 

A. According to their functions, the parts and accessories of 
the engine may be subdivided into 10 groups: (1) cylinders, pistons, 
connecting rods, crankshaft, and other basic parts; (2) carburetion 
sub-group through which the mixture is supplied which enables the 
engine to run; (3) valve group through which the mixture is allowed 
to enter and leave the cylinders at the correct time; (4) exhausting 
system through which the burned gases are led away from the motor; 
(5) ignition system by means of which the mLxture in the cylinders is 
ignited at the proper time; (6) cooling system by means of which the 
tem[>erature of the motor is kept down to a point at which it can 
operate safely and continuously; (7) lubrication sub-group by means 
of which the rotating, or rubbing, parts are kept lubricated so as to 
run without friction or heat; (8) starting sub-group by means of which 
the motor is started; (9) hghting sub-group through which the car is 
lighted, not strictly an engine part but closely allied with starting 
and ignition, and because of its drive from the engine and general 
location of its parts on it, it is classed as an engine sub-group; (10) 
fl^'wheel sub-group. The last is really a single unit but its size, 
weight, shape, location, attachment, and other points are becoming 
so important as to warrant separate consideration. 

Q. Why is it necessary to conskler each of these separately? 

A. Because their. functions all diflFer. The very things which 
make each grou^ best fitted to its work make it more widely different 
from each of the others. Some groups are so very different as to 
warrant separate consideration, almost as extended as the balance of 


the motor group, as, for instance, ignition, starting, and lighting, 
which naturally group together. 

Q. What are the most popular cylinder forms? 

A. Automobile engine cylinders are mainly of the following 
forms: (1) cast in pairs; (2) cast in block; (3) cast in threes, in the case 
of six-cylinder motors. The last is really a modification of the first. 

Q. What are the advantages of each of these? 

A. The cast-in-pairs form can be removed by one man and 
replaced by two, if it is broken, cracked, or damaged; replacement 
is less expensive; the casting is less complicated, consequently there is 
less waste in the foundry; they are easier to machine, store, ship, 
handle; they also have other advantages. All these apply to the 
cast-in-threes modification. The cast-in-block form makes a more 
simple looking engine, a shorter and more compact one, and renders 
alignment and spacing more accurate and permanent. Furthermore, 
all water, inlet, exhaust, and other connections may be cast integral, 
which is not |H)ssible with the cast-in-pairs or cast-in-threes forms. 
Similarly, the crankcase may be cast integral if desired. 

Q. Mow is the weight of reciprocating parts lessened? 

A. In the case of pistons, this may be done in one of three ways: 
0) till.- form, shape, size, ami m:itcrial nmy remain uiicluitipcil, whili 


Q. Is there a noticeable tendency toward simplicity in connect- 
ing-rod constructions? 

A. Yes, the same as in pistons and rings, toward simplification 
and lightening of the weight, with the removal of all superfluous 
pwtrts. Two bolts are becoming the standard for the big end. The 
H-section machined all over is almost universal, smaller sections being 
used than formerly. Pressed-in wrist-pin bearings of comparatively 
thin walls are being used and a better class of material generally, 
which allows lighter weight and smaller sizes for equal or greater 
strength. Lubrication scoops are being machined-in in the forms of 
holds, and a simple projecting lip instead of former brass tubes, 
which were added. 

Q. What is the accepted type of connecting-rod big-end 

A. The split, or two-piece, form with a shell or backing of 
bronze and a facing, or wearing surface, of babbitt with oil holes 
drilled through and the interior surfaces oil-grooved to and from these 
to distribute the oil evenly. 

Q. Why is this the accepted form? 

A. The bronze backing or shell gives the desired stiffness and 
permanence, also machines well and resists overheating well. The 
babbitt facing, when worn, is easily replaced by any repair man, and 
it will melt out in case of lubrication neglect so little harm is done, 
yet when well-fitted it gives a fine bearing surface. The system of 
drilling and grooving supplies a film of oil at all times. These 
materials and this arrangement supply an almost ideal combination 
when well-made and fitted, hence their wide acceptance. 

Q. What difference is noted in V-type engine bearings? 

A. When the two rods of a V-type engine act upon a single 
pin, the arrangement of the bearings must be such that one must be 
notched out, or divided, to make room for the second, or else the 
exterior of the first must be formed as a bearing surface for the second. 
In the former case, the one bearing is practically in four parts; in the 
latter, the exterior of the inner bearing becomes as important as its 
interior surface, since it acts as the bearing pin for the outer rod. 

Q. Name two general forms of crankshaft today. 

A. The single-plane type and the multi-plane type. In the 
former, as used on four- and eight-cylinder engines, all pins, bearings^ 


and webs are in one plane. In the latter, as used on six- and twelve- 
jylimler engines, the pins are in three planes set at an angle of 120 
degreew with each other. 

Q. How many different forms of four-cylinder shafts are 

A. There are but three radically different forms of four- 
cylinder crankshafts, depending upon the bearings. These are: 
(1) The shaft in which there is a bearing on each side of each appli- 
cation of power, or five bearings m all; (2) the form in which there is a 
bearing at each end and one in the middle, or three bearings in all; 
(3) the form in which there are no center bearings, but only the 
two end bearings. The first is used on the highest-priced four- 
cylinder cars, it is expensive of itself and has a similar 
influence on other parts, notably bearings, crankcase, etc. The 
second is in wide use; being the most popular form. The last 
is used only when extreme compactness is desired. There is an 
odd form of shaft in which four bearings are used, but only one 
maker ever used it. 

Q. What is the difference in the average of six-cylinder crank- 


The general type is the same, also the number of bearings. This 
applies to fom^, sixes, eights, twelves, or to any form. 

Q. What are shims, and for what are they used? 

A. Shims are very thin pieces of metal placed between the 
two halves of bearing caps for the purpose of giving a quick, simple, 
easy adjustment when the bearing wears. In theory, this works as 
follows: When a bearing has worn down i( ft o' inch, the cap is un- 
screwed and removed, and shims of a thickness of ttAht inch are taken 
out on each side. Then the cap is replaced and tightened, and the 
bearing is as good as new*. In actual practice, the removal of the 
shims creates a shape of bearing which is not an exact circle, so that 
some slight scraping with very little wear, is necessary, as illustrated 
above, and a great deal of rescraping and refitting (in addition to 
shim removal) with greater wear. 

Q. For what is a crankcase used? 

A. The crankcase is used to support the cylinders and the 
crankshaft; to act as a housing to keep out dust and dirt and as a 
retainer and reservoir to hold the oil in. 

Q. What is its general shape? 

A. Generally, crankcases are either of the box shape or of 
the round, or barrel, type. The first named is generally split 
horizontally along the crankshaft center line; has a flat top and bot- 
tom, with vertical sides; has the bearings supported in the top half 
only, the bottom acting simply as an oil pan. The second form is 
generally in one piece with removable ends in which two of the shaft 
bearings are located; has a rounded bottom in which the oil is held; 
has a flat top but rounded sides. 

Q. Of what material is the crankcase constructed generally? 

A. Aluminum and aluminum alloys are most widely used, 
although there are a number of motors with cast iron, some with a 
cast-iron upper half and a pressed-steel or aluminum lower half, and a 
few of bronze. The latter is expensive and is losing ground. Pressed 
steel is suitable only for quantity production, while cast iron is losing 
ground except in those up-to-date designs in which the upper half 
of the case is combined with the cylinder block. 

Q. How are crankcases supported on the frames? 

A. The most general method on pleasure cars is the casting 
of arms, generally four, integral with the crankcase, these extending 


out to and resting upon the frame, to and through which they are 
fastened. Generally, too, a thin web is cast between the front and 
the rear arm on each side, extending out horizontally from the sides 
of the case to the frame. This serves the double purpose of replacing 
the underpan and of acting as a stiffener for both arms and case. 
On a few cars and on quite a few trucks, a pivoted cross-arm 
is used at the front and a bolt cross-arm at the rear (or rice 
Tema), being forged members. In this way a three-point 
support is obtained, which yields as the frame is twisted or raised 

Q. What is the gear cover and what are its functions? 

A. It is the rernovjible cover at the front end of the engine, 
which covers and protects the camshaft and other gears or silent- 
chain drives. In addition to keeping out dust and dirt from these, 
it minimi7.e3 the unavoidable noises which they make and retains 
the lubricant. It h generally a Hght aluminum shell held on by a 
dozen or less bohs. 

Q. What is the general method of lifting an engine out of the 

A. By a rupr or a chain sling, hoistcil from above by a chain 


locatioQ in the cylinder, and, in part, upon the facilities whidk the 
shop possesses. The best method varies with almost every case. 

Q. What is the most rapid method? 

A. Probably burning out with oxygen is the quickest method, 
when the shop possesses an oxygen-burning outfit. The spark 
plugs are removed and their holes plugged, one or more valve caps 
are removed to allow working, the gas is turned on and lighted, when 
the workman can do a cylinder thoroughly in three or four minutes. 
This means that the entire process of doing an engine will not take 
over twenty-five to thirty minutes. Any other process will take twice 
as long as this. 











Function of the Carburetor* As has been pointed out in the 
general outline of the motor car, the first and most important thing 
in the engine cycle is to get the fuel into the cylinders. This is done 
through the medium of the carburetion system, the principal unit 
in which is the carburetor. The function of this is to convert a 
liquid (gasoline) into gas (gasoline vapor) measure this, and add 
to it the right quantity of air to give proper and complete combustion. 
If this be not done, ix)wer is lost, either through the use of too much 
or too little air. In the latter case, not all the fuel is vaporized, hence 
some of it is wasted. 

This sounds like a simple proposition, yet its very simplicity has 
been the undoing of many automobile experts. The vaporizer 
becomes more and more complex each year, constant additions and 
changes are being made in the other parts of the system, and in other 
ways the carburetion system shows a constant change. Despite all 
this, few fundamental laws have been found to be in error, and few 
new ones have been discovered or developed. ' 

Effect of Heavier Fuels. For some years past there has been 
under way a subtle change in the character of the fuel — the gasoline 
used for the propulsion of automobiles. The small production and 
the increasing demand have combined to render almost unpurchas- 
able, except at high prices and then from large dealers, the lighter 
and more volatile gasolines of some years ago. In the place of them 
there have been quietly introduced much heavier petroleum dis- 
tillates, which evaporate less readily — though they are actually of 
higher value in terms of power units. This condition has compelled 
several changes in the carburetor problem. 

In addition to the foregoing, in some parts of the world there 
have been serious efforts made to utilize in automobile moloi^ 


alcohol and benzene (not henzjne), whicti, with proper provision for 
their carburetion, {-onstitute excellent fuels. 

The most important of the changes dictated by this development 
in the fuel situation is the now general practice of heating the float 
chambers of carburetors, either hy water from the circulating system 
or by exhaust gases. An alternative scheme is that of drawing of the 
air for the carburetor from a point adjacent to the exhaust piping, ao 
that this air is sufficiently warmed to readily take up the gasoline 
necessary to constitute a proper explosi\'e mixture. 

Jacketed Manifolds. A subsequent and verj' successful method of 
handling the heavier fuels is that of jacketing the upper portion of the 
inlet manifold, and the circulating of the hot water in the cylinder- 
cooling system through this. By having this jacket close to the point 
where the gaseous mixture enters the cylinder, any remaining particles 
of liquid fuel are vaporized before entering the cylinders. In a few 
instances, the same effect is obtained bj- incorporating the carburetor 
in the cylinder water-jacket casting. In still others, where the car- 
buretor is placed on one side and the inlet valves on the other, there is 
a cored inlet passage through the cylinder block between the cylinders 
which heats the mixture, with the same result as stated above. 


More Valvet w. Forced Induction. The present-day tendeDcy 
toward the use of many valves, four per eylinder, seems to indicate 
a nece^ty for getting more gas into the cylinders in order to get 
more power and speed from the same size of motor. Thb would 
seem to lead back to the subject, agitated a few years ago and dropped 
for lack of interest, of the need for forced induction. This will 
introduce a greater quantity of gas into the cylinders without resort- 
ing to the complications and trouble-breeding possibilities of four 
valves per cj-linder. It differs widelj- from fuel injection, consisting 
in its simplest form of a special form of fan or blower to drive the 
vaporized fuel into the cylinders. 

Classification of Carburetors. Carburetors, as a whole, may be 
divided into three classes: the surface form, in which the air 
passing over the surface of the fuel picks up some of it, mixes with it, 
and produces an explosive vapor; the ebullition, or filtering, tj'pe, in 
which air is forced through a body of fuel from below, absorbing 
small particles so that when it reaches the top and is drawn off, it is 
suitable for use in the cylinders; and the float-feed, or spraWng, t\'pe, 
under which head nearly all modem devices come. The others have 
gone out of use, as fuels today are too heavy for them to be practicable. 

The original float-feed carburetor consisted of one part besides 
the fuel pipe, float chamber, and passage to cylinder, which made it 
remarkable for its simplicity. It had no adjustments, nor was there 
any way of securing an even and continuous flow of fuel or of air, except 
as the engine suction produced these. The need for these qualities 
brought out, one by one, the modifications of the original ; and through 
continuous modifications and recombinations of these, all the modern 
devices have been developed. 

Defects in the Orisinal Are Not Found in Modem Types. The 
original carburetor had no adjustment; the opening in the casting 
measured the amount of air, while the size of the nozzle measured the 
amount of the fuel and the fineness of the spray. There was no 
means of r^rinding the float valve, and thus no way of assuring 
an even and continuous flow of fuel. The modem adjuncts of -the 
original Maybach device consbt of remedies for these defects, and, 
in addition, a proper means of balancing and adjusting the float. 

To pid( out a modem carburetor at random, take the one shown 
in Fig. 81. Like its ancestor, it has a gasoline chamber into which 



the fuel is admitted by the action of a float, when it first passes 
through a strainer. From the float chamber the liquid passes up to 
and through the spraying nozzle. The weight of the float is so calcu- 
lated that the level in the final nozzle is just 1 millimeter (0.04 inch) 
below the top. This insures that there will always be fuel there for 
the air suction to draw off. As the physical action of changing a 
substance from a liquid to a gas is usually accompanied by the 
absorption of heat, it is advisable to supply a reasonable amount 
of this, and thus assist the change of form. In the older May bach, 
this was inadvertently done by placing the whole apparatus in close 
contact with the hot cylinder. In the modern carburetor, placed 
some distance from the heated portions of the engine, this additional 
heat is supplied by the jacket water. An alternate scheme is to 
pre-heat the air supply by a special pipe from the exhaust manifold. 

From this mixing chamber the mixture of air and gasoline vapor 
passes upward into a secondary mixing chamber. This communi- 
cates with the inlet pipe through the medium of the throttle valve. 
The auxiliary air supply, when used, has access into the secondary 
chamber through the auxiliary air valve. This comes into action on 
ver>' high speeds when the engine is pulling very strongly. At this 
time the proportion of gasoline to air is likely to be too large, so 
the auxiliary opens, admits more air, and thus dilutes the mixture. 

Throttle Valves. Butterfly Type. Whatever the nature of 
the mixture in the carburetor, it is admitted to the cylinder by the 
throttle valve, which may take the form known as the butterfly. 
This is a flat piece of sheet metal, preferably brass, attached to a 
suitable shaft with an operating lever on the external end. 

Piston Type. Besides the butterfly type there are fully as many 
of the piston type. The sliding form is a cylindrical ring or shell of 
metal, which is free to slide in a corresponding cylindrical chamber. 
In the walls of the latter are a number of apertures or ports which 
the longitudinal movement of the piston either uncovers or covers as 
the case may be. Sometimes, to facilitate this action, the* sides of 
the piston are grooved or notched, but this does not alter the prin- 
ciple of sliding a cylinder within another cylinder to cover or uncover 
certain ports in the cylinder walls. 

In addition to the sliding piston, there is the rotating piston, 
working in practically the same manner, that is, its rotation connects 



openings in the piston walls with the interior of the vaporising chamber 
on one side and with the inlet manifold on the other, the amount 
of the opening depending upon the distance the piston is rotated. 
Needle Valves. Xeedle valves — or spray nozzles as they are 
sometimes called because of the function they perform — constitute 
an important part of every carburetor, or liquid -vaporizing device. 
It might be thought that so long as there is a hole by which the fuel 
can enter the vaporizing chamber that is sufficient; yet such is far 
from the case. In addition to the function of an entering hole, the 
needle has the additional duty of breaking the fuel up into a fine 
spray or mist, the particles of which are easily picked up by the 
inrushing air, and as 
easil\ converted into a 
\ apor Therefore, that 
shape form, or arrange- 
ment w hich will divide the 
entering liquid up into 
eJ " = ^ the finest particles will be 
the most efficient. The 
difference of opinion on 
this latter point has 



Tit- 82. Thp F. 


to vary greatly, both as to quantity of fuel flowing, and the extent 
to which it is spread out. When the needle is down very low, only 
its point enters the hole, so that practically the full area of the latter 
is available, the central needle influencmg the column of fuel passing 
out only to make it hollow in the center. 

With the needle raised to nearly its maximum height, however, 
the point projects clear through, and the needle shaft almost fills the 
lower part of the hole. This reduces the flow to a very fine hollow 
column of spray, as the shape of the needle and of the lower edge 
of the hole is such as to force it inward and then outward so that as it 
leaves the top of the hole it is diverging widely. Thus, the effect 
of the addition of the needle is to allow the use of much smaller 
quantities of liquid with the same-sized hole, of diffusing it more 
widely, and of making it adjustable to varying needs. Despite all 
its advantages, only three of the carburetors and vaporizers shown 
use this type; and of these, one is a combination of this with A. 

External Needle Type, The third type shown at C, Fig. 82, is an 
inversion of B in that the needle is made external and descends from 
above into the hole in the nozzle. In this form, the shape of the 
needle point produces the desired diffusion and spraying effect, which 
accounts for its popularity. Of the models shown herewith, nine are 
of this kind, one being a modified combination of this form and A. 

External Sectional Needle Type. The fourth form, shown at* D, 
is like C, except that instead of a needle resting upon the upper 
surface of the hole and allowing a continuous hollow stream of fuel 
to flow, a series of holes break up the column into a number of very 
much smaller columns, each with its own opening. In this form the 
central member may be movable or not, while the holes may be set 
at any angle. Of the examples of this form shown in this article, 
three in all, every one has the holes placed horizontally instead of 
inclined to a vertical, as shown in Fig. 82. Of these, two show a com- 
bination of B and D, This is an effective combination. 

Floats. Another feature of the earlier forms of carburetors, 
which was soon found to be in need of a change, was the arrange- 
ment of the float. In Maybach's original vaporizer, there was no 
means of balancing the float; consequently, there was no way of 
preventing wrenching and breaking of the needle-valve spindle. As 
this disarranged the gasoline supply, it made a change very important; 


and thu proMem rec«ivnl eaHy attention. There was aUo the neces- 
«ity for reiUhle devices to regulate the supply of air and of gaiwline 
spray fn^m the nozzle, either by orij^nal adjustment, by means of 
a governor, or by effecting a constant variation by hand to meet 
constantly varying conditions of mgine demands. 

Thc:% a/ldition.-t to the on'ginal form caused srane trouble. 
The ordinary way of managing the balancing of the Soat, while it. 
may be the cause of trouble at times, is a ver\' simple one. The float 
Li of exceeding lightness, whether made of cork or metal. With 
the inflow of gasiiline in liquid form this float rises, and in so doing 
it strikes against a. pair of small pivoted levers near the top of the 
flout clianiber. The other ends of the pivoted levers rest upon a 
form of shifting collar on the needle-valve stem. So, when the float 
rises above a certain level, it automatically shuts otf the flow of 
ga.<u>line by pressing against the pivoted levers, which, in turn, act 
again^it the stem and press it down until the flow is cut off. The 
float will stay up until the suction of the engine has lowered the 
gasoline level so that the dropping of the float releases the levera 
which raise the nwflle valve ofl^ its seat. The gasoline flow ia thus 
automatically regulated by this balance<l-float arrangement. 


extracted from surrounding objects. This accounts for the frost 
which gathers on the outside of the mixing chambers of carburetors 
which do not have a water jacket or other source of heat supply. 
The heat is abstracted from the air so rapidly that the moisture in 
the air is frozen, appearing as frost on the outside of the carburetor. 

Auxiliary Air Valve. The auxiliary air valve has always caused, 
discussion, its opponents claiming that it means extra parts, and 
therefore more adjustments and more sources of trouble; while those 
favoring it say that without some additional means of this sort for 
diluting the mixture at high speeds, it is impossible to run the engine 
fast, as high speed will then mean an over-rich charge. Be that 
as it may, the fact remains that the weight of opinion lies with the 
auxiliary valve. 

Necessity vnth Heavy Fuels, Practically all the more modern 
vaporizers use an auxiliary air valve, as this is a partial necessity 
with the heavier fuels. That is, it has been found that the heavier 
fuels require more air to vaporize them than can be supplied by the 
primary air inlet. Moreover, these heavy fuels require considerable 
additional heat in order to vaporize, and the auxiliary air inlet has 
been made the vehicle for conveying this. As will be explained in 
detail later on, this is generally connected with the exhaust manifold 
in such a way that the air entering through it is heated to a high 
temperature. Adding this after the fuel has been split up by the 
spraying nozzle and the primary air has proved very successful. 

Usual Forms of Auxiliary Air-Inlet Valve. The auxiliary air 
inlet usually consists of a simple valve, opening inward, held in its 
place by a spring of a certain known tension. The strength of the 
spring is carefully determined so that at the proper moment — when 
the motor requires more air in proportion to the amount of gasoline 
used — the valve will open just enough to allow the required amount 
of air to enter. It will be seen that the time and the amount of 
opening will be controlled by the speed of the engine, i.e., by the 
amount of suction produced by the movement of the piston in the 
cylinder. Of course, as the engine speeds up, there is a greater 
piston displacement to be filled per minute, and therefore it is neces- 
sary to supply a greater amount of mixture. Upon changing speed 
suddenly from, say, 500 revolutions to 900 or 1000, the carburetor 
which does not have this device will no^ give a imiform mixture imme- 


diately; in fact, it might require a new adjustment of the gasoline flow 
in order to supply the right aaiount of fuel. \Vliat the auxiliarj' air 
inlet actually does, then, is to control automatically, above a certain 
point, the amount of air admitted, thereby always maintaining a 
homogeneous mixture. In order to prevent any chattering of the 
valve or rapid changes in the air supply, a diaphragm or a dashpot is 
sometimes used in connection with the valve. 

As a substitute for an auxiliar,^' air vahe, a number of makers 
have tried the use of steel balls, resting in holes about two-thirds the 
diameter of the ball. By varying the size and weight of the balls, a 
truly progressive action is obtaine<l, for light suction lifts the light 
balls, and strong suction all balls. 

Venturi-Tube Mixing Chamber. Like every other carburetor 
part, the spraying action and the shape or size of the chamber in 
which it takes place have been the subject of much debate. Orig- 
inally, the chamber took any convenient shape and varied all the 
way from a pertectlj- plain cylindrical shape to an equally perfect 
square, with all the possible variations in between. A few years 
ago, however, scientists began to look into the vaporizing and equally 
important measuring action of carburetors, with the result that a 


In water meters the contracted area is made one-ninth that of the 
pipe. This same relation, although not exact, holds in the case of 
the carburetor. Since the area varies as the square of the diameter, 
this b equivalent to saying that the diameter of the contraction 
should be one-third the diameter of the full-sized pipe. 

Double-No2zle Type. A distinctive design of two connections 
leading into the vaporization chamber is the Zenith (French) car- 

Fla- 83. ZBnilh Cu-bur«or, Mod*! ■O" 
Cnrtuy q^ ^MilA Carburetor Company, Detroit. Mickiffan 

buretor, a diagrammatic sketch being shown in Fig. 83. This is biit 
a modification, in a way, of the Venturi plan, for the latter shape 
is actually used for the vaporizing chamber. The new idea consists 
in leading into this mixing chamber, two tubes. Of these, one is the 
ordinaiy spray nozzle and does not differ from that used on hundreds 


of other devices. Tlie second, however, is very different. WhOe it 
leads into the same mmng chamber, it does so through the medium 
of a secondary chamber, or standpipe, to which the suction of the 
engine has access. If this suction is strong, more gasoline is drawn 
into the secondary chamber, from which it may enter the spraj- 
ing zone. 

The ordinary nozzle is of an exact size and, consequently, can 
pass only a certain amount of fuel, alwajs at the same speed. With 
the additional nozzle, this does not hold; and being of large diameter 
(comparatively), the flow through it depends wholly upon the engine 
suction, which \arie9 at all speeds, often at the same speed upon 
different occasions. 

Use of By-Pass. This matter of two standpipes has a parallel 
in the use of a by-pass, so-called, around the usual mixing chamber. 
On some carburetors this is made so as to allow easy starting, the 
idea being tiiat when suction is applied to the carburetor by cranking, 
with the throttle closed, practically pure gasoline \apor will be drawn 
through the by-pass. This will start the engine after which, as the 
throttle is opened gradually, its movement cuts off the b\'-pass, until 
at meiiium speeds it is out of use entirely. The same thing applies to 


simplicity, has brought forth a general simplification, or elimination 
of inlet pipes, and a fairly wide use of horizontal carburetor outlets. 
The latter has affected carburetors by requiring a shorter and more 
compact instrument, with a side outlet and a vaporizing arrange- 
ment which will produce tolerably complete vaporization in a 
cttmparatively short distance. To a certain extent, this horizontal- 
carburetor tendency has modified existing practice in nozzles, \ enturi 
tubes, interior areas and arrangements, etc. 

Effect of Heavier Fuels. The growing realization by carburetor 
manufacturers that the increased use of heavier fuels is inevitable 
has brought forth much worthy effort in the way of vaporizing them. 
This has temporarily set aside the kerosene and other heavy-fuel 
vaporizers. However, as the fuel is bound to become heavier and 
heavier, on accoimt of the excessive demands for gasoline, it Is only 
a question of a jear or so before kerosene and distillate vaporizers 
will be agitated again. 

Effect (^ Vacuum Feeds. The wide use of vacuum feeding 
devices, combined with the tendency mentioned above to clean 
and simplify, has caused a much higher mounting nf carburetors. 
This has always been desirable, but hitherto it has not been possible. 
The vacuum feed for the gasoline supply has made this change pos- 
sible, while the cleaning process and simplification actually forced it. 

Effect of Motor Changes. The high-speed form of motor now so 
generally being adopted has had a big influence, as have also the 
multi-cjlinder forms, both creating a demand for greater accelera- 
tion. Similarly, starting devices have forced the use of a carburetor 
modification by which instant starting is possible. These require- 
ments have called for new designs, smaller and lighter parts, more 
nearly complete automatic actions to uncover large air ports, as well 
as other improvements. 

Double Cartniretors for Multi-Cylinder Motors. While many 
eight- and twelve-cylinder motors have but a larger-sized plain car- 
buretor, the better forms have a double device, each half supplying 
a group of cj'hndera, and the halves are entirely separate and distinct 
from the other, except for a common fuel-supply pipe. Each set of 
cylinders has its own suction-actuated nozzle and its own independent 
nozzle. This form has shown its worth in actual use, having been 
verj- successful in aeroplane work on e^t-cyllnder and tweVve- 


cylinder motors, and also on a number of the better eight- and 
twelve-cylinder motor cars. 

Multiple-Nozzle Carburetors. Another development brought 
about by this demand for rapid acceleration, coupled with great 
maximum capacity, has been the swing toward multiple nozzles. 
As has been pointed out on previous pages, there are a number of 
carburetors now with two nozzles. 



Stromberg Carburetors. Fig. 81 shows a cross-section of the 
Stromberg Model "H". Except that Model "HA*' has a water 
jacket around the upper portion of the vaporizing chamber, the two 
are identical; and the following method of adjustment for Model 
"H" will apply equally well for Model "HA'\ Similarly, Model 
"HB" uses the same units throughout, and is of the same design, 
but differs slightly because it is designed for a horizontal outlet. This 
necessitates turning the float chamber unit out at right angles with 
the other chambers. The only other difference in the two forms is 
that Model "HB*' has the low-speed adjustment, marked Primary 
Nozzle Needle Valve in Fig. 81, threaded so that it works in the reverse 
direction. Otherwise the following directions apply to it also, and 
reference will be made to this single difference of adjustment. 

General Instructions, Instructions for Models **ir', **H A'*, and 
"H B". The float-level adjustment is set and locked at the factory. 
It seldom needs readjustment. Similarly, the air-valve spring adjust- 
ment is set and locked at the factory and seldom needs to be touched. 
There are but two adjustments; that of the primary-nozzle needle 
valve, which controls the low speed. This is a simple needle valve 
seating on the inside of an open nozzle, similar to Fig. 82 B, the open- 
ing of which is usually two sizes larger than is ordinarily necessary. 
This permits of an increase in fuel flow to that extent, but it can also 
be shut oflF entirely. If the carburetor is furnishing too rich a mixture 
at low speeds as indicated by "rolling'' or **loading'\ turn this needle 
up, or anti-clockwise (clockwise on Model ^'IIB"). This will admit 
less gasoline and make a leaner mixture. On the other hand, if the 
mixture is too lean, turn this needle down, or clockwise (counter- 
clockwise on **HB''). This will admit more gasoline and make the 
mixture richer. 


The second adjustment is of the auxiliary needle valve, which is 
called the high speed because it controls the flow of gasoline at high 
speeds by regulating the time when the secondary needle valve begins 
to open and add its quota to the total mixture. If the running of the 
motor at high speeds indicates too lean a mixture, advance the spark 
and open the throttle so as to run the motor at a fairly high speed, but 
not at its maximum. Then loosen the needle-valve lock by means of 
the lock screw and turn the needle valve up, or counter-clockwise, 
until the speeding up of the motor shows the desired result. This 
should be accomplished gradually, giving a slight turn, noting the 
speed obtaiped, adding another slight turn if this is not sufficient, and 
noting the speed which this gives. Try to obtain a good high speed 
without attempting the absolute maximum. When the mixture is too 
rich for good results, turn the needle down, or clockwise. When the 
desired result is obtained, lock the needle valve in place by means of 
the lock screw. 

Preliminary Adjustments, Before any of the adjustments 
described above are made, it is assumed that the motor is running well 
and is in good condition throughout. Xhe same is true with the 
carburetor, except for a slight lack in richness or leanness at low or 
high speeds. The following preliminary steps are advisable: Before 
starting the motor, open all pet cocks on the carburetor, so that the 
inflow of fuel will clean out any dirt or sediment in the packing or 
elsewhere. Set the high-speed adjusting nut so that there is at least 
)fSr-inch clearance between it and the needle-valve cap above it when 
the air valve is on its seat. The necessity for this lies in the fact that 
I the needle valve does not begin to open until this high-speed adjusting 
! nut comes into contact with the needle- valve cap. With a dashboard 
I adjustment, be sure that the rocker arm on the carburetor to which 
the adjustment rod is connected is not in contact with the collar 
; above it when the control on the steering post is all the way down. 
Starting Adjustments. To start the motor, raise the steering-post 
control to its highest position. This produces an extra rich mixture, 
but in cold weather it may be necessary, in addition, to close the air 
supply in the hot-air horn (right-hand figure in Fig. 81). As soon as 
the motor has started, however, this should be re-opened. As the 
motor warms up, the steering-post control should be lowered grad- 
ually. If the carburetor is to be adjusted at this time^ be aur^ tk\& 



steering-post control is at its lowest position and the motor thoroughly 1 

Changing Nozzles. WTiile the makers equip the carburetors at 
the factory with nozzles of a proper aize, there are times when peculiar 
or unusual conditions seem to make a different size of nozzle nec'essi 
Before changing nozzles, howe\'er, the ignition sjstem should be 
checked up in every particular, all manifolds and valves examined for 
leaks, and all other contributing factors investigated thoroughly. 
The repair man can judge from actual conditions when a change is 
needed. Thus, when a normal motor in good condition necessitates 
more than two and one-half turns of the primary needle valve to make 
it idle properh', it indicates that the primary- nozzle is too small and 
should be replaced with a larger one. To change this, take out the 
needle valve, also its stuffing box. Then insert a long screwdriver and 
unscrew the nozzle. Then put in the new nozzle in the same way and 
replace stuffing box and needle valve. Never change nozzles by 
more than one size at a time. The opening in these gets smaller as 
the number increases; thus No. 59 is smaller than No- 5S. If a 
No. 59 is not large enough, cliange to a No. 58 and then trj- this 
out thoroughly before proceeding next to a No. 57. 


izing chamber. In such a case it is advisable to take the matter up 
with the Stromberg Company and get a correctly made but special 
air-valve top. 

Stromberg '*K** Models. This company also makes a Model 
"K" carburetor; while Model "KO" differs only in that the attaching 
flange, used to fasten the carbmretor to the inlet manifold, is tiurned 
at right angles. Model "KO-l" is similar to Model *'K0", except 
that it has a few slight modifications which enable its immediate 
application to the Overland car, Model 81, without any changes, and 
to other Overland Models with similar ease. The illustration. Fig. 
84, shows Model "KO", in which it will be noted that the general 
construction is very similar to the "H" models, except that the float 
is concentric. This saves parts and manufacturing cost and is a 
low^er-priced model. There is an idling tube which runs up through 
the middle of the main vaporizing chamber, and the needle valve is 
horizontal instead of vertical, but otherwise the device follows stand- 
ard Stromberg practice, except as the concentric float modifies it. 

Adjusting the **X" Models. The air-valve adjusting nut cor- 
responds to the high-speed adjusting nut on the "H" Models. This 
is the only adjustment of the "K" Models; the stem of this nut sup- 
ports the lower end of the spring which controls the air valve that 
opens downward into the air chamber. Turning this nut clock- 
wise, or down, tightens this spring and admits less air. This produces 
a richer mixtiure. To obtain a leaner mixture, it should be tiurned 
counter-clockwise, or up. Before starting the motor, this nut should 
be turned counter-clockwise to a point where the lifting of this nut 
results in a slight click (the air valve coming into contact with its 
seat). Then the nut is turned clockwise, or down, notch by notch, 
until this click is no longer obtained. Then the nut should be turned 
two full notches more. 

After the air valve has been set, and when the motor has been 
warmed up, this nut is turned one notch at a time, in either direction, 
until the motor idles properly. This is the low and intermediate 
speed adjustment. High speed is controlled by a fixed nozzle and 
can be changed only by replacing this with a different size of nozzle, 
on the Model "K". This is done by unscrewing the pet cock at the 
bottom^ inserting a screwdriver and unscrewing the old nozzle. The 
new is put in place in the reverse manner. The repair paau oa^ dt^\^X 



the need for a change of high-speed nozzle as follows: If the mixture 
on high speed is too lean, so that slightly closing the dash-control 
valve increases the speed, then a larger nozzle is needed. If the high- 
speed mixture is too rich, a smaller nozzle should be used. 

On the "KG" Models, the nozzle needle valve projects from the 
side of the fioat-chamber casting at right angles. With the motor 
varm, the spark and throttle should be set to correspond to about 
twenty-five miles an hour. Tlien this needle valve is turned as necesr 
sary to give the best motor speed. 

Zenith Carburetors. The Zenith Model "O" carburetor, shown 
in Fig. 83, enjoys wide use in this country because of its simplicity. 
It has fewer ordinary adjustments than any other carburetor. This 
is so constructed that but one adjustment, that for slow speed, is 
provided. However, its makers realize that sometimes changes and 
adjustments are necessary to secure proper results. They provide 
for these by the removal of three internal parts and their replace- 
ment with simpler parts, but with different working orifices, 
or holes. 

Zenith Adjuatmxnts. The three parts mentionetl are: choke 
tube, main jet, and compensator. In Fig. 83, the choke tube is 
marked X. This is really an air nozzle of such a stream-line shape 
(approximating the Venturi) as to allow the maximum flow of air 
without eddies and with the least resistance. When the pick-up, 
or acceleration, is defective and slow-speed running is not smooth, 
the choke tube is too large. In this case, it will be found that a 
la^er compensator I does not better the situation. Then a smaller 
choke tube is needed. This is held in place by a screw Xy in the 
choke itself with a lock washer to prevent its jarring loose. To remove 
the choke, the butterfly T must first be removed. In the horizontal 
tv-pes, the body is in two pieces, which are held together hy an assem- 
bling nut. When this is removed and the two pieces taken apart 
(the bowl from the barrel), the choke can easily be slipped out of 
the barrel. When the motor will not take a full charge, that is, when 
it cannot, with the throttle fully opened, this indicates the need for a 
larger choke tube. It will be noted that although the pick-up is 
good, the car wUl not make all the speed of which it is capable. In 
this case, take out the choke tube X, as explained above, and replace 
with a larger one. 


Changing the Main Jet. The main jet G, Fig, 83, shows its 
influence mostly at high speeds. Wlien running at high speed on a 
level road, if the indications show a rich mixture, irregular running, 
characteristic smell of over-rich mbrture from the exhaust, firing in 
the muffler, sooting up of the spark plugs, and low mileage, the main 
jet is too large and should be replaced by a .smaller one. On the 
other hand, when running at high speed, if the indications are that 
the mi.xture is too lean, if the car will not attain its maximum speed, 
if there is occasional back firing at high speed, then the main jet is too 
small and should be replaced by a larger one. In respect to back 
firing, howe\er, care should be used, as this is more often due to large 
air leaks in the intake or valves or to defects in the gasoline line. 

To Replace Main Jd. When it is necessary to change the main 
jet 0, Fig. 8i^, to a larger or smaller size, the lower plug L is removed 
first. This has a square head and is removed with a wrench. Then 
the main jet is unscrewed from below by means of a screwdriver, a 
notch being cut into its lower part for this purpose. In reassembling 
care should be taken to see that the fiber joint packing is on tlie jet 
and that the jet is screwed up far enough to compress this. Otherwise 
jasoline may leak around the threads. But one fiber washer should 



lower surface. In connection with this last method of adjustment, 
the makers recommend that the workman should start with the 
setting provided, then proceed to determine first the main jet, then 
the compensator, then the choke. In a sense, this method makes 
double work, for any change in the choke calls for a corresponding 
change in the main jet, but it gives superior results. 

ShuySpeed Adjustment. The one adjustment in the Zenith 
device which is really an adjustment and not a change is that for slow 
speed. This is preferably made on the garage floor, with the motor 
properly warmed up. When this has been done and it has been 
throttled down to idling speed, any irregularity, such as the lack of 
ability to throttle down to a really slow speed (say 350 or less r.p.m.), 
calls for a change in the adjustment. When the throttle T, Fig. 83, 
is nearly closed, there is considerable suction at the edge, and the tube 
J in the top of the secondary well P terminates in a hole A near the 
edge of the butterfly at which gasoline is picked up. If the motor 
will not throttle down as slowly as it should, the supply of gasoline 
can be reduced bv means of the external milled screw 0. When this 
is turned in, the air entrance N is restricted, and consequently a richer 
mixture is drawn in. When it is unscrewed, or turned out, a larger air 
opening is uncovered, and consequently a leaner mixture is drawn in. 
In this connection, many factors other than the correct slow- 
speed adjustment of the carburetor may prevent good idling. Some 
of these are: too light a flj^wheel, too much spark advance, and air 
leaks created by (1) poor gaskets, (2) loose valve stems, (3) pitted or 
scored valves, (4) leaky valve caps, (5) spark or valve plugs, (6) leaky 
priming cups, and others. Obviously, if any of these faults exist, 
no amount of adjustment of the slow-speed device on the carbiuretor 
will give good idling. 

HorieorUcd Type AdjvMments and Changes. Everything that has 
been said thus far applies equally well to the horizontal ty^ shown in 
Fig. 85, except for the adjustment of the idling jet. In this form, the 
idling jet Pj is supported by the kniurled nut which governs the air 
opening for this jet, and replaces the horizontal milled screw. 0. 
If a leaner mixture is desired, this is turned to the right, or clockwise; 
this lowers the jet and increases the size of the available air passage. 
For a rich mixture it is turned the other way, or. counter-clockwise, 
reducing the air opening. 



Float Removal. In both models, it will be noted that the float 
cover is held on by the spring catch. This is lifted by means of 
its handle, and swung around out of the way. The float cover 
can then be lifted readily by means of the knurled edge. When this 
is removed it should be lifted up straight. The float is then exposed 


throttle valves are mounted on the same shaft and work in unison. 
TTie device is intended for eight- and twelve-cylinder motors and is 
rigged up generally with a pair of separate inlet manifolds, one for 
each group of cylinders. 

Adjustments. The adjustments on this double Model "O" are 
the same as on the single Mode! "O". It will be noted that the 


slow-speed adjustments are through milled headed screws 0. One 
of these projects horizontally on each side, the same as on the single 
model. To make this adjustment, the motor should be started and 
warmed up; then the spark plugs on one group of cylinders are dis- 
connected and the slow speed adjusted for the other set. Then the 
process is reversed, with the other set of plugs disconnected, and the 
second group of cylinders adjusted. 


As the adjustment is changed, a difference in the idling should be 
noticed. If the motor begins to run evenly or speeds up, it shows that 
the mixture becomes right in proportion, but that there is too much 
of it. This is remedied by changing the butterfly throttle position 
slightly, closing it by screwing out the stop screw which regulates the 
closed position for idling. Care should be taken to have the butterfly 
held firmly against this stop at all times when idling the motor. If 
the single group of cylinders being adjusted seems to run irregularly 
after changing the position of the butterfly, another adjustment of 
the knurled screw may have to be made. After one group of 
cylinders has been made to idle satisfactorily, the same procedure 
should be repeated with the other group, that is, each half of the motor 
should be adjusted for idling independently to about the same speed. 
The single thing which is radically different and must be remembered 
in this cormection is that multi-cylinder engines have very light fly- 
wheels and reciprocating parts, so the motor is extremely sensitive 
at low speeds to unequal conditions of ignition, compression, and air 
leaks. This makes it more necessary than with a plain four- or six- 
cylinder form to have the motor in the best possible condition before 
changing the carburetor idhng adjustment. 

Carburetors on Ford Cars. On the Mtiilel "T" Ford car. 



tbence out to the motor via the mixture outlet /. In this, its quan- 
tity is governed by the throttle, the lever of which may be seen at 
J. In the air intake, there is a throttle plate K, which deflects a 
la^ part of the entering air so that it passes to the right (straight in) 
and .is added to the mixture in the mixer chamber. This forms 
the auxiliary air valve. The position of this plate, governed by the 
auxiliary throttle lever L, determines the quantity of both the 
primary and auxiliary 
sir, since by its position 
it splits the entering air 
into two parts, one of 
which becomes the pri- 
mary air, and the other 
the auxiliary air. For 
low speeds and idhng, 
the low-speed tube M 
carries the very rich mix- 
ture up direct to the 
mixing chamber and thus 
into the engine. 

Ford Adjustment 
This Holiey model, like 
the Kingston, has butone 
adjustment. The needle 
valve B, which has a pro* 
jecting knurled head A 
for turning it, has a con- 
ical point C which seats 
mto the fuel opening. If 
this is seated, no gasoline 
can enter, but as it is 
screwed out or up an opening is created and increased, which allows 
fuel to flow. The amount of this determines the amount of mixture 
entering the cylinder combustion chambers. Consequently, the 
primary adjustment with this screw is that of the fuel flow. Air 
enters through the opening H, passes the throttle K, and then mixes 
with the fuel spray, diluting it and carrying it up into the cylinders. 
The funount of the air b governed by the air lever L, its position 



being arlju-stetl at the factor^-. The adjustmeots as recommeDded 
by the FonI Motor Company are as follows: 

Initial Adjustment. The usual method of regulating the carbu- 
retor is to start the motor, advance the throttle lever (on the steering 
wheel) to about the sixth notch, with the spark lever (also on the 
steering wheel) retarded to about the fourth notch. The flow of 
gasoline should now be cut off by screwing the needle ^-alve down 
(to the right) until the engine b^ns to misfire; then gradually the gasoline feed by opening the needle valve until the motor 
piclc* up and reaches its highest speed and until no trace of black 
smoke comes from the exhaust. Having determined the point where 
the motor runs at its maximum speed, the adjustment should not be 
changed except as indicated below, 
^-■-■'^ ~--^ Ffi-r averagi^ results, a lean mixture 
will give better results than a rich o 

Dash Adjustment. The gasoline 
adjustment is placed on the dash. 
Fig. H8, the mill«l head shown being ' 
fastened to a long rod whose lower 
I end is attaclied to the nee<lle \'alve 
head .1. Fig. S". Any movement 



Oflier HoUey Carburetors. Aa has been stated, the carburetor 
illustrated in Fig. 87 and just described is a Holley Model "G". 
Thisfinn also markets a Model "H", which is very similar to the "G", 
as will be noted in Fig. 89. The biggest differences between these 
modeb are: the vertical outlet in place of a horizontal; and the 
placing of the needle valve at the bottom because of this. In this 
latter figure, fuel enters by the gasoline pipe through the strainer A, 
past the float valve B, into the float chamber D, the level being 
t^ulated by the movements of the cork float C. Prom there, it 
passes through the opening F into 
the nozzle well E, through the 
hole H past the needle to a level 
m its cup-shaped upper end which 
just submerges the bottom of a 
nnall tube J, with its outlet at the 
edge of the throttle disc K. When 
the engine is cranked with the 
throttle nearly closed an energetic 
Sow of air past this point draws 
liquid fuel which is atomized upon 
its exit from the small opening at 
the throttle edge. 

As the enpne rotates, consid- 
erable air is forced to move through 
the conical passage outside of the 
atrangling tube L. The shape of 

ji J «i_ 1 ) Fi«. SO. HoUey CBrburetoi. Model "H" 

the passage around the lower end coi.rt«» <./ noii,y fl™i*<ri coxpanv. 
of this is such that the entering Dnrou. nu^kxmt 

air attains its highest velocity, and thus lowest pressure, near the 
upper end of the standpipe M. Consequently, there is a difference 
a pressure between the top and bottom of this pipe, and the air 
lows downward through the series of holes N. At the bottom it 
:unis sharply upward, picks up the fuel spray there and passes into 
he main vaporizing chamber above 0, and thence past the opened 
brottte into the inlet manifold at P. 

AdjustmeTii. Aa will have been noted, there is but one adjust- 
oent, that provided by the movement of the needle valve /. When 
his is screwed to the right, or clockwise, the valve moves upvaxd 



and reduces the size of the fuel opening. When turned backward 
to the left, or counter-clockwise, it increases tlie opening and admits 
more fuel. The effect of these changes in its setting are claimed by 
the maker to lie manifest equally over the whole range of the motor. 
Acctirfling to the maker, this desirable feature is the result of utilizing 
In the nozzle action the pressure drop due to velocity of flow rather 



wann mooths. Ilis oecesaitates s means of varying it. There is no 
bettN source of heat than the handy exhaust pipe where heat is 
going to waste, so the HoUey device, as illustrated in Fig. 90, utilizes 
the exhaust pipe as a source of heat and leads the same to the carbu- 
retor through a flexible tube with a r^ulating valve at the lower, or 
carburetor end. This is regulated by a simple rod connection with 
a small handle which pro- 
jects through the dash and 
has a dial behind it. This 
ran also be used as a strang- 
hng valve to assbt starting, 
as shown above at A, for 
hot-air supply m winter, as 
at B, for half cold air in the 
spring and fall months, and 
for all cold air throughout 
the summer -months. 

Kii^ton Carburetcws. 
fncfojed Type. The King- 
ston enclosed type, as shown 
in Fig, 91, differs from the 
tj^pe previously shown in 
that the auxiliary air valves 
in the form of various sizes 
of steel balls are used. 
Heae are normally seated, 
but they aie lifted from 
tbeir seats by increased suc- 
tion. The primary air valve 
is not radically different 
from the former model, but the passage of the air is vertical 
rather than at an angle. When the suction lifts the ball valves/more 
air is admitted. This joins the partially vaporized mixture at the top 
of the vaporizing chamber and completes the vaporization and dilution 
befwe passing the throttle valve on its way to the inlet manifold. Like 
the model previously shown, it has the cup-shaped needle recess, so that 
when the motor is shut off, a pool of fuel collects there; this makes 
starting easy, for this fuel is drawn directly in, almost without ^utvoii. 

Kt- «. Pl»ii 

ComrUtm of Bame. Kittttton t 
Kot^mo. Man, 


Adjustments. If the float is found to be too high or too low, it 
can be adjusted readily by bending the float lever to which it is at- 
tached. The oniy other adjustments are: the setting of the throttle 
which governs the lowest speed, this being accomplished by the screw 
shown on the throttle-lever arm projection at the left; and the setting 
of the needle valve for satisfactory high speeds. This is accomplished 
by unscrewing the cap to which the needle is attached and allowing 
more fuel to flow. Continue until the highest speed is reached and 
passed, then turn back until the maximum speed is reached. 



fuels, it has been found that after a certain time the engine begins to 

pound, but that if cooling water he introduced with the mixture, the 

en^e will run cooler, and this pound will disappear. To remedy 

tius is the function of the water valve. 

Adjustments. Adjustments and repairs for this model will be 

exactly the same as with the previously described enclosed model, 

since it is simply two of these joined together. As has been stated, 

the added water valve works automatically. 

Kingston Model "L," The last Kingston model shown, that of 

Fig. 93, is very similar to the Ford model, except that it is formed 

with a vertical outlet, and 

the ur valve B added in the 

vaporizing chamber so formed. 

This is hinged at the side so as 

to be swung upward by the 

suction of the motor, thus 

uncovering a larger and larger 

orifice. It is weighted and 

acts automatically. It will he 

noted also that the shape of the 

nozzle has been altered slightly, 

that on the Ford model being I 

perfectly straight. Near its 

lower end, it passes through 

the low-speed tube C, which , 

has a series of holes around 

the bottom and an annular 

space around the body of the needle. Through this space the fuel 

and a very little air are drawn for starting, as, at that low auction, 

the valve B would be entirely seated. 

Adjustments. After retarding the spark, opening the throttle, 
loosening the needle, and starting the motor, let it run at a fair speed 
long enough to warm up. Then adjust the needle valve. Close the 
throttle by adjusting the stop screw in the throttle lever until the 
motor runs at the desired idling speed. Adjust the needle valve towards 
the seat slowly until the motor begins to lose speed, which indicates a 
weak mixture. Now adjust the needle valve away from its seat until 
the motor attuns its best and most positive speed. This should 

' Fie. S3. Section o[ Kingston .Model "L" Carburetor 
aurfiif 1^ Bgrm. Kinj^m and Conpast, 



complete the adjustment. Close the throttle and let the motor idle, 
then jerk it open rapidly. The motor should respond readily. If it 
does not respond, a slight further adjustment may be necessary. 
When the adjustment has been made, lock it. Float troubles may be 
remedied in the same way as for the enclosed model. 

Browne Carburetor — One Adjustment An entirely new idea 
iu carburction has been produced in the Browne carburetor, which is 


|BB Jj HI I 




>ntent3 erf the motor, while the fiange is of the screwed-on 

that it can be made of a size to fit the motor, 
^ond this radical departure, the Browne device shows another 
startling innovation. It has but one adjustment— the 
of the needle valve for proper fuel supply — and this, once set 
y, need never be changed for altitude or temperature. 
vtruetion. To explain the construction which allows of these 
epartures from ordinarj- practice, refer to Figs. &4 and 95. 
■mer shows a section on the center line, and the latter an 
I view, which is taken from the opposite side to that of Fig. 94. 
M the fuel flows from a float chamber P of conventional design 
fuel nozzle by a 

not shown, but 
■d, in Fig. 95. 

located in the 
if a Venturi pas- 
ffith a 30-degree 
h and a 7-degree 
;e. The area 
mall and insures 
it velocities at 
^speeds to atom- 
fuel. Two fac- 
idi go to make 
QJecting force on 

nozzle are: the 
, created by the 

.uction; and the velocity of air flow. Both of these are made 
ipon the air valve E in this device by introducing the vacuum 
r F beneath the vah'c and connecting it to the vaporizing 
r by the opening //. In this^a ball serves as a valve, 
this manner, the air, at any veliicitj' of flow, is transmitted to 
valve, which, through its position, influences the amount of 
y air admitted. In the upper part of the carburetor, it will 
d that the auxiliary air flows in through the openings on the 
ide of the cover B, over the curved bushing C, and past the 
Jges of the air valve E, to the mixing chamber 1'. Obviously, 
;ine suction is transmitted to E, so that both forces working 

on the nozzle work on the air valve as well. In the air valve, whidi 
is made of aluminum, the curve of tiie bushing C is so constructed as 
to always admit the right amount of air, but with varying velocities. 
This b an important feature, for air valves generally are considered 
to open too far at high speeds. What actually happens is that the 
velocity is reduced too low, and not enough fuel flows. As pointed 
out above, this device, by increasing the velocity of inflow, overcomes 
this defect. 

Waier-Jaek-efing. Water-jacketing on this device is a necessity 
to proper and continuous operation, hence liberal jackets are supplied. 
In addition, pre-heating of the primary air is considered a necessity, 
so a targe hot-air horn is supplied at K for the attachment of a hot-air 
connection to the exhaust manifold. This heating Is very carefully 
set down by the makers of this device as follows: The temperature of 
circulating water is practically constant, summer and winter. Such 
heatsupplied to theoarburetorgivestwo things: a constant tempera- 
ture of the fuel passing the nozzle, which is necessary in order to get 
accuracy of flow ; and a rapid evaporation of anj' fuel that is deposited 
as a film upon the hot walls, which thus increases the economy of 
the device, 

Adjuating the linimifi. As has been stated, the Browne has but a 
single adjustment. This is the needle valve, the projecting milled 
head of which can be seen in Fig. 95, while the point can be noticed 



*el C ' It operates on the constant vacuum principle. This 
acuum is maintained by the pressuredue to the weight of the valve W. 
lis valve restsin anannular opening with its seatEof Veoturi section, 
ut the actual openings are a series of holes J opening onto the face of 
lisehamberfi. The operation iaasfollows: Gasolineflowsinfromthe 
lel supply pipe at the top D, then downward into the float chamber as 
Imitted by the fioat valve which is attached to the top of the float 
. From the float chamber, the fuel passes through radial holes Q to 

e well at the bottom G. At the bottom of the central valve N, 
a nozzle H, through which the fuel is metered, or measured, 
le fuel then passes up through a central oriflce to the outlets into the 
aituri at J. The air enters through the flexible tube from the 
haust manifold where it is heated, passes into the outer bowl C 
me it circulates around the fuel in the float chamber and heats 
at, then rises around the sides and over the top of the chambeT 


which the fupl enters completely vaporize it and iDtimately mi 
witli the pre-heated air. Above thi3, the enlarged space in the di 
B gives further provision for the intermingling of the sirandgaso 
spray before it passes into the motor through the horizontal ou 
which contains the butterfly throttle R. 

Adjustment. The amount of fuel picked up is controlled by 
velocity of the air past the nozzles, which, in turn, is govtmed by 
sjK-ed and consequent suction of the motor. Consequently, a pi 
tically imiforni mixture is maintained throughout the entire sp 
range, accorfiing to the makers. The central portion of the valvi 
is expanded to form a piston which is submerged in the well ful 
fuel at (1 and tlien'bj' prevents the fluttering of the valve. A sii 
screw A', with marked locked screw L, is provided for adjustm< 
This is, in el!re<-t. a stop for the air valve and operates through 
me<liuni of the clip M, the inner ends of which fit into and move n 
the air valve /'. This stops the downward movement of the val 


oi^ue leading to the inlet manifold, an 
below it through which the air enters, hot- 

The air enters from the right, Fig. 97 
sage^ to match the general shape of the c 
This has led to the development of a var 
the air; for a division in the end of the p; 
cold air, half cold and half hot, or all hot, a 
fuel conditions under which the device was 
arrangement was used. Except in the 1 
would be most desirable, but there are cc 
semi-hot air arrangement would be best. 

Adjustment. While it is said not to ha 
is a variation which corresponds to the adj 
retors. .This is the air damper, which is a louj 
ing across the incoming air passage parallel 
connected by means of a Bowden wire me< 
lever on the steering post in the position wli 
adjustment is located. When this is moved, 
over toward, or away from, the distributor. 
or increases the ieiir passage at the jets. Wh 
so as to restrict the passage of air, its veloc 
greater suction carries up more fuel from fV 


« — • 1 



ids which are built to use distillate selling at 6 cents a gallon, in 
irel lots. This fuel has a specific gravity of 51 at 60° F. 

When made for Ford cars, this device has only 11 nozzles. On 
e larger sizes from 14 to 19 are employed. The use of this device, 
.tb its vertical opening, necessitates a special inlet manifold to replace 
at on the Ford which provides for a horizontal carburetor outlet. 

Edwards Carburetor. A decidedly different yet most interesting 
!vice is the Edwards carburetor, made by the National Carburetor 
ompany, of Chicago. This is shown in Fig. 98. The first thing to 
Ae is that the spray nozzle and needle valve A are set at an angle 
' 30 degrees from the 
irizontal. In addition, 
lis forms but the inner 
id of the mechanism by 
hich the nozzle opening 
made self-controlling, 
t the outer end is a bel- 
ws chamber with a col- 
paible bellows B con- 
»ted by means of the 
lasage F to the mixing 
lamber below the throt- 
.'. In this way, the 
essure on the bellows is 
irays that of the mixing 
amber. The shaft, if 
might be called that, which has for its lower end the needle valve, . 
piided by means of the weighted piston C. In this way it will be 
ted that this unit governs the fuel opening. Note also that the air 
ters at /> on a curve, and that the piston C by its position also 
verris this air opening. When at rest, the weight of the piston keeps 
Jown so that it is but A inch from the Jet, the latter being practi- 
Uy cut off. This gives a great rush of air at the start, but as soon 
the throttle is opened the pressure in the mixing chamber falls, so 
it the bellows contracts, drawing up the needle and the piston, 
IS giving more fuel and air at the same time. With still greater 
:tion, the [nessure goes even lower. This device will itse keioaeue 
<tily if the air enterinjr Bt D is pre-beated. 

C«.rt„t 0/ A 

are there any other variables. 

Sunderman Safety Carburetor, 
from other carburetors in several respe 
like shape very different from the us 
pair of central jets, set side by aide in tl 

air enters at one end, and the mixture t 
inlet manifold. The fuel enters the i 

Fi<r P9 show« TI.P nmn.inf != rf.« 


pressure of this spring, which can be varied at will, forces the rod down 
against the air door; this regulates the amount of air which can enter. 
Beyond the jets is a V-shaped screen against which .the mixture is 
thrown, and at the far end of the mixing chamber is the outlet con- 
nection to the manifold and throttle valve. The device, it is claimed, 
will feed pure combustible gas to the motor from cold kerosene or gas- 
oline without changing the adjustment and without the addition of 
heat through hot-air supply or hot-water jacketing. 

Adjustments. On top of the carburetor will be found a projecting 
rod 1, a spring container 2, lock nut Sy and clamp for rod 4- To ad- 
just, take hold of the spring container 2 with the right hand and of the 
lock nut 3 with a wrench in the left hand and loosen it. Then turn 
the spring container to the left, admitting more air. Give it as much 
as the motor will stand without popping back, then tighten the lock 
nut. Let the motor idle for five minutes, then open the throttle 
suddenly. If the motor loads up, loosen the screw in the clamp 4 and 
raise the rod 1 a trifle. This will admit a little more air when idling 
and prevent choking. These are the methods used to control the low 
and high speeds. The butterfly throttle lever arm carries a nut and 
screw 5, which controls the distance it can move. It should be turned 
to the left for a low throttle and to the right for a higher throttle. 
The nut forms the lock. There is no gasoline adjustment. As the 
two jets are screwed in from below, they could be changed if desired, 
by screwing out the plugs first and then the jets, which are notched 
for a screwdriver. The V-shaped screen gives the device its safety 
claim, for the flame generated in back-firing cannot pass back 
through this. 

Longuemare Carburetor. The device which bears the name of 
this famous French expert is now made in the United States. It is 
of a modem design suited to American conditions. The carburetor, 
as shown in Fig. 100, has no moving parts and, beyond two settings, 
no adjustments. It is a single-jet t^^pe, but of a construction which 
gives the benefits of double jets, one central and vertical, the other 
ftnniilftr and opening horizontally. The fuel enters from the gasoline 
line, passes through a strainer and through the openings u down into 
the float chamber, thence through the openings c and d into the niavw 
fuel diannel A, The Bow into this channel is controWed b^ \\v^ xv'eft^^ 
valve m wbicb is adjusted by the external thumb scww M . ^xsl 




filling this channel, it also fills the narrow vertical passage e leading 
into the compensating chamber a, and fills this chamber almost to 
the level in the float chamber. At the other end, it flows up the , 
smaller, or idling, jet j, and the larger, or main working jet i, as the 
fuel rises in both these to about the float-chamber level. 

Operation. In the closed position of the rotary throttle, which 
this figure shows, the fuel flows out of the top of the central jet into 
the small chamber k directly below the throttle. This gets its air 


thit it takes little or no part, as the volume of fuel entering through it 
is n^ligible compared with the great quantity entering through the 
main jet. The very strong suction on the main jet works backward 
along the supply line until all the fuel is drawn from the vertical 
compensating chamber a, when additional air is drawn through this 
from the air holes / at the top. This vertical passage conveys fuel 
to the vaporizing chamber when the throttle is opened and, later, air 
as the motor is speeded up. The air must pass through the fuel 

Tw, 101. Eilcru] View of the Loncuemnre Cnrburctoc. Showing Adji 

diannel k and the jet t, so that it helps to break up the fuel and form 
a gas before the jet, which usually performs this function, is reached. 
I^e saturated gas discharged from the working jet is further diluted 
by the large volume of air rushing through the main air entry x. 
AdjiutmerUa. There are two settings to be made, after which the 
LoDguemare needs no adjustment. With these two settings^made to 
the satisfaction of the operator of the car or motor, the device is 
entirely automatic. There are no jets to change, no dash or steering- 
post adjustments, and no changes to make for differences 4n tempera- 
ture and altitude. The adjustments or settings are (1) for starting 
and idling, and (2) for speed. They are independent of each other, 

iStarting and Idling Adjustment. R 
starts with the throttle closed, so make c 
ing on this adjustment. In this close( 
A A, Fig. 101, rests against the set sci 
on the side plate. In the full open pos 
the lug L on the other side of the plate, 
screw R on the left side of Fig. 101 (r ii 
adjustment for idling and starting and sh 
turns from its fully closed position. ^ 
turn the motor over. When the mote 
slightly to allow the njotor to warm up, 
motor stops, turn in the throttle set sere 
one turn to give more throttle opening, 
try turning the screw P in until the motor 
Now turn in the thumb screw R one nol 
each turn to get the full effect. Contini 
idling is obtained. This completes the 
ment; and when this is done in a thorough 
finished for that motor for all time. 

Speed Adjustment, All speed adju^r 
the ratchet-locked thumb screw M on top 
which is covered by the removable guai 



and if the motor stalls, give more fuel by again turning the screw M 
out a notch at a time. This adjustment should be followed through 
very carefully and slowly, and eadi adjustment tried out after it is 
made. Finally, if the faulty motor action cannot -be corrected in this 
manner, it is usually a sign that the choke tube is too lai^ and it 
should be replaced with a smaller one. 

Changing Choke Tvbes. Remove the two acom nuts Z; discon- 
nect the fuel line from the float chamber, after turning off the fuel; 
then the float chamber, groiip B complete, can be removed from the 
mixing chamber, group S, which is attached to the inlet manifold. 
This removal will expose the choke tube in the lower end of the mixing 
diamber, where it is held by the set screw C, located just below the 
idling adjustment. Loosen this, and the choke tube (marked L in 
Fig. 100) can be removed and replaced by another. The makers 
advise the purchase of two additional choke tubes with each carbu- 
retor, one larger and one smaller than that in the instrument. As a 
rule, the medium size of tube should be tnetl out first, but if this does 
not give perfect adjustment, the others may be tried out on the -road. 
INTien this change has been made and the two previously described 
adjustments are. complete, there is no further need for varying the 
carburetor, as once made, these settings take care of all temperature, 
alUtude, and other changes, including seasonal variations, 

Webber Automatic Carburetor. The Webber carburetor has 
been produced to meet the need for a very finelj- and carefully made 
instrument. It is an instrument of precision and is priced accord- 
ingly. Two models are made, namely, Model "C", which has a 
vertical outlet and water jacket; and Model "E", which has a" horizon- 
tal outlet and no water jacket and is therefore smaller and more com- 
pact. With these exceptions, the two are very similar in construction, 
as well as in adjustment For this reason only the Model "C" will 
be shown. This will be seen in Fig. 102, which shows a longitudinal 
section along the center line of the two chambers. It will be 
noted that this device has a concentric float 3? in which the 
spray nozzle 35 is located. The needle point 32 is controlled through 
the needle-point lever IS which works down onto it from above. 
The nozzle is placed in the center of the modified Venturi 
chamber 7, the top outlet of which consists of a series of 10 tapered 
boles. As the fuel mixed with the hot air entering through the air 


up the partly vaporized fuel. In this upper cylindrical vaporizing 
chunba St the throttle valve 18 of the simple butterfly type is 

TTie auxiliary air enters through the holes 60 below the dashpot 
chamber S in which the piston S is located. This is attached to the 
upper end of the auxiliary air-valve stem, its lower part having a 
conical extended shape so as to spread out the air. The dashpot 
]vevents fluttering while the downward movement of the air valve 
is re»sted by the spring 34. The tension of the spring'is adjustable 

ng. 103. Gitamal Vise of Wcbtwr Cuburetoc, Showinc Adiiutnunta 

by means of the milled thimble 28 and the locking plunger 30. The 
air-valve lever 11 b interconnected with the needle-valve lever IS, 
so that any movement which increases the air opening automatically 
increases the fuel flow also, and vice versa. 

Adjusting the Webber. There are two adjustments, aside from 
the setting of the air valve and the determination of the proper needle 
valve and its correctly proportioned spring. These are for low speed, 
or idling, and for high speed, or maximum power. Assuming that 
the carburetor has been installed correctly and the fuel turned, on., 

%tM. \^ V \^\t 

r>e sure that when the levt 
(handle operating Bowden wire) is move 
the lever F on the carburetor is pressed fo 

Low-Speed Adjustment. Move the 
to the rich position, open the throttle al 
the motor. Now move the lever on the st 
to the lean position and allow the motor 
warmed up. If it does not idle properly, t 
screw A up or down until it runs smoott 
against the stop screw Z>. The latter, aft 
should be fastened by setting up the clan 
purpose. This adjustment is for idling onl 

High-Speed Adjustment. The high-s 
by turning the screw B to the left or right 
block E in or out; moving it in gives less g 
moving it out gives more gasoline at high 
can be made with the motor standing and c 
to be the best position is reached ; but th 
ment should be made on a long hill. On thi 
at about 20 miles per hour, open the throttl 
at the top. Now go down the hill. After 
E out about ^ inch, try the hill a second ti 
torn at thp Qorno o,^^- « 



tbe point of maximum power; as tills point means maximum speed, 

Seiibilit.v, and acceleration. 

Starting Adjustment. The makers claim that it i» unnecessary 

vhm the proi)er adjustments have l>cen maric to wait for the motor 
towarm up before starting away; simply mo\'e the steer! ng-<:(ilunm 
control to the rich position, start the motor. aii<i drive olT, then, as the 
motor warms up, move this contn)l lever down toward the lean posi- 
tion, running normally with this as far down toward loan as it will go. 









SPfej "•^'"' 1 






li [dash pen 

■flft I PISTON 

▼^1 ' 


1 "isjtr I^JEl, 



r Air V.lve 

Except that some of these ailjusting s<Tews arc lorated differently, 
the adjustment of the Model "K" is the same an thiit of Mo<!el "('", 
as is also that of the Model "E H" a miKlificatiiin of the "K" wlapted 
particulariy to the Hupmobile. 

Rayfield Carburetor. The Uayficlil carburetor, Mcnlel "G", as 
shown in Fig. 11)4, is of the double-needle tyiw, with three air-inlet 
openings and an eccentric ilf>nt chamber. The latter is shown at the 
left, with fuel entering from heliiw through a strainer. Communi- 
cating directly with this float chamber Is the passage in which the 
low-speed nozzle (marked spray nozzle) Is situated ; this consists of a 
Jiollow member with the actual newUe point coming dmvn veT^]\«ji\\\>- 


from outside and above, simitar to C, Fig. 82. Commumcating with 
the float cliamber is a passage, or well, through which fuel flows across 
to the bottom of the high-speed well. In this passage is located a 
hollow metering-pin nozzle; and in the upper part of it is the meter- 
ing pin. The upper end, through which the fuel flows, is located in 
one end of the elongated vaporizing chaniber, while the upper auto- 
matic air valve has access to the top of it and furnishes the air supply. 
At the otlier end of the vaporizing chamber the idling needle is 
located, and directly beyond it is the constant air opening, a simple 
round hole communicating with the atmosphere. This end is short 
and close to the central portion of the chamber, which is approxi- 
mately cylindrical. The lower air valve is at the bottom.while the 
vertical connection to the inlet manifold and the butterfly throttle are 
at the top. The lower air valve and the upper automatic air valve are 
linked together so as to operate simultaneously. The movement of 
the upper automatic air valve downward actuates the metering pin, 
moving it downward; this tends to allow fuel to flow out around the 
pin. At the same time, the stem of this valve is connected at the 
bottom with a piston working in the dashpot which is filled with fuel* 
so that any sudden tendency for the air valve to open is checked by 
this <l;tshin)t. .At llie snnie tiiin'. tiiis nistcui cinninnnicutes with the 



Alwaj-s adjust the carburetor with this dash control down. The 
W-speed adjustment should be made first. To make this, close the 
throttle and let the dash control down, then close the nozzle needle 
V turning the low-speed adjustment, Fig. 105, to the left until the 
block U leaves contact with the cam M slightly. - Then turn to the 
rirfit about three full turns. Start tlie motor and allow it to run 
until warmed up, then push the dash control all the way down, retard 
the spark, close the throttle until the motor runs slowly without 
■'topping. Now make the final adjustment by turning the low-speed 
■^■rew to the left until the motor slows down. Next, turn to the right, 

high speew 


Fil. 103. Eitcmat View ot llayGrld Corburr-lur, Mudcl "C". .Sliuivinfi Adjuitinenti 

' one notch at a time, until the motor idles smoothly. If the motor 
does not throttle low enough, turn the stop-arm screw on the main 
throttle-valve shaft to the left until the motor does run at the mini- 
mum speed desired. 

High-Speed Adjustment. Advance the spark about one-quarter 
*ith the motor running, then open the throttle quickly. Should the 
motor back-fire, it indicates a lean mixture. Correct this by turning 
the high-speed adjusting sctcw, Fig. 105, to the right, about one notch 
■t a time, until the throttle can be opened quickly without back-firing. 
If loading, or choking, is experienced when the motor is running uw\« 



heavy load with the throttle wide open, it indicates too rich a mixture. 
This can be overcome b,\- turning the high-speetl adjiistment to the 
left. Adjustments made for high speed will not affect low speed. 
Low-speed adjustments must not be used to get s correct mixture 
at high speed. Both adjustments are positively locked. 

Changing Noxzles. "Never, under any circumstances, chai^S' 
nozzles in theModeis "G" and "L" carburetor," say the manufacturers. 
Neither should the float level be changed, as they say this is correctly 
set at the facttiry and should not be touched. For use with a pres- 
sure system, two pounds pressure is advised. The plugs S, 1, and X 

Note Lt^uid H/e' Dra'"< 
/Oamfoldb^SuCliCr of Mo/or 


s&id above on tbe subject of adjuatiag the "G" applies with equal 
^ force to the"L". 
^ AdjasUng Model "M". The Raj-field firm makes another model, 

knon'n as Model "M", which is similar to the Model 'T.", except 
that it has a side, or horizontal, outlet. It has the same two adjust- 
ments, made in the same way, but the shape of the carburetor locates 
these in a ditTerent place. The low-^speed adjusting screw is on the 
extreme top of the carburetor, and the high-speed adjusting screw 
is also on the top, but it is made accessible by removing the hot-air 
elbow from the main air \'alve. This model is fitted with a starting 
primer incorporated in the device itself and operated through the 
medium of a dash lever. In the sketch, Fig, lOG, which is self- 
CKplanatorj', the construction and operation of this are shown. When 
pressure feed is used, not more than one pound is recommended for 
Model "M". WTien the startingprimer is to be attached, the following 
method should be used: Locate the position on the dash desired for 
the push button and drill a |-inch hole at the proper angle. Attach 
the adjustment and run the tubing to the bracket on the carburetor, 
avoiding sharp bends. Cut off the tubing so it will extend beyond 
the bracket not more than \ inch. Remove the temporary wire 
from the carburetor, insert the tubing and secure permanently by 
tightening the clamp screw. Run the dash adjustment wire through 
the hole in the binding post on the eccentric lever. Then, with the 
push button down, place the eccentric arm in position so that the 
line on the eccentric just comes in contact with the adjusting screw. 
Tighten the screw in the binding post, cut off the surplus wire, and, 
without changing the position of the push button, make the carburetor 
adjustment, as previously described. 

Ball and Ball Carburetor. The Ball and Ball device has been 
developed by Frank H. and Frederick O. Ball and is named after 
them, but it is manufactured and sold by the Penherthy Injector 
Company. In all its forms, as used on a number of different cars, 
whether single or double, horizontal or vertical, it is a two-stage 
instrument. These two stages are called the primary and the 
secondary. As shown in Fig. 107, the primary stage corresponds to 
the usual simple air-valve carburetor. This consists of nozzle, or 
jet, 3, located in the fixed air passage, or Venturi, 2. In the passage 
above this, it receives its air for complete vaporization from the 

- I-.- vaiuuretor ad<l i 

nozzle and of the air supply T, wliid 

, './ /V nfcrrti^ I •,:,<■!•« 

fra^ tfap saaae bcuriKmuJI pftssuv- :' s^ 3w» t^ ftnaaay jn. 
If tte xlmndF W -occoKKiHid -up Ti» i^ v-idif? i^in-orV ic fiwii a v:^- 
that. TJisD aji^mnKiiiitc lirf nmLJima corrinc I'f 7^ ttuui: l^wnilr. 

irurc.. «se ■»\-«iiai: ctk- ibr li--flnfT njipt, -^y<h c.^ts- O'wJ i.ffirtf 

adjisz its tixaii tS*a tj> ihxi <rf the •;vimij\\ Thf TTr,>^' 

due ptvtjoftti bj -w+ikj b- is «^<«-^, i liivjitvV oir^ii^w^.ir, T>;i?v 

nh rtiiMaaEi~ foe i-:ajii'fli> sar> ntd i?"pr? iif c»j^ i-vcjiiiT:;:!!?:?- zhf HsW 
»») Ball JeiToe. Actt ia iih.Tii'flj ir; Fit. '. '.C, 

producrs renurkahir artv^efarxyD. TV.i> rt'^r.s;*:? --f liie -."iJ-^njprr -"" 
hail-in^ « anafifr aofti opt*? «>ii -. i: :< kv«*S a:;rti :- tSe .-^jbti- 
W IS, tht bonco «rf wikii ivromunk-ai^ with tr* Awt (-^MUi^Ser. 
utd is thus kcfft foQ fi Caroline. At the t>^. a ^nutli ht-iio : ' <.\«iniu- 
Duates wiih tbp manifotd abo'*"* llw xhn>nie, while : .' i* a:i .>|>e;'.i!\s 
to the atmospbere. aoJ ;? i* an opeairj; l<* ifce miwHi: (-hamher, 
^Vbra tbe throttle is nearly ck>?*e(l. ihe \~aouuiu in the mani^>kl 
ni^«s tbe plunj^er. and tbe space bek>*r it lilb *rtih ,ca~^^iiie. lii this 
pft^ilioo h is ready to act, Wlien the tht\>ttle is «^>eiH\l sih),i»>r.Ix . 
the vacuum b broken, and the plun£er(it\)|>s(^it^ own «-vi^t. fomiu: 
tbe gasoline up vbete it is swept into the mi\inf: I'haniK-T by 
the air entering throi^^ the passages :i and J^. This is ■vineaml as 
often as tbe throttle is suddenly openetl fmni a nearly' I'losvxl |>osition. 
Adjurtfnrntt. The primary stage must be atljusted as a whoto 
topve the best idling and slow speetls: thisivnsistsof ibeailjnstnKiii 
of the air-valve spring, the arrangement of the lK^t-«iir passage lendiixg 
(o it. or. if these prove insufficient, the changing of the priinarA' 
nozzle. The last change is opposetl by the makers. 

Beyond this, the only adjustment piissible li^-s >n the ht>t-ttir 
dtoike \alve whwA can be moveil or iiltetwl fnun tlie dash to give 
more or less bot air. The partial closing of t\m valve makes staniiig 
easier and helps tbe running of the motor until it gets warauxl up. 
but in nonnal nmoiiig iu manipulation has little etftvt. In gating 
farther than this, tbe only possibility lies in altering tlie design by 
^-aning tbe omnection between the two throttles, so the se*.vnd static 



cuts in sooner or later, but this might impair the usefulness of the 
instrument. The same is true if the secondary nozzle is changed. 
The device, then, is really lacking in adjustments in the ordinary 
sense, except for the initial setting of the primary-stage air valve. 

Newcomb Carburetor. The Newcomb carburetor is made by the 
Holtzer-Cabot Electric Company and is a constant vacuum tjpe 
having a single nozzle and an eccentric float chamber. It is a high- 
grade instrument and is used only on the highest-priced cars. As 


which* is of normal, or usual, construction, except for the regulating 
cap 77 on the top of the central opening above the float needle 85. 

Around the bottom edge of the plunger 69 a large number of 
holes of small size are drilled, and these are arranged to register with 
an equal number of relatively narrow air slots cut in the bottom of the 
plunger chamber walls. These distribute the fuel after it has passed 
up the central well, issued from the nozzle, and been drawn within 
the plunger. The plunger when at rest is seated on the collar 70y 
which is threaded into the bottom of the plunger chamber and is used 
as a means of adjustment, as will be explained later. This collar is so 
set as to raise the plunger slightly, thus opening the fuel nozzle without 
uncovering the air slots in the plunger chamber. In this way, the fuel 
port is given a lead with respect to the air ports, so that a rich mixture 
is delivered when the plunger is raised a little, as in starting or idling. 

When air is drawn through the carburetor by the motor suction, 
the plunger lifts in proportion to the amount of air entering. This 
lifts the needle and, at the same time, releases the exact amount of 
fuel needed to charge the ehtering air correctly and thoroughly. The 
higher the plunger is lifted, the greater the air and fuel openings. 
The effective areas of these air and fuel ports are so proportioned as 
to be correct at all positions. The slots in the plunger chamber walls 
being small, the jets of air coming through them have a high velocity, 
S3 that the fuel is atomized as it issues at these points. Any unatom- 
ized or unvaporized fuel is thrown against the heated walls of the 
vaporizing chamber, which are made greatest in area in this region. 
This produces a dry gas and high fuel economy. The gas passes 
around the outside of the plunger chamber, through the main throttle 
valve, and thence goes into the inlet manifold. 

Starting Device. The small pipe shown at 101 is a starting device 
and consists of a pipe connection from the lower part of the float 
chamber into the gas outlet passage above the throttle valve. When 
about to start, the throttle is thrown over to a position in which the 
opening of this pipe is included in the manifold above it. It is then 
susceptible to the partial vacuum existing there, and pure fuel in a 
very fine spray is drawn directly into the manifold. Under normal 
running conditions, its operation is negligible. 

The Dashpot. This device has a solid head to the plunger 69 
and also to the plunger chamber 68 in which it works. Between the 



two there is a considerable space, and, as the plunger is a fairly close 
fit in the chamber, this acts as a dashpot and retards the speed of tlie 
plunger when the motor is accelerating, or when tlie throttle is opened 
suddenly. By retarding the speed of the plunger, a richer mixture 
is obtained at the precise time when it is needed, in fact, demanded, 
by the motor. And yet when the plunger rises and stops rising, the 
mixture again becomes normal. This arrangement, therefore, does 
not need an extra rich setting in order to obtain good acceleration, 
for the engine can run on a lean mixture with a rapid pick-up. 

Mixture IndiccUing Pointer. The toji of the float chamber carries 
a name plate 8S on which a graduated arc varying from t to 5 is 
etched ; the 1 end being marked 
Ijoor, and the 9 end rich, as sliown 
in Fig. 109. On the top center 
ofthefloatchamber is a regulating 
cap 77. Fig. 108; attached to the 
top of it is the regulating pointer 
7tS', which traverses the arc shown 
and in this way indicates the 
quality of the mixture being 
formed with that setting. Thi.'* 
pointer, shown as straight, but 
ha^-ing two bends, from a hori- 
zontal to a vertical and back to a 
horizontal at the scale, ha^ a small 


AdjuttmeniJt. There are but two adjustments: the load- 
carrying adjustment controlled by the pointer 7S and cap 77 just 
described; and the idhng adjustment controlled by the regulating 
collar 70, mentioned previously, and shown in Fig. 108. Contrary to 
the usual method, the load-carrjing adjustment is made first, and the 
low-speed, or idling, adjustment is made last. To make the load- 
cuiying adjustment, set the throttle in the special starting position 
as descrihed, turn the regulating pointer to the rich position on the 
dial, then screw the slow-speed ring, or regulating collar, 70 as fa-r up 
it will go. This is the rich position of the ring for starting only. 
Flood the carburetor by means of the tickler 94 until gasoline appears 
.on top of the float chamber. Then start the motor and immediately 
move the throttle to a running position, othenvise the motor will stall. 
With the motor running nomially, move the regulating pointer 
78 to about 5 on the dial; this gives an average setting, but different 
points should be tried and the poor-mixture, or lean-mixture, side 
^uld be favored alwajs. To obtain the t>est setting, move the 
pomter half a point at a time, and try out the setting each time on 
the road. When the best setting has been found for some one condi- 
tion of motor speed and load, the mixture will be found correct under 
all conditions except idling. 

Idling and Low-Speed Adjustment. Now that the load-carry- 
ing adjustment has been made, the ring 70 which adjusts the mixture 
for idling should be unscrewed to weaken the mixture until the motor 
throttles evenly, without loading or popping when accelerated. 
Possibly the best combination of slow running and quick smooth 
accelenttion may call for a slightly richer mixture than that on which 
the motor idles best and slowest. After this setting has been made, 
to see if the ring is screwed up too far and is giving a richer mixture 
than is necessary, move the regulating pointer 78 slowly from the 
No. 5 point toward poor. If the motor speeds up, the mixture is 
too rich, and the ring 70 should be unscrewed until the motor idles 
correctly with the pointer in the position found to be correct for the 
load-carrying mixture. After the correct idling position has been 
found, all variadons for atmosphere, temperature, and fuel conditions 
should be made by changing the pointer only. 

Marvel CarburebM'. The Marvel carburetor. Model "E", 
shown in section in Fig. 110, is notable for using the exhaust g&se& 

lyiiiiancai float C ha 


These exhaust gases pass downward through an external cylin- 
drical passage and, after warming the Venturi and primary nozzle 
r^on, escape to the atmosphere. This gas is obtained by tapping 
into the exhaust manifold within a few inches of the last cylinder out- 
let (4 inches are recommended). As the motor demand rises beyond 
the ability of the primary nozzle, the inclined air valve is drawn 
toward the vertical position.and, as soon as it leaves the cylinder wall, 
the high-speed nozzle is uncovered and starts to contribute. The air. 
is supplied from the same air inlet, but it rises more directly. A 
throttle is placed in the air inlet to facilitate starting; closing this 
cuts off the air, so that a richer mixture is supplied. There is a 
damper, or throttle, F in the exhaust gas-inlet passage. It is inter- 
connected with the main throttle G in such a way that it is opened 
when the latter is closed and closed when the latter is opened. The 
idea is to furnish a great quantity of heat when the throttle is nearly 
closed, and to gradually diminish the supply as the throttle is 
opened and the motor warms up. 

Adjuatmenta. There are two adjustments: the gasoline adjust- 
ment //, so-called by the maker, and the air adjustment /. The gaso- 
line adjustment operates the primary nozzle. These preliminary 
adjustments can be made on the instrument as received by closing 
the gasoline needle valve // by turning it gently to the right until 
seated, then opening it by turning to the left ^ turn. The air- 
adjusting screw / should be turned until the end of the screw is about 
even with the edge of the spring ratchet J provided to hold it when 
set. After starting, close the throttle to produce a moderate speed. 
Then close the gasoline needle //a very little at a time until the motor 
runs smoothly. Allow the motor to get thoroughly warmed up, 
though, before making the final adjustment. 

Next, adjust the air valve. Turn the adjusting screw / to the left 
to back it out and release the air spring about one-eighth of a turn at 
a time until the motor begins to- slow down. This indicates that the 
screw is too loose, so turn back slowly, one-eighth of a turn at a time, 
until it runs smoothly again. Next, advance the spark two-thirds of 
its travel and open the throttle quickly. The motor should speed up 
promptly and quickly. If it hesitates or pops back a little more 
gasoline should be released at the needle valve H by turning it to 
the left a very little at a time. It may also be necessary to t\^\jea 


the air screw / a little more. Now, wait for the motor to settle down 
to this new adjustment, then open the throttle again quickly. Con- 
tinue this sudden throttle opening and subsequent adjustment until 
the point is readied where the motor will respond in a satisfactory 
manner to a sudden throttle opening. The highest economy is 
obtained hy turning the air screw to the left and the gasoline needle H 
to the right, dosing it as nearly as possible and still obtain the desired 

Fuel Supply. When the carburetor is fed by gravity, the bottom 
of the bowl should be at least eight inches below the bottom of the 
gasoline tank. When it is fed by pressure, one pound is sufficient, 
and two poimds should never be exceeded. 

The Marvel Carburetor Company also makes a Model "N". 
designed for Ford cars to which it can be attached without diange of 
manifold, levers, or otlier fittings. It is built on tlie same general 
plan as the Model "E" previously illustrated and described. 

Schebler Carburetors. The Schebler carburetor is one of the 
simplest complete carburetors made. In general, all Scheblers have 
a concentric float; a single needle valve, the position of which can 
be adjusted to suit varying needs; and an auxiliary air valve which is 



carburetor by means of tlie priming lever C, hglding this up about 
five seconds. Open the throttle one-third and start the motor, then 
dose the throttle slightly and retard the spark. Next, adjust the 
throttle-lever screw F and needle-valve adjusting screw B until the 
motor runs at the desired speed, smoothly and evenly on all cylinders. 
Then make the high-speed adjustment on the dials D and E. Turn 
the pointer on the dial D from 1 toward 3, about half way. Advance 
the spark and open the throttle so the roller on the track running 
below .the dials is in line with the first dial. If the motor back-fires, 
turn the indicator a little more toward 3, or, if the mixture is too rich, 
turn the indicator back toward / until it runs properly. Now open 

the throttle wide and make the adjustment on dial E for the high 
speed in the manner just completed on D for intermediate. As lean 
a mixture as the motor will stand is advised. 

This model is also>made with a dash-control air valve, as shown 
separately at the left of Fig. 111. Otherwise the carbui^tor and 
adjustment are exactly the same, except that where the directions 
previously given above have read A, those dealing with the dashboard 
connection should read Ai. As will be noted, the movement of this 
lever rotates a small gear which engages with a rack formed in the air- 
valve stem, so that movement of the lever gives the same result as 
turning the screw A, 

zfpLmat the «top C when the lever oc 
reiriitter* lean, or air. ThL- L^ the Drcier 

ConrUtif ef WhetUr and HrhebUr, Indianapclu, Iwiiama 

Unimm on the air-valve spring. Turning t 

or ckxrkwise, lifts the needle v»lv#» ^ — -^ 



present-day fueb and thr motor conditknsbettrr. AsF%. llSdiows, 
the Yentari tube b made much loofTr by an upward ejrttosion, whUt 
the needle has been changed so that it mox'vs downward to open; abo 
the needle-^-ahre adjustment has been remoxTd frooi the air \'al\Y 
and placed on the otha side. In addition, the neetlle v-ahT, or meter- 
ing (mu, is sutnoerged, that is. the pwnt b atw«\-$ below the fuel )e\'el: 
and a starting de\-ice, seen in the tonn of a dash rontrtd, pushes the 
metering pLn down and holds the auxiliar>' air \'alve dosed^in order 
to produce a vef>- lii^ mixture for starting. As to adjustments, the 
air-valve and dash amngetnents are abi>iit the same as on the "R". 
but the new fuel adjustment, by means of the milled Headed screw G. 

seen in the right-hand, or end, view, is managed in much the same way 
as the needle-valve adjustment on Model "L". 

Adjustment of Model " T"— Horizontal. The new Model "T", 
Fig. 114, has a horizontal outlet and is intended to be fastened 
directly to the.cylinders, doing away with the inlet manifold entirely. 
This necessitates more vaporizing space and changes the external 
appearance considerably. Float, fuel supply, and throttle are all the 
same; the metering pin is controlled by the operation of the air valve, 
as in the previous models, and the primary air opening is fixed but 
ia by-passed through the Venturi to the high-speed air opening. 
Tlie high-speed air valve opens over the Venturi, and the ui v% dtvvrc^ 

Fij?. 114. Schebler Carburetor. Model *'T". with 
Horizontal Outlet 



















begins to miss fire, then turn toward i 
until it is firing evenly. Make this last ad; 
set to idlp «+ ^^^'^ '^'^''•~ ' 



moving part, is drawn upward by the suction of the motor and comes 
back down onto its seat through its own weight when the suction is 
lessened. Id Fig. 115, the complete cart>uretor with the throttle 
open is shown at the right, and the vaporizing chamber only and with 
throttle closed is shown at the left; the float chamber is the same in 
both cases. Gasoline flows in through the strainer to the float 
chamber, thence to the dashpot, filling this and continuing to rise to 
a point about on a line with the top of the tapered metering pin, 
which corresponds to the usual needle valve. 

With the engine at Test, as shown by the left-hand figure, the 
upper end of the metering valve, which has a conical lower surface. 

rests upon the valve seat, thus closing the main air passage. Its 
lower end extends down into the gasoline in the dashpot. Through its 
center is an opening, known as the aspirating tube, into the low^r end 
of which extends (from below) the tapered metering pin. As soon as 
the motor starts, or is turned over, so that a partial vacuum is created 
in the mixing chamber, the metering valve is lifted to admit airpast the 
valve seat, asshown in the right-hand part of the figure. This vacuum 
is also communicated to the fuel chamber through the aspirating 
tube, drawing gasoline through it and up the central passage ; the latter 
is expanded in diameter near the top and is then flared out to a large 
coze at the point where the air entering through the vertical holes in 
the metering valve meets the gasoline and picks it up. T1[i&'^MXV<3«& 

._ ., una nil DV ITIcailSiif il ) 

to the inetcriiift pin in >ucli u wiiy tliaf , v 


increasing or decreasing the relative amount of gasoline admitted to 
the mixing chamber in response to the movement of the metering 
valve. This movement is produced by the rotation of the small gear 
A, which engages with a rack on the lower end of the tapered metering 
pin. This gear is rotated by means of a flexible-wire (Bowden) con- 
nection to the dash control. The limit of this motion, as well as the 
normal position of the gear, is governed by the setting of the adjusting, 
or stop, screw B, shown in the external view. Fig. 116. 

This screw can be turned either way; turning it to the right 
lowers the position of the metering pin, admitting more gasoline; 
and turning it to the left raises it so that less fuel is admitted. A 
wider range of adjustment than this stop screw affords can be had by 
releasing the clamp C of the pinion-shaft lever D and moving it around 
to a new position on the shaft. This- adjustment, however, is not 
recommended except for expert repair men. 

With the motor idling the adjustment should be made by moving 
the screw up and down, that is, out and in until the motor runs 
smoothly. This adjustment must be made with the dash control 
pushed all the way in. When this simple adjustment is made cor- 
rectly, the device is practically automatic from that time on. A stop 
screw E on the throttle lever is movable and affords the equivalent 
of a limited adjustment, for it can be set to give a smaller and smaller 
opening and thus slower and slower idling. It also has an influence 
on the maximum opening which influences the highest speed. 

Johnson Carburetor. The Johnson carburetor, of which a 
section through Model "D" is shown in Fig. 117, is one of the newer 
designs to be placed on the market. It is a simple form, with a con- 
centric type of float chamber A, above which is a simple cylindrical 
mixing chamber B containing the air-regulating device. It is sur- 
rounded by a hot-air jacket C, which warms the mixing chamber and 
furnishes the primary air supply. • This is composed of the strangle 
tube D and air controlling sleeve E, with a lift plate F suspended 
from this sleeve in the strangle tube. 

Operation, Gasoline enters the float chamber from above, in 
the usual way. It enters the spray nozzle through the cross-hole G, 
then rises inside this and passes the tip of the needle H, where it con- 
tinues out through the nozzle point into the lower part of the mixing 
chamber. The fuel issues as a fine spray into the strangle tube D y 


which is conical in shape. In the mbdng chamber is a sliding brass 
sleeve E, which moves up and down according to the engine suction 
and carries the lift plate F which is just above the outlet from the 
spraying nozzle. Warm air enters the air inlet / and finds it3 way 
around the chamber C, some 
of it reaching the passage J 
below the lift plate and stran- 
gle tube. Here it picks up the 
fuel from the nozzle and im- 
pinges it against the lift plate 
to break it up into finer parti- 
cles. In addition, the rising 
air and fuel raise the plate and 
with it the sleeve E, allowing 
more air to enter around the 
bottom of the sleeve. By this 
arrangement, the current of air 
is divided and forms both the 
primary and the auxiliary cur- 
rents. The latter current is 
varied to suit the engine de- 
mands by the rising and falling 
of the sleeve. This move- 
ment of the sleeve automat- 
icall\' proportions the air and 
gas to the demand, for, in 
rising, the lift plate is drawn 
away from the nozzle tip, and 
morefuelisallowed toflowout. 
On top of the strangle 
tube rests a flat choker plate 
A', which is capable of being 
turned around. There are 
holes in this to correspond with the holes in the strangle tube through 
which the primary air passes down to the lower side. In rising again, 
it picks up the fuel spray. A lever L extends through the outside of 
the carburetor and is connected up to the dash control. This lever 
controls the choker plate which can be moved around to cover or 


uncover the air holes and give more or less primary air as the device 
needs it. Thus, the low-speed screw M, the needle valve, and the 
stop screw N on the throttle shaft constitute the adjustments. 

Adjusting the Johnson, The function of the low-speed screw is 
to admit or to cut off the small amount of air supply to the upper 
part of the mixing chamber as the motor demands; this screw is to be 
adjusted only with a closed throttle, retarded spark, and the motor 
idling. The motor should be hot. This is ^n idling adjustment, 
designed to supply additional air through the opening 0, the need for 
which is caused by the sleeve E being in its bottom position and thus 
cutting off the supply, which is available later when the sleeve has 
risen and in so doing has formed the annular air passage. 

The spray needle //, adjusted by the external handle, takes care 
of all other throttle positions and speeds by admitting -more or less 
fuel. To adjust it, turn the low-speed screw and spray needle to 
their seats and set the throttle-lever stop screw to approximate the 
correct closed position. Open the spray needle one and one-half 
turns. Start the motor, and when it has warmed up, place the spark 
lever in the fully retarded position; then open the throttle quickly, 
and if the motor does not back-fire, the mixture is slightly rich and 
the spray needle should be closed by turning to the right about one- 
eighth of a turn. Again open the throttle quickly and repeat until the 
motor does back-fire; this will determine a lean mixture. Open the 
needle slightly to correct the mixture, which will give the correct 
adjustment on high and intermediate speed. Adjust the throttle 
stop screw until the desired idling speed, or about 240 r.p.m., is secured. 
If the motor does not fire continuously and run smoothly, the low- 
speed mixture is too rich and is corrected by backing out the low-speed 
screw M until sufficient air is admitted for smooth even firing. Then 
lock it with the lock nut. If this last adjustment has increased the 
speed of the motor, restore the idling speed by unscrewing the throttle 
stop screw N slightly. If necessary, reset the low-speed screw, as 
both of these have to be adjusted in combination. 

Dash Control, This controls the choker plate, which acts as a 
choke to the nozzle by reducing the supply of primary air. After 
the motor has been warmed up, this should be in the wide-open 
position. The position for a cold motor, approximating the closed 
position, will be determined by experience. It is recommeud^ \.Vk^\. 



the motor be choked, that is, the dash control set in the closed position, 
when stopping. This provides a rich charge for starting. As will 
lie seen from this, the choker plate, with its dash control, is primarily 
a starthig device. 

Other Models. This carburetor is made in other models, notably 
a small one for the Ford car; the essential difference in this being the 
location of the low-speed screw on top, as it has a horizontal outlet 
on one side and the warm air inlet on the other. Another large size 
for eight-r\linder models has a special accelerating device consisting 
of a fuel plunger operated from the throttle. Still another model is a 
fixed-needle type in which 
the nozzle is calibrated for 
the motor. The adjust- 
ment is practically the 
same for all these. 

Carter Carburetor. 

The Carter carburetor is 

a multiple-jet device in 

which, at slow or idling 

' i^peed. but one jet is fur- 


and rises vertically along it. Around the upper part of the standpipe 
is a flaring conical tube, the top of which is closed by a damper. Air 
enters here and is drawn downward, its amount being controlled by the 
damper. At the left will be seen the supplementary air valve, a third 
source of air; this air is also drawn downward, and the amount is 
adjustable. From this it can be seen that the primary air and the fuel 
from the first few jets come upward, while the secondary air and the fuel 
bom the additional jets go downward, and that the supplementary air 
rushes in at an angle where these two meet at the bottom of the 
U-shaped vaporizing chamber. This produces a constant state of 
turbulence around the standpipe, which facilitates breaking up and 
vaporizing the fuel. The fuel passes a butterfly throttle in its 
passage to the inlet manifold. 

For easy starting, a tube (marked anti-strangling tube in the cut) 
is by-passed around the vaporizing chamber, taking its fuel directly 
from the well at the left of the float chamber and furnishing it 
directly into the outlet pipe above the throttle. In starting and 
idling on the lowest jet, or hole, of the stdndpipe, the fuel is drawn 
almost directly from the float chamber. For this reason an unusually 
accurate float arrangement is necessary, and this is provided by the 
metal ball float and the needle arrangement with its ball and spring 
shock absorber. The latter eliminates any possibility of jamming 
and gives accurate control of the fuel level. The action of the device 
is very simple, the engine suction drawing the fuel higher and higher 
in the standpipe as the suction increases, while the same suction draws 
t^ten the intermediate air valve as soon as the required supply exceeds 
the capacity of the main air intake. The high-speed air inlet, oper- 
ated by the damper, is thrown into action from the steering post or 
dash at the will of the operator. 

Adjuring the Carter. By reference to Fig. 118, and also to 
Fig. 1 19, which shows the exterior of the device, the method of adjust- 
ing will be made plain. First set the high-speed adjustment with the 
lever in a vertical position; then turn the knurled button marked low- 
speeA adjustment down, or to the right, as far as it will go; neict back 
it off and turn it to the left three-quarters of a turn. Turn the 
knurled valve ring. marked intermediate-speed adjustment to the 
point where the valve seats lightly, then turn the valve down, or 
to the ri^t, from eight to ten notches to increase the spnng temvoTv. 




Puil the easy-starting lever, connected with the dash, forward to the 
jmsition shown in Fig. 119, advance the spark a very little, close 
the throttle, and start the engine. 

Through the medium of the anti-strangling tube, thia will 
furnish rich mixture (almost pure fuel) to tlie inlet manifold and 
result in instantaneous starting. Immediately reverse the easy- ■ 
starting lever which controls the flow of fuel and open the main 
throttle slightly. By means of the two screws A A on either side 
of the throttle lever, set the throttle valve where it gives the desired 
engine speed when idling. 
^^tOj^m^m W^^ ^^"''^ ^^^ low-speed ad- 


^^^^L notch at a time, until the 
^^^^^K engine slows down, noting 
^^^^H each setting. Now move 
^^^^^ it in the opposite direc- 
^H tion. one notch at a time, 
. until the engine again 
a^ slows down. Then move 
O the adjustment to a point 





temperatures, or when the engine is cold, this control should be moved 
toward the closed position, so as to cut off air and make a richer mix- 
ture. At high temperatures and with a warm engine, the best results 
are obtained with the control wide open. This is the only adjust- 
ment which should be varied for weather or temperature variations. 
Packard Carburetor. The carburetor used on the Packard 
twin-six (twelve-cylinder) cars is shown in section in Fig. 120. The 
inlet manifold, or rather the pipe which leads in both directions to the 

manifold proper, is seen at the top at A. It will be noted that this is 
water-jacketed, the water space being at the top. The float arrange- 
ment is of the usual type, with a metal float which supplies fuel to a 
small well B at the base of the single-sp^a^' tube C. This has a flared 
end located in the center of the Venturi. When the air from the air 
bom D passes the air shutter E, it picks up the fuel and carries it up 
into the vaporizing chamber F. The primary air shutter is normally 
open but not in use. It is operated by a hand wheel on the control 
board which also operates the auxiliary air valve G. By tmnvu^ t.\v\& 


dear over to the position marked choke, the air intake is closed, and a 
rich mixture is drawn in tor starting. After that, the hand wheel 
should be set back toward the position marked air which opens the 

The auxiliary air valve is controlled by the springs H and I. 
These are adjusted so that the valve opens very slightly at low speed, 
but more and more as the speed, and consequently the suction, 
increases. The air enters around the outside of the ^'enturi, communi- 
cating with the mixture only above the top of the latter where the 
real vaporizing chamber commences. The tension of the springs is 
\-aried by means of the adjusting nuts at the top and by the adjusting 
CB-tnaJ, The cams are connected up to the air-valve hand wheel which 
is turned toward jias to provide a richer mixture and toward air for a 
leaner mixture. If the wheel is turned too far toward air, spitting 
back may result; and if it is turned too far toward gas, the result may 
bo irregular running and overheating. The throttle K is of the but- 
terfly tvpe and regulates the quantity of mixture allowed to pass out, 
not its quahty. An adjustable stop holds this valve open slightly 
and allows a small amount of mixture to pass, even when the hand 
throttle is entirely closed. This minimum amount is for slowest 
running, or itilinif, only. To increase it, loosen the check nut /.. and 



ir. This air reaches the passage L, whence a portion is 
iward around the outside of the Veoturi /, through the 
ind around the hottom of the tube, then upward. There 
h the fuel spray, vaporizes it, and carries it up into the 
zing chamber N, where additional air comes in from L, 

.ture passes on up, through the throttle valve 0, into the 

tver P attached to the throttle valve shaft is hung the 
■od Q, by means of which it is attached at its lower end to 
^ This works up and down in the cliamber 8. Its lower 
rell, T is full of fuel and communicates through passage V 
tl F and the nozzle H. When the throttle is opened, the 
orced into the gasoline in the carburetor bowl, and fuel 
ed through the hole (? up to the nozzle H. VHum ii)Qft 



throttle ia opened quickly, this acts to supply the needed fuel. When 
the throttle is opened siowly, the plunger has practically no effect. 
This plunger has an influence on starting, as will be explained. 

Adjiiatvients. Carburetors are factory set «nd should need no 
adjustment ordinarily, but for different atmospheric conditions a 
slight change in the air-valve spring may be needed. In the exterior 
view, Fig. 122, this is altered by turning the screw V. In case the 
carburetor reall,\' needs adjustment, proceed as follows: Open the 
throttle lever on the steering wheel about two inches, place the spark 
in the driving range and start the motor; run it until the water jacket 


be at the extreme left when this adjustment 13 made. With the spark 
and throttle levers in this same position, adjust the air valve screw V 
again to the highest motor speed. Open the throttle until the shutter 
attached to the right-hand end of the throttle shaft just covers the slot 
in the carburetor body (the other side of the carburetor is not shown 
in either view). Then adjust the screw X to the point which pro- 
duces the highest engine speed or to a point where the engine slows 
down slightly from a lean mixture. This screw also works clockwise 
to give a richer mixture and counter-clockwise for a leaner one. 
During very cold weather, it will be found advisable to turn this screw 
farther in a clockwise direction to give a slightly richer mixture. 

The rod Q from throttle arm P to the fuel plunger is adjusted 
closely at the factory and should need no change unless the carbu- 
retor is disassembled. When reassembling, the rod should be ad- 
justed 30 that its upper end is flush with the upper face of the arm P. 
ftTien the carburetor has been used for a long time, there may be slight 
wear at the pomt of the inlet or where the float needle D, Fig. 121, 
rests on its seat. If this should occur, the height of the fuel in the 
carburetor bowl will rise. To* determine whether the float is set 
properly, remove the carburetor from, the engine and the bowl from 
the carburetor. Then measure the distance from the upper surface 
of the float to the metal surface above it, as indicated at Y to Z. 
This is measured best with the carburetor inverted and should be 
exactly J inch. If more, or less, the setting may be corrected by 
sli^tly bending the arm to which the float is attached. 

Starting, In cold weather, when the engine will not start imme- 
diately, it is not advisable to continue cranking the engine over and 
over. Instead, open and close the throttle rather quickly once or 
twice, no more, with the throttle lever on the steermg wheel or foot 
accelerator. This action raises and lowers the throttle pump at- 
tached to the throttle-shaft arm, as previously explained, thus raising 
the level of the fuel in the float chamber so that it is more easily 
drawn up. If pumped more than once or twice, too much fuel will 
he forced up, and this is just as bad as too little. 

Oxygenerator Vaporizing Device. The oxygenerator is a new 
device designed to assist vaporization and, in so doing, economize on 
fuel. It is not in itself a carburetor but is used with a carburetor — 
any standard make — to generate, as its name would iadica'te, ox'^^il 



which vaporizes the liquid fuel more readily than atmospheric air. 
It consists, as Fig. 123 shows, of a box-like generator which is fastened 
to the top of the exhaust manifold by means of chains; of a coil of 
copper tubing to go around the exhaust pipe; and of an extension of 
this piping with the proper number of screw ends to be tapped into the 
branches of the inlet manifold. The figure shows three injectors 
for a three-way manifold; when tlie connection is made direct to 



the steam is superheated. This process of superheating develops 
con^derable pressure, so that the steam particles are shot into the 
mixture, aiding materially in breaking it up, and in this way complet- 
ing vaporization. In addition, this superheating results, to a certain 
extent, in the decomposition of the water into its elements, oxygen 
and hydrogen, both of which are highly combustible. The addition 
of these greatly facilitates the vaporization and combustion of the fuel. 
The process is cumulative; the faster the engine runs, the more 
heat there is available for boiling the water and superheating the 

Fi«, 124. Diacmmniatia Skclcb, Showinc Acliop of Oiygfnermtor 

steam. When slowing down and stopping, the valves take care of any 
reaction in the other direction. The process has a number of features 
which distinguish it, as, for instance, boiling purifies the water so that 
all sedimeot is left in this container. The clean burning of the fuel 
is said to eliminate the usual carbon deposits, and the missing and 
back-firing, as well as pre-ignition which results from carbon. In a 
few certain instances, it is said to have increased the mileage per 
galloD of fuel on these cars : Marmon, 24 per cent with no carbon ; 
Oakland, 24 per cent with no appreciable carbon in 4000 miles; 
Bnidc, 27 percent with no carbon in4000 miles; Speedwell, 31 percent 
with PO (wrbpn }n 6000 miles; Case, Hudson, and CadUVac, eajtii ^ 



per cent with no carbon. In addition, it is said to have improved the 
acceleration, speed, and power in all cases. 

Adjustments. There are no adjustments beyond the valves 
/, 2, and 3. It is recommended that valve S should not be touched. 
The only reason for varying 2 is to lower the pressure at which the 
valve pops, or opens, but the makers recommend that this be kept 
high. ^'aIve 1 is adjusted only to increase or decrease the vacuum 
within the tank. It is said one turn of the adjusting screw at the top 
will create from two to twenty-one inches of vacuum within, so it 
can he seen that this valve needs very little adjusting. 


Need for Heavy Fuel Carburetors. As has been mentioned 
several times previously, and explained elsewhere in detail, the 
lighter, more volatile grades of 
gasoline are not available in suf- 
ficient quantities to supply the 
present demand. Consequently, 
the fuel now carries a consider- 
' quantity of what was for^ 



to 8 per cent; save almost one-half of the engine lubricant; give less 
spark-plug trouble and less carbonizing; and give a greater mileage 
to the gallon. In doing these things, it has these deficiencies: 
requires the use of gasoline for starting; and necessitates a material 
reduction in compression pressures. 

As shown in Fig. 125 and applied to a motor in Fig. 126, the 
float chamber is standard. Exhaust gases enter at F, passing around 
the two vaporizing tubes R and L, and out at S. The primary air 
enters at /, is heated by the exhaust, and at low speeds flows up 
through the mixer tube R. This is supplied by the nozzle Q and, by 
noting the constructions at its upper end, it will be seen that this 
works only until the but- 
terfly valve B is opened, 
when nozzle K comes 
into action. The tube L 
is corrugated to get the 
greatest possible heated 
surface for its length. 
Fig. 126 shows its appli- 
cation to a motor, K 
being the exhaust con- 
nection to the kerosene 
carburetor A, B the 
gasoline vaporizer for 
starting, and C and D 
its connection into the 
inlet manifold. Lever F on the dash controls the vaporizer, which 
is shut off after starting. The usual throttle connection to lever // 
has another connection to lever ./ which operates an exhaust throttle, 
the idea being to deflect all the gases to the kerosene carburetor at 
low speeds, but as the throttle is opened and tlie engine speeds up, 
producing more heat, less exhaust gas goes to the vaporizer. In 
testing out this device, the maker found three necessities, namely: 
shortest possible kerosene manifold; shortest possible exhaust heating- 
pipe connection A'; and shortest possible gasoline connecting tube C. 

Fore^ Kerosene Carburetors. A large number of firms in 
different ports of the world have worked on this problem of kerosene 
vapoiization. In Germany, the following have done w, «.tv& vq. 

Fie. I2S. Method dI Applyina H< 

W Holiey K( 
lihsiist ripii 


solving this each has been obliged to develop his own vaporizer: 
Daimler; Swiderski; Maurer; Adler; Sleipner (boats mostly); Deutz; 
Banki; Neckarsulmer (motorcycle); Koerting (fuel injection); Kam- 
per; Diesel (fuel injection); Capitaine (boats mostly); Gardner; 
Dufaux {Swiss motorcj'cle) ; and others. Space prevents a descrip- 
tion of these, the Hst being given simply to show that kerosene as a 
fuel has attracted wide attention. 

In France the same is true; the Aster device, for instance, having 
been so very successful that it is now made under license in both 
England and Germany, 

In England the Binks, with two jets, is designed to use 20 per 
cent gasoline and 80 per cent kerosene after starting. The Hamilton 
Bi-fuel has two float chambers, two nozzles, and other duplicate 
features. Tliis is designed for a 44 gasoline (petrol) and 50 kerosene 
(paraffin) mixture; on such a mixture, a test of a bus engine showed 
equal (rate<!) power at 890 r.p,m,; 1 horsepower more at 1050; almost 
3 more at 1275 ; and iit its highest speed 1375 r.p.m., Shorsepower more, 
maximum output. The Kellaway has two fuel leads, but these use a 
common jet. The Morris uses forced feed with a constant air pressure 
of 4 pounds per square inch on the fuel tank; this is supposed to mini- 
tifuel lliiw. and thu.'-, as poiiited out in thedet^ 



builders of tractor, marine, and stationary engines have been more 
or less successful in vaporizing kerosene so as to use it advantageously. 
Master Carburetor. The Master device, previously shown and 
described, was designed primarily for the extra heavy fueb, or the 
residuum in the distilling process called distillate, which is heavier 
than kerosene' and has heretofore been considered a waste product. 
The Master has utilized this successfully in actual service 
for more than four years. In addition, it will handle kerosene, 
alcohol, and other heavy fuels, as well as mixtures of all these with 
one another and with gasoline. 

Cli/, NrM r«Tk 

Senrab Carburetor. In the Senrab device, shown in Fig. 127, 
the vaporization of kerosene and heavy fuels is effected without the 
use of multiple nozzles; for a single simple needle and nozzle with a 
series of small radial holes as a fuel outlet does the trick. In the 
figure, the fuel enters a float chamber A of ordinary design from 
below, through a simple removable strainer. It is then carried through 
a small bole B in the side of the float chamber nearest the vaporizing 
diamber into the vertical well C. At the bottom of the well is 
a borisontal passage D whieh communicates with the bottom q1!^3ia 

.... «■ «^V<1 

13 an auxiliary air valv 
is sufficient to lift it. This admits i 
inlet pipe /, as it affords a larger and n 
pletes the vaporization, and the mixti: 
the butterfly type M into the manifold 

Additional heat is furnished to the 
by exhaust gases taken in through the 
vaporizing chamber and nozzle, then a 
out at 0. This is not heated air, but 
temperature, obtained by tapping int 
three-way valve P is set at the turn in th 
kerosene passes from the horizontal pass 
nozzle lube E. Through the medium of 
ing purposes is allowed to enter from a sn 
provided for this purpose. The valve c; 
gasoline only, kerosene only, or a mixt 
driver can vary his fuel to suit himself, \ 

Adjustments. The hot-air throttle h 
dash or steering post and can be used like 
tion. When a richer mixture is needed, i 
position as desired; and for a leaner posii 
open position a« ^'*''' — ' ""' 


to the high speed. Run the en^e as fast as possible, openiiig the 
needle valve gradually until the mATimnm point is reached. Then 
lock the needle. 

Features, As will be noted, the throttle chamber K and the 
entire upper construction is made curcuUr in form where it joins the 
body and is held in place by simple machine screws, lliis construc- 
tion allows the upper part to be set in any desired way. By removing 
the screws, it can be turned one or more screw boles. Similarly, 
it will be noted that the hot-air inlet pipe, complete with its throttle, is 
held in place hy the exhaust connection N, which is screwed into the 
carburetor hody. By loosening this, the hot-air group can be turned 
around to any desired position, or if more heat is needed, a longer 
member N allows a different hot-air connection / to be used with more 
air apace. So, too, the three-way valve P b held on by screws which 
can be taken out readily when it is necessary to inspect or clean it 
or turn it to a different position. 

Bennett Carburetor. The Bennett device. Type "C" of which is 
shown in section in Fig. 128, is intended for kerosene, alcohol, dis- 
tillates, or other heavy fuels, but by a simple change of the adjust- 
ments It can be used for gasoline. For alcohol, however, the makers 
provide a special float, the carburetor remaining the same otherwise. 
It has two needle valves; one projecting downward from the top of 
the device A, called the slow-speed needle; and the other, projecting 
upward from the bottom B, called the high-speed needle. The 
primary air for both enters at C, passes around the exhaust 
heating pipe D, and enters from helow. It rises around the lower 
needle and fuel passage into the chamber E, where the fuel is picked 
up and carried up into the main vaporizing chamber F. From here 
it passes up into the passage G, where additional air comes in from 
the air valve H, after passing the air throttle /. This dilutes the 
mixture and complete^ vaporization, and the mixture passes the main 
throttle J into the manifold, or engine. 

The fuel enters the float chamber A', in which the float is indi- 
cated, and passes from this through the horizontal opening L to the 
needles. As there is hot air in the passage just below the opening, 
and exhaust gases in the passage just above it, it is subjected to a 
considerable warming effect. In the center at the bottom, a recess 
forms a dashpot for the lower end of the shaft M, which is connected 



to the air valve H at its upper end; Urn prevents nqxd i 
or fluttering, of this valve when there is a sudden opening of the 
throttle after running at alow speeds The extra suction created by 
the 3udden opening* of the throttle tends to jerk the auxiliary air 



r i 

g • V, 1 p 

W H ''■--^^ f 













1 ^/ 




r I 

& ^j\ 





\^^ I 







the medium of the valve attached to the bottom of the small dash- 
pot and the {dunger P which surrounds the bottom of the high-speed 
needle B. An additional feature of the device is an air cleaner Q, 
which is shown at the left in the diagram, Fig. 129. Its function 
is to clean all dust out of the entering air when the carburetor is 
used on a tractor or other unit which must work in the midst of con- 
siderable dust. As this dust is known to filter slowly but surely 
through the carburetor and, in time, reach the pistons, valves, rings, 
and bearings, where it does considerable damage, the utility of this 
simple auxiliary device, which has no moving parts, is evident. 

InataUaiion. Whenever it is possible to use the air cleaner, 
install the carburetor with the hood of the air intake facing away from 

B«anett C«fbufelor 

the fan so as to prevent dirt from being blown into it. Connect the 
exhaust manifold to the carburetor, using the three-way valve or 
damper in such a way that the amount of gas can be regulated. When- 
ever possible the exhaust connection should enter the larger end, 
because the cored passage for heating the primary air is there. Screw 
an elbow in at the other end, and, if required, a short piece of pipe, 
to carry the used exhaust gases away from the carburetor. Connect 
the water jet near the bottom with the water jacket or a small 
auxiliary water tank. This water jet and its regulating needle can be 
moved to any desired position by means of the large nut R. The 
needle is connected to the dash so as to be operated by the driver. 
Two fud tanks are needed, one for gasoline to be used tot s^l^^o^, 


and ihe other for kerosene to be used in regular running; they should 
be connected to the float chamber at the bottom by means of a three- 
way valve or a siamesed pipe, with a shut-off cock in each line above 
the T-connection, 

Adjustment. There are but two adjustments, so-called: the 
high-speed fuel needle for full load; and the slow-speed fuel needle for 
slow speeds and idling. Both are made by knurled nuts, which are 
turned clockwise to close and counter-clockwise to open. In the 
process of adjusting, close the exhaust damper S, so as to throw the 
exhaust gases through the carburetor and furnish the needed heat. 
Then close the air-choke valve /, to make a rich mixture for starting 
purposes. Before turning on the gasoline, open the high-speed needle 
B about two turns. Then start the motor and immediately open the 
air choke valve /. If it fires unevenly after running a little while, 
close the slow-speed needle ,1 by turning the knurled nut T to the 
right, one notch at artime, until the motor fires and runs evenly when 
throttled down to the slowest speed. If the motor hesitates and stops 
when the air choke xaWe \a opened, open the slow-speed adjustment, 
one notch at a time, until the point is reached at which the motor 
will Just run and fire evenly when throttled down. 

RegulMte the high-speed needle until the motor will respond when 


should be opened. This pre-ignition can be detected as a sharp 
metallic knock in the cylinder. Only enough water should be used to 
stop the knock; the carburetor should not be flooded with it. The cap 
at the bottom, or inlet, of the air cleaner Q should be kept tight. The 
air cleaner should be emptied once a day, but it should not be 
removed white the engine is nmning. 

"H & N" Duplex Carburetor. The "H & N" carburetor is 
called duplex because it is designed and intended to utilize both 
gasoline and kerosene with equal efficiency. In this respect, it differs 

from the usual kerosene carburetor which uses gasoline for starting 
purposes only, because it often requires a change of adjustments 
b^ore the best results are obtained when changing from kerosene 
to gasoline. A section through the "duplex" is shown in Fig. 130. 
In this the float chamber is eccentric and in two parts M for the two 
fuels. These pass to the nozzle L and to the needle, or metering 
pin, D, through the horizontal passage R. The fuel to be used is 
detenniiied through the selectmg plug N, controlled by the shift 



By inspecting this plug carefully, however, it will be noted that 
gasoline only ia intended to pass through the horizontal pipe H, as 
the kerosene passes out through another passage S, then upward past 
a special kerosene metering needle T into the annular passjige U. 
From this, a vertical annular passage [' of ver>- small dimensions 
leads upward and then inward to the surface of the Venturi //, where 
a series of very fine holes H' spray the kerosene into the vaporizing 
zone. It will be noted that in passing from the annular passage U 
and the smaller passage V up to the spraying holes H', the kerosene 
is subjected to exhaust heat, the relative heating surface being great 
compared with the small surface film of fuel. The exhaust- 
heating passage is constructed so that the gases enterir^ the lower 
pa.ssage J heat the inside surfaces of the kerosene passage U first, 
then turn and, in passing through the outer or upper passage /, heat 
the outside surface. In this way the maximum amount of heat is 

The primary air enters the bottom opening P, rises around the 
nozzle L, picks up the fuel and partly vaporizes it in the Venturi //. 
then rises into the passage or space A' above this. Here additional 
air enters through the auxiliary air passage C, the area of which is 
.'emed by the movement of the compensating air valve F towanl 



large carburetors, this can be ascertained by inserting a bent piece of 
wire through one of the air ports and raising the valve to its highest 
point with it; then releasing it and noting whether it sticks or drops 
down again to its nonnal position. If the valve sticks, the carburetor 
will not operate properly. In small sizes, half the outer casing A, 
Fig. 131, can be removed to determine this point, which is important. 
Bolt the exhaust heat by-pass to the flange of the exhaust mani- 
fold, as the figure shows; insert the flexible tubing and fasten it by 
means of a piece of wire inserted through holes, which should be 
drilled for that purpose. A mixture of glycerine and lithai^, or 
graphite, can be used to make a tight joint. Provide a two^allon 
tank for gasoline and a large tank for kerosene. Run a pipe from 

Ha- 131. Eiterod View ol "H Knd N" Duplei Ckibuntor, Sbowioc AdiuatnieotB 

the kerosene tank to the union below the kerosene compartment in 
the carburetor and a similar pipe from the gasoline tank to the gaso- 
line compartment. Make all joints leak'proof with red lead or shellac. 

Siarting. Close the throttle lever and start on gasoline. The 
fuel-shift lever in the sketch is shown for kerosene fuel; for starting, 
it should be thrown to the opposite position. Let the device run for a 
few minutes until it becomes heated. The fuel jet control, lever 
BB at the bottom of the carburetor, which controls the position of the 
nozzle L, is set closed at the factory, so open this a half turn before 
trying to start. 

AdjuatTTienis. With the lever in this positioii, an extremely ' 
ridi mixture will be formed, so turn the lever back in the direction of 
doeed until the best running at slow speed results. J\»t \)^*3W 



making the shift from gasoline to kerosene, open the jet sli^tly; 
after shifting; to kerosene shift back, but not necessarily to the same 
amount. For high speed, screw the vacuum relating screw B all 
the way in, a<lvaiice the spark, and open the throttle wide; if the carbu- 
retttr buck-fires, unscrew the needle B a very little at a time until the 
back-firing ceases, or until the motor runs satisfactorily. Lock with 
the knurled nut after each 
adjustment. Do not at- 
tempt to make high-speed 
adjustments with the lever 
BB. Do not stop the 
motor when running on 
kerosene; always shift to ' 
gasoline in order to insure 
a gasoline mixture, which 
means easy starting the 
next time. 

Deppe GasQenerator. 
Althougli not called a car- 
buretor by its maker, the 
:enerator re- 


kerosene, naphtha, etc., and mixtures of these; fixed metering adjust- 
ment which is not affected by altitude, temperature, or location; easy 
starting; less vibration of en^ne; and others. 

Id Fig. 132, the fuel enters the fioat chamber A from below and 
passes through a horizontal passage B from which the two nozzles 
lead upward. The low-speed nozzle C draws its heated air through 
the primary intake D and mingles with this in the modified Yenturi E. 
When the engine demands more fuel, it is supplied by the high-speed 
nozzle F, which gets its air from the auxiliary air valve G; this air and 
fuel mixture combine with the other in the chamber H, just above 
the Venturi and just below tlie center-opening throttle /. Up to 
this point it is not radically different from the average two-jet car- 
buretor with the auxiliary air valve. 

However, in the chamber just above this a mechanical atomizer, 
or rotating mixer on ball bearings J, is inserted. The idea is to com- 
bine the air and fuel particles more intimately through the rotation 
of this mixer within the zone of vaporization. The actual vaporizing 
chamber K is next above this. It is an annular passage around the 
highly heated exhaust gas chamber L, but inside of the outer exhaust 
chamber. This insures the absolute completion of the gasification 
started in other chambers, so that the mixture passing into the gasi- 
fication chamber M at the top and thence into the inlet manifolds 
and cylinders is sure to be a pure dry gas. 

Starting. To assist in starting, the primary-air passage is fitted 
with a choke valve of the butterfly tj^pe, which closes off this passage 
entirely so as to produce a rich mixture. -Across the middle of the 
lower vaporizing chamber H, an electric resistance wire or heating 
coil is strung. The coil is connected to the starting battery. The 
connection is made so that the current passes through this heating 
coil as soon as it is turned on. This supplies the cold carburetor with 
the equivalent of the exhaust gas heat, which is available shortly 
after the engine has been started. 

Adjuatmenis. As will be seen from the illustration, the low-speed 
nozzle and air opening are fixed, the only possible adjustment, setting, 
or change being in the alteration of the nozzle or in the quantity of 
primary air admitted. The high-speed nozzle is fixed similarly so 
that it cannot be adjusted, the high-speed air valve G furnish- 
ing the only adjustment. The adjustment of this is very «\m\iV&'i 


with the engine running, advance the spark pretty well to the limit, 
open the throttle lever to its maximum, and then vary the position 
of the nut JV which governs the tension of the spring to the point 
where the maximum speed of rotation is obtained. This setting should 
be checked against actual high-speed running on the road, as there is 
usually a difTerence between the best road high-speed setting and the 
best engine-speed setting, with the car standing on the garage floor. 

Engine Should Start on the First Turn. In starting a car or any 
engine, whether located in a car or not, everj'thing should be inspected 
so as to know if all is right before attempting a start. With the 
novice, this is somewhat of a task, but to the old hand it is so much 
of a routine task that he does it unconsciously. If all conditions are 
right, the carburetor is primed and the engine will start on the first 
turn of the crank. If it does not do so, there is a source of trouble 
which must be remedied first, and it is useless to continue cranking. 
The trouble may lie iii^the fuel system itself, but exterior to the 
vaporizer, or it may be in the ignition apparatus. It is well in a case 
of this wort tu start with the gasoline tank and follow the fuel through 



remedy this, the method of procedure is as follows: Shut off the cock 
below the tank so that none of the previous liquid can escape, then 
drain off the carburetor and pipe into a handy pail. Next, open the 
union below the cock in the feed line and the one at the other end of 
the same pipe. At both places look for o.bstruction. Then clean the 
pipe out thoroughly, using flowing water, a piece of wire, or other 
means which are available at the time. 

Gasoline Strainer a Source of Trouble. If you find nothing here, 
look in the strainer of the carburetor to make sure that the flow is not 
stopped there by the accumulation of dirt and grit, filtered out of the 
fuel. The strainer should be cleaned often, but, like many other dirty 
. jobs, it is postponed from time to time. 

Should this source of trouble prove "not guilty" the carburetor 
itself becomes an object of suspicion. Is the fioat jammed down 
upon its seat, or are there obstructions which prevent the flow of fluid? 
Is the float punctured, or has one of the soldered joints, if a metal one, 
opened, or is it fiiel-soaked, if cork? 

Bent Needle Valve-Stem. To attend_ to this sort of trouble, 
disconnect the priming arrangement, take the cover off the' float 
chamber (it usually is screwed on with a 
right-hand thread) and take the float out. 
An examination of the float, Fig. 1.3^, 
will disclose whether it is at fault in any 
of the above-mentioned ways, all of whicli 
are comparatively easy to fix. If the float 
was jammed down, perhaps by priming, 
the act of taking it out will loosen it, 
provided that the stem of the float is not 
bent, and the needle valve or its seat is 
not injured. If the seat is scored, it should 
be ground-in just like any other valve, 
usmg oil and tine emery. A fuel-soaked 

cork should be thrown away if another is at hand to replace it, but if 
not, the cork float should be mo\'ed in its position on- the stem so that 
it sets higher in the liquid. In other words, move the cork up suffi- 
ciently to compensate for its loss of buoyancy. 

In case of a punctured metal float or of loose solder, the only 
real remedy in either case is to resolder. It usually happens VXv&V ». 


soldering outSt is not available out on the road, and some foim of 
makeshift will be necessary in order to reach a place where one may 
be had. "If the puncture is oo the bottom, it is sometimes possible 
to accomplish this by inverting the float so that the hole comes at the 
top where the gasojine seldom reaches it. If the flow be reduced to 
make sure that the float will not fiU up, it is possible to reach a place 
where a soldering iron may be procured. 

A remedy which might be tried in an extreme case of this sort is 
to fill the float to make it heavy, so that it will have a tendency to 
sink. Then take a spring of small diameter, cut off a short piece and 
place it in the float chamber so that it opposes the sinking action 
of the now heavy float. By carefully determining the length and 
the strength of this spring, the same action is obtained aa if the float 
were working all right. If the entrance of the liquid fuel is such that 
the sinking of the heavy float tends to close rather tbao open the gaso- 
line inlet, the spring would have to be on the bottom and fairly strong 
so as to oppose the action of gravity. But if the float works down- 
ward to open the gasoline passage, the spring will be at the botttun 
and very weak being there simply to prevent an excessive flow. 

Throttle Loose on Shaft. Now the carburetor trouble has been 


where, take tfaia off in neart^U of tni^pl»<iil wm^.i<' or niiitiUir ■■. 
>t8nces. The size of the pipe i<t nw-h that trn;, tliioj; in it Uir^i^ citoi 
to cause trouble may \)e iri>.tat)tly yft-n uinl niinr/ti\. 'i'}^. i, 
exception to tbU a a Amkll hok in tli': ifiW-pij^i; fa>ii;j/. r-hif d 
c-l':-£z*ti ev«i »hh a ;train of -lan*! or oi.h<-f ff>;)i/'n;(L v.j;) /,/,• o 
«-.:;*■ tru-/j*r -xTiii ti.^ mixture at all tUi,'-., l,j'. mJI Jiiv, 1^ , 
LaH :-;■ £i/i- ^tk-'ilirlv if it LajjI^-m t/, F>- ./ if , ..»,*„ »;.</w 
Tl't vt:-.*. « cry.K, '?^.':.*',;;.-r.^ *.}.f. fl//* «,' i,-, ,^: !•■/'.■. »•* »- 

-;^T«^- I* "_■' t". .■-*.-: i;.-; .V. ^■". '^ • y' v, ''i' ■.-. /^rj-f ?v 


motor will give better power and run faster with the throttle partly 
closed than when wide open. This happens when the auxiliary air 
valve does not open sufficiently to admit the large quantity of air 
needed at the widest throttle opening. The mixture, therefore, 
becomes too rich, and the motor starves. The auxiliary air valve 
usually has an outside spring, the tension of which is controlled by a 
milled nut, also on the outside. Then, when it is desired to make a 
change in the mixture, the nut is turned, altering the tension of the 
spring and thus altering the lift of the air valve; in this way the 
proper amount of air is admitted. To admit more air, the nut is 
backetl off in onlcr to weaken the tension and thus allow the air valve 
to o[>en wider. To admit less air, the spring tension must be increased 
so that the air vahe cannot open quite so far or stay open so long. 
Ailjii-ifmriil.t for Heating Water and Air Supply. On a large 
number of carburetors there are two more adjustments: those for 
heating the water and those for heating the air. The general run of 
carburetors are now water- jacketed to help \aporize the heavy fuels; 
during warm weather this may supply too much heat. For this 
mison, a cock is generally fitted to the hot-water line, which will allow 
partial as well as total closure. 

ilarlv, lii)t iiir is supplie<l to almost all carburetors to vapor- 



If you are ever bothered in this way, you may be sure, granting 
that the spark b good, that the trouble lies in the fuel system. From 
the description of the trouble, it appears as if conditions were such 
as to starve the. engine, although this was doubtless done uncon- 
sciously. This action is due to the fact that the gasoline level has been 
lowered so far that the suction of the engine does not draw up sufficient 
fuel for running. The fact that you have to prime to start and then 
prime to keep going, even this priming failing to work sometimes, 
would seem to prove that the engine is not getting enough fuel. The 
trouble is that the spray nozzle has been raised too high, so that the 
gasoline level is fom- or five times as far below the nozzle as it should 
be. The engine suction must raise the gasoline this distance before 

., KinB V»ri»tion o( Noiils Level. Fitit Picure, Correct: 

UccDDd. Too Low— Eniine Will Flood: Third, Too High— Eo^oe Will Stuvo 

any of the fuel will get into the cylinder, and if the distance exceeds the 
height to which the suction can raise the fuel, none will pass over. In 
a case of this sort, priming only helps temporarily. 

Wrong Adjastment of Jet Nozde. The wrong location of the jet 
nozzle results when the fuel level, as fixed by the float, \s not high 
enough to give the proper flow of fluel into the vaporizing chamber. 
Drivers who have trouble with this are frequently puzzled by it, 
because they assume that the carburetor is properly adjusted before 
• leaving the factory. This is not always the case. One young driver 

What is the cause of this very piuzling knock? My fouT-cylinder engine 
develops a bad knock on & hill, which can only be elinUDatri by retarding the 
■park, but when that is done, the engine "dies", that is, gives no power. The 
^ect is the same on level roads when the throttle is opened more than one 
third. I may have deranged the level o( the gasoline within the carburetor 
Would that have this result? 



Now, tliia trouble is directly traceable to the change in the level 
of the nozzle made when cleaning and is made unconsciously. To 
quote from a plain statement of the effect of this change: 

B) raising the spray nozzle, you lower the level of the gaaolioG relatively. 
Therefore, the liquid ia less sensitive to the suction, which would reduce the 
iLmount of gasahne used. At low speeds, there would be a tendency to atan't 
(hf eiiffiTie, which uvuld he mont noticeable on hilln. 

The trouble is that the spray nozzle has been raised so that 
the tiiKine does not get enough fuel at slow speeds and on hills. 
By lowering this a small amount. Fig. I."i4, the engine will be able to 
suck up more fuel ami the trouble ceases with the change. In making 
this change, be careful not 
to lower the nozzle too 
much at once, as the effect 
then is just as bad, the 
carburetor flooding at the 
slightest provocation. The 
better way is to lower 
the nozzle a very slight 
amount, say one-quarter 
of a millimeter, or perhaps 



care being in starting it. As the amount, or length, of the needle point 
within the tapered seat is small, the float need be raised but a small 
amount to clear that. Then, it may be lifted out as one desires, since 
it usually is made from a half inch to an inch smaller in diameter 
than the chamber within which it works. 

Smallest Detail Important. The influence of the smallest things 
may be of great importance, as illustrated in Fig. 136, A man having 
a small runabout with a rather large air vent in the gasoline tank, 
which was located directly over the engine, was bothered, in climbing 
bills, by too rich mixtures. These not only caused the engine to 
smoke badly, but caused a lack of power. On investigation, he found 

that the carburetor was 

located below and nearly 
underneath the gasoline 
tank. On a hill, the 
gasoline flowed out of 
the air vent, down the 
side of the tank, and 
dropped into the air in- 
take, thus increasing the 
mixture. Obviously the 
cure for this was to 
change the air intake so 
that the overflow from 
the tank could not drop , 
into it or into any part 
of the carburetor. The 
sketch, Fig, 136, shows howhewas advised to change it; the comment 
on the trouble and the proposed change were as follows: 

The addition of fuel, as you describe, to the air at the air inlet 
will seriously disturb the running of the engine and probably give 
so rich a mixture as to choke the engine. It is advisable to remedy 
this at once, and the best way to do so is to prolong the present air 
inlet upward and outward away from the gasoline tank which causes 
the trouble. To do this, have a sort of stove pipe made of galvanized 
iron, tin, or any similar metal.* It should be long enough so that its 
top is as high as the top of the offending tank, then make a big, easy 
bend away from the latter. The opening,or mouth.of the pipe should 

Fi«. 13S. Puiiling Ci>rbur«tor Problem Sotved 


he 30 formed as to take a screen, which is necessary to keep out the 
dust and should preferably he made removable, so that when the 
screen clogs with dust it 
can be taken otf, cleaned, 
and replaced. For this 
purpose use a very fine 
brass gauze, which can be 
obtained at anyhardware 
store at small cost. 

Pre-Heating the Air. 
One thing that gives a lat 
of trouble is the heavier 
fuel now supplie<i . It 
can he used successfully only by adding heat, the application of 
which may take one of two forma: a water or exhaust-gas jacket 
around the carburetor, or an arrangement pre-heating the air supply, 
The furnicr liiiiiiii! be jiddcd, but the latter can very easily. This is 
done, as shown in Fig. 1.S7. by 
running to the air Inlet for the 


the carburetor. In Fig. 13S is an English example of this, showing 
the carburetor connections on the four-cylinder Belsize. The pipe 
at the left is the inlet manifold and the one at the right, the hot-air 
pipe from exhaust manifold down to air inlet. In all cases this 
hot-air connection is made as short as possible. 

Causes of Misfiring. There are a number of vexatious things to 
make the novice and prospective driver peevish. Chief among these 
is the trouble known as misfiring. This may be described as a failure 
of the mixture to fire in any one cylinder. It is usually due to igni- 
tion, so that the term, as used now.means a failure to fire a charge due 
to an electrical cause. However, there are manj' common misfires 
which are due equally as much to a failure in the fuel-supply system, 
so that the latter meaning attached to the word is a misnomer. 

Among the causes which contribute to misfiring may be men- 
tioned ignition troubles, such as short-circuit in wires, exhausted 
battery, pitted or improperly adjusted vibrators of the coil, sooty 
or cracked plugs, loose connections or switch, dirty timer or com- 
mutator, punctured condenser, moisture in cpil, wet wires or cables, 
water on distributing plate, dirt or wear on contacts in distributor, 
or dirt or wear in timer. 

Then, there are the misfires due in part or wholly to the fuel or 
carburetion sjstem. These may be grouped or listed as follows : 

CarburetUm. and Fuel. Faulty mixture, sediment, or water in 
the carburetor, clogged gasoline strainer, leaky float, clogged spraying 
nozzle, bent float-valve spindle, stale gasoline, partial stoppage of 
fuel-supply pipe, hole or obstruction in intake pipe or manifold — 
these are not all the things that might happen, but are the principal 
ones which the miter's experience has suggested as most likely to 
occur to cars in general. 

Foremost among the several difficulties which may be called ' 
common misfires is the lack of a proper mixture. A rich mixture 
containing a relatively large proportion of gasoline in proportion to 
air is never desirable, inasmuch as it deposits considerable soot upon 
the piston, cylinder walls, and valves, and is, moreover, a waste of 
fuel. The motor will seldom run well on a very rich mixture, and 
the carburetor should be so adjusted that no more gasoline is fed to 
the mixing chamber than is sufficient for the motor to develop its 
full power. The exact mixture may be found by experiment. 


A very rich mixture will cause misfiring; the motor will have a 
tendency to choke at other than high speeds and is hkely to overheat. 
A lean or too thin mixture will, on the other hand, lower tiie efficiency 
of the motor, giving it a marked tendency to miss at high speeds, 
and is also accompanied by a popping soimd in the carburetor. In 
this case, the needle valve should be adjusted to admit more gasoline, 
or. if due to an excessive supply of air, the auxiliary air valve should be 
adjusted to admit less air. 

Bent Float Spindle. A bent float spindle will cause missing in 
one or more cylinders. The float spindle may become bent or it 
may become jammed into its seat by too vigorous priming. This 
may be discovered by unscrewing the cover and lifting out the float. 
Considerable care should be taken in straightening out a bent spindle, 
and the metal should be placed upon a block of hard wood, another 
block interposed, and the spindle gently tapped with a hammer. 

Leaky Float. A leaking metal float or a fuel-logged cork will 
cause missing, owing to its uncertain and erratic action, A cork float 
should be thoroughly dried out and then given a couple of coat3 of 
shellac to prevent it from absorbing the gasoline. As a new float 
is not at all expensive, the driver will probably find it more convenient 


I Summary of Qasoline System Troubles 

buretors should be among the \:\-^t things to change in case of 
A black smoke from tlie exhnu^t will iinliratc too rich a 
Too thin a mixture may cause back-firing through the 

iding oi Carburetor. This may be due to the failure of the 
alve to seat pro5>erly, which may be corrected by grinding 
i; or to a punctured float which must be removed and the hole 
■ soldered. It may also be due to the spraying nozzle being 
led that the opening is below the gasoline level. To remedy, 
: Dozzle by easy steps until the correct level is obtained. 
log of Gasoline Tank. This should never be done by lamp 
*n light. 

ks in Qasoline Line. These must be repaired as soon as 
ed. They may result in fire, destroying the ear and endanger- 
ives of its occupants. 

w Cap. The filler cap should uncover an opening in which 
ner of gauze wire which should not be taken out, or, if broken, 
1 be replaced promptly. As an additional protection against 
►reign particles getting into the gasoline system a funnel 
chamois skin through which the gasoline may be poured 
>e used. 

ide of Gasoline. For ordinary use, gasoline from 56 to 68 
test is most satisfactory. The former, called also stove 
, is the only kind obtainable now. 

(trucUon In Needle Valve Jn Carburetor. In searching for 
d gasoline line, it is well to unscrew the needle of the needle 
id then blow through the vatve. This will remove particles 
hat may be there. 


iflges in Manifold with Engine Developments. Notwith- 
; the marked attention paid to minor details of design in the 
« or four years, manufacturers have had no greater problem 
at of vaporizing the fuel properly, quickly, and efficiently; 
led to considerable attention being given to inlet-manifold 
Id the beginning, the inlet was a plain straight '^vecfc o\ 




tubing from what corresponded to the carburetor to the hole in the 
cylinder leading to the combustion chamber via the inlet valve. 
With the development of the four-cylinder motor, the majority of 
these were cast in pairs, and the pipe assumed a plain or modified 
Y-shape. Even at that, there was considerable chance for variety, 
as will be noted in the nine dif- 
ferent forms shown in Fig, 139. 
Changes from Fours to 
Sixei. With the coming into 
popularity of the six-cylinder 
form of motor, the inlet mani- 
fold received renewed atten- 
tion ; for now there were more 
variables, and it was a question 
of the best combination of 
them. One solution of this, as 
seen on a medium sized block 
six, is illustrated in Fig. 140. 
Here, the distance which the 
fuel must travel to the two 
central cylinders (cylinders S 
and 4) is so much less than the 
distance which the gases must 
travel to either 1 and ^ at the 
front or S and 6 at the rear , 
that there was the possibility 
of these four cylinders being 
somewhat starved. To com- 

, pensate. for this, the central 
part of the manifold where the 
three [»pes to the cylinders join fu. ui vnnrtyof iniet Miinifoidi r»d on sii- 
that from the carburetor was co,rf«»./ .v. ir lUiui PMUkin, co^rant. 
made much larger, with the 
idea of providing a well, or reservoir, for gaseous mixture large 

■ enough so the two central cylinders could not use all its contents. 
The majority of designers, however, preferred to make the dis- 
tance for the gases the same in each case, which led to some of the 
shapes seen in Fig. 141. Here it will be noted that a centce.V \qo^ S.?. 


used to make these distances come out etiiial in all but one case; in 
that, the cylinders are cast in threes with a single inlet for each group. 
Changes for Eights and Twehes. The coming of the V-tj'pe 
motors, both eights and twelves, has had another influence; for thej' 
came at the time when fuel was getting heavier and heaner. 
Designers were beginning to recognize the difiiculty of vaporizing all 
the heavy fuel before it reached the cylinders, and, to assist in this, 
they began utiliziiig the manifold. Consequently, the majority, 
if not all, the eight- and twelve-cylinder engines have manifolds of tlie 


Heating the Charge. The method of heating the charge has 
taken a number of forms. In a simple four-cylinder motor of the 

[mprovM Vsporiutial 

L-faead type, like the Ford, it has been possible to develop a combina- 
tion inlet and exhaust manifold (a single casting which would replace 
both of the former manifolds) which would give the heating effect 
desired in the inlet portion. Fig. 143 shows one way in which this 
is done and shows the central plate,or rib, between the two manifolds, 
which is heated to a high temperature by the exhaust gases, and thus 

has a large influence on the final vaporization of the inflowing gases 
OQ the other sade of it. It is clwned for this form that it will 9a.N«. 


from 25 to 40 per cent of the fuel used, and, even though {Ids duin ii 
not borne out in all cases, the fact that th«e is a saving shows tiiat 
this is a correct method. Many of the more modem motors are not 
only incorporating this as a method of saving fuel and increa^ng the 
motor's efficiency, but also of reducing the number of parts in the 
machine, the opportunities for trouble, and pos^bly of reduong 
weight. A secondary thought is the reduction in manufacturing cost 

Another way in which the ordinary fout^ and aix-cylinder inlet 
manifold has been altered is by the addition of the water jack^ 
previously mentioned for the V-types. A typical example of this is 
seen in Fig. 144, which shows a water-j^keted inlet manifold on a 
six-cylinder motor, although the water-pipe connections are not visible. 

Qianges in Construction of Manifold. In addition to the de«gn, 
the construction of inlet manifolds has been of marked influenoe. 
Thus a manifold of aluminum, iron, or other cast metal is usually quite 
different from what a manifold for the same engine would be if made 
from copper or steel tubing. In addition to the limitations of the 
process of production, there would be the changes which the surface 
produced would have. Thus, a casting would have a more or less * 
rough surface, while a drawn tube would be perfectly smooth. TTiis 
lallerdiuiiieteranii mure abrum 


idea of a leak can be dismissed, but, otherwise, a porous pipe can be 
discovered at idling speeds by squirting gasoline, upon the suspected 
surface of the manifold and noting if the motor speeds up. If it does, 
this is a sign that some of the gasoline has been drawfi through the 
holes in the manifold, enriching the mixture. 

The leaks around joints, connections, or gaskets can be found in 
much the same way. When the leak is found, the Joint should be 
tightened if possible, or a new gasket should be put in, or both. In 
the case of the porous manifold casting, it can be painted with a fairly 
heavy paint while hot so that the pores of the metal are well opened. 
Then, after this has dried in thoroughly, another coat will probably 
finish the job. If this does not prove to be the case, special cement 
for filling porous castings cau be purchased and applied; or, best 
at all, if the case is a bad one, an entirely new manifold should 
be put in. 


For storage of the fiiel required for the propulsion of a car and for 
feeding the fuel to the carburetor, many different systems are in use. 

Tank Placing. In automobiles, the gasoline tanks are generally 
placed under the front or rear seats, or under the frame at the rear. 
In many types of runabouts and roadsters, the tank is placed above 
the frame at the rear. 

Fuel Feeding. When .the tank is at the rear, or when it is under 
the front or rear seat, no special provision is necessary, under ordinary 
circumstances, to insure a positive flow of the liquid fuel to the 

Gravity. With the tanks placed high, the gasoline can be 
depended upon to run down to the float chamber by gravity. In 
mountainous districts it is sometimes found, in climbing very steep 
hills, that the angle becomes such tha^ the fuel will not flow, especially 
when the tanks are under or back of the rear seat, or when they are 
nearly empty. 

A means of getting around this difficulty is to place an auxiliary 
tank of one or two gallons capacity on the front of the dashboard, 
behind the engine and under the bonnet, and run a pipe direct from it 
to the carburetor. When the car is in a level position, this auxiliary 
tank fills automatically from the main tank, but a simple vaVve v^e- 



by more positive r 

vents the contents of the auxiliary tank from running back when the 
machine is tilted up. In thia way a sufficient supply for 15 or 20 
miles running is placed in a j>osition to reach the carburetor under 
any possible road condition. 

Air Prei^mtTe. With the tanks placed low, whether under the 
frame or above it, it Is necessarj' to feed the fuel to the carburetor 
,ns than gravity. One of the commonest sys- 
tems involves pumping a low air pressure into 
the tank above the fuel, so that this pressure 
forces the liquid out regardless of the relative 
heights of tank and carburetor. Ordinarily, 
a small hand pump is sufficient to provide 
such air pressure, though in modem auto- 
mobiles equipped with cnmpreised-air starting 
devices, or compressed-air tanks for filling the 
tires, provisions can be rea<lilj' made for sup- 
j)lying the tanks with air from these sources 
for the purpose of feeding the fuel. 

Exhaust Prcsnure. A system that is 
much used for providing pressure in the fuel 



the production of a new device, which is called the Stewart vacuum 
feed. Thb is a small compact circular unit, which is pUced on the 
dash under the hood for use with a rear tank and, when so used, 
eliminates the pressure feed. A sectional drawing of this is shown in 
Fig. 145. It may be described as follows: There are three connec- 
tions at the top, one to the gasoline 
tank, one to the intake manifold, 
and one to the air vent. Through 
the medium of the intake-manifold 
connection, the motor suction is 
communicated to the tank, for 
that is what the device amounts 
to. This produces a vacuum and 
opens the valve connecting with 
the gasoline tank That, as ueil 
as the connecting-pipe line, being 
air tight, gasoline is drawn in to 
fill the vacuum, floning mto the 
upper chamber with which the 
gasoline tank communicatee) 

This has a valve connection 
to the lower chamber, operated by 
means of a float; it in turn is con- 
trolled by the intake manifold suc- 
tion, through the medium of the 
system of levers. Bv it, the low er 
chamber Is kept filled to a fairly 
high level, whence feed to the 
carburetor is by gravitj This 
method thus does away with all 
the troubles of the pressure sj li- 
tem, at the same time allowmg of ^ "' 
the accessible and advantageous '^"""""'s(^'„„.„, .„„.„ 
rear tank location. It is placed as 

high as possible on the inside of the dash under the hood, hence there 
is never any trouble with the 'gravity feed even on the steepest hill. 
In one test, this vacuum-feed device increased the mileage of the car 
per gallon of fuel by more than 22 per cent. 



Prfssiire-Operated Feed Deriee. Carter System. Since the 
THtrotluction of the Stewart device described above, a number of 
(ievices acting on somewliat different principles have been brought 
out. In the Carter automatic gravity tank, as it is called, the suction 
and compression strokes of the motor are used to furni-sh the pressure 
which operates a .simple diaphragm pump, first in one direction, then 
in the other, Thi.s diaphragm pump is shown at the right of Fig. 146 
and is marked .1. As shown, this connects through a ball cheek 
valve B with the main gasoline tank, the strokes of the diaphragm 
pump drawing fuel mto the central well C, which, when filled, over- 



It is advised that this tank be connected to the engine in any con- 
venient place, except that near the exhaust manifold. When the tank 
has been connected and is ready for use, prime it with about half a 
pint of gasoline poured in through the filler cup on the top. After 
this has been done, the tank will continue to operate as long as 
there is fuel in the rear tank. 

Church System. In the 
Church system, the compres- 
sion, or explosion pressure, is 
used to lift the fuel through the 
medium of the specially designed 
check valve. A general layout 
is shown in Fig. 147, in which it 
will be noted that the check 
valve is mounted in the rear 
cylinder in place of the pet cock. 
Through this, the pressure is 
maintained in the main tank at 
the rear of the chassis, thus 
forcing gasoline to the auxiliary 
tank. Normally, the check 
valve will produce about one 
and one-half pounds pressure on 
the main tank, but the arrange- 
ment of the system is such that 
this maximum pressure is auto- 
matically increased to meet the 
conditions existing at any time. 
In this sketch, it will be noted 
that the pressure line is con- 
structed with a T, one part of *"™ "' ^^'^ ^"^ 
the pressure going to the auxiliary tank where it is regulated by 
means of a fioat, and the other going to the main fuel tank. 

By referring to Fig. 148, which shows a section through the 
auxiliary tank, the regulation of the pressure will be made clear. 
When the supply in the auxiliary tank gets low, the float /* drops down ; 
this moves the rod S down also. The downward movement of the 
rod forces down the valve R, which prevents the air escaping through 


the condensing tube, and thus the entire pressure in the sj'stem is 
exerted upon the main tank with the result that the pressure rises 
there. WTien more fuel is forced to the auxiliary tank, the float rises 
and allows the air relief valve R to rise; this opens the passage to the 
condensing tube again, so that tlie air can escape in that way and 
relieve the pressure upon the main tank. In this way, a balancing 
effect is produced, which automatically keeps the auxiliary tank well 

From this tank the fuel flows by gravity to the carburetor. 
There is, however, an additional and valuable feature of this system. 
On top of the tank will be found a vapor outlet 0, and in the sketch 
it will be noted that this is connected back to the carburetor. In this 
way any vap(}rizatioii which occurs jn the auxiliary tank is utilized. 
This has the double advantage of being a source of economy and of 
keeping the system closed against the entrance of dust. Provision ia 
made, despite this, for cleansing out sediment, by a drain plug at the 
bottom of the tank. The gasoline check valve will be noted at the 
top, this operates in conjunction with the float stem and air-relief 
valve, that is, the rising of the float in a full tank will automatically 
cut ofT further supply by means of the check valve, as well as by open- 
ing the air-relief valve at the bottom. Similarly, the downward 


As a further safeguard against breakage, and to aUow alterations 
in the relative positions of different parts, due either to the straining 
of the machine while it is in use or to a change of adjustments when 
it is disassembled or reassembled, loops or coils introduced at proper 
points in a pipe line are of great advantage. 

Stop cocks close to the tanks are an excellent safeguard against 
fire, since they permit the shutting off of the fuel supply in the case of 
any breaks in the line. Such safeguards should always be provided. 

With reference to the pressure system of fuel feed, there is hardly 
any limit to the precautions which must be taken to avoid leaks. The 
smallest leak puts the system out of commission as soon as the pressure' 
leaks down to a point where the fuel will not rise to the carburetor. 
When this occurs, the engine cannot be operated until the leak is 
found and fixed. To avoid leaks, many drivers go over all joints 
frequently and likewise replace all old packing. In addition, they 
wipe the joints with soap to prevent leakage and then cover them on 
the outside with tire tape or similar flexible material which can be 
wound on in such a way as to stay permanently. The rapid adoption 
of the Stewart device, since it was brought out in 1914, shows better 
than anj'thing else how troublesome was the pressure-feed system. 
Statistics for 1914 cars showed that in 237 different models, 109 had 
the gravity tank under the seat, and 31 in the cowl, this making 140 
with gravity feed, leaving 97 with the rear-pressure tank location. 
Similar statistics for 1915 show 52 per cent in favor of the rear tank 
location, while 1916 shows almost 66 per cent with rear location, and 
:34 per cent vacuum fed. 

Res«Te Tanks. To guard against the annoying mishap of 
having the gasoline give out while an automobile is in use, perhaps 
remote from any source of supply, many cars are now provided with 
reserve tanks which bold back one or two gallons of gasoline. This 
reserve cannot be used except when it is fed into the system through 
the deliberate intent of the operator. 

In its simplest and one of its best forms, a reserve tank takes 
the shape of a partitioned-off portion of the main tank, into which 
the gasoline automatically flows through an opening at the top when 
the tank is filled. It cannot pass to the carburetor until a special 
valve in the bottom is opened and the fuel allowed to flow back into 
the mun tank. 


A later and even moru simple provision is the use for the gasoline 
tank of A three-way outlet cock which has a fairly long extension up 
into the tank. The extension tube is open at the top and has a hole 
near tiie bottom of the tank which communicates through a branch 
tube with the third way of tlie cock. When the outlet cock is set for 
iiiirmal flow, the fuel feeds until the level reaches the top of the exten- 
sion; at that point it stops flowing. This is the warning to the driver 
tlmt his fuel is low. Then all he has to do is to turn the outlet cock 
to tlie other pojition, thus allowing the fuel to feed from the bottom 
liole of the extension tube. The remainder of the fuel, that is, the 
amount represented bj' the difference in level between the top and 
bottom of the extension tube, will carry the car to the next fuel station. 

Fuel Gages. The development of depth and quantity indicators 
has received much attention in the last few years, with the result that 
practically all new cars have some form of gage on, or In, the fuel 
system. On rear-pressure tanks, it is usually located on the tank, so 
the driver must go to the rear of the car to see how much fuel he has 
left, but on cowl tanks or those located under the seat, it is possible 
to ha\e the gage set on the instrument board or the dash, as tlie case 
may be, so that it is in plain sight. Practically all the gages give 
indications in gallons and fractions, so that with the gasoline gage and 


the fuel has gradually collected until there was enough to cut off 
the flow. A good way out of such a difficulty is to close connections 
at the tank and at the carburetor, take the entire fuel line off and 
blow it out with compressed air. This will clean it thoroughly. 

Lock on Fuel Line. The garage or repair man can insert a very 
efficient lock on any car by putting into the fuel line at a convenient 
point a shut-off cock which works with a removable key. These are 
readily obtained, and any good workman can install one in a couple 
of hours. Many owners of cars would be glad of an effident lock 
and would be willing to pay well for on&. This one has the advanta^ 
of being simple, cheap, and effective. 


Q. What is a carburetor? 

A. A carburetor is a device for vaporizing liquid fuels, and for 
adding to them, when vaporized, the proper amount of air for imme- 
diate and complete combustion. 

Q. How many types of carburetors are there? 

A. Three: the surface form, now out of date; the filtering type, 
no longer used, except on one or two English cars; and the spraying 
tvpe, to which all modern devices belong. The first was useful only 
with the very light and extremely volatile fuels of ten and twenty 
jears ago. 

Q. What are the essential units of a spraying type of carburetor? 

A. The essential parts of a spraying type of carburetor are: 
a float chamber with a float arranged to regulate the level of the 
inflowing fuel; a needle and nozzle, or spraying device, which should 
preferably be adjustable; an air opening, which may be variable or 
not, which may be in multiple form or not, which may have automatic 
valves to regulate its size or not; and a throttle valve to control the 
quantity of mixture passed into the cylinders. As an important 
auxiliary, the needle, nozzle, or- spraying device, whatever its form, 
should be placed in a special vaporizing chamber, of a size and shape 
to give the best results. 

Q. Do all these appear in all modem carburetors? 

A. Practically all, in one form or another, and also a consider- 
able number of additional parts. Thus many carburetors have two 
or more nozzles, or spraying devices;quite afew have two air ov^tv\u^. 


one of which is controlled by an automatic valve, some have three air 
openin{!s; many, in fact most, of the modern devices have a method 
of heating tiie vaporizing chamber, or the space immediately above or \ 
below it, so as to facilitate complete vaporization, as well as to quicken 
the action; some have air valves in the form of steel balls; others ' 
have pistons and dash pots to eliminate sudden movements or changes 
in operation; many have auxiliary devices intended to give a special 
starting mixture; practically all have removable strainers for cleaning 
the fuel, some having two different forms of strainer. 

Q. What is the generally accepted form of needle valve, or 
spraying nozzle? 

A. There is no one accepted form, although the majority of 
carburetors have spraying nozzles, or needle valves, which come into 
.one of four classifications. These are: the hollow nozzle with an 
opening at the top, slightly smaller in inside diameter than in outside, 
so that the spray of fuel is opened out in a fan-like form ; the same form 
with an internal needle having a long tapered point and screwing up 
into it from below, this giving a means of adjustment which the plain 
hole does not; the same plain tube and hole, with an external needle 
having a tapered point and screwing down into it from above (in 
this, the body of the Jieedle divides the spray of fuel); and the form 


Q. How does the auxiliary air valve remedy this? 

A. By adding air when the motor suction gets strong enough to 
open the auxiliary air valve, the amount added being in direct propor- 
tion to the strength of the suction. 

Q. What other disadvantage Is there in over rich mixtures for 
h^ speeds? 

A. An over rich mixture at high speeds shows a noticeable lack 
of economy, as at these speeds a great amount of gas is being used, 
and, if too rich, the gasoline fuel is being used up very rapidly. The 
makers of practically any carburetor equipped with an auxiliary air 
valve will guarantee a saving of 20 per cent in fuel consumption when 
it replaces a carburetor which has no auxiliary air valve. 

Q. Why are some carburetors water-jacketed? 

A. The conversion of a liquid like gasoline into a vapor is a 
chonical action which needs heat to complete it. If no heat is sup- 
plied, it will be taken from surrounding objects, or else the vaporiza- 
tion will not be completed. This abstraction of heat from the sur- 
roundings can be noticed in unjacketed carburetors in the form of frost 
or snow forming on the outside of the vaporizing chamber. The 
water-jacketed carburetor has the hot water of the engine system 
circulated through it to supply the needed heat, and thus assist and 
complete the vaporizing of the fuel. 

Q. Why are some carburetors supplied with hot air? 

A. This is done for the same reason. The pre-heated air is 
supplied to vaporize the fuel, instead of using cold air and supplying 
heat from other sources. In principle, it is practically the same as 
the other. 

Q. When hot air is supplied, how is this heated? 

A. Generally a stovJe, or a hollow member around the heated 
exhaust pipe, is connected by metal tubing to the air inlet of the car- 
buretor; in this way all of the air drawn in is forced to pass around the 
exhaust pipe, which beats it. This is not always the case, some 
makers using air sucked in from around the heated cylinders. Still 
others use an exhaust jacket on the carburetor, and draw the cold 
air supply in around this, so that it is heated. 

Q. What difference does the fuel make in this heating method? 

A. On the heavier fuels, such as kerosene, alcohol, distillate, and 
mixtures of these with gasoline, a great quantity of beat is necseasjU^ , 


as these heavier fuels are more difficult to vaporize and are also slower 
to start vaporizing. This means an extra supply of heat at starting 
time, and more than the usual supply at all times. It works out, in 
the direct use of e."diaust gases, through a. small pipe tapped Into the 
exhaust manifold, thus giving the highest available teoiperature. 
This is used through the carburetor jackets, but, in addition, the air 
supply to vaporize the fuel is heated. Another vaporizer of heavy 
fuels, which has been quite successful, places heavy metal weights 
inside the carburetor in the upper part of the vaporizing chamber and 
then forces the exhaust gases through hollow passages in these. In 
this way, the weights are heated up, and this heat is transmitted to 
the gas and air; the size and nature of the metal gives an equnble 
supply of heat, regardless of the exhaust gases. 

Q. What is the throttle valve? 

A. A valve placed in the pipe between carburetor and cylinders 
to vary (or throttle) the quantity of mixture flowing to the latter. This 
is generall\' connected to the throttle lever on the steering wheel, and 
to the accelerator pedal. General practice in driving, after the initial 
stages of learning, is to set the hand throttle at some medium point, 
and thereafter to var\- the speed of the motor bj' means of the foot. 
What is the general form of this throttle valve? 


Q. WhatUaVcDturitube? 

A. This is the essential principle of the inner member of the 
Venturi meter, invented for measuring the flow of water. It consists 
of two cone-shaped tubes diverging in opposite directions, with the 
proper relation of angles to one another and to the diameter of the 
smallest point, or meeting point, of the two tubes. The larger angle 
should be at the bottom, or entering end for the gases; the nozzle, 
or needle, should be just at or just below the smallest diameter; and 
the gases should flow through from end to end, that is, air in at one 
end, gas in at the middle, mixture out at the other end. In the true 
Venturi tube, the bottom angle is 30 degrees, the top angle 5 degrees. 

Q. When more than one nozzle is used, how are they connected? 

A. In practically all multiple-nozzle forms, the arrangement is 
such that the second (and later) nozzles are brought into action by 
increased demand from the engine, that is, automatically. In one 
case, a flap valve covers the second nozzle; but, as the suction increases 
this is drawn up and the nozzle is uncovered; having its own air 
supply, the nozzle begins to function as soon as it is uncovered, the 
amount of gas supplied by it depending upon the extent to which it is 
uncovered by the suction. In another, the first nozzle passes a fixed 
amount of fuel, as the engine demands rise; this suction is communi- 
cated to the second nozzle and the fuel standpipe from which it draws; 
it is put into action, but varies its supply always according to demand. 
The combination of fixed and variable nozzles gives reasonably 
good vaporization at all possible speeds and under all variations of 

Q. What Is a horizontal-outlet carburetor? 

A. The first carburetors were all connected to the engine cylin- 
ders through the intermediary of an inlet manifold. The latter con- 
nected up to the cylinder horizontal face at a number of points, and 
was carried down to a single flange for the carburetor connection. 
While the surface of this flange was horizontal, the outlet on the car- 
buretor, that is, the passage to this, was vertical. Consequently, 
carburetors made to fit this arrangement are said to have vertical 
outlets. With the principle of block casting, it is usual to incorporate 
the inlet manifold in the cylinder casting and have a single carburetor 
opening and place for attaching, this being a vertical face. As the 
face, or carburetor flange, is at right angles to the body o{ live cmW- 


retor outlets, this brought about a horizontal outlet. A carburetor 
with this form of outlet, and intended to bolt directly upon the cylin- 
der casting in the manner just described, is called a horizontal- 
outlet carburetor or a horizontal carburetor. 

Q. What is a double carburetor? 

A. A double carburetor is one made for a V-type of motor in 
which a common float chamber supplies fuel to two separate and 
distinct groups of vaporizing chamber, fuel nozzle and needle, air 
inlet, etc., each half supplying one of the blocks of cylinders. That 
is to saj-, it is a double carburetor, or two carburetors, if that Is easier 
to imdcrstaiu], each one of which supplies one-half of the engine's 
cylinders, but has jiothing to do with the other half. It has been 
foimd that better results can be obtained in this way than in any other. 

Q. What has been the effect of vacuum feeds? 

.\. The principal effect has been to raise the carburetor. For- 
merly, the ciirburetor had to be set low so the fuel could flow to it, and 
e\en when pressure became general, the carburetors were still set very- 
low. Now, with auxiliary tank feeding, it is possible to raise the 
carburetor from twti to six inches, and practically all designers have 
taken advantaf,'e of this. It makes the carburetor easier to adjust, 


el would flow to it on the steepest hill. The substitute for this was 
essure, but this necessitated much apparatus, and the system had to 
■■ kept air tight, or it was useless. In this form an air pump forced 
r through a regulator into the air-tight tank, this pressure forcing 
e fuel out and to the carburetor. The latest device is similar to the 
£uum tank but is operated by utilizing the pressure of tlie exhaust, 
>rking through a pressure-regulating valve. 

Q. Describe this exhaust-operated system? 

A. The exhaust gas pressure is cut down to a few pounds by the 
gulator, and goes thence into the rear gasoline tank. Here it 
sates pressure and forces out gasoline which must flow to the auxil- 
ry tank. As the tank fills, a float rises, and with it a needle, which 
)se3 a connection to the outside. When the tank is filled to the 
edetermined level, this arrangement opens the outside connection, 
jd the exhaust gas is free to escape. As the fuel flows to the carbu- 
tor, tiie float drops and, in time, closes this opening, when the 
haust pressure starts the fuel flowing again. So the arrangement 
float and outside opening keeps the auxiliary tank continually filled. 

Q. When no fuel flows, yet the tank is filled, what Is the 

A. If the tank is full and no fuel flows, there must be an obstruc- 
>n in the line somewhere. Try the gasoline pipe line first for a bend 
kink. If none is found, try the carburetor connection. Failing 
at, remove the strainer and in.spect it. Then look into the float and 
■at chamber, float valve and outlet to vaporizing chamber. Some 
le of these is sure to be at fault. 

Q. How can a punctured float be managed, so as to get home? 

A. Let the float sink, but oppose this sinking by means of a 
ring, cai»f uUy cut to the right length to give the same effect as if the 
lat were O. K. This will carry the carto the nearest repair shop, or 
eking that, will take it home. A punctured metal float can readily 
: soldered, but should be dried out very carefully first, this being done 
imanly to make sure there is no more gasoline inside, nor any vapor 

Study Questions for Home Work 

1. Describe the construction and operation of the Stromberg 
odel "H". 

2. Tell bow the main jet is replaced on the Zenith. 


3. Give tlie method of making a. slow-speed adjustment on the 
Ford I'Jir. 

4. How many adjustments has the Brovme carburetor? 
Describe them. 

5. Describe the construction of the Master carburetor throttle, 
(i. How doca the Lfinguemare differ from other carburetors? 

7. Mention in detail the process of starting adjustment of 
the Webber. 

8. How many adjustments has the Ra^-field? Describe them. 

9. Tell in detail the principle upon which the Bail and Ball 
carburetor works. 

10. What is the mixture-indicating pointer on the Newcomb? 
What are its advantages? 

11. How would you adjust a new Schebler Model "L"? 

12. What is the pre<]ominating feature of the Stewart car- 

13. How in the Johnson carburetor adjusted? 

14. What are the salient features of the Packard carburetor? 

15. Describe tlie adjustment of the Cadillac, (aj low speed, 
(b) starting, (c) high speed. 

16. Select and describe the working of a heavy fuel carburetor. 



Importance of Valves. Probably the most important thing 
about a four-cycle gasoline engine is the valve, or, more correctly, are 
the valves, for the usual number is two per cylinder. The opening 
and closing of these control the functions of the engine ; for if the valve 
does not open and allow a charge of gas to enter, how can the piston 
compress, and the ignition system fire, a charge? Similarly, if the 
exhaust valve is pot opened and the burned ^ases allowed to escape, 
they will mingle with and dilute the fresh, incoming charge, possibly to 
the extent of making the latter into a non-combustible gas. This 
is purposely stated in this way because both methods mentioned 
have been utilized for governing the engine speed, although not to 
any great extent in automobile work. 

Summary of Valve Features. In the valves and valve mech- 
anisms of modern gasoline engines there have been and are impending 
more interesting changes than seem in prospect in any other portion of 
the mechanism of the modern automobile. Particularly is this the 
case with reference to the present tendency to discard the poppet 
valve with its many objectionable features. Even where there is no 
tendency toward the use of a sleeve-valve or slide-valve form of 
motor, much experimenting has been done with increasing the number 
and changing the position of the valves. 

Poppet Valixa. Though the very first internal-combustion 
engines ever made were operated with slide valves, the poppet valve 
was introduced very early in the history of this art, and has reigned 
supreme in practically all types of gas and gasoline engines. 

The chief advantage of the poppet valve is its capacity for con- 
tinuous operation at excessively high temperatures, but since the 
cooling of engines baa progressed to the status of MgU Te\\«?Q%X.'^ , 


this advantage is of less importance than formerly. And the dis- 
advantages of poppet vah'es — the small openings that they afford, 
the noisy and hammering action they involve, their tendency to leak 
and in other ways give out, and the necessity for frequently regrinding 
them— are objections so serious that it is no wonder the prospect of 
their elimination is so widely welcomed. J 

About the only recent improvement that has been made in 1 
poppet valves is in the quality of material used in them. Many 1 
valves now used have cast-iron and nickel heads, which offer a max- 
imum resistance to warping from the heat to which they are subjected. 
These are fitted with carbon-ateel stems, which are superior in their 
wearing (|ualities. More use has been made recently of tungsten 
as a material for valves. Steel containing this is even harder than 
nickel steel, and experiments have shown that it does not warp as 
much. In practice, the objection found to cast-iron heads was thai 
the fastenings to the carbon-steel stem were not sufficiently strong 
to withstand the constant pulling and pushing to which a valve was 
subjected. As a result the;' separated, causing trouble. 

In the operation of poppet valves, the cams become an important 
factor. These are the parts which, in revolving, raise the valves so 


cylinder engines which have the cylinders cast in threes, instead of in 
a block, as the one referred to. On some motors where this construc- 
tion has not found favor, the designers have followed the plan of 
enclosing the individual valve mechanisms. While more expensive, 
this method is equally as efficient. On the other hand, it adds to the 
parts, and the whole modern tendency has been to reduce the number 
of parts. 

Sleeve Valves. This type of valve, while not at all new, has only 
within the past few years come into considerable prominence, chiefly 
as a result of the truly remarkable performances of the Knight motor, 
which is equipped with the most advanced examples of this type 
of valve. 

Contrary to past opinion, it has been conclusively demonstrated 
that sleeve valves do not, to any perceptible degree, increase the 
tendency of a motor to overheat, nor do they wear at any very meas- 
urable rate. They afford, moreover, in the best constructions, a much 
higher thermal and mechanical efficiency than it is possible to secure 
from the average poppet-valve motor, this improvement being due to 
the better-shaped combustion chamber that can be used and the 
greater areas of valve opening, which facilitate the ingress and egress 
of the charges. 

Another advantage in favor of the sleeve valve is that its timing 
is permanent and unchangeable and does not alter materially with 
wear. Not the least of the merits of the sleeve valve is found in 
the fact that it lends itself to positive operation by eccentric mech- 
anisms, which are in every way greatly superior to the non-positive 
cam mechanisms universally used to actuate poppet valves. 

A very good example of this latest type of Knight motor is 
illustrated in Fig. 149, showing the intake side of the Moline-Knight 
four-cylinde^ motor. 

Sliding Valves. Sliding valves of other than the sleeve type, 
embracing a considerable variety of piston valves and valves similar to 
those employed in steam engines, have not found as much favolr with 
designers of automobile engines as have other types herein referred to. 

One exception is the successful use of a "split-ring'' valve sliding 
up and down in the cylinder head just above the piston, which has 
found successful application in a few motors recently built by the 
Renault Company, of France. 


Rotating f 'aires. A number of engines witli n)tating valves lia^'e 
!>een built from time to time, but none of these seem to have survived 
the test of time, for not one which was in evidence two years ago ia 
being made now. A case in point is the Speedwell car with the Mead 
rotating- valve motor. Tlie motor was excellent but is no longer made. 

Half-Time Shafts. For the actuation of the valve meclianiam 
of any four-cycle motor, it is necessary to have a shaft (or in the case 



The most impurtant recent innovatinii in this detail of autn- 
inobtle mechanism is the driving of Iialf-tiine shafts by silent chains 
in place iif the lon]i;-nse<l gearing; of spur anrl Iielical type. By this 
improvement the noise of the fjears is eliminat<.'<l. 

A tj-pical silent-chain installation, driving half-times haft and 
other shafts as well, is .seen in Fig. ir>0, which presents the King eight- 

cylinder motor witJi the chain cover rcmiived. Tliese occupy the 
compartment formerly called the gear case, or gear cover, when all 
driving was done by gears. Here it «ill l>e noted that there are twr) 
sprfjckcta on the crankshaft; one driving the camshaft thn)Ugh the 
medium of a third sprocket whidi servos a doulile pur(Kisc, as a tWm 


tightener and as a drive for the pressure oil pump; while the other 
sprocket, through a second silent chain, drives the electric generator 
at the right, no tightener being needed as the generator can be 
moved sufficiently to care for this. 

In the Cadillac motor, shown in Fig. 2, Part I, a pair of gears is 
used, one driving the camsliaft from the crankshaft, while the other 
drives the auxiliary shaft from the camshaft. In the American form 
of Knight sliding sleeve-valve motors, shown in Fig, 149, a pair of 
silent chains is used for the eccentric shaft on one side and the electric 
generator on the other. These are driven from a pair of sprockets 
set side by side on an extension of the crankshaft. 

A point that should be brought out in connection with silent- 
chain camshaft driving is that the use of the chain allows the siiafts 
to be placed anywhere desired and thus, to a certain extent, frees ■ 
the designer from the former restriction of a two-to-one reduction I 
ratio in the gears, which rather fixwl the size and, consequently, thft'' 
position of the gears. This restriction had an influence also u])on 
cylinder design, as the center of the camshaft fixed the center of all the 
valves, that is, their distance from the center line of the motor. 



TItnInx Resulation of a Number of Prominent French Motors 


, 1908. 

^ h.p.. 4 cylmden. . . 
10/14 b.p., 4 cylinder, 

ColtiD-Dei»«outt«— 18/22 h,p, . . 
Broubot — 12 h.p., 4 try linden. 


PeufCDt (Bta^itti). . 
■— OVp. ■"""■ 

Parmt— 1* fa.p., 80/100 

Dimusj— 10/12 h.p., 100/120. 
Vinol-Degi^ilBnd — i'2/lOb.p.. 

SulWn— Q/12 b.p., 4 ej'lindua, 


HtMult— 8 b.p.. 2 cyliade™. . . . 
Umc— 20h.p,. 7S/110 

n ATrmiiced ia Cbe order of Ibeir in 

II ipeedi. Tba anclu 

be advuiced at nUicdad b] 

hJ by tba drir«r. 

In laying out or designing a set of cams for a gasoline engine, 
such as is used on an automobile, it is first necessary to decide upon 
the exact cycle upon which to operate the engine. By this is meant 
the exact length of time, as referred to the stroke, in which the valve 
action will take place. Upon this subject, designers all over the 
world differ, and no wonder, as this cycle can but be judged by 
results, for it is impossible to watch it as it transpires. Deductions 
differ, therefore, as to what happens and, consequently, as to the 
effect of various angles of banning and ending of the \a.We w^cjt^. 



TiminE ResuUtlon on a Number of Prominent American Motors 









46'' 48' 

11° SO- 


29^ as' 



Abball Bdk Ii[d 













31° 34' 


20° 00' 


rhsL.?or?* '''■ ""•"'' - 


35° 00- 

as- 00' 



c^-it'L,':.'. :::; 





Of ay 


35° OO' 



(■y!^l!lh-Vc . 

13° 00' 

■ *fl° OO' 

47° DO' 



60° oo; 

12° (W 

KrnQklin"\"l . . ". 



81° 30' 


as; 00- 

35° 00' 

li"yuv:,,%)!'-^\'Aud 2S 

47° 00' 


Ilu lit^-J 


28" IW 

40° 00'. 


Jui:k«m Olyiiipk. Kl;^e^li>-. and Sultuic 





16° oo; 

38° OO' 

15^ 0(1' 

King B. 

48° 00- 



30° 31,' 



KrilM, . 



39= 00- 





30° 00' 





10° 27' 

McFirlon 11-T . 

10" 00- 



Mu»i.|l 4-3S, . . 





a- 00' 

3Li° 00' 











Mujer E ami CI 


40° oo; 




45° 0.1- 




of comparison with the valve data of American tj-pes, TaWe II. The 
valve timing for American cars as produced in 1913 and 1914 is 
given in Table II, while Table I was compiled in 1908; a comparison 
which indicates in a measure the advance in the past five or six years. 
In studying these tables, it should be home in mind that all angles are 
spoken of in terms of the crankshaft and are usually referred to the 
two dead centers, commonly spoken of as the upper dead center aod 
the lower dead center. 

In Tables I and II, it will be noted that in so far as maximum 
openings were concerned there has been little change. The earliest 
exhaust opening of 1908 was Mutel at 02°; the earliest American 
exhaust opening of the present is Simplex 50 at 57° 30'. The former 
closed at 28°, while the latter closed at 15° 40', thus giving the French 
motor a total exhaust opening of 270°, while the American has but 
2.)3° 10'. Simplex is not a representati\e American car, howe\er; 
it is a special model with racing characteristics, and is built only to 
order. Crescent and Reo are the real leaders. 

With reference to inlet valves, the situation is somewhat similar, 
the largest foreign lag in opening is the Unic with 34°; while the 
largest American opening lag is the Hupmobile with 21°. In dosing, 
the highest figure reached by the foreign product is 58° bj' Peugeot, 
and on this side, 49° by Chevrolet. The former shows also the 
greatest total, 254° ; but the largest American total is that of Crescent 
with 245°. 

These, however, represent the extreme cases, and the averages 
tell a different story. The average foreign inlet opening (total) in 
1908 was 232°, while the average American inlet opening is now 
239.3°. Similarly, with the exhaust total opening, the average foreign 
figure then was 214.5°, the a^■e^age American figure is now 220.2°. 

It is unfortunate that the speed at full power output of the 
.\merican motors is not available also, as that would allow an even 
more interesting comparison of the two tables. In Table I, it will 
be noted that the motors are arranged in the order of their maximum 
speeds. Were the American speed figures available, it would show 
.for one thing whether speeds of today are, as claimed, so much 
higher than formerly and also, what is more to the point, what valve 
setting' gives the highest speed. Referring to Table I, it will be seen 
that Unic with the greatest lag of inlet opening and the %tfc*.\«?.\. 


total inlet opening is next to the highest in speed, whereas the others 
having high lag figures are all down among the moderate speeds. 

Now, if the average of the nuiueroua examples of good practice 
be takeii, it is not a hard matter to explain the form of the cam and 
its derivation. The height of the upper surface of the highest part 
of the cam above the surface upon which the valvt^actuating device 
normally rests determines the lift of the valve, which is the name 
given to the amount it is opened or hfted. This is not really the lift 
of the valve because of the fact that in all valve-operating systems 
there is a certain amount of clearance between the lower end of tlie 
valve stem and the upper end of the valve lifter mechanism. This 
clearance must be taken up by the cam before the valve itself is 
actually lifted, so, to obtain the true lift, the amount of the clearance 
is subtracted from the lift as determined by the cam height. Know- 
ing this, designers usually predetermine the clearance and allow 
for it in the height of the cams. 

Typical Valve Actions. Figs. 151 and 152 illustrate the complete 
valve action very well; the former, that of the Locomobile Company 
of America, Bridgeport, Connecticut, showing the form in which the 
cam works against a roller in the bottom of the push rod. Thi.s works 
upward in the push-rod guide and has a dirt excluding arrangement 



in this way the wear is Retributed over the whole flat face, which 
in this construction can be made much hirger than can the face of 
the roller. The push- rods are of the "mushroom" t>'pe and are 

Fie- 151. Complete Valrc 
MoSoD with Bflib Path Rod 
CmrUtg if LoeowuMt Campanr 

ri|. 152. Complete ViIte Motioa 

2. Complete 
hout RoOeTiD 

made of nickel steel. The push-rod adjustments are completely 
enclosed but may be readily reached without disturbing any other 
unit. They may be removed and replaced without removing the 
valve springs or valves. 


Neither of these systems is in decided favor, designers being 
about equally dividec! between them. 

The construction and operation of the cam mechanism is the 
same whether used in connection with an exhaust or an inlet valve; 
as the 3«me line of rea^ionitig and the same method of procedure, 
in both cases, would lead to the same results. 

It has many times been tried and still more often urged that 
the straight surface of the side of the cam is not conducive to the 
best results, because of the fact that when the first straight portion 
of the cam surface strikes the cam roller it does so with so much 
fnrce that it tends to wear the latter in that direction. As for the 
receding face, it has been urged that the ordinary closing of the 
valve is ttm slow and that the straight surface can be altered so as to 
allow of speeding up tlie downward movement of the valve. This idea 
works out into a curve; 
'' p^|f^|:';{;!;ijJ'!|S |^r;=|'!': ^|i g|t! the back of the surface is 

"— j- ■!■■■-! |---t----t^^^i:;^l-;-^p'.[i:lJ^ hollowed out so that as 
T ,' j soon as the cam roller 

I y' : I passes the center it drops 

H ': • ; [; ;;;[;;; ■ {j^ ; ;; j | ; ^ ;j " ; T ;;:[ ^ ^ H '^;;i j i !|^ vertically, owing to the 

T|:iu{!i^Jj^t^iljin.^ : ;: - jii: - | :i-i ^ T ^^ tension of the spring. 


of the piston, which results in a much larger piston charge. The same 
practice is carried out with the exhaust, hut as the presstue is higher, 
so large an angle is not necessary. These actions take place on 
the back — flat side — of the cam surface and have given to the high- 
speed automobile engine a larger charge and a more complete 
scavenging effect, resulting in more power and speed from the same 
size of cylinder. 

As proof of this statement, the power curve of an engine of 
but Si'inch diameter of cylinder is shown in Fig. 153. This size of 
six-cylinder engine would be rated by any formula at about 29 
horsepower at the maximum speed, and a commercially obtainable 
type in this size would doubtless be guaranteed to deliver between 
20 and 25 horsepower. This engine, which is not built for racing 
purposes, displays a power curve which continuously rises; a speed at 
which it would turn downward has not been obtainable in the tests. 
This curve shows also that the maximum power obtained was over 
8(), which is nearly three times the power of the ordinary engine of 
this same size. This result is ascrihable to superior valves and 
superior attention to the valve angles as governed by the cams. 

Number of Valves per Cylinder. Three Valves per Cylinder. 
When it was stated that but two valves per cylinder were ordi- 
■ narily used, with one cam for each, the majority case was spoken of. 
But, as it is a fact that there are other cases which differ from this, 
it would not be fair to close the subject without mentioning them. 
The most prominent advocate of air cooling in this country and-the 
world, the H. H. Franklin Manufacturing Company, used three 
valves, and consequently three cams, per cylinder. These three were 
the ordinary inlet; the usual exhaust; and the additional auxiUary 
exhaust. By re-designing later, this complication was avoided and 
the third valve eliminated. 

The Wisconsin Motor G>mpany has developed another motor 
with four valves per cylinder and, after a notable racing success, 
has placed it upon the market. Any maker desiring to do so, may 
pivchase this and incorporate it in his chassis. This emphasizes the 
distance which the sixteen-valve four-cylinder motor has progressed 
in the space of a year or so. A section through this motor, both side 
elevation and end view, showing all the details of the construction, 
is shown in Fig. 1 54. A full view of the intake side is given in F\%. \&^. 



Four Valves per ('ylinder. The very latest practice in the way of 
multiple valves is the use of four valves per cylinder — two inlets and 
two exhausts. There are a number of reasons why this construction 
is a good one. It is said that the area through which the gases enter 
and leave the cylinder can be made greater, thus giving the same or 
greater supply of gas more quickly and, after using it, ejecting it with 
the same or a greater volume more quickly. The volumetric efficiency 

Pia. t.S.'i. View of iDtakc Siilc of Sixtecn-Valvn Malur 
C'ourtdv o/ »'>>cnn.i>i JToTor CamiH-nt. Hilir'iukf. Ilirottin 

of the cylinder Is greatly intTeased in this way, giving more power and 
ajteed from the same size of cylinders, so much more, it is claimed, as to 
make a four-cjlinder engine with sixteen valves the equal of a six- 
cylinder with but twelve valves. Another big advantage claimed for 
the smaller lighter valves of this construction is that very much lighter 
valve springs can be used. This advantage was discovered by using 
sixteen valves on four-cylinder racing engines where the comotc^TOW" • 


and other pressures were enormous. The valve springs for the ordi- 
iiarj' eight-valve engine had to be very stiff and, consequently, gave 
much cam trouble. The stiff springs dug out the sides of the cams very 
rapidly and also failed rapidly themselves. With the lighter springs 
which can be used with sixteen valves, these troubles are eliminated. 
In the .'i9 cars starting in the last French Grand Prix, all but 
three were four-cylinder forms. Of these 36, two ha<! sleeve vah'es 
and three had the usual number of valves, but the other 31 all had 
sixteen overhead valves. These were about etjually divided in 
respect to camshafts, 17 ha\'ing but one, 14 having two. In the 
recently developed Stuiz motor, made by the Wisconsin Motor Com- 
pany, the engine has the outward appearance of any other T-head 
form, for the use of double the usual number of valves does not change 
the exterior at all. 

One Cam per Two Valves Influences the Shape. A case in which 
the cam does differ is that of the use of two overhead valves operated 
by a single camshaft, Fig. 156. This 
practice originated with the F. I.A.T. 
Company', which brought it out f(tr 
racing use only, where it was partii-u- 


the low side. In the form shown ip Fig. 137, the eight-cylinder motor 
used in the Briscoe 38, made by the Briscoe Motor Company, Jackson, 
Michigan, there are no unusual features. The single camshaft with 
16 cams b centrally placed in the middle of the V and operates tiie 
push rods, inclined outward, parallel to their respective groups of 
cylinders. A rocker arm, or follower, is used at the cylinder heads to 
transfer this up-and-down motion to the valves which are set in 
the center of the cylinder heads and are thus parallel to the push rods. 

Ff. 157. SKtioa through Briuoe Eight, Showinc < 

In the majority of V-t\-pe motors, both eights and twelves, the 
valves are in side pockets; the cylinders are of the L-type, and thus 
there is no radical innovation except the inclined push rods and vahe 
systems. In a few of these motors, however, a follower is used 
))etween the cams and the push rods because of other structural reasons. 

When any kind of a cam follower differing from the usual direct- 
lift push rod is used, thi; may or may not affect the shape of the cam. 
r.sually it does not, so that the shape does not have to be taken into 
account. Ordinarily these followers are used to prevent side thrust 
on the push-rod guide, the follower itself taking all the thrvist mA 


being sn designed as to be readily removable or adjustable, to take 
fare of this. In cases where this does not obtain, the object usuaJly 
^riupht is the rcnmviil of noise. The two objects may be combined, as 
in the case shown in Fig. 158. This 
represents an enlarged view of the 
cam mechanism of the famous one- 
cylinder French car, Peugeot. It 
will be clear that the action is that 
of one cam operating both tbe 
exhaust and the inlet calves through 
the medium of a pair of levers, upon 
which the cam works alternately. 
A cam follower of somewhat 
different form, but one achieving the 
Me i.'.s Cam Mrr-hBmsm of Peugeot Same results, Will be noted in the 
Cadillac eight-cylinder motor, shown 
ill Fig. 1H4. where attention has been called to these, and also in the 
Chalmerssix-fyliiidfT motor with overhead valves, shown in Fig. 156. 
Difficulties in Making Cams. There was a time when the pro- 
duction of a guild, accurate camshaft was a big job in any machine 



Qrinding Increases Accuracy. An even later improvement in 
the way of a machine for producing cams on an integral shaft is 
the grinding machine which has been developed for this purpose. 
This works to what is called a master camshaft, that is, a larger 
size of shaft which has been very accurately finished. This master 
shaft is placed in the grinding machine, the construction of which 
is such that the grinding wheel follows the contour of the very accu- 
rate master shaft and produces a duplicate of it, only reduced in size, 
a reducing motion being used between master shaft and grinder- 
wheel shaft. 

The result of this arrangement is a machine which is almost 
human in its action, for it moves outwanl for the high points on the 
cams and inward for the low 
spots on the shaft. Moreover, it 
has the further advantage that 
all shafts turned out are abso- 
lutely alike and thus accurately 
interchangeable. It allows also 
of another arrangement of the 
work, the drop forging of the 
shafts within a few thousandths 
of an inch in size; the surface of 
skin is easily ground off in one 
operation, then the hardening is 
done, and the final grinding to 
size is quickly accomplished. In this way, the shafts may be 
produced more cheaply than was formerly the case and have, in 
addition, the merits brought out above, namely, greater accuracy, 
superior interchangeabitity, and quicker production. 

The same process is applicable to, and is used for, other parts of 
the modern motor car; thus crankshafts are ground, pump and mag- 
neto shafts are finished by grinding, and many other applications of 
this process are utilized. The process can be extended indefinitely, 
the only drawback being that a master shaft is very expensive. 

Old Way Required More Accurate inspection. With the old 
method of making the cams and shaft separate, the amount of 
inspection work was very great and represented a large total expense 
in the cost of the car. Thus, it was necessary to prove up every cam 


separately, as well as every shaft, ami, later, the cams and shaft 
assembled. One t>f the forms of gages used for inspeeting ct 
(3 shown in Fig. Ifi-. It is in two pieees, dovetailed together. This 
allows of the testing of many shapes of eam with but one base piece k 
and a number of upper, or profile, pieces equal to the number of differ- ii 
cnt cams to be tested. To test, the cam is slipped into the openitig, L 
and if small, the set screw forces it up into the formed part of the i, 
gage, showing its deficiencies; while if large, it will not enter the form, 1 1] 

Valve Timins 
e of speed without material alteration in the engine 
V repair man aims to get when he goes over the timing of the 
motor. Valve timing has been 
called an art, but it is not; it is 
only the application of common 
sense and the known vah-e dia- 
gram to the motor in an attempt 
to get the best all-around results. 
These, as might he expected, are 
a compromise, and that repair 
man does the best timing, who 


until a mark or the desired mark is brought up to the pointer. Thus, 
the cylinders are marked from front to back always, that nearest the 
radiator being 1, the next 2, then 3, and the last, in the case of a 
four-cylinder motor, 4. In a six-cylinder motor the method is the 
same with the addition of two cylinders, the one nearest the dash 
being, of course, 6. The flj-wheel sometimes has the positions marked 
on its surface, as well as the valve operations. Referring to Fig. 162, 
this shows the valve-timing diagram of the four-cylinder Over- 
land for 1915. Xotice in this that none of the valve operations begin 
or end on a dead center point so that even if the centers are marked 
on the flj-wheel (as they are in this case) this is of little benefit except 
as will be pointed out. The marks on the flywheel are as follows, 
this showing also what they indicate. In referring to these it will be 
remembered that on a four-cylinder crankshaft the first and fourth 
crankpins are up (or down) together, while the second and third are 
down (or up) together: 

1-1 UP Means that pistons in cylinders 1 and 4 are in 
their uppermost position, or at upper dead center. 

2-3 UP Means that pistons in cylinders 2 and 3 are in 
their uppermost position, or at upper dead center, 

1-4 I-O Means that inlet valve of cylinder 1 or 4 (not both) 

1-4 I-C Means inlet valve of cylinder 1 or 4 closes. 

1-4 E-0 Means exhaust valve of cylinder 1 or 4 opens, 

1-4 E-C Means exhaust valve of cylinder 1 or 4 closes. 
' 2-3 1-0 Means inlet of cjlinder 2 or 3 opens. 

2-3 I^ Means inlet of cylinder 2 or 3 closes. 

2-3 E-0 Means exhaust of cylinder 2 or 3 opens. 

2-3 E-C Means exhaust of cylinder 2 or 3 closes. 

The firing order of the cylinders is 1-3-4- 2. To apply this 
knowledge, open the pet cocks so the motor will turn over easily; 
selecting cylinder 1 to start with, turn the flywheel Until the mark 
1-4 UP cornea to the pointer at the top. Now continue turning 
to the left (at the rear end) about an inch more when the mark 1-4 1-0 
will be seen. Bring this slowly up to the pointer, when the inlet 
valve should just begin to open. This can be noted by feeling the 
stem, or by placing a wire upon the top of the valve and noting when 
it begins to be pushed upward by the valve movement. If thv%%ho>M. 


happen in cylinder 4 instead of 1, turn the flj-wheel one complete 
revolution, bringing the same point to the top. If this is entirety 
correct, the flj-wheel can be turned in the same direction about 5 to 6 
inches more than half a turn, when the mark 1-4 I-C will appear. 
Turn slowly until it reaches the pointer, when the valve in cjlinder I 
should be completely closed. This can be determined again by 
feeling of the valve stem which should come down to its lowest 
position, or by the wire on the top of the valve. At this point the 
valve-tappet clearance comes in. When the valve tappet has reached 
its lowest point, and the valve has been allowed to seat, the tappet 
should go down slightly farther than the valve, leaving a very sniall 
space between the two. This is the clearance and it varies in normal 
engines from .002 inch to .012 inch. In the motor which is being 
described it is .012 inch. The closest approximation to this is an 
ordinary visiting card, which is about .012 iuch thick; when a motor 
is handled which has less, very much less, this can be approximated 
by means of cigarette pa]>ers which are very close to .003 inch thick. 
These are used in the absence of precise metal thickness gages, 
or feelers, as they are called. 

( 'alre-Sttm Clearance. This clearance is necessary to compensate 
for the expansion of the \alve stem when it becomes highly heateil 



all in good shape, this push rod adjustment is the only valve adjust- 
ment possible. If the timing is not correct, that is, if none of the valve 
operations correspond with the marks on the flywheel and the maker's 
instructions, then the cam gear has been misplaced. 

ExhausU-Valve Setting, The same procedure is followed through 
for the exhaust valve of the same cylinder, continuing past the 1-4 UP 
mark to the mark 1-4 E-0. At this point the exhaust valve of 
cylinder 1 should just begin to open. Then continue around to the 

Inlet Opens /3'' ^.OSe" 
L^e on O'rcfjmference. . 
, Inlet C/o^es 33 ■- 4. S36 
\Lohe on dn^umfierence. 
£Khou3t opens ^3 -SO'- 7353. 
Cb^lu on Circumference. 
GchoustCfoses l£''1.64Q' 
itPte an Orcumfmr^nce . 

Motor nres I'S^-2 

Fig. 163. Valve-Timing Diagram for Four-Cyli|ider Hudson Motor Indicating All Cylinders 

Courtetp of Hudson Motor Car Company, Detroii, Michigan 

1-4 El-C point where the exhaust valve of cylinder 1 is just complet- 
ing its downward, or closing, movement. If there should be any need 
for adjustment here, as described previously, this should be made 
before proceeding to the other cylinders. It should be stated that 
many makers give the exhaust-valve stems slightly greater clearance 
than the inlets, on the assumption that they work with hotter gases, 
are subjected to more heat, and should therefore expand more. The 
make being described has the same clearance for both. 

Relation of Settings in Bxich Cylinder. Now, having checked up 
and adjusted both valves for cylinder 1, follow through the saxsl^ 


process for (.'yliiider 4, and, after that, of cylinder 2, then 3, The iVia- 
grani, Fi{{. 102, sliows but tiie cycle in each cyhnder, while tJie tlescrip- 
tiiMi above simpij' listed the markings to be found on the' flj'wheel, 
so the additional diagram, Fig, 163, is given to show the relation of 
these marks to one another. This diagram refers to a different motor, 
a Hudson four-cylinder model, and the timing is indicated on the face, 
hut the repair man will understand that this is done simply for con- 
venience, and that these marks are actually found on the rim. So, 
too, the lines drawn down to the center are simply shown for con\'en- 
ience in indicating the angles and do not appear, on the flywheel. 



on each side (T-head cylinders), all in the head or half on one mde and 
the other half in the head, in short, regardless of the valve position. 
Similarly with regard to numbers, the method holds good regardless 
of the number of valves per cylinder. Moreover, it applies regardless 
of the number and arrangement of the cylinders, as it is just as good 
for eights and twelves as for the four described. On V-tjpe motors 
there is a close relation between the opposing cylinders, right- 
hand No. 1 and left-hand No. 1, and this must be taken into 
account. In some motors there is a cam for each valve, in which case 
no trouble would ensue; but in others there are but eight cams for 
the sixteen valves {of an eight-cylinder motor). This tj'pe of shaft 
will influence the timing diagram, an<l in setting, tlie repair man will 
have to concern himself with the same cam for two different valves — 


1 .B 








Fis. IAS. CidiUac Camahalt, Cun Followen. uid Coven Removed [ram Motor 

one in a cylinder of the right-hand group and one in a cylinder of 
the left-hand group. 

This statement will be more plain perhaps if reference is made to 
Fig. 164, which shows a section through the Cadillac eight for 1917, 
and indicates how the one cam operates two valves through the hinged 
rocker arms A on the left-hand cylinder and B on the right for the 
right-hand cylinder. By comparison, see also Fig, 165, which shows 
the plate C in Fig. 164 removed and turned upside down, with the 
camshaft and rockers complete. ' Not all eights and twelves are like 
this, nor do all have a single camshaft set in the middle of the V; 
on the contrary, one well-known twelve-cyhnder motor, the Na- . 
tional, has the valves on the outside of the two groups of cylinders, 
and thus has two camshafts. In such a case, the timing method just 
described would be followed through for all the cylinders on one block, 
then the same system would be followed through on the other side 
of the engine, one cylinder after another, on \hat Mock. 



Repairing Poppet Valves and Valve Parts 

The interest of the repair man in all these valve-motion part-s 13 
quite different from that of the designer, for he cares not so much 
how the;' are made as liow tiiey are taken out, repaired, and put back, 
when accident or wear make this work necessary. Tii the repair man 
suitable tools for doing this kind of work are also of interest, particu- 
larly those for reaching inaccessible parts or for doing things which 
without the tools could not be done. 

Curing a Noisy Tappet Valve springs and the valves them- 
selves, either at the scat end or at the tappet end, give the most 
trouble. For example, when the clearance between the end of the 
tappet and the end of the valve (usually from .003 to .008 inch) is 
too great, u metallic click results. Often this noise from the tappet 
is mistaken for a motor 
knock; but the skilled 
repair man has little 
trouble in finding and 
remedying if, for, even 
if he cannot measure in 
thousandths of an inch, 



rests against solid metal. The outer end can now be pressed down, 
and, with the inner end acting as a lever, the valve can be pressed off 
its seat and out very quickly. 

To make this clearer, the rod. Fig. 166, is indicated at A, while 
the dotted line shows how it is pressed down and the valve forced out. 
The garage man can elaborate upon the tool when making it for 
himself bj' using square stock; 
it has the inner end forked so 
as to bear on each side of the 
valve. The form pointed out 
above is the simplest, cheap- 
est, and easiest to make. 

Removing Valve Spring. 
Taking out the valve spring 
is frequently difficult for 
various reasons; perhaps the ^ ,«, r- ■ ., j -,- ,, ., 

' r c Pig ie7, Euily Mmdf Tno] Sot RemovinK 

springs are very stiff, or they ''■'™ spriim 

may have rusted to the valve cups at the bottom, or the design 
may not allow room enough to work, etc. At. any rate the 
removal is difficult, and a tool which will help in this and which 
is simple and cheap, is in demand. Many motor cylinders are cast 
with a slight projection, or shelf, opposite the valve-spring positions, 
so that one only needs a tool that will encircle the lower end of the 
valve spring and rest upon this ledge and give an outer leverage. 

Types of Valve Removers. 
In working on cylinders that 
do not have this cast pro- 
jection, a tool like that shown 
in Fig, 167 is useful. It con- 
sists of a yoke for encircling 
the lower end of valve spring 
and cup, with a long outer 
arm for prying, and a slot into which a drilled bar is set, Thb 
bar is placed in various positions according to the kind of motor 
which is being worked on; when removing a valve-spring kej-, the 
lower end of the bar rests upon the crankcase upper surface, or 
_upon the push-rod upper surface if that is extended. After slipping 
the grooved yoke under the spring cup, a simple pressure on VW oxAet 

Type d( Vkln.Spniia Tool WUch 
Lemva the Iluilia Free 



end raises the valve so the key can be withdrawn. Then the removal 
of the tool allows the valve spring to drop down, and the valve is free. 
The valve spring may be 
removed in two other ways by 
the use of the two tools shown in 
Figs. 168 and 169. In the former, 
the idea is to compress the -spring 
oiilj', no other part being touched. 
This tool, once set, will continue 
to hold the spring compressed, 
leaving the hands free — a decided 
advantage o\er tlie tool sliown in 
Fig. 167. This device consists, as 
the illustration shows, of a pair 
of arms with forked inner ends 
and with outer ends joined by a 
pin. A bent-handled screw draws 
the ends together or separates 
them, according to which way it 
is turned. 



double-ended wrench by means of a wire attached to the water 
pipe on top of the motor; adjusting the length of it so that the 
end of the wTench would just slip under the valve key, he was 
able to remove the pin, which freed the spring and thus the 
valve. Practically the same thing was evolved by another repair 
man who took a wrench of this type and drilled a hole through the 
center of the handle which was first twisted through a right angle. 
Then he bent a piece of stout wire into the form of a hook, one end 
through the wrench, the other over some projection on the engine. 
With the hook removed, the wrench was not radically different from 
any other and could be used as freely; with the hook in, he had a 
simple valve-spring removing tool. 

Tig. 171. Method of Comi 

Twelve-Cylinder Valve Remover. One of the objections raised to 
the twelve-cylinder motor is the trouble of removing and grinding all 
the valves. The Philadelphia Branch of the Packard Company has 
overcome this disadvantage by constructing the special tool shown in 
Fig. 171. This lifts the whole 24 valves at once. It consists of the 
central stand, which rests on the flat top of the crankcase, having a 
long arm and connected levers at the bottom to work the spring com- 
pressors. These, as will be seen at A and B, are really the special 
feature of the outfit, as they are specially constructed to fit around the 
valves in Sets of 12 each. A ratchet holds the device locked, so that 
after it is applied and fitted to all the valves, they can be forced up 
and locked ; then the matter of valve removal, regrindmg, ^n^te^^ax^Sr- 



. ment can be Iiunclle«l for the whole 24. At its conclusion, the rigging 
can be unlockctl aiul all 24 valves freed at once. 

Holding Valve Springs Compressed. Many times there is a 
need for hohllng the spring in its compressed form, as, for instance, 
when the vahe is removed with the positive certainty that it will be 
replaced within four or live minutes. In such a case a clamp which 
will hold it in compression is \'ery useful, for it saves both time and 
work. These may be made to the form shown in Fig. 172 in a few 
minutes' time, for tlioy consist simply of a pair of sheet-metal strips 
with the ends bent over to form a very wide U-shape. A pair of 
these is nia<le fur eaeli se])arate make of valve spring, because of the 
varjinj; lengths, but they are 30 
easily and quickly made that 
this is no disadvantage. 

In many shops, after getting 
in the habit of making these 
clamps, the workmen take this 
way of replacing the spring in 
preference to all others. After 
removal of the valve, the spring 



heating to a blood-red color and quenching in whale oil. If this 
is not successful, new springs are advised. 

Adjustii^ Tensktii of Valves. Unless all the valves on a motor 
agree, it will run irregularly, that is, all the exhausts must be of 
the same tension, and alt the inlets must agree among themselves, 
though not necessarily with the exhausts. Many times irregular 
running of this kind, called galloping, is more difficult to trace 
and remove than missing or some other form of more serious trouble, 
and it is fully as anno>'ing to the owner as missing would be. 

To be certain of finding this 
trouble, the repair man should 
have a means of testing the 
strength of springs ; a simple device 
for this purpose is shown' in Fig. 
1 73. As will be seen, this consists 
of sheet-metal strips and connect- 
ing rods of light stock, with a hook 
at the top for a spring balance and 
a connection at the bottom to a 
pivoted hand lever for compress- 
ing the spring. By means of the 
center rod at R and the thumb 
screw at the bottom, the exact 
pressure required to compress the 
^ring to a certain size may be ' 
determined. Suppose the spring s^. i 
should compress from 4 inches to 
3} inches under 50 pounds. By compressing it in the center portion 
of the device, so that the distance between the two adjacent strips of 
metal indicated by S is just 3) inches, the spring balance should show 
just 50 pounds. If it shows any less, the spring is too weak and 
should be discarded; if it shows any more, it is stronger than normal 
— which is desirable if all the other springs on the same en^e are 
also stronger. 

If only a quick comparison of four springs is desired, the device 
can be made without the bottom lever, as the setting of S at a definite 
figure — say to a template of exact length — would call for a certain 
reading of the scale of the spring balance. 

imrAo RigEiDiE for Tsting V 
■■ Pmaucs ud Strelvth 


Cutting Valve-Key Slots. Cutting valve-key slots in valve 
stems is another mean job which the repair man frequently meets. 
He runs across this in repairing old cars for which he haa to make 
new valves; anil at other times for other repairs. The best plan b to 
make a simple jig which will hold, guide, and measure all these thing! 
at once, as all are important. Such a jig is shown in Fig. 174. It con- 
sists of a piece of round or other bar stock, in which a central longi- 
tudinal hole is drilled to fit the valve stem, one end being threaded foi 
a set screw. Near the other end of the jig, three holes, of such a 
diameter as to correspond with the width of key slot desired, are 
drilled in from the side. These are so placed that the length from 
the top of the upper hole to the bottom of the lower gives the length 
of key seat desired. Opposite the three drilled holes and at right 
angle; to them, another hole is drilled and tapped for a set screw. 
To use the device, slip the 
valve in place and set the bottom 
screw of the jig so as to bring the 
three drilled holes at the correct 
height for the location of the key 
seat. Then the three holes are 



should, and the result is failure to discover something in the way of 
soot or dust caught in between the valve and seat, which is being 
gradually pressed into the seat, 

Regrinding Process. When either the valve head or seat has 
become worn or pitted, it must be reground aa follows; Secure a small 
amount of flour of emery, the finer the better, and mix this into a thin 
paste using cylinder oil, or graphite, or both. Loosen the valve, dis- 
connect alt attachments, remove the valve cap above, and free the valve 
in a vertical direction. Now lift it out, place a daub of the emery 
paste on the seat, and replace the valve. With a large screwdriver 

Fig. 176. Ti 

I. UnDg ft ScrewdjiTer; 

press the valve firmly in place, at the same time rotating it about 
one-fourth of a turn to the right and then the same amount to the left. 
This is shown in Fig. 175-j1, in which S is the screwdriver, V 
the valve, and VS the valve seat. Note how the right hand presses 
down on the screwdriver and turns it at the same time. While this 
is being done, the left hand should be held right below the valve 
stem with one finger just touching it. After moving back and forth 
about eight or ten times, lift the valve ofF its seat with the finger, 
turn it through a quarter-turn, and drop it back into place. Then 
repeat the grinding until the whole circle has been covered several 
times. Then remove the valve and clean off both moving member 
and seat with gasoline. Mark the seat on the valve with a sU%Kl 



touch of Prussian blue, replace the valve, and twirl it around several 
times so as to distribute the color. Remove the valve without touch- 
ing the seat portion on it or in the cylinder, and esamine both. If 
the grinding process has been complete and accurate, the color will 
have been distributed in a continuous band of equal width all around 
the surface. If not continuous, or not of equal width all around, the 
task is but partially completed and must be continued until the full 
streak results. On the first attempt at this rather delicate piece of 
work, it is well to call in an expert repair 
man to examine and pass upon the job. 
In Fig. 17.5-B the same process is 
shown, but a brace, screwdriver and bit are 
used in place of the slower screwdrivet. 
This method would hardly be advocated 
for an amateur attempting his first job of 
valve grinding, but as soon as some pro- 
ficiency has been attained, it is the best, 
quickest, and most thorough method. 

There are, of course, a niunber of toob 
now on the market for grinding valves; 



be taken up until thm is bat a fnr tboasuMhlis of an indi between 
the >-aIve tappet and the lowerendof Uienilve stem. Agoodwayto 
measure thisistoadjust nmiloDethicknessof tissue paperwill just pass 
between the two: then there bapproxiniately .008 indi between them. 

Valve Endosnres. On many oM cars, the arrangement of Uie 
valve merfianism h stkA that, aftn- se\-era] thousand miles ha^T 
been covered, the %'alve motions will become noisy and nothing that 
can be doae will stc^ this. In that ca^. the best f^u is to endose 
each one of them in a pasteboard or other tube and thus keep the 
noise in. In fact, this is _ 

a good plan even for later 
models. The method of 
doing this is indicated in 
Fig. 176, in which the 
pasteboard tube is shown 
in place around the valve 
mechanism. As this 
should be a tight 6t be- 
tween the crankcase at 
the bottom and the C}'1- 
inder at the top, the tube 
must be slit in order to 

get it on. Vkhea this 

has been done, however, 

the tube can be drawn together ^nd fastened by means of wire or 
otherwise. Besides reducing the noise, it will be found that the 
valve sv-stem parts will get better lubrication in this way and will pick 
up less dirt and dust, thus wearing less. 

Taking Out a Valve. On some engines the job of taking out a 
valve or valves is not as simple as it sounds. On an overhead engine, 
or en engine with overhead valves, it is not as hard work as on an 
engine with the valves in pockets in the side of the cylinder, for the 
overhead valves are usually set into removable seats. The latter 
come out by simply taking off a yoke or, at most, a pair of nuts, and 
then the cage and with it the valve lifts right out, spring and all. 
This latter is mentioned because with the ordinary L- or T-iead motor, 
it is the spring which causes all the trouble. Fig. 177 shows the 
process of removingthe cage and valve from an engine wvl^v ovet\iea& 

Fir 177. 


valves (this is the engine made for the Tniscott boats). To remove 
these, the valve tappet is held out of the way and the cage unscrewed. 
Troubles with Inlet Valve. The inlet valve is often the seat of the 
trouble, and missing here is generally caused by a weak or broken 
spring, a bent stem, or a carbonized valve. If the valve spring has 
lost its temper and broken down, the tension wilt be insufficient to 
property hold the valve on its seat, and the gas will partially escape 
and so cause missing. The insertion of an iron washer or two will 
increase the tension of the defective spring and serve as a temporary 
road repair. A broken spring may be similarly repaired by placing a 
washer between the broken ends. 
A bent valve stem should be 
taken out and carefully straight- 
ened by laying it upon a billet of 
wood with another block inter- 
posed between it and the ham- 
mer. Only a very little force is 
needed, and the stem should be 
repeatedly tried until it slides 
freely in its guide. 

VatveTiming Pears. As has 


to use center punch marks, one mark between the teeth on one and 
on the tooth meshing with these on the other. Then, if a second 
place has to be marked, two prick-punch marks are used in a similar 
manner, and if a third is marked, three punch marks. A third method 
is the use of numbers, the first pair marked being numbered t on each 
gear at the point of meshing, the second pair marked 2 on each, ete. 
For the second method, all that is necessary is a prick punch and 
hammer, used in the manner shown in Fig. 178. When there are but 

PIc. ITS. Method at Marking l^miiig Otan br Meuu 

two gears, as in the case shown, it is easy to make one hole between 
two teeth on one gear and another which lines up with it and as close 
to it as possible on the other gear. Where there are three, four, or 
more gears, the usual practice is to make the first and third with two 
prick-punch marks on each, the others with three, four, etc. 

For the third method, or the use of numbers, see the set of gears 
shown in Fig. 179. This figure is that of the engine whose timing 
was described and shown in Fig. 162. It has four gears; from rif^Kt 



to left they are camshaft gear, crankshaft gear, idler gear, and magneto 
gear. As will !>c noted, the crankshaft gear meshes with two othere, 
s" it must he marked in two places, 7 where it meshes with the cam- 
shaft gear ami 2 where it meshes with the idler. A moment's thought 
will show, however, that it could never be replaced in the wrong 
manner, since it is marked only on the outside face, its 7 and ;? figure.'i 
show where it matches a / mark on one gear and a 2 mark on another. 
Chain Drive for Camshafts. The silent chain has gained much 
popularity for camshaft and accessory drives in the last two years for 
a number of reasons. It saves the use of idler gears in such cases as 



Etprocket at CC. This makes its correct adjustment easy. A 
straightedge is laid across the case marks, the crankshaft sprocket 
turned to this line, and the chain put in pta^e but not joined; finally 
the camshaft sprocket is turned to the tine, the chain moved to hold 
it in this position, and its ends joined. By this method, there would 
be two possible positions for the camshaft sprocket, as compared with 
the crankshaft sprocket and line on the case. These could readily 
be distinguished as correct and in- 
correct as soon as the chain is applied 
and the engine given a couple of 
turns. If incorrect, it is simply a 
matter of lining them up again by 
opening the chain, turning the cam- 
shaft gear through ISO degrees, 
putting the chain back on and join- 
ing its ends a second time. 

Other Parts ol Valve System. 
There are a number of other parts in 
the valve group whose names and 
functions should be explained, for 
these are of interest to both the 
owner and the repair man. The 
repair man should know what work 
they do in order to be able to repair 
them successfully. Fig. ISI shows 
an overhead-valve system in which 
the camshaft is in the usual place 
in the crankcase; long push rods are 
used with rocker arms, or levers, at 
tbe top. This is mentioned because 
many, in fact the majority of, motors with overhead valves have 
an overhead camshaft like the Chalmers, Fig. 156. 

In this figure the various parts are named. The rotation of the 
camshaft brings the cam around so that it lifts the roller and plunger 
which has the adjuating screw and its lock nut at the top. The top 
of the roller bears against the bottom of the piwA rod, and the 
upper end of the push rod operates the valve rocker lever which is held 
in the support. At the other end of the valve tockei Wvei s. loUer 


presses against the top end of the valve stem and pushes it down from 
off tlie talce sent against the pressure of the spring, the upper end 
of which is held by the cup and cup pin and the lower end rests 
upon tlie upper surface of the value cage. The latter is made so 
that its central upward extension also forms the mlve guide. The 
valve cage is screwed down into the cylinder head with packing to 
make a gas-tight joint. It carries the value seat and is cored out for 
the gas passages through which the gas enters (or leaves). 

When the valve in pockets is substituted for the long push rod, in 
either the L-head or in the T-head cylinder, the construction is about 
the same as if the upper right-hand valve group were lifted bodily, 
turned upside down, and placed so that the upper end of the valve 
stem, upon which tlie roller rests, comes into contact with the adjust- 
ing screw. In that case, the 
valve lifter would be called the 
push rod, and .the valve cage 
would bectHnea part of the cylin- 
der with an integral or, in some 
cases, a removable valve guide. 
Push Rods and Guides. As 
? seen from Fig. 181 and 

gasoliKe automobiles 


the yoke that rests upon shoulders on the push rods and holds them in 
place. From a repair man's point of view, the latter construction is 
better, for the push rods can be removed and replaced much more 
easily and quickly. 

Valve Cage Repairs. When the valves are in overhead cages, it 
is highly important that they fit tightly in the cylinder head; they 
must be ground in as carefully and as tightly as the valves are ground 
into their seats. Where a shop handles a good many motors of the 
overhead-valve tj-pe, it is desirable to make a rig to do the grinding 
easily. One of these rigs is shown in Fig. 183. It consists of a shaft 
and handle with lock nuts for 
the valve cages used on Buick 
cars. On these cars, it is in two 
parts; the cage proper, and the 
lockingmemberwhich screws into 
the cylinder. Obviously the cage 
is the one to be ground in. The 
rig shown slides in the central 
opening, that is, fits in the valve 
guide, and has a lock nut top 
and bottom to fasten it tightly. 
When fitted into place firmly, the 
right-angle bend in the rig gives 
a handle by means of which the 
cage can be lifted in and out and, 
what b more important, rotated 
on its seat. When the cage is 
prepared, the seat is given a little oil and emery or oil and powdered 
glass or prepared valve grinding composition, the cage is set in place 
and ground in the same as a valve, that is, with one-third to one-half 
rotations in one position, then lift, move around, and repeat in the 
new position, continuing this until the whole surface of the cage in the 
cylinder has been covered twice. This should result in a good seat. 

When the valves in an overhead motor need grinding, the valve 
and cage are taken out completely and held in an inverted position 
io a vise or other clamp, and the valve ground In to the seat in the 
cage in the regular way. It is said this can be done very rapidly and 
well by chucking the valve stem, as it projects from \.\ie c&f^, \u «. 


lathe rotating at a very slow speed, and operating the cage by hand, 
that is, shde the cage back, apply grinding conipoiind, then move the 
cage up to the rotating valve and hold 
it with tlie hand while the valve is 
turniug with the lathe. In holding it 
tlma, the pressure endwise should be 
very light. 

Valve Guides. The valve stem 
must be a tight fit in the guide, other- 
wise air will leak through into the 
combustion chamber and dilute the 
mixture, or the compression will leak 
out, or both. Any valve leak will affect 
the running of the motor, so it should 

F\f IM NIrlli.H! of Carina \■^h■e- ^ Stoppcd at OUCC. TwO methods of 

uidt L^Bh tjiurkiy rnij c tapiy temporarily remedying small leaks are 
shown in Figs. 1 84 and 1 85. A simple leather washer with a small hole 
through the center, which fits tightly over the valve stem, is pressed 
up around the outside of the guides, as shown in Fig, 184, This 
simple re[mir was very cfl'ecti\'e, and the leather washers lasted an 


wearing surface. This len^ and the need for accuracy through- 
out makes the valve-guide bole an awkward surface to repair. 
When worn beyond any hope of simple repair, it ia best to ream it out 
and press in a bronze bushing so that the valves can still be used. 
An excellent tool for this purpose, developed for Dodge motors but 
which is usable for almost any motor, is shown in Fig. 186. This con- 
sists of a high threaded bushing which is clamped to two diagonal 
cylinder studs. The thread inside the bushing is very fine. A long 
tube, with the lower end bored out to take a standard reamer, is 
screwed into it. The top is squared and a handle is made to fit it. 
When the handle is turned, the 
tube is gradually screwed down 
into the cylinder, carrying the 
reamer slowly but truly down 
through the valve guide. This 
rigging is simple, easily made, and 
gives accurate results. When 
the valve-guide hole is reamed, 
the bushing can be turned up 
and pressed in with any form of 
shop press. 

Valve Caps. The plug which 
fits into the top opening in the 
c>'liiider through which the valve 

L is put in place and removed is 

' called the valve cap. Sometimes 

I it has external hexagonal sides 

I so it can be easily removed, but 

. more often it has an internal hexagOn, or internal ribs. The 
latter form can be removed most easily by constructing a special 
tool, consisting of a cylindrical member, with a bottom diameter 
slightly larger than the opening in the valve cap, with four (or 
more) teeth, or projections, set into the bottom of this to match the 
ribs inside the cap. A central hole is drilled for a bolt with spark- 
plug threads at the bottom. To use the member, remove the spark 
plug, set the device in place, slip the central bolt in and screw it down 
into the plug to hold the whole thing in place, then apply a 
wrench to its upper square surface and remove the valve, cap sni^ t^. 

_ .IT Reunina Out Vahrv 
^Ira Guide Hola 
run 'tf Motor IKorU" 



It can be laid aside just as removed, and when the work is concluded, 
the whole thing can be screwed back in, the central screw loosened, 
and the rig removed from the cap. 
Sometimes the threads in tb* 
cylinder into which the valve cap 
screws become dirt\, slightij' cul 
up, or marred so that the cap docs 
not screw in or out readily. Bv 
taking an old valve cap of the same 
motor and same threads and fluting 
these in a milling machine, as indi- 
cated in Fig. 187, a neat tap can 
be made which will clean out the 
Thrtrirfm.f \iiK<Tup threads in a Hffv. It is simple, effcc- 

tive, and cheap. 
Cleaning Camshaft Gears. On tlie majority of engines, the cam- 
siiaft and other gears or the silent chain which replaces them, are lubri- 
cated automatically by the running of the engine as they are by-passed 
in on the engine lubricatinp; system. This is an exc'cllent feature. but 
it leads to ncplcct. These gears or sprockets are sure to wear, and 



Twisted Camshafts. With the present form of camshaft having 
the cams forged integral, troubles and irregularities between one 
cylinder and another, which the repair man finds difficult to trace or 
run down, sometimes develop in the running of the engine. A fairly 
light camshaft will sometimes become twisted, usually right 
at a cam where the stress is. When trouble of this kind is indi- 
cated, the camshaft should 
be removed and tested. A 
good way to do this is to 
place the shaft in the milling 
machine with the index head 
set so that one revolution of 
the shaft can be divided 
into four equal parts. Place 
a thin disc in the arbor, 
then mount the shaft and 
bring it up to the disc. 
Choose one of the cams and 
set the disc to the exact 
center of the j)oint of it. 
Then, by turning the shaft a 
quarter-turn each time, the 
other cams can be tested with 
their relation to this one. 
Sometimes a difference of J 
inch will be found in this 
way. "Hie lay-out for this is 
seen m Fig. 188. 


A method of avoiding cams, and with them all cam troubles, is 
the use of a sliding sleeve in place of a valve, slots in the sleeve cor- 
responding to the usual valve openings, both as to area and timing. 
The sleeves may be operated by means of eccentrics by various lever 
motions, or by a direct drive by means of agear mounted on a separ- 
ate shaft. 

Qear ControL An example of the application of a worm and 
gear for this purpose to a French two-cycle engine is dwwnv Sa, 


Fig. 189, althougli there is nothing in its construction which would 
prevent its. use on the more usual four-cycle engine. 

In this figure, P is the usual crankshaft, Q the large end of the 
connecting rod A', while A is the piston and R the crankcase, no 
one of these differing from those in other engines. On the tTankshaft 
there is a large gear F, which drives a smaller gear E, located on a 
longitudinal shaft above and outside of the crankcase. On this shaft 
is located a worm gear D, which meshes with a worm C formed inte- 
gral with the sleeve surrounding the piston B. Aside from this worm 
gear, the sleeve is perfectly cylindrical, being open at both ends. It is 
placed outside of the piston, between that and the cylinder walls. 
At its upper end, it has a number of ports, or slots, cut through it, 
which are correctl\' located vertically to register, or coincide, with the 
port openings in the cylinder wall when the sleeve is rotated. One 
of these is seen at //; the exhaust, while 90 degrees around from it, 
and hence invisible in this figure, is a similar port for the inlet. As 
the crankshaft rotates, the side shaft carrj-ing the worm is con- 
strained to turn also. This turns the worm which rotates the worm 
wheel on the sleeve. In this way, the openings in the sleeve are 
brought around tn the proper openings in the cyHnder, and the com- 



actuated from a regular camshaft — nmning at half the crankshaft 
speed and driven by a silent chain— by means of a series of eccentrics 
and connecting rods. In the figure, A is the inner and longer sleeve 
and carries the groove or projection C at its lower end. The collar 
actuating the sleeve is fixed around and into it. This collar is 

fit. 19a WiOya-Koiaht Engii 

Cuds utA Vilva 

Sliding aiccvOB Replun 

■ttacbed to the eccentric rod E, which is driven by the eccentric shaft 
shown. TTie collar D performs a similar function for the outer 
sleeve 5. 

At tlie upper ends of both sleeves, slots G are cut through. 
These stots ate so sized and located as to be brought into cottwA. 


Royal Automobile Club's Committee Report on Knight Engini 

. . 124 by 130 

, .3805 lb. 
. .4085 lb. 
..134 hours IS n 

!! Five— 116 min, 



. .5 hours 15 tnin 

Molor horsppower — R. A.C. , . . 

Bore and stroke , 

Minimum horsepmver allowed . 

Speed on bench test 

Car weight on track , 

Car weight on road 

Duration of bench teat 

Penalized bIodh 

Non-penulizcd stops 

Light load periods , 

Avfirage horsepower 

Final bench teat 

Ponalized stops 

Light load periods 

Average liorsppower 

Mileage on track 

Mileage on road. 

Total lime on track 

Average tratk speed 

Fuel per brake horsepower per hour 

Car miles per gallon ton Irack. . . , 

lOn road. . . . . 

Ton miles per gallon |On track , ,. 

\On rood. . . .. 

22 85 

Sflby 130 


1400 r.p.m. 

3332.5 lb. 


132 hours 58 a 

Two— ir min. 
41 min. 

45 hours 32 n 
42.4 m. p. h. 
First bench 

.079 pt. .739 pt. 

.613 lb. .6681b. 

.599 pi. .749 pt. 

.541 lb. -6771b. 

20 67 22,44 

19.48 19.48 

34.94 33-37 

35.97 31.19 



e surfaces of the valves are grooved at <7 to produce proper distribu- 
D of oil. 

The Knight type of motor has been adopted by a number of 
U-known firms in America, such as the Steams, Willys, P. R. P., 
jwster, and Moline Companies. These engines are noted for 
lir silent running and for their efficiency. The Moline-Knight 
■tor was subjected to a severe continuous-run test of 337 hours, 
der the auspices of the A. C. A. authorities, in January, I9I4. 
iring this time the motor developed an average of 38.3 brake horse- 

Slwves Which Replaced Valve* 

137-Hoiir Bench Teet 

. I Knuht E _ _, 
d 220O MUa on the Road 

ffer. During the 337th hour the throttle was opened, the motor 
j^eloped a higher speed and a brake horsepower of 53. After the 
t, the motor parts showed no particular evidence of wear. The test 
es abundant evidence of the endurance and reliability of the sleeve 
ve tj-pe of motor and of the sterling qualities of the product of 
' American automobile manufacturers. 

In addition to the four-cylinder forms just mentioned, the 
ight type- of motor is also made as a six, and, more recently, as 
'-type eight. In these forms, the basic principle of sliding sleeves 
1 their method of operation and timing is not changed. 



Originally', the Knight motor was installed only in the highest- 
class cars. The firms in Europe which took it up ranked among 
the very first — notably the Daimler, Panhard, Minerva, etc. — but 
in this country it has made little progress among the better care. 
It is now assuming the rank of a low- and medium-priced motor, being 
available for about $U)(H), and as an eight, for approximately $2000. 
Timing the Knight Motor. While the connection between the 
Knight motor sleeves and eccentric rods, and between the rods and 
the eccentric shaft, is more or less permanent, there is the possibility 
of the shaft being bent or twisted during running or dismounting. 
The repair man should know how the motor is timed, in order to cor- 
rect any faults. As will be noted 
in the timing diagram shown in 
Fig. 192, this is not radically 
different from the poppet-i-alve 
tj'pe. The Inlet opens at 6\ 
degrees past the upper center and 
closes 45 degrees past the lower 
center, a total opening of 2t8i 
agrees. The exhaust opens 40 


Inlet ^ena Intel Open Intel Cloaea CompreaaionSlreke, 

Posttignl Posiliene F0silian3 Position^ 

Rt- 163. Varioua 8U(« in Cycle of Knisht BUdios-SlMve Motor 


is beginning to open, the inner sleeve has reached the top of its move- 
ment and starte<l down, while the outer ia almost at the top. At 6 
the exhaust port is fully ojien, tlie slots register exactly with each 
other and with the cyHnder outlet, both sleeves are traveling down, 
the outer having reached and passed its highest point. At 7 the 
exhaust has just closed, the inner sleeve has reached its bottom 
position and is about to start up, while the outer sleeve is close to the 
bottom. The cycle of inlet, compression, explosion, and exhaust 
has now been completed and is about to start over. Note that 
position 7 is almost exactly like position /, but a slight additional 
movement of the sleeves is needed to produce the latter. 

The eccentric rods are very similar to connecting rods, as will be 
noted by referring back to Fig. 19!. Here E is the eccentric rod 
operating the inner sleeve C, while D is the eccentric rod which oper- 
ates the outer sleeve B. As will be seen, these have an upper end 
exactly like a piston, or wtIsI pin, except that no bushing is provided. 
At the lower end, it will be noted that the fastening and arrangement 
is just like the big end of a connecting rod. It should be cared for, 
adjusted, anti tiglitcned in just the same way to get the best results. 



Roberta Rotary Valve, A motor — a two-cycle motor, by the 
way — which has been very successful in motor-boat and aeroplane 

Fic. 194, Ri 

work, although not much used for motor cars, is the Roberts, shown 
in Fig. 194, with the valve in Fig, 195. This valve is for the inlet 
ports only and is located inside the crankcase, while the cylinders 


exhaust freely into the open air, the exhaust issuing directly from 
the cylinders. 

Inqmrtance of Handling Exhaust Oases Properly. In all that 
has been said previously on the subject of valves no mention has been 
made of a specific form of valve, everything applying equally to the 
inlet or the exhaust type. Under the subject of carburetors, the inlet 
manifold has been considered in detail. So far, nothing has been said 
of the exhaust gases and the method of handling them. Generally 
speaking, the matter of handling exhaust gases in the past has been 
done with the smallest possible amount of time, trouble, and thoii^ht. 
They had to be gotten rid of, so it was done as easily and ^vucVi:] «% 


ls engines got larger and larger, and as speeds increased, 
there was more and more gas to handle. The growing cTy for a quiet 
or a noiseless car necessitated giving the problem more thought, for 
the simple appHcatioii of a muffler did not entirely eliminate the noise. 
As fuels grew heavier, heat was required to assist in tlie process of 
vaporising. In order to apply heat, many designers began to see 
possible uses for some of the gas pouring out at the rear end of the car. 
Todaj', the handling of tlie exhaust gases is probably being given as 
much thought as any part or unit on the entire car. 

Forms of Exhaust Manifolds. Ordinarily the exhaust gases 
emerge from tlie cylinders into the exhaust manifold. This is gen- 


has the outude valves, so the exhaust manifold is located there. It is 
a typical cast-iron manifold, differing from the ordinary manifold 
only in having the outlet at the center instead of the rear end. Six 
bolts hold it in place; four on the upper edge, and two on the lower. 
Its interior structure is evidently the same throughout, and no special 

provision has been made for reducing gas friction. It has no attach- 
ments of any kind. 

Many exhaust manifolds have been cast integral with the cylin- 
der block; this method is quite popular among small car makers, as it 
is used as mudi to save the expense of machining and fittmf^ uv& \iq 



reduce the weight and number of parts as for any other reasons. 
In the larger sizes it probably never will become popular, because of 
the difficult core work in the foundry which makes cylinder-casting 
cost prohibitive, and thus more than offsets any other saving. 

A number of manifolds have been cast with cooling fins, or flanges, 
on the outside, the effect being to reduce the exhaust heat immediately 
by dissipatiun ; a secondary idea is that of making the casting stilfer 
and stronger and less liable to loss by breakage. A flanged manifold 



of gas to be handled, the speed at which it had to be handled, and the 
necessity for silence called for a separate exhausting system for each 
group of cylinders. These were problema, aside from the fact that it 
was more simple structurally to handle the exhaust in two manifolds. 
A double-manifold construction is shown in the Cadillac, Fig, 198, 
which is a view of the rear end of the engine. The two manifolds 
for the two sides can be seen readily; also the two separate exhaust 
pipes, wrapped with asbestos where they pass the dash and other 
wooden parts. A further view of this car is shown in Fig, 199, the 
chassis from above, in which the two separate systems can be fol- 
lowed back to the mufflers Just forward of the rear axle on either aide. 
Muffler. The purpose of the muffler is to reduce the pressure of 
the ftascs by expansion to a point where they will emerge into the 
atmosphere witiiout noise. This is generally done by providing a 
numlxT of concentric chambers; the gas is allowed to expand from the 
first pjiKSJijre into tlie much larger second one, then into the still lai^r 
third one, and so on, to the final and largest passage, which is con- 
nected to the pijje leading out into the atmosphere. This is not as 
simple as it sounds, for, if it is not well and wisely done, there will be 
back pressure which will reduce the power and speed of the engine, 



. ' 

— ) 

t * i 


t.vpe. Cone-iihaped baffles whicli force the gases to expand and then 
pass through ven' small apertures and expand again form the ba^ of 
E. This is the si>-t-alled ejector t j-pe, the passage of the gases from the 
large to the small end of the various cones being supposed to create 
a suction behind it which draws the gas out from the exhaust pipe 

Muffler Troubles. When the engine mjsteriously loses power, 
it is well to lo<jk at the muffler. A dirty muffler fiUed up with oU and 
carbon, which results from the use of too much oil in the motor, will 
choke up the passages so that considerable back pressure is created. 
When this is suspetteil, tap the muffler aU over hghtly with a wooden 
mallet, and the exliaust gases 1^ill blow the sooty accumulations out. 

Cut-Outs. Formerly, the majority of cars were equipped with 
muffler cut-outs, liy pressing the foot on the button operating the 
cut-out, the engine was allowed to exhaust directly into the atmos- 
phere, cutting out the muffler. It sensed as a warning signal ; it gave 
a good means of checking up the firing of the various cylinders; and 
several years ago, it nas supposed to give greater power. Since its 
use was overdone, many cilies and state;* prohibited such an arrange- 



Water-Jacketing. The first essential in water-cooling a motor 
is to provide the cylinders with water jackets, through which the 
cooling water is circulated in contact with the outside of the walls 
within which the heat is liberated. 

Water jackets are of two tj^pes, integral and built-up. The latter 
3\"5tem of construction, though adding to complication and conducive 
to leakage, permits of lighter construction, besides diminishing the 
likelihood of hidden flaws in the cylinder castings, which, with cored 
jackets, are not likely to reveal themselves until they cause a break- 
down, perhaps after the engine has been long in use. 

Integral Jackets. With integral jackets, the usual system is to 
form the jackets by cores, in the founding, so that there are no open- 

Els.201. Detailed View of Csdillu CrUnder Chwii 

ings in the jackets except those for removing the core sand and wires 
and for connecting the pipes of tlie circulating system. In many of 
the best examples of motor design, howe\er, the core openings are 
left very large but with plane faces, and are closed by screwcd-on or 
clamped-on plates, thus making tlie construction practically a 
compromise between the completely integral and the completely 
built-on jackets. 

For example, in such modem construction as that shown in 
Fig. 2, a large plate will be noted on the ends of the cylinders. This 
covers a tremendous core hole, by the use of which the internal 
construction of the water jackets is made practically perfect in the 
foundry. This also allows easy inspection and cleaning, the removal 
of the two end plates enabling a person to see right through tbe ^».\JW 


jacket from end to end. This latter-day construction overcomes all 
objections previously raised against troubles with complicated water- 
jacket cores. A detail of this cylinder block, showing clearly the 
arrangement of the cikI plates, the water passages around the cjlin- 
der bores, and other points, is presented in Fig. 201. The designers 
of large block castings for cylinders were forced to provide for easy 
inspection of this kind for self-protection, although in this connection, 
it is no more than fair to state that foundry men have made just as 
rapid advances in the art of casting automobile-engine cylinders and 
other complicated parts as the designers of machines have made in 
every other wa,\\ 

Hmlt-On Jackets. There are a number of forms of built-on 
water jackets, but few of these are in use at present. The best of 
these was the old Cadillac jacket, a cyhndrical one-piece member with 
a junk ring, top and bottom, to hold tightly against water leakage. 
The form mure often used is the applied plate, or sheet, which must be 
held b\- s<Te\vs, llanges. or clamps. As these are not really success- 
ful in holding the water contuiuously, particularly against the com- 
bination of hot water, internal pressure, twisting, and nicking action 
which ojnios from tra\eling over bad roads at high speeds, they are 


obtain sudi a combination at a reasonable cost. So far, however, 
it has been restricted to racing cars, in which the lightest possible 
weight is obtained regardless of cost. In a car to sell at an ordinary 
price, the cost might be prohibitive. 

Radiators and Piping. It has often l>een pointed out that all 
cooling of automobile engines is, in realit;-, air cooling; the water- 
cooled motor is simply one in which the heat units to be disposed 

Studeluker Cut 

of are coifveyed from the cylinders to the radiator by the circulating 
water, to be dissipated in the air that passes through it, instead of 
directly lost in air passing over thin flanges cast on the cylinders. 
A water-cooling system therefore constitutes a sort of indirect-air 
cooling. This being the case, the chief justification for water cooling 
consists in the margin it allows for much greater cooling areas in 
contact with air than it is possible to provide by mere extensions of 
the cylinder surfaces themselves. 



A tj'pical pleaRureH?ar radiator of the tubular type is shown m 
Fig. 202. As will he nnted, the flanges have a continuous horizontal 
appearance, but the vertical tubes which carry the water can be seen 
in the background. These actually carry the water; the horizontal 
flanges simply serve as a heat-radiating surface. This type is rapidly 
increasing in popularity for pleasure cars of medium and low price, 
at the expense of all others. 

The total cooling area of the radiators employed io automobiles 
will range all tlie way from ten to ninety square feet; the latter 

Secliai of Filler 


a motor that may have run for months without any cooling trouble 
whatever in level eountry will often hoil all the water out of the 
cooling system within a few minutes. 

Tppei of Cell*. In the cellular, or honeycomb, radiator, there are 
three forms of tubing in general use. These forms are: the square, 
with its flat sides set horizontally and vertically; the round, with the 
tubes staggered so as to make the number as large as possible; and 
the hexagon, which is also set staggered so as to use the maximum 
number. The square and hexagon are more used on pleasure cars. 

Fig. 204. Beoault Foi 

while the round form has been used on higher-priced motor trucks. 
A modification of the round-tube form is found in the radiator which 
utilizes the plain cx)pi>er tubes, bunched and fitted into a header, or 
water tank, at the end, but which are not formed into a composite 
unit. This is used on both pleasure cars and trucks. 

Types of Tubes. In the tubular form, there are two well-known 
types: the round vertical tube with spiral fin, or flange, welded or 
sweated on; and the so-called tube-and-plate construction, shown in 
Fig. 202, in which a set of horizontal plates is pierced with a. nucoAtet 



of holes, tubes set into these, and the whole dip-soldered into a unit. 
The former t.Npe is gaining rapidly for truek use on account of its 
freedom from leakage under the severe racking conditions of truck 
use. An example of this t>pe is to be found in Fig. 203, which shows 
a. welded tubular radiator. It is of interest to note that the welded 
tjpe replacetl a soldered honeycomb unit of the highest quality which 
could not be kept water tight in war service. 

Modifications of Cellular and Tubular Fonns. In addition to tlie 
types shown in Figs. 202 and 203, there are a mmiber of forms which 


Another modification abng somewhat simUar linra, whidi isused 
For a truck, is that shown in Fig. 205. This fonn consists of an upper 
tank, a small lower tank with the outlet, and a connecting group of 
xpper tubes. It is made in the form of a circle of the largest possible 
diameter the tube structure will allow and of a width equal to the 
depth of the bank of tubes. The fan is placed in its immediate 
:;ent«r. By placing the radiator at the rear end of the engine, the 
fan can be driven directly from the crankshaft or the flywheel, which 
^ves the fan a higher speed. The unusual size and high speed of the 
-'an circulates an unusual amount of air around the bare copper tubes. 
I^opper is the best radiator of heat known except silver. On a truck, 
'.he position of the radiator at the back of the engine is held to be 
I big advantage, because the 
;ntire cooling system is protected 
rora the frequent and unavoid- 
ible collisions of truck service. 

The piping of automobile 
»oling systems in a great many 
ars is made too small to afford 
-'ree circulation, and this mistake 
D design, common in the earlier 
lays of automobile engineering, 
3 one that cannot be too carefully 

tvoided. n*. 20e, Oev Type of WMw Pump ol 

, . ^ Very Simple Coxutruetioo 

In the expenence of most 
lutomobile designers, the most satisfactory method of connecting 
ip the piping of a circulating system is found in the use of ordinary 
steam hose, clamped around the ends of the pipe by small metal 

The use of steam hose for practically the entire piping system 
s considered an improvement over the short hose connection by a 
few designers. It does away with metal piping altogether except as 
it extends from the radiator and water jackets for the attachment of 
the hose. 

Circulation. An unobstructed and vigorous circulation of the 
rater in a cooling system is a great factor in reducing the size of 
radiator required and in preventing overheating and boiling away 
)f the water. 


Pumps. The usual method of circulating the cooling water !s 
to use one type or another of small pumps, driven by suitable gearing 
from the engine itself. 

Gear pumpsare often used for thiapurpose because of their extreme 
simplicity, but it is difficult to make them large enough to handh. 
as great volumes of water as most designers now regard desirabW 

A good example of the gear form of watur pump is shown 'm 
Fig. 206. This is simply a. pair of gears which mesh rather closely^ 
the movement of the flat side of the teeth carries or forces the watet 



simple multi-bladed "impellers" revolvioj^ with close clearances in a 

One advantage of the centrifugal pump is that if any small 
object, such as a stick or pebhie, should by any chance get into the 
circulating system — though strainers always should be provided to 
prevent this contingency — no serious harm is likely to result, whereas 
with a gear pump breakage is almost certain to ensue. 

The construction of the centrifugal form can be seen in Fig. 207. 
This is not as clear as it might be because the impeller is sectioned at 

Coolini u Used an Overlnod Can 

the point where the water chamber is largest; in short, at the water- 
outlet space. The impeller fits the casing very closely except at 
the water outlet where the water is thrown off by the centrifugal 
force generated in rotation. The centrifugal form of pump is also 
fairly well illustrated in Fig. 210, where it will be noted that two of 
them are used on the two ends of the upper shaft. 

Chiefly in motor-boat motors of the two-cycle types, recipro- 
cating plunger pumps are used to circulate the cooling water. The 
volimie of water handled by pumps of this type, of dimensions that 
can be conveniently employed, is not very large, however, and it is 



only the fact that the water is not Fe-used and is, therefore, cooler 
and of a consequently greater effectiveness that makes possible the 
use of plunger pumps in motor boats. 

Thermosipkon. Circulation of the cooling water by the thermo- 
siphon action, owing to the heated water in the jackets rising and the 
cooled water in the radiator descending, is the practice of an increas- 
ing number of designers, and has been demonstrated to be very 
effective with liberal jacket spaces and large-diameter piping. 

The pioneer, and still the most prominent exponent, of thermo- 
siphon cooling is the Ilenault Company, of France. A t^Tiical 
Renault nmtor-inid- radiator combination with thermosiphon cir- 
culation is illustrated in 
Fig. 204. 

A better example of 
the thermosiphon sys- 
tem, that is, a drawing 
which shows it much 
better is Fig. 208. In 
this the large open pipes 
with few bends,* and 



certain figure at which the thermostat is set, it comes into action and 
cuts off the flow of water from the radiator to the pump. The result 
is that the pump can circulate only that part which comes through 
the very small pipe to the inlet manifold and carburetor and from 
there back to the pimip. This continues until the water becomes 
heated; the raising of the temperature oj^rat-" the thermostat whicli 
opens the valve, and the s>steni n agum (.■()m[ilete. In the upper 

right-hand part of this figure, the circulating system of one block of 
cylinders is shown in outline. 

The method of controlling the temperature of the engine with 
an automatic check valve is receiving much attention; there is even 
talk of extending the same system of control to the exhaust gases and 
all sources of heat, interconnecting them with the fuel vaporizer so 
as to vaporize the maximum amount of fuel in the minimum time with 
the least heat loss. The tl\ermostat and pump combination used on 
the Packard twelve-cylinder motor is shown in Fig. 210, in which it 
will be seen that two pumps are placed on the pump shaft, one at 



each end so that the thrust of each one balances the other. In the 
Cadillac, the two cyhnder groups are separate, each having all the 
units shown in Fig. 209 except t^e radiator. Id both the Cadillac 
and Packard systems, the thermostat is placed at the bottom of the 
system. It has been advocated by engineers for other companies 
that this would do the most good if placed at the top of the system. 

The value of a thermostat may be gained from these figures. 
One particular make of thermostat, as used on a popular make of car, 
was tested out with the following results: Without it, the car did 
14) milt» on a gaUon of fuel at 15 nLpJi. and 13} miles at 30 m.pJi. 
At the same speeds and with the thomostat set at 160 degrees, 
the same car under the same circumstances did 16} miles at 
almost 15 m.p.h. With everything the same but with the device set 
to work at 180 degrees, the car did 19} and 16} miles, rapectivdy. 
The gain at the lowest speed of 15 miles an hour from 14} to 16} and 
then to 19} miles per gallon represents gains of almost 14 and 3ft 
per cent in economy. 

Fans. In the earlier days of autconobile deigning it waa 
deemed sufhcient to secure drculation of air through the radiaton 
by the movement of the car alone. This was soon found inadequate 


must pass through the center where the fan is located. This is but 
another way of saying that all air must pass through at a high 
velocity, which insures eflSciency. This plan fulfills one requirement 
of air cooling, that is, the large quantity of air which must be used. 

Where this system is used now, the entire engine in front of the 
fan is made air tight. The hood, which has no openings anywhere, is 
set into .carefully fitted rubber strips to cut off any possible leakage. 
The same precautions of drawing all the air through the radiator, 
and through that alone, are observed elsewhere. While this method is 
eflFective, it is a disadvantage in another way, for some direct cooling 
is effected through the cylinder walls, exhaust pipes, etc., in the 
ordinary system by the cold air passing over the radiator, particularly 
the air which comes in from around the hood top and sides. 

Anti-Freezing Solutions. In using automobiles in very cold 
climates during the winter months, there is great danger of the water 
in the cooling system freezing when the car is standing still, or even 
with the motor running slowly if the temperature is very low. The 
result of such freezing is almost certain injury to the cylinders, 
through cracking of the water jackets, as well as the probability of 
bursting out radiator seams, with consequent leakage. 

To avoid these difficulties it is not uncommon to use, instead 
of piu^ water, one kind or another of anti-freezing solution, usually 
compounded by the mixture of some chemical with water to lower 
its freezing point. Thus, glycerine or alcohol mixed with water will 
keep it from freezing at all ordinary winter temperatures. Glycer- 
ine is somewhat objected to because of its sticky, gummy nature, and' 
also because of its deleterious effects upon the rubber hose of the 
piping system. Alcohol, if not replenished from time to time, will 
evaporate out of the water and thus permit it to freeze, or, if mixed in 
too great a quantity, it may introduce a fire risk otherwise avoidable. 

A much favored anti-freezing solution consists of calcium 
diloride dissolved in water, in a quantity proportioned to the tem- 
peratures that it is desired to guard against. 

All anti-freezing solutions are more or less objectionable in that 
they are more likely than pure water to corrode and clog up the cir- 
culating system, and there is no doubt that the elimination of the 
necessity for them by the substitution of air cooling for water 
cooling will mark a great advance in automobile development. 




Though successfully' employed in on6 or two automobiles and 
remarkably tle\'eloped in some of its applications to aviation motors, 
air cooling is not considered by most engineers to be successfully 
a|>pIicabIo to the average automobile. That it will become more 
practical in the future, however, is the opinion of many. 

I'nfortunatcly, this is an instance where the better and. simpler 
method does not meet with popular approval, that is, the cooling 


Air Jackets. Several of the most practical examples of air- 
cooled motors in aviation construction are those which have, in 
addition to the flanges, or fins, on the cylinders, air jackets to concen- 
trate the drafts of air that effect the cooling. 

Blowers and Fans. The most successful air cooling has been 
accomplished by types of blowers capable of inducing much more 
vigorous air currents than are drawn through the radiators of water- 
cooled automobiles by the types of fans commonly used in power 
plants of that character. 

In the Franklin, the most successful air-cooled automobile 
motor, a side view of which can be seen in Fig. 211, the cooling is a 
sort of combination of the flange and the blower method. The fins 
are vertical and radial, with a close-fitting hood connected to an air- 
tight pan. At the only opening in this hood, which is at the rear end, 
is placed the fan (on the fl^nvheel). This draws the air past the 
cylinder walls, where it is needed. 

Infernal Cooling and Scavenging. Perhaps more promising as 
a road to final and universal use of air cooling are the systems of 
pumping air through the interiors, instead of blowing it over the 
exteriors, of the cylinders. Such internal cooling, in addition to 
directing the maximum cooling effect where it is most needed oh 
the oil-coated surfaces that are exposed to the heat of combustion, 
has the further advantage that it may be made to scavenge out all 
residual exhaust gases, which, besides helping to accumulate heat, 
also act so detrimentally upon the functioning of ordinary motors. 
This is a direct result of the admixture of retained exhaust gases 
with incoming fresh charges. 

Methods of internal cooling and scavenging that appear of 
. definite promise are those proposed in various recent schemes for 
pumping air first into the crankcase — either by using the under side 
of the piston as a pump, as in common two-cycle constructions, or 
by applying special pumps to the crankcase for this particular pur- 
pose — then into the cylinders by means of by-passes, with the result 
that it exerts a positive cooling effect inside the cylinder. 

In England, some interesting experiments have been made on a 
theory of internal cooling in which water is introduced into the 
cylinders in the form of a spray, at certain points in the cycle. This 
is said to add power in addition to helping the cooling. 


Cleaning. It ia highly important that the cooling sj'atem be 
entirely cleaned out at least once, and preferably twice, a year. What 
this is done, the water jackets and radiator should be flushed out witi 
a strong current of water, preferably a hot soda solution. Tliia should 
be forced through in a direction opposite to the usual course of thft 
water. Thus, a hose can be put in the radiator filler cap and city 
pressure applied to force the water through ; in this radiator, it will be 
made to go from bottom to fop instead of the usual top to bottom. 
If this method, which is the usual and easy one, does not remove aDi 
dirt, sediment, and foreign matter, the radiator can be removed and 
boiled, or at least submerged, in a strong soda solution which wiH, 
clean it out thoroughly. The radiator is the most important member 
of the system. 

Replacements. When thia is done, it is advisable also to look 
over all hose and hose connections. Many times the liose will have 
become worn or frayed through and cut or otherwise damaged fron 
the outside, or the water may have attacked it from the ttiside, par-- 
ticularly if it has been through a winter when an anti-freezing 
solution was used. It is well, when cleaning the system, to replace aU 


others need the application of a pointed tool and hammer to tmn 
it. In the latter case, do this very carefuity so as not to chip off 
any metal. OccasionaUy, the fan bearings need adjustment or lubri- 
cation. When they are of the plain type, a grease cup is generally 
provided, and after the engine is stopped, a couple of turns of thia 
will be sufficient. If of the ball or roller type, they will be packed in 
grease, and if they show signs of running dry, the fan should be taken 
apart and the grease renewed. Use a good grade of cup grease for 
this purpose, not a hard grease. 

Adjusting Puiiq)5. Generally, the pump is made so as to need no 
adjustment. However, a leak may occur at one of the packing nuts. 

To remedy it, tighten the nut as far as possible, but if this does no 
good, remove the nut and add packing under it. Special packing is 
provided for this purpose, but if no other is available, a thick heavy 
piece of string can be well coated with graphite or a graphite grease 
and wound on as packing. In putting on packing of this kind, it 
should be wound on right_handed, or in the same direction as the pack- 
ing nut turns to tighten. Otherwise, tightening the nut will loosen 
the packing. 

304 Gasoline automobiles 

The Ford motor circulation is of the tliermosiphon order, but 
often, for one reason or another, it does not do well, so the motor con- 
tinues to heat, although everj'thing appears in good condition, fan 
belt tight, etc. For snch cases, an additional means of circulating 
the water is needed. There are several devices on the market, one 
consisting of a form of screw set into the water pipe with the idea of 
stabilizing the flow of water. Another, Pig. 212, uses the force of the 
exhaust gas by-j^asaed through a small special pipe into a nozzle 
of the ejector type placed in the water inlet to cylinders to make 
the water flow more rapidly and evenly. It is said that this uses but 
3 per cent of the exhaust gas and that it is designed to keep the 
water sj'stem working at 195 degrees, which is a very efficient point, 
more power being developed at temperatures approaching the boiling 
point than at low temperature. In addition to improving the water- 
circulating system, this device is said to eliminate carbon formation 
and save 20 per cent of the fuel and oil. 

In general, the cooling system is an easy one to take care of and 
repair because such a large part of its units and components are fool- 
proof. Moreover, it is a system which gives visual and other evi- 
dences of derangement. 


up, which can be checked by disconnecting, or else the circulating 
pump is not working properly. All modern engines are so propor- 
tioned that, in this event, the water continues to circulate by thermo- 
siphon action. Taking off the pump will verify this. 



When the lubrication system is referred to, that of the motor is 
generally meant. Motor lubrication is of the highest importance; 
for the motor must have efficient and continuous lubrication to run 
properly. Taken in its broadest sense, however, the title should refer 
to the entire lubricating means of the car; that is the way it will be 
handled here. The other units and parts of the car may not need as 
efficient or as continuous means of lubrication as the engine, and the 
presence or lack of lubricant is not so tremendously important; but all 
of it is of value and influence in the operation of the car, and should 
be well known. 

Interior and Exterior Demands. The engine of a motor car 
requires two distinct kinds of lubrication. The interior parts, which 
are subjected to the greatest heat, rotate or slide at the highest 
rate of speed, and generally do the greatest amount of work, must 
have what amounts to a continuous stream of good lubricant. With 
the exterior parts, which do not rotate so fast, do less work, are not 
subjected to much heating, and will be kept cool by the atmosphere, 
there is no need for this continuous stream, nor for such a quantity 
or high quality of lubricant. 

The exterior and interior systems must be considered sepa- 
rately. With reference to the internal oiling, there are two general 
systems in use : the pressure form, and the splash type. A third, which 
is now coming rapidly into use, is a combination of the two, called the 
splash-pressure system. For 1917, the relative popularity of these 
three is as follows: pressure, on 30 per cent; splash, on 35; splash- 
pressure, on 35. 

In the pressure form (or its modification, the splash-pressure), 
the pressure may be produced in a number of ways: by a single large 
pump; by a series of small pumps, one for each bearing lead; or by a 
reservoiTi or tank^ kept filled by a separate pump (gravity ptessvise^ . 


Splash-Pressure Feeding. One of the best and most successful 
tj-pes of liil>ri(.'ittion systems is that in which the oil is fed under 
pressure to tlic (Ufforcnt bearings. 

In tile s|)lasli-pressurc system, the oil to all the crankshaft and 
coiinectiiig-roil bcariiifis, to the timing gears, and to the upper portion 
of tlie cylinder walls is supplletl through the medium of a gear-oil 
piniip driven usually by worm gearing from the camshaft. The other 
bearings within tlii' engine are lubricate*! by oil spray tlirown from 
the crankshaft. Sut-li a system is shown in Fig. 213. 

Orerhinil. Tlio same units .are necessary in all splasli-pressure 
svstenis, Init they can he and arc used in widely different ways. It 


From here it passes back through the pipe D to the inner distributing 
pipe E; Has serves to keep the troughs FF, filled. At the middle part 
of the downward stroke, the scoop on the bottom of each connecting 
rod dips into its own oil reservoir and splashes up a fine spray of oil. 
At high -speeds, the four rods fill the whole interior of the crankcase 
and the lower parts of the four cylinders with a mist of oil. This is . 
sufficient to lubricate everything thoroughly. In a system of this 

. kind, the strainer is of great importance and must be kept clean. 
Sinailarly, the oil sump should be drained very frequently, at least 
every 1 OCX) miles. 

Studebaker. The Studebaker system is very similar, except that 
the oil pump is outside of the crankcase and set higher up. It is of 
the simple gear t^pe and is not liable to derangement. The system 
is equipped with an oil-level indicator on the side of the case, which 
shows the quaotity within the case. 



Single-Pump Pressure Feeding. The drilled crankshaft, as 
shown in Fig. 21.'5, is a necessity in all pressure systems, as it also n 
in all combination splaah-pressiire systems. This can be seen, and 
perhaps the whole system explained more clearly, bj' referring to 
Fig. 215, In this the single pump working direct is used, tlius differ 
ing from the reservoir s\'stem explained above. This diagram shows 
also how the oil is forced to flow through the three bearing leads to 


Generally, pockets are provided inside the motor to catch the 
mist and force it to flow to the camshaft and other bearings besides 
the crankshaft, but in this case it will be noted that the camshaft 
bearings have individual supplies through the medium of a camshaft 
oiling pipe. 

An objection to lubricating systems of this type is that in case 
there are several leads to different bearings one of them may become 
obstructed without anything to indicate this condition or to over- 
come it until the bearing involved becomes overheated and ruined. 
If one lead becomes obstructed, the oU can still continue to feed-Odt 


through the others, thus relimng die piuaauit m i 
Donnsl maoDer and failing to levol a anious d 

Sieanu. The Steams-Kni^it tyttem is ahown in fff. 218. 
The oil 19 circulated by s pump (not visible in this iketcli) at the 
^nt end of the eccentric shaft 2). After paamig thrau^ a suua 
and the pump, it is forced tbnx^ a etrainer A in the filter E, thenee 
through pipes to the pump-ehaft bearing eccentric-Aaft chains 
and main crankshaft bearings. It readies the csankshaft bearings 
throu^ the oil inlet F, the drilled boles in the oankdiaft bong indi- 
cated at G. From these holes, it icadus the bidloir cater ol die 
connecting rods K, andthustothefMstonpinsandp 
At the bottom of each connecting rod, there are time mat 
holes through which sufficient oil escapes to lubricale the i: 
outer sleeveswhich take the place of the valves. A gage ou tbc da^ 
board, or cowlboard. indJcatca the oil pressure and should read t. 
1 to 5 pounds with the throttle closed and the motor idling, 
from 40 to 60. pounds when the throttle is wide open and the t 
running normally or at high speed. 

Regulator Connectwl to Throttle. Tlie variation on this pre 
sure is controlled entirely by the liy-pass in the main oil lead, which 



On high-speed ami multi-cylinder motors (which are almost 
invariably high-speed forms), the lulirication assumes an importaace 
not hitherto attatrhed to it. This is ros[M)ii:jibIc for the pressures used 

ami for the wide spread use of mecliaiiically driven jiositive pumps. 
Formerly, pressures of from a few ounces to 4 or 5 pounds were con- 
sidered sufficient. Now, pressures as higli as 00 and 70 pounds are 
not unusual. These trcnien<lous pressures, hi>wever, have necessi- 


tated a sj'stem much more carefully constructed, assembled, and used 
than was the case previously. 

Mannon. The Marmon system is not radically different from 
that just described, but there are a nimiber of small Individual points 
worthy of mention. The filling is not through the usual crankcase 
breather pipe, but through an opening in the top of the cylinder head 
t, Fig. 217. From this opening the oil flows around the valve push 
rods (the motor had overhead valves as will be noted) down into tbe 
bottom of the oil pan 2. After 
screening at 3, it passes 
through the throttle-controlled 
regulator to the oil pump 4 on 
the rear end of the camshaft. 
The main feed pipe is marked 
5, the pressure gage 6. lead to 
crankshaft bearings 7, hollow 
in crankshaft S, connecting-rod 
bearing 9, cylinder waits 10. 
ball check valve / / to govern 
pressure in main feed pipe 





a cam, and in a few cases the vane pump. While essentially the same 
as the forms used for pumping water described previously, they are 
smaller in actual size and have some few different details. In the gear 
form, which is shown in 
Fig. 219, one gear b driven 
directly from the engine and, 
in turn, drives the other, 
their rotation foreing the oil 
along in the direction of 
rotation. Usually a by-pass 
with a check valve is pro- 
vided, and when the pipe 
is obstructed or the pres- 
sure rises for any other rea- 
son, this opens and the oil passes around the pump at low pressure, 
equalizing the system. 

The cam-operated plunger form is shown in Fig. 220. This is 
the method of drive adopted for mechanical lubricators, but few 
engines have an individually con- 
structed pump of this type. It is 
simple, easy to regulate, seldom gets 
out of order and can be arranged to 
give a different supply at each plunger 
should the system warrant or necessi- 
tate this. A good example of the 
plunger form is the oil pump on the 
Reo engine, shown in Fig. 221. This 
works as follows: When the pump 
plunger A is moved upward by the 
curved eccentric B, it draws oil through the ports C and the screen 
D, as the entire lower part is submerged in the oil. When the max- 
imum amount of oil is drawn into the pump chamber in this way, the 
plunger descends, the ball E rises, and the oil flows up inside the 
hollow plunger to the top ports F, through these to the surrounding 
chamber O, and thence to the outlet H and into the oil pipes. This 
fonn is very accurate and reliable. 

Meihoda qf Driving Pumps. Another point of considerable 
imptvtaace to the repair man is the method of driving the pump, 

d Pluncer 




since this influences its location and its accessibility. There are but 
two general methods of driving. One is by means of a special oil-pump 
shaft, in Ti'hich the pump will 
quite K<'nerally be found in the 
bottom of the oil sump or very 
close to it; the other is from 
some part of a shaft used for 
other purposes, in which case 
tile position may vary widely. 
Examples of thefirst.orspccinl- 
shaft method, will be seen in 
Overland, Fig. 214, and Cad- 
illac, Fig. 215. Examples of 
the second method are seen in 
Stearns, Fig. 216, and Mamion, 
Fig. 217, in both of which the 
camshaft is used. 

In Fig. 222,agear b placed 
directly upon the rear end of 
the camshaft meshing, with 





on the camshaft. It projects out at right angles on the side between 
cylinders 2 and 3. It is possible to arrange a system of this kind so 
that an extra cam is not needed, one of the regular valve cams doing 
the work of pmnping the oil. This makes s simple and inexpensive 
arrangement. The oil suction pipe is marked B and the pipe carry- 
ing the supply to the bearings is marked C. Attention is called to the 
connecting-rod oil scoops D, the feed adjustment E, the pressure- 
relief valve F, and to the main oil lead G. 

Individual Pump Pressure Feeding. The expedient of feeding 
the oil by individual pumps, independently driven and capable of 
individual adjustment which enables them to feed any desired amount 
of oil to any par- 
ticular bearing re- 
gardless of the 
amount that may 
be fed to any other 
bearing, has been 
widely applied. In 
such a system, if j 
obstruction of any | 
one of the leads 1 
should occur, it is 
almost certain to be 
forced out by the 
action of the pump, 
which, in all lubri- 
cating systems of established tj^ie, is made capable of working against 
enormous pressure. 

One of these lubricators, made for eight feeds, is shown in Fig. 
224. By extending the casing and the longitudinal shaft inside and 
adding more pumps, thb tv-pe is capable of extension to any desired 
number. The eight-feed form shown allows of one lead to each of the 
three main bearings of a four-cjlinder engine, one each to the four 
cylinder walls, with a lead remaining for the gear case at the front 
of the motor. 

Gravity Feeding. Feeding of oil by gravity to one or more bear- 
ings 13 a method that has been employed with some auCcess, but it is 
now encountered only in rare instances in autMnobile power ^lantft. 



^lash Lubrication. The feeding of oil to bearing surfaces by 
the simple expedient of enclosing a quantity of it in a resen-oir in 
■ which the working parts are also contained is a successful and widely 
used scheme in automobile motor construction. 

In the splash lubrication system, as will be shown in detail later, 
the lower ends of the connecting rods "splash" up the oil which is in 
the bottom of the crankcase in the form of a huge puddle. Since thb 
method, formerly' almost universal, has been criticised as wasteful <rf 
oi! as well as i)ru<luctive of much needless smoke, it has been modified 

. Ili;it tilt- scix.p 
iirroiv trouylis \i 
sti-m is tliJit at 

FiK. 22.V Ty,«.-.,] S. 
Typr (irraw f.ip *i 

by the majority of tnakci 

ncctinf; rods dip into snui 

Another objt't-tion to thi: 

is thrown iirouuil tlie interior of tlii 

the initini rotation of the r(«ls has 

supply into a mist, whih' at low s|H' 

for the work the engine is doing. 

The latter olijVction has tiei-u o\ 
mnkiiig tlie trouglis into wliieli the 
able and attin-hed to the throttle le 
o|x-ned wide to develo]) niii\ininm jxi 
higher, allowing tlie .-icooiis to dip d 
greater amount of hibrieaiit. 

External Lubrication. In the hibrieatioii of the external parts 
of the motor, such as the pump shaft, magneto shaft, oiler shaft, faa 

in the ends of the cor- 
1 for this purpose. 
It at high .speecls t«)o little oil \ 
■yliiiders and crankcase, since I 
■hnnied or Iwaten the entire \ 
s too much is thrown arountl 

come in the newer engines b^' 
niie(tiiig-ro<l scoops dip mov-' 
T. s(. that when the latter i=* 
!T, tlie tnmglis are brought ufF 
rn dtt'iKT and thus supply a 


shaft, generator shaft, air pump shaft, etc., an entirely different 
method of lubrication is necessary — one that is more simple in every 
respect, allows the use of more simple lubricating devices, and does 
not require anything like the care and adjustment previously pointed 
out for the internal parts. 

Oil and Grease Cups. Chief among the devices used for lubricat- 
ing these outside parts are oil and grease cups, the oil cups being used 
in decreasing quantities and the grease cups in increasing quantities. 
Formerly, oil cups were much used, but they gave poor satisfaction, 
collected dirt, and were unsatisfactory generally. In the use of 
grease cups, there are but three things to observe: They should be 
large enough, accessible, and easy to fill. 

For application to spring eye-bolts there is a particular type 
of grease cup. This grease cup is of the type that feeds by being 
occasionally screwed up a small distance as the bearing uses up the 
lubricant, and its positive action is rendered more certain by the use 
of a detent (not illustrated) that holds the cover in any position in 
which it may be left. The grease is contained in the entire cap which, 
when imscrewed from the lower portion, is readily and conveniently 
filled by scooping up the grease. 

A form quite generally used is the simple cup shown in Fig. 225. 
This is a screw-compression cup from which the lubricant is forced out 
by screwing down on the reservoir. This form is prevented from com- 
ing loose by the compression spring, here shown very much compressed 
below the ratchet, which governs the screwing down of the reservoir. 
To fill the reservoir, the ratchet portion is held down and the top 
screwed off, turning in the reverse of the usual direction. Although 
the top is fitted with a wing handle, it can hardly be considered easy 
to refill. 

Another widely used form is seen in section in Fig. 226. This has 
a larger handle and, in this respect, may be considered easier to fill. 
A t>T)e which is rapidly coming into use and has all the advantages of 
the other two, and more, is shown in Fig. 227. This is a plain 
screw type with a large handle, but the cap is of sheet brass and 
is spnmg into place. As this is sprung off by the plunger inside 
when screwed away out, filling is reduced to a matter of sec- 
onds. The plunger screws all the way in and affords pressure all 
the way. 



Splash Lubrtcalion. The feedinK of oil to iH^aruif; surfares hj- 
the simpip expedit-nt of enclosing a quantity of it in a reservoir in 
■ which the workitiR parts are also contained is a successful and widely 
used scheme in automobile motor construction. 

In the splash lubrication s>-stem, as will be shown in detail later, 
the lower ends of the connecting rods "splash" up the oil which is in 
the bottom of the crankcase in the form of a huge puddle. Since this 
method, formerly almost universal, has been criticised as wasteful of 
oil as well as productive of much needless smoke, it has been modified 


shaft, generator shaft, air pump shaft, etc., an entirely different 
method of lubrication is necessary — one that is more simple in every 
respect, allows the use of more simple lubricating devices, and does 
not require anything like the care and adjustment previously pointed 
out for the internal parts. 

Oil and Grease Cups. Chief among the devices used for lubricat- 
ing these outside parts are oil and grease cups, the oil cups being used 
in decreasing quantities and the grease cups in increasing quantities. 
Formerly, oil cups were much used, but they gave poor satisfaction, 
collected dirt, and were unsatisfactory generally. In the use of 
grease cups, there are but three things to observe: They should be 
large enough, accessible, and easy to fill. 

For application to spring eye-bolts there is a particular type 
of grease cup. This grease cup is of the type that feeds by being 
occasionally screwed up a small distance as the bearing uses up the 
lubricant, and its positive action is rendered more certain by the use 
of a detent (not illustrated) that holds the cover in any position in 
which it may be left. The grease is contained in the entire cap which, 
when imscrewed from the lower portion, is readily and conveniently 
filled by scooping up the grease. 

A form quite generally used is the simple cup shown in Fig. 225. 
This is a screw-compression cup from which the lubricant is forced out 
by screwing down on the reservoir. This form is prevented from com- 
ing loose by the compression spring, here shown very much compressed 
below the ratchet, which governs the screwing down of the reservoir. 
To fill the reservoir, the ratchet portion is held down and the top 
screwed off, turning in the reverse of the usual direction. Although 
the top is fitted with a wing handle, it can hardly be considered easy 
to refill. 

Another widely used form is seen in section in Fig. 226. This has 
a larger handle and, in this respect, may be considered easier to fill. 
A type which is rapidly coming into use and has all the advantages of 
the other two, and more, is shown in Fig. 227. This is a plain 
screw type with a large handle, but the cap is of sheet brass and 
is sprimg into place. As this is sprung off by the plunger inside 
when screwed away out, filling is reduced to a matter of sec- 
onds. The plunger screws all the way in and affords pressure all 
the way. 


Oils and Qreases 

Characteristics of Good Oils. The variety of oila aod greases 
recuniineiitled for automobile use is so extensive, and there are sii 
many cheap and worthless lubricating compounds on the market, 
that it is almost impossible for the purchaser without technical knowl- 
edge to discriminate between them. The various tests from time to 
lime recommended, whereby the user may ascertain for himself the 
quality of the lubricant he is using, are rarely of positive value, sine* 
the compounders of the shoddy oils and greases are usually sufficiently 
expert chemists to concoct admixtures that will successfully pass 
such simple tests as are a^'ailable to the average layman, and will fail 
only under the more critical analysis of a competent chemist, or under 
the se\ere and more risky practical demonstration that results from 
long use, in the course of which the worthtessness of the lubricant is 
likely tii be found out only at the cost of serious injury to the 
mechanism. The consequence is that the only really safe policy to 
fiilluw is the |)urchase of the highest grades of oila and greases, 
marketed by concerns of established reputation. 

Tiic oils generally found best for gasoline-engine cylinder lubri- 
cation aic tlic mineral oils derived from ]>etroleuni. though castor 


admixed in very small percentages with cylinder oib, gearbox greases, 
etc., there is no question but what it greatly conduces to smooth 
running and to long life of bearings. Its resistance to the very 
highest temperatures makes it constitute a considerable safeguard 
against immediate injury in case of neglect to replenish the lubri- 
cants as often as is properly required. 

Testing Oils for Acid, Etc. Oils must be purchased with much 
care. Once an oil is found which does the work satisfactorily, it 
should be adhered to consistently. No two oils are exactly alike, and 
for that reason, no two will do the same work under the same condi- 
tions in the same way. So, it is advisable to experiment only until 
an oil is found which will do the work. Thereafter, stick to that 
brand. As an instance of the impurities which may be found in oils, 
acids may be mentioned. These are fatal to delicate and closely 
machined parts, such as ball bearings, cylinder walls, pistons, etc., and 
consequently they should be watched for. 

Pure mineral oils contain little acid, and what they do contain 
is readily determined. Vegetable and animal oils, on the other hand, 
all have acid content and under the action of heat this mav be lib- 
erated. A simple home test may be practiced as follows : Secure from 
a druggist a solution of sodium carbonate in an equal weight of water. 
Place this in a small glass bottle or vial. To test an oil, take a small 
quantity of the lubricant and an equal amount of the sodium solu- 
tion. Put both in another bottle, agitate thoroughly, and then allow 
it to stand. If any acid is present, a precipitate will settle to the 
bottom, the amount of the precipitation being a measure of the 
amount of acid present. 

Another method is to allow the acid, if there is any, to attack 
some metal. To do this proceed as follows: Soak a piece of cloth or, 
preferably, wicking in the oil suspected of containing acid. Select a 
piece of steel at random and polish it to a bright surface. Wrap the 
steel in the soaked rag or wicking, and place in the sunlight but 
protect it from wind or weather. Allow it to stand several days, and if 
there is no sign of etching of the surface, repeat with a freshly soaked 
rag, being careful to use the same oil as before. After two trials, 
if no sign of the etching appears, you may consider it free from acid. 

Principles of Effective Lubrication. To render lubrication 
positive and effective there are certain conditions regardviv^ \k^ 


design of bearings anH the fee'Iing of lubrimtits that must be scru- 
pulously observed. 

The proper applieiitiim of a lubrieant to a revolving sli.ift 
passing through a bearing requires that definite space be provided 
between shaft and bearing for the lubricating material. The amount 
of this space varies with the size of the shaft, the speed of rotation, 
and other conditions, but in a general way it can be specified that 
tlie space must be greater as the shaft diameter incTcases, and greater 
for Iieavy oils and low speeds than for light oils and high speeds. 
For the crankshafts of automobile engines, to take a specific example, 
it is rarely desirable to have the bearing smaller than from .0(10.5 
to .0015 inch larger than the shaft. The annular space thus pro- 
vided, as suggested at A m the end and sectional views in Fig. 229, is 
occupied by tlie lubricant, which, coutrarj' to another general impres- 
sion, will not be squeezed out unless the shaft is loaded above its 


times erroneously supposed, but to provide an oit film of the necessary 
uniform, instead of an irregular, thickness. 

Care of Lubricant in Cold Weather. Nearly everyone realizes 
the amount of- care necessary with cooling water in freezing weather, 
but few realize that extreme cold has practically the same effect upon 
lubricants. In the coldest weather, a lighter grade of oil specially 
made to withstand low tempera- 
tures should be used. If a 
special oil cannot be obtained, 
the lighter thinner quality will 
suffice, as even when thickened 
up by the low temperatures this 
oil will flow more readily than 
the thick oils. Sometimes the 
slow circulation of the oil in cold 
weather allows the motor bear- 
ings to run dry and heat. This 
trouble can be remedied by 
changing to a lighter oil. The 
same is true of the clutch oil 
which is in the multiple disc n 
running in oil. Thick oil in this 
in cttld weather will often thicken 

up and stick so the clutch will Flg-WO. Munnmth Gnur Cud ror Cunce Vh 
, ,, CoartavB/ ■Molar JTbtU" 

not work well. 

Mammoth Qrease Qun. For the average shop which handles a 
good many cars a day, too much time is wasted in using an ordinary 
method of filling a transmission, rear axle, or other lai^ part, with 
grease. A mammoth grease gun can be constructed to do this same 
work in a few seconds. A form operated by compressed air is shown 
in Fig. 230. It consists of a steel cylinder about 8 inches in diameter 
and perhaps 7 feet long mounted vertically on a platform which is set 
on castors so that it can be wheeled around the shop as needed. A free 
piston is placed in the cjlindcr, abo^e the grease, and air admitted 
through the central opening in the screw top by screwing on a com- 
pressed air hose. The outlet hose at the bottom is made lou% 


enough to rearh any ordinarj' point on the average car. When a 
transmission is to be filled, the platform is wheeled up to the car, 
the bottom hose put in tlie transmission, and the cock opened. Then 
the air hose is coniiectt.'d and the pressure turned on; the grease will be 
forced out in a hurry, filling the case in a few minutes regardless of 
the quantity nee<U'd. A somewhat similar device can he made in a 
smaller size. This de\icc is almost an exact copy of the ordinary hand 
j^rease gun, but it has a rod, threaded 
through the cap, which operates the 
plunger. Oneman can hold the gun while 
another turns the handle, which forces 
out a tremendous quantitj' of grease in a 
short time. 

Oil Tank and Outfit for Testii^ 
Bearings. A tank for testing the leakage 
of bearings, particularly engine b 
that are loose, may be constructed by 
fixing in the top of a small tank a gage 
which will read up as high as 20 pounds, 
an inner-tube valve stem for sup- 

AruuiT Oi^ 



grouped ova a small pan which catches the drip. Filling these 
barrels is easier than it seems. Simply coimect a pipe from the 
barrel of new oil to the 
overhead barrel to be 
filled, apply the air pres- 
sure carefully at the 
bung, and the oil will 
be forced up. 

A more simple 
method of covering and 
protecting the barrels is 
to have a box, or stand, 
large enough for three or 
more barrels, made from 
light lumber. Then bore 
a small hole, at the place 
where each barrel will n,. 232. Method of ei. 
stand, for the faucet, as couhov «/ ■ M,aor woru- 

Fig. 233 shows. Generally, three barrels will be sufficient, as one 
for heavy oU, one for light oil, and one for kerosene will cover all 
ordinary work. The shelf 
which holds the various 
measures should be at- 
tached to the frame. 

A convenient oil- 
drain rack in the form of 
a small square box, say 
6 to 8 inches deep, can be 
made with tin. Punch a 
series of small and me- 
dium size holes in the top 
of the box. When the 
funnel has been used for 
filling an oil tank or meas- 
ure, it can be placed in the 
rack and allowed to drain. In this way, oil waste is minimized and 
the place is kept free from oil drippings, which soon gather dust and 
then are tracked into office and customers' cars. 

Fi(. 233. Eamly Coutnictcd Bo: _. 

Protdctinc Oil BattbU 
Cinritti Bf " Moler Wvid" 


Oil Settling Tanks, 

as imtli mauufiictuRTs ii 

If lubricating sj-stems are drained as often 
Till oil people recommend, there is a good deal 
of oil around, which is heavy and of a doubt- 
fnl quality. But if this oil can be allowed 
to stand, op can be filtered, a large quantity 
of it can be used for other purposes. If a 
tank of fairly large size is made with a series 
of faucets or cocks at different levels, some- 
what like that shown in Fig. 234, enough of 
the oil can be saved to resell at a good profit, 
or, if there is no idea of selling it, it can be 
used for other machinery' or for other pur- 
poses, where the need for high-quality oil is 
not so great. The oil drawn off the crank- 
case is poured in at the top and gradually 
*''*cS»Brv'ii'rio''u-.'L."v(i"''" settles, the heavier sediment going to the 
bottom, the thickest oils next, and so on, 
until the top will sliow a fair quality of light oil, and the layer next 
to it a fair quality of medium oil, and so on down to the bottom. 
Oil Filtering Outfit. 



two or three bunches of waste will lose practically all its impurities, 
coming out perfectly clear. After each use, the waste is removed 
and burned, and new waste put in its place. 

Oil measures, funnels, and other containers should always be kept 
clean. The oil left on them soon collects dust and dirt, and the next 
time some of this old oil will be poured into the engine with the fresh 
oil. Ail oils do not mix, and chemical action may be set up 
between old oil of one quaUty on the can and new oil of another 
quality in the can. Kerosene or a little gasoline should be poured 
in the containers or funnels to clean them off. This liquid 
should be rinsed out of the cans and put into a settling or filtering 
tank and practically all of 
it recovered. ['\ ji^jub. 

Bending Oil Pipes. 
Frequentjy an oil pipe 
which has a curve or spiral 
in it, or even a series of 
coils has to be replaced. 
If bent by hand, a kink 
may be made in the pipe 
which will lead to a future 
break. A simple fitting 
for bending these pipes can be made in a few minutes. Take a piece 
of hard wood about .3 inches square and 9 inches long and turn it 
up round in the lathe, then down one end, as shown in Fig. 236, and 
cut the spiral grooves or threads in it. These shouki be about ^ 
inch in width and cut with a round-nosed tool so as to get a smooth 
bottom to the grooves. When a pipe is to be bent, fill it with resin, 
a fine lead rod, or anything flexible. The wood can be held in the side 
of the vise and the tubing wound onto the threaded end. If the 
pipe is of a heavy gage, anneal it by heating and plunge it into cold 
water before starting to bend it. 

Summary of Troubles with Lubrication Systems 

Crankcase Oil. This should be changed about every 500 miles as, 
by this time, the lubricating qualities of the oil are nearly exhausted. 
After draining the oil, wash out the crankcase with kerosene and 
see that the kerosene is removed before putting in fresh oil. 

Fw 230. Hud Wood Fiiture fat Bendinc Oil Pipe 


( ;AS( tLINE AUTl )M( JBILKt^ 

Grease Cups. These are usually Incateti on the rear axle, steer- 
ing knuckles, stt'erinfr-tiilumn base, and many other parts. They 
should be kept foiistantly filled with cnp grease. These grease cups 
should not be confused with small oil holes having caps which can be 
raised but not unscrewed. Grease cups should be screwed down 
occasionally in order to force the grease down to the bearing surface. 

Neglect of Lubricalion. Neglect of lubrication is responsible 
for many troubles. An\' automobile requires careful attention to its 
lubricating system. The owner will find it to his advantage financially 
to see that all necessary parts are properly lubricated. 

Steering Gear. The steering-gear parts require occasional lubri- 
cation. TJiese parts include steering rod; worm, or sector, and gear; 
steering link at both ends; foot-pedal pivot or bearing; and all joints. 

Too Much Oil in Crankcase. Usually drain cocks are provided 
in the crankcase and are so located that when they are opened 
they will drain off only the surplus oil. 

Troubles with Mechanical Lubricator. If one of the sight feeds 
fills with oil, it indicates too rapid feeding of oil. Shut ofT the valve 
on the tup of the lubricator till the glass is clear. !f it does not 
clear up shortly, the probability is that it is nece.ssary to clean the 


ball bearings. The other shafts, as pump, oiler, magneto, air-pump, 
generator, etc., are generally of the plain, solid, round t^^je. 

Engine bearings, however, are generally of the split, or halved, 
type, the upper and lower halves being practically duplicates. A 
reason for this construction appears as soon as one considers the 
application of the bearings to the shaft. It is granted that a crank- 
shaft must be as firm and solid as possible, and hence it must be made 
in one piece. As ball bearings also are made in one piece, there arises 
at once the difficulty of getting the bearings into place on the one- 
piece shaft. This difficulty has necessitated cutting the shaft or else 
making it especially large and heavy in those cases where balls are 
used. With the split type of bearing there are no troubles of this kind 
and the bearings are adjustable for the inevitable wear. 

Plain Bearings. The conditions that determine the proper 
proportioning and fitting of plain bearings have already been referred 
to in a preceding paragraph. 

The materials of plain bearings are commonly varied to meet 
different conditions. With liberal bearing areas, in situations where 
it is desired to bring about a perfect fit with the minimum amount 
of labor, and to protect the shaft from wear in case there is failure of 
the lubrication, the various types of babbitt metal — which usually 
are alloys of tin and lead, with sometimes some admixture of antimony 
and other alloys — are widely regarded as the most serviceable. Prob- 
ably the greatest advantage of a babbitted bearing is that, if the 
lubrication should fail, the low melting point and the soft material of 
the bearing will insure its fusing out without injury to the more 
expensive and valuable shaft. 

Brass and bronze bearings, particularly the phosphor bronzes 
and the bronzes in which the proportion of tin is high and that of 
copper low, with sometimes the admixture of a proportion of zinc 
or nickel, will allow the use of materially higher pressures per square 
inch than can be safely permitted on babbitted bearings. 

Steel shafts 'in cast-iron bushings, and even in hardened-steel 
bushings, make much better bearings than one might think, and 
though immediate trouble is to be anticipated with such a bearing 
should its lubrication fail, even momentarily, this trouble is more or 
less true of any bearing that can be devised. Since steel-to-steel and 
steel-to-cast-iron permit much the highest loadings per unit of are;i 


that are permisaible with any type of metal-tometal bearing, the 
merits of tliese materials are perhaps less appreciated than might be i 
desirable. Steel pins through ateel bushings, however, we noc an 
uncommon construction for the piston-pin bearings in hi^i-gnuk 

One noticeable feature of plain brouEe or other plain \ 
for automobile use is that they are always grooved for oil c 
This is done by easing off the edges, then cutting a spiral gioowtgr 
hand diagonally across to the other edge or to the center point iriMnS 
similar groove from the other side is met. In a solid bearing, ijbs 
groove is generally cut both ways horn a centrally drilled (ul hafi, 
while in split bearings the grooves in each half usually form a modilad 
letter j- when viewed in plan, that is, two grooves start spirally inward 
from each edge near the ends, and all four meet in'tfae center. "Daa 
central point may be the spot where the oil enters or where it leaves; 
These grooves are seldom of very great depth, periiaps .OOS to .010 
(eight to ten thousandths). 

\ew OUkss Bearings. A form of bearing that is new to the 
uutumubilc but old in years is now coming into use. This is made of 


und accurately to size. This type of roller tain be depended 
■ work without breakage or injury even though there be con- 

c deflection or iiuiccuracy in the alignment of shaft or casings, 
ibility of tlie individual rollers taking care of such small errors. 

vill be noted in Tig. 2:i!S that tlicrc is a solid .steel shell to go on 
t and fit it tightly, aixl an<)th('r to (it into the case or support, 
jr it may be, perha|>s attachwl there iiernianeiitly. Between 


tbi'5e two comes the cage cairrjing the flexible rollers. Any load 
imposed upon the shaft is transmittet! to the inner sleeve and bv 
it to the flexible rollers ; these rollers absorb the load so that none of it 
reaches the outer case. Furthermore, shocks coming to the case 
from without are absorbed by the flexibilitj' of the rollers and, riw 
tersa, shocks to the shaft do not reach the case. 

Ball Bearings. Probably the best of all bearings, except for 
c-ertain special applications in which it is difficult to utilize them in 
sufficiently large sizes to assure durability, are the annular ball 
bearings of the freneral type illustrated in Figs, 239 to 243, inclusive. 
The basir fciiliirf nf the most successful of modem annular ball 
bearings is their non-adjustability, the 
balls being ground very accurately to 
size and closely fitted between the 
inner and outer races so as to allow 
practically no play. 

The reason that the best ball bear- 
ings are not made adjustable is that in 
any conceivable Xy^ of ball bearing 
one or the other of the races rotates 
.nd the other remains in a fixed 



The carrying capacities of ball bearings, as compared with those 
of roller bearings, are much greater than a casual consideration might 
lead one to suppose. Theoretically, the contact of a roller bearing — 
between a roller and one of the races — is a line contact, while that 
between a ball and a ball race is a point. But, practically, since some 
deformation occurs in even the hardest materials under sufficient 
load, the line contact in the roller bearing becomes a rectangle and the 
point contact in the ball bearing becomes a circle. Now the vital 
fact is that the area of the rectangle in the one case is substantially 
equal to that of the circle in the other — ^with given quality of materials 
and a given loading. So a ball bearing is fully as capable of carrying 
high loads as a roller bearing; besides, it avoids the risk of breakage 


Fig. 241. Ball Cage of Annular Ball Bearing 

that usually exists with rollers because of the impossibility of making 
them perfectly true and cylindrical. 

To assemble ball bearings of the type illustrated in Fig. 240, either 
of two expedients may be adopted. One is to notch one or both of 
the ball races, so that by slightly springing them a full circle of balls 
can be introduced through the notch. The other scheme is to employ 
only enough balls to fill half of the space between the races, which 
permits them to be introduced without any forcing, after which they 
are simply spaced out at equal intervals and thus held by some sort 
of cage, or retainer, -such as is illustrated in Fig. 241. 

Ball bearings of the common annular type are quite serviceable 
to sustain end thrust as well as radial loads. For the best results 
under such loads, however, it is essential that the load be distributed 
equally around the entire circle of balls, for which reason the system 


illustrated in Fig. 242 is a means of avoiding the unequal distribution 
of pressure likelj' to result from the slightest inaccuracy of fitting. In 


Tliruat Loula 

this construction the outer ball race, shown at A, is provided with 
a spherical outer surface, permitting it to rock slightly in the mount- 
ing r, into the position shown in an exaggerated degree at B. It 
thus floats automaticiilly to a position at exact right angles to the 
ihaft upon which it is mouiitedt 
and so insures even loading of 


Combined Radial and Ttirust Bearing. The need for a bearing 
which would take ordinary radial loa<^s well and also sustain thrust 
has led to the development of combined radial and thrust bearings, 
one being illustrated in Fig. 244. This is constructed to take either 
form of load equally well, and for this reason has displaced a pair of 
ball bearings in many circumstances where formerly it was thought 
necessary to use a radial ball bearing to sustain the load and a thrust 
ball bearing to absorb the end thrust. In this way it represents an 
important economy. Furthermore, it is economical of space, as it 
takes less room than the former pair of bearings used for the same 
two purposes. 


Importance of Flywheel. With the growing tendency toward 
smoother and more even running and the demand for lower low 
speeds and higher high speeds, the flywheel, which was looked upon 
as a necessary evil for many years, is now receiving more attention. 
The designers realize that the flywheel plays an important part in 
balancing — that if it is too heavy the engine will be slow to pick up 
speed and will not run very fast, and that if it is too light, the engine 
will be very "touchy" and will not withstand quick variations from 
high to low or low to high speed, nor will it throttle down very slowly. 

Flywheel Characteristics. WeigJits, With weights being reduced 
to the limit in order to get higher engine speeds, the flywheel has 
received some paring down. Formerly, designers erred if at all 
on the heavy side with flywheels, but when they began changing the 
entire design of the engine to save a few pounds, they did not overlook 
the flywheel. In the flywheel, too, the growing use of counterweights 
has had an influence. / 

Sizes. Designers realize, now that the hampering sub-frames are 
out of the way, that the larger the diameter the better the flywheel 
effect for equal or less weight. As a result, many flywheels have been 
increased in diameter as they have been reduced in weight. 

Shapes. Flywheel shapes, that is, sections, used to be rec- 
tangular or almost square, with a solid web or spokes practically in 
the center. Clutches, starter-ring gears on the outer surface, and 
other contributing causes have changed the character of flywheels 
so that few have the rectangular shape or character now. The method 



i)f using fan blades as flj-wheel spokes has also fallen into disuse; 
although at one time it was widely tried and appeared to be a means 
of eliminating the fan entirely. 

Something of the present shape of fij'wheels can be seen by refer- 
ring back to Figs. 217, 222, and 22.S. In the first figure, the flj-wheel 
has a triangular section with a solid web set at an angle so as to bring 
the flywheel nearer the engine; the inner surface is tajXTed to suit 
the clutch , In Fig. 222, the shape is entirely different and apparently 
much lighter. Tlii.s is an eight-cylinder engine. Here the flywheel 


Methods of Fastening Flywheels. That part of the fl>^heel 
which is most interesting to the repair man is the method of fastening, 
or rather the inverse of this, the method of removal. There are three 
general methods of fastening flywheels to crankshafts, and these are 
shown in Fig. 245. They are the plain round end with a key, as 
shown at A; the tapered end with key, nut, and lock nut, as shown at 
B; and the method of bolting to a circular flange integral with the 
crankshaft, as indicated at C. The first is widely used for stationary 
gas and marine engines of very low price, but very little, if at all, on 
automobile engines. The second has been used, but is rapidly going 
out, as it is, like the first, a low-priced method which did not prove 
satisfactory. The third method is rapidly becoming universal. 

In use, the flywheel flange on the crankshaft is generally five 
• or six inches or a figure between these, in diameter, with six to ten 
bolts. In the form shown at C, Fig. 245, the flange is exterior to the 
fly-wheel, but in Figs. 217 and 223, the more general method of grooving 
the fl^-wheel hub to receive the flange will be noted. In Fig. 245, 
the bolt shown has a countersunk head let into the flywheel surface; 
in general, the bolt head is either standard or else round and set into ar 
countersink. In this case, it is slotted for a screwdriver. Also a 
single nut is shown, whereas a nut and lock nut, or, at least, nut and 
lock washer, are always used. 

Flywheel Markings. As has been noted previously under 
Valves and Valve Timing, the surface or rim of the flywheel generally 
carries upon it marks to indicate to the repair man the timing of the 
motor. Some makers give only one or two marks for a single cylinder, 
reasoning, with some degree of correctness, that if the first cylinder 
is set right, the others must be pretty nearly so, and that more marks 
would only confuse. Others put on their flywheel all the marks for 
all the cylinders. 

Summary of Engine-Qroup Treatment. In Parts I, II, and III, 
the entire engine group has been discussed in detail. The different 
sections have been handled according to present practice and methods 
of operation. It is easily possible that the near future may bring 
about the elimination of one or more of these groups or its combina- 
tion with some other. 

The engine, too, has been discussed in its present form only, 
although some attempts have been made here and there to rndxeaXi^ 


the trend of developments. He would be a very foolish man who, 
knowing the past history of the automobile engine, would say that it 
has now reached perfection and will alwaj'3 have its present form. 
On the contrary, there seems every reason to believe that hardly a 
single feature of our present-day engine, at least in its present form, 
will be found in the up-to-date engine of ten or twenty years from 
now. This constant change renders a work of this kind aItno?t 
impossil)!^ of absolute up-to-dateness, for changes are actually made 
and put into use while the book is being printed. As far as possible, 
however, the work aims to discuss the modern developments and yet 
to give the repair man, in particular, the information he needs as he 
conies in contact with cars of all classes, ages, and conditions. 

Q. For what purposes are valves used? 

A. \'aivfs art' used (1) to admit the niLvtiu* created in the 
{■arbnretiir into the cylinders at the proper time in the stroke and in 
till' j>rn|>frqii!iiitity (called admission or iidet valves); and (2) to allovr 


A. Because the operation of opening and closing the valvea 
comes on every other stroke- only, and the camshaft really works 
twice as slowly as the crankshaft. 

Q. What is the general form of a valve? 

A. The usual form is called a poppet valve, and its section is 
that of a letter T, having a long slender stem at the top of which is a 
large flat head. The lower surface of this head is machined off to 
fit the seat in the cylinder, while the upper surface is rounded up to 
the center, where a slot for a screwdriver is provided. 

Q. Are there other forms of valves? 

A. The piston form of valve is little used, but the sliding-sleeve 
valve is used on all Knight t^pe of engines and some others. In addi- 
tion, a few motors have been built with rotating-disc valves. The 
piston valve is similar to the usual piston, having a reciprocating 
motion in a special round-valve chamber made for this purpose. In its 
movements up and down, it uncovers ports in the walls, thus giving 
the equivalent of the poppet-valve opening. The sliding sleeve is a 
hollow cylindrical member entirely surrounding the piston and recip- 
rocating in the same manner. In its up-and-down motions, ports in it 
register with ports in the cylinder walls at the proper points in the 
cycle, thus corresponding to the opening of the poppet valve. The 
rotating-disc valve acts on the same plan but consists of a flat or 
a conical disc which is gear-driven from the crankshaft. It has a hole, 
or port, in it which registers with other ports in the cylinder at the 
correct time in the cycle. There are other forms of valve but none 
in wide use. 

Q. What are the advantages of the poppet valve? 

A. Its simplicity is its greatest asset. The poppet valve is 
the simplest and most easily understood form of all. In addition, it 
will withstand continuous operation at the highest temperatures. 

Q. What are its disadvantages? 

A, It affords a comparatively small opening, smallest at the 
beginning and ending of the suction stroke, where it should be largest; 
it has a noisy hammering action which makes for rapid wear, constant 
adjustment, and frequent renewal; the actual seat is so small and is 
exposed to such variations of temperature and other severe conditions 
that it tends to wear out and leak very rapidly, thus reducing the 
power and speed, rendering action uncertain and calling for fret^uent 


regrinding; finally, the necessity for ready accessibility for adjusbaent 
allows the driver, or operator, to alter the action with 8 consequ^it 
influence upon the output. 

Q. Can any of the disadvantaKes be overcome? 

A. The opening cannot be changed, but the noise can be teduced 
by enclosing the whole valve action in removable covers. The influ- 
ence of hammering in the way of wear, need for adjustment, renewal, 
leakage, etc., can be minimized by the use of tungsten ateel, which is 
harder and wears much more slowly. The use of this material also 
lessens power and speed losses, uncertain actiqn, and frequen<y of 

Q. Is there any way in which the design can hifluence these? 

A. Itecent tendencies and experiments have shown that with an 
arrangement for positive, or mechanical, closing of the valve, springs 
can be made very small and weak, thus eliminating the cutting 
action of the usual stiff spring on the cams and reducing the ham- 
mering action and the noise. 

Q. Have sleeve valves any springs? 

A. No. They are operated by eccentrics from the eccentrie 
shaft, which corresponds to the camshaft in a poppet-valve syston. 


ien as long as possible, this sometimes overlapping the inlet opening 
id always passing the upper dead center. 

Q. What is the average valve timing? 

A. The timing of fifty-six American motors, including perhaps 
le hundred different models, averaged as follows: inlet opened from 
>per dead center to 21® beyond — average 10® 48'; inlet closed from 
® to 46® 22' beyond lower dead center — average 35® 7'; exhaust 
»ened from 31® to 57® 30' ahead of lower dead center — average 50® 10'; 
haust closed from upper dead center to 21® beyond — average 9® 20'. 

Q. How does the repair man know what the correct timing is? 

A. Practically all makers give it in their instruction books and 
her literature as well as marking it upon the fl^^'heel surface. 



Q. How are the cams usually made? 

A. On all the better motors, the cams are formed integral with 
e camshaft, which is machined, hardened, and ground as a unit, 
li^ keeps the timing always the same, which is sometimes not the 
se when cams are made separate and keyed and pinned in place, 
oreover, the integral cams are more accurate, because the machines 
lich have been developed for this purpose insure absolute accuracy. 

Valve Guides 

Q. What is the valve guide? 

A. That member which forms the bearing as well as the support 
r the valve stem. Its importance can be judged from the fact that 
e guide holds the valve in line with its seat so that it seats itself 

Q. How are valve guides usually made? 

A. Generally, they are of cast iron and removable, being 
rewed into the cylinder from below. The diameter is made as small 
possible and still give sufficient stiffness and strength; the length is 
ide as great as possible, for the entire length of the valve guide 
bearing surface for the valve stem. 

Exhaust Manifold 

Q. What is the influence of the exhaust manifold? 

A. To remove the exhaust gases from all cylinders as quickly 
d as thoroughly as possible. If this is not done, the burned gases 


will retard the next outflow of gas, until finally the engine may be 
stopped because it is not receiving rich enough fuel. The best fonn 
of exhaust manifold is the one which does this work most quickly and 
most thoroughly. 

Q. What is its genera) form? 

A. \ long cHst-iron member of round or rectangular section, 
slightly hirger at iIk' millet end, and bolted to the cylinder casting. 

Q. How can this be improved? 

A. Recent experiments have shown that an arrangement of 
shape and size can be effected which will bring about an ejector effect 
immediately back of each exhaust orifice. This will produce a 
slight su<'tion upon each succeeding \olume of burned gas, which will 
increase the efficiency' of the exhaust and thereby improve the power 
of its motor. 

Q. ' What is the purpose of the muffler? 

A. Til rfdiK'c the pressure of the exhaust gases so that when 
enLtTf;iiig into the .Ltiiiusjihcre they will do this without noise. As 
tlicy eiruTp' fnniL the cylinders, the pressure is fairly high, and if they 


Q. What Is the general cooling method? 

A. There are two methods in general use, called the natural, 
or thermosiphon, and the pump systems. The former is so-called 
because^the natm^l increase in temperature of the water is used to 
circulate it to the radiator and back. The latter is called a pump 
system, because a pump is used to force the water around. 

Q. Are there other differences between the two? 

A. In the thermosiphon system, the difference in pressure oea- 
ted by the increasing temperature is so slight that all bends must 
be made very easy and all pipes made very large, so the water will 
pass easily. Also the system as a whole must be short and compact 
with radiator close to motor, and with little difference in level between 
the highest and lowest points. The added weight of larger pipes and 
their appearance just about balance the simplicity and smaller number 
of parts. 

Q. What general types of radiators are in use? 

A, The cellular (which may have square, round, or hexagonal 
cells) and the tubular form with horizontal fins sweated on are the 
two forms generally used. 

Q. How does the water circulate in these two forms? 

A. In the cellular form the water is in very thin sheets between 
the cells, with a consequently high ratio of air space to water space. 
The water is forced to follow a zigzag path to add to the cooling effect. 
In the tubular form, the water flows from an upper to a lower tank ' 
through the vertical tubes, which are of relatively larger diameter as 
compared with the water space in the cellular form — | against ^. 

Q. What is the usual form of pump? 

A. Four forms of pumps are used for water circulation: the 
centrifugal, the gear, the plunger, and the vane. The first two are 
used about equally on the majority of American pleasure cars, the 
last two having but a few adherents. 

Q. What is the latest move to improve water circulation? 

A, The use of a thermostat to control the flow of the water 
according to its temperature. This device holds the water in the 
c^'linders until a certain predetermined temperature is reached, when 
it opens and allows the water to flow through the radiator and be 
cooled. By setting this so that this predetermined temperature is 
fai^, but not so high as to be dangerously close to the boiling point. 


the efficiency of the engine is increased, for a hot engine works better 
than a cold one and gives more power. 

Q. What is the purpose of the fan? 

A. To increase the efficiency of the radiator by drawing more 
air through it and thus cooling the water more. 

Q. How is the fan generally driven? 

A. The belt drive, using a flat or V-type belt is general because 
of its simplicity, but a few better cars have gear or chain drive; 
the latter method has increased in recent years particularly with the 
V-type motors, for in those it has been found easy to drive the fan from 
a shaft in the immediate vicinity. 
Questions for Home Study 

1 . Describe in detail the timing of the Knight motor. 

2. Tell how to regulate and check up the valve action from the 
flywheel marking. 

3. How are silent-chain camshaft drives adjusted? How are 

4. How is the valve-stem clearance adjusted? 


Q. What is meant when lubrication is referred to? 

A. In general, the lubrication of the engine, because that is so 
much more important than the lubrication of any other part or group 
of parts. If the engine is run without lubricant, even for a very short 
time, it is ruined. On the other hand, many of the car parts can be 
run without lubricant for days and days, yet no damage will result. 

Q. What are the most used systems for the internal oiling of 
the engine? 

A. The most used systems are,: the splash, the pressure, and a 
combination of the two, known as the splash-pressure, or constant- 
level, system. The first is simple, oil being provided in troughs into 
which the connecting rods dip, thus spreading the oil all over the 
interior of the motor and lubricating ever\i:hing. The pressure sys- 
tem forces oil under pressure to all the important bearings and surfaces 
by means of interior-drilled oil leads or special pipes. It requires a 
pump, driven from some engine shaft, one or more strainers (for the 
oil is used over and over), the special drilling or piping, a gage on the 
dasb to tell the driver how the system v& "v? oxVk^^^ «xA \si ^«gbm6 oBses 


an adjustable pressure valve. The splash-pressure form has the oil 
leads to the important points only. Then the excess runs down into 
the crankcase and fills troughs into which the connecting rods dip. ' 
In some cases, these troughs are filled by direct individual leads off 
of the main oil pipe. Then when the rods dip into the oil, all benefits 
of the splash system are obtained. The fact that the pump main- 
tains a constant level of oil in the troughs has led to calling this the 
constant-level system. 

Q. What pressure is used in the pressure system? 

A. Prior to the introduction of V-t^T^e and high-speed motors, 
a few pounds less than 5 was considered sufficient. Now, many 
motors have a system which works under 40, 50, 60, and even 70 
pounds pressure. The oil leads are smaller, but the amount of lubri- 
cant which the bearing receives is much greater than previously. 

Q. What is the external lubrication of the motor? 

A. The lubrication of the accessories, such as magneto, water 
pump, starting motor, generator, air pump, fan, etc. Practically 
all these have oil holes, oil cups, or grease cups. The last named must 
have a special heavy grease or pure mutton or beef tallow, as a thick 
lubricant is needed to resist the passage of the water and not wash 
away. Otherwise the external lubrication is fairly simple and requires 
little attention. 

Q. What are the most used types of oil pumps? 

A. Like the water pump, all forms are used but the most popu- 
lar are the cam-operated plimger, the gear, and the plunger. 

Q. How are these driven? 

A. By gear from any convenient shaft, as camshaft, crankshaft, 
water-pump shaft, magneto shaft, etc. When the pump is enclosed 
in the crankcase, it is almost invariably driven from one of the 


Q. How are other parts of the car lubricated? 

A. Aside from clutch, transmission, rear axle, and wheels, prac- 

tically all parts are lubricated by means of grease or oil cups or ^oil 

holes* The latter are rapidly being eliminated for the sake of clean- 


Q^ What are possible future developments in oiling? 

A At present, there are two tendencies noticeable, one being 

jct/^nslon of fprced lubrication to many parts outside the engine. 


In the case of the Fergus car, tlie springs are enclosed in leather ImxiIs 
and lubricant supplied from the engine oil purnp. Siinilariy, clutch 
and transmission are oiled from the engine pressure system. The 
I9I7 Marmon car is claimed to have but four or five lubricant points 
outside of the engine system. Another maker has adopted the 
leather-enclosed and lubricated springs. All these signs point toward 
less lubrication for the dri\'er and owner to do, more points being 
included in the engine system. The other noticeable point mentioned 
has been partially covered; it is the reduction in number of points 
requiring individnal attention, by other means than extending the 
engine pressure syiiteni to them. 

Q. How should graphite be used? 

A. Graphite shuuld be used very sparingly, for a little of it goes 
a long way. It is not like grease which is used up very quickly, but 
ia more or less indestructible. 'When a combination of graphite and 
grease is use«l, it will lie found to last twice as long at any given point 
as the same quality of grease alone. Graphite in its very finest form, 
when introduced into the engine system, is beneficial as it seems to 
put a kind of polish, or surface finish, on the cylinders, which resists 
wear. After tliis liiis been put on, less lubricant, by at least 20 per 


2. How is the Cadillac eight motor oiled? Give details. 

3. What is the usual method of changing the amount of oil 
pumf>edy in a pressure system? 

4. Select some method of driving the oil pump, which seems 
simple to you, and describe it, telling why you selected it. 

5. How would you lubricate spring leaves, with what and how 
often? fan bearings? front wheel bearings? magneto shaft? 

6. How do you select a good engine oil? 


Q. How does a light flywheel affect an engine? 

A. The engine will be easy enough to start and stop, but very 
touchy on changing speeds — too quick a change will kill it. More- 
over, it will not run very slowly. 

Q. How do present flywheel sizes compare with those of former 

A. Present fl^'wheels are larger in diameter but narrower and 
lighter in weight. The increase of diameter made by the elimination 
of subframes allowed cutting down the width and weight because the 
flj'wKeel effect is equal to its mass times its radius, so that by increas- 
ing the radius the mass can Ik» reduced. 

Q. What are the usual methods of flywheel fastening? 

A. The flange forged on the crankshaft and through bolts is 
almost universal. A few niotors are still made with a round crank- 
shaft end and a large key; or with a tapered shaft end, and a key, a 
nut, and a lock nut. The latter form is used when the crankcase is of 
the barrel type with removable end plates and is so made as to allow 
removal of the crankcase end plate at the rear. In some few cases 
the flv^wheel is made this way so as to allow putting on or taking off 
a ball bearing at the rear end of the crankshaft. 

Q. What are the mitrkings on the flywheel rim? 

A. The timing is now generally marked on the surface of the 
flwheel to guide the owner or repair man in making adjustments or 
in assembling the engine correctly. The adjustments vary; some 
makers give the complete timing for a singk* cylinder, others give a 
few points for all, and still others give all the points for all the cylin- 
ders. The latter is the l)est way. 





Classification. Principal' among the indispensable parts inter- 
filing betweerTengine and road wheels, and one which may be a 
urce of great joy or correspondingly great wrath, according to 
bether it be well or poorly designed and fitted, is the clutch. There 
e six forms into which clutches may be divided, although not all 
them are in general use in the automobile. Only the first four are 
idely used on automobiles. These different forms are: 

(1) Cone clutches 

(2) Contracting-band, or drum, clutches 

(3) Expanding-band, ring, clutches 

(4) Disc and friction clutches 

(5) Hydraulic, or fluid, clutches 

(6) Magnetic, or electric, clutches 

The necessity for a clutch lies in the fact that the best results 
•e obtained in an automobile engine when run at constant speed. 

1 as much as the speed of the oar cannot, from the nature of its use, 

2 constant, it requires some form of speed variator. This is the 
3ual gear box, or transmission, but? in addition, there is the necessity 
f disconnecting it from the motor upon . starting, since the engine 
mnot start under a load. There is also the necessity for disconnect- 
ig the two when it is desired to change from one speed to another 
ther by way of an increase or a decrease. So, also, when one wishes 
> stop the car, there must be some form of disconnection. There 
re, then, three real and weighty reasons for having a clutch. 

Requirements Applying to All Clutches. In a serviceable clutch 
lere are two general requirements which are applicable to all forms, 
hese are gradual engagement and large contact surfaces, although 
le latter requirement may be made to lose much of its force by 


making the surfaces very efficient. In the cone dutch, gradual 
engaging qualities are secured by placing a series of flat springs under 
the leather or clutch lining. By means of these springs, acting against 
the main clutch spring, the clutch does not grab, since the large 
spring must have time in which to overcome the numerous small 
springs. In this way, the engagement is gradual and the progress of 
the car is easy as well as 
continuous. I 

The specific neces- 
sity in a cone olutdl, 
whether it be direct or 
inverted, is atwofoldo 
— sufficient friction sur- 
face and proper angu- 
larity. The latter, in a 
waj", affects the former, 
as will be discussed more 
in detail later. The an- 
gularity varies in practice 
from S to 18 degrees. 



end to engage it. This is called the inverted, or sometimes the 
reversed, cone clutch. 

A great disadvantage of the inverted form is that the spring must 
be carried between the two cones, which means that it is inside where 
it cannot be reached for adjustment. This form causes trouble in 
assembling because the male cone must be put in place with the 
spring between it and the fl;T\'heel before the female can be set into 
its place and bolted up. These two big sources of trouble have caused- 
designers to turn to the direct tjpe more freely, as it lends itself 
readily to an external 
adjustment. If the spring 
is outside, it is easily put 
into place and as easily 
taken out. 

An e-xcellent exam- 
ple of the direct cone 
clutch is seen in Fig. 240, 
which shows the Stude- 
baker clutch in section. 
The noticeable point 
about this clutch is its 
simplicity. It, will be 
noted that the spring is 
entirely enclosed, so that 
when it needs adjusting 
the repair man must 
open the universal jomt 
and operate the bolt A which regulates tlie tension of the spring. 

Another good example of the simplicity of the cone clutch is seen 
in Fig. 247, which is an aluminum member with bosses cast for cork 
inserts. Between the inserts may be seen the fiat heads of the copper 
rivets which hold the clutch facing in place. Obviously, this has the 
same disadvantage of internal, and thus inaccessible, spring. 

In the cone type of clutch, shown in Fig. 248, the inaccessible 
spring is avoided. In addition, a number of small springs are used in 
place of one very large and very stiff one. The ease of adjustment 
and the greater ease in handling the springs make this clutch a much 
better design for average use from the repair man's point of view. 



An example of the inverted-cone type is shown in Fig. 249, whidi 
shows the clutch on the four-cylinder Steams- Knight, This tj-pe hu 
an o<id number of small springs equalI^'' spaced around the clutbh, 
but these cannot be adjusted from the outside. 

Contracling-Band Clutch. A short consideration of the band 
at> le (if clutch shows that this does not differ radically from the an& 
nat>~ band brake, either in construction, application, or actual work' 
_^ I ing. The difference in the 

*'-jMa) two lies in the fact that the 

'^■, i^3l/ band, as a clutch, b dfr 

. -y. — P^s signed to transmit pi>wer 

y>^ — '■'I .fc;^^yy^ with as little loss as possi- 

ble, while the band as ft 
brake is designed to absorb 
the forward energy of ft! 
raovTng vehicle In the short- 


of the clutching lever, while the other end of the band is fastened to 
the middle of this lever. The clutching pull comes upon the upper 
extremity of the lever. Then the band acts to aid in clutching itself, 
i.e., a scissors action is obtained, and the required pull is lessened. 

This construction can be seen quite plainly in Fig. 287, which 
shows the planetary transmission anti bands used nn Ford cars. In 
this, the low- and reverse-speed 
bands are shown in full. This 
is of particular interest as Mr. 
Ford is now the only American 
maker using the planetary form 
of transmission, all other makers, 
even of very low-priced machines 
— some below the Ford price — 
having gone to . the selective 
sliding-^ar form. 

Expandtng-Band, or Ring, 
Clutch. The expand ing-band 
clutch finds favor among few. 
Like the contracting band, which 
is very similar to the band form 
of brake, the expanding band is 
much like the expanding tj-pe of 
brake, except that the clutch is 
used to form the connection be- 
tween two rotating parts. Viewed 
from the standpoint of pure 
engineering, the expanding band 
is little different from the cone 
type of clutch, granting that the 
angularity of the operating cam 
is the same as that of the cone. 

Much depends upon how the band is expanded. This expansion 
is usually accomplished by means of screws, which may be either 
right-handed or left-handed or both. 

Another form is expanded by a double-threaded screw operated 
by a lever. The lever, in turn, is moved by a pair of sliding collars on 
the miun-clutch shaft, the clutch foot pedal moving theae fow«.T4. 

FiC 249 lDv<rt«d Cone Ctutob Uied an 

SteHriW'KiUBht Four-Cylinder Can 

CmrUtii of F. B. Sttarnt Company, 

CttrOand, Okio 


Disc Clutch. With its iidvent in 1904, the muItiple-diRC dutch 
has steadily grown in popularity, until t^xla.v it is looked upon us the 
most satisfactory- solution of the diffirult clutch problem. Designers 
who have once adopted it, seldom, if ever, go l)at'k to aiiotlier form, 
while of the new cars coming out from time to time nearly three- 
fourths are equipped with some form of disc clutch. 

Popularity Compared with Other Fonm. Statistics for I9K 
showed that the disc form of clutch was easily the most ixipular type. 
Of 2.10 different chassis for 1914, I19wereequipped with disc clutches, 
97 with the cone, 9 with a contracting-hand tj-pc, and but 5 witli an 
expand ing-band f()mi. The relative figures for \9H> were about 94 



as can the outside spring of the disc. An interesting point in this 
connection is that the transmissions also are interchangeable, although 
the type, Fig. 252, with roller bearings is intended for a moderately 
heavy passenger car, while that in Fig. 251 is foj lighter work. 

Simple Types. The simple tj-pes differ in number and shape of 
discs, method of clutching, material, and lubrication; but in principle 
all are alike. This clutch is one in which the flat surfaces properly 
pressed together will transmit more power with less trouble than any 

other form. By multiplying the number of surfaces and making 
them infinitely thin, the power transmitted may be increased indefi- 
nitely. That this is not idle fancy is shown by a number of very 
successful installations of 1000 horsepower and over in marine service. 
The minimum number of plates in use is said to be three, but 
very often the construction of a three-plate clutch is such that one or 
two surfaces of other parts are utilized, making it a two- or even one- 
plate clutch in reality. In the Warner clutch, shown in Fig. 252, 
there are really but two clutching surfaces, the face of the inner plate 


against the flyn'heel and the outer face agunst the engapng dbc. 
Both plates are faced with suitable friction surface but it really is a 
one-disc clutch. 

Multiple-Disc Clutches. Tie modem tendency in disc clutches, 
however, is away from those of few plates requiring a very hi^ 
spring pressure — since the -friction area is , necessarily limited— 
toward the multiple-disc variety, in which a very large area b 
obtained. The large area needs a very light spring pressure, and 


In the true multiple-plate clutch, there are three general varieties 
met with in practice: the metal-to-metal with straight faces; the 
metal-to-metal with angular or other shaped faces designed to 
increase the holding power; and the straight-face kind in which metal 
does not contact with metal, one member either being lined with a 
removable lining or fitted with cork inserts. 

Melal-to-Metal Dry-Disc Type. The metal-to-metal method has 
the additional advantage of having the central part within which the 
clutch is housed very small in diameter, so that the portion of the fly- 
wheel between the rim and the clutch housing may be made in the 

form of fan spokes that convert it into a fan which serves to cool the 
motor better. 

As the various examples of disc clutch shown would indicate, 
the designer has had his choice between a few large discs and a lai^ 
number of small ones. If he chose the former, the clutch could be 
housed within the flj-wheel, but that would make it inaccessible. If he 
chose the latter, the clutch could not be kept within the flywheel 
length. A separate clutch housing would be a necessity, but the 
clutch could be made accessible and flywheel fan blades could be used. 

Another example of the plain metal-to-metal disc clutch is shown 
in Fig. 253. In this case also the clutch is not housed in the flywheel, 


as in most of the preceding examples of this fonn of chitch, but in the 
forward end of the tninsiiiission case, that is, instead of motor and 
clutch forming a unit, the clutch is a unit with the transmission. I( t» 
claimed that this position makes it more accessible, since it brings tbs 
clutch directly under the floor boards of the <!river's compartment 
where it can be lubricated iietter. The lubrication is etfected tlirougb 
communication with the gear part of the case, which is always filled 
with lubricant. 

In the figure it will be noted that there are 13 driven discs, with 
keyways, which hold them to the driven drum. Note that the dnim 
is held to its shaft by means of a pair of large set screws. The clutch- 
ing springs are of small diameter and size, space*! etpially around the 
periphery of tlie discs ; each disc is enclosed in a small and thin met*! 
casing. Attention is called also to the universal joint shown. This 
joint forms the rear end of the driving connection with th« flywhed, 
which will be refcrrefl to later. These discs are flat-stamped out of 
sheet steel with tlie proper ke>-wa,va for internal or external holdings. 

Use uf Faringn. The more modem di.-M" clutch has two sets 
of sheet metal discs, one of which is faced on one or both sides wiUi 
a special material. Without a single exception, all the diac ctutcbn 
ahnun hnvP hu-l nlnir. cli«^ n™in=t r.!«in /li«/-i ThU mnW™ » ^imijt. 



To present an example of the faced t^-pe, Fig. 254 shoe's the 
multiple-disc clutch of the eight-cylinder V-tjT* Cadillac. In this 
illustration the eight driving discs can be seen with the facing on 
each side of each one. This facing is of wire-mesh asbestos, anrl 
between each pair of discs comes a plain driven disc, so that it has a 
facing of the asbestos against each side of the metal which it grips. 
The keys which hold and drive the Inner discs can be seen on the 

end of the housing, while the slots into which the keys project can 
be seen on the discs. By examining the group closely, the driven 
plain discs can be seen between each pair of the drivers. The 
method of driving these discs through a multiplicity of keys and 
grooves is unusual, but it is a good example of Cadillac thoroughness. 
Fig. 2.S4 also shows the pedals and the exterior of the clutch case 
where it bolts up to the engine. This indicates how a unit power 
plant simplifies the control group and eliminates parts. ' 



Floaiing Discs a Novelty. The cIutcK on Locomobile ears, 
shown in section in Fig. 255, is very much like the Cadillac just 
shown, except for the novel featm-e that the fabric facings are not 
attached either to the driving or to the driven discs but float between 
them. This fabric, u.-iually a woven asbestos material with a central 
core of interwoven metal wires, instead of being attached to both 
sides of every other disc or to one side of every disc, is not attache! 
at all. The rings for the fabric discs are made up in the form of 
annular rinfirs. They have the same inner diameter as the inside of the 


The discs of this unusual clutch had a perfectly flat outer portion 
and B conical inner portion, only the latter taking part in the trans- 
mission of power. In this disc form, then, we have' the advantage 
of the disc economy of space, together with the advantages of the 
cone clutch and the additive gain of running in a bath of oil. 

Another form utilizing this principle, and one that is more widely 
used, is that known as the "Hele-Shaw" so named from its inventor, 
the famous English scientist, Dr. H. S. Hele-Shaw. This ia essen- 
tially a flat disc, as shown at A, Fig. 256, with a ridge B at about 
the middle of the friction surface; this ridge consists of a portion 

Hele-Shaw Diec Clutch. Showing Cone Surlu 

of the surface, which has been obtruded during the stamping process 
in such a way as to leave the surface of the ridge in the form of an 
angle of small height. The angle used Is 35 degrees, and this value has 
been determined upon experimentally as the best. Fig. 256 shows a 
cross-section through au assembled clutch, which reveals the clutch 
angle very plainly. In use, the ridges nest one on top of the other; 
and in the extreme act of clutching, not only the flat surfaces but 
both sides of the ridge are in contact with the next plate. Thus, not 
only is the surface for a given diameter increased, but the w^'^ 
shape is also taken advantage of. 


UijdmnUc Clutchen. All the methoiia of engaging an<i dis- 
engaging the engine at will, aa discussed before, have been of » 
mechanical nature. The hydraulic clutch, on the otlier hand, par- 
tjikes more of the fluid nature, although it is operatwl by mechanical 
means. Ordinarily, it is in the nature of a pump with a by-pass, 
the pump working at ordinary speeds to force the heavy liquid, 
usually glycerine, through the hy-pas-i. To clutch up tightl>', how- 
ever, the by-pass is closed and. the liquid being unable to circulate 
while the pump continues to operate, the whole device is rotated as 
a unit. In this case it operates just as tiny other clutch, but, due to 
the sluggish action of the fluid, it is slower to respond. Then, t<». 
the grave question of leakage is always present, and the smallest Imk 
puts the clutch entirely out of use. These disadvantages, together 
with the necessary complications, have retarded the development (tf 
the hydraulic form so that there are few of that type in use t<xiay. 

Magnetic Clutch. .-MI the foregoing clutches pn^sont in one 
form ()r another \er\' complicated devices for freeing the transmission 
shaft from the engiiie shaft, but the magnetic clutch is a device* which 
has simplicity for its foremost argument. The magnetic clutch 


Accumulator Company, Chicago, a centrifugal electric-generating 
clutch. This name gives a little clue to its action, which is that of a 
combination of the usual friction clutch and- that of the electric- 
magnetic drag between armature and fields of any electric machine. 
In addition to its clutching feature, its ability to drive when 
partially clutched makes it, in effect, a transmission, so that it is 
designed to replace the usual clutch, gearset, flywheel, electric gen- 
erator, and starting motor, it is composed of two parts: an arma- 
ture, which becomes the fiv-wheel; and a field mounted on the pro- 
peller shaft. The former carries an internal commutator, and the 

lattercarriesbrushholderswhichholdbrushesagainst the commutator. 
These brushes are mounted so that the centrifugal force of rotation 
increases the force with which they press against'the commutator. 
Thus there is a variation from practically no contact up to the maxi- 
mum, at which point the centrifugal force is so great that field and 
armature revolve as a solid unit. 

This construction is well indicated in the two illustrations of this 
device, Figs. 257 and 258. Fig, 257 shows the field unit mounted on 
the propeller shaft in which F is one of six field poles, B ?. bTMsiv,%.Tv^ 
C one of the collector rings. Fig. 258 is an external v\e« -^iVwii ■^ty«* 


the clutch assembled. In this illustration the brushes B are shown 
pressed out against the commutator by the centrifugal force. 

An automobile built in France — the Ampere — uses the electric- 
generating clutch construction excluaivelj', the master clutch being 
dispensed with in favor of an individual-clutch transmission. The 
differential is dispensed with, and in its place a pair of magnetic 
clutches — une fur each wheel — are used. The difl'erential action is 



yhich compresses the clutch spring or springs and allows the clutch 
nembers to separate. This throws the clutch out. To throw it 
>ack in, remove the foot pressure from the pedal, and the springs 
igain exert pressure and force the parts together. This action 
»uses them to take hold. Tliere was a time when a considerable 
lumber of cars had the clutch so constructed that the pedal held it 
n and the springs threw it out, just the reverse of the present plan, 
rhis method is no longer used, as it necessitated a constant pressure 
)n the pedal while driving — a very fatiguing process. 

Gradual Clutch Release. The Dorris clutch, made by the Dorris 
Motor Car Company, St. Louis, Missouri, Fig. 259, is a new arrange- 
ment of the clutch pedal, 
and its operation is such 
that the clutch is -released 
or thrown out with very 
light pressure on the 
pedal. Pressure on the 
petlal A is transmitted 
by the shorter lever arm 
B, thus greatly increas- 
ing the leverage. This 

pressure is transmitted to 

lever C and through it to 

lever D, these two being 

hung on the frame cross 

member £. As C is much 

longer than D, there is 

another multiplying ac- 
I tioQ here. This does not 
! net directly upon the 
: clutch but upon the upper 

end of the clutch shifter 

'', which is attached to the clutch at G and pivoted at its lower 

end // — here again in a multiplying action. The net result of these 

three multiplications is a combination which will release the -strongest 

and stiffest clutch with a very alight pressure of the foot. 

Clutch Pedals. It has been the general practice in the past t^a 

have the clutch pedals separate and distinct, wVtK t.\ve aeT\\!ce-\««Js.^ 

Fi(. 2W, MulCiplyins l^vpr oF Dorria Clutcl 
Make PhUI Preraure Light 
Canrlnu «/ Dorrit Motor Car Cimpanv, SI. 


pedal on a concentric shaft occasiouaJIy. Now, h<iwever, tiw rapidly 
growing practice of stmpliiioatioit and elimination, combined with the 
wide use of the unit imwer plant, is eliminating the so-called c\utth 
shaft with its hearings and fastenings to the frame, to the clutch 
operating yoke, and to many other parts. A« the Cadillac illiistm- 
tion, Fig. 254, shows and aa the Buick drawing. Fig. 2fiO, shows even 
better, all these shafts, rods, and fastenings can be eliminated and the 
pedals and levers mounted directly on or in the power unit. In the 
Buick illustration, the foot brake has a simple rod connection from 
the ear -1 on the |)edal to the brake-operating system, while the 


springs must he cared for. Generally, these two cases are cared for 
by a pair of grease cups, which are visible in Figs. 247 and 249. 
The operating rods are lubricated usually by means of small oil holes, 
either drilled directly into the part or covered with a small oil cup. 
In those cases in which the clutch runs in oil, it will be noted that a 
filling plug is provided, by means of which additional lubricant can 
be poured into the casing, Fig. 256. 

Clutch-bearing lubrication is highly important, particularly with 
clutches like the cone which must be kept free from lubricant and the 
drv disc in which lubricant is not used. Where the clutch itself 
runs in oil, it is a simple matter to lubricate the bearings, but in 
the other cases, oil or grease must be provided from one of three 
places: from a prolongation of the engine oiling system, as shown in 
Figs. 246 and 251; from the outside — generally by means of grease 
cups — as just discussed; or from the transmission end. The last 
form is used only in unit power plants; combinations of clutch and 
transmission, as shown in Fig. 253; and in cases. Fig. 256, where 
the construction allows a grease or an oil cup attachment at the 
transmission end, the transmission itself being some distance away. 

Clutch Bearings. The need for bearings in a clutch depends 
somewhat upon its nature and location, but regardless of these a 
thrust bearing is needed for the clutch spring. To explain this 
briefly, it is known that action and reaction are equal, and opposite 
in direction. For this reason, when a clutch spring presses the discs 
or parts together with a force of, say, 100 pounds, there is exerted 
in the opposite direction this same force of 100 pounds. In order to 
have something for this to work against, a bearing is used, and since 
it takes up this spring thrust, it is called a thrust bearing. Not all 
bearings are fitted to take thrust, as the majority are designed for 
radial loads only. For this reason a special design is needed. 

When the clutch is incorporated in the fl^^heel, two additional 
bearings — one for the end of the crankshaft and another for the 
transmission or driven shaft — are generally needed. The bearings 
will be noted in Figs. 246, 248, and 249, although the transmission- 
shaft bearing does not have the clutch combined with the engine but 
rather with the transmission. In the majority of cases, it will be 
found that a means of fastening the end of one shaft has been worked 
out so as to eliminate one bearing. This accounts for the lat^ 


number which show but two — tlie thrust and one other. In looking 
back over the clutches, it will be noticed also that nesriy all the bear- 
ings are of the plain ball fonn. Tlis is due in large part to the bet 
that the plain ball bearings take tqi the least room for the toad carried, 
both in diameter and width — a coattibuting reason being the fact 
that in many cases one of the shafts at parts can be formed to take 
the place of either the inner or outer ball race. 

dutch Adjustment. Adjusting a clutdi, as a rule, is not a 
difficult task as there are but two possible sources of adjustment — the 
throw or movement of the operating pedal or lever and the tmsion 
of the spring. ■ An adjustment is generally provided for each. When 
the fullest possible throw of the pedal does not disengage the dutch, 
an adjustment is required to give a greater throw. If the throw b 
correct, but the clutch takes hold too quickly and vig(»oualy, the 
spring pressure can be lessened somewhat to soften down this actlCH). 
On the other hand, when dropped in quickly, if it takes hcdd sk>iriy, 
more spring i)ressure is needed, and it should be ti^tened. 

Clutch Accessibility. Clutches are made accesuble in two ways: 
by their location on the car and by the relative ease with whidi they 
can be renio\e<l. Accessibility as to location is less in the various 



oil or grease on it. In that case it is desirable to roughen the surface. 
This may be done by taking the clutch out, cleaning the surface with 
kerosene and gasoline, and then roughing-up the surface with a file 
or other similar tool. 

In case it is not desired to take the clutch out, or when it is very 
inaccessible, the clutch surface may be roughened bv fastening the 
clutch pedal in its extreme out position nith some kmd of a stick 
cord, or wire, and then roughing the surface as far in as it can be 
reached, with the end of a small saw, preferably of the ke\ hole t\ pe 
as shown in Fig. 261. Before starting this repair it is nell to soak 
the leather with neat's-foot oil. This softens tlie leather and makes 



the roughening task lighter. 

Many drivers make the mis- 
take of driving with the foot 
constantly on the clutch pedal. 
This wears the leather surface 
and helps it to glaze quickly. 
The constant rubbing from fre- 
quent slipping makes the leather 
hard and dr>'. 

When a metal-to-metal oiled 
clutch slips, the trouble usually is 
[n the clutch spring, which is too 
weak to hold the plates together. To remedv shpping with this 
type, it is necessary to tighten up the clutch spnng adjustment 

Clutch troubles are not always so obvious In one instance 
the clutch slipped on a new car. In the shop the clutch spider 
seemed perfect and properly adjusted, also the spring but to make 
sure, a new clutch was put in. Still the clutch slipped To test it 
out still farther, the linkage was disconnected right at the clutch 
and then it held perfectly, showing that the trouble was m the link- 
age. On examination one bushing was found to be such a tight fit 
that it would not allow the pedal to move freely enough to release the 
clutch fully. When this was relieved a little, the clutch acted all right. 

R^lacing Clutch Leathers. Clutches offer many chances for 
trouble. The most frequent causes are the wear of leather facings 
with the attendant loss of power, and weak springs. Weak springs 
may be cured by screwing up on the adjusting nut or bolt pTo^vi>e\. 



Slippery leather may also be corrt'ctccl by washing; first with goM- 
line ami then with wuter, finally rou^huig the surface with a aiarse 
r»3p and replacing only after tlie leatlier is thorouglily eleaa. Dry 
leather is fixed by soaking in water or neatVfoot oil. !t should he 
replace<l while still moist, aad copious lubrication will keep it soft. 
The greatest problem in replacing a worn, charred, or otherwise 
defective leather lies in getting the right layout for the form of the 
new leather the first time. It must be remembered that the surface 

is a portion of ti 

and, therefore, its development is not eas>'. 
It is attacked iu this man- 
ner: Prepare the cone by 
removing the old leather 
\ and all rivets, cleaning out 

\ the rivet holes, and pmvid- 

\ ing new rivets. Measure the 

• rone, taking the diameters 

', at both the large and small 

t ends and also Uie width. 

■ '--._/■ Take a large sliect of papei 

.*' .' and lay otT upon it a figure 



IIIBCKJDAH may then be cut out and used as a pattern from 
which to cut out clutch leathers. If the distances AH and DJ be 
made approximately equal to or slightly more than ^Z>, the pattern 
will a little more than encircle the cone clutch. . 

After the leather has been cut out, it should be prepared by 
soaking in water or oil, according as its surface is fairly soft or rather 
harsh. In either case, it must be well soaked, so as to stretch easily. 
In putting it on the cone, one end is cut to a diagonal, laid down on 
the cone, and riveted in place. Next, the leather is drawn down 
tightly past the next pair of rivet holes, which are then driven into 
place. This is continued until the strip is secured. The leather is 
now wetted again, for, if allowed to dry off immediately, the shrinking 
action will break it out at most of the rivet holes and render it use- 
less. By drying it out gradually, a taut condi- 
tion may be arrived at without this danger. 

Handling Clutch Springs. Clutch springs, 
like the valve springs mentioned previously, 
are mean to handle and compress. The best 
way is to compress and hold them compressed ^^ -, ^ j 
until needed. For this purpose, a rig similar ^ -■* ' 
to that described for valve springs should be 
made but of stiffer stronger stock. A very 
good one can be made from two round plates, 
one small, and the other of larger diameter with 
a pair of L-shaped bolts through it. The 
spring is placed between the two, with the 
ends of the L's looped over the smaller plate, and then, by tight- 
ening the nuts on the bolts, the spring is gradually compressed. 

An excellent device for holding clutch springs consists of a 
simple pair of metal clamps which are juinefl together by three or 
more short metal bars, as Fig. 263 shows. If one particular clutch 
spring is handled continuously, the length can be made to fit this 
best, otherwise it will have to be made of any convenient length. 
The inside diameter of the clamps when fully open is greater than 
the outside diameter of the spring. The clamp is set in a vise or on 
a drill press and the spring set inside of it. Then the spring is com- 
pressed by working the vise handle or by lowering the drill-press 
spUtdie. When compressed down to the length used in the car, the 



ends of the clamp are tightened and the spring is lield by fricticm. 

Then tlie spring can be Imndled readily, using one of the metal bars 

es a handle. It is put into place, and then the retaining screws cbo 

be loosened and the clamp removed. 

Fierce Clutch. A fierce clutch is one that does not takv 

hold gradually but grabs the moment the clutcli pedal is released. 

In a metal-disc clutch, tliis is caused by mughenwl plate stirTaccH 

and insufficient lubricant, so that, instead of the plates twisdnf; 

gradually across each other as llie lubricant is sqiieexed nut from 

between them, they catch at once and tlie car atarta with it jerk. 

On a cone clutch, this fierceness is produced by too stronK n spring, 
too large a clutching sur- 
face in combination mitb a 
very strong spring, or a liaitl 
or [)urned clutch surface or 

Ford Clutch Troubles. 
There are now so many 
Fortis in use that the avcr^ 


cmter bolt, vfaich b ^ii^tly pvinnd and ptHrnbty hudeDed <,« 
the end, is screwed down io »5 to o^me into ixxitwrt with the end 
of the dutch shaft. After ti^tenin^ tbe center hoh. the T-hnMl 
bolts are righteoed until they pull tbe dnun off the shaft. 

Chitch Sp imi ag. A miuble which i$ both<n^iine but Dot 
dangerous is dutch spinning. This is the name applied to the 
action of the male dutch member when it c\>ntinue$ to nutate, or 
spin, after the dutcb 5|»in$ pre:5i>ure has been teleased. With tbe 
male member connected up to the principal transmission shaft ami 
gear, as is often the case, these members continue to rvute with it. 
This gives trouble mainly in gear shifting, for the member which b 
out of engagement is considereil to be at rest or rapidly appitvkching 
that condition. VNTien at rest, it is an easy matter to mesh anothn* 
gear nith this one: but when this one is rotating or spinning, it is 
not so easy, particularly for the novice. 



fif. m. Simplr Devin lor toHrtintt Corki ia ClutrbM 

Clutch spinning may l>e caused {U by a defect in the design. 
in which case little can be done with it; (2) by a defect in construi'- 
tion, as in balancing, for instance, which can l>e <i)n^H'ted; t)r (li) 
it may be due to external causes, as, for instance, in a bearing which 
has seized, owing to a lack of lubricant, etc. 

In an}' case, the best and quickest remedy is a form of clutch 
spinning brake. This may consist simply of a ftmall pait of leHtlier 
or of metal covered with leather so located on the frame members 
that the male drum touches against it when fully released. Or it 
may be something more elaborate as to size or construction or both. 
On many modern cars, in fact on practically all good car.-!, .some fonu 
of clutch spinning brake is fitted. Thus, in the llelt^Shaw design. 
Fig. 256, metal cones of small diameter are provided, while Fig. JiVi 
shows flat concentric discs of its Locomobile clutch. 

Cork Inserts. When cork inserts are used in a clutch, the 
insertion of new corks is not an easy job. A cork is a difficult. asA 
unhandy thiiyr to work with, and above all to ho\d stm^jA *^'^ ^^^^ 


while apphing longitiKlmal force to it. By making up a special 
tool with a tubular nicuiber having an innej taper, into which the 
corks are forced by means of a special plunger which forms the other 
part of the too!, this is simplified considerably. Tliis tool is shown 
in Fig. 2(i5, with suoh dimensions as would lie needed for a J-inch 
cork. It is advisable to make the small end of the tube { inch smaller 
than the cork, as this amount provides the proper compression, 
After being soaked in water for 10 or 15 minutes, the cork is dropped 
into the large end of the tube, and, with the small end in place 
against the cork opening in the 
clutch, a single stroke of the plunger 
will force the cork through the tm»l. 
incidentally compressing it into the 
hole in the ciutoh. With a few 
handlings any clever mechanic can 
soon become expert in the use of 
this tool, 

A more elaborate device, but 
one which works more quickly where 
there iM a great deal of this work, is* 



In Fig. 267, several other common clutch troubles and their 
remedies are suggested ; the parts shown in the illustration, however, 
are in excellent condition, in fact, new. 

When the right kind of clutch discs for a multiple^isc form are 
not on hand, new discs can be cut from leather to answer the purpose 
by means of the gasket cutter, shown in Fig. 268. This cutter con- 
sists of a pair of steel L-shaped arms, preferably forged, with points 
sharpened enough to cut the leather of the gasket material. The 
clamp has a point for the center of the circle on its under side, while 


tor -••J^ar m 


joint hoshir^ 
\feilaoe all Trussing 

,51tKi>31 W sHp joint 

Surfaced @' well oiled. 
Fig. 367. Clutch l^ouUes lUuMntrd 
the actual clamping is done by the bolt .or screw with wing head. 
To use for clutch discs, set the inner, or shorter, member to the radius 
of the inside of the outer discs and the outer, or longer, arm to the 
radius of the outside of the inner discs. By pressing down hard on 
the arms and rotating them at the same time, an annular ring will 
be cut out which will fit exactly. One hand should be held on or 
near the center, while the other hand supplies the pressure and 
rotating motion on the cutting ends. It should not be expected that 
the points will cut through in one revolution; on the conltM'y A'wfc 
first tirae around will just marJc out the section and \t. ViW weeA Ixcta. 


(i to 10 revolutions, with heavy pressure, to cut a leather disc. In 
time, the workman will be(.*ome sicillecl in the use of this cutter and 

Pig. 2118. Mplhod of Cullinii Fuing for DiiF CIuii-Iih it an Eii.crgvnrr 

have a knowledge of its hmtts, as well as of tlie method of keeping it 
in good cutting order. 

Adjusting Clutch Pedals. Some cars are mode with adjustable 
clutch pedals so the long- or short-legged driver can set the length of 
these to suit, but when no adjustment is provided and it is desired 
to change the length, some figuring must be done. To shorten a 
non-ad j nestable pedal, the beat way ts to take it out of the car and 


to^'ether at the other end. Thest* are bolteil in at J, where the pad 
V was formerly, and the pad moved out to the new end at B. In some 
such cases, where the sides of the pedal shank offer no groove to help 
hold the steel strips, it is necessary to put another bolt through them, 
as at C, to prevent the whole addition swinging about ^ as a cente^. 
Qutch Troubles Outside of Clutch. Frequently, there is trouble 
in the clutch when the basic reason for it is outside of the clutch 
entirely. Thus, failure of a clutch to engage or disengage properly 
is often the fault of ^e connecting rods and levers; wear in the clutch 
collar or in other parts; or the emergency-brake interlock may have 
been fitted so close that as soon as the rods are shortened once or 
twice to compensate for wear, it stands in such a position as to throw 
the clutch out slightly although the latter appears to be fully engaged. 
Another clutch trouble outside of the clutch is apparent slipping 
at comers, especially at turns on grades. On a turn — the road being 
cambered — the frame is distorted, especially with the combination of 
curve and grade. This may be sufficient to throw the clutch and 
driving shaft out of alignment just enough so the clutch face will not 
make full contact. This is most noticeable on cars with a single 
universal joint, in which case the distortion of the frame has more 
effect on the driving shaft. Similarly, a car with an unusually light 
or flexible frame will show this trouble very often, as the combination 
of curve and grade is too much for the light frame. 

Summary of Clutch Troubles 

Throwing in Clutch. Do not throw clutch in suddenly and cause 
rear wheels to spin. Such action is destructive to tires and throws 
great stress on the entire mechanism of the car. 

Lubricating Multiple-Disc Clutches. These are best lubricated 
by injecting oil into the opening for that purpose by means of an oil 
gun. A very light lubricating oil should be used. 

Multiple-Disc Qutches Failing to Hold. Inject three or four 
gunfuls of kerosene into the clutch housing and run the engine a 
little, thereby washing out the plates of the clutch. This will cut 
the giun caused by the oil. If, after this treatment, the clutch 
squeaks or takes hold too suddenly, lubricating oil may be added. 

Loss of Power. This is noticeable in changing from intermediate 
to high gear, in dimhmg bills, or in running througVi mwdA^ ox ^^^sA^ 


roads. The trouble is often the result of the clutcli slipping. The 
remedy is to clean the clutch with gatioHiic and, if the clutch is leather- 
faced, to apply castor oil after cleaning. Castor oil should never be 
used on the multiple-disc clutch- 
Failure of Clutch to Take Hold. This may be owing to a broken 
or weakened clutch spring, the dutch leather may be dama^'ni. 
clutch shaft may be out of hne or bent, leather may be gummed, 
or bearing may be seizing. 


Primarily, the clutch is used to allow the use of change-speed 
gearing; or, stated in the reverse way, the form of the transmission 
determines whether a clutch must be UHcd or not, there being cases in 
which it is not userl. Thus, where the frictional form of transmission 
is used, no clutch is necessary; the frictional discs act as a clutch 
and render another one superfluous. So, too. with the form of tra»3> 
mission known as the iitanetari/ gear, no master clutch is needed. 

On the other hand, the reverse of this docs not always hold. Anjt I 
form of clutch maj- be used witli the various other forms of tranamif- J 
sion, as the sliding gear; in fact, in actual practice every known kiotl 1 
of a clutch will be found coupled with the sHdinE-gear transmissioB. I 



ness has brought with it a stiffness which has rendered less repairs 
and adjustments necessary, despite lighter weight. The smaller sizes 
have brought about the simplification and lighter weight, and in 
turn have been produced in answer to the popular demand for lighter 
weight cars. In part, simplification has been- produced by unit 
power plants, now so popular. 


General Method of Operation. Of the different types of sliding 
gears, the first two subdivisions are not very closely marked, but 
blend somewhat into one another. The only real difference between 
them is the method of operation, the names serving to indicate the 
distinctive characteristics. Thus, in a selective gearset, it is possible 
to "select** any one speed and change directly into it without going 
through any other. So, too, in the progressive form of transmission, 
the act of changing gears is a "progressive'* one, from the lowest up 
to the highest, and vice versa. 

Selective Type. With the selective method of changing gears, 
it is possible to make the change at once from any particular gear 
to the desired gear without passing through any other. Of course, 
the car will not start on the high gear any more than in the other 
case, but shifting into low for starting purposes is but a single action, 
accomplished quicker than it can be told. So, too, when the car has 
been started, it can be allowed to attain quite a fair speed and the 
change to high made at once without going through the intermediate 

Progressive Type. Progressive gears, which are now little used, 
op)erate progressively: from first, or low, to second and from second 
to third, or high; in slowing down, from third to second to first 
and in this way only. This leads to a number of troublesome 
occurrences; thus, in stopping, it is necessary to gear down through 
all the higher speeds into low. If this is not done, when it is next 
desired to start the car, it will be necessary to start the engine, throw 
in the clutch, drop from the gear in mesh to the next lower, from that 
to the next, and so on down to low, throwing the clutch out and in 
for each change of speed. When first is reached, the car may be 
started. After starting, it is then necessary, in order to obtain any 
measurable speed with the car, to change back up the Ust, from low 


to second, from second to third, and bo forth. In this way the pixv- 
gressive gear is di^dvantAfceous, sinre its use means much gear 
shifting; but, on the other hand, the shifting is very easy for the 
novice to learn, as it is a continuous process, all in one diretrtioii. 
Modern Selective Types. To present some modern selective 
types of gear boxes ami point out their various differences. u<Ivan* 
tagcs, and ilisad vantages, refer to Vig. 270. This tjpe shows the 
three-speed selective gear used on llie Cadillac cars, which is but 
slightly modified from the t>-pe which has been used by this concern 
(or three years. This change should be noted, howe\'ct: the lay- 


and with another on the third shaft for reverse. The reverse gear 
is at all times in mesh with the fourth layshaft gear, so that on 
reverse the drive is through five gears instead of four. On high gear 
the drive is through the dogs, the layshaft being driven, of course, 
but silently, as it transmits no power. 

Four-Speed Type wUk Direct Drive on High. One of the tend- 
encies of recent years has been the gradual change toward more 
speeds, as shown by the increasing use of four-speed gear boxes. 

Other indications of this change have been the two-speed axle, which 
gftve double the number of gear-box speeds, with the ordinary three- 
speed and reverse transmission; and the electric transmission, which 
affords seven forward and two reverse speeds. 

Following this increase of speeds, the multi-cylinder motors and 
downward price revisions of the early part of 1916 brought about a 
ocHnbination which almost eliminated the four-speed gear box or at 
least removed it from all but the most expensive ol c&x% uA Vtcjov 



many of those. It 13 claimed that the eight- aiu] twelve-cylinder 
motors have so nuich power and flexibility that a fourth speed is 
rendered un^eces5a^^■. The four-speed gear box is more expensive 
than the tliree-speed box. and the lowered prices of cars have been 
instrumental in preventing \U continued use. At the same time, 
there was considerable lightening of weight all over the chassis, and 
the four-speed gear box had to go out of all but the biggest cars on 
account of its greater weight. 

Fig. 271 is a sectional plan of one of the few four-s|>ei*d geur 
boxes left. In this drawing it will be noted that the two-gear shafts, 
as well as the operating shafts, lie in the same horizontal plane. Tlie 
halftone rcprtKluction of the photograph of this drawing. Fig. 272, 


Four^Speed Type with Direct Drive on Third. In all the trans- 
missions shown and described thus far, the direct drive has been 
the highest speed. By referring back to Fig. 253, which show the 
Winton four-speed gear box, as well as the clutch, a point of difference 
will be seen. This has the direct drive on third speed, fourth being a 
geared-up speed for use only in emergencies, when the very highest 
rate of travel is required, and when a little noise more or less would 
make no difference. This arrangement of the direct drive and silent 
speed has long been a debated point, some designers favoring the 
direct-drive type with an over-geared speed for occasional use, while 
the opponents of this method say that this construction practically 
reduces the transmission to a three-speed basis, the fourth being so 
seldom used that it is practically negligible. They say, also, that the 
modern motor can attain a high enough speed, on the one hand, and is 
flexible enough, on the other, to permit its being used with the high- 
gear direct drive upon almost all occasions. 

Transmission Location. There are but four recognized positions 
for the transmission in the modern car. These are: (1) unit with the 
engine (unit power plant), (2) amidships in unit with clutch or alone 
in a forward position, (3) amidships in unit with forward end driving 
shaft or in a rear position, and (4) at the rear in unit with rear axle. 
Unit vnth Engine, The unit with the engine type is illustrated in 
an excellent manner in Fig. 273, which shows the eight-cylinder 
Northway motor, cone clutch, and three-speed transmission. Some 
idea of the compactness of this outfit, which is shown exactly as used on 
the Oakland car, can be gained from comparison with cylinder bore 
and crankshaft size, the motor being 3i by 4^ inches. The notice- 
able features of the transmission, aside from its compactness, are the 
use of double row ball bearings on the splined main shaft, with a 
Hyatt roller form for the spigot bearing (free end of main shaft) and 
very long plain bronze bushing for the countershaft unit, the latter 
being made as a single piece rotating on a single bearing around a 
straight fixed shaft. The countershaft, or layshaft, as it is some- 
times called, is placed below the main shaft. 

Another example of the unit with engine type is seen in the 
Grant-Lee three-speed gear box. Fig. 274, as utilized in the Hackett 
car. This is unusually small and compact, as will be noted by cttvsk- 
paring the size of the unit with the operating levers and peA«\. \s\v!^fc 





the clutch is not shown, its housing is, also the flange which attaches 
it to the flywheel housing to complete the power unit. A third 
example of the engine-unit power group is shown in Fig. 275, which 
shows the flywheel, clutch, and transinission of the Peerless eight. 
This unit transmits many times the power of the Hackett unit and 
is therefore much iaiger. In this unit the bearing arrangement is 
rather unusual, as roller 
bearings of the taper form 
are used on the main shaft, 
a straight roller for the 
spigot bearing, and plain 
ball bearings for the lay- 
shaft. The shortness and 
large diameter of the 
shafts should be noted. 

Additional transmis- 
sions in a unit with clutch 
and motor will be seen 
under Clutches, in Figs. 
251 , 252, and 254. 

Amidships AUme or 
irilh Clvtck. The amid- 
ships unit joined with the 
clutch, shown in Fig. 253, 
represents the Winton 
transmission and clutch. 
This is not a common con- 
struction on pleasure cars, 
although it is used on 
quite a number of trucks. 
On the amidships-clutch 

unit type, however, the _^ 

combinationisnotquiteso J"*™. Mtr^iiGn 

intimate as the one in which the two units are enclosed ina common case. 

Amidships Joined with Driving Shaft. The amidships unit 
joined with the forward end of the driving shaft is well shown by the 
Locomobile, Figa. 271 and 272. The universal joint *\lh. tiic Arwavfe- 
shaft pivots is seen Bt the left side of both theae v\ewa, \n. '^^ 


construction, wliicli is more' widely used ihaii the other omidship:^ 
arrangement, tiiere is usually a frame crus*-member at the point on 
which the rear end of the transmission is supported. This same 
arrangement is used on the Steams-Knight four-cjlinrler chassis, the 
transmission of which is shown in Fig. 276. In this transmission 
the stiffness of tlie eniss-member at the rear end of tJie transmission 
is also utilized to support the hrake ciriim of the frK)t-l)rake system. 


Rear Unit with Rear Axle. The position at the rear axle is 
not as widely used as a couple of years ago, hut those manufacturers 
using it have large outputs, so that a considerable number of these 
fiars are in use and considerably more are being added each year. 
One of these, the Studebaker, is shown in Fig. 277. This is a shadow 
<Irawing of the rear axle and transmission, showing the upper, or 
main, shaft of the transmission in full and the layshaft which is below 

it, partially. As will be noted, this position of the transmission 
calls for two operating rods, each the full length from the operating 
levers to the rear axle. The rod on the left operates the reverse 
and first speeds and that on the right second and third, or high, speeds. 
To make this shifting of gears and connection of levers with 
the actual position of the gears plain, Fig. 278 is also shown. In 
this figure the gear-shifting lever is placed in.the center and is shown 
solid in the neutral position and lighter in the other four '^osASon?.. 


Just below it, the traiismisHion is shown with the position of the 
gears for neutral, whilt? in the four corners, forrespomling to Uie four 
positions of the lever, tlic [wsitions trf the gears when the lcv» 
is in each one of the positions are shown. These positions indicutf 
that there is a driving gear and two sliding 
nieinl>er3 on the main shaft and four gears 
on the layahaft. At the left in the picture, 
the gear toward the rear is for reverse and 
another gear (not shown) is needed to com- 
plete the re\'ersal of motion. When the 
lever is swung to tlie left and forward, this 
group is completed and reverse s|)eed 

When the lever is swung to the left 
and pullfd backwards, the rtJir sliding 



nd over to the right^a furtlier movement to tlie front picks up the 
iruanl slidinfr gear and moves it back into mesh with the third gear 
n the la.\'shaft; tliis combination, as shown in the upper right-lmnd 
omer, gives second speed. When the lever is moved back, it moves 


Fi|, ZTS. Diagnnu Showing Working uf Sludebakcr Tni 

he gear forward, giving high speed and direct drive, as shounfi at tlie 
>wer right-hand comer. 

Interlocking Devices. Nearly all transmissions have a form of 
top lock on the shifting rods in tlie transmission, wliich holds the 
■ears in mesh as soon as they have been moved by the operator 
inti! he moves them again. In reality this arrangement simply 
irevents the gears from jumping out of mesh. Generally, the most 
imple arrangement which will hold the gears is used. In tlie ordinary 


form this arrangement consists of hardened steel wedges with liglii 
springs hack of tliem and deeji grooves in the shifting rods into which 
these wedges fit. 

In Figs. 271 and 272, the notches in the shiftjiig rods (sn he 
seen plainly. In Fig. 275, the bolt hewl A indicates the jocatinn 
of one of the shifting locks. In Fig. 277, .! shows the notches in 


iJmn imil 



)iiipany, the grooves in the rods being deep enough to accommodate 
is form in a.neutral position so that the rod can be started. But the 
ide hole in 'the central housing in which the pin is moved across by 
e motion of one rod, owing to the shape of the bottom of the groove, 
events the other rod from moving. 

Electrically Operated Qears. In substance, the electrically 
erated transmission has all the hand levers, rods, and other levers 
placed by a series of push buttons. When it is desired to change 
eeds, even before the actual change is necessary, the driver presses 
B button marked for the speed he thinks he will require. Then, 
len the actual need becomes apparent, he throws out the clutch 
d immediately drops it back again, all this forming but a single 
•ward and back movement of the 
>t. During the slight interval while 
e clutch is out, the electrical connec- 
>ns shift the gears automatically, so 
at when the clutch is let back, the 
ars are meshed ready to drive. 

Principle of Action. To explain 
Is action briefly, the gears are moved 
means of solenoid magnets, which 
3 nothing more than coils of wire, 
rough which an electric cifrrent from 
onvenient battery is allowed to pass, 
irough the center of each one of these 
lis passes an iron bar. When a cur- 
it passes through the coil, it is cou- 
rted into an electromagnet and draws the iron bar inward. As the 
her end of the bar is connected to the gear to be shifted, this move- 
jnt of the bar shifts the gear. Consequently, when the button is 
essed so that current flows through one of the coils, that action 
ifts the gear for which the button is marked. 

By referring to Fig. 280, this action will be made more clear. 
16 diagram shows but one pair of gears to be meshed, and the 
ttery, push button S, coil D, iron bar P, and clutch connection 
are all shown as simply as possible. When button S is pressed, 
rrent through the coil D will draw the bar P and mesh the 
ars as soon as the clutch has been thrown out, thereby closing 

Fig. 280. Sketch Showing How a 

Solenoid Moves a Gear When 

Current Flows 


the circuit nt M. Tlie application of this to an actual transmission 
is shown nmro in iletail in Fig. 281, which shows the dutch pedal 

C-H Electric Geu Shift 

and its cDrnifction to the six solenoids necessary to produce four 
ffirwani s|)cm!s, imc rcvirst' speed, and a neutral point. 

On the Mtcerinj; wlieel, Fig. 282, the control group of six buttons 
will he imtcd on the sniiill round plate at the center, with the addition 
of tlic hnrri liuttiin in the center. In Fig. 283 is another arrangement. 
IIS iii electric-control systems, the buttons are 


Pneumatic Shifting System. The pneumatic system of gear 
shifting is along lines somewhat similar to the electric system, air 
under pressure being used to move the gears instead of 'a hand lever 
and rod combination. For this purpose it is necessary to add an 
air compressor, a tank to carry the compressed air, and what is 
called the "shift" — really a complicated valve and a series of plungers 
. — to the car. The valve and plungers respond to a finger lever on the 
steering wheel, the same as the electric system responds to the but- 
tons. Air is admitted behind the plungers, which moves the gears 
as soon as the clutch is depressed. It is seen, therefore, that this 
system, like the electric shifter, permits the anticipation of the 
needs of the car. 

Railway Car Needs. All transmissions previously presented 
have had but one reverse. For gasoline railway cars, the inability 
to turn the car requires as many reverse speeds as forward, which 
means special gearing. Usually, this gearing is accomplished by 
means of a pair of bevels, each with a clutch, meshing with a single 
driving bevel. Obviously the two driven bevels will turn in different 
directions, and each will drive when its clutch is engaged. By 
shifting the clutch to the one which gives a for^-ard speed, all the 
speeds of the gear box become forward speeds; by shifting to the one 
which gives reverse, all the speeds become reverse speeds. 


Qeneral Types Used. While the number of adherents to the 
individual-clutch type of transmission is not as great as that of either 
the progressive or selective types of sliding gear, it holds its own; 
and, as time passes, it gains adherents. In this form, all the gears 
are in mesh at all times, and what has been called "the barbarous 
and unmechanical" method of clashing gears is entirely done away 
with. The individual-clutch type is operated on the selective plan 
but otherwise has nothing in common with the latter. 

The forms of clutches used vary greatly, as might be expected. 
The following are in use today: jaw clutches (both two- and 
multiple-jaw); internal-external gears, multiple disc, cone, and 
friction clutches other than the. multiple-disc form. 


Using Internal Dogs. One type in which the gears are engaged 
by internal dogs — ^the gears being in mesh at all times — ^has four sets 



of gears, those on the main shaft being keyed or otherwise fixed to I 
the shaft, while the gears on the jackshaft nm idle except when tfao I 
gear-shifting lever is moved forward to an engaging pontion, wbiA 
throws an internal dog up into a slot inside the gear. T\ua positioD | 
makes the gear one with the ^laft, and the power is transmitted I 
directly. The dogs in the latest form of this traasmissioa take the | 
form of hardened and ground steel balls. • 

Disc Type. Many of the eariy individual clutdi types of trans- I 
missions used discs, each gear having its own set and each set having 
sufficient surface to carry the whole power of the motor. While 
bulky, this had undeniable advantages, for it aUowed starting on < 
any gear. 

Contrncting-Band Type. While advocates of discs are numerous, 
other devices do not lack friends. Hg. 284 shows a form on the 


.gainst the gear by means of numerous fingers, Fig. 285. A conical 
tiding piece G or J expanded the fingers pivoted on M and H so that 
hey pressed against the 
Use within tiie gears D, 
K, or N. 

Internal' External Gear 
Type. Many of the gears 
.Iready given date back 
everal years, but the 
;ear illustrated in Fig. 
186 is more modem, 
.nd is being used today 
I y the International 
dotor Company of New York City and of AUentown, Pennsylvania. 
-The principle upon which this gear works, as shown by Fig. 286, 
3 that of the internal-external gear. The gears which transmit the 
tower are always in mesh. Each one of these is bushed and runs idly 
ipon the main shaft. Contained within each gear and an integral 
«art of it is an internal gear of twenty-four teeth. Sliding on the 

quared shaft are four 24-tooth gears; these are specially built for easy 
ngaging with the internally cut gears. 

To follow the letters placed on the parts of th\s %eaiT,V\^ «^^ 


is obtained b\- sliding the piece £-C~31 forward into gear 3-C-3i; 
this action swings the piece, shown dotted beneath, so as to throw 
out the clutch on the {ay shaft 2-C~52. On high speed, the two gears 
locked together arc the only ones to turn, all others being idle. The 
same piece 3-('~31, when slid to the right, meshes with the internal 
gear of the ■ictf>nd -speed pinion 2-C-160. This shding member sltdts 
upon H squared shaft, so the drive is poMtive, The action of the first, 
or slow s[)ccd. and reverse are the same as those just described, beinj! 
profiuced by the shifting of the clutch member 2-C-66. Attention is 
called tn tiie ball bearings used on this transmission, which are 
reniarkubleonly when it is remembered that this is a commercial truck 
transmission, Students of automobile construction will find many 
intcrc'stiiig constructional details in this illustration, which is a repro- 
duction of the manufacturer's working drawing. 

Still iiniitlitT sLiniliir form uses three cone clutches in the tfans- 
mission, that for the iiinh speed being augmented by a set of pins, 
or (logs, which, as the i-lutch gradually takes hold, slip into an equal 
number of holes in the ilriven gear. In this way, tlie two are made 
as oi)e, whifli makes slipping impossible— a very important feature. 

Transmission Operation. As has been pointed out previously, 
|)raiti<;illy all transmissions operate all gears by means of a long hand 


which loss of power shoilld be avoided. Gear-box lubricant generally 
is introduced in bulk by the removal of the cover, usually of a large size 
to allow of this. The outside parts carry their own grease and on cups. 

Transmissioii Bearings. By looking back at the various trans- 
missions shown, it will be noted that ball bearings are used most 
freely. Roller bearings in various forms are coming into use, as the 
shorter series produced in the last couple of years has shown 
designers that thist ype would produce a compact gear box, their size 
having previously limited their use. Plain bearings are not used at 
all on good cars. 

Transmission Adjustments. Few adjustments are needed in 
the modem gear box. However, provision for wear is made in the 
operating rods and levers, both within the case and without. In 
some cases the shafts may be slightly shifted endwise to secure 
better meshing of the gears after wear. Bearings, too, are arranged 
to shift slightly in an endwise direction to take care of wear in other 
parts and not so much in the bearings themselves. 


Method of Action. The planetary, or epicyclic, form of gear- 
ing offers many advantages, but, strange to say, the American 
people, although inclined toward simplicity and cheapness in com- 
bination, will not have it in this form, and, as a consequence, this 
excellent gear-reducing means is fast losing favor. The principle 
upon which all planetaries work is as follows: Connected to the 
engine is the first gear of the train. The second is one of a series of 
several gears; these are pivoted in a drum, which may be held station- 
ary by a brake band. The middle, or third, gear in the train, as well 
as the last, or fourth, is connected to another gear, a driven gear, not a 
driver. Considering but a single rotating train — there usually are 
three or more — the last-named gears form the fifth and sixth in the 
whole train. Gears two, three, and four have different numbers of 
teeth, as well as gears one, five, and six. Holding the band which 
holds the drum to which the gears are pivoted, allows each of them 
to rotate around its own axis, but not around the main shaft. This 
form of rotation gives one gear reduction. 

Another band holds another gear stationary and allows the 
three-gear unit to rotate around the main shaft as an axis; at the 



sani« titDP it liraves tbL-m frcv to nlso nitattr HrrHnxl llictr own iixrv 
This prodiioei another fiear mluction. ^Vnuttur form which is 
popular in so far as plaiu-tar>' g«ftr» tirr [wpulnr k> tlut in v\\]A 
tntenial gf-ars are ^ubstitutM tor noe 9ct of the jdaiiKU, from wbiiii 
Uie device ubtainetl its name. This <liws itoi roniplicnte ihr fk^icc 
any; in fact, ttu- only way in which it makes any change ia in thr 




ubtedly, when simplicity ia sought regardless of cost, the 
ive is the drive used. The cost with this form is not one 

but rather of other things which must be sacrificed if 
ive is used. 

Type. In the interest of simplicity, it may be said that 
n form of drive dispenses with the clutch, being of itself 
h and change-speed gear. The usual form which this takes 
g!e spur wheel contacting with another flat-face wheel, 
e must be i»t right angles, the car is nearly always chain 
! driving wheel 
be rear end of 
ihaft, and the 
tft across the 

the car. To 

more certain 
at the same 
in the differ- 
on, the cross-, 
nted upon two 
nt shafts, is 
d with a pair 
3, contacting 
}site sides of 
;r. As this 
luses the two 
ifts to turn in 

lirections, a gear is necessary- at the end of one of them, 
p^atest feature of the friction drive is the multiplicity of 
tainable, these being Infinite in number, since every dif- 
ition of the driven wheel on the dri\cr rcsult-s in a different 

consequently, a different speed. To obtain these various 
he wheel which meets the other edge-on is usually arranged 
meed up to and withdrawn fn>m the wheel presenting the 
e. In action, a motion of translation is given tu the wheel 
le time as the motion up to or away from the surface. This 
' translation changes its position and cooscqueotly its 



Over the threowheel arrangement, the use of the four-wheei 
arrangement possesses some undeniable advantages, particulari,;- if 
the two parallel driving wlieels are arranged to (i^i^■e the others in 
pairs. This arrangement makes tlie (Hrectinii of rotation of the 
wheels alike, and no intermediate gear to change the direction of one 
shaft is needed. A siaiplificatiou of this form utilizes the flywheel of 
the engine as the forward driving disc. 

Bevel Type. Bevels have many advantages over spur friction 
wheels. They are found in combinations, such as a single pair of 
bevels or three bevels, and in multiple combinations, without limit to 
the number of bevels. Fig, 288 shows the use of a single pair, hut 
in combination with a flat face on one and a spur attached to the 
other; this makes the whole consist of four wheels in reality. 

Another combination sometimes used is that of three bevels. 
One of the bevels has a flat face and a spur, making really five wheels. 
The spur wheel in e\'ery case takes the final drive, A direct drive 
on the high gear is obtained by the use of a cone clutch on this spur 
and another clutch with which it engages on the driving wheel. One 
bevel gives forward speeds, and through the other the various reverses 
are gained. The frirti<jn drive, although theoretically the simplest 


buggy field, the rope drive, the flat belt, the V-belt, the cloth-covered 
chain, and many others. With the collapse of the cycle-car boom, 
these went out of use. 

Hydraulic Qear. Janney-Williams, The hydraulic transmis- 
sion has been advanced as a cure for all automobile troubles, rep- 
resenting as it does the elimination of clutch, differential, and the 
driving mechanism. It consists of a pump to circulate the fluid, and 
one or two motors, usually attached to the rear wheels and propelled 
by the fluid. In the Janney-Williams hydraulic gear, which has 
been successfully used for some time in other fields, but has just 
recently been tried for automobiles in England, there are three 
similar pumps, one being used as a pump and the other two as motors. 
By rotating the driving ring so that it assumes different angular 
positions, the throw of the small pistons, of which there are nine in 
all, is varied from zero up to a maximum. Since the action of the 
fluid in the motors connected to the wheels is opposite to this, it 
amounts to varying the speed, the number of changes being infinite, 
as in friction gearing. 

Manly, Another hydraulic drive, of equal merit and of Ameri- 
can manufacture, is the Manly. This differs from the Janney- 
Williams only in the form of the motors; the fluid and its use are the 
same in both cases. This drive has for its object the securing of any 
desired speed of the driven shaft, either forward or backward, with- 
out changing the speed or direction of motion of the driving shaft 
and of transmitting the power to a shaft, which is either in line with 
the driving shaft or which lies at any angle to the driving shaft and 
is separated from it. It consists of a multi-cylinder pump having a 
variable stroke, which is attached to the driving shaft, and of one or 
more multi-cylinder motors having a fixed stroke, which are attached 
to the driven shaft, together with pipe connections, or passages, 
between them for transmitting the working iield. The various 
cylinders, both of the pump and motors, radiate equidistantly from 
a central crank chamber, and the pistons or plungers are connected 
to a single crankpin which is common to all. The fluid used is 
ordinary machine oil, its lubricating qualities and freedom from the 
danger of freezing admirably fitting it for such a purpose. When the 
system is once filled, the oil is used over and over agaiu, bra^^Vsvesstv- 
tinuous circulation from pump to motor througVi one set ol ^^^^^^ «^ 


passages, and hack again from motor to pump through aiuitluT srt. 
The stroke of the puiuii rnn.v W varied Ht will, hiil timt of tlic motor 
is fixed. The variation of the pump stroke iH ac-i'onipli.thetl liy a 
crank, on which an eect^ntrie bushing is mountw!, By revolving the 
bushing with reference to the crank, ita center line is hrought into 
alignment with the center of the shaft, and when this position is 
reached, no reciprocating motion is communicated to the pump 
plungers. The Manly is constructed iimler license by the American- 
La France Fire P'ngiiie Company, Rlmira, New York, and has proved 
its worth on \ery large trucks and on some of (heir fire apparatus. 

In recent jears a number of hydraulic transmis.<)ions have been 
brought out. but all these fact^ the fundanientul rfifBcuIty that when 
the pump chamber is liquid tight the friction is excessive. 

Pneumatic Drive. There bus been some talk of a pneumatic 
drive also, this idea not differing greatly from the previous one of 
using liquids. In this scheme H large tjink of compresMxl air is 
pnwidcd for the purjjose of starting the engine, helping to get up 
spi'cd quickly, and for use on hills when excess power is needful 
or at least helpful. If used as planned, it would allow of the elim- ' 
ination tif the reverse and would be utilized for braking aa weU, 



In fact, it might be said that the electric drive possesses so many 
advantages which are worth liaviiig, even at a sacrifice, and so few 
disadvantages that one is safe in figuring that a few more years 
will see the number of these drives double^ and possibly trebled. 

Electric Transmissions. While the drives just discussed might 
be called electric dri^■e8 and still be precise, the Owen magnetic car, 
which is constructed by the Baker, Ranch and Lang Company, 
makes use of an actual electric transmission, the Entz, at one time 
used in a Columbia chassis. This is so arranged that all speed 
changing is done by a small finger lever on the steering wheel, similar 
to the ordinary spark and throttle levers. The wiring formerly gave 


Fic 18B. Drawiu Shoinng SectioD through Oweo Mi 

seven speeds forward and two reverse, but a later construction will 
probably give about twice this number. 

As is shown in Fig. 289, this consists of an electric generator, the 
field magnet of which is connected to the engine crankshaft and takes 
the place of the flj-wheel, the armature being connected with the 
driving shaft. This transmits the turning effort of the engine by 
means of the current established in its circuit, due to the speed 
difference of its members on what constitutes the high speed. Any 
effort exerted by the engine on one member is transmitted, prac- 
tically without loss, to the other member, or armature. The clutch- 
generator member makes a very elastic clutching and tc&n^^'Uxnf, 
means, but caonot traasmit more than the fuU torque ol x!t\% «t\^vi.%- 


Fur higher torque, use is made of an electric motor, whose 
armature is mounted on the driving shaft and receives current from 
the first, or clutch, generator. 

In the figure, tlic clutch generator is shown at the left, its field 
part marked FR, the field winding FW, and the pole pieces PP. 
This portion rotates whenever the crankshaft revolves. Within it is 
the armature .1 secured to the continuous shaft S, which is con- 
nected througli the joint A' with the driving shaft to the rear axle. 

Tlic second part of the complete sj-stem is shown at the right 
ani] is practically a duplicate of the clutch generator. Its armature 
,'li is carried on the same shaft S as armature A. Outside this is 
the usual field part with rings FR, windings FW, pole pieces, and 
brushes B. 

Field FR can revolve without any motion of A ; in fact, it is by 
varying the relative speed of FR and ,1 that the different speeds are 



parable to the piece of steel f ', which is free to rotate and which will 
do so when the field rotates and attracts it. If this were connected 
directly to the driving shaft, as Fig. 290 shows the combination 

Fl|. 201. SbooimI Step 

would become a simple electromagnetic clutch and the car would have 
but one speed. On the level, one speed would be satisfactory, but 
in deep sand, on a heavy grade, or for any other severe pull, the air 
space between the rotating field and the armature would bring about 
the stalling of the engine. 

If we add a ccnventional 
electric motor just back of 
C, with its field fixed, or 
stationary, as at D. and its 
armature free to rotate with 
the armature shaft to which 
it b attached, about as shown 
in Fig. 291, C will not rotate 
as fast as B when meeting a 
stiff pull, although it will try 
to do so. A wire connects 
the commutator of C with 
the field coils D, and the 
electricity generated by the 
rotation of B relative to C, that 
air gap, is led through this wire to D where It acta aa power, rotating, 
E faster and thus acting as a booster on the propeWec ^VitAl. 

, the amount of slippage due to the 



By introducing variable resistaiic-e in the connecting wire, or 
ther series of wires, the speed may be varied from zero to the 
Aximmn, which, as it happens through this booster action, is 
nsiderably in excess of what it would be if the motor were dri\'ing 
rectly through on high speed without any electrical or mechanical 
^paratus. The variety of speeds can be an\-thing desired, and this 
rms the basis for naming it **The car of a thousand speeds". As 
matter of fact only seven speeds are provided for on the steering 
leel, which is shown in Fig. 292, but it is perfectly feasible to 
re up the car and arrange the quadrant to have twice this number 

any other number, as required. On the steering post quadrant, 
e additional positions of charging, starting, and neutral are to 

noted. The neutral position is that in which the engine is idling 
id the car standing still; or when the car is coming down a grade, 
e wheels are driving the motor which generates current in the reverse 
rection, so that the device becomes an electric brake, slowly but 
rely reducing the speed of the can The starting position connects 
e storage battery to the generator armature in order to revolve 
e engine shaft and thus start it. The charging position can be 
ed at any time to generate electricity for the storage battery. 
WTiile this description sounds verj' different, the chassis is not 
ilike the avera^ gasoline chassis with a mechanical gear shift. 

Fig. 293, showing a view of it from above, brings out. The small 
lit just back of the motor is a mechanical reverse gear which it 
.s been found advisable to use for one reason, because it gives 
I the quadrant speeds on the reverse, instead of the usual one. 
y' this arrangement the car has seven fixed speeds forward and 
ven speeds reverse, together with the possible variations of both, 
lich can be produced by the use of spark throttle and accelerator. 


Noise in Qear Operation. One of the most common of trans- 
ission troubles is a grinding noise in the operation of the gekrs. 
lis is heard more in bevels than in spurs, but in old transmissions 
id on the lower speeds it is heard frequently. A good way to 
liet old gears, after making sure that they are adjusted rightly 
d meshing correctly, is to use a thicker lubricant. If thick oil 
being used, change to haJf-oiJ and half-grease or pTii\eT«Jc\x ^ ^^^^$fc. 


III this rcspcft tlie repair man or amateur worker may take a ; 
Ifjif «iiit (if tlie l«Hik of second-hand car men, who are said to "load" i 
an old and very noisy transmission gear with a very thick almost , 
hard grease in which is mixed some shavings, sawdust, cork, or , 
similar lieadening; material. When this is done, a graphite grease is ■ 
;;enerully used, so that the shavings, cork, etc., would not show in 
case it was necessary tii take off the gear-fwx cover. This material 
Mill fill nj) all the inequalities of the gears and shafts so that tem- 
Iirirarily evcrvthing fits more tightly, and all the sounding board, 
or echo, cfTcct i-- t.ikm out of the transmission case, This sounding- 
hoard clfcit is fnlh as important as the grinding noise, for many 
rc;dly iiisignihc ml noisi-, are magnifietl by poorly shaped gear eases 



Gear PuUra^. One of the principal necessities for transmission 
}rk is 8 form of gear puller. These are like wheel pullers, except 
at they are smaller and more compact. In Fig. 294, a pair of 
ar pullers are shown. The one at the left is very simple, consisting 
a heavy square bar of iron which has been bent to form a modified 

Then, a heavy bolt is threaded into the back of this or bottom of 
e U. This will be useful only on gears which are small enough to 
' in between the two sides of the puller, that is, between the sides 
the U, which when in uae is slipped over the gear, the screw turned 
itil it touches some- 
ing solid, as the end of 
e gear shaft, and then 
e turning continued 
ntil the gear is 
reed off. 

While not as simple 
this, the form shown 

the right has the 
Ivantagcs of handling 
uch larger gears, and 
so of being adjustable. 
3 the sketch shows, this 
insists of a central 
ember having slotted 
ids in which a pair of 
.shaped ends, or hooks, 
e held by a pair of 
rough bolts. Then 
ere is a central work- 
g screw. To use, the hooks are set far enough apart to go over the 
«r, then slipped around it and hooked on the back. The central 
rew is turned up to the end of the shaft, and then the turning 
tntinued until the gear comes off. There are many modifications 
' these two; in fact, practically every repair shop in the land has 
i own way of making gear or wheel pullers. At any rate, everj' 
lop should have one. 

Pressing Qears on Shafts. The opposite of pulling off gears 
putting them on; very often they are designed to \ie a. ■^tcss. ^^-x 

Fie. 29G. Mctbod o[ Ptaung Tmumiuion Gttt 


whicli means exerting tremendous pressure. Every repair shop 
shouiii have some form of press for this and similar work, something 
similar to the form shown in Fig. 295. In this figure, the man is just 
begiiming to apply pressure to the shaft to force it into the lower 
j;ear. The table must be arranged for work of this kind with a solid 
spot when the shaft does not come through, and with a hole when it 
does. The work of pressing is usually done in a few seconds, while the* 
preparHtion, atigninent, and starting of the work takes perhaps half 
nil hour or more. It is work which should be done very carefully. 
One way in which arrangement can be made for pressing a 
shaft a coiisidcTiiliic dislaiice into a gear and, conversely, for pressing 
the shaft out of the gear is that 
shown in Fig. 296. This figure 
has the additional advantages of 
being simple, easily constructed, 
and cheap. A solid base is 
constructed with a pair of 
hinged uprights. These can be 
dropp)ed together with the work 
them, forming a mod- 
ed triiingle, the strongest 



For one thing, the edges of the gears may be burred so that the edges 
prevent easy meshing. When this is the case, any attempt to force 
the gears into mesh only burrs up more metal and makes the situa- 
tion worse. Whether this is the trouble or not can be determined 
very quickly and easily by removing the transmission cover and 
feehng of the gears with the bare hand; the burred edges can readily 
be distinguished. If this is the only fault, the transmission should 
be taken down, the gears taken out and placed in a vise, and the 
burrs removed with a cold 
chisel and file. 

Poor or worn bear- 
ings or a bent shaft or one 
not accurately machined 
may cause difficult shift- 
ing. If the bearings are 
worn, the difficulty of 
shifting nill be accom 
panied b\ much noise 
both in shifting and after 
The bent shaft is more 
difficult to find and equall> 
difficult to fix A new ^ 
shaft IS usualh the quick 
est and easiest way to 
remedy the trouble 

Sometimes the con 
trol rods or levers bind or 
stick so that the shifting 
is very difficult. In case 
the gears are difficult to 
"find" or will not stay in mesh, the fault may be in the shifter 
the transmission case. This usually has notches to correspond to the 
various gear positions, with a steel wedge held down into these notches 
by means of a spri&g. The spring may have weakened, may have lost 
its temper, may have broken, or for some other reason failed to work. 
Or with the spring in good working condition, the edges of the 
grooves or notches may have worn to such an extent as to let the 
wedge slip out of, or over,' them readily. 



Cleaning Transmission Gears. When tliu transmission is taken 
out of tiie case uml has to be taken apart, ami particularly if it lias 
not been cleaned fnr a long time previously, it is advisable to clean 
all the parts thoroughly before attempting to work with them. 
The best way to clean the parts is to have a special cleaning tank. 
In Fig. 297 one of these is shown, which is not unlike the baskets 
used in some hardening processes. It consists of a deep metal or 
metal-lined tank and a basket or tray, which is an easy fit in it, 
sus(>endeiJ from abo\'e by wire cables. The cables arc brought 


drain, all trace of kerosene will disappear, while the gears, shafts, 
and other part^ will be like new. 

Lifting Out Transmissions. When the trouble has been found 
to be in the transmission case or in some part that necessitates com- 
plete removal, it is often a tremendous job to get the unit out. Some 
units are attached from below and are not so difficult to detach. 
TTiey are lowered by means of a platform of boards set on two or 
more jacks; But when' it must be removed from above and uo 
overhead beam is available, the hoist shown in Fig. 298 will be found 
very handy. As will be seen from the sketch, this hoist is simply a 
triangular framework constructed from angle iron to have the 
minimum height which will allow removal of the unit. The chain 

Tit- 200. Ti 

fall is attached to a hook in the center, and the chains put around 
the case. When lifted up close into the V of the framework, the 
whole transmission can be'put onto horses and moved along the 
chassis, or boards can be put under it and over the chassis frame to 
allow it to be worked there. Or, if desired, it can be lowered onto a 
creeper or other low platform with wheels and moved out of the way. 
This rising can be used for many other similar purposes, although it 
is not suitable for the removal of an engine, radiator, or other part 
or unit which extends far above the chassis frame. 

Transmission Stands. When the transmission has been 
removed, if the work to be done upon it is all extended, a stand to 
support it is desirable; in fact, a necessity, if the work is to be done, 
right. A pair of stands are shown in Fig. 299, l\ie otve aX \li\«\^X 



is made from pipe fittings and angle irons in such a way that the 
width between the rails can be varied to suit the transmission or 
engine. The stand at the right is more of a specialized type. It is 
constructed for a certain transmission and has clips to support it 
in the same way that it is held in the chassis. The latter frame may be 
smaller and more compact than the former, but the wide range of 
uses to which the former can be put make it more desirable in the 
average shop. 

Working in Bearings. When a great many bearings of an\' 
one transmission are fitted, it is well to make a jig for working in 
the cases to an exact size for the bearings, whether these be over- 


Fie. 300. Method ol flttiua Tmumi 

.^ A 

sizes or not. Such an outfit. Fig. 30(), ^hows an aluminum trans- 
mission case with a pair of jigs for scraping its bearings into the case. 
These jigs are made of steel and are constructed to a very accurate 
size, the surfaces being hardened so tliey will show no wear. The 
jigs are painted with Prussian blue, put in place and turned, the 
markings scraped by hand, the jigs again put in place and turned, 
and this process repeated until a perfect bearing surface is obtained. 
Starting with an imknnwn size on tlic case and a known size of bearing 
which must go in it, a few of these jigs will soon save their cost in 
labor and time, by quickly \>rod\iciiig the necessary size of case to 
take the bearings. 



> Saving the Balls. If a great many ball bearings, particularly 
from transmissions, are used, and many bearings scrapped, it is 
advisable to save the balls. These balls will come in handy later for 
replacement or other uses. 
Moreover, balls are expen- 
sive, and good ones are hard 
to obtain. A handy way to 
take care of balls, without 
much work beyond cleaning 
thoroughly in the kerosene 
tank, is to construct a cab- 
inet like that seen in Fig. 301 . 
There are four drawers — or 
more if desired. The bottom 
of each drawer isa steel plate 
drilled as full of holes as pos- 
sible of the next smaller size, 
that is, a clearance size for 
the next round figure size. 
Then the cabinet does the sorting, all balls being put into the top 
drawer. The next smaller size is retained in the second drawer, the 
third size in the next, and so on. When using balls out of these 
drawers, the micrometer should be used to determine their exact size. 
Handy Spring Tool. In the Ford transmission-band assembly 
there are three springs which it is difficult to assemble because of 
the trouble in holding so many things at once. To eliminate this 
trouble, the tool, shown 
in Fig. 302, made from 
flat bar stock, can be 
constructed. The han- 
dles, if they could be 
called that, are pivoted 
together and carry a kind 
of fiat jaw with three 

, , Fig. 303. Huidy Sprinc Too] lor Ford Anembly 

notches at one end. 

When the two of these are squeezed tt^ther by means of the screw 
and handle at the other end, the flat plates will hold the three spring 
tightly enough so that all can be inserted in tWit ^^^^1 ^msv'wsKi 


at oiu-e by iisiiit; txit one hand. Tools of this kind, which save 
a jjreat lieal of tlie workman's time and thus save both time and 
money for the owner <•( the car, should, and in fact do, distinguish 
the well-c<|iiii>ptit rejiair shop and garage from the old-fashioned 
kind which is iti tlic Imsiness only for the money and not too par- 
ticuliir how it is Kotten. 

In transmissions of tl;e planetary tj^pe, there is little or no 
trouble except witli the bands. If these are loose, the gears will 
not enfiiific ami the desired speed will not result. If they become 
soaked with {;re;i-,r, oil, or water, they will not work as well as if kept 
■ of exressivc grease, will slip continually. If 
IK'S worn, it should be treated just as a brake 
ccteii for wear and found not badly worn but 
leaned in gasoline and then in kerosene, after 
w, or coarse file may be used to roughen it. 
mis can be fixed temporarily — sa\', enough to 
where tools, materials, and facilities for doing 
(' by sprinkling them with powdered rosin or 
inner should be used sparingly because it will 
■ I )(■ fjruh hold when forcibly applied, and at timeii 

clean t 
the ba 



in t 





1 insp 


t ma. 

he c 



aw, 1 


Son let 


- «ri'i 

s\- hii! 

^et till 

r to i 


the w, 


ire a 





I'll,- t. 



off nicely and are well hardened at these points — a cutting action 
which gradually wears u high hurr in one or both gears is liable to 
be set up. When the two are in mesh, the burrs are on opposite 
sides and contact with the meshing gear. This contact will make 
a continuous noise. Its remedy is the removal of the gear, the 
filing off of all raised portions, the filing or grinding out of all low 
spots cut into the teeth, and subsequent hardening to make repetition 

If the gears have worn at the center hole where they slide on 
the shaft, either in the round hole or at the kej'way, this must be 
fixed at once. In the former instance, the gear can be bushed, and 

I^g. 303. TmumiHion Traubin Illiulnled 

the bushing bored out to fit the shaft, while in the latter, a slightly 
larger key may be fitted into the shaft and the ke\'way may be recut 
to accommodate it. Where the keys liave been let into the shaft, 
they may become worn in one spot or at the ends. If the wear is all in 
the key, it can be replaced with another of the same size made slightly 
harder in the process. 

If the main bearings are of the roller type, the wear may be 
taken up by readjusting the position of the roller on the cone, but 
if they are of ball or plain bushing form, replacement is almost 
the only remedy, unless it happens that in the case of a plain bush the 
bush is split, so that something may be filed off of the t«o cntiXja.'iCwv.^ 
sides, and the holes trued out to this new size. \u V\\a.\, iia.'sft, ^I^^' 


advice previously given under the subject of Plain Engine Bearings 
will be applicable. 

Play in the shifting rods may be traced to one of two things: 
looseness at the connection of two rods or of a rod and a lever; or 
looseness in the bearings. The former inevitably requires a new and 
slightly larger pin driven into the place occupied by the previous 
member. Loose bushings will mean new ones if the trouble is serious, 
for this form is almost always of the solid and non-adjustable ty[>p. 
In many cases where wear occurs on a solid plain hearing Used un 
the end of a plain round shaft, if peening cannot be resorted to. 
the shaft may be turned down a very little bit, say ^ inch, tlie bushing 
turned out an equal amount, and a thin sleeve bushing made of this 
thickness all around and forced into the pre\noas member. This 
saves reboring the case, which is an expensive and difiicult job, 
while both the shaft and bushing jobs are simple ones. 

If a serious defect develops in the case, it may be deanod out 
and welded. This is not a job for the amateur, but the closing of a 
simple crack, no matter how long, would be an easy proposition for 
the owner of a welding outfit; moreover, it would be a very short 
quick job. Autogenous welding should always be resorted tu as soon 
as a crack tir break is detected, for this mav save the exDen.te and 


Adjusting Annular Bearings. Makers recommend that the 
irnier race be pinched so tight that movement is impossible; the 
outer race is sometimes allowed a little freedom — .002 to .003 inch. 


Since the whole subject of transmission concerns itself witH 
gears, it will not be out of place to discuss the gears themselves 
and describe the many different kinds in use. Speaking broadly, 
the gears used may be classified according to the position of their 
axes, relative to one another. Thus we have axes parallel and in the 
same plane; parallel but not in the same plane; at right angles and in 
the same plane; at right angles and not in the same plane; at some 
other angle than a straight or a right angle and in the same plane; 
and the same, but not in one plane. These classes give us the forms 
of gear in common use, viz, spur gears, bevel gears, helical gears, 
herringbone gears, spiral gears, and worm gears. 


Before discussing these various kinds of gears, it may be wise to 
familiarize the reader with the special features of different types of 
gear-cutting machines. Formerly, the teeth were cut, one gear at 
a time, in the milling machine, this being practically a hand opera- 
tion, since all movements of the gear or cutter had to be made by 
hand. Later, improvements made it possible to cut more than one 
gear at a time, which resulted in lowering the cost, but did not 
eliminate the hand work. 

Step by step special machinery was developed for this work, 
until finally a perfected machine was brought out which did all the 
work. With this machine, the workman placed the cutter on 
the machine spindle, set the gear blanks into position, and started the 
machine, after which it went on automatically, cutting tooth after 
tooth to a correct shape, until the gear was finished, when it was 
again necessary for the workman to shut it off and, after taking out 
the finished gears, put in a fresh supply of gear blanks. 

Many machines have been devised and perfected in recent years 
owing to the demands of the automobile manufacturers. By having 
a battery of gear-cutting machines handled by a single man, the 
cost of gear cutting has been brought down to the absolute limit 
in addition to a decided gain in gear accuracy. 


Whiton Qear-Cutting Machine. The Whiton automatic geaN 
cutting machine is shown in Fig. 3(M, The cutttT is carried by 
the spindle A, which is juurnaled in a saddle B sliding upon the 
swinging carriage C, and is cupablc of adjustment at any angle neces- 
sary to cut bevel gears. The machine, as shown, is arranged for 
cutting spur gears. The cutter ardor .1 is driven by the pulley }l ill 



Brown and Sharpe Qear-Cutting Machine. Fig. 305 repre- 
sents a Brown and Sharpe gear-cutting machine. The gear blaiik is 
carried on an arbor fitted to the horizontal spindle A and supporte<l 
by the outer supporting bracket B. The indexing mechanism is in 
tlie rear of the indexing wheel C. The cutter is carried by the cutter 
s|>in<lle D mounted in the traveling carriage E. In smaller machines 
the base upon which this carriage slides is pivoted so as to be 

set at any required angle for cutting bevel gears. The machine is 
entirely automatic in its action. It has an attachment for cutting 
internal gears. 

Automatic Qear-Cutting Machine. The automatic gear-cutting 
machine built by Gould and Eberhardt is shown in Fig. 306. It is 
of the same type as that built by Brown and Sharpe and possesses 
acme excellent features. The gear blank and cutter are mounted in 


a similar mannrr. and the adjustments are made at much the same 
points. It is furnished with attachments for hobbing worm gears 
and for cutting racks and internal gears. The one shown 13 not 
adapted for cnttiiig bevel gears. 

Becker Gear-Cutting Machine. The Becker Milling Machine 
Company gear-cutting machine, Fig, 307, is of the milling-machine 
type, It WHS designed by Amos H. Brainard, a builder of milling 
machines. The gear blank is mounted upon an arbor fitting a taper 


the change gears at C. These are driven from the cone pulley D by 
means of the vertical shaft E with a very gradual but continuous 
motion as the vertically reciprocating cutter F forms the teeth on 
the blank, gradually rotating in unison with the rotation of the blank. 
The Teciprocating movement of the ram carrying the cutter is pro- 
duced by suitable mechanism within the casing H operated by the 
shaft G. The machine is automatic in its action and cuts spur gears 

Cairtttg bI Btcker Milling Uaehnu Company. Hydi Parle, AfoiHckiucUi 

and internal gears. A modified form of machine is adapted to cutting 
the teeth of racks. The cutting action is that of planing. 

Qleason Gear Planer. The Gleason gear planer is shown in 
Fig. 309. It is an excellently designed machine with a single tool 
having a narrow rounded cutting point for planing gear teeth. The 
gear blank A is mounted on a horizontal spindle having at its rear 
end a suitable automatic indexing mechanism B. The tool C is 
carried in a redprocating too! block D which traveb upon a swing- 


ing carriage pivoted at E directly under the apex of the base cone of 
the gear blank. Tlie exact curve and direction of its feed are con- 
trolled by one of the formers, mounted upon tlie triangular former 
carrier, which may be rotated so as tu bring either former tip to its 
operative position, making a rest and guide on the outer end of the 
swinging carriage for the friction roller K. Of the three former*, nw 


Bllgram Qear-Planing Machine. The Bilgram gear-planiag 
machine, shown in Fig. 310, operates upon a principle similar to that 

ESr-PUiniac Michioe 

of the rnechine just described, but with this important difference. 
In the Gleason matihine, the tool moves so as to trace the exact 
contour of the side of the gear tooth, in addition to its reciprocating 


movement for cutting. In the Bilgram machine, on the other hand, , 
the tool has only a refijirocating motion, while the gear blank and ' 
its siipporticig median iaiii are given the roiling motion similar to that 
imparted by one rotating gear to another, which is that of a rolling 
cone. To accomplish this motion, the axis must, in the first place, be 
moverl in the manner of a conical pendulum; therefore, the bearing i 
of the arbor which carries the blank is secured in an inclined position 
between two uprights to a semicircular horizontal plate, which can be 
nseillated on a vertical axis passing through the apex of the base cone 
of the blank. To complete the rolling action, the arbor must, in the 
second place, receive simultaneously the proper rotation; this effect 
is produced in the machine by having a portion of a cone (correspond- 
ing with the pitch cone of the blank), attached to the arbor and held 
by two flexible steel bands stretched in opposite directions, one end 
being attached to the cone and the other to a fixal part of the mech- 
anism, thus preventing this cone from making any but a rolling motion 
when tlie arbor receives the conical swinging motion. In the engrav- 
ing, . I is tlie blank to be cut, ii the ram carrying the cutting tool, and 
C the indexing and rolling mechanism. 


in Fig, 31 1 . This is the final drive and reduction gear of the Autocar 
commercial cars, made by the Autocar Company, Ardmore, Penn- 
sylvania. In this gear, it will be noticed that the drive from the engine 
is through bevels to an intermediate shaft and that the final drive 
is by spur gears. 

Helical and Herringbone Gears. In situations where quiet 
running is deemed necessary, the use of a helical gear frequently finds 
favor, since it accomplishes the desired result, although the cost of 

ComUnattoD ol Gem in the Autoar Final Drira 

cutting is high. Of late, these gears have come into general use for 
camshaft drives and similar places. A pair of helical gears set so that 
the helices run in opposite directions forms a herringbone gear. 
This is even more quiet in its action than the single helix and pos- 
sesses other virtues as well. One well-known firm has adopted it for 
camshaft driving gears and makes it as described to save cutting- 
cost, as the cost of cutting a true herringbone would be prohibitive. 
So a pair of helical gears of opposite direction are set back to back and 
riveted or otherwise fastened together, forming a herringbone gear at 
a low cost. Both of these may be used when the two ab&fts &.'e% ^t- 


allel and in the same plane, but for all cases where the shafts are 
neither in the same plane nor parallel, some form of spiral gear must 
be niaile use tif. 

Spiral Gears. Spiral gears, as such, are not generally under- 
stiiiid, but that variety of the spiral known as the worm gear is 
very simple and easily understood and it has attained much popu- 
larity within the past few years. This popularity has been due, in 
part, to su[)erior facilities for cutting correct worms and gears, but, in 
the main, to a superior knowledge of the principles upon which the 
worm works and uf the things which spelled failure or success. Thus, 
one of the earliest experimenters in this line laid down the law that the 
rubbing velocity should not exceed 300 feet per minute if success was 
desired or in rotary speed about 80 to 100 revolutions. For auto- 
mobile use, this was out of the question; but later experimenters 
found that these results only attached to the forms of gear usetl by 
the early workers and did not apply to a strictly modem gear laid 
down on scientific principles. 

The mistake made was in the pitch angle of the worm, which 
was fornifrly made small, nothing over 15 degrees being attempted. 
This wiL.s tiie item tliat was at fault and that caused this very useful 

eHicicnt nirxlL- of ilriving to fall into disuse. As soon as this 



Woods electrics; Pierce, Packard, Riker, Mack, Atterbury, Blair, 
Chase, Gramm, G.M.C., Hulburt, Moreland, Standard, Sterling, and 
other trucks; Dennis (English) busses and trucks and Greenwood and 
Batley (English) trucks. 

nr af Timkra-DttToii A 

Spiral Bevels. The spiral bevel is a new development, having 
been brought out in 1914 as a compromise between the worm and the 

straight bevel. As such, it is supposed to have pratticaliy all the 
advantages of both, except that it does not afford the great speed 

> I; 


where it will be noted that the worm^ear housing in the center 
is actually higher than are the brake drums at either end of the axle. 
This, too, despite the fact that a truss rod passes beneath the 
center of the axle. For heavy trucks, especially, and for electric pleas- 
ure cars, the worm has proved an ideal drive. In these situations, 
there is the condition of high-engine or electric-motor speed, coupled 
with low-vehicle speed requirements, which necessitate a considerable 
reduction. As pointed out, the worm gives this in a small space. 

For 1916, the very apparent tendency in final drives is toward 
spiral bevels for pleasure cars and worms for electrics and trucks. 
The tendency toward spirals is very great, amounting practically 
to a landslide, 57 per cent using it against 10 for 1915. The devel- 
opment of special machinery for cutting these gears and the under- 
standing of their use has brought this about. In the truck field 
there has been a similar movement toward the worm, due to similar 

Gear Pitch and Faces. The manufacturers of transmissions and 
of gears for them do not agree as to the best gears. Neither do they 
agree as to which gears are most quiet or most efficient. In general, 
coarse-pitch stub-tooth gears are gaining faster than any other form. 
The 6-8 pitch is fairly general for gears of j-inch and J-inch face, 
and 4-5 pitch for wider gears. One manufacturer, Warner, con- 
siders the finer pitch gears and narrower faces as less likely to make 
noise, since they will not distort as much in hardening as wider gears. 
In this, other manufacturers agree, but there are some who claim to 
have had both quiet and noisy operation with both fine and coarse 
pitch. The tendency toward compactness has not increased 
transmission-gear faces any appreciable amount, nor has the 
increased use of better steels and better hardening processes lessened 
the size of tJie four noticeably. , 

Gear Troubles. Most of the common gear troubles have been 
previously covered at the end of transmissions. There is not as 
much trouble with gears today as there was several years ago. This 
is due to better design, better materials, better processes, and better 
assembling on the part of manufacturers and to more skill in handling, 
caring for, and adjusting on the part of owners. Of course, the 
repair man still finds plenty to do, but the percentage of gear repairs 
is relatively less than ever before. 




Q. Why is a clutch needed? 

A. Tilt' chilcli is needed to disconnect the rest of the drive 
friiin the engLne. The jjasoline engine cannot start under a load but 
must first (jet up speed. By means of tlie clutch, which can be 
thrown oLit, the eTipiiie is allowed to run alone and get up the nei'es- 
sary speed, then the \tmi\ or drive can be thrown on. This is just as 
true of the stjitiiULary gas engine as of the automobile, motor boat, 
or aeniplane power plant. 

Q. How does the clutch act? 

A. It is designed and constructed so that the amount of frictinn 
surface, with the spring pressure provided, is sufficient to transmit 
the whole power of the engine (and slightly more as a factor of 
safety) when the clutch is in. In addition, it is so designed and cfin- 
strueted that when the clutch is out the spring pressure is taken up 
in such a way us tn he self-contained, that is, its thrust is carried tu 
a member milsiiic of the clutch itself which is able to withstand this 
thrust. Ill this way. when the clutch is out, the engine is entirely 


Q. What are the two divisions of the cone form? 

A. The cone form is made in two ways, the direct form and 
the indirect form. The direct form has the cone introduced directly 
into the flywheel, which is tapered inwards for this purpose. This 
makes it a very simple device to construct, the machining of the fly- 
wheel forming the female portion of the clutching surface. The indi- 
rect form, or inverted cone, differs in that the female portion is made 
as a separate flange bolted to the fl>nvheel and tapering outward. 
The cone is placed inside of this, so that it works out against the 
clutching surface instead of in against this surface, as in the direct type. 

Q. What are the relative advantages of the two forms? 

A. The indirect is little used now, although it was popular years 
ago. The extra bolted-on inverted cone adds to the fl>nvheel weight, 
for it is large and heavy and gives considerable flywheel effect. How- 
ever, the fl^nvheel is simplified. The spring is enclosed between the 
fl^'wheel and the cone, this being considered an advantage in the early 
days but now considered a disadvantage because it is inaccessible for 
inspection or adjustment. The cone is pushed in — away from the 
clutching surface — to disconnect it, while on the more simple direct 
t\T>e, the cone is pushed out — away from the clutching surface — to 

Q« What are the divisions of the disc clutch? 

A. Disc clutches are generally grouped according to lubrication, 
those which run in oil being called wet, and those which run without 
lubricant of any kind being called dry. In addition, a distinction is 
generally made between the disc clutch with a very few plates (one, 
two, or three), usually called a plate clutch, and the form with many 
plates (10 or more) which is called a multiple-disc clutch. Either 
plate or multiple form may run wet or dry. 

Q« Explain the difference between the wet and dry multiple 

A. In the wet form, the plates, or discs, are plain steel and are 
submerged in oil, the entire clutch housing being filled with oil. The 
clutch discs work steel face against steel face, the action of the spring 
when the clutch is let in gradually squeezing out the oil from between 
the faces. This gradual squeezing out of the oil gives this form its 
gradual-application quality, for with aiix or seven pairs of discs the 
squeezing-out process takes an appreciable length of time. Iw. IVnr 


dry fonii, the plates are iirdmariiy faced with a special clutching 
surface of woven asbestos fabric similar to brake lining, this being 
placed upun every alternate disc, that is, the actual clutching surfaces 
consist of steel and fabric alternating. The general method of con- 
struction is to take one set, say the inner discs, and face both sides of 
each one. Then none of the outer discs are faced, so that when the 
clutch is assembled there is a steel face against each fabric face. This 
form is run absolutely dry; in fact, considerable pains is taken in 
design and assembly to keep out any form of lubricant. 

Q. Explain the difference between the plate and the multiple- 
disc forms. 

A. In the niultiple-tlisc form, a considerable number, say II, 13, 
15, or some such number of discs, is used; the smaller number, as 5, 
6, 7, etc., being the drivinj!;, and the larger half, as 8, 9, 10, etc., being 
the driven. In the plate form, a very small number of plates of the 
largest size which the flywheel will allow is used. As a rule, the fly- 
wheel inner surface is machined out to form one of the surfaces, the 
engaging or disengaging member another, and a single disc between; 
or, perhaps, another^e disc is fixed to the flj-wheel and two discs 
used between tliis and the other two surfaces. The plate form has the 


ably called for complete enclosure, making adjustments and replace- 
ments difficult. The smaller springs are usually placed outside, 
so that they can be adjusted or replaced easily and quickly. It has 
been found, too, that by using a large number, say 6, 7, or more, 
distributed around the clutching surface, a much lighter spring pres- 
sure can be used with equally good effect. In fact, many modern cars 
have so light a clutch spring that it can be disengaged with one finger. 

Q. How does the contracting-band clutch work? 

A. It has two half-bands which the clutching mechanism draws 
tight against a drum. In effect, a contracting-band clutch is like a 
band brake, except that the braking band is in two halves and operates 
from the center instead of from the exterior surface. 

Q. Is this a popular form? 

A. No. It is rapidly going out of use; only one or two American 
cars, with perhaps the same number in Europe, are now using it. 

Q. How does the expanding-band clutch work? 

A. In a somewhat similar manner to the expanding, or internal, 
brake; that is, it has two segments of fairly stiff metal section, which 
the movement of a cam, or expander, presses outward against the 
inside of the clutch drum (or inside face of the flywheel). This cam, 
or expander, is worked by the movement of the clutch pedal, or spring 
— outward so as to expand the band and take hold of the drum for 
engagement; inward so as to allow the band to contract. 

Q. Is this type gaining in popularity? 

A. No. On the contrary, it is losing so rapidly that there are 
practically no cars built in this country with it, although a number 
of old cars with this form are still running. 

Q. What is the usual position of the clutch? 

A. Within the flywheel. This saves a great deal of space, a 
number of parts, and considerable weight. 

Q. Why is this position used so freely? 

A. Partly because of the savings just mentioned, and partly 
because of the rapidly growing use of unit-power plants which forces 
this location. With the engine and transmission as a unit and the 
necessity for the clutch being between them, the fl>nvheel interior is 
about the only place for the clutch. 

Q. How can the surface, and thus the transmitting power, of 
clutch discs be increased? 


A, By the \ise of other than plane snrfac'es. Thus, in the Helc- 
Sliiiw fnrm ejuh disc is inatie with a small cone projecting from il. 
The outside of this engages with the interior of the cone on the next. 
Other forms have half-cone or other inclined surfaces and half-plane 
surfaces. As a Htraisht line is the shortest distance between two 
points, so a plane flat surface gives the smallest area between any two 
points in parallel surfaces. From this it is apparent that any surface 
not plane offers a greater area than does the plane one. However, 
the plane surface is so much easier and cheaper to make, use, replace, 
etc., that it has gradually driven out all these forma with greater sur- 
face despite their advantages in the way of transmitting power. 

Q. What causes a slipping cone clutch? 

A. A slipping cone clutch is generally caused by oil, grease, or 
other lubricant on the clutching surface or by a weak spring. 

Q. How can this be remedied? 

A. The snrfiue can be cleanetl with kerosene, then with gaso- 
line, and dried. Or, if the surface is glazed, it can be roughened by 
using a file. Or, if the slipping occurs out on the niad and no tools 
are available, any powder or fine material which will give roughness 
can be used. It is possilile to get home with a slipping cone clutch 


2. Tell how you would adjust the Steam^-Kniglit dutch sprioj^. 

3. Give the method of removing and replacing a clutch spring 
in the Warner clutch. 

4. If springs under the dutch facing of a cone dutch do not 
produce gradual engagement, what is the matter, and how would you 
remedv it? 

5. How does the Cadillac dutch work? 

6. How does it differ from other dutches of the same type? 

7. How would you lubricate a dutch bearing, with what, awl 
how often? 

8. Describe a quick. ea5>' method of replacing eorib in a dutch. 

9. How would you ocAstruct a dcr\ioe to hold dutdi springs 
while replacing them? 


Q. l^lat is Ae pwpofe of tlK 

A. To aDow variatJoflDf in tLe sp«iwl of the car fonraid twm tbe 
lowest to the higlaesau and for m'erw*. without var>iQg the OMAor 
speed greatly. 

Q. ^^ 
away ^ 

A. Tlie knnet;! f^iebd uwfi in car& ordinajily would xrA be po6^ 
sible with tbe ppeeieiit engine, sinoe it «Muld XKft be vaiuounA down 
slow cnoo^ AgaixL if the gearing were sudi a^ Vj give tbe psmmA 
lowest car sptoeds with the ^sD^cut low speed, tbec tor nttrimwn e^pne 
^leeds tbe hi^iiest potsuhk: car Hpeed would be ver^- k*w. In abort. 
gei^ring is iieoesB;^^^' to give a greai^r vanatioD tbac is possible with 
the engiiie alone. Further, reverw could not be obtained without 
addjtirinal gearE> and thi£> would ueoesaitate alsc^ a method uf ^uftipg 
the revtTwt gear into, and out of. itie^. Tliu:^. all Uie requiftaneut^ of 
the modern gear tranamission would be neoeaaar>' fur revove akioe. 

Q. Sbam Inlfer aar of fipma Ifer m^uuMSt} of 

A. The dnrumferenee of J^i-ioch wlteels is 1%.^ incsie&. or 1 1 .4 
feet. With the engine geared direct u* the wboek. the speed of the 
latter would be directly proportional to tbe former, conf&idenng the 
^ear reduction. If an average preMmv-day gear reductioD of o.8 to 1 
be cxnaidcnd act 240 r.pjn.. which it ver> low. the car would maLe 


10.3 m.p.h. as its lowest possible speed. And at 240() r.p.m, — a higli 
maximuni for an engine with as low a speed aa 240—the highest cur 
speed would be 103 m.p.h. As the average roads would not allow this 
high a speed, and as the average car has a low speed appro.\ioiatin^ 
3 m.p.h., it is apparent that the gear ratio is too high. By lowerine 
this to 12 to 1 at a low speed of 264 r.p.m. of the engine, a low mr 
speed of 2.S5 m.p.h. would be obtained. And with 2ti40 r.p.m. as the 
highest engine speed, the highest car speed would be only 2S.5 m.p-h. 
From these two extremes, It is apparent that direct gearing without 
a transmission is not feasible. 

Q. What are the general classes of transmission now in use? 

A. There are five general classes: sliding gear, individual chitcli. 
planetarj-, frictimi, and miscellaneous tj-pes. The first named is most 
popular and con.'ititutes perhaps 90 or more per cent of all the cars 
now built. The individual clutch is really a modification of the slid- 
ing gear, but is not .widely used — not to exceed 3 or 4 per cent. The 
planetary is the most simple form to operate but, unlike the others, 
is hmited as to the number of possible speeds. Practically the only 
American maker using this today is Ford. The friction form was 
intended to give a maximum number of speeds with maximtun sata- 


A. The operator is at liberty to select any gear he desires and 
to go directly to that speed from the speed which he is using. This 
means with common sense reservations; for instance, it would be 
foolish to go from high to reverse, although this is possible in this 

Q. How is this accomplished? 

A. Within the gear box, the gears are shifted by forms, and the 
quadrant arrangement is such that the driver can shift his lever so as 
to pick up the fork which will give the desired speed. Usually there 
are but two shifting members (in the three-speed form), one giving 
low speed and reverse, the other intermediate and high. Having 
picked up the low and reverse fork, he can shift his lever forward for 
low and backward for reverse; similarly, with the other fork for 
second and third speeds. 

Q. How does the progressive form work? 

A. In this t>T>e of gear box, the speeds must be used in succes- 
sion — first the low, then second, then high, and when slowing down 
from high, to second, then low, then reverse. For instance, if driving 
in high and a turn is passed in a narrow road, it would be necessary 
to shift down to second, then to low, then to reverse. The driver 
could now back his car past the street into a position which would 
enable him to make the turn. Then he could speed up the car again 
by using first low speed, then second, and finally high. This maneu- 
ver could not be accomplished in any other way. In the same cir- 
cumstances with a selective gear, the car could be brought to a dead 
stop with the brakes, an immediate shift to reverse effected, the car 
backed up, and the gears shifted to low and then high speed forward, 
thus doing the same thing as before with half as many changes. 

Q. How is the high speed generally effected? 

A. High speed in all modem transmissions is a direct drive so 
that none of the various gear reductions are in use. This method 
reduces the amount of noise by eliminating at once the meshing of 
two sets of gears, the average high-speed direct drive being effected 
by clutching one gear up to another. 

Q. Is this arraiq;ement always used? 

A. No. In some four-speed gears the highest speed is a geared- 
up form, and the direct drive is used on third speed. This is done with 
the idea of securing the silence of the direct drive for all averafi^ 


rapid driving, wliile the geared-up form gWcs an extraordinary spee<i 
for emergen cies where imise is iniinateritii. 

Q. In the electric gear shifter, how is the movement of gears 

A. The shifter is ninde with a series of electromagnets, or sole- 
noids, one for each speed and one for reverse. Current flows to these 
when the proper biittun is pressed. It is well known that when an 
electric current is passed through an electromagnet of the solenoid 
type, the rod, or bar, inside of it is drawn forward. This arrangement 
produces the speed corresponding to the button pressed. In actual 
practice, the current docs not flow until the clutch pedal is depressed 
after the button iuis bwn pressed. 

Q. Where is the transmission located? 

A. Excluding freak forms, there are four general positions: in 
unit with the motor; amidships in unit with the clutch; amidships 
but separated from the clutch and in unit with the forward end of tlie 
tiriviug shaft; ami in unit with the rear axle. 

Q. Are these same locations used on motor trucks? 

A. Yes. Except tliat the third class is sometimes modified with 
chain i!ri\e. sn ihat the transmission is amidships but in unit with 


a gear on s shaft to which it is keyed, moves a clutch which keys the 
desired gear to the shaft. 

Q. What is the advantage of this over sliding gears? 

A. In the sliding gear, the moving members must take the drive 
and transmit the power in addition to withstanding the-shocks and 
destructive action of shifting or meshing. In the individual clutch 
form, the gears have only to transmit the power, whjle the individual 
clutches have ojtiy the shocks and destructive action of shifting. 

Q. How are gears pressed onto their shafts? 

A. Usually by means of a hydraulic or a power press — one 
capable of exerting a pressure of many tons. Generally, it is easier 
to lay the gear out on the press table and press the shaft down into 
it, than the reverse. 

Q. How are pressed-on gears removed? 

A. The process of pressing on is reversed, and the gear is sup- 
ported in such a way that the shaft can be pressed, or forced, out of it. 

Q. How is the transmission removed from the chassis? 

A. The usual method in well-equipped shops is to put a rope 
or chain sling or special cradle around the transmission, then to lift 
it vertically upwards by means of a block and tackle, electric or pneu- 
matic overhead hoist, chain block attached to overhead tracks, or 
portable crane. 

Q. How are bearings worked in? 

A. After slow careful fitting by hand for both diameter and 
length, using a dummy shaft with dummy bearings, the real bearings 
should be put in place and run-in for several hours, using power from 
a line shaft. Transmission bearings should be run-in the same as 
engine bearings, set up somewhat tight and with an excess of oil. 
Questions for Home Study 

1. Describe the construction of the Cadillac and Winton trans- 
missions, a railway transmission, the Mack truck, the Ford planetary, 
a friction form, and a magnetic type. 

2. How would you adjust the shafts longitudinally in the 
Steams transmission? 

3. Tell how to construct a stand for gear pressing. 

4. Give a thorough method of cleaning a transmission. 

5. What are the usual gear pitches? 

6. What is meant by the pitch of a gear? 




The mechanisms by which steering is effected are among the 
most important features of a car, if not actually the most important. 
The truth of this statement will be realized when attention is called 
to the fact that safe steering is the final requisite that has made the 
modern high speeds possible, t6f without safe and dej)endable steering 
gears, no racing driver would dare to run a machine at a high rate of 
speed, knowing that at any minute the unsafe steering apparatus 
might shift the control, thus allowing the front wheels to waver and 
the car to run into some obstruction by the roadside. 

The same argument applies in an even greater degree to the 
case of the non-professional driver, who wants to be on the safe side 
even more, perhaps, than do the dare-devils who drive racing cars. 
Neariy all of our roads are curved and, to make all of these turns 
with safety, the steering gear must be reliable. Again, in mountain- 
ous country where there may be a sheer drop at the roadside of 
hundreds of feet, it becomes necessary that the steering mechanism 
be very acciuute aftd that it obey, at once, the slightest move 
on the driver's part. To secure this accuracy, there must be no lost 
motion or wear of the interrelated parts: 

These things mean that the whole steering mechanism must be 
safe and reliable; strong and acciurate; well made and carefully fitted; 
well cared for; and finally, the design and construction must be 
based on a theoretically correct principle, for otherwise the mechanical 
refinements will have been wasted. Perhaps it will be more logical 
to treat the mechanical requirements first by showing how the 
present tj^ has been evolved from the failures of earlier forms. 


General Requirements. In turning a comer a car follows a 
curve, the outer wheeb obviously following curves of longer radius 
than do the inner wheeb and, therefore, traveling farther. In 


straight-ahead running, the wheels run parallel at all times and 
travel the same distance. These two faets are the basic ones which 
make the steering attitm so complicated: First, that on straight- 
ahead running the wheels must travel the same distance; and second, 
that on turninp curves the outer wheels, whichever they may be, 
must travel a greater distance. 

This double requirement leads to the usual form of steering 
arrangement, called after its inventor, the "Ackerman". It was 
Ackerman who brought out the first vehicle in which the front 
wheels were mounted u[xni pivoted-axle ends, these ends being pivoted 
on tlie extremities of the central part of a fixed axle, while the pivoted 
ends carried nnc lever each. These levers were connected together 
by means of a cross-rod, while at one end another rod was attached, 
which was used to move the wheels. By moving this latter rod, 
Inith wheels were compelled to turn about their pivot points, since 
the cross-rod joined them together, and if one moved the other had 
to move also. Tliis was Ackerman's substitute for the fifth wheel 
which had been used up to that time and is even to<lay on all horse- 



pivot, which is liable to wear, inaccessible, it also was ab&ndoDed. 
However, later tendencies point toward a revival of this constnictioii. 
The result is that today we are using a form which, though far 
from being ideal, fulfills every practical requirement. This form is 
usually constructed as in Fig. 316, which shows a skeleton plan view 
of an automobile. In this, the line AB represents in length, posi- 
tion, and direction, the front axle of a car, while ML represents 
in a similar manner the rear axle. A and B also are the pivot points 
for the axle-stud ends or, as they are more commonly called, the 


Fif. 3ie. Diacrun of Steering 

steering knuckles or steering pivots, which are represented by the 
lines AB and BC. 

The rear (or front, as the case may be) ends of the steering 
knuckles are joined by the connecting rod DC The Ackerman con- 
struction is such that the center lines of the steering arms, or levers, 
AB and BC, prolonged, must pass through the center point of the 
rear axle at K; the reason for this is that the front wheels are sup- 
posed to turn about the center of the rear axle as a center. 

Action of Wheels In Turning. If the wheels are supposed to 
turn through an angle, the action of the above arrangement will be 
seen. Suppose the steering gear (not shown in Fig. 316) is turned so 
as to move the steering lever AB to the new position, shown dotted 
at AI>\. Thb movement will also move the other lever BC to a new 
position, shown dotted at BC\. It will be noted in this position that 
the angle through which the right-hand lever BQ has swung ia notAa 


great as that through which the left-hand lever AD has moved, 
although the twu levcra are attached together by means of the cross- 
connection DC. 

The wlieels arv mounted upon the extreniities of the steering 
knuckles at /' and /; EG represents the left wheel, and HJ the 
right wheel. These turn about the pivot points A and B, with 
the movement of the steering knuckles to the new positions, shown 
dotted at /si/'[G[and lIiIiJi. In this position, prolongations 
of the lines through the pivot point and the center of the two 
wheels will meet the rear-axle center line prolonged at separate 
points as 01', the two lines converging slightly. This same con- 
vergence may be noted by prolonging the center line of the two 
wheels EiGi to Q and IltJi to R. This divergence means that 
the two wheels are turning on curves of different radii, and since the 
outer wheel 11 iJ \ sliows a longer distance from its center line pro- 
longed to the rear-ax!e line 0PM KL than does the inner wheel, 
that is, has the longer false radius, PIi being longer than Of i, it 
follows that the turning action will be correct. 

This is siiniewhiit complicated and rather hard to follow, but 
the figure secmH simple and should be examined closely, even draw- 



known as the Davis, the steering levers are set in front, but taper 
inward instead of outward, so that their center lines prolonged 
meet the center line of the car prolonged at a distance from the front 
axle equal to the distance between the front and rear axles, or equal 
to the wheel base. 

In addition, the connecting rod is carried in guides placed on 
the front of the axle, so that its path of travel is always parallel to 
the front axle. Consequently, the levers must be made slotted or 
telescopic. The result of this combination of movements is an 

Fie. 317. Pfttented Enfjaah Stoerins Derke. SiUd to b« Tht^jnthtmUy P«rf«fi 

absolutely correct angle to both wheels for any angle ipf kxdc. Thin 
can be explained by a reference to the diagram* 

In Fig. 316 the prolongations of the wheel center Vtnen, r/r rarli i rif 
turning, do not strike the center line of the rear axle — abcmt whicrh 
they are supposed to turn — at a common pointy the difference being 
the amount they are out of true, viz, the distance between the priintn 
and P. If Fig. 317 be lettered to correspond with Fig. 315, the 
im>longatioDs of the knuckle center fines AP/f and IiBF in 
fig. 316 beoome the two c on v e rgi n g fines AF/J and t\BO UMt^t^^ 



at the poiut on the center line LMO of the rear axle prolonged. 
This is as it should be and shows the case of correct steering and 

In this case, all four wheels are turning about the point 0, the 
two rear wheels with the radii OM and OL, and the two front wheels 
with the radii OFi and (fl,, respectively. This gives a theoretically 
correct case in whiih all wheels will round any curve as they should 
and not slip or slide around, damaging the tires in the process. The 
Davis ty[>e of steering gear, it may be remarked, is not in general 
use, its cohstruction adding a number of parts to the more usual form, 
shown in Fig. 31H, which gives close enough results for average use. 

Like the sliding-gear transmission, a steering gear is a form of 
mechanism which, although used on nearly all automobiles, is, from 
a thettretical and mechanical standpoint, far from what it should be. 

General Characteristics of Steering Gears. Standard Typea. 
The movement or deflection of the front road wheels is obtained by 



through a fairly large arc, according to the capacity and design of 
the steering gear. 

As the ball arm swings through its arc, the drag link attached to 
it rises and falls slightly, the movement being indicated by the dotted 
lines in Fig. 318. The partial circular motion in a vertical plane ia ' 
converted from the rotation of the steering gear in a horizontal plane 
by several methods. The gear shown in Fig. 319 is known aa the 
worm and sector type, which is illustrated in Fig. 318. 

In Fig. 319 the steering column or post CD carries a worm F 
which is in mesh with the gear E. 
Rotating the column CD in the 
direction indicated by the arrows, 
or counter-clockwise, will result 
in the worm turning in the same 
direction. The gear E will rotate 
on its horizontal shaft in a down- 
ward movement, as shown by the 
arrow, and as the ball arm, or 
lever, is attached to the shaft, the 
member L will move backward, 
or to the left, as shown by the 
arrow intersecting the ball. With 
the worm type the two gears are 
usually in two different planes 
at right angles to each other, one 
vertical and the other horizontal. 
This is an advantage in that it 
lends itself readily to the con- 
stnictioQ of a simple steering- 
gear system. Thus the post ia in a vertical or modified vertical line, 
as is also tiie motion of the steering arm, and the consequent 
movement of the steering rod is more or less confined to'a vertical 
plane. With the worm and gear thb is obtained in a simple manner. 
The gearshaft is in a horizontal plane passing through the center line 
of the worm. If the worm„ rotates in a direction which approxi- 
mates a horizontal circle around a vertical axis, the worm gear will 
turn in a vertical plane about a horizontal axis. A lever attached 
to the end (rf this shaft will, consequently, move ia the denind. 



plane — the vertical one mentioned before — and the desired requii*- 
ments are met. 

The conversion of rotary motion in a horizontal plane to partial 
rotation in a vertical plane is shown in Fig. ^20, the action here being 
slightly amplified. The steering, or hand, wheel .1 with spokes B is 
turned to the left, turning the steering coluttin C (a hollow tul>e) in 
the direction indicated by the small arrow. I) is the steering gear 
with its ball arm E. The turning of the hand wheel moves the 
ball end F and drag link backward. The front end of the drag link 
is attached to the steering knuckle M at // and turns about the 
center line KL of the steering knuckle ./, the end turning through 


M.t M 



the road wheels any turning movement imparted by the driver 
without reveraing or carrj-tng back to the operator the original move* 
ment of the road wheels. 

Many attempts have been made to substitute another form of 
mechanism for steering gears; this consists of various rod, lever, 
chain, and spring combinations. All of these have failed, lioweveTt 
because they lacked the 
fundamental reauisite of 

Aside from the many 
schemes mentioned which 
seek to avoid the use of 
the regular gear in the 
standard manner, there 
have been a number of 
unsuccessful attempts to 
avoid its use in other 
ways. Fig, 321 shows 
some of the gears which 
have been tried. At / b 
seen a device in which the 
rotation of a' Urge bevel 
gear turned a smaii bevel 
pinion, the rotation of the 
latter ser\'iiig to screw a 
long straight lever with a 
threaded inner end into or 
out of the interior of the 
threaded be\-d jnaion. 

In the figure. .V is the 
actuating bevd turattl by 
the movement ol the opcnfjr'i iias^t, while in it^ xftniUr Mto* 
ated be^'d {ndkiD. Vi'itbin tii'a u «*ri ti^. wim> rt^\ H 'A the 
lever J, the ball at tke outer oA \^t>^ mta^'^tfh Ut 'ij^t 'Mtmnn 
knudtle. Since tbe berd afrwft ]f/vt a 3^*a% d/^al td ^/»*t 'tt, Irft^X; 
while the vonn armtgtwect aivi the ^'wiin^ lu^/t. '4 ^'t^. '^rtn in 
its bearii^s did Ekewue, tiw xmaX tMim. Ut torn t>.ut nuvtt nanf. i>w» 
enomioas. At 2 b dwwn urxiier fona, ■m^Jt^ i^ the ^fJtMtAmnd 


arrangement; a small bevel N attached to the steering post A' turns 
the larger bevel 0, which is pivoted at the axis M about which the 
lever J attached to the segmental bevel tiu-ns. 

A most peculiar arrangement is shown at .?, this being a com- 
bination of a worm and nut, two levers and a steering arm, as well 
as a connecting link for the two levers. Turning the hand wheel 
turns the worm, which moves the nut up or down. Since the nut 
is connected by means of the link to the lever, the motion of tlie 
nut up and down is transmitted to the short lever; this, in turn, 
moves the long-arm, or steering, lever. In the figure, A' is the steering 
post. A' the worm, the nut, P the connecting link pivoted at the 
two ends T and S, Q the short-arm lever, and J the steering lever, 
the two latter being integral and pivoted at the point R. At 4 
is shown a combination of a double internal wonn with a rack and 
gear. In this, the turning movement of the inner worm causes tiie 
outer worm to travel up and down, l-'pon the exterior of this outer 
worm is cut a rack which is meshed with the gear, its up and down 
movements turning the gear around and thus effecting the steering, 
the steering lever being attached to the gear. N is the iaterntJ 
worm, the external worm with the exterior rack, P the gear which'J 



and parallel with the axis of the shaft on which the gear turns. In 
bevel gears the teeth taper toward a point and are inclined to the 
axis of the shaft. Another construction is the spiral gear. Both 
types may be made reversible and irreversible as desired. 

Womi-Qear Types. With a very few exceptions, automobile 
engineers favor the worm tj-pe of steering gear, and it will be found 
on the highest priced cars. It has the advantage of being irreversible 
and b utilized in several forms. In the worm class of gears, some tj'pes 
are closely related, while others varj- widely. For example, the com- 
plete sector and gear tjpe 
differ only in that the wheel 
operated by the worm makes 
a complete circle or part of 
a circle. The full gear can 
be turned through 90 degrees 
and replaced on the shaft 
without presenting a new 
surface to the worm. Some 
hold that the worm must be 
subject to some wear, espe- 
cially where it b most used. 
They contend that turning 
over the pinion brings new 
teeth to engage with the 
worm and that these teeth 
ivill not mesh properly when 
turned at an angle of from 
20 to ."iO degrees. 

Worm and Pariial Gear. 
Fig. 322 illustrates a gear of the worm and partial gear type. 
Advantages claimed for the design are durability, ease of action, 
and adjustability to wear. The parts are accurately cut and hard- 
ened, and the worm is provided with a ball thrust on either side. 
With this type, the teeth, which are in the middle of the sector 
and in mesh, perform the greatest work when the car is driven in 
a straight line and are most susceptible to wear. To compensate 
for this wear, the center teeth are cut on a slightly less pitch radius 
so that lost motion may be eliminated without affecting the upper 

fit. 322. WoTi 


and lower teeth of the sector and to prevent binding when turoiii^ 
at right angles. In the Illustration, A is the steering column to 
which the worm f is secured, D is the sector in mesh «-ith the 
worm, E is the ball arm, or lever, B the gear housing, F the spark 
and throttle bevel gears and levers, and G the lubricant plug. 

Adjustment. Two principal adjuBtmenta are provided. End 
play of the worm is eliminated by lw>s(ming the jamb nuts and lock 
screws on the column housing. Displacing the oil plug will dis- 
close an adjusting collar which is set with a screwdriver. Adjust 
collar until all play is eliminated, but the worm must turn easily. 
The lock screws, above referred to. are so located in the gear hou.«ing 
that when one is directly over a slot in tlie arljuittiiig cuilur the other 
is between two slots, fonsequently, after adjusting the collar it is 
essential that the proper screw be selected for locking the adjustment. 
Both locking members he prevented from turning, by using the 
nuts. Wear of the teeth of the worm and sector may Ite eliminated 
by means of an eceentric bushing, which, when turned, moves tlie 
sector into a closer relation with the worm. Tins is accomplished by 
removing a locking screw at the left of the hall arm. and moving 
the arm, which turns the eccentric buiihing. In case of extreme wvaTj 

\t mnv hp nPf«=carv tn (lionloo* fhn lioll »-m «n,l «.>t .I.b I™ 



be attached to but one of the turning gears, the other gear with 
its actuating worm 13 useless. The inventor doubtless intended 
the two worms to oppose each other and thus be self-sustaining as 
to thrust, but such would n^t he the case, the actual thrust being in 
opposite directions in the two cases of the upper and lower worms, 
the total thus being double the usual amount. 

Adjustment. The part most subject to wear is that section of 
the gear which meshes with the worm when the front wheels are 
traveling in approximately a straight line. Because of this wear, the 
teeth of the wheel are subject to deterioration. Usually the adjust- 

Fia. 323. Typical Wotin tad Full Gear Stntioc Deviw 

ment for the wear is made by bringing the worm into a closer relation- 
ship with the gear by using the eccentric bushings which support the 
worm shaft. This adjustment b practical when the lost motion is 
due to poor adjustment rather than to wear of the teeth. With the 
majority of tj'pes, it is possible to displace the steering arms, move 
the steering wheel about half a turn, then replace the worm wheel so 
that an unworn section opposite the worn teeth will be brought into 
engagement with a comparatively unwom portion of the worm 
proper. The eccentric busings in this case can be utilized to obtain 
a correct meshing of the worm and gear teeth. End play of the wonn 


tan he rfmnvt'ii hy adjusting the ball thrust bearings on either side 
of the wiirni. Sninftimes these bearings become dry, or the lubri- 
cant becomes gummy, causing the shaft to turn hard. Wear of plain 
bushings in the steering-gear case is responsible for lost motion; the 
remedy is to replai* the bushings with new members. 

Worm and Siit. Next to the worm and gear, either full or 
partial, the form of steering gear most used is the worm and nut, 
which is made in sevenil different combinations. Thus, the nut may 
operate the steering lever directly through the medium of a secondary 
lever, or it may actuiite a block, which, in turn, moves either the 
lever direc-t nr the sfnindary lever. In Fig. 325 another form of 


Having the nut in two widely separated parts reduces the wear 
on each, since the bearing surface is spread out more than would be 

Fi|. 3M. SUntaw Gtmt U»Bd on H«vy MiubsCUn Truclu 

the case with an uncut nut. In addition, the split nut allows the 
changing of the ball-end lever at any and all times. 


In Fig. 326 is shown a form ol 
wonn and nut steering gear which is 
used on very heavy trucks and com* 
mcrical cars. In this gear, the double 
worm is u-sefl ; the inner worm cnrries, 
at its lower end, a block which is piv- 
oted ill a combination lever and shnft. 
to which the steering arm is attached, 
In the figure, A is the hand wheel 
turning the rod It within the steering- 
post tube ('. This nxl is driven into 
and keyed Ht its lower end to a mem- 
ber D which has internal worm 
threads. Another niemlK-r E has a 
circular upper end on which are worm 
threads, while its lower end is slotted, ■ 
Tlie worm at the npper end mesbes 
with the hiternal worm threads in 
piece D, while the lower slotted end 
carries, between the two arms of the 



extension of the shaft, must tiun the shaft. To this arm is attached 
the steering lever, so the latter must move. Although a rather com- 
plicated gear to explain and also to make, this gear, when finished, is 
an excellent one, and has been used for five or six years on heavy 
trucks with excellent results. 

The Winton steering gear. Fig. 327, is not decidedly different 
from the one just shown, as will be noted by a close inspection of the 
parts. A is the internal worm, which is turned by the hand wheel, 
while engaging this worm are the block B and pin C, the block being 
partly cut away to show the engaging gear teeth. This block moves 
the jaw arm of the steering lever D. This jaw is not complete in 
this gear, but is cut away to save weight. The jaw arm, too, is con- 
nected directly with the steering lever, the jaw, arm, and shaft making 
one piece. The light work to which this was put made possible the 
economy in the number of pieces and in the weight of each. As 
before, turning the hand wheel turns the worm, which, in turn, moves 
the block and pin up and down and thus moves the jaw arm, which 
moves the steering lever. 

Adjustment. The adjustment for lost motion in the worm and 
split-nut type of gear is generally made by loosening a cap screw on 
the column and screwing down an adjusting nut which has a right- 
hand thread. This adjusting nut acts directly on- the thrust bearing, 
forcing the screw and half nuts, which slide, against the yoke rollers. 
In making the adjustment to a gear of this type, it is advisable to 
turn the road wheels to the extreme angle position, because the gear 
is the least worn at this point, and if it is adjusted only enough to 
take up the play when in this position, there will be danger of binding. 
Sometimes, when the adjustment is made with the road wheels straight, 
the gear will bind at the extreme positions. 

Worm and Worm. In the worm and worm form of steering gear 
there is ia worm within a worm, not wholly unlike the ones just 
described. Fig. 328 shows an example of this, which has a worm C 
attached to the steering rod H, which is turned by the steering wheel 
A. Within and without this are worm threads, an externarworm 
B meshing with the internal worm on the inside of C, while an internal 
worm D meshes with the external worm on C The action of turn- 
ing the hand wheel, then, moves one of these up^axA «bxA XJoa ^"Oc^t 
J ] 


The lower end Bi of the inner worm member presses Hgaimt 
a hardened end of the steering-lever arm E, while the lower end /J. 
of the outer worm member presses against the other hardened emi 
El of the same piece. There is no lost motion, or play, in the gear; 
when the hand wheel is turned, one worm rises and the other falls, 
as just described; the piece E will let one end rise and the other fall, 
as it is acted upon by the lower extremities of tlie two moving worms. 
This piece is pivoted at F and carries at Its outer end the steeriiiff 
lever G, which thus moves in the customary manner. WitbJn the 
steering post arc the spark and throttle tube and rod / and J, which 


bevel pinioD moves the bevel-gear sector back and forth as it b turned, 
this motion being transferred to the steering arm attached on the 
same shaft to which the bevel sector is secured. This type of gear is 
said to be effective, but it is not irreversible, and shocks to the road 
wheels may be imparted to the steering wheel and move it. 

Adjustment. The bevel and sector gear haa two adjusbDnats. 
The pinion may be moved up or down, as required, by unlocking the 
clamp bolts (one of which is shown at D) which pwm\\s\)aft TawVi^^A 
the entire ^te^g co/«qiq yp or dgira w «a \ft QV^^aJ©.^ 'giw^R^ 



relative position to the pinion and its sector. The position of the 
sector endwise may be adjusted by the block member A, which bean 
against a roller guide, forcing the sector into meah more or less closely 
with the pinion. The spring E is provided to prevent rattling, and 
the screw // is a guide for the plunger and should not be disturbed 
in making the adjustment. 

Hindley Worm Gear. Tliere are a number of things aWut the 
Hindley type of worm which make it an excellent one to use for 
steering gears. A realization of this advantage is bringing about a 
greatly increased use of this form; so it will be appropriate and timely 
to look into it.s form, i-oii- 
structioii, and advantiigca. 

The question of what 
makes the Hindley different 
from other worms naturally 
arist<6. The ordinary womi 
has the same diameter from 
one end to the other, the 
blank before the cutting o{ 
the teeth resembling a se»^ 



This fonn of worm is used for the double reason of presenting 
more wearing surface — since it has at least three teeth in contact 
at any one time, as compared with one or at most two in the 
ordinary worm^— and greater resistance to reversibility. The worm 
is used for steering gears because it is partly or wholly irreversible, 
its motion being a sliding one; nevertheless, all worms may be 
so cut as to be either wholly or not at all reversible. The sliding 
motion of the two parts in contact, as opposed to the rolling motion 
in the case of other mechanical movements of a similar nature, is 
greatly increased if there are three teeth in contact instead of the 
more usual one. If the friction of sliding be increased, the amount 
of reversibility will be decreased in the same proportion, for the added 
sliding friction will increase the natural reluctance of the worm to 
transmit power backwards. So much is this the case that it pays 
to use the Hindley form, despite its greatly increased cost of cutting. 

Ford Steering Gear. The steering mechanism of the Ford car — 
a patented construction — differs radically from the conventional 
types in that its hand wheel does not directly rotate, or turn, the steer- 
ing column or rod, but it imparts the necessary turning movement 
through the gearing and the use of a small shaft to which the hand 
wheel is attached. A phantom view of the gearing is shown in Fig. 331 . 

The steering column with its short shaft and drive pinion is 
enclosed in a tube or housing which is set at an angle and bolted to 
the dash. The housing does not extend the entire length of the 
column, as the lower end of it is mounted in a bracket that is rigidly 
bolted to the frame. The steering-gear post, or column, has a tri- 
angular flange at right angles to the rod, and each point of the flange 
has an integral stub, or pin, carrying a small spur pinion. The center 
of the rod is drilled and bushed to take a small shaft to which a fourth 
pinion, or drive pinion, is keyed. The upper part of the housing is 
shaped so as to provide a gear case, and the inner periphery of this 
case is cut to obtain spur teeth or, in other words, an internal ring 
gear. This gear is stationary. 

The hand wheel is attached to the short shaft, and its drive 
pinion is held in place by a brass cover of the internal gear case. As 
the drive pinion of the shaft is in mesh with the three pinions mounted 
on the stubs of the steering column proper, and these iVvxee -^VK^s^jka* 
are in mesh with the internal ring gear, any movemexvt o\ \>aRi VwA 



wheel will rotate the drive pinion on its shaft. This movement will 
cause the three spur pinions to rotate in an opposite direction against 
the internal gear, thus reducing the movement of the steering column 
as compared to that of the hand wheel. The three spur pimoiu 
compensate for any pressure of the drag link and the tie rod. 

The operation of the Ford steering-gear mechanism explains the 
basic principle of the operation of the hand wheel; that is why the 
wheel is turned iii the same direction that the driver desires the car to 



Tbe drag link of the Ford steering gear differs from conventional 
designs in that it is at right angles to the frame and is practically 
two-thitds the length of the tie rod. The end of the steering column 
is provided with an arm carrying a ball, and the drag link, or steering- 
gear connecting rod, as it is listed by Ford, has a ball-socket 
cap which fits over the ball of the steering rod. Tbe drag link also 
has a ball socket at its other end, which fits over a ball arm on the tie 
rod. The tie rod, called the spindle connecting rod because it con- 
nects the spindles, is provided with 'yokes at either end, and these 
yokes are pivotally connected to the spindles by a bolt passing 
through them and 
through an eye in the 
spindle. The Ford drag 
link differs from others 
in usual practice in that 
it moves to the right and 
left, white those used on 
other cars move forward 
and backward. No pro- 
vision is made with tbe 
Ford drag link for absorb- 
ing shocks or for auto- 
matically compensating 
for wear as usually is the 
case with the conven- 
tional type of drag link. 

Semi-Reversible Qear. The steering gear used on commercial 
cars, particularly trucks ranging from 3- to 7-ton capacity, must not 
only be capable of operation with a minimum effort, but it must 
absorb a great many of the minor shocks and a per cent of the larger 
shocks. The semi-irreversible tj'pe is most favored because of the 
above-named reasons. The design shown in Fig. 382 is of the screw 
and nut type. The nut is a solid piece, completely enveloping the 
screw, and the threads of the screw are in constant and complete 
engagement with the threads in the nut. The screw lias a rotary 
motion and the nut has a longitudinal motion. The means of trans- 
mitting this longitudinal motion of the nut to t\ie tq\».t5 TonfCxwi. *A 
the steen'ng arm is by circular discs at the \oweT eai cS. \3Re. wmX. 

Us. 332. Screw u 

I Nut Omf U»d on TruHo 


These discs present constant bearing surfares to the recesses in Uw 
nut, and are provided with slots into which the projecting levers from 
the rocker shaft fit. The screw pulls the nut up or down in the 
housing, and there is nti tendency /or this nut to be moved sideways. 

Hdji^ting tlut B 


in Fig. 333, which is a semi-irreversible wonn and gear, the removal 
may be accomplished by displacing the control levers at the top of 
the column and dropping the unit down through the frame. The 
adjustment of this type for end play is made by loosening the locking 
nut A and turning down the nut B until the play is eliminated. 


Lost Motion and Backlash. Lost motion of the steering wheel 
does not always indicate that the steering gear is at fault, for wear in 
the steering-gear assembly usually takes place first in the clevis pins, 
yokes, and connections of the drag link. The spindles, spindle bolts, 
and wheel bearings are factors. Despite the fact that the front road 
wheels are deflected but a few degrees the spindles, bolts, or bushings 
may be worn, as these parts are subject to radial and thrust loads. 
The spindle bolt, which does not move, tends to wear oval; adding to 
this tendency the wear of the spindle bushings, one has considerable 
lost motion to contend with. Wear of the wheel bearings contributes 
to the apparent lost motion of the steering gear as do the connections 
of the drag link. Taking all of these factors into consideration, and 
allowing but a small fraction of an inch for play of each worn part, 
the sum total may result in considerable movement of the hand wheel 
before the road wheels are deflected. 

Lost Motion in WheeL While there should be a certain amount 
of movement to the hand wheel before it actuates the road wheels, 
the lost motion, as a rule, does not exceed J or f inch when the gear 
is new. This amount is essential as without some free movement the 
steering of the vehicle would be tiresome. Wheels may be keyed or 
pinned to the column. When play exists as the result of a worn key, 
pin, or slots, the remedy is to re-cut the seats and make and fit a new 
key or pin. With some types of wheels the use of a wheel puller will 
be necessary to displace them. Another cause of lost motion, when 
the wheel is tight and linkage free from play, is a loose key retaining the 
worm or gears of the steering gear proper. A simple test of the hand 
wheel is to hold the tube, or post, securely and move the hand wheel. 
The amount of play in the drag link can be ascertained by grasping 
it about midway and trying to move it backward or forward or in the 
normal direction of travel. Hold the. ball arm of the steering ^^^ 
when making ibis test. 



The amount of backlash present in the irreversible and semi- 
irreversible types of steering gears may be determinefl by disconnect- 
ing the drag link, grasping the ball arm, and moving it up and down 
and back and forth. Worn bushings in the steering-gear case are 
frequently the cause of movement of the column as a whole. Another 
component that should not be overlooked in the search for the cause 
of lost motion is the ball arm. Movement of this member on its 
sliaft can usually Ix' eliminated by tightening the nut. 

Different Forms of Hand Wheels. IVood Rim. 'A variety of 
material is utilized in the construction of the wheel, which has super- 


indicates the wood monb^, B the arms> or spokes, which have a 
boss through which the screw C passes into the wood. The hub of 
the spider D is attached to the steering post by two keys E, 

Metal Core with Wood Covering. When the wheel design is made 
up of a metal core the ring is cast on the spider or integral with it. 
Coverings of wood concealing the ring are useil, although with some 
types, a section of the ring may be noted. This type of wheel pos- 
sesses great strength and the wood veneers can be secured at more 
frequent intervals than in the design previously described. 

Different Wheels for Commercial Use, Truck Types, For the 
light delivery wagon, taxicab, and similar cars, no difference in the 
steering wheel is made, but when it comes to the heavier service, there 
is a need for a heavier wheel. This does not mean a heavier rim 
only, but a heavier, more rugged gear all the way through. The 
weight on the front wheels of a heavy truck is very great, and 
the tires, which are of solid rubber, may have frictional contact with 
the pavement of several inches in width. All this combines to make 
turning the vehicle from the driver's seat more difficult. 

For this reason the driver must have a greater leverage, wtiich 
means a larger diameter of the wheel. Then, too, the rim should be 
bigger in section in order to withstand the harder use of commercial 
service, and to provide for the large hands of the operators. Greater 
strain upon the rim of the wheel, on attempting to turn heavier 
weights with it, means that the rim must be fastened to the spider more 
securely. This means more arms, the four generally u«e<l for pleasure 
cars being increased to five for trucks. While this helps a great 
deal, since it provides five screws instead of four, it is not sufficient^ 
and most of the big trucks today are equipped with steering wheels 
in which the rim is built over a central metal rim of the spider. '^ 

Pleagure^^ar Types, Usual pleasure-<!ar practice varies from 
14-inch up to IG-inch wheels, while commercial car sisses begin at 16- 
inch and run up to 18-incfa miieeb on light trucks, and as iiigb as 20- 
and 22-incfa wfaeeb on heavy trucks. Kim sizes vary considerabl.\', a 
favorite for touring cars being an ovsl with from |- to {-inch vertical 
height and a length of about 1 ^ to 1 A inches, l^iese figures Imve no 
connection with oommerdal work* the smallest being 1 inch and on 
up to li inches in faeigfat, with the k^og diameters varying from 1} up 
to If iocfaea. Far qieed work, racing, and the like, it is usual practice 



for tile operator to wind the surface of the wheel with string, thl" 
giving a rough surface upon which the hands wiU not slip. 'Fliis is 
practiced, too, by many truck drivers, who claim that the strains n( 
steering the big vehicle are not felt as much when the wheel is thus 

To preserve llic nice appearance of the steering wheel and rilill 



sions and humps, between which the fingers find a good resting place. 
This gives a good grip, as^e under side of the wheel seldom gets wet. 
Folding Steering Whei(». Although tilting steering wheels were 
introduced several years ago, they did not meet with favor until the 
Cadillac adopted them as standard equipment. The wheel, which is 
18 inches in diameter and has an aluminum spider, is hinged to drop 
downward, a design facilitating entrance and exit at either side of the 
car and making it possible to attain the driver's seat without squeez- 

ing. The Cadillac wheel is shown in Fig. 330, while that used on the 
King car, illustrated in Fig. 337, is of the tilting type. To operate 
the design, the wheel is turned until the wheel spider arm carrying 
the release button is convenient to the thumb of the right hand. 
The button is pushed to the right, and, by using both hands, the 
wheel is pushed forward and upward. The Herff type, shown in 
Fig. 338, is of the true hinged form ; the rim is thrown uv mvA. w*. «A. 
thewa^, thatis, tberim oaly, as the quadrant ca,tT>•«v^^^3BftS^■^*'^ 



throttle levers remains. There are several other tj-pes marketed, but 
their working principles are similar. 

Throttle and Spark Levers. In the usual case, the arms o( 
the steering wheel have the 
quadrant fur tlie spark Hn<I throt- 
tle levers fastened to them. The 
le\'ers are operated within the 
space inside of the rim of wooil 
nnd above the spider of metal: 
the latter is usually' at a lower 
level by several inches, as shown 
in the figure. In Fig. 334, how- 
ever, the quadrant is not carried 
by the spider arms, but on a sep- 
arate framework 0, or spider of 
its own. up above the hub of the 
wheel. Over this frame- 
work the spark and throt- 
tle levers // and / work, 
serrations of teeth in the 
niiadrant nrnvRntins 



jecting doim fron k C, wk3t dr surtsLt: rod v&ack aMants tkt 
lower end of dip ai^ nfc Ae Icnr m dir tiBHftL' k mmIhI AR. 
F is the lcnw*L' pinttd b tfe axle, -wiath anits tkr tw^wl Imr 
E, one ann of vUcfa ba$ the gwria^ rod anadvd to h at A. wtfr 
the otbo' cairies thr m si ^ aoaa t to^ rod jociiD^ thr t«\> kaacUe^ 
together. Since tfar pnxx point k fimL aur momtct n^wml n^ 
the knuckle must icsoh in as i w in g in g aboot the psrM {iwait and 

j carrj'iiig the vliccls vitli it. 

, This moi-cment b impuied by die ftraiu: tvd to lix «ai B 

■• ' of the arm E. Tbr stcrtiiic rod itself ^mplr 

I <roiuiects with the steoing fevef C, sTinpjij 

< back and forth in a vrrtkal pUne with the 

i steering knuckle F. ■wioA sntgs aroond sod 

t hack in a bonxbotal piaac, and imparts (br 
movement erf the ie\^ to the knitckle. Since 
the end of the aeeriog Ic^tr nse« and falb and 
the end of the lever on the knuckle mainiaina 

a constant Ie\-el, altbou^ monng in a cirde, the ml must haw a 
universal joint at one end. This b really a necessity fiwu tww p^tints 
of view: to allow the rear end to move up and down verticallj- whilv 
the front end swings around in a circle; and also to allow the fn>nt 
end to swing in a circle set in one horizontal plane, while the rear «mI 
remains stationary- or practically so in that plane. In short, tlte twtt 
ends move continuously, each in its own plane, but the twtt 
planes never coincide — the one is alwaj-s vertical, while the othor 
always stays horizontal. Thia necessitates at least one uniwrmi 
joint. Many ipakers play oa the safe ^de, and loww thec»&t.cX 

. a iiuc on tne outsiae 

itself is made separately am 
shaft, or axis. After this a s 
holds the sleeve up tiglit agaii 
is to give the spherical end t 

Fif. 340. ttlntnng Lover 


side of it. These springs not on 
wear as well, the shoulder again 
In this figure, J is the lower end 
end. This lever is mounted in t 
the steering rod, which is expan' 
this being designated in ♦'•" " 



is disassembled and a longer sleeve inserted in place of the one shown 
at E. On the other hand, ordinary wear is compensated for by 
taking up on the collar C, first loosening the lock screw V. 

In Fig. 342, a rod is shown assembled at the top and disassembled 
into its components at the bottom. The two ends differ, one being 



^^i LJ 

Fig. Ml. Adjiutabfe Form of BaU-End Stwring Rod 

but a simple yoke with a plain bolt through it, marked D. The 
other, however, is a ball end with an adjustment and with springs 
to take up shocks. 

All these parts are marked in the figure and may be located by 
letter. The body of the rod is marked A, the expanded end B, which 
has a groove // cut in it. Into the inner end of this groove is fitted, 
first, the spring F; second, the two halves of the ball socket G; and 


F«. 343. Cnw-Conoectioc Rod AsKmblcd siid In PvU 

third, another spring. The sleeve E closes the outer end, and over 
the exterior is screwed the adjusting nut C. The nut and sleeve are 
held in place by the locking pin V, which passes through the 
outer nut, the shell end of the rod, and the bner spacing sleeve, the 
ends being riveted over to bold it in place. This form limits theadjust- 

the possibility of damage if a 
but in some Instances the tic 


Fis. 343. Finuhod SG.V. Chrome 

K*. 344. Ij'ft Siptfim Knuckle a 

The tip ~-i " ■ 


Function and Shape of Steering Knucldes. The steering knuckles 
serve as a pivot for the road wheels, enabling them to move in a hori- 
zontal plane. The design of the knuckle depends upon the axle, and 
-the pair used on a car are different as one has a lever for carrj'ing the 
drag link. Both have integral spindles to which the tie rod is attached. 
Figs. 343 and 344 illustrate the difference between the knuckles. 

Fi«. 346. Pulurd ElHrinc Geir Parte 

Fig. 343 shows a right knuckle, forged from a blank of chrome nickel 
steel, while the one at its side is the finished part. A is the place 
for the outer wheel bearing, B the position of the inner bearing, C the 
hole for the pivot, or knuckle, pin, D the upturned steering arm, and 
E the arm to which the tie rod is attached. Fig. 344 is an example 
of a left steering knuckle of the same pair, both before and o.fte'c 
machining. The letters in Fig, 343 app\y to ttvra Vaxu^e. 


Lubrication of Steering-Qear Assemblyt Tlie proper lubrication 
of the steering-gear assembly adds to its life, but this work is not, as 
a rule, thorough. The steering gear proper should be packed with 
grease, the ball and socket joints of the drag link and stcering-«nii 
lever with a light grease; the clevis pins also should be lubricated. 
The steering-knuckle pins are provided with either grease or oil cups. 
A point generally overlooked in the lubrication of the steering 
gear is the steering-post spark shaft and throttle-sector anchor tubi-, 
shown in the illustration at Fig. 345, which is of interest in that 
it illustrates the assembly of the Packard car. The post carries 
the control-box unit. The 
spurk shaft and throttle tube 
fn-iiuentlj' lack lubricant and 
slinnld be cleaned and cunUtI 
«itli a graphite grease before 
rt-pliicing when the gear is 
I iciii^ reassembled. The lowxr 
extremity of the spark and 
throttle members carry levtrs 
or small bevel sectors which 
operate the linkage of the mm- 



universal joint to tnuismit uniform angular velocity. Its design was 
brought about by the fact that the rate of transmission of angular 
velocity through a universal joint is not even when the shafts are at 
an angle. This is the fundamental difficulty every designer of a front 
drive has to overcome or suffer the twisting of the axle. 

The front wheels and the flywheel must rotate at practically a 
uniform speed, at least through each revolution. The irregular rate 
of transmission through the universal joint must be taken up aome- 

LaocbUn Pedkl MechAnMra 

where. The normal action of a universal joint at certain angles is 
to make four jerks in a revolution, as it has four fast points and four 
slow points. The Laughlin joint gives uniformity of rotation with 
75 per cent on each side of normal, the difference being taken up by 
the flexibility of the transmission parts. 

Frietiort'Digc Tranamisnon. The transmission is of the friction- 
disc type, but the disadvantage of this form of drive — the fact that 
the control is reversed — is eliminated. The usual clutch control is 
provided, but the pressure is automatic. This pressure is obtained 
by an eccentric cminection by means of which designers obtun. \n«- 



versihle application of spring pressure. The transmiasion locks ttt the 
correct pressure tliniugli the friction of the eccentric. The spring 
controlling the friction for driving proviik-s the pni[)er pressure fur 
running, but it is not sufficient for starting or climbing long hills in 
the low gear. The pedal shaft operates a ilog tluit presses down im 
the eccentric sheave extension. To dc-clutch, the operator presses 
the pedal down, releasing the clutch. The pedal has two points at 
which it latches, providing extra pressure, and an extra spring is 
brought into ser\'ice for the high and low s(>eed. This spring opt^rates 
through a toggle linkage. As the pedal rises, the applied power 
increases. When the car attains momentum, the driver depresses 
the peflal until it latches. The running pressure is sufficient to hold 
the engine in all gears except the low and reverse. 

Control. Complete control is obtained through one gearshaft, 
the lever working forward for progressive, and back for reverse. Auto- 
matic latching is obtained in e\'ery gear, the latch working in sockets 
sunk in the jackshaft. Chain drive is employed between the trans- 
mission and front axle. The brakes are located on the rear axle. 
Fig. .147 shows the method of obtaining a conventional pcdul control 
of the transmission through tlie )rre\'er3ible application of sprii^ 


force is applied to the system, and no matter in what portion the 
wheels may be. 

The advantage of the four-wheel drive and with it the four- 
wheel steer and brake is granted by eminent engineers, as is also its 

Fig. 348. Kde View of ■ Fout-Whwl Drivs, StHr, and Brkke Motor Truck 

necessity for heavy commercial trucks, but its use has not been 
extensive for the simple reason that it is a complicated arrangement 
at best. In many cases, the design has been so complicated and 
unmechanical as to cause failure, and the reports of these troubles have 
given the four-wheel driving, steering, and braking device a sort of 
visionary air, so that any one talking of it is supposed to bea dreamer. 
Such is not necessarily the case, for many different practical four- 
wheel combination driving, steering, and braking devices have been 
brought out, built, tested, and proved efficient. 

A number of four-wheel designs for commercial cars are being 
marketed, and have proved the contention of their makers that they 
are economical in operation and maintenance. 

Four-Wheel Steering Arrangement. With the design shown at 
Fig. 348, steering knuckles are eliminated, the wheeb being con- 

FIc, 346. DetoilB of Aile of the Faui-Wh«l Drive Truck Sbown in Fi«. 348. 

nected to the axle ends through the medium of vertical trunnions. 
These trunnions bear on the wheel ball-bearing ring, which is ample 
in diameter and turns freely because of its size and lV\& Ma& o\ \i^ 



bearings. Within tliis ring, the axle terminates in what is practically 
a universal joint, driving through to the outside of the wheels. The 
wheels are thus free to run about a point in the axle ends, at the same 
time taking their power through the inside rotating shaft. Fig. 349 
illustrates one of these axles with the parts lettered. Here 7/ is the 
point of attachment of the driving propeller shaft, G the cast-steel 
onc'-piete case, F the diflerential gear within the large driven bevel 
gear 0, MM the vertical trunnions upon which the wheels rotate, and 
N N tile univLTsal joints which drive the wheels. 

Hiiw the steering is obtained is shown in Fig. 350. At the front 
of the chassis is the steering wheel P; turning it partially rotates the 
longitudinal shaft Q, which extends the length of the chassis. This 
shaft carries Icvpfs RR near its two ends, which are connected to 

'■ ^fcH^—i ^^ 


distance or time of the ordmary 
truck. Four-wheel steering then 
has the advantage over two- 
wheel, or OTdinary, steering, of 
requiring only one-half the space 
and one-half the time to accom- 
plish a given turn. The vehicle 
described would turn completely 
around in a circle of 40 feet, the 
outermost circle shown in Fig. 
350 being 56 feet in diameter. 

Chain Four-Wheel Drive. 
Fig. 351 clearly illustrates a bot- 
tom view of the Hoadley four- 
wheel drive, four-wheel steer, and 
four-wheel brake truck. The . 
power of the engine is trans- 
mitted through shafts, gears, and 
universal joints to the differen- 
tials; there is a third differential 
in the gear box at the center of 
the frame. Final drive is by 
chain ; both ends of the truck are 
exactly alike in so far as the four- 
wheel drive is concerned, and the 
fifth wheels run in ballbearings. 
Steering is accomplished by means 
of worm gearing, the shaft being 
clearly shown, and both seta of 
wheels are steered simultaneously. 
Jeffery Quad. An example 
. of the successful development of 
the four-wheel drive is the Jeffery 
Quad, Fig. 352, which has given 
an excellent account of itself in 
government work. In this type 
it will be noted that the inclined 
driving shafts, shown in Fig. 348, 

- 6 suuiis TO me ironc a 

tion of each other, are set off to th 
by making the transmistiion verj 
as shown in Fig. 353. Tlie engim 
are gears that transmit the rotatio 
through the final gears E and F, d 

ports, B driving one pair of wheels, 
that the differential has been inc 
so that it is possible to have a di 
from that for the rear wheels. 
Th« r«* "» -' 



section is fixed a small box which contains the bevel gears and an 
additional differential with suitable bearings, the whole being 
enclosed. These can be seen in Fig. 352, that on the rear axle being 

Hlulta tor Roth AiIm 

plainly shown, while the one in front is part1>' obscured. This 
member is shown in detail in Fig. 354, which gives the longitudinal 
section along the driving shaft at the left, in which the axle // is 
noted, the bevel gear /, and the bearings for radial and thrust loads 

F^. 354. Bcdjoi 

Ai]» OD Jcflery Quwl 

at J and A', respectively. The driven shaft is seen at L, with the 
sleeve M around it, the sleeve being used to drive to the difTercntial 
case, since the larger, or driven, bevel C is not suSiewnl\^ Wx%«.\n 
bouse the differentia} /*. 


Fig. 355 is a fiiaf,'rani showing the details of the axle end and 
wlieel constnictifiii. In this, // is the I-beam section of the axle bed 
shoim in Fig. ^52. ami X one of the shafts, which carries at its 
end the universal joint Q, with the end of the shaft extending beyond 
the joint R. Thp latter carries the spur gear S, which mealies with 


turns the wheel is attached at X, the pair (either both front or both 
rear wheels) being connected by means of a cross-rod; at one end of 
this rod there is a connection to a rod which runs the entire length 
of the chassis. This rod is operated by means of the steering gear, 
and imparts the same motion to the front wheels as to the rear, 
except that the two are in opposite directions, that is, front wheels 
turn to the left and rear wheels to the right, so that they will follow 
around in a correct circle. 

Aihardages of Four-Wheel Drwe. It is claimed for the four-wheel 
drive that its four-wheel steering reduces the mileage traveled to the 
minimum in that the car can run closely to corners and travels less in 
crowded traffic, in turning around, and in approaching and leaving 
loading platforms. The push of the rear wheels and pull of the front 
wheels enables it to surmount obstacles instead of bumping over 
them, and its greater traction permits it to travel soft roads not 
easily negotiated by the rear-drive tjpe of trucks and cars. The 
four-wheel drive type will turn in a 48-foot circle, and, with its lock- 
ing differential, obtains traction on slippery roads. 

Electric Drive. When the final drive is electric, or when the 
source of power is an electric motor, the matter of four-wheel driving 
13 much simphfied, the wheel carrying the electric motor attached 
directly to it and turning with it about the knuckle pin. Both 
wheel and motor are turned by means of a worm and gear above, the 
wheel being attached to the upper end of the steering-knuckle pin 
prolonged. Turning thisturns the wheel and motor. 

This steering wheel is turned by the worm, which is on one end 
of a cross-shaft. This shaft is carried in bearings above the stationary 
bed of the axle and has near the center a bevel gear that meshes 
with another bevel, which is, in turn, attached to the lower end of the 
steering post. Turning the steering wheel turns the post and the 
bevel gear, which turns the bevel pinion and with it the worm shaft. 
The shaft turns the worm and the worm wheel which actuates the 
road wheels. The driver thus has a triple reduction between himself 
and the wheels, giving him this much advantage in steering: there is 
the leverage of the wheel of large diameter; the ratio of the sizes of 
the two bevels, and the ratio of reduction of the worm gearing, which, 
in addition, is irreversible. The steering gear is thus eliminated and 
four umple gears substituted for it. 



Coiiple-fimr Ti/pr. In the Couple-Gear wheel, which is an 
American prufiuct, tlie Tiiutor is placed inside of the wheel — a type 
e.spetiall>' designed and construeted for this purpose. With the 
motor in this position, the wires enter through the hollow hub, 
altering its ciinstruction very materially. As compared with the 
electric motor on each wheel, previously described, this form has the 
idvaiitage of greater simplicity, fewer parts, superior appearance, 
and protection against the elements, while the enclosed position of the 
notor, Axhich is the most delicate part of the machine, protects it 
against road oljstructiima and accidents. This arrangement also 
simnlifies the stperinif 




problem, since the car is 
steered just the same 83 
any other truck, much 
of the complication inci- 
dent to an electric motor 
on each wheel being elim- 

Fig. 356 is a view of 
the whee] with the tire 




In the second illustration, Fig. 357, an axle, either front or rear, 
with the wheels removed, is presented. In this cut the left wheel is 
entirely removed, but the one on the right shows the axle spindle B, 
the method of fixing it in the axle support at C; the armature housing 
D is no^ally within the wheel arid not visible. One feature peculiar 
to this arrangement is the steering, which is effected by means of 
a vertical post with a small spur gear at its lower end E. This 
meshes with a curved rack F, which is machined on the outside of 
a pivoted member G, fo which a pair of arms are attached. One of 
these arms H has a rod /, which runs to and operates the right-hand 
spindle B, while the other J has a similar rod A', which operates the 
left-hand wheel. When all four wheels are to be driven in this 
manner, the post is vertical, but the connection with the rack F 

becomes horizontal, with a continuation to the rear axle which 
operates the various arms, levers, and rods there in the same manner. 
This particular system is used for heavy commercial work only, 
and in this it has been particularly successful as a tractor, a front axle 
and a pair of wheels being substituted for those of a heavy trucking 
wagon. Then, with a sling under the body or beneath the driver's seat 
for the batteries, and with proper wiring, control levers, and steering 
wheel, the truck becomes electrically driven. 

Classification. Generally speaking, front axles may be divided 
into about five classes: the Elliott, the so-called reversed Elliott, the 
Lemoine, the front-drive form, and the fifth-wheel form. 


These tj^pical forms of axles are themselves subject to further 
subdivisions. For example, there are maay different forms of Elliott 
axles, each manufaeturer having what is practically hia own form. 
Again, the Lemoiiie, when used by other firms, has been built in a 
practically new form, taking the second maker's name. Thus the 
fomi of front axle made by Lemoine for Panhard is so different as to 
be called the Panhard, and not the Lemoine. The same is true of 
the Lisses axle made by Lemoine. In this country, it is claimed 
that tlie axles made 1),\- Timken are sufficiently different from the 
Elliott anil reversed P^Iliott, from which the principle was taken, as to 
deserve the name of Timken axles. It should be borne in mind that 
in the following descri|)tion of the various axle types the forms nf 
material, ami the sliape, sii!e, and kinds of bearings used do not alter 


forms a straight vertical cylindiical portion bored for the pivot pin, 
: while the knuckles are so formed as to have jaw ends which go over 
c the axle ends. The thrust comes at the bottom of the knuckle, 
where the axle bed rests upon the upper face of the lower jaw of the 
I knuckle, the axle representing the load and the knuckle the support, 
: just the reverse of the previous case. 

T^his will, perhaps, be made clearer by illustrations. In Fig, 

" 358, as already mentioned, the axle has the jaw ends, and the thrust 

comes at the top. This is indicated in the figure by the letter A, 

which calls attention to the thrust washers at the top. Fig. 359 

shows an axle of the reversed Elliott tj-pe, this being the front axle 


Fj«. 3S0, Revenied Elliot Type of Frool 

Steerinc Knucklo 

for a heavy truck. In this the thrust washers A are at the bottom, 
and are of hardened steel, ground top and bottom to a true surface; 
the upper surface is doweled to the axle, while the lower is doweled 
to the knuckle. This form has the real advantage of concentrating 
all of the difficult machine work and assembling it into one piece, 
the knuckle. The Elliott type, on the contrary, makes the knuckle 
and axle difficult pieces to handle in the machine and afterward, this 
being shown in the cost. Ease of machining the bed of the axle 
is a great advantage, for the axle will average about 44 inches in 
length for a standard tread of 66} inches, and longer for wider treads, 
up to a maximum of about 4S inches for the wide-tread standard in 
the South. 

v^ iiuiu and machine these pt 
than an axle of cnrrespondin^ 
Lemoine Type. The I>t 
those described in that the ax 
of the knuckle-pin part of the 
that is, an extension or a jaw o 

With this design, the thrust loud 
upon the knuckle, whicli also m 
in a sidewise direction at but one 
side shocks are taken on the en 
end, whereas with the other ty( 
two supports, or divided ivi—"-- 

m ir ^^^^^^^^H 


Interted Lemmne. A novel type of axle has been created in the 
1916 Overland car, Model 75, called an inverted Lemoine. In 
this type, as Fig. 360 shows, the wheel spindle, or stub axle, is at 
the top of the steering knuckle instead of at the bottom as in the 
case of the regular Lemoine type. The knuckle has a single, fairly 
long support in the end of the I-beam front axle, the foiling being 
much simpler on this account. In fact, this makes the axle nearly 
straight, which doubtless accounts in large part for this unusual 
design. One real advantage of this design is that It allows the car 
weight to be low in relation to wheel bearings, thus assisting in steering. 

Marmon Self-Lubricating Axle. The new Marmon front axle. 
Fig. 361, is of the inverted Lemoine type similar to the Overland, . 
shown in Fig. 360, but at first glance it looks quite different. For 
one thing, the bearing in the axle end is different, and in this 
lies an exclusive and valuable feature. The stub-axle pivot pin, 
made integral with the stub axle, is placed in a split bushing, which 
is a tightfit at the bottom — where the thrust collars are formed in it — 
and at the top, but not in the middle. When this bushing is in place, 
the knuckle and bushing are forced into the axle end from above, 
and a kind of hub cap screwed on at the bottom. This holds it 
permanently in place. 

n(. 3&Z. Front Elevtticn d C*t, B 

Like the Ch-erland, this arw"- 


and most all pavements are made with a camber. The center of the 
road is made higher than the sides so that the road will drain. It 
is necessary, in order to have the lower spokes plumb or perpendicular 
to the road surface, to throw the center line of the wheel out of the 
vertical plane 2 or 3 degrees. This otTset is also called camber, and 
it complicates the construction of the axle ends to such an extent 
that they must be machined with this slight angle either in the 
knuckle or in the axle, or distributed over the two places. 

Fig. 362 shows the effect of this camber upon the front appear- 
ance of the car, the slight angle of the front wheels giving the car a 
bow-legged appearance. 

Gather Further Complicates Axles. What the carriage men 
term "gather" further complicates the axle ends. This is the practice 
of setting the axle so that the front wheels are closer together at 
the front than at the rear, that is, they toe in. The idea of tliis is 
to make steering easier and, more particularly, to make the car 
self-steering on plain, level, straight-ahead roads. It is scarcely 
noticeable from in front, but is from above. Although many cars 
still have it, it is not used as much now as formerly. 


The materials utilized for front axles include castings of steel, 
manganese bronze, iron, and other metals, in the form of forgiiigs, 
drop forgings, drawn or rolled shapes, and pressed shapes. Wood 
has been but little used and only in the past. 

Cast Axles. Castings for front axles have been looked upon 
with grave doubt and fear by designers and owners, because of 
the fact that road shocks are more severe for front than for rear 
axles, and because of the fear that a casting may have a blowhole 
or some other defect. In addition to the natural distrust of castings 
for this work, it was feared that such material would crj'stallize more 
quickly than would a better and more homogeneous material like 
steel. There is, of course, a certain amount of crystallization in all 
materials, but far less in a close-grained fine-fibered structure like 
forged or rolled steel than in any form of casting. Aside from this, 
castings present many other advantages which are well worth while. 
Thus, the spring pads may be cast int^ral with the axle with prac- 
tically no extra charge, while the same forged integral with a droy- 

.^.^ mxn ana IS aistrus 

it have flown in the face of po) 
mistrusted it even more than the 
ing has been little use<1, and tht 
with a cast axle now on the mark 
Fitfgings. Forgings, as disti 
much used for good front axles, but 
of one excellent truck builder, stri 
world, who is using a hand-forgei 
shown in Fig. 359. It is forged d' 
steel and the ends worked out so a: 
2J-inch section, which later has bt 
This made a very costly piece of 
shown in actual work more than mai 
be found to pay the price demanded 
Many smaller makers follow c 
work allowing the axles to be forgi 
easily, and more cheaply. The sn 
be heated, the less difEcult will be 
will progress be made. The genci 
however, is to turn o\'er the axle jo 
of whom employ drop forgings, dr 
dron-fn"-""* — -■- 


the method itself produces better quality, for any process which 
works steel or wrought iron over and over again improves its quality, 
provided the steel is not burned in the process of heating. Not only 
are the majority of axles made of drop forgings, but of those not so 
made some part is almost sure to be a drop forging, as, for example, 
those made of steel tubing which have their ends or other parts 
made by the dropHforging process. In Fig. 363 is shown a drop- 
forged axle used on a truck. 

Tubular Axles. The I-beam section of front axle is universally 
used, and while the tubular tj-pe formerly enjoyed some popularity, 
its use today is confined to a very few vehicles. When employed, 
its ends are drop forged or drawn, or rolled steel may be used 
with the ends welded or otherwise secured. The disadvantage of 
the tubular type is the fastening of the ends which is more or less 
offset by the lowered cost of material. 

Kg. 3S3. TVpiml Drop-Forged Aile U«ed on Truck 

Drop-Forged Ends. Nearly ail the ends for axles made in this 
way are drop forgings, very few castings being used, while the spring 
pads, or spring seats, as they are sometimes called, are split into 
upper and lower halves and bolted on. 

The loading conditions of all front axles are such that the load 
rests on the axle at two points inside of the supporting points — 
the wheels. Thus, tlie continual tendency of the load acting down- 
ward and of road shocks acting upward is to bend the center of 
the axle still further downward. Since a tube which has been bent 
once has been weakened, it follows that this tendency to weaken it 
presents a further source of trouble. 

Pressed-Steel Axles. The pressed-steel type of axle, which 
made its initial appearance in 1909, and is not genen^'^ eov^^'o^c^, 
consisted of a pair of pressed-steel channel duw\iea — o'ca Nwiv"^ 



slightly larger than the other — set together with the fiaoges 
inward so as to present a box-like shape. When thus arranged, the 
two sections were riveted together by a series of rivets running ver- 
tically along the center part of the channels. The ends eon-iist of 
drop forgings, machined to size or Space between the channels when 
assemhled, and then .set into place lietween the ends and riveted. 
The presscd-stcel construction obtained a secure attachment to the 
JK-d. This iixli- was of tiie Elliott reversed type. 

Change of Axle Type Simplifies. Often the change from one 
type of a\le to rhc otlier is not made Iwcause the latter is better but 
hecanse of some iiicirlfntal saving in the manufacture. Thus, in 



Classification. Thus far nothing specific has been said about 
axle bearings. These are, according to construction, of three kinds; 
plain, roller, and ball. From the standpoint of the duty which 
they are to perform, bearings may be divided into radial-toad and 
thrust bearings, all three forms mentioned above being used for 
both purposes, but arranged differently on account of the difference 
in the work. Each one of the three classes may be further subdivided. 
Thus, plain bearings may be of bearing metal or of hardened steel, 
or they may even be so constructed as to be self-lubricating. Again, 
plain bearings may mean no bearings at all as in the old carriage 
days when the axle passed through a hole in the hubs, and whatever 
wear occurred was distributed over the inside of the hubs, resulting 

after a time in the necessity for either a new set of hubs or a new axle, 
or for the resetting of the axle, so that the hubs set furtlrer up on a 
taper. Roller bearings may be of several classes, some makers using 
both straight and tapered rollers. In addition to these there are 
combinations of the straight and tapered types, and bearings with 
two sets of tapered rollers acting back to back, the action being that 
of straight rollers, with the end-adjustment feature of the tapered 
type. There are also many types of ball bearings, as, for example, 
plain ball bearings — those working in flat races, those working in 
curved races, those working in V-^rooved races, and single twUa 
working aiooe. Here are also combinations of ba)\a m. ^q>9^« to«%. 


Roller Bearings. Fij;. 359 shows the use of tapered roller bear- 
ings for the hubs and of hardened-steel thrust washers for the thrust 
toad, the figure showing, in addition, a plain brass bushing in the 

• axle for the knuckle pin to turn in. In Fig. 3fi5 is shown a more 
elaborate use of roller bearings of very excellentdesign. In addition 
to the axle bearing, it will be noted that the top bearing of the steer- 
ing knuckle is of the roller type. 

Bali Bearings. Although there is a growing tendency to utilize a 
short adjustable tjpe of roller bearing, mani' designers favor the bull 

- bearing. The two most common forms are the cup and cone type, 
which cares for radial and thrust loads, and the annular form which 



radial loads. At the top is tinother ball bearing arranged for 
thrust; this bearing taking up all thrust loads from the weight above 
or from road inequalities. Fig. 367 illustrates the cup and cone type, 
This design utilizes ball bearings for the hubs and plain steel thrust 
washers on the knuckle. 

Alignment of Front Wheels Troublesome. The lack of align- 
ment of front wheels gives as much trouble as anything else in the 

front unit. This lack not only makes steering difficult, inaccurate 
and uncertain, but it also influences tire wear to a tremendous extent. 
As Fig. 368 indicates, even if the rear axle should be true with the 
frame, at right angles to the driving shaft, and correctly placed 
crosswise — correct in every particular with the shafts both straight 
so that the wheels must run true — the fronts may be out with 
respect to the frame, out of track with the rears, or out with 
respect to each other. 

In order to know about the front wheels, they should be mea.%- 
ured; while tihis sounds simple, it is anything Wl tVisA.. \ti. ^Ifte ^srS<. 



place there is little to Dieasure from or with. A good starting place 
is the tires, and a simple measuring instrument ts the one shovm in 
Fig. 369. This instrument consists of a rod ahout 1 inch in diameter 
and about 3 feet long, fitted into a piece of pipe about 2 feet long, 
with a square outer end on each, and a set screw to hold the mcAii- 
urements as ohtaine<I. By placing this rod between the oppoate 
sides of the front tires, it can be ascertained whether these are par- 

riK :UiH. DinnTun, ahoinn* Froni 



with the frame Unes, and whether the wheels are perfectly parallel. 
Given the frame line, too, it can be determined whether the wheels 
track with one another. 

Straii^tening an Axle. When an axle is bent, as in a collision, 
a template is useful in straightening it. This can be cut from a 
thin sheet of metal, light board, or heavy cardboard. It is an approx- 

Flf. 370, AccuTBte 

Better Dwcn than 

imation at best and should be used with great care. Fig. 371 shows 
such a template applied to an axle which needs straightening. 

When the axle is bent back to its original position, a pair of 
straightedges laid on top of the spring pads will be of great assistance 
in getting the springs parallel, as the worker can look across the 
straightedges with considerable accuracy. This is indicated in the 

Pic. 371. TemplxU tot 8lwwin( i[ Aile Ii Bent 

first part of Fig. 372, which shows the general scheme. It shows also 
how the axle ends are aligned, using a large square on top of a 
parallel bar, but of course this cannot be done until the last thing, 
at least not until the spring pads are made parallel. 

Front axles of light cars may be straightened without removal, 
provided the bend ia not in the nature of a twist and not too eiunl. 
Take two iiardtTOod p/ants /feetlong, 1.0 u^cVeawAie.MA'i'vM^Ma 


thick. Next, cut four ^-im-h blocks 10 inches long and '.i inches wide. 
Lay the blocks flat between the planks, space tliem iilwiit 2 fret apart, 
and bolt the whole securely. This obtains a girder 7 feet long, 10 
inches wide, and 4| inches thick. Next, take two pieces ()r 4 X 4 limber 
3 feet long and cut a tenon on one end of each. Make three J-inch 
eye bolts, 12 inches long, with nuts and plate washers for each. Place 
one of the eye bolts between eadi pair of bl(]cks and screw up the nuts 
and washers sufficiently so as to rivet them. This permits of moving 
the eye bolts to any position between the blocks. Two small steamboat 
ratchets and several short but strong chains complete the equipment. 



For example, a downward bend can be straightened by placing the car 
above the girder, connecting the axle to the girder, and using a short 
screw jack to remove the bend. This device can be used with success 
in shops dealing with light- or medium-weight cars. 

Spindle Troubles and Repairs. Wear of the spindle, or knuckle 
bolt, and its bushings, as weUasplay in the steering-gear linkage, brings 
about wobbling of the front wheels when the car is in motion. Some 
experienced persons mistake wear of the knuckle and the bushings for 
play in the wheel bearings, and attempt to remedy the trouble by 
adjusting the bearings. It is a simple matter to determine the com- 
ponent at fault. To test for bearing play, drive a block of wood 
between the knuckle and the axle, then grasp the wheel at the top and 

Fie. 373. Use of Wedgo to Cure a Wobbling Wheel 

bottom, or at points diametrically opposite, and test for looseness. 
If none exists, the play is in the knuckle pin and its bushings. The 
remedy is to fit new bushings and new knuckle pins. 

Wobbling Wheels. Wobbling of the front road wheels is gener- 
ally due to play in the joints of the steering mechanism, arid it is not 
only troublesome, but also sets up undesirable stresses on the steering- 
gear linkage. This flapping of the wheels may be present with the 
steering gear and linkage in perfect operating condition, and similarly 
when the springs, hangers, etc., are in good condition and the proper 
toe in, or. gather, of the wheels exist. 

When the wheels wobble it may be assumed that the front s^rvxv^ 
have so settled that the steering pivots are not c\\\\te Net^XcsWot^ ^X!l\ 


aft, particularly with reference to that t^v-pe of pivots which do not 
incline outwards and where the wheels are canted or dished to briog 
their points of ground contact in line with the pivots. A cure for this 
trouble is to place wedges between the front springs and spring seata 
so as to alter the angle of the steering pivots, as shown in Fig. 373. 
^letal wedges are used, about J inch thick at the large end, and 
tapered toaknifc-likcedge. The wedge is placed at the forward end of 
the axle, and a little experimentation will give the results desired. 
In wedging, as few wedges should be used as is necessary to obtain the 
desired result. 


III arriLiijjing -.i logii'al presentation of the numerous components 
of the nmtor vehicle, the cha.ssis is separated from the body. It 
includes the power pliiiit and mechanism utilized in transmitting the 
energy of the engine t<i the road wheels, also the frame and suspen- 
sion, the axles, ete. However, only frames, springs, and shock 
absorbers will be discussed in this section, as the other parts of the 
chassis havi- been treatetl. 

Characteristics of Parts. Frames. The chassis frame practi- 
is till' fonnilatiiiii of a motor vehicle, since all of the power 


Springs. The primary function of the spring is to absorb the 
•id shocks that would otherwise be communicated to the mechanism 
d passengers. Considerable progress has been made tn the past 
ar toward improving springs, and not only are they better pro- 
rtioned, but improved material and methods of mounting have, to a 
2at extent, eliminated breakage. The leaf type, developed by the 
rse-drawn carriage industry, is the form miiversally employed on 
>tor vehicles, both pleasure and commercial. { 

A review of the 1916 springs for cars showed that the three- 
.arter and seven-eighths elliptic spring was favored by 46.5 per cent 
the makers, while some form of cantilever spring was second with 
.7 per cent for rear suspension. This year the advocates of the 
ntilever have gained many new recruits. In the matter of front 
rings, the semi-elliptic may be said to practically monopolize the 
Id. The coil spring is a thing of the past. 

Shock Absorbers. The fitting of shock absorbers as standard 
uipment is not as noticeable as it was in 1916 and the year previous. 
le use of high-speed engines with light reciprocating parts, and the 
iployment of high-grade light material in other components of the 
assis, together with better springs, ser\'es to absorb shocks created 
■ traversing rough roads. A few makers supply shock absorbers, 
it, as a rule, the car manufacturer leaves the selection to the pur- 
aser. Many different types of shock absorbers are marketed, and 
e is made of varying principles. 


Qeneral Characteristics. When the automobile was first intro- 
,ced, comparatively little attention was paid to the frame, as the 
tier components of the chassis, such as the power plant, gearset, 
les, etc., were held to be of greater importance, consequently the 
ime did not receive the consideration it should. After experiencing 
nsiderable difficulty, however, due to accidents and other failures 
lich were traced directly to poor frame design, the automobile 
gineer found that it was possible to build a frame of great strength 
th less weight than the troublesome types. This statement applies 
the frame of the commercial car as well. 

The improvement in frame design is the result of the tendency to 
ovide perfect alignment of the powei plant, du\^, wcA ^ 


making use of what Is known as the unit power plaiit on somi* nwHlels, 
white on others, particularly of the lieavjep type, flexible mountiDK 
of the units has been resorted to. The tendency is toward the use of h 
flexible mounting of all individual units, at least to aome degree, in 
order to relieve tliem of the stresses brought about by frame weaving 
when the road wheels mount an ol)Stac!€ on the road surface. 

Classes of Frames. The most prominent types of frames, dJvidoi 
according to their use. are the pressed-steel frame, the structural 
frame, and the structural I-beam frame; the latter is coiifiiifd to com- 
mercial cars, ' These classes may be subdivided according to the 
general construction and material; &s well tii to the distribution of 
the chassis units. 

The material employed is either pressed or rolled steel. The 
wood frame or combinations of wood and metal frames are practically 
a thing of the past, and a re to be found, with one or two exceptions, on 
old cars. The steel frame may bt? constnicteil in the following shapes: 
channel. L-beam, angle, T, Z, tubing, Hat plates, and combinations 
of any two or more of these. Other forms are possible. For example, 
the channel may be turned with the open side in or out, the two coti- 
atructions being widely different; or the angle may have the comer 



bent upward or downward at the ends or in the middle really differ 
from those frames which preserve one level from end to end. The 
practice of bending the chassis frame is very prevalent of late, 
the uptm*ning of the ends bringing about a lower center of gravity, 
making for stability and ease of entrance and exit to the body. 

Tendency in Design. There is a marked tendency toward mak- 
ing the chassis frame wider at the rear and narrower at the front. 
In one or two cases the designer appears to have gone to the extreme 
in this respect. The advantage of the narrow front construction is 
that it enables the car to be turned in a shorter radius. The use of a 
wide rear frame provides more space to support a wider body. A 
more recent development is to make the longitudinal bars of the frame 
parallel over the front spring and near the rear spring, and to have 
them tapered from behind the front to the rear springs. A certain 
amount of material is said to be gained by this construction, as no 
heavy reinforcement or sudden offset is necessary to the frame. By 

Fi^. 374. Typical Automobile Frame of Pressed Steel 

widening the frame at the rear it makes possible the placing of 
the springs directly underneath the frame. Some car makers have the 
sides of the frame straight over the entire length, but tapered from 
the front to the rear. 

Fig. 374 illustrates what is termed a single drop or a kick-up. 
This is a type of pressed-steel construction, of channel section, and 
the deepest and strongest section is at the center where the greatest 
stresses occur. Some frames are built with a double drop, having 
a downward bend just forward of the entrance to the rear part of the 
car body, followed by an upward turn just back of the same entrance. 
The upward turn at the back is carried higher than the main part of 
the frame for the purpose of obtaining a low center of gravity. Then 
there is what is termed the bottle-neck construction, a bend inward 
which resembles that in the neck of a bottle. This obtains a short 
turning radius. Originally, frames were narrowed in front, the diStet- 
ence in the width between the front and rear be\xv^ «X fe:^\. ^xi\»!^ 



or so on each side, gradually increasing iintil it btcamc 5 and 6 inches. 
This type did not prove efBcient, and the trend favoretl the tajwr 
previously explained, 

A not uncommon form of frame is show^l in Fig. 375. which pom- 
pensates for an abnonnal rise of the rear axle without the possibility 
of its striking the frame. Some frames have a bend at the ends to take 
the spring fastenings. 

Pressed-Steel Frames. The pressed-stecl type of frame is verj- 
popular with designers and is largely used on commereial cars up to 
and including 1 -tun capacity. This is popular because it is the lightest 
in weight for equal strength of the structural iron or niUetl channel 
and I-beam section. The cost of pressed steel is somewhat higher. 


SubrFrames. The modern tendency is lo eliminate the sub- 
frame — a step due to the flexible mounting of the power plant and 
unit construction — because it simplifies the frame. It has also been 
made easier by the tapered frame, which is narrowest at the front 
where the units are attached. The most common method of support- 
ing the engine is the three-point. Sub-frames are used, however, as 
they serve the purpose both of supporting some unit and of strength- 
ening the frame. j 

Sub-frames may be of two kinds, viz, those in which the sub- 
frame is made different for each unit to be supported, and others 
in which one sub-frame supports all units regardless of size, shape, 
or character of work. The type of sub-frame made to support each 
unit usually works out to two pairs of cross-members, one for the front 
of the unit and one for the rear; while the type which supports all 
units regardless of size works out to longitudinal members, supported, 
in turn, by two cross-members, front and rear. The added weight for 
the first-mentioned type is less than for the other, since it comprises 
only four cross-members; while the last-named type consists of two 
cross-members equal to two of the others and of two very long members 
parallel to the main-frame members, each much longer and thus 
much heavier than the corresponding cross-members. In the two 
frames already shown, Fig. 374 shows the unit type of sub-frame with 
only cross-members, while Fig. 375 shows the more modern type in 
which the power plant is of the unit type and rests directly upon the 
main frame, being the three-point suspension type in which the 
forward point is on a frame or special cross-member, while the rear 
two points are the crankcase supporting arms resting directly on the 
main frame. 

Rigid Frame. A pressed-steel or rolled-stock rigid frame has its 
advantages, particularly with reference to the commercial vehicle. 
It permits the body to be rigidly secured to it, and as it does not give 
with the inequalities of the road, the body is not racked. An advan- 
tage of the rolled stock is its cheapness, except, of course, for the 
lighter models of the assembled type for which frames can be secured 
at low figures. Another advantage of the rolled stock is the ease 
with which the wheel base may be altered. 

Effect on Springs. The effect of frame construction upon the 
design and duty of springs should be consideTed. TVx^ \^'aX.\»^ 



is not generally understood, but it has an important bearing upon the 
life of the car. A rigid frame relies upon the springs to allow for all 
axle displacement. If a front and a rear wheel on opposite sides are 
raised several inches at the same time, the frame is subjected to a 
torsional stress. If the frame is rigid, springs of considerable camber 
must be employed in order to absorb the shock without being bent past 
the limit of safety, and they must be suflBciently flexible to absorb all 
the shock without any tendency to lift the other wheels from the 
ground. To accomplish this shock absorption, a different type of 
spring is used on a rigid chassis from that employed on a flexible 
frame. The use of underslung spring suspension has come into favor 
for this reason, as it permits the frame to be carried fairly low, without 
sacrificing spring camber or necessitating a dropped rear axle. 

The flexible frame, when diagonally opposed wheels are raised, 
does not impose all the stresses on the springs but it absorbs 
a part of them. For this reason, springs on a flexible chassis 
are flat or nearly so, with a limited amount of play. Flexible con- 
struction also permits the frame to be carried equally as low as with 
the imderslung spring, and yet the spring is perched above the axle, 
where it is more nearly in Une with the center of gravity, thus reduc- 
ing side sway. 


Pressed Steel. Pressed steel is purchased in sheet form, cut to 
the proper shape in the flat, and then pressed into channel form under 
great pressure. It is made of steel rolled into sheets and is somewhat 
closer grained than ordinary steel. There is no breaking of the flake 
in the rolling process. The pressed-steel frame, as previously pointed 
out, permits of greater simplicity in assembling, since the parts can be 
easily bolted or riveted. Fig. 376 is of the type of pressed-steel frame 
having a tapering section, a kick-up at the rear end, five cross-members 
— one of them a tube — ^and is narrowed in at the front to give the 
largest steering lock. Otherwise it presents only standard practice. 

Wood. Wood is universal and easy to obtain. While no longer 
classed as cheap, it is not expensive; moreover, wood is kept in stock 
nearly everywhere. Users of wood for side-frame members claim 
that the wood frame is not only lighter but stronger. Iiv »ddvl\wv^ 
the .wood frame would undoubtedly possess more xvatvit^ ^V^\sv% ^"^^ 




Comparative Strength of Steel Channels and Laminated Wood PraraH 





Pressed Steel 


13x6 . 





534, sro 

resiliency, so that if would make a lighter and easier riding frame. 

A section of a wood frame is shown in fig. 377. 

This shows a frame made of laminated wimxI. There are three 

very thin sections of selected ash, marked /I, which Bregluttl together, 
then screwed and bolted to pre- 
\ent the glue from opening up. 
To further this purpose, a strip B 
IS f,istt nnJ on the top and iMtttffD 
in tht same manner. These strips 
are laid with the grain running 
luinzuntally, while the niatu 
pietes are laid )\'ith the grain 
runnmg vertically. This con- 




The Fergus car was developed as 
a result of fifteen years' experience in 
fine repair work, and is an attempt to 
eliminate the usual "owner troubles". 
While not intended as a "foolproof" 
car, the Fergus comes nearer being one 
than any other developed up to this 
time. In addition to actually "tooU 
proofing" the car, the aim of the 
makers was to eliminate much of the 
work incident to caring for the modem 
car by replacing the usual "owner- 
attention" with an automatic system. 

In the frame, a combination of 
steel girder and lattice work has been 
produced which has the appearance 
of being absurdly light. However, as 
the diagram of stresses in its members. 
Fig. 378, indicates, everjihing has been 
figured out with the utmost care, and 
the design has been supplemented by 
unusual workmanship. 

The complete frame. Figs. 379 and 
380, shows that a large part of the 
saving is produced by the method of 
suspending the units^. W^ these 
hung on the side members, as in the | 
ordinary case, the frame certainly 
would not do, but aa it is, they are 
hung on immensely strong brackets, 
steadied by the side members, but 
rigidly supported by large tubular 
cross-members. The brackets and 
cross-members do the work ordinarily 
assigned to the side members of the 
frame, the side members simply joining 
and holding together the various brack- 
ets and cross-members. 




varying from 11^ to 16 inches, serves as the bottom flange of the 
frame, anf! is therefore of Z-section. The vertical section of the frame 
is 10 inches high, and has height enough to replace the running board 
fenders wittiout appearing narrow. At the front and rear ends of tlie 
frame, the running boards are curved upward, strengthening the frame 

as well as suppiirtiiig the fenders into which they merge. The frame, 
beyond these points, both forward and rearward, is made of channel 
section of the con^'cntional type. The rear of the frame is 45 inches 
wide and tiipcri^ to :iO inches at the front spring hangers. The great 
dfpth of till- friinie section makes it very stiff, so that the body siils 



Steel Underpans. The underpan has assumed a great deal of 
importance in the last two years, for makers have more and more 
realized that it is highly important to protect many of the parts from 
road dirt, flying stones, water, etc. ' Designers have, therefore, given 

Fig. 383. Two-Pieoe Prewed-Steel Underpan Used on Winton Cars 
Courtesy of WiiUon Motor Car Company, Cleteland, Okie 


considerable attention to its shape, size, and method of attachment. 
In some types, it apparently runs underneath both engine and trans- 
mission and is made more or less a part of the main frame. There- 
fore, its quick removal on the road would be difficult, if not impossible; 
yet road accidents sometimes make it necessary for the driver to take 
this pan off to get at the lower side of engine, clutch, or gear box. 

For this reason, underpans generally resemble more closely that 
shown in Fig. 383. This is a side view, showing the semicircular 
form of the pans, as well as the two-piece construction. The forward 
part under the engine, which would be taken 
down fairly often, is held in place by three 
spring clips on either side. Lifting these 
clips off is only a second's work; in addition, 
there is a filler piece in front, helping to make 
the pan fairly air-tight. The depth of the 
pan increases slightly toward the rear, so as 
to form a slope down which liquids, will 
drain; the rear end is fitted with an upturned 
elbow, so that it will not drip until it accu- 
mulates a considerable quantity of liquid. 
Continual dripping indicates a full charge, 
and the pan is drained by turning the elbow 

In Fig. 384, a detail of the arrangement of the pan shown in 
Fig. 383 is presented. This indicates both the permanent part of the 
underpan, which is attached to the frame, and the removable part, 
which is freed by loosening the spring clipa aYvown. 

Fi«. 384. Detail of Spring 

and Section of Wintou 




Commercial-Vehicle Construction. Commercial work, being 
rougher, harder, and cheaper work, changes the frame construction 
just as it does everything else about the car. In Fig. 385, a 
commercial-vehicle frame which brings out this point is ^own. 
The main sills are 6-inch channels, while all of the other members 
are correspondingly large angles and channels. In one place the section 
consists of a box shape made up by bolting two large channels together, 
with the open sides in. The total overall length is not given, since 
this differs according to the variations in the wheel base; but, by a 
comparison of the figures given, it is seen that the frame shown is in 

excess of 210 inches long by about 37 inches outside width. This is 
about twice the total length of the average small car. 

In the bracing and arrangement of the different members, this 
frame shows other points of difference, the cross-members, for 
instance, being nine in number, not including the two diagonal 
cross-members. The longitudinal members, too, are eight in number, 
not counting the two diagonals. 

Rear-Eiid Changes. The locating of the fuel tank at the rear of 
the chassis — a practice that was brought into favor largely through 
the introduction of the vacuum system of fuel supply — has resulted 
in a number of changes to the rear ends of frames. The placing of 
the fuel tank at the rear is not new, and probaVAy \\, 'wqkM. 'ct!5\.\v%M«. 

Fie. 387. Sketch of Rm 

esaendal to strengthen the reai 
carrying the spares inflated on ( 
erable weight to the rear of the 


extension for attaching the fuel tank. A cross-member is also utilized ; 
it serves as a point of attachment for the two rods supporting the 
lower apron and for two upper rods as well. This design has merits 
in that the tire carrier is firmly anchored and serves to protect the 
fuel tank from injury possible in operating in crowding tra£5c where 
rear-end collisions are not uncommon. As may be noted, Fig. 386 
shows the method of using an upper cross-member to prevent theft 
of the tires. 

A different type of rear construction is. shown in Fig. 387, a Reo. 
Here the rear cross-member is gusseted, and a pair of substantial arms 
are riveted to the cross-member. These arms serve as an anchorage 
for the tire holders which, in turn, have a cross-rod for protection. 
Still another design is shown in Fig. 388. Here the side rail of the 
frame projects back of the rear cross-member of the frame for a dis- 
tance of about 12 inches. The fuel tank is suspended from these two 
extended frame members by means of steel straps which pass around 

the tank. 


The more usual troubles which the repair man will encounter 
are sagging in the middle; fracture in the middle at some heavily 
loaded point or at some unusually large hole or series of holes; 
twisting or other distortion due to accidents; bending or fracture 
of a sub-frame or cross-member; bending or fracture at a point 
where the frame is turned sharply inward, outward, upward, or 

Sagging. A frame sags in the middle for one of two reasons, 
either the original frame was not strong enough to sustain the load 
or the frame was strong enough normally, but an abnormal load was 
carried, which broke it down. Sometimes a frame which was large 
enough originally and which has not been overloaded will fail 
through crystallization or, in more common terms, fatigue of the 
steel. This occurs so seldom, and then only on very old frames, 
that it cannot be classed as a "usual" trouble; moreover, it cannot 
be fixed. 

When a frame sags in the middle, the amount of the sag deter- 
mines the method of repair. For a moderate sag, say i to J inch, 
a good plan is to add truss rods, one on either side. These should 
be stout bars, well anchored near the ends oi the Itama wA ^\.^\»Xa» 


where the frame has not been weakened by excesaive (irilling. They 
should be given a flattene<l U-shupc, with two (or more) uprights 
down from the frame between them. The material for tliem should 
be stiff enough and strong enough to withsUind bending and shoulii 
be finnly fastened to the under side of tlie frame. The tru^s rods 
should be made in two parts witli a tunibuckli? to unite them, the 
ends being threaiUt! right and left to receive the tumbuckle. 
Wlien truss rtKls are put on a saKged frame, it should Ix; turned 
over and loadetl on tlie under side; then the tiimbuckles slioiiUI be 
pulled up so as to force the middle or sagged pari upward a fraction 
of an int-h, say | to { inch, and then the frame turned back, tlie 
other parts added, and the whole returned to use. A job of this 
kind which takes (jut the sag so that it dfies not recur is a job to Be 
proud of. 

Fracture. Many frames 
break because too much metal 
waa driUed out at one place. 
Fig. 389 shows a case of this 
kind. The two holes were 
drilled, one abo%-e the other, 



crack, subsequent drilling should be at an angle, to avoid a repetition 
of the overloading condition. In the figure, the dotted lines surest 
the drilling. By staggering the holes in this way, there is a greater 
amount of metal to resist breakage than would be the case with one 
hole above the other — a method which might preferably have been 
used in the first place. 

So much welding is done now, and so many people know of its 
advantages, that every repair shop of any size should have a weld- 
ing outfit. A frame job is essentially an inside bencfi job, but a 
large number of cases of welding could be done directly on the car 
outside the building, particularly in summer when the outside air 
and cooling breezes are desirable. So, it is well to construct a small 
truck on which to keep the 
oxygen tank, acetylene cylin- 
der, nozzle for working, and a 
fire extinguisher. One form 

of a truck is shown in Fig. /i^ 'M^ fySENC 

390. This truck is a simple 
rectangular platform with 
casters, a handle, and a rack 
to hold the tanks. It saves 
many steps and is particu- 
larly convenient in summer 
months. This outfit is essen- 
tially a home-made affair, but , 
the gas-welding and electric- 
welding manufacturing companies have designed small outfits espe- 
cially for automobile repair work, which would be preferable to the one 
in Fig. 390, especially where the amount of repair work warrants a 
reasonable expenditure for a welding outfit, A description of both gas 
and electric outfits and instructions for their use are given in the 
section on Welding for Automobile Repair Work. 

Riveting Frames. Tightening Rivets. Rivets securiAg the cor- 
ners of a frame or holding cross-members, gussets, and plates often 
work loose, particularly with the flexible type of frame previously 
alluded to. The location of the rivet and the accessibility of the part 
will determine how best to proceed with the work. TV\fe (ivv^S X-xwiS^ 
experienced is tba t of placing a sufficiently sotid articXe a^««\.'CBft'ciN^ 

3iy-Acetyleae Outfit 

-u«i lur cutcing off nvets as wt 
should be of sufficient length 1 
When an anvil is not avail 
with success. Take a J-inch b 
in the frame between the rivets 
bolt with a cold chisel. Put on 
and run the nut down until i 
depression in the head of the bol 

Fi|. 391. Method oC Riveting F 

it, drill a larger hole and use a I 
made of Norway iron. Heat to ( 
Riveting Methods. There are 
in and the backing in. The latt 
the two plates to be riveted are < 
at A, with the rivets a trifle sni; 
at B. With hot riveting, the hoi 
the rivet, but with coid rivets, 1 



by a head formed at the dolly end of the rivet, and additional blows of 
the hammer tend to bring, the plates closer and to hold them. The 
backing-in method is practical in making the various styles of rivet 
heads, particularly in making the thin, almost flush, head, and an 
advantage is that there 
are no reactionary 
stresses upon the thin 
head as would exist with 
the driven-in rivet. 

As there is more 
demanded of the rivet 
replacing the old mem- 
ber, it is important that 
the work be carefully 
performed. This applies 
to the holes in the plate. 
All sharp comers should 
be removed, as they af- 
ford an opportunity for the rivet to shear off by external stress 
or to fly off under internal strain. A reamer, drill, or countersink 
can be used in removing sharp corners. The face left need not be 
more than A or A inch wide, in order to greatly strengthen the rivet 
at its weakest point, or where the head joins the body. By slightly 

Fig. 392. Adding a Tnias Rod to the Front of a Weak or 

Damaged Frame to Stren^^then It and Preserve 

the Radiator 


^fterT'/in^ JTrofbr" 




Fig. 393. Bracing Fractured Frame with Bar and Tumbuckle 

chamfering the corner of the plate, the rivet is given a corresponding 
fillet, which not only increases its holding power but serves to draw 
the plates together. 

Frame Bracing Methods. There are several metitioAa ^>aet^^ ^ 
frame that has been injured through collision or Yiaa ^»^%^ >aeica.>aafc 


of too light construction can be repaired. The front of the frame is 
the chief ofTender in this respect, and many times a leaking radiator 
is the result. When repairs to the radiator fail to cure the trouble, it 
may be assumed that the frame is at fault. A simple remedy is 
shown ill Fig. ;i02 nnd consists in bracing the frame by means of a rod 
iiiid turribucklc. The rod should be about 2 inches longer than the 
wiillli nf tlie frame and threaded for about 3 inches on each end. 
The tiiriiliurkle is not essential, but it simplifies the work. In 
itislalhiig the brace, the inside nuts are screwed on first and far enougli 
til allciw putting tlie rod in place. These nuts are next screwed out 
until they bear against the frame, and the latter is forced out until 
any pressure that may have existed on the radiator is eliminated. 
The outside nuts are then screwed up snug. The advantage of the 
turpbuckle is that adjustments may be made as required. 

rig. 393 shows a method of trussing a frame that was fractured 
by the stresses of the motor starter. Even after the fracture had 
I)een repaired, the driving gear of the starter would not properly i 
with the ring gear on the flywheel of the engine. As the movement ' 
was up and down on the frame, a truss was found necessary: while it 
latter t CI attach one end of the truss on the left-hand side 



the ends. When these are used, the centers of the springs are attached 
top and bottom, respectively, to the frame and axle. With half of 
the top of the spring cut away, and the cut, or thick, end attached to 
the frame, this spring becomes a three-quarter elliptic. When the 
whole top of the spring is cut away, so that the spring is but a series 
of flat plates, bowed to a long radius, this becomes a semi-elliptic 
spring. By turning the semi-elliptic spring over, it becomes a canti- 

Fig. 394. Typical Semi-EUiptic Front Spring 

lever when its center and one end are attached and the load applied 
to the other end. The quarter-elliptic is but a quarter of a spring, 
while the platform consists of three semi-elliptics — two as side mem- 
bers in the regular position, while the third is used as a cross-spring, 
being inverted and attached at the center to the rear end of the frame 
and at its ends to the side members. The coil form requires no expla- 
nation and is not now used on cars. In addition, these forms are 
modified by scroU ends and various attachments. 


Fig. 395. Typical Full-Elliptic Front or Rear Spring 

Semi-Elliptic Fig. 394 shows a front spring of the semi-elliptic 
type, the form which is used now for almost every front spring. 
This is a working spring of the usual type, fixed at the front end, 
shackled at the rear end, attached to the axle in two places, and with 
two rebound clips in addition. The latter are put on the springs 
to prevent them from rebounding too far, in the case of «b n«^ Ar«^ 
drop* In some cases, as high as four, six, or eigVvt ol \]iies^ ^vv^ ^E&a:^ 


be used. Many other springs are made with ears, these being clipped 
over the next lower spring plate, the final result being the same as the 
use of many clips, but with improved appearance. 

Full-Elliplic. Full-elliptic springs are the oldest form known- 
Fig. 395 shows the construction of this type, the upper and lower parts 
being pivotally connected at tlie ends. A slight modification of this 
form, known as the scrull-end full-elliptic t,\-pe, is in more extensive 

Fiu :>'.Hi Full-Elliplii! »pting nith Scroll Endu 

use than tht? full-elliptic plain tj-pe. As Fig. 396 shows, the ends of the 
upjier leaves arc bent over. Euch carries an ej-e, which is connected to 
the eye in the end iif the upper leaves of the lower half of the spring by 
means (if a shackle. This construction makes a very soft-riding spring. 
Three-Quarter Elliptic. Very much like Fig. 396 is the form 
elliptic spring, the one having scroll ends 



greater increase. One reason for this increase is the great increase in 
the number of dropped frames, that is, frames unswept at the rear. To 
this form of frame, the three-quarter elliptic spring is very well adapted 
and makes a very natural, very good,and very easy-riding combination. 
Platform. The platform type of spring is used a great deal on 
large cars, as well as on very heavy trucks, on account of its ability 
to carry heavy loads well, and also on accoimt of its flexibility. 
As may be seen in Fig. 398, it consists of three semi-elliptic springs 
shackled together at the comers. The rear cross-spring is usually 
made shorter than the two side springs, while the latter are set off 
center, making the front of the spring, that is, the part forward of 
the point of attachment to the axle longer than the part to the rear. 
There are two reasons for this: First, the front end acts somewhat 
as a radius rod, the rear end of the frame rising in an arc of a circle 
whose radius is the front half of the spring; second, this plan dis- 

Fig. 398. Platform Spring, Showing How Side- and Croes-Springs Are Shackled Together 

tributes the spring action equally in front of and back of the axle. 
Since the rear cross-spring is fastened to the frame in the center, 
each half of it is considered as a part of the side spring to which it is 
shackled. Thus, the total. length of the side spring in front of the 
axle is the measured length of the side spring, while the total length 
of the side spring back of the axle is considered as the side length 
plus half of the cross-spring length. The center point, or point of 
axle attachment, is not moved so far forward as to make these two 
lengths equal, but in a proportion which may be derived thus: Assmne 
a side spring 42 inches long and a cross-spring 35 inches long; then the 
spring would be set out of center some 4^ inches, making the front 
length about 25| inches, while the rear length would be 16| inches plus 
half of the .rear spring, or 17| inches, making a total of 34 inches. 
This would give a ratio of 25^ to 34, or 1 to 1 .333. If the side mem- 
bers were 50 inches, the ratio would be about 1 to 1.25, and fot ^vi^ 
members shorter than 42^ the ratio would be about \ \jc> \ Jb. 



Cantilever. Tlie cantilever is, in appearance, a semi-«Iliptic 
spring turned over. It gK'ts its name, however, from the method of 
siis|K'nsi(>n, ivliicli is qnite different from that of any form of semi- 
elliptit- sj>riiij;. IMort-over. as a part of this suspension, at least one 

end of tin- caiitilivcr aiifi sometimes two are finished up flat and 
sqimre to sliitc buck ami forth in a groove provided for that purpose, a 
bolt thronjrli a «■ ntrai liole preventing the spring from coming out of 
its tjiiLiif. Oiif ftiriii, ^ill<)wn in Fig. 399, has a fixed attachment 
to tilt' rear a\!e. a iiivnti-d attachment to the frame at its center 



the King, is pivotally mounted on the frame just forward of its center. 
Unlike the King, however, the forward end of the spring has a shackle 
which permits it to swing when the rear axle rises or falls. This 
shackle is a very interesting feature of this installation, having an 
adjustment which is most unusual for a shackle, Fig. 401. Note how the 
outsides of the shackle 
have a series of grooves, 
into which the head of 
the shackle bolt on one 
side and the washer on 
the other, fit. By setting 
these in the desired 
grooves and tightening 
the nut, the position is 
fixed. If this does not 
give the proper throw, it 
is a simple matter to re- 
move the nut and make 
a new adjustment. 

In France, a form of i;« spnog 

double cantilever has been tried out with success; this form consists of 
a pair of cantilevers, one above the other, separated at the center by a 
•carefully sized spacing block, which is pivotally attached to the frame. 
The rear ends are attached above and below the axle, while the front 

ends are attached to two fixed points. Although the ends are made 
much thinner and more fiexible than those just shown, it should be 
noted that both of them are fixed. The nse and fall of the wheels 
must be taken up by the springs themselves, the pivot in the center 
simply distributiii^ the distortion over both the ItoiA aD,4TCM.\«SN«». 

rods, the main lead may be : 

Fit. 403. Uniqua . 

and the torque act through tl 
metal in the line to the thrust, 
thethpiixf o-J - ' 



In the Hotchkiss drive, the springs are rigidly attached to the rear 
axle, while the front end of the spring is secured to the frame with a 
proportionately large bolt through which the drive is transmitted. 
Users of the drive claim that it is quieter, that the car holds the road 
better, that it is more flexible, and that it avoids the road shocks 
which are transmitted through stiff torque members from the axle 
to the frame. Makers who drive through the springs and employ 
other torque members claim that they are not sacrificing flexibility in 
driving while eliminating a certain side sway and other strains preva- 

Fig. 404. Combination Cantilever and Semi-ElUptio Spring on Tractor 

lent when the springs perform the functions of the torque. In the 
Hotchkiss drive, two universal joints in the drive shaft are used. 

Unconventional Types. Marmon. A departure from conven- 
tional practice is the spring used on the Marmon car and shown in 
Fig. 403. It is a double-transverse construction, consisting of semi- 
elliptic springs bolted together at the center, with a curved block, or 
hard-maple cam, between them. This cam varies their stiffness, 
the spring automatically becoming stiffer as the load increases. 
Under normal load, the stiffness is about 170 pounds per inch^ but ^.^^ 
the springs are compressed the stiffness w\l\ reacYv 400 pouxv^^- 'W^^ 



are shackled at one siile an<l fixed at the other, obtMning a perfectly 
parallel iiiDtinii to tile frame. There is said to be no roll as is some- 
times fi)iiiiil with trjiTi^verse springs. 

Kiiiij^ Tni'ior. An unusual method of suspension is that 
employed on tlie Kiuix tractor, a combination of a cantilever and 
semi-clliptic spring at the rear end of the frame. The design shown in 

Fig. 404 incluiles lieavy semi-elliptic springs, which are attached to 
the rear axle hy linif: clips and carry the fifth wheel of the trailer. 
There is no cnnnectinn lietween the springs and the tractor tiantB, 80 
eight of the trailer and load only. The tractor frame 

g having a pivot near its center and a 



Witdon. Many makers use their own special form of springs. 
Fig. 406 shows the spring formerly used on the Winton cars, a type 
which might be described as a double-purpose spring. It was made 
in two parts, the lower part consisting of a regular semi-elliptic flat 
spring, while the upper part was a semi-elliptic fiat spring with scroll 
ends. The central part of the spring was treated as one, being 
attached to the axle in the usual manner; the ends, however, had a 
peculiar appearance, because the upper and lower halves of the spring 
were of different shape. The scroll end of the upper part was sup- 
posed in itself to absorb many of the small road shocks. The spring 
was loosely attached to the frame at each end by means of a double 

Fie. 407. Thn!e.<]iurt«i BaoU Elliptic Spriuv on Winton Car 

shackle, made necessary by the double action of the spring; the tend- 
ency to flatten out increased its length, thus calling for a forward 
motion of the front and a backward motion of the rear ends, while the 
different lengthening action, owing to the difference in the lengths of ■ 
the two parts of the spring itself, resulted in a turning about a different 

For comparison with this earlier Winton spring, the latest form 
is shown in Fig. 407, It will be seen that the three-quarter elliptic 
form has been adopted, with a kick-up at the rear end of the frame. 
If the two tj-pes are compared somewhat closely, it will be seen that 
the only change in the frame part is the kick-up. The ue-w 's?.'"^^ 
show the scrol] ends to whjcb Winton has al%'ays\>een v&ttjveX.. 



Ford. The form of tlie Ford spring has always been distinctly 
liiffert'iit. Fig. -lOS shows the front and Fig. 409 the rear spring used 
on FonI Oiirs, the distinction in the front spring being principally 
in tlie use of a single ordinary inverted front spring set across the 
frunie on toj) of the nxle, where most makers use a pair of side springs 
set piirallel to tlie frame. This form is simple and cheap to mftke 
iind assemble, tlic tost of tlie spring itself, an<l the work of putting 

it on licing jn>t ai>ont half that of the spring attachment of the 
(iniiaiiry two-spring ty|)e. On the otiier hand, excellent riding quali- 
ties are ehiiiMfil f<ii- it. A second distinction is that the spring is 
an itiviTsiiin of the nsnal semi-elliptic type, the set of the spring 
lii'ing dowi^ward instead of upward. A third claim to distinction is 
ill tlie use of v.iiiaclinrn steel, which, it is claimed, has a higher tensile 
a[id eotn) (restive strengih than any other steel, and it is practically 
liibreiikitlili' in tirrsinn. This steel is also being used in many other 



the construction necesatating it These springs represent quite a 
radical departure, the success of which has been proved in actual 

Locomobile. Fig. 410 shows the three-quarter scroll elliptic rear 
spring used on the Locomobile, also the method of shackling both ends 

Hi. ilO. Tlin»4iuitet Bcrull EUiptio Sprinc Uaed on Locomabils Cui 

of the spring, and the use of a considerable extension beyond the spring 
clip of the two upper leaves. Fig. 411 illustrates the Locomobile 
front springs, the upper spring being used on the 1916 model, and the 
lower one on the 1917 model. As may be noted, the later type is 
2 inches longer and also flatter, and the distance between the spring 

F^. 111. Two BcU ol FroDt-Aile Sprino on Locomobila Cm 

bolt and eye of the shackle is less in proportion to the 1916 design. It 
was found that the jerky action and fore-and-aft pitching of the axle 
were eliminated by this constnictioD, greatly improving the riding 
qualities of the vehicle. 

Eleetrie Car Spring. The spring suspension of electric i^U«a»s«. 
cars is similar to that o{ tbe gasoline vehicte, Bent\-«Va.v^i)vc vis^-o^n'Ci 


ifi front, am! full-elliptic scroll-end suspension at the rear. The 
methdi! of sluicklinj; is similar. 

Varying Methods of Attaching Springs. Springs are attached 
in many ways. For example, tlie one shown in Fig. 398 might be 
shackleii at the front end, fixed to the axle, and fixed to the center 
of the frame at the rear, the side and cross-springs heiog shackled 
together. Again, the front end might be fixed to the frame, Fig. 412. 
all other ciimiectiuns being unchanged. Or, with either method of 
fixing tlie front end, the spring might be swiveled on the axle, so as 
to be free to give sidewise without changing the other properties of 
the spring. Or, with either method of fixing the front end of the 
spring, and with or without flie axle swivel, the cross-spring might 
be pivoted at the central point so as to be free to turn in any direction 


its length, that is, in the coib, without tr^isferriiig any of them to 
the body proper or, in case of heavier shocks, sharing with the side 
and rear springs. This, of course, is the true function of the 
springs— to allow the road wheels to pass over the inequalities, 
rising and falling as may be necessary, while the body travels along 
in a straight line, level and parallel with the general course of the road. 
UTtderslinging. Almost any of the spring forms shown and 
described may be underslung, that is, attached to the axle from 
below. This is a quite common practice for semi-elliptic springs when 
used in the rear, but it is very uncommon for front springs. Similarly, 
full eltiptics, whether having scroll ends or not, are frequently under- 

ni. 113. ttetr-Spriuc Amnaameiit OD 1917 

slung. The three-quarter elliptic form when used in the rear is 
usually underslung; the platform spring is not underslung so often. 
The cantilever and quarter-elliptic springs have been mentioned in 
connection with the underneath attachment. It should be pointed 
out that the position beneath the axle lowers the center of gravity by 
an amount equal to the thickness of the spring plus the diameter of 
the axle plus twice the thickness of the attaching means, and this, too, 
without interfering with the quality or quantity of the spring action. 
In the case of the cantilever, the effect of underslin^g is to reduce the 
straightness of the spring, that is, the form when attached above 
the axle is almost straight, while the form whea {aste^vni \i*i.w« "^sR- 
axle is veiy mudi curved— has coosideiable "opemn^" . 



Shackles and Spring Homs. Considerable improvanent has 
taken place in tlic mctl»Ki of shackling springs, and providon is now 
made witli some types of springs for the adjustment of the shackles 
and hiinpcrs as w ell us for renewing bushings. Reference has been 
made to tlie teiuleiuy of design in rear-spring suspension and to the 
undertiluiig ty]Ks. Fij:. 413 shows the design employed with the 1917 
Premier, and, as may be noted, the springs are slightly diagonal, the 
front ends coining inside the frame line, while the rear ends are attached 
to g(«>sc ne<-ks of a rear extension of the frame pieces. Shackles are 
used for coiniectiiit; the ends of the springs to the extensions. 

A dcjuirlnre from the conventional shackle is the safety double 
shackle used un the Itainer 1000-pound capacity delivery car, shown 
in Fi^. 414. In addition to the main eye on the main leaf of the rear 
spring, the second leaf is extended 
and formed into an elongated eye, 
allowance being made for deflection 
under load. The eye of the leaf is 
attached to tlie frame by the usual 
rigid spring bolt. Additional n 
; furnished t 



removing the cap of the grease cup, the hanger bolt is turned out, or 
to the left, with a screwdriver, decreasing the distance between the 
links. The ' grease-cup body and lock nut are then set up tight. 

Ks. 41fi. Svotion of AdjuMible Fraot-^priiic 

Provision is made with some types of rear springs for eliminating 
play when the rear ends are mounted on seats. 

Spring Lubrication. All springs now are fairly well lubricated. 
All shackles are provided with grease cups, and other points of attach- 
ment to the frame are provided with oil holes. Where the springs are 
pivoted either on frame or axle, a big grease cup is usually furnished. 
In addition, it is now realized that the maker can prevent much of 
the noise formerly coming 
from dry and perhaps rusted 
steel spring plates working 
over each other. There are 
several ways in which oiling 
is accomplished. The springs 
are made with an internal 
lip, or groove, which is filled 
with lubricant when they are 
assembled; or between each 
pair of spring leaves is placed 
an insert having a aeries of oil pockets throughout its length, each 
filled with lubricant normally held in by means of & TQ«n!bT«.T^« (s:iN«t\ 
the movement o/ the spring plates and the ^eat een.etB,\»^ ^«n^'^ 

. ^uisiiuwtnatpracucai 

the nOmber of these clips vai 
use to which it will be sub, 
three clips and a band. Son 
two bands. But none indica 
jections on the ends of the le. 
leaf next below it to assist ii 
. are in quite general use. All 
of spring-leaf ends, but those 
These are: the oval; the roun 
fication of the oval; the roui 
form, widely used on motor 
the diamond point. 

In addition, sizes have 1 
extent that only five widths aj 
motor trucks. Those for the f< 
for the latter: 2, 21, 2i, 3, 3i, 

As the automobile busii 
qualities under more severe c 
used has been greatly improvec 
French make excellent springs 
facturers going abroad for thei: 



temper; they sag and show signs of losing their set; plates break in the 
middle, at the bolt hole, and near the ends of the top plate; and inside 
plates break in odd places. But more frequently the springs make an 
annoying noise, a perceptible squeak, because the plates have become 
dry and need lubricating. When this happens, and the up or down 
movement of the car rubs the plates over each other, dry metal is 
forcibly drawn over othey dry metal with which it is held in close 
contact; naturally, a noise occurs. 

To lubricate the spring, it is well to construct a spring-leaf 
spreader. Of course, the job is best done by jacking up the frame, 
dismounting the spring entirely, taking it apart and greasing each 
side of each plate thoroughly with a good graphite grease, then 

Fig. 417. Handy Tools for Spreading Spring Leaves to Insert Lubricant 

reassembUng it, and putting it back under the car. This is the best 
way, but it costs the most, and few people will have it done. Some- 
times spring inserts are used; these are thin sheets of metal of the 
width and length of the spring plates, having holes filled with lubri- 
cant over which is a porous membrane. 

For the ordinary spreading job, the plates must be pried apart 
and the grease inserted with a thin blade of steel, for instance, a 
long-bladed knife. To spread the leaves, jack up the frame so as 
to take off the load, then insert a thin point and force it between a 
pair of leaves. In Fig. 417, two forms of tools for making this forcible 
separation are shown. The first is a solid one-piece forging with 
the edges hardened. It is used by sliding the edges ovet tSoa «cAa. 
(rf the spring leaf, then giving it a twist to fotce Vt Vxi\>^\*^««^^^2ai^ 


springs are handled, a rack lik 

Broken Springs. WTien s 
remedy — a new plate or plates 
it is necessary to get home. 

Flf. lis. Sunplo and 1 

shackled end, repair this sufiicien 
bar with a hole in one end big en 
this bar to the spring in place of 
General Hints on Spring Re| 
takes place where it does not pr 
should be borne in miml ti-"* *'- 


ness, but an expert spring maker should be called in to see that the set, 
or fit, is correct. The fitting of a leaf requires the services of an 
expert spring man; while it appears to be a simple matter, the lack ■ 
of knowledge by some claiming to be spring experts is responsible for 
breakage after the spring has been repaired. The spring clips and the 
nut of the center bolt should be kept tight. The importance of 
preventing the accumulation of rust on the leaves and of lubrication 
has been commented upon. 


Function. The ordinary flat-leaf springs of any of the types 
previously described are inadequate for automobile suspensions. 
When the springs are made sufficiently stiff to carry the load properly 
over the small inequalities of ordinary roads, they are too stiff to 
respond readily to the larger bumps. The result is a shock, or jounce, 
to the passengers. When the springs are made lighter and more 
flexible in order to minimize the larger shocks, the smaller ones have 
too large an influence, thus keeping the body and its passengers in 
motion all the time. These two contradictory conditions have created 
the field for the shock absorber. 

The shock absorber is generally a form of auxiliary spring, the 
function of which is to absorb the larger shocks, leaving the main 
springs to carry the ordinary small recoils in the usual manner; in 
short, to lengthen the period of shock. This is done in a variety of 
ways, and, as might be expected, by a great variety of devices. 

General Classes of Absorbers. The simplest forms of absorbers 
are the ordinary bumper, or buffer, of rubber and the simple endless 
belt, or strap, encircling the axle and some part of the frame and 
acting as the rubber pad does^-simply as a buffer. There are the 
following classes of the more complicated shock-preventing and shock- 
absorbing devices: (1) frictional-plateorcam, in which the rotation of a 
pair of flat plates pressed together tightly — one attached to the frame, 
the other to the axle — opposes any quick movement of the two or of 
either one relative to the other; (2) a coil spring used alone and in 
combination — alone it is used in the plane of the coil, or at right 
angles to it, and parallel to the center line about which the coil is 
wound, while in combination it is found joined with the simple leatK« 
strap or with another ooil spring of equal ot 90TEie^)aas» cK. V%& 

to the frame, having at ita outei 
^milar plate at the upper and * 

Jersey CUy. JVeu Jeraty 

this type is called the governed fric 
When cams trt- "'■— ' 



sharp jounce, the device becomes effective. It appears much like the 
•Hartford just shown, but the construction is decidedly different. 
The upper, or frame, arm is threaded to receive an Acme-threaded 
screw, which is carried by the lower, or axle, arm. The action of 
screwing this out tends 

Fig. 420 

Laporte Paaaive Range Friction Type d 
Shock Absorber 

C<ntrU9y of CharUt Laporte, Detroit^ Miehigon 

to force the plate on the 
lower arm, which must 
move outward with the 
screw against a rubber 
washer held firmly by the 
outside nut and cover 
plate. Thus, the scissors 
action of the two arms 
on a sudden movement is 
resisted by the compres- 
sion of the rubber washer. 
This compression can be 
increased or decreased by tightening or loosening the slotted outside 
nut, so that the screw is given less or more movement. The rubber 
washer is made with a series of holes in it to allow of compression. 
Coil Springs* Alone and in Combinations. Springs Alone. 
The coil-spring absorber is probably the most widely used form, 

primarily because it is rcr-.^-- ri-r:::^- 

both good and cheap; z3 bl^™ J irv-ZTr^^^^c:::^^ 

furthermore, it is simple 
and adds little weight. 
In most instances, the 
coil is so placed as to 
compress along the direc- 
tion of its center line. 
One device, however, the 
Acme, shown in Fig. 421, 
works at right angles to 
this. It consists of a pair 


Fig. 421. Acme Torison Spring Fitted to Three-Quarter 

Elliptic Gears 

Courtesy of Acme Tornon Spring Company, 
Botton, MoMoehutetU 

of coils, the two ends of each being so constructed as to go on the 
ends of the shackle bolts in place of the usual shackle. Wlien the 
shackle is removed, one pair of ends is fastened to the spring in. 
place of the shadde, while the other pair of euda lafc^sA \jei >iafc Vtwxs^fc 



:tached to the lower end of the spring and encircles the axle. Hence, 

lis will not interfere with upward movements of the axle, but 

ily with the downward ones, that is, the axle is free to rise, but as 

■on as the car body starts to rise, the 

rap-spring combination acts to prevent 

. This is particularly true if the axle 

13 reached the limit of its motion and 

13 started downward before the body 

arts upward. In that case, the body 

.n move upward only the amount of 

ick in the strap plus the give of the 

iring, but minus the amount the axle 

IS already moved downward. This inex- 

insive arrangement has found great ^^vXC 

VOr on small cars. Hg. 42f Hoovi^r shuck Absorber, 

Double-Coil Spring Types. In prin- courun ht h. w. iioorrr Compan». 
pie, the use or two spnngs is not tJiffer- 

it from the use of one. For stiuctural reasons, however, it is easier 
attach the two-spring form, while dividing the load up into two 
irts allows of the use of 
laller diameters and smaller 
les of wire, thus making the 
;vice appear more compact, 
le of the two-spring forms, 
e J.H.S., is shown in Fig. 
5. It consists of a pair of 
linders with coil springs 
thin. The tops of the two 
linders are joined by a pin, 
d this Joining pin is attached 
the lower leaf of the spring, 
side the cylinders, pistons 
e set above each spring, and 
ese are connected, this con- 
ction being used for the 
her half of the spring. At the bottom, the external bands on 
ch of the two cylinders are coimected, so as to keep them ^anlleV. 
all times. Thus any movement upwatd ol ^e Yo'wcc ^ax^ ^ 'd^« 



main-leaf spring tcniis to Hraw the enclosure for both shock-absorbing 
springs upward. The springs themselves resist this and absoH) 
a large part of the niiiveiiient both in force and distance. 

Flat-=Plate Recoil Springs. The third class, or flat-leaf spring, 
is a senii-clliptic unit in miniature. It Ls placed upon the top of the 
ordinary semi-elliptic spring, but it is reversed and has a spacing 
plate between the two. The object of this plate is to prevent recofl 
and to eliminate the rebound of the car body without restricting the 
flexibility of the main springs. As shown in Fig. 426, the Amea 
equalizing spring is constructed along these lines. As will be noted, 
this allows all downward movement of the spring, having no influence 
thereupon; but when the recoil, the upward equal and opposite 
reaction, comes, the smaller upper spring opposes this reaction and 


In the drawing, A ia 
the upper section of the 
cushion chamber, telescop- 
ing into the lower section 
made up of -tube B and 
crosshead E. The outer 
tube C is simply a guard. 
A steel casting D is bored 
out to form a guide for the 
outer tube and crosshead, 
and has a rectangular pad 
F machined for bolting the 
whole device to the bracket 
attached to the frame of the 
car. A shackle G is fastened 
to the end of the car spring / 
and is pivoted to the cross- 
head E. Packing ring H is 
used to make the inner cyl- 
inder a tight fit in the outer 
casing. A breather J is 
placed on the side, through 
which air is drawn by the 
upward movement of tube 
B through the medium .of 
the tightness of packing ring 
H, Just mentioned, and this 
air, on the downward move- 
ment, is forced through the 
passage K to a port partly 
surrounding the tube B. 
There is no packing ring 
between this tube and its 
guide D, so the air blows 
out and keeps the contact- 
ing surfaces clean. A fur- 
ther protection is afforded 
by the felt-wiper ring L, 



which retains the grease in the g^oo^'e just ahove it. is a rod «>ii- 
nei.'ting the two front or rear springs. At the top is the screw 
cap M, covering the air val\e N, which is designed to be used just 
as the air valve in a tire. 

The lower part of the device is filled with oil up to a level which 
approximates the line Z, all above this level being air under pressure. 
Consequently, the device actually compresses the air through the 
medium of the oil, which is incompressible. This oil forms a sen! for 
the air chamber and prevents its leakage, although the oil itself is 
allowed to leak through, this leakage being pumj>cd bark auto- 
matically by the action of the springs. This works oufas follows: 



When a road obstruction is met and the spring rises, crosshead 
E rises and the upward movement of the oil takes the disc X upward 
until it strikes and carries with it collar V, which lifts the plunger and 
draws in a charge of oil. When the air compressed in the upper 
chamber of the device expands, and the car spring / and crosshead 
E go down again, the oil flows in the opposite direction, carries disc 
X down against collar W, and forces the plunger downward. Then 
the oil passes the ball check Y, goes through the hollow plunger, and 
is discharged back into the upper, or air, chamber. In the first place, 
the oil is put in by taking off cap M and taking out the air valve N. 
Then a special single-acting oil gun is used to force it in, a long nozzle 
being necessary to reach down into the interior, with a stop to limit 
this downward distance. The maker recommends that an excess be 
put in and then slowly drawn off to the right level. 

Fit' 42D. Ty^ol Hemi-^liptic 

As will be seen from the foregoing, this device is essentially an 
air spring, and the air cushion does the work; but it is the oil below 
it, with its permissible leakage and with a pump to return this leaking 
oil, which makes this device practicable. To show the exterior, 
the part which most persons would see and remember, Fig. 428 
is presented. This figure shows the rear end of a Pierce limousine 
equipped with a pair of the Westinghouse air springs. Note the 
breather, tie rod, cap at the top, cast guide at the bottom, and other 
parts previously shown and described. 

Hydraulic Suspensloiis. The majority of the hydraulic devices 
developed as shock absorbers consist of turning vanes connected to 
the axle or spring, enclosed in a liquid-tight case filled with some heavy 
oil. There is a hole of small diameter in the case which connects the 
two sides of the vane, its motion fordng the fluid through thiB bole. 

shown in Fig. 429, or it may 1 
block. Where coi! springs are i 
Attached either to the frame en) 
springs are used, one on each sit 
elliptic. It is attached to s in 
free so that they may make coi 
or a pad on the pressure block of 
load has been applied. With 
motmted on a seat forged integr 
box dips; a coil spring is attached 
bumper. Under excessive deflec' 
flange of the ft^me and arrest 
spring. The Jeffery Quad empit 
of flat metal and is termed a voliiti 
fastened to the pressure block. 



Q. Which wheel travels far 

A. The outer wheel must ti 
turn, because it is turning througl 
longer radius. On ver>' short t 



Q. How does the usual steering arranKeineiit care for this? 

A. By having the linkage which connects and steers the front 
wheels arranged so that a prolongation of the center lines of the two 
steering arms will pass through the center of the rear axle. 

Q. How does this solve the difficulty? 

A. When this arrangement is used, any swing or turn given to 
the steering system, say a turn to the right, will swing the left-hand 
knuckle through a larger angle than the right, although the two are 
connected together by linkage. This means that the inner, or left, 
wheel will swing about a shorter radius than the outer, or right, wheel, 
since if the two were turned through equal angles, the two radii would 
l>e equal. 

Q. What other items coniplk:ate this steering problem? 

A. The fact that the wheels themselves must toe in slightly at 
the front in order to steer easily and hold a straight line when set 
straight. Furthermore, the wheels must be set with their tops wider 
apart than their bottoms so that the' line through the center of the 
plane of the wheel strikes the cambered, or raised, road surface at a 
right angle; this makes the whole situation even worse. 

Q. Is the ordinary front axle of such a design that it gives per- 
fect steering? 

A. No. But it represents a working approximation which could 
not be improved upon without many needless complications. On a 
sharp turn, probably one wheel is dragged around the curve for a 
small portion of its length, but the distance is so small that it would 
never be noticed by the eye tior discovered in any difference of life 
in the tires. 

Q. How is the turning of the steering knuckles about their 
pivots obtained? 

A. The swinging movement of the steering knuckles is obtained 
through a fore-and-aft movement of the steering rod connected up to 
one of the steering-knuckle arms by a ball joint. 

Q. How is this longitudinal movement of the steering rod 

A. By a fore-and-aft swinging of the steering arm attached to 
the steering gear. 

Q. How is this fore-and-aft movement of the steering arm 

Q. Why are the worm and th 

A, The worm is used to secu: 

few fonns of mechanism which will 

the entire group in the reverse dir 

movement of the wheels to be tran 

against the driver's wishes. In adc 

to care for, wears little, and ts highl< 

Q. What other forms of mecf 

A. Bevel gear, screw-and-nL 

full gear as distinguished from w 

gear, simple bent lever, and other fi 

Q. What are the disadvantj^ 

A. With the exception of the 

or partially reversible, so if the fn 

shock is transmitted back to the dri 

Q. How are steering wheels 

A. In various ways. Some i 

uoderside of which the arms of the : 

Others have the arms cast integral ^ 

are of bronze with a molded rubber 

Q. Is the wood form, with spi 

A. It was, but it is rapidly 

better. This construction is now u 


Q. What is the importance of the cross-rod at the front axle? 

A. It is the only member tyijig the two steering knuckles 
together. If this rod is bent, the wheels cannot be steered accurately; 
if it is broken, they cannot be steered at all. In fact, the car cannot 
be moved forward when the rod is broken. 

Q. Why is the rod usually placed behind the front axle? 

A. As a protection against damage from high spots in the road. 
If it is back of the axle, it is well protected; but if the design places 
the rod in front of the axle, it has no protection, and trouble is likely 
to ensue on rough roads. 

Q. Where is the front end of the steering rod carried? 

A. As a similar means of protection, the steering rod is fre- 
quently carried over or above the front axle, so that the axle will 
protect it. Even when the design of axle, steering knuckle, and other 
parts necessitates this rod being below, it is placed as close as possible 
to the axle level, so as to get the maximum protection. 

Q. What is the function of the steering knuckle? 

A. It forms a pivot, or bearing, upon which the front wheel 
rotates; but, in addition, it forms the basis of steering, being capable 
of turning about a vertical (or nearly vertical) axis. 
Questions for Home Study 

1. Describe the complete steering mechanism of the Pierce- 
Arrow car. 

2. Why is it better to steer with the front wheels than with the 
rear wheels? 

3. Tell in detail how a worm and sector mechanism works. 

4. Describe the working of a worm and nut device. Is it better 
than a worm and gear and if so, why? 

5. How is the Genuner steering gear adjusted (a) for wear of 
the worms; (b) for looseness of the steering wheel? How is it 

6. Describe the Hindley worm. What are its advantages; 

7. Select and describe one form of steering-wheel construction. 

8. How would you adjust a steering rod for (a) length; (b) 

9. Tell the advantages and disadvantages of the various possible 
positions for the cross-rod ; for the steering rod. 

latter fits in between the two par 

has a single central bearing. 

Q. How does the inverted 

A. In the inverted, or revert 

with a single central bearing, whilt 

-or Y, and has the two bearings, on 

Q. Which of these two forn 

A. There is little choice, bi 

Elliott form because it gives a stiff 

which is generally a good size rig 

can be made large enough in thii 

anti-friction bearings. This b noi 

Q. How Is the Lemoine axle 

A. The steering knuclcle an 

letter L. The axle end is plain anc 

end of the steering pivot. In tin 

its vertical leg eirtending upwards,! 

80 to speak. As constructed in Ut 

is turned downward, so that the a: 

Q. What are the advantages 

A. Both axle end and knuc 

structed more cheaply. Moreover, 

or disassembled more readily and qi 


Q. What are the usual axle materials? 

A. Modem practice restricts front axles to hand- and drop- 
forged steel, to tubular centers with forged ends, and to pressed steel. 
The latter is little used, however. Cast steel and manganese bronze 
as well as wood, have been used. 

Q. What are the usual axle bearings? 

A. Ball, roller, and plain bearings are widely used. For the 
sake of simplicity and compactness, the steering-pivot bearings are 
often plain, while the wheel bearings on the knuckle end are about 
evenly divided between ball and roller. Thrust bearings are about 
evenly divided between plain steel bearings with bronze washers, on 
the one hand, and with ball bearings, on the other. 
Questions for Home Study 

1 . Describe a good method of truing front wheels. 

2. How would you determine that front wheels were out of 

3. Describe in detail the (a) Overland front-axle; (b) the 
Christie; (c) the Marmon. 

4. How are axles lubricated, with reference to (a) wheel bear- 
ings; (b) steering pivots; (c) thrust washers or thrust bearings? 

5. What are the disadvantages of cast front axles? 

6. Are ball bearings better than roller bearings for front-axle 
pivots and if so, why? 

7. Describe in detail the process of straightening a bent front 
axle. Would you use a template and if so, why? * 


Q. What is the need for a frame in an automobile? 

A. Every automobile needs a frame, stiff and strong enough to 
support all the units for power development and use, down to the 

Q. Is there any radical difference between pleasure-car and 
motor-truck frames? 

A. None, except that the truck frame must carry a much heav- 
ier load and, therefore, needs to be stiffer and stronger and that it 
must cost less relatively, thus necessitating a form or shape which is 
cheaper ta construct. 

Q. What materials are used for frames? 

Q. Is steel tubing used for 

A. Frames are no longer coi 

this has been tried, but some d 

for the support of the engine, 

Q. Is structural steel widel} 

A. For pleasure cars very U 

but in gradually decreasing quan 

better and cheaper frames of pres: 

Dating any and all arguments in 

Q. What Is a frame "kick-u 

A. When the rear end of a 

level is bent sharply upwanis fro 

inches, beginning just forward of 1 

rear end of the frame on this highe 

called a kick-up. 

Q. What Is the purpose of a I 

A. It lowers the central part i 

a lower step, incidentally lowering 

the car safer. It raises the rear ei 

Q. What is the sh^e of the 

A. It is gradually assuming 

the frame formed a rectangle, wit] 

was found advantageous to narrov 

for tlio »iv."t "■! — '" '- • - ' ■' 


then became a logical step to make the frame taper from front to rear 
continuously, with straight sides. This is the form which all frames 
are assuming now. 

Q. In what other ways do modem frames differ? 

A. The rear cross-member is being eliminated very widely, as 
is also the front cross-member, so the triangular-shaped frame is not 
closed at either end. Formerly, the depth of the frame was pretty 
much the same from front to rear, but now this tapers very materially 
from the front up to the middle and then down again at the rear. A 
good stiff typical frame would be perhaps 2^ inches to 3 inches deep 
at the front, 6 inches deep in the middle, and perhaps 2 J inches to 21 
inches deep at the rear. In short, except for perhaps 20 to 24 inche^ of 
length right in the middle, the frame depth would differ continuously. 

Q. What is the advantage of varying the depth so much? 

A. It eliminates every pound of excess weight, putting much 
metal where there is heavy load and severe stresses and little metal 
where the load and the stresses are Ught. 

Q. Is this form of construction more expensive? 

A. No. The art of pressing the frame out of sheet steel has been 
developed through large quantity production to such an extent that a 
frame of this type, with a constantly varying depth, costs no more than 
a straight frame cost four years ago. 

Q. Does this form give the repair man more to do? 

A. No. On the contrary, frames give less trouble in the way of 
sagging, breaking, or cracking than ever before. The frame troubles 
of today are mainly due to poor or Ijght design, in an effort to lower 
weight too f^r, or to accidents. 

Q. What has been the effect of cantilever springs on frames? 

A. One effect of cantilever springs for rear use has been to 
eliminate the rear cross-member, as spoken of previously. Another 
effect has been to continue the deepest section back quite a few inches 
to the point of support of the front end of the cantilever. 

Q. Is the trussed, or latticed, frame widely used? 

A. No. Only by one or two makers, although a few heavy cars 
have a truss rod below the main frame to add stiffness and strength. 
The trussed, or latticed, frame is a new departure m frame design. 

Q. What are the noticeable tendencies in frame constniction, 
other than those already mentioned? 

change this. 

Questions for Home Study 

1. How would you repair a 
end; (b) center; (c) rear end; ( 

2. Describe the method o\ 
coy-acetylene process. 

3. Describe the following fr 
(b) Marmon; (c) Fergus. 

4. How is the Franklin woe 

5. How is what is called ai 

6. Tell how to remove and 

7. What material is usually 
li^t pleasure car; (c) for a heav 

8. Give the advantages and 


Q. What is the need for veh 

A. To support the load in a 1 
jars of the road will not be transmi 
addition, a flexible connection bet 
wheels is needed. 

Q. How many recognized di 
A. Seven; all of which are n 

itieS for all kinria ..f i^-J 


Q. What is the shape of the semi-elliptic? 

A. This form has a slight bow upwards, the two ends being 
slightly higher than the middle. The middle is attached to the axle 
and the ends to the frame, and when load is applied, these ends come 
down, flattening the spring so that it approaches a straight line. 

Q. Describe the full-elliptic spring. 

A. This form has the shape of two semi-elliptics, one inverted 
and set on top of the other. This gives it the appearance of an elon- 
gated letter O with points at the ends. The lower half is attached to 
the axle and the upper half to the frame, and loading tends to bring . 
the two halves closer together, flattening the O still farther. 

Q. What is the form of the three-quarter elliptic spring? 

A. This consists of a flat lower semi-elliptic member and a 
highly curved quarter-elliptic upper member, the two being joined 
by means of a shackle. With the exception of the difference in 
curvature of the two parts and the use of the shackle to join them, 
this has the appearance of a full elliptic with the upper forward 
quarter cut away. When loaded, both members give slightly, the 
upper quarter more than the lower half. The shackle gives a' consid- 
erable difference in this action from that of the full-elliptic. 

Q. What is the platform spring like? 

A. This spring consists of three semi-elHptics joined together at 
the ends so as to form three sides of a rectangle. The two sides are 
fastened, respectively, to the axle at the middle of each, to the frame 
at their front ends, and to the third spring at the rear ends. The rear 
spring is inverted and its center is fastened to the center of the rear 
end of the frame, while its ends are shackled to the rear ends of the two 
side springs. This makes a combination in which the normal semi- 
elliptic spring action is modified somewhat by the inversion of the rear 
cross-member and by the use of shackles at the ends of all three. 
While popular three or four years ago, it is now going out in favor of 
the three-quarter elliptic. 

Q. What is the cantilever spring like? 

A. It consists of an inverted semi-elliptic fixed or shackled to the 
outside of the frame at the front end, hinged or pivoted slightly 
forward of its center to the outside of the frame, and having its rear 
end attached to the upper or lower surface of the rear axle. It is used 
in greater lengths than any other form of spring and b very popular. 


It is the most simple spring now in use and is said to give tlie easier 
riding of all. 

Q. What is the quarter-elliptic spring like? 

A. Tliis Is simply wliat its nume indicates, one-half of a semi- 
elliptif or oiic'-<|ii;irk'r tif a full-elliptic. Its front end is fixefl to the 
frame out-side, and the rear end is shackled or allowed to slide on the 
rear axle. It is generally inverted. In realitj;, it is a cheap substi- 
tute for the cantilever or inverte<I semi-elliptic, this use being allow- 
able because of the light weight of both car and load. 

Q. Is this used in any different way? 

A. Sometimes ii piiir of these is used, one alxive the other, with 
the idea of dimbling the resistance or rather of giving equal resilience 
with but half the movement. 

Q. What is meant by underslinging? 

A. When this refers to frame, the entire frame is place<! below 
the springs. This has gone out of use. When referring to springs, 
tills means placing the spring below its support, as below the rear axle. 
This construction lowers the frame and center of gravity by the 
thickness of the spring plus its seat plus the diameter of the rear axle, 
sometimes amounting to a. total of five indies. It is growing rapidly 









Units in the Final Drive. Generally speaking, the transmission 
is located in the middle or forward end of the chassis. When this is 
the case, the final drive begins right at the rear end of the transmission. 
The units back of the transmission, then, would be a universal joint; 
a driving shaft; possibly another universal joint; the final gear 
reduction; rear-axle shafts and enclosure; the differential; the torque 
rod, or tube, or substitute for it; the wheels; the brakes; the tires; 
and other smaller units. 

Even when the transmission is placed on the rear axle, this 
general layout is changed little, and the transmission, which has been 
coveFed in detail previously, is not considered again. In the case of a 
chain drive, which is still used on one pleasure car or perhaps two, on 
a number of small trucks, and on a large number of large trucks, this 
layout is changed considerably. In the large trucks, the transmission 
in perhaps 90 per cent of all cases would be in a unit with the jack- 
shaft, which means that for consideration in the final-drive group 
there would be only the driving shaft to the transmission; the joint 
or joints in it, if any; the chains and the method of adjusting them; 
the rear axle and wheels; the brakes; the differential, of necessity 
becoming a part of the transmission; and the jackshafts. 

To make this clear and point out the various units, it will be 
noted in Fig. 430 that it is a unit power plant. Directly back of the 
transmission is the first universal joint, driving through the hollow 
propeller shaft to the rear axle, in front of which is the second universal 
joint. The rear-axle group includes the axle shafts, differential gears, 
final gear reduction, gear housing, and the wheels. The torque 
reaction of the drive, to be explained later, is taken by the torque rod, 
marked in the drawing, which connects the rear axle to the under 


right angles to each other, that is, the forks are laid in planes which 
are at right angles. The fork on one shaft is fastened to a pair of 
diametrically opposite pins, while the fork on the other shaft is fas- 
tened to the other pair of diametrically opposite pins. Each shaft is 
able to turn on its pins about a line through the center of both. As 
these two lines are in planes which are at right angles to one another, 
but intersect at a common center, movement is possible in either 
plane, or by combination movements of both, in any direction. 

Slip Joints. In many situations, a real universal joint is not 
needed, since the parts are not actually free to move in all directions; 
but what is needed is slight freedom up and down or sidewise 
combined with possible fore-and-aft movement. In such cases a slip 
is used, the name giving the idea of a joint which allows one shaft to 
slip, or slide, inside the other. The general constructibn of slip joints 
varies. Sometimes a round gear is fastened to the end of one shaft; 
this gear has a fairly large diameter and many teeth, with the teeth 
chamfered to an unusual extent — almost rounded, in fact. An internal 
gear of the same size and number of teeth with similarly rounded 
profiles is meshed with the hollow gear of the other shaft. Both 
gears have unusually wide faces. ' This combination gives an action that 
is almost universal, and also allows lateral sliding of perhaps ^ inch. 

The second form of slip joint consists of a squared shaft and 
square enclosure. The end of the shaft has a member split along a 
central Une attached to it; the exterior approximates a round of large 
diameter, but the interior is machined to a perfect square, one-half 
in each part of the spUt member. Attached to the end of the other 
shaft is a member machined to an exact square, but slightly rounded 
in a fore-and-aft direction. The square will drive, no matter in what 
part of the housing it is located, so that considerable fore-and-aft 
sliding is possible. In addition, the rounded surface of the square 
gives an approximate universal effect. The split housing is used to 
make assembling and disassembling easier and much quicker. Some- 
times such a housing is put on the end of each shaft, the connecting 
member being made in the form of a dumb bell, but with two square 
ends — one to work in each squared-out housing. In this way the 
effect of a full universal joint with the fore-and-aft sliding is obtained 
at less cost, and with easier assembling and disassembling as extra 

forma have been produced, 
the two shafts bolted to tl 
The metal will bend and g 

Fig. 431. Laminalrcl Dinro Foroiiiu 
Shufl C-oupHng 
CourUn/ tf Thrrm-id AvUxr Comp 
Trenbm. ,%>ir Jir,rii 

end of each shaft, a.s the figun 
convenient for the ronnlr Tr,~ 



Shaft Drive. In its usual form, shaft driving in an automobile 
involves simply a propeller shaft interposed between the rear axle 
and a revolving shaft in tlie car above the spring action. There is 
some provision for taking the torque of the shaft and of the axle so 
that they shall maintain their proper relative positions. 

In Fig, 432, a typical short driving shaft with its two universal 
joints is shown. This is such a shaft as would be used in the car 
shown in Fig. 430, except that the latter is a long wheel-base car with 
its transmission in a unit with the motor and clutch and thus, far 
forward. This combination necessitates a very long propeller shaft. 
The one shown is actually from a car having a short wheel base, with 
the transmission located amidships. This is a combination which 
calls for a fairly short propeller shaft. 

The short shaft, shown in the figure, is a solid shaft. The modem 
tendency toward lighter weights is being worked out in the case of 

Fi|. 432. Ordiury Driving Shift af Solid Form with Two Uaivemil JoinU 

propeller shafts, and many are now made hollow. By making the 
diameter slightly larger and having a large central hole, unusually 
light weight is obtained with all the strength of the solid form. In 
addition, the larger diameter hollow shaft has more rigidity than the 
small diameter solid form, and in many of the modern cars without 
torque or radius rods, unusual rigidity of the driving shaft is necessary. 
Other forms have been used for the driving shaft, but they come more 
or less in the freak class. About two years ago, a car was brought out 
with a spring, or flexible, shaft, which consisted of a rectangular 
member of considerable height, but fairly thin. The idea was not only 
to transmit the power of the engine, but to do it in a flexible manner, 
that is, the shaft was supposed to alisorb all the sudden changes, 
such as quick acceleration or quick braking. At the same time, one of 
the eiectric-car makers brought out a chassis with a square driving 
ahaft of very small size. This ser\'ed the same purpose as the flexible 



tion opposite to that in which the shaft is turning. In some cars, 
this is counteracted by the use of slightly heavier springs on one 
side. The advantages of the shaft drive are the complete enclosure 
of all working elements, with their consequent protection from dirt 
and the assurance of their proper lubrication. 

The final drive of the Ford automobile, in which the end of the 
propeller shaft is shown at .(, together with the bearings in which it ■ 
revolves, the pinion by which it drives the car, the axle, the differen- 
tial, and the bearings of 
the floating inner ele- 
ments of the axle is illus- 
trated in Fig. 4:J3. 

The shaft drive does 
not necessarily include 
the use of bevel gears for 
the final reduction at the 
rear axle; in fact, almost 
aiij- form of gears maj' 
be used. In one well- 
known shaft-driven com- 
mercial car, the final 
gears consist of a pair 
of plain spur gears, while 
on the shaft of the second 
»f these gears is a pair of 

As soon as the bevel 
gear final reduction dis- 
closed its limitations and 
disadvantages, designers started to displace it. One of the earliest 
formsofgearusedfor this purpose was the worm, an example of which 
can be seen in Fig. 4.^. This figure shows the worm placed above the 
wheel, but the lower position, which is aL-to used, haK the advantage of 
copious lubrication. In the form shown, the wheel must come directly 
t>eneath the worm so that the differential may l>e set inside of it. 

The worm is usually more suitable for slower moving vehicles 
which have a large reduction of spool between engine and rear wheels, 
that i^ to say, it is peculiarly fitted to electrics and motor trucks of all 



sizes, on whicli it is finding wider and wider use. On pleasure vars 
of the average size and type where a speed as high as rtO m.p-h. nr 
higher is espect«l hy nil mneemwl, it has not been found suitable and 
consequently is not iieinji^ used, 

A later fomi, wiiicli is designed tti replace the straight bevel, i^ 
the- spiral bevel. ^Tliisis primarily a bevel gear with spinil teeth, the 

*^— i•i^^^^ 

idea being to inciir]K>riile in thc' bevel gear the aj^lvantages of the 
spirally shaped womi tooth, without its disodvautiiges. As Fig. 4:J5 
shows, this makes a \(t_\- compart and neat arrangement, the differ- 
ential fitting within the larger gear in the some mamier as with the 


ihh-Cluiin Drive. The U8e of double chains, by whieh the 
wheels lit" an iiiitomobile are drivi-ii fnim a cfinntershiift 



merits and the means of securing these merits in positive and per- 
manent form will result in their more general use. 

A tj-pical roller chain of the type most used for automobile 
drives is illustrated in Fig. 436. 

Silent chains, of the types illustrated in Figs. 437 and 438, possess 
certain points of superiority over roller chains and are therefore com- 
ing increasingly into use for camshaft drives, in gear boxes, etc., and 
there is some possibility that they will find more extensive application 
to final drives than at present. 

The action of a silent chain is illustrated in Fig. 438, in which it 
is seen that as the chain links enter the sprocket teeth the chain 
teeth at the same time close together and settle m the sprocket with 

■isr fvs/r/or/ 

Fi|. 438. Action of Sileot Chain and ^cwkMi 

a wedging action that causes them to be absolutely tight, but without 
any more binding than there is backlash. 

To keep silent chains from coming off sidewise from the sprockets 
over which they run, it is customary to make the side links of deeper 
section than the center hnks, as is illustrated in Fig. 437. Another 
successful scheme is grooving the sprocket to receive a row of special 
center links in the chain, which are made deeper than the standard 

At present, only one American pleasure car, the Metz, has 
final drive by means of silent chains. This is a small car with a 
friction transmission, the drive from the ends of the cross-shaft being 
by enclosed silent chain to each rear wheel. 

Torque Bar and Its Function. It is a well-known fact that action 
and reaction are equal and opposite in direction, so that if a gear is 
turned fordbly in one direction, say clockwise, there is a reaction in 
the opposite direction, or counter-clockwise. This is the iumple basic 
reason for atorquebar.ortorque rod, on an automobile. It is needed 
with any form of final drive, but it takes different forms, aiceotdv»^V> 



Uie tj'pe of gear iisccl. The bevel and spiral bevel used on S8 per cent 
of the 1917 cars are explained in detail as follows: Fig. 439 shows the 
rear end of a typical pleasure-car chassis. The engine is rotating 
clockwise, and so is the driving shaft A, as shown by the arrow. The 
shaft turns the pinion B in a clockwise direction, which rotates 
. the large bevel C so that its top turns toward the front of the car. 
The bevel C turns the rear axle I) and the rear wheek (not shown) 
in the same direction; so the car moves forward. 

In addition to tlie gear C and shaft D turning easily in the axle 
housing K, there is an eijiial and opposite reaction which tends to keep 
them stationary, while the bevel pinion B and driving shaft -I tenii 
to rotate around the rear axle a? u center in a counter-clockwise direc- 



Driving Reaction. As has been stated, the power, or torque, of 
the motor is used to rotate the rear wheeb. These stick to the pave- 
ment or road surface, so 
the car is really pushed 
forward. Since it is this 
pushing action which 
really moves the car for- 
ward, it b very interest- 
ing to note how thb push 
is transmitted from the 
wheeb and rear axle to 
which they are attached 
to the frame which car- 
ries the body and pas- 
senger load. 

The transmission of 
the drive to the body is « ,.„ rv . e , ■ t^ ■ o ^■ 

"" Fie. **0- DiMTUD to Eiplun Dnviiig Reactiaoa 

accomplbhed in one of Uiin, r«uu. Rod* 

three, ways. The first form was the so^^Ued radius, or distance, 
rod, which the shaft-driven car inherited from the chain^Iriveii form. 
In the chain drive, these 
rods were a necessity and 
served a double purpose; 
they kept the drivbg and 
driven sprockets the 
proper "dbtance" apart 
for correct chain driving 
(hence their name "dis- 
tance" rods), and they 
alsotransmitted thedrive 
back to the frame. On 
the shaft-driven car, the 
dbtance function is not 
needed, so they are called 
radius rods. As shown 
in Fig. 440, they transmit 
the drive forward to the frame, thus propelling the car in the direc- 
tion of the arrow.and they also keep the rear axle in its correct VQ».ti!QO-< 

Fia. 441. Uynit 



580 GA 


In liglitening and simplifying the ahaft-driveti rar, dedgners 
figured tiiat three members for the torque and driving reactions were 
too many; 30 a. design was worked out in wliich all tliree were combined 
into one, which is a form of tube surrounding the shaft. Tliis nisde 
the member light but strong, and simplified the whole rear end. As 
shown in Fig. 441, the tul>e has forked ends at the front, which are 
connected to the frame cross-member in such a way as to absorb the 
torque reaction and also to transmit the drive. The method has 
the further advantage of needing but one universal joint, and that 
at the front end. Furthennore. it gives a correct radius of rise and 
fall for the rear axle, since the center of the combined torque and drive 
nieml»er is also the centerof 
the universal joint in the 
driving shaft. In the form 
shown in Fig. 339 (radius 
rods not shown), the two 
di0erent centers will be 
mtteil, the torque rod giv- 
ing a greater radius than 
the shaft. Similarly, in 


cars it is gradually replacing all other forms. It has the advantages 
of minimum weight and fewer parts, and applies the driving force in a 
direct line to the frame, the same as the two radius rods do. On the 
other hand, it makes the springs serve a triple purpose, the demands 
on these for torque and drive transmission and absorption being such 
that the spring flexibility must be negligible, which makes the car ride 
hard. In addition, making the springs handle the three widely 
different actions puts additional stresses upon them, so that they are 
more likely to break. On the medium size and larger heavier cars, 
this construction is not gaining so rapidly. 


Classification. Rear axles may be divided into the following 
classes, distinguished according to the method of carrying the load and 
taking the drive: the form in which the axle carries both load 
and drive; the semi-floating form, carrying the drive and a small part 
of the load, the axle shafts not being removable without removing 
the wheels; three-quarter floating form, carrying the drive and a small 
part of the load, the latter being divided between the shaft and its 
housing, but with the shafts removable; seven-eighths floating form, 
carrying the drive but not the load, the arrangement of bearings to 
take the load being such that the wheel hubs do not rest wholly and 
solely upon the axle-casing end; the full floating form, in which the 
shaft does nothing but drive, and is removable at will without dis- 
turbing the wheel and wheel weight resting on the axle-casing end, 
which is prolonged for this purpose. 

The seven-eighths floating typp has been developed to meet the 
need which arose for a floating construction, in which the axle casing 
did not pass entirely through the wheel hubs. With the full floating 
form, any accident to the wheel, in which it was struck from the side, 
also damaged the casing, or tube, end. The result of this in nine 
cases out of ten was to make the removal of the wheel impossible, 
because the tube end, which projected through, was bent over. 
Moreover, repwing in sudi a situation called for a new axle casing 
-^ very expensive proposition. Consequently, the seven-eighthf* 
floating form was devdoped to present all the advantages of the 
full floating form, with tliis serious drawback eliminatefl by a rear- 
rangement of the parts whidi did not necemiBte prolonging the aidk 

.^ ^ 


Tfif^» fmorfrr- ^7ba///^\ 

ncipal Fonoft of K«ar Axle 

figures show how the three-quartc 


to lubricate, and yet which was down in the dust and dirt, so that 
lubrication was a great necessity. All these causes, coupled with the 
fact that the axle carried both load and drive, caused its disuse. 

Dropped Rear Axle of Full Floating Type. The dropped type 
of axle is not much used at present for cars of the shaft-driven type, 
the dropped part of the axte bed being used to hold the rearward- 
placed transmission. Fig. 444 shows a former American "type, in 

Fic. M4. R««r Coniti 

iD Embodying Dropped Type of R«r Aile 

which the weight of the car as well as the weight of the load is carried 
on the I-section drop-forged rear axle, while the drive is transmitted 
from the transmission by the usual shafts, which carry no load. The 
cut shows the complete assembly above and the dropped axle below. 
The round ends of the I-beam axle are hollow, carrying the driving 
shaft through the central hole and the wheels on bearings which 
fit over the outside. The wheels will revolve on the bearings, even 
if the inner shafts and transmission be removed from the chassis. 
Despite its manifold advantages, the expense of constructing 
an axle of this type — it is practically the same as that of two ordfc- 

I I 

tne dnve irom the differential t. 
joints. The inevitable loss due 
and to the two joints in each Ii 

fig. «4S. Typi™ 

UMng this form, although a few 
pany— have inserted a pair of joi 
rear wheels the same camber as ( 



i external notches, or jaws, to correspond with the teeth, but 
lally it is more of a claw type, the dri^-ing ends projecting inward 
m the point of attachment to the axle shaft. Another notable 
nt of difference — and one which makes a huge difference in the cost 
ies in the machining of these jaws, whether they are attached to the 
e or machined up with it in one piece. The latter is considered 
:ter and stronger in every way, but, as it is much more expensive, 
s used only on the best cars. 

The driving clutch takes various forms, one of which is shown 
the Studebaker axle. Fig. 445. In this type, the axle is a square 
I acting within a square hole in the hubs. In the small detail at 
: upper left-hand corner the letter A shows the square upon which 
; driving clutch is slipped. The spaces at the inner ends of this 
icate the clutches, or jaws, which mesh with corresponding slots 
the wheel hub and thus do the driving. 

iog Wheels Driven by Spur Ceu 

The dropped type of axles are neither all shaft-driven nor all 
lin driven. Fig. 446 shows one that is of the spur-gear driven 
ie. The dropped axle bed C is of tubular form, and the differ- 
ial case is dropped down on and slightly back of the rear axle, as 
"B. From this case, two shafts A A extend out to the sides, driv- 
the wheels through the medium of the spur gear D, which meshes 
h internal gears within the wheel hubs (not shown) . This type of 
r axle and drive is used on a number of the Fifth Avenue stages 
Sew York City. 

Internal-Qear Drive for Trucks. The spur-gear driven type 
t described is gaining rapidly for motor-truck use, because it has a 
nber of important advantages. Besides carrying the heavy load 
a member able to withstand any amount of overload, it materially 
itens the power-transmitting portion of the axle, which is enclosed 
1 therefore quiet. It is simple and inexpensive to construct and 
air. Fig. 447 shows a section through one of these axles, which is 


the driving clutches machined as an integral part, and that 
)\nng the two shafts for a few inches makes it possible to unbolt 

Fig. 41S. Elaniplc o[ Full Flun 

Fix 44!). Timki-n Kiill Fluating Ut:i 

remove the entire difFerential uijit- For tlie siikc uf compari- 
Fig. 45(» shows an axle whicli dilTers from Fig. 449 only In having 
i bevels substitute*! for the ordinary straight-tooth bevels. In 

design is seen in Fig. 431. Tl 

it dilTers fn)ni pre\iously destr 
floating t.\pe. Note the cncltis 
at its forward pIwI fur th^ i.n;.-= 


on the same drum, with operating shafts for both supported from the 
central part and ends of the axle housing. 

Rear-Axle Housings. Rear-axle housings are usually of pre3sed 
steel, although castings play a very important part and are some- 
times used alone and sometimes in combination with other castings or 
in combination with pressed steel. Aluminum, although not a depend- 
able metal, is used quite a good deal for the purpose of saving weight, 
as excess weight upon the rear axle is anything but. desirable. In 
one unusual but effective combination, the axle housing consists 
of two malleable-iron castings joined together by means of bolts at 
the centers, the brake drums being cast as a part of the tubes. While 
not usual, this is safe practice, for malleable iron is tough and will 
not break or splinter. It seldom is the case, however, that the axle 
casing is reduced to as few parts as are shown here. 

Welding Resorted To. Where the differential housing or brake 
drums are of malleable iron, cast steel, or even of pressed steel, and it 
is desired to unite them with the steel tubing forming the main part 
of the shaft housing, welding is now universally used. Formerly, 
it was good practice to make the casing a drive fit on the tube, riveting 
it in place, or else soldering it in place, making doubly sure by using 
rivets. Now, however, welding is resorted to, either the oxy- 
acetylene, electric, or some other process being used. 

In the axles shown in Figs. 449 and 450, it will be noted that 
the axle shell is of pressed steel, to which the spring seats are bolted, 
the remainder of the construction being formed by drawing. In Fig. 
448, however, the construction is such as to necessitate making the 
two halves longitudinally and then bolting or spot-welding them 
together. Being machined after they are fastened together, it makes 
as accurate a construction as the one-piece jobs. Figs. 449 and 450. 

Effect of Differentials on Rear Axles. A differential gear, 
sometimes called a balance, or compensating, gear, is a mechanism 
which allows one wheel to travel faster than the other and which 
at the same time gives a positive drive from the engine. This device 
is a necessity in order to allow the car to go around a curve properly, 
for in doing so the outer wheel must travel a greater distance than 
the inner one during the same interval of time. 

There are two forms of differential, the bevel type and the all-spur 
tj'pei'the latter differing from the former only in the use of spiw gears 


instead nf hcvrl fjciirs. The principle used in both is that a set of 
gears are ^o lieM tij>;etlier that when a resistance comes upon one 
part of the train nf gears the whole train will stop revolving around 
on a stafinnary axis anil revolve around another gear as an axis, the 
first gear, in the meantime, standing stationary, or practically so, 
according tn the amount of the resistance encountered. In the 
bcvol tyi)e, a pair of Iwvels are set horizontally. Between the bevels 
is a spiHtT with thn-e or fiiur arms, with a small bevel on the end erf 
each. These ■^uy,\\\ ln've!s mesh with the larger bevels at the sides 
and ordinarily stand still, ro- 
tating around on the arm o( 
the spider as an axis by virtue 
of the continued rotation of 
the two side gears in opposite 
directions. When one whed 
meets greater obstructions on 
the road than the other, thus 
holding it back, the stiaft I 
which drives that wheel lags 
behind the shaft driving tlic 


would permit the differential action and still allow the strengthening 
of the rear axle. Fig. 452 shows one solution of the problem, which 
has been worked out in such a way that the differential is moved 
forward into the driving shaft. The rear axle shafts are thus greatly 
strengthened, the designer being unhampered by the presence of the 
differential in the rear axle. In this design, one side gear of the bevel- 
gear differential is carried upon a shaft, and the other upon a tube 
around the shaft. Thoji, at the rear axle, two sets of bevel gears 
BiBz and AiA^ are used, Ai being driven by the main shaft, and driv- 
ing the right-hand shaft through the gear A2; while the other B^ is 
driven by the tube, and drives the left-hand shaft through the gear B^. 
In this case the axle shafts are made much larger than in the ordinary 
case, while the differential action is just the same. 

Improved Forms of Differential. Lately, much work has been 
done upon differentials to cause them to act as differentials should. 
The present form of differential acts according to the amount of 
resistance offered, but should act according to the distance traveled. 
When no resistance is offered, all the power is transmitted to that 
wheel, leaving the other stationary. This is just the opposite of the 
desired effect. If a differential Were constructed to work for distance 
only, then, in the case of a wheel on ice or other slippery surface which 
offered little or no resistance, both wheels would still be driven 
equally, and the power transmitted to the one not on the ice would 
pull the vehicle over it. 

One way in which the differential action might be corrected is 
by the use of helical gears and pinions instead of the usual bevel or 
spur gears. In the M & S forms, this construction is used. Fig. 453, 
showing the form constructed by Brown-Lipe-Chapin. In this form, 
each axle shaft carries a helical gear, and the differential spider carries 
two helical pinions with radial axes and four additional pinions, each 
of which meshes with one of the radial pinions and one of the gears 
on the axle shafts. On a turn, the outer wheel tends to run ahead 
of the inner and thus causes the nest of helical gears to revolve. All 
gears and pinions have a right-hand 45-degree tooth, so that one wheel 
may revolve the housing if the other is locked or held, but it is impos- 
sible to turn the free road wheel by pulling on the housing. The 
principle is the same as a worm steering gear in which the turning of 
the hand wheel may be transmitted to the front wheels, but the gear 



n tlie wheel end, because the worm If 

is usetl to advantage to prevent spinning on 

i> tu eliminate the skidding which the ordinary 

canniit l)e operated froi 
ihle. Tliis .IiHVr.>i.tiiil 
slippery ftroiirnl and als 

Aniitlier .si>niewliat similar device has but two pairs of helical 
pinions tri adiiition to tlie two hehcal gears on the shafts, the axes of 
eaeh pair beiii^' set at an angle to the others. Thus, each helical 
gear and ils pinion form an irreversible gear combination, so that 
niovemciit earnint be transmitted through either in the reverse direc- 
tion. Tliis form fulfills the same conditions as the Brown-Lipe- 
Cliapin M & H form, as the construction is such that no motion can be 



forward. On a turn, one wheel revolves faster than the other, say 
the right, and causes the right-hand ratchet to move faster than the 
differential housing, which can only go as fast as the other, or slow- 
moving, wheel. Then, the right-hand ratchet pushes the end of 
its pawl out of the tooth and gives it a free movement forward. As 
soon as the wheels revolve at equal speeds, the spring pushes it back. 
In the figure, the right-hand portion shows the original form in 

Poaaible Elimination of Differential. The whole modem tend- 
ency is toward differential elimination. In the cyclecars and small 
ears brought out in recent years, designers have been forced to get 

F!(. 154. Sketches Showing Constnictiou kod Op6TBtion of Gnrlm Dinnentlal 

along without it because of the demand for simplicity, light weight, 
and low price. This effect has been obtained by the use of a pair of 
driving belts, letting one slip more than the other; by the use of fric- 
tion transmissions; by simply dividing the rear axle and letting one 
side lag when there was resistance; by not dividing it and letting 
one wheel drag; and in other ways. The evident success of these 
small vehicles without a differential or any real substitute for one 
has set designers to thinking about this subject again, and some 
big cars without a differential, or with a more simple and less 
expensive substitute for it, may appear in the near future. 

Rear-Wheel Bearings. The bearings used on rear axles differ 
very littlo from tiiose used on front axles. All forms are used — plain 


liearinps. ball hciirinj;s, hiiW thrusta, roller bearings in both cylindrical 
itiid tapered typca, aiul all combinations of these. Thus, Figs. 445 
iinii 452 sliovv tlie exclusive and liberal use of ball bearings, while Fig. 
■iry] slinws all rnllers of two kinds and ball bearings for thrust bear- 
ings f^i'ly. 'i'lie two kiixls of roller bearings are the tapered roller and 
tlie flexible roller. Similarly, in Fig. 447, It will be noted that balls 
are nsnl n itli two kinds of rollers, straight solid rollers in the wheels 
ami flexible rollers in the dilTerential case. Figs, 449 and 450 show 
the exclusive use of the tapered roller type, a construction which is 
gaining gnniiid very rapidly, the same as in front axles, although, 
formerly, ball bcarinfts were most widely used. The materials 
employed are similar to those used for front axles, which have been 
l)revi(>usly described. Cases are made of all kinds of steel and iron — 
pressed, drawn, east, ete. — not to speak of crueihle steel, malleable 
iron, niaii);aiiese Imiiize, phosphor bronze, aluminum, aluminum 
alloys, and many eumbiiiations of these materials in twos and threes. 
Rear=Axle Lubrication. Rear-axle lubrication Is generally 
autoinutic in so far as the central bevel or other gears and the differ-, 
ential lionsiiiK are ciinccrned. The housing usually has a form of- 


necessary to remove the shaft alon^. In almost all cases, the axle 
must be jacked up. Many axles have a truss rod under the center, 
and this is in the way when jacking; however, this can be overcome. 
Make from heavy bar iron a U-shaped piece like that shown on 
top of the jack in Fig. 455, making the width of the slot just enough 
to admit the truss rod. The height, too, should be as little as will 
give contact with the under side of the axle housing. 

Substitvie for Jack. A good substitute for a jack is a form of 
hoist. Fig. 456, which will pick up the whole rear end of the car at 
once. This not only saves time and work, but holds the car level, 
while jacking one wheel does not. Moreover, with a rig of this kind, 
the car can be easily lifted so high that w;ork underneath it may be 
easily done. The usual hoisting blocks are very expensive, but the 
above hoist can be easily made by the ingenious repair man. This 
one was made from an old whiffletree with a chain attached at each 
end. For the lower ends of the chains, a pair of hooks are made 
sufficiently large to hook under and around the biggest frame to be 
handled. With the center of the whiffletree fastened to the hook of 
a block and tackle, the hoist is complete. By slinging the hooks 
under the side members of the frame at the rear, it is an easy matter 
to quickly lift that end of the chassis any distance desired. 

Workstand Equipment. Next to raising the rear axle, the most 
important thing is to support it in its elevated position. To leave it 
on jacks is not satisfactory, for they will not raise the frame high 
enough, and, furthermore, they are shaky and may easily let the whole 
rear end fall over, doing considerable damage. With the overhead 
hoist, the chains or ropes are in the way; so a stand is both a necessity 
and a convenience. In Fig. 457, several t\T)es of stands are shown. A 
is essentially a workstand, intended to hold the axle and part of the pro- 
peller shaft while repair work is being done thereon. It consists of 
a floor unit, or base, built in the form of an A, with six uprights let 
into it, preferably mortised and tenoned for greater strength and 
stiffness. Then, the four rear uprights are joined together for addi- 
tional stiffness and rigidity. If casters are added on the ends, the 
stand can be more conveniently handled around the shop. 

. The forms B are for more temporary work and consequently 
need not be so well or so elaborately made. The little stand C is a 
very handy type for all-around work. Stands of this kind with the * 



top surface j;roo\Td for the axle are excellent to place under cars 
wliicli liiive hi'vn put in storage for the winter. 

Till- staiiil Jl is, liki- A, a workstami pure and simple. In this, 
howi'vcr, the i!roppi.'d-(.'nd members allow supporting the axle at 


the dirt and, consequently, lessen the wear, and also lubricate the 
moving parts of the joints. A secondary function of the casings is to 
render these joints noiseless. If a car is not equipped with them, it is 
advisable for the owner to purchase them. 

The shape of these casings, when opened out flat, would be not 
unlike that of two bottles with their flat bottoms set together, that 
is, narrow at the top and bottom and n-ider at the middle. All along 
both edges are eyelets for the lacing. The enlarged center fits around 
the joint, while the small ends encircle the respective shafts. To apply 
the casing, one end is placed around the shaft on one side of the joint, 
and the lace started; then the lacing proceeds, gradually drawing 
the ends together and around the joint. When this has been com- 
pleted, and before the last end is closed, the whole is shoved back 
along the first shaft a little way, and the center portion half filled 
with a heavy grade of transmission grease. This done, the glove is 
pulled back into place, and the work of lacing completed around the 
second shaft. Both ends should be laced as tightly as possible, while 
the middle part should be loose. Sometimes these housings will 
become worn and make a very annoying chatter on the road, even 
when they are not sufficiently worn to warrant replacements. Under 
such circumstances, the offending member may be wound with tire 
tape held firmly in place in addition to its adhesive power by means of 
a hose clamp, as shown in Fig. 458. The coupling is held tightly 
enough to prevent the rattle and chatter, but not enough to interfere 
with its action. While not a handsome job, it does the business, 
stopping the noise effectively. 

Rear Axle. Rear axles do such hard work and must stand up 
under such a large portion of the load carried in the machine that 
they offer many chances for wear, adjustment, or replacement. 

Truss Rods. Truss rods hold the wheels in their correct ver- 
tical relation to the road surface and to one another. If, through wear 
or excessive loading, the axle sags so that the wheels tip in at the 
top, presenting a knock-kneed appearance, the truss rods must be 
tightened up. Usually, they are made with a turnbuckle set near one 
end, a locknut on each side preventing movement. The turnbuckle 
is threaded internally with a right-hand thread on one end and a left- 
hand thread on the other, so that a movement of the turnbuckle draws 
the two ends in toward one another, shortens the length of the rod. 


and thus piills the lower parts of the wheels toward one another, 
furrecting the tippiug at the top. 

To adjust a siiRgiiig axle, loosen !H>th loeknuts, remembering 
that one is riKht-hiindoH and the other left. Then, with the wheels 
jacked Hear of the ground, tighten the turnbuekle. A long square 
should be procured or made so that the wheel inehnations may be 
measured before and after. Placing the square on the ground or 
floor, which should he selected so as to be perfectly level, the turn- 
buckle should he moved until the tops appear to lean outward about 
i inch — some makers advise more. 

It should be borne in mind that even if the wheels and axle do 
not show the need of truss rod adjustment, if this rod be hK)se, it 
will become very noisy and rattle a great deal, as the rear axle sus- 
tains a great amount of 
jouncing. Moreover, this 
noise and rattle, if not 
taken up, wilt cause 
which cannot be 
taken up. 
. Dita^setubling Rear 

■1. " ja j.i P*w<i>*ne»^gfja _ 


then disconnect the spring bolts and jack up the chassis, using the 
spring for a support. Disconnect all torsion or radius rods and take 
off the grease boot around the universal joint in the driving shaft. 
Open tliis joint and disconnect the shaft. Take this off, and if the 
spring bolts have been removed, the rear axle will be free. Pull it 
out from under the chassis, and, if desired, further disassembling may 
be done more easily with the member clamped in a vice or laid on a 

Assembling. In assembling, almost the reverse of this process 
is followed, the parts going together in the opposite manner from 
that in which they were taken down. 

Noisy Bevel Gears. If the bevel gears in the rear axle are 
noisy, the time to fix them is when the axle is disassembled, as this 
is quite a job. In general, bevel gears make a noise because they 
are poorly cut, because they are not set correctly with relation to 
each other, or because the teeth have become cut, or chipped, by 
some foreign material which has been forced between them. 

In the first case, there is little the amateur can do bevond 
making the best possible adjustment and smoothing off any visible 
roughness. In the second case, it is simply a matter of setting one 
gear closer to ot farther from the other by means of the adjustment 
provided. When the axle is disassembled, and all parts are readily 
accessible, it will be found that there is a notched nut on either side 
of each of the bevels; there should be a wrench in the tool kit to fit 
this. It is then a simple matter to move one outward and the other 
inward in either pair, according to which needs the adjustment. 
In case the teeth have become chipped, the projections should be 
smoothed down with a fine file, while the sharp edges of the cuts 
should be dressed in the same manner. 

Packard Bevel Adjustment. Although strictly a transmission 
trouble, the older Packard cars have the transmission located on the 
rear axle, and this position made the adjustment of the bevel pinion 
difficult. For another thing, the shaft is very short and hard to hold. 
If the sliding gear on the shaft is meshed with the internal gear 
attached to the other end of the bevel-pinion unit, the latter will hold 
firmly, but there will still be a little play between the teeth. It is 
necessary to take this up, as otherwise the repair man would mistake 
this play for play in the bevel driving gear. It can be taken up as 


ms: Tiiki'im oM ^liilinp-gear unit from one of these transmissions, 
(ive uiR' nl' till' tt'ctli iiivi slide the gear into position for meshing 
I tilt- .spjRv Jit till' to]) between two teeth on the good gear. Drive 
n in wliere the tooth has been removed, and this will fix the two 
ily tiiKftlier witliout a particle of play. Then, by removing the 
IT from tlif (iill'iTL-ritial housing, the bevels can be tested for play. 
4."iil shdws thf transmission, bevel gears, and axle parts, also the 
- with tlie tooth removed and replaced by a pin, so that the whole 

vill 1; 


HriKiirfiir liruhii Spring Clija. The springs are held down on 
jixli's l)y nifaiis of spring clips, which are simply U-shaped bolts 



Limng Up Axles. In such a repair, however, the main thing 
to get the rear axle lined up correctly, which is not an easy job. 
lis may be done in the following manner: Get the car standing level 
a nice clean smooth floor; hold a large metal square with a plumb 
b hanging down over its short edge against the side of the frame, 
ove the square forward until the line touches the rear axle at 
me set distance out from the frame, say .3 inches, as shown in Fig, 
1. Then notice the distance this line is forward from the rear end 
the frame. In the sketch it is 16 inches. Transfer the square and 
jmb bob to the other side and repeat. Here it will be found that the 
itance from the rear end of the frame is either more or less. In the 
etch it is shown at 18 inches; so the difference, 2 inches, shows that 
e axle is out of alignment 
at much or half that, 1 
•h at each end. 

Thb axle is straightened 
loosening the spring bolts 
d pushing one side back 
e distance apparently 
eded, then fastening 
;htly and checking up. If 
t correct, try again, using 
dgment as to which side 
ould be moved. When 
lally satisfied that the rear 
le is square with the frame, 
is well to checis this against the center-to-center distance of the 
leels on each side. This is done by setting the front wheels exactly 
'aight and then measuring from the center of the right front to the 
nter of the right rear wheel. Then go over to the other side and 
;asure the center-to-center distance of the left wheels. The two 
les should agree exactly. If they do not, the rear axle prusumably 
eds more adjustment for squareness. 

Taking Out Bend in Axle. A simple method of repairing an axle 
lich has been bent, hut a method which is only temporary in that it 
not accurate enough to give a job which could be called final, is 
at indicated in Fig. 462. The axle was bent when the hub struck 
obstruction in the road, and it had to be straightened immediately. 

B Clipa Are RepUeed 
Motor World" 


A short IciiRth i>f 2 x 4 timber was cut to be a tight fit between the 
upper silk' iif tlit' liiib citp iind the roof beam. Then a jack under the 


■ and Plmub Bob 

mI' till' iniul was raised. As the jack raised the axle, 

tiii licld the hub down, enough pressure was exerted 

toforce the axle to give st the 

bend and return as nearly as 

possible to its original straight- 


ime, and was sure that the bevel gears were out f 
irere cutting each other. It was a low-pitched/ 
lot apparent at low speeds, but began to be hei 
liles an hour, and at times was very apparent, 
nnoyiiig, but tearing down the rear construction showw 

trouble; so the noise could not be at that point. Sometimfr 
he noise was definitely located in a pair of worn speedomet^h 
ears on the right end of the front axle. 

A good way to listen to rear axle hums out on the road is to>lay 
<ack over the rear end of the car, Fig. 463, with the head against 
he top of the seat and project- 
ig over slightly, and witlr the 
ands cupped in front of the 
ars, so as to catch every noise 
hat arises. The larger sketch 
hows the general scheme, the 
mall inset giving the method 
<f holding the hands. When 
he sound arising from the axle 
i a steady hum, the gears are 
II good condition and well 
djusted. If this sound is inter* 
upted occasionally by a sharper, 
.arsher note, it may be assumed 
hat there is a point in one 

1 the gears or on one of the 
hafts where things are not as they should be. By trying the car 
t starting, slowing down, running at various speeds, and coasting, 
his noise can be tied to something more definite, some fixed method 
f happening. In advance of actual repair work, including tearing 
own the whole axle, the gears can be adjusted. This can generally 
•e done from outside the axle casing and without a great deal of work, 
f the adjustment makes matters worse, it can be reversed, or if it 
nproves the situation, the adjusting can be continued, a little at a 
ime, until the noise gradually disappears. 

Checking Up Ford Axles. Many of ForrI bent rear axles 
an be fixed without taking down the whole construction. The prin- 
ipal point is to find out how much and which way the axle is bent. 

RcAT-Axle Koiiea 


Ay rfnidv'mjt tlic wliccl on the bent side ami placing the rig shown io 
I''ig. 4I>4 on the axie eiifl, the extent of the trouble can be indicated by 
the axle itself. The iron rod is long and stifT, with its outer end 
pointed, and is fastened permanently to an old Ford hub. The 
rig is placed on the axle and held by the axle nut, but without the 
key, as the axle lie free to turn inside the hub. With the pointed 
end of the rod re-;tirig on the floor and with high gear engaged, have 
some one turn the engine over slowly, so as to turn the axle shafi 
around. As it revolves, the hub will be moved, and the pointed end 
on the floor will indicate the extent of the bend. By marking the 
two extreme points and dividing the distance between them, the 
center is fmind. 'i'lien a rod can be used as a bar to bend the axle, 
until the pointed md end is exactly on the center mark. A little 
practice with this rig will 
enable a workman to 
straighten out a Ford rear 
axle in about the time it 
takes to tell it. 


Engine as a Brake. Although disregarded in any summary of 
brakes, the engine is the best brake possible, granting that the driver 
knows how to get the best results without doing any damage. The 
ordinary engine has a compression of from 60 pounds to 70 pounds per 
square inch, which is practically the pressure available when it is used 
as a brake. Since this is more pressure than any other type, or form, 
of brake will yield, its usefulness is self-evident. 

Qassification. Brakes are usually divided into two classes, 
differing mainly in location — the internal expanding and the e:(temal 
contracting. To these a third class should be added, because it par- 
takes of the nature of both, yet differs from each one. This is the 
railway type of brake with removable sho^s of metal, dilTering from 
the band t.vpe in that no attempt is made to cover the whole or even 
the greater part of the circular surface, but simply a smalt portion of it, 
against which a shoe is forced with a very high pressure. Both the 
other types are subject to division into other classes, the first into 
three subdivisions according to operating means, viz, cam, toggle, and 
scissors action. 

Brakes are generally divided according to their location, as shaft 
and rear axle. The shaft brake at one time virtually went out of use, 
but it is now being revived. The marked swing toward the unit 
power plant, together n-ithitssimpHfication, lightening, and elimina- 
tion tendencies, has produced a situation where a brake drum just 
back of the power and gear unit can be operated by the hand lever 
and a very short rod. In this way much weight and many parts are 
saved. An indirect advantage is that the brake is more accessible. 
With the worm drive, there is a marked tendency back to the shaft 
brake, particularly on motor trucks. Again, in the last few years, 
some work has been done with pneumatic, hydraulic, and electric 
forms of brake. With air under pressure for starting, and with water 
or electricity as needed for starting or for other purposes, it is a simple 
matter to utilize the same agency for braking, providing such use does 
not add too much complication and, at the same time, that it 
will give a superior method of snubbing the forward movement of the 
car. In case none of these advantages are realized, there will be no 
particular advantage in adding new forms of brake. 

External-Contracting Brakes. This class of brakes is divided 
□to but two types, viz, single- and double-acting. In the first, an 



enii uf a simple bumi is utithored at some external point, while the 
ntlier. or free end. is pulled. This results in the anchorage sustaining 
as much pull as is given to the of)erating end, that is, all pull is trans- 
mitted directly to the anchorage. This disadvantage has resulted 
ill this form hecomiMg nearly obsolete. 

Any brake of the true double-acting tvpe n-ill work equally utM 
acting forward or backward. The differential brake. Fig. 465, 
shows this clearly. The external band is hung from the main frame 
by means of a stout link which is free to turn. The band itself 
is of ver>' thin sheet steel, lined with some form of non-biimable belt- 
ing. The ends carry drop forgings, to which the operating levers are 
attacherl . These are so f*ha[)«*d that the pull is evenl,\' divided between 
the two sides of the band. Thb will be made apparent by conadering 
that a pull on the lever // will 
result in two motions, neither 
one complete, since each depends 
upon the other. First, there will 
(^ )) |l| be a motion of the upper band 

end B about the extremity of the 
lower one as a pivot, followed by 



of side-by-side internal brakes here must be attributed to superiority 
rather than to a desire to save in money or in parts. 

A considerable number of foreign cars, which are used in moun- 
tainous countries, show a method of cooling the brake drums by means 
of external cooling flanges. In some makes, even a water drip is 
provided for extremely hilly country. 

More modem practice shows no tendency to place all of the eggs 
in one basket, both forms of brake being employed together apd upon 
the same car, usually also upon the same brake drum, one set working 

Flc. we. BcDi Ci 

Bnkn lor Chun-Driven Ch 

upon the exterior, while the other works upon the inside. In Fig. 468, 
which shows the rear-axle brakes of the larger cars made by the 
Peerless Motor Car Company, this mechanism is plainly illustrated, 
both the brakes being shown, although the drum upon which they 
work has been removed. The parts are all named so as to be self- 
explanatory. In this construction, the inner, or expanding, band is 
operated by a cam. In the brake sets put out by the Timken Roller 
Bearing Company, of Detroit, Michigan, in connection with their bear- 
ings and axles, the toggle action is used, Fig. 469. The constructional 
drawings, Figs. 470 and 471, showing the brakes used on the Reo 
car, manufactured by the Reo Motor Car Company, of Lansing, 

! I 



In general, however, when both brakes are placed on the rear 
wheels, one external and of the contracting-band type, and the other 
internal and of the ejqjanding-shoe 
form, modem practice calls for a 
cam to operate the latter, oper- 
ating directly upon the ends of 
the two halves of the shoe, while 
)evers operate the band so as to 
get a double contracting motion. 

Some modern brakes may be 
seen in Figs. 472, 473, and 474. 
The first shows a system such as 
just described; the second shows 
a stiff metal shoe in both types; 
and the last a pair of shoes set 
side by side. In addition, the last- 
named includes a new thought in P'v- IW. Timken Daub1« Renr-Aile Bnke 

Fia. 4T0. BMtion 

that the brake shoes are floated on their supporting pins, as shon-n. 
This makes the bearing of the shoes certain when expanded against 
every portion of the drum, as the shoes can "float " until they fit exacdy. 



Double Brake Drum for Safety. A very important feature b 
pointed out in Fig. 472, namely, that of safety. Where hotli brake* 
work on a common drum, one insirle and the other outside, the con- 
tinuous use of the service brake (whether internal or external) heats 
lip the drum to such an extent that when an emergency arises calling 
for the application of the other brake it will not grip on the hot 
drum, being thoroughly heated itself. The double drum allows air 
circulation and constant cooling. 

Methods of Brake Operation. While it is generally thought that 
round iron rods are the nni\crsal means of brake operation, such is not 
the case. Many brakes on excellent cam are worked, as the illus- 
trations show, by means of cables. This idea is e\'en carrieii so far 

fiE^ i> 




wiseofr their n'spoctivc brake drums, the cable, being more flexible, 
gives less flanger nf tiiis. 

Tliis nietlKwl of operation seems to be gaining favor because of 
its siitiplicity. wliieli eliminates parts that add weight and gives 
immediate results when the parts are properly adjusted. The recent 
Xew York show rexcjiled a surprising number of small and medium 
iiWiC cars with eiihle-ojienited brakes. An inspection of these cars 
.showed a tiiceliaiiiriil < leanlJness which was lacking in many others of 
the same class on whieh an attempt was made to reduce braking rods 


important point, and one that should be looked after in the purchase 
of a new car. 

Brake Adjustments. In recent years much of the brake improve- 
ment has been that of making adjustments easier and of making the 
adjusting parts more accessible. This can be noted in such a case as 
the Locomobile, Fig. 472, where the special adjusting handle on the 
brake is carried to such a height as to make the turning of it an easy 
matter. Similarly, on the Pierce, Fig. 473, it will be noted that 
there is provision for increasing or decreasing the closeness of the 
shoes to the drum, which is easily accessible. 

Brake Lubrication. As for the actual brake surfaces, there is no 
such thing as lubrication. The surfaces should be kept as dry and 
clean as possible. If grease or oil gets out from the axle or other 
lubricated parts onto them, there is sure to be trouble. The operating 
rods and levers, however, should have fairly careful lubrication, for 
which purpose the best makers provide grease or oil cups at all vital 
points. If these be neglected, a connection may stick, so that when 
an emergency arises the brake will not act properly and an accident 
may result. 

Recent Developments. In the last few years, the only new 
ideas advanced in the way of brakes concern front-wheel braking 
and electric brakes. The former were used quite extensively abroad 
in 1913, but in 1914 they seemed to drop back; this, too, despite the 
fact that the Grand Prix race of the latter year showed in a marked 
manner the need for and special application of front-wheel brakes to 
racing and high-speed cars. 

Electric Brakes. A very eflBcient and compact brake, appli- 
cable with a small amount of work to any chassis having a storage 
battery, is the Hartford, shown in Fig. 476, while Fig. 477 shows the 
operating lever as it is placed beneath the steering wheel, and Fig. 478 
shows the wiring system. This brake consists, in substance, of a 
small reversible electric motor, to which a 100 to 1 worm reduction is 
attached. Attached to the drum is a cable, which is fastened to the 
usual brake equalizer. Turning the current into the motor from 
the storage battery rotates the drum, winds up the cable, and applies 
the brake. The complete outfit weighs but 35 pounds. The motor has 
a slipping clutch set to operate at 1000 pounds pull, at which it draws 
40 amperes of current from the battery for two-fifths of a seconc* 


In use. it replaces the emer- 
gency hand-operating lever, 
and is said to be able to putl 
a heavy car going 50 miles an 
liour down to less than 15 in 
a distance of less than 35 
feet. The pull is so great 
that the brake drums are 
oiled to prevent heating and 
possible seizing. 

Hydraulic Brakes. On 
the newer Knox tractors, a 
brake of very large size is 
made even more powerful by 
hjdraulic operation. This 
brake is shown in Fig. 479. 
At the left will be seen the 
il brake lever attached to 
a small piston in a chamber 
full of liquid. This chamber 



interaal-expanding type, are exceptional in size and work against 
steel drums attached directly to the wheel spokes. 

When the lever is drawn back in the usual manner, liquid is 
forced upward through the top passage to and through the pipes 
into the other cylinder, forcing the plunger to move, and, through the 
movement of the plunger, the brakes are applied. The return of the 
fluid is not shown, but it is assumed that this is through a simple pipe 
connection from the plunger cylinder to the hand-operated piston with 
a check valve. Should the initial movement of the lever fail to apply 
the brakes sufficiently, the driver can let the lever come forward and 
then pull it back again ; in so doing he will take into his lever cylinder 

more hquld from below without releasing the brakes. Then, when 
this extra quantity is forced through, the plunger is moved even 
farther forward, and the brakes applied more forcibly. The brakes 
are 20 inches in diameter by GJ inches wide. 

Vacuum Brakes. The latest development in the line of braking 
systems is the Prest-O-Lite vacuum brake. This brake consists of a 
controlling valve, a vacuum chamber, piping from the inlet manifold 
to the valve and thence to vacuum chamber,and a foot button or finger 
lever on the steering post to operate the valve and thus put the 
system into use. The rod in the vacuum chamber is connected up 
to the service brakes, the system thus taking the place of the usual 
pedal and foot operation. The chassis sketch. Fig. 480, shows this 



ill plan, .t Ix-ing the <-(iiitn)tlinK valve, BB the tubing from the inlet 
iiiaiiifoM to the i'iiiitn>llitj}; valve and from it to the vacuum chamber 
('. Tlic niii /' fn>m the cliamber will be seen connected to the 
s<Tvi(v-t)rjikc hmIs uml li'vcrs, 

III Fif:. tso the nictlnMl of operating the system is not shown, but 
in Fij,'. -IS! tlii' fnot Icvor can be seen with its connections. When 
this is prt'sscil, the (iintruilcr valve isopene<] and the engine, as it runs. 
draws jiir out of the chainber (' in back of the plunger, gradually 
(Tcalinn a viiciiiiiii. so that the plunger is forced to move forward to 
ciiinpcnsatc for this. As the plunger carries a tail rod projecting 
tliroufjli tlic cml of tlio cylinder, and as this rod is connected up to the 
lii'iikiii^: systi'in. but with a big leverage, the movement of the plunger 



possibilities of the new fonn make it more desirable as a service or 
running brake. 

\Vhatever advantages may develop in the use of these special 
tj^ies, it is certain that the next few years will see considerable 
improvement in braking, so that a greater force may be applied more 
quickly, and thus act to prevent a large part of the accidents for 
which automobile owners and drivers are now unjustly blamed. 

Draggii^ Brakes. Probably the fiist trouble in the way of 
brakes is that of dragging, that is, braking surface constantly in 

Fit- 481. Foot 

contact «ith the brake drum. This should not be the case, as springs 
are usually provided to hold the brake bands off the drums. Look for 
these springs and see if they are in good condition. One or both of 
the brake bands may be bent so that the band touches the drum at a 
single point. 

Another kind of dragging is that in which the brakes are adjusted 
too tightly — so tightly, in fa<'t. that they are working all the time. 
In operating the car, there will be a noticeable lack of power and 
speed, while the rear axle will heat constantly. This can be detected 
by raising^ either rear wheel or both by means of a jack, a quick 



lifting arranRciiieiit, ur a cranp, and then spinning the wheels. 11 
the brakes are drafigiiif;. they will nut turn freely. 

All that is needed to remedy this trouble is a better adjustment- 
For the new man, however, it is a nice little trick to adjust a piu'roT 
brakes so that they will take hold the instant the foot touches the 
pedal, that they will apply exactly the same pressure on th« turn 
wheels, and ,\-et will not run so loose as to rattle nor so tight as to drag. 

Dummy Brake Drum Useful. Wliere a great deal of brnkr 
work is to be done, particularly in a shop where the greater [wirt of 
the cars are of one miike, and the brakes all of one she, a great dwl 
of time and trouble can be saved by havinK a set of test drums. An 

ordinary brake dnii 
may be observed i: 

I with a section cut out so that the action inside 
all that is necessary, except that it sliould be 
As shown in Fig. 4S2, it is well to fit a pair (if 
handles to the brake dniin 
to Bit.sist in turning the 
drum when the adjustment 
is being maile. The reBl 
saving consists of the work 
which is saved in putting 



what causes the chattering. If the lining is cut away for about 30 

degrees on either side of a line drawn from cam to pivot pin, as shown 

in Fig. 483, it is said that this chattering will stop immediately. 

If further trouble of the 

same kind results, bevel off ' — 

the outside ends of the lining 

at the two 30-degree points. 

A number of sugges- 
tions in the way of possible 
brake troubles, particularly 
on the side-by-side form of 
internal-expanding brakes, 
are indicated in Fig. 484. 
This shows a semi-floating 
form of rear axle with the 
two sets of brakes and oper- 
ating shaft and levers. A 
number of suggestions are offere<l for this form, the most important 
of which is: "Renew worn brake lining and broken or loose rivets." 

When a brake lining is worn, the proceeding is much the same 
as with a clutch leather, with the exception that whereas the latter 

^-al^opBrnnnfl levers ^ c= TQawwMim bro)«linirjg 

IjTD^ ^ i^ilaoe wJc COM 
Fig. 484. Biake Tioubln Illuitratvd 

must have a curved shape, the former can be perfectly straight and 
flat. This simplifies the cutting; but most brake linings are made of 
special heatproof asbestos composition which is made in standard 
widths to fit all brakes, so the cutting of leather brake bands is not 
often necessary. 



Eliminating Noises. Many times the brake rods and levers 
wear just tnoiifjli to rattle and make a noise when running over 
rnugli rnads or cobblestone pavements, but hardlj' enougb to war- 
rant replaciTip tlieni. The replacement depends on the accuracy 
with which they work, the age and value of the car, and the attitude 
of the owner. In a case where the owner does not desire to replace 
rattling rods, the noise can be prevented by means of springs, winding 
with tape, string, etc. 

If tlif mil crusscs a frame cross-member or is near any other 
nu'lal jjurt, and ils lcnf;th or looseness at the ends is such that it can 
be shaken into contact there, a rattle 
wiU result at that point. This can 
(( '^')~^""~~-^^^ ^ remedied or rather deadened by 

wTapping one part or the other. For 
this pur[X)se, string or twine can be 
used as on a baseball bat or tennis 
racket liandle, winding it together 
closely so as to make a continuous 
cohering. Tire or similar tape may 
I be utilized. When this is dont'. 



difficulty of doing it by hand, makes the stretching device shown in 
Fig. 485 particularly valuable when much brake relining is to be done. 
This is a simple pulling clamp, which is attached to one end of the 
lining after the first end has been riveted in place. Then it is 
attached to the end of the shoe, and the nut tightened so as to stretch 
it. When it has been stretched sufficiently, the other rivets can be 
put in, or the shoe and band with the stretches in place can be laid 
aside for a while to stretch it fully before fastening. Obviously, this 
is applicable only to the internal- 
expanding form, but the hook 
and clamp can be used on any 
size or type of expanding brake 
Truing Brake Drums When 
both inside and outside surfaces 
of the brake drum are used it is 
highly important that both be 
true. Since they do not stay that 
way long, the repair shop should 
be equipped to true them up 
quickly, Atruingdcvicelsshonn 
in Fig. 486, with the wheel and 
brake drum in place on it One 
feature of the device is that brake 
drums need not be removed from 
the wheel. The device consists 
of a metal base having a strong 
and stiff wooden pier with a hori 
zontal ann the exact size of the 
axle end mounted on it. The 
wheels are placed on the arm and 
rest on it the same as on the axle when on the car. The tool is 
double, with two ends, one of which cuts the inside surface of the 
drum, while the other cuts the outer surface. At the center this tool 
is attached to a heavy casting, bored out to slide over the shaft and 
with a key fitted into a keyway in the shaft to prevent the tool from 
rotating. The end of the arm is threaded, and a large nut with two 
long arms is screwed up against the tool at the start, and then it is 
used to feed the latter across the work. 

Jig. 486, AppBTBtm lor Tr — „ __ 

Outside of Bnke Drum in Pliwe m 

Cmnay nfUiMtr World" 

F^^ 1 



Tills issiilijcit tna iHimbcr of modifications to fit it to the various 
sizes iiiiil siiiiiiL's ijf brakf drum. Another method is to use the lathe, 
proviih'il tlip shop is I'quippefi with a lathe large enough. By making 
a niandroi the same as the axle spindle and having a pair of dummy 
bearings to pliti'e on it, the brake drum can be slipped on to the 
mandrel, ami the wlmlf pnt right into the lathe. The surface, either 
internal or exterrLal or both, can then be trued Up exactly as if the 
drum were on the axle. 


Broadly speaking, there are but two kinds of wheels according 
to the service each is to Render, pleasure-car wheels and commercial- 
car wheels. The former may he further subdivided into wood, wire, 
and spring wheels; while the latter may be divided into wood, steel, 
and spring wheels. Smne of the commercial vehicle wheels are 
further divisible, as steel wheels into sheet steel and cast steel; 
wiioci into .siHiked and solid; and spring wheels into various tj-pes. 

Wheel Sizes. Wheels are used on automobiles, in combination 
the tins. In ali'nri! a resilient and yielding contact with the 


by 1^ inches deep. In both cases, A shows the 28-incb wheel and B 
shows the 40-inch wheel. Both instances, too, have been selected at 
random, and not so chosen as to favor either wheel. It would have 
been possible to so select the sizes of both obstruction and depression 
as to make out a stronger case. 

The height of the brick being 2 inches the wheel must rise that 
distance, whatever its diameter, but in the case of the 2S>incb wheel, 
this rise of 2 inches is largely relative to the wheel diameter being 
one-fourteenth, or 7 per cent. In the case of the larger wheel of 
40-inch diameter, the rise is again 2 inches, but it is now one- 
twentieth of the wheel diameter, or 5 per cent. In the case of the 

Fia. 487. Diacrun Showini AdnnUfe ot Luge Whnli io Pusing 

smaller wheel, the rise is distributed over a length of about 18.43 
inches from the moment when the fom-ard edge strikes the 
obstacle to the moment when the last part of the tire leaves the 
last edge of the brick. If this rise were evenly distributed over 
this distance, rising as an arc of a circle, its radius would be slightly 
over 22 inches. 

Considering the 40-inch wheel under the same circumstances, it 
performs the act of rising and falling 2 inches in the longer dbtance 
of about 21.5 inches, the radius of this rise being 38.75 inches. It is - 
obvious that the latter is a much easier rise than the former, the 
lift being distributed over a length 16 per cent greater. Similarly, 
with the descent from the high point to the surface of the road agam, 


this more gradual rise and fall convert the surmounting of the 
ribstiitlf frtim a sharp upward bump and downward jounce into an 
easy iimi not unjiii-asant swinging up and down. 

A drill) ''If'"' *i h()l(\ as illustrated by Fig. 488, shows the bene- 
ficial etVet't of the lar^e wheel better, perhaps, than does the rolling 
over a rise. A rut in the road 8 inches across, into which the two 
wheels <irop in passing, is shown. At A , the 28-inch wheel is seen to 
drop the considerable amount of yb inch, while at B the 40-inch 
wliecl drops but ^ inch into the same hole. Evidently the larger 
wheel has an advantage in so far as passing over obstacles or holes 
is concerned. 

A^aiii, on account of its larger radius, the arc of the larger 
wheel is flatter and has more length nf tread in contact with the 



Fif. 489. Con 

the felloe on which is the rim B, and R is the spoke which, at the hub 
end, tapers down to the wedge-shaped portion P. This matches up 
to the wedge-shaped ends of the other spokes, so that when the 
wheel is assembled they form a continuous rim around the central 
or hub hole. 

The spokes are held at 
their inner ends by metal 
plates and by through bolts, 
which are set at the joints 
between the spokes so as to 
pass equally through each 
spoke, as shown at D. Not 
only do these bolts hold the 
spokes firmly to the wheel, 
but they have an expand- 
ing, or wedging, action 
tending to make the center of 
the wheel very rigid. 

The outer end of the spoke has a shoulder E and a round part C, ■ 
which fits into a hole bored through the felloe. To prevent the 
felloe coming off after the spoke is in place, the spoke is expanded 
by means of a small wedge driven into it from the outside, as shown 
at F. In this way, the wheel is 
constructed from a series of com- 
ponents into a strong rigid unit. 

Such wheels wear in two 
places, at the inner and at the 
outer ends of the -spokes. The 
remedy in the latter case is to 
withdraw the small wedge and 
insert a larger one in its place. 
At the hub end, when wear occurs, 
this, too, must be taken up by 
means of wedges. Fig. 490 shows 
a method of doing this when the hub has no bolts at the 
joints. A false steel hub A is driven into the hub hole, after 
which wedges of steel are driven in between the wedge-shaped ends 
of the spokes. For slight cases of wear and squeaks, the wheel may 


be soaked in iviiter, which will cause it to swell, tiikJlig Up till of 
the space. 

There are various nnwlificationa of this, nearly all of them 
changing the hub end of the spoke. In tlie Schwartz wheel, a patented 
form, each spoke is made with a tongue on one side of the wedge^ 
shaped part and a groove on the other. In assembling the wheel, 
the tongue of each spoke fits into the groove of the spoke next to 
it, thus rendering the whole hub end of the wheel, when assembled, 
a, stronger unit, being .-itronger in two directions, one of them of 
more than ordinary value. In driving the tongue into the groAve. 
the wheel is'reuilered strong in a radial direction, but. when the wh«l 



these conical shapes is stronger to resist stresses from the side on 
which the point is located than would be the same number of spokes 
set flat. Hence, the staggered-spoke wheel has the ad\~antage over 
the ordinar>' tj'pe in that it has greater strength from both sides. 
In the figure, A is the iron hub, B the felloe, Ci the right-hand and 
Ct the left-hand spoke, and D the steel rim for the tire. This is a 
12-3poke wheel, 6 of the right>hand spokes Ct and 6 of the left-hand 
spokes Ct. The section shows how these pass alternately to the one 
»de or to the other, forming the strong cone shape. 

Another method of handling this problem in a somewhat similar 
manner is the use of double sets of spokes, the spokes, however, being 
in two different planes separated a considerable distance at the hub. 
Of a necessity using the same felloe, the outer ends must be m the 
same plane. Fig. 492 shows a drawing representing a section through 
the center line of the wheel, while Fig. 493 shows a photographic 
reproduction of it. 

In Figs'. 492 and 493, A represents the steel rim on the felloe 
F, the latter being of metal in this case, as is also the wheel so it 

almost every case, break practica 
sitating a new wheel instead of ne^ 
Wire Wheels. Many of the 
were inherited from its predecessoi 
- be mentioned the wire wheel. Pi 

Early Bicycle Modek. Fig. 4' 
wheel for automobiles, its construci 
ancestry. The spokes were set into 
and into the steel rim by means ol 
each end of the spoke resting on tl 
sleeves were screwed in and out to 
This tension was usually considen 


Following the failure of wire wheeb, there was a rapid change 
to wood wheels, which were almost universal for several years. 
Soon after this change was made, there was an increase in the size 
and power of automobiles, which, in turn, was followed by a demand 
for lessened weights. In the meantime, makers of wire wheels, 
knowing their faults, began to re-design in order to eliminate them. 
Their success is best evidenced abroad, where about one-half of the 
French and more than two- 
thirds of the English cars, 
in addition to over seven- 
eights of the racing cars 
in both countries, are now 
equipped with wire wheels. 

New Successful 
Designs. This result has 
been brought about by a 
realization of the previous ! 
defects and their elimina- 
tion. Thus, no more cast 
hubs are used, drawn or 
pressed steel of the highest 
quality and greatest 
strength being used instead. 
The spokes have been car- 
ried out farther apart at 
the hub, obtaining a higher 
cone and thus a stronger 
one. Spoke materials are 
better and stronger, besides being used in greater quantities, that 
is, larger spokes and larger numbers of spokes per wheel, in some 
cases a triple row of spokes being used in addition to the ordinary 
two rows. This additional row acts as a strengthener and stlffener 
much like the diagonal stays on a bridge. Fig. 495 shows a set of 
double-spoke wire, triple-spoke wire, and interchangeable wood 
wheels side by side for comparison, while in Fig, 496 is presented 
a recent triple-spoke front wheel in detail. 

In the former figure, the relative depths of the various cones 
and their corresponding strengths are made evident, being side by 


side. In this comparison, it will be noted that the new triple-spoke 
wheel has a much lonser outer cone than the (ionlilospokt wbocl, 
while, on the other haiul, the inner cone has been flattened. The 
triple spoke has ii greater depth, coiisideriiin; the set of tiicrn us ttfi 

additional cone, than ht 
In exaniininj: i 

the inner cone in the doublc-aet wliecU. 
the older donl)ie-siHikc fonn and the newer 
triple tj'po. it will he noted, also, how the 
wheel it-self, or rather the tire and rim, 
have been brought closer in to the point of 
attachment, thus rendering the, whole con- 
struction stronger and safer. In Fig, 495. 
it will be seen that (he center line o( 
hotli tire and rim passes midway lietween 
the inner anti outer ends of tlie hub on 
doubk-spoke wheels, while on the triple 
form it is e^'en with the inside end of the 
inner hub, being, in fact, farther in than 
ia the case with the wood wheel, One 
thing will lie noted in all these spokes, 
regardless of number, position, or inclios- 
rion. and thnt la that their 


All these arguments in favor of wire have been built up one by 
one, for much prejudice had to be removed. In spite of this, however, 
the wheel is slowly but surely building up a reputation and a long 
list of friends. Since, even now, England and the Continent continue 
to set the fashion in automobiles, it is not too much to expect to 
see wire-spoke wheels in common use in the United States in a few 
years. In fact, the dozen manufacturers 
offering this wheel in 1914, with ten more 
giving it as an option, have been increased 
to about forty who are fitting it regularly, 
with perhaps fifty or more offering it as an 
option in 1915. In fact, almost any car 
maker in the country will fit wire wheels 
for a slight additional charge. 

For 1917 some 20 odd makes 'of "cars 
are offered with wire wheels as regular 
equipment, and about 25 more offer this 
as an option without extra charge. As 
there are about 190 cars on the market, 
the former represents 10.5 per cent, and 
the latter 13.2 per cent of all makes; the 
two together total 23.7 per cent, or less 
than one-quarter. However, these figures 
do not quite indicate the relative popu- 
larity of wire wheels. 

Wire Wheels Muck Stronger. The 
increase in the use of wire wheels has 
been brought about by better designs; 
greater attention to the details of manu- 
facture, assembly, and use; but primarily 
by the greater strength which has been 

built into the wire wheel. One way in ^^ ^pj (;.„^ ouKirupie- 
which this has been done is by rearrange- ^'"'" "'" **""' 

ment of the spokes as, for instance, the triple-spoke form just 
described and shown in Fig. 469. Another and later form is the 
quadmple-spoke wheel as seen in Fig. 497. This is made and sold by 
the General Rim Company, Cleveland, Ohio, find is called the G-R-C 
wheel. As the sketdi indicates, It has all the features of demount- 

iibility, etc., nt other wire wheals, the notable differences being the 
spoke arrangement to gi\'e strength and the form of rim — a patentfd 
form to be described in detail later. 

By comparison with Fig. 496, it will be noted that a double 
triangular section is formed in the G-R-C, the inner spokes forming the 
inside of the hub and the outside of the hub forming one triangle, 
while the outer spokes from each form the other. In Fig. 49tt, it 
will be noted that there is but the one triangle and a straight row 
of spokes. 

Sheet-Steel Wheels. The sheet-steel wheel is really a form of 
wire-spoke wheel, with an infinite numlier of spokes joined together. 
It has many advantages, some of whioli might be mentioned fUt 
follows; strength, lightness, low first cost, low cost of maintenance, 
and cleanliness. To take them up in order, the strength of two sted 
plates set a few inches apart in a somewhat triangular form with 
the base toward the Hub and well attached at the ceiittr and at tile rim 
of the wheel, is self-evident. Aside from the natural strength of the 
steel plate.-i^far in excess of the wire spokes— or round wood spokes, 
there is the strength of the triangular form. A .strong connection at 



hub construction is much cheaper than the ordinary hub, for the 
reason that there are usually two parts where this construction 
requires but one, and this a very simple one needing little machining. 
Low maintenance cost is brought about by the rigidity of the whole 
construction; the few parts, which make few to replace or even to 
wear; the cheapness of these parts, when replacement is necessary; 
and the well-known strength and long life of sheet-steel plates. 

On the score of cleanliness, it may be said that this is one of 
the drawbacks of the wire-spoke wheel, cleaning between and around 

the spokes being very difficult, if not actually impossible. The 
large number of spokes makes the hub inside of the spokes impossible 
to clean, whereas, with the sheet-steel wheel, the cleaning consists 
in merely turning a hose on the sides of the wheel, the cleaning of 
the hub being entirely unnecessary. 

It will be noted, too, in this illustration that the wheel has 
con^derable spring, or should have, in a vertical direction. It is 
claimed for this tj-pe of wheel that this springiness is an added 
advantage as it allows the use of solid or cushion tires, and thus 


eliminates the troubleaome pneumatic tire witli its puncture and 
blowout possiljitities. For coraraercial-car use, all of the ad\antugi-s 
just mentioned are of ilmibte worth, for which reason the steel wheel 
is malting great strides forward on commercial cars, Wierc the 
springiness of the wheels is not so desirable as strength, the sbect- 
steel plates ma.\- \te replaced with either pressed- or cast-stcd side 
members on which htrcngtheiiiuiL! rib^ are furmerl. The aide» of the 
wheel have holes //// through them which are provided for venUIa- 
tion. to decrease the neight of the side sheets, and to lessen the wind 
resistance to the wheel when moving rapidly. In some steel wheels 
these holes are omitted; in others a larger number than the four 
shown here are used. Fig. 
499 gives a better idea of 
the general appearance of the 
wheel ready to use, being 
lettered the same as Fig. 498. 
The sixikes shown in Fig, -199 
are painted on the smooth 
exterior of the plates, but in 
other wheels these spokes are 



end and attached to a middle flange on the hub. The two outer 
members of themselves would be very springy and consequently 
very weak, being of very thin metal. The diagonal extra sheet stiffens 
the whole construction, besides adding 50 per cent to its side strength. 
This is also of thin metal, so the whole wheel retains some springiness. 
Parker Pressed-Steel Wheels. One fault with all the steel and 
sheet-steel wheels mentioned was that they did not resemble other 
wheels, consequently the people did not want them. Moreover, in 
many cases, their construction did not adapt them to the 
use of regular tires but, on the contrary, called for special 
and expensive forms. However, none of these drawbacks 
are present in a new form of pressed-steel wheel. Fig. 502. 
Upon close inspection it will be seen that this wheel has 
no felloe in the ordinar;' sense, the rim of the wheel form- 
ing the only felloe. In this respect, the wheel is an 
outgrowth of the former Healy demountable rim, the 

modem form being a combination of a demountable rim with steel 
spokes. This wheel is suitable for any car, the hollow steel spokes hav- 
ing great sustainiiig power. It is interchangeable with all ordinary 
wood artillery wheeb of the same size, and fit's between the usual hub 
flanges. The spoke portion is made as a pair of units, each forming 
half of all the spokes, the two being welded together. When finished 
in this manner, they have half the weight and more than twice the 
strength of the wood wheel, the greatest saving being at the rim, 
by the removal of from 60 to 100 pounds of metal and wood. 

This wheel takes the ordinary demountable rim directly upon 
the ends of the spokes, the one shown being the No. 1\ '«\w5&">a, *\s*j- 

Dy pressingout two or more sim[ 

Fi(. S03. General Appraraniv ii[ Pukcr H 

below the price ol wood wheels 

Requisites. On commercial 
to call for entirely different whf 
car wheels are notliine but nlea 


will make for low first cost and low cost of maintenance. A fourth 
desirable quality -might be added to these, the quality of being 
adaptable or adapted to the tires to be used. 

Wood Wheels. Taking Fig. 503 as an ordinary heavy vehicle 
wheel, let us see in what ways it fulfills or falls short of these require- 
ments. The spokes are large in both directions antt widened out at 
the felloe to give greater side 
strength. The felloe, which 
cannot be seen, may be judged 
as to size from the width and 
location of the dual tires, 
which would indicate great 
width and considerable thick- 
ness. This style of tire calls for 
a steel band shrunk over the 
felloe, while the heads of the i 
cross-bolts show how the tires 
were put on and held on. 
AH these make for great 
strength in both horizontal 
and vertical directions, and 
all parts except the spokes 
are simple to make, and even 
these are simple for the wheel 
manufacturer whose shop is 
rigged to make them. More- 
over, to fill the last require- ''«- =^' i>°'''"=-t- w™i Truct wh»i 
ment, the wheel is adaptable to this tire or to any one of a number of 
motor-truck tires which might be used. 

A slight variation from this is the double-spoke wheel, in which 
the spokes, in addition to being placed in double rows, are set so 
as to miss each other across the wheel, that is, each spoke of one 
row coming between two of the other. This placing allows the spokes 
to be made larger and stronger than in the ordinary' case, while the , 
double rows have the same strengthening effect as the tapering of 
spokes. The hub portion is assembled as two separate wheels, su 
that the work of assembling as well as of making the parts is slightly 
more than with the ordinary wheel. This is more than compensated 

nng with a con 

Fig. E04. -Whi. 

over the wood shoulder on each 
much like the ordinary steel tii 
Bolts are run through these rinirs 


It is said that one set of these tires was used for nine months, 
and at the end of that time they were still good for service. The 
tires reach clear to the hub, thus doing away with spokes and enabling 
the tires to be slipped over the hub and held in place by a removable 
flange bolted through the wood to the fixed flange on the opposite 
side of the hub. 

Cast-Steel Wheels. The heavier the service the more unsuit- 
able do wood wheels become, that is, wood-spoke wheels. For many 
five-ton trucks, practically all seven- and ten-ton trucks, and nearly 
nil tractors, the cast-steel wheel is used, either spoked or solid, the 
spokeil form being given the preference. Fig. 5()4 illustrates a spoked 
cast-steel wheel, fitted with a solid tire. The wheel is cast with ten 
heH\y ribbed spokes, a ribbed felloe, and a grooved-felloe surface, 
into which the tire is set. 

Miscellaneous Wheel Types. Steel. Steel wheels are gaining 
for heavy truck use, and a number of the better steel-casting firms 
are now getting into this work, with the result that better steel 
wheels are becoming available. 

Other constructions, such as steel and wood combination wheels 
with removable and replaceable spokes, and the like, are rapidly 
going out of existence. Truck work is unusually* severe, and it takes 
but a few weeks of actual use to show up any of the so-called freak 
wheels. The simplest seems to be the best, the only question at 
present being whether the material shall be wood or cast steel. 
Pressed steel may offer some opportunities in combination with 
welding, since good work has been done on pleasure-car wheels of 
this type. 

Spring Wheels wUh Longitudinal and Tangential Springs. Spring 
wheels for both pleasure cars and trucks have not proved to be all 
that was claimed for them. For pleasure-i'ar use thej- have gone 
out entirely; for truck use they are restricted to the smaller and 
lighter sizes, as the IJ- and 2-ton sizes driven at higli speeds in city 
work. On these sizes, one or two well-designal forms are giving 
good service- The cherished dream of putting the pneumatic tire 
out of business thniugH the medium of the spring wheel is still a dream. 
^ When longitudinal springs are used to do away with the alter- 
nations of stresses peculiar to the radially disposed springs, the 
appearance of the wheel is much altered, as Fig. 505 shows. This 

Fie. ^o. Seaton (; 

felloe, while those attached to tl 


oiisly moved forward. Since, however, the springs have a certain 
amount of stiiTness in their coils, and the wheels do not rise and fall 
relative to one another, except in so far as the twisting action is 
concerned, it follows that considerable shock must be transmitted . 
to the axle and thus to the body and its occupants. This wheel, 
therefore, while possessing strength to resist side stresses, does not 
give the smooth riding qualities so much desired. 

A wheel very similar in appearance and action but with the 
wood spokes eliminated has been used very extensively in the last 
few years by the express companies and other big users of motor 
trucks. Starting with a few of them on front wheels, they have 
saved tires and tire money 
to such an extent that 
the companies have added 
more and more. Next they 
were tried on rear wheels. 
Seeing the good results 
obtained by the big com- 
panies with these wheels, 
many smaller firms and 
tradesmen with only one 
or two trucks have adopted 
them. They take a small size 
solid tire in place of a very 
large pneumatic and are said 
to cut the tire cost from one- 
half up to two-thirds and more. While used mainly for vehicles carry- 
ing a 1-ton load, they have been tried successfully on 2-ton vehicles. 

It is in this class of service — the lighter vehicles for smaller firms 
— where every item of expense must be watched very carefully that 
the resilient wheel should show the best results. For heavy work, 
there seems little future for it. 

A form of wheel which comes somewhere between the two just 
mentioned, having some side strength and easy-riding qualities, while 
at the same time participating in part of the principles of both those 
described, is that shown in Fig. 506, which is a diagram showing the 
construction. This consists of spiral springs used not radially nor 
loogitudinidly, but tangentially. Moreover, the springs are not 

t lit: construction is si 
by muaiis of a water-tigli 
elements and thus lengtlio 
is lacking in all other whe 

Spring IV keels uitk F 
into a semicircular or spii 
There is a double reason f 
unless it be side strength. 
load, they are heavy, they 
continued; if made light, t) 
long drawn out. Morenvei 
of a single one puts the whe» 
l)ecomes verj- hea\y. 

While a number of flat-s 
lM>th here and abroad, theyh 
l)een pointe<l out. A French 
ugo had a pair of sets, each r 
one end attached to the hub t 
on the two sides were set in 
lomling would produi.^' an c 
to the hub. and that the op 
produtt' an absorption, one si 
of the other. In practice, ht 
gave a noisy, harcl-ridint' "4 

.-.*——.*- - ■ ■! I ■» ^»^1^^W'— Bl^^l 


itages of wood and, in addition, will so save the solid rubber tires that 
'mileages twice as great will be obtained. In this way; the tire cost 
will be cut in half, which will be sufficient within the ten-year life of 
the ordinary commercial car to warrant the purchase of the more 
expensive wheels. 

In the use of spring wheels, as well as of wire wheels for pleasure 
cars, the tire and rim situations are closely jnter-woven. No special 
form of wheel or rim can be successful which calls for a special tire in 
addition, because, in case of trouble on the road, in a small town, or 
an>'where outside of the big cities with large and varied sources of 
supply, the users would not be able to replace the tire. As will be 
pointed out later, the present rim-and-felloe situation, which might be 
described as chiaotic, must necessarily continue until the tire situation 
is cleared up. That done — and it is now in a fair way of being done 
soon — the rim situation also will be quickly cleared up, and, following, ' 
that of the wheel felloes. The natural fitness of the various forms and 
the unfitness of others to meet popular demand is rapidly clearing the 
way for the engineers and manufacturers who are attempting this 
standardization work. 


The removal and handling of wheels present probably the 
biggest problems in connection with them. True, broken wheels 
give the repair man a good deal to think about, but the quick accu- 
rate handling of jobs in which a broken wheel figures depends more 
upon possessing and knowing how to use certain equipment than 
anything else; the operations are so simple that they require no 
particular skill or knowledge. 

Wheel Pullers. In handling wheels a wheel puller of some form 
is generally a necessity; wheels are removed so seldom that they are 
likely to stick, and they get so much water and road dirt that there 
is good reason for expecting them to stick or to be rusted on. This 
means the application of force to remove the wheel. For this purpose, 
a wheel puller is needed, and a number of these have been illustrated 
and described previously, as gear pullers, steering-wheel pullers, 
etc. Any one of these devices which is large enough to grasp the spokes 
of the wheel and pull the latter outward and, at the same time, press 
firmly against the protruding axle shaft V\\\ Ao ^-^ ^«^ ^^. 


Sometimes, liowever, while owning a puller, a wheel breaks 
tliis is not available, or the repair man is 
the tn)ui>le, so that he dws not bring the 
puller with him. In sueh vases, 
the repair man must improvise 
some kind of apuller out of what 
he has on hand. Everyone carries 
II jack, so it is s)ife to assume tliat 
one of these will lie available a» 
well 03 some form of chain. If u 
chain of large size is not a\'ailat>1e, 
tire chains — particularly extra 
cross-Iinksi — may be fastened lo- 
(tether to answer the purpose. It 
chain is lacking, strong wire, wire 
cable, or, in a pinch, stout rope 
can be substituted. Attach the 
rope, wire, or chain to a pair of 
opposite spokes of the wheel, i 
jibout two feet of alack, Draw the chain 'M 


the ordinary jspck, that the combination of rope and jack does not 
always work to advantage. 

Similarly, the handling of heavy truck wheels gives much 
trouble even in the garage, for they are so big, heavy, and 
bulky that ordinarily two men are needed. One man can do 
the trick, however, with a platform or "dolly" like that shown 
in Fig. 508. This consists of a platform about 4 feet long by 
25 inches wide, fitted with casters at the four corners. Inside of the 
central part are placed a pair of wedges, one of which can be moved in 
or out by means of a crank handle. To use this, the wheel is jacked up 
a little over 2 inches, and the truck pushed under. Then the movable 
wedge is forced in against the tire so that the two wedges hold the 
wheel firmly and carry all of its weight. Then the casters are turned 
at right angles so that the platform and the wheel may be moved off 
together. The truck wheel is removed in the usual manner, that is, 
with the aid of the wheel puller or such other means as the garage 
equipment affords. The dolly also forms a convenient means of 
handling the wheel when it is put back on its axle. 


Kinds of Tires. Broadly, there are three general classes of tires: 
the solid, the pneumatic, and the combination or cushion. The solid 
tire needs little comment or discussion here — being solely for com- 
mercial cars — except in so far as it is used with some form of spring 
wheel, hub, or rim, as just described. Similarly, the cushion tire is 
mostly used for electric cars, its use following that of the solid tire. 


The pneumatic tire was originally developed for bicycle use and 
in the beginning many single-tube tires were used. All of the tires 
used today have two parts — an inner and an outer tube. 

Classification. Considering only the double-tube t^pes, there- 
fore, the pneumatic tire may be divided into three kinds: the Dunlop; 
the clincher; and various later forms brought out to go with the detach- 
able demountable rims; and similar devices. These latter vary 
widely in themselves, but all are modifications of the clincher form, 
with minor differences of the difference in rims. 

Dunlop. The Dimlop tire, so named after the Irish physician 
who invented and constructed the first piie\rDQ»X\e \xt^/\^\st<5k\is^ 


the tire when not inflated. This 
as soon as the tire was puncture 
a strong possibility of its being 
east after it had been stretched 

CUncher. To prevent this It 
and tire were brouglit out, each 
In the clincher tire, the fabric is b 
instead of being left straight out 
formed into a hump, or bead, wh 
formed in the rim. The latter di 
only in having this deep depres.siot 
510 shows this, in which the mirf 


the hard non-stretchable beading over the edge of the rim at one 
point. This done, the rest is easy. For this purpose many tools 
have been bought; some good, some bad, and some Indifferent. After 
a fashion, alF do the work, but that tool Is best which performs 
the operation most easily, most quickly, and with the least damage to 
the tire or rim. Fig. 511 shows a useful tool for this purpose. 

The wire wheel and demountable rims, both allow quick road 
changes of damaged tires, leaving the work of tire repair to be done 
at home in the garage with proper heat, light, tools, and materialn. 
This is rapidly bringing back into use the lower price clincher and 
straight-side tire forms, also' many new tools have made their 
removal or attachment a much easier and more simple task. 

Demounb^U Rim Types. Following the development of the 
clincher tire and rim until this fonn of tire was practically universal, 
came the first forms of the 
demountable rims, which 
consisted of a detachable 
edge or rim porflon, like the 
edge of the clincher rim in 
section. These were locked 
in place in various ways in 
the different forms, but the 
first demountable rims — they 
were called detachable rims 
— were made by cutting the clincher rims into two parts, one of them 
detachable. This allowed of slipping the tire on over the rim In a 
sidewise direction, and did away with the stretching and pulling 
necessary with the plain clincher. Since this was a tire which was 
detachable more quickly than the ordinarj- tire, it was given the name 
"Quick Detachable", and now both parts are known to the trade as 
the Q.D. tire and rim. 

yonSliid Treads. All of the later developments In the clincher 
tire have been along the line of stud<led or formed treads to prevent 
skidding. In this many different things have been tried. Fig. o\2 
sliows sections of many of the representati\e tires on the market. 
They are well known, and only the last three need any comment. 

Fig. 512 H shows the Kempshall (English) tire tread, which is 
built up of a series of circular button-shaped- depressions, or cups, 

wiiatever snape or form into non 

Kig. 511. Virions Typ« 

built-up structure, shaped like tt 
studded with steel rivets. When 
appearance of a leather-tread tire ^ 


advising higher pressures than those generally used, stating that 
the people do not pump their tires up hard enough to get the best 
results from the materials in the tires. There shoulcf really be no 
conSict of interests here as the owner should be as anxious to get his 
mileage out of the tires as the makers are to make good their 

Many makers have stated, as a result of their years of experience, 
that more tires wholly or partially fail or wear out from under- 
inflation than from any other one cause. It thus behooves the 
owner of a car to look well to the pressure in his tires, not occasionally 
but very frequently'. As the majority of gages attached to pumps 
in public garages are seriously in error, each motorist is advised to 
purchase his own gage — one of the pocket t^-pe which is simple and 
inexpensive — and carry it with him at ail times. 

In some cases, it will be found that pum)>ing the tires up to the 
makers' specified pressure will result in unusually hard riding, and 
the motorist must be his own judge as to whether he wants to ride 
more comfortably and get less wear out of his tires or to put up with 
the discomfort and get ever;' cent of wear out of them. In this 
matter, very few will choose the latter course. 

Use of Standard Pressure and Oversize Tires. There is really a 
different way out. If the tire pressure advised by the maker results 
in too hard riding for comfort while comfortable pressures result in 
too much wear, the motorist is advised to get large size tires. These 
on the same car will have a greater carrying capacity than the weight 
uf the car by a large margin. Just in the proportion of the tire 
capacity to the weight of the car will be the pressure recommended 
to the pressure utilized. 

A simple example will make this clear: Suppose, for instance, 
a car weighing 3850 pounds, equipped with 34- by 4-inch -tires, for 
which the makers claim a carrying capacity of 1 100 pounds per wheel 
and recommend a pressure of 95 pounds. If this pressure be too high 
for comfort, and lower pressures, say SO or 85 pounds, result in too 
.rapid wear, the motorist should use larger tires. For instance, a 
34- by 4i-inch tire is scheduled to carry 1300 pounds per tire, and the 
pressure recommended b 100 pounds. The car weight per tire is 
962 pounds, say 970. Changing to the larger tire gives a capacity 
of 1300 pounds per wheel, white the load is actually but 970. This 

n>u ifti UUUllllCU. inUS 

X ■■ 
The pressure, therefore, in i 
if this or any comfortable 
proper amount of tire wear ^ 
will be assured. 

However, this propositio 
to 34- by 41-inch tires, is on' 
possibly entirely new wheels, o 
diameter of the 34- by 4i-in( 
4-inch. In such a case as thi; 
to a still larger size, say 35- 
without disturbing the old rir 
for 34- by 4-inch. This sizi 
poundsat 100 pounds pressure 
and comfort will he obtained 

In general, the rule for O' 
1 inch larger in exterior diamf 
than the regular sizes, and an 
with the regular size on the sai 
sizes, as 30, 32, 34, etc., are co 
o(l<I-inch sizes, as 31, :J3,*3.'), . 
above is for Anu'ricnn or inch 


rims and pos^bly wheels. A larger nominal outside diameter will 
change the speed of the car and, if great, may be too much for the 
engine, calling for new gearing as well. The following tabular 
matter will be of interest, as it gives the changes in the metric 
size tires which can be made without altering either wheel or rim 
or changing the gearing. 

Possible Tire Changes 

Itnin: X 120 ir 


90 mm 

wheels can be altered to 7 


90 mm 

wheels cu 

be altered to 8 

and 8 


90 mm 

wheels CM 

be altered to 8 


90 mm 

wheels oar 

be altered to S 


90 mm 

wheels can 

be altered to ! 



wheels car 

be altered to 8 


105 mm 

wheels car 

be altered to 8 


105 mm 

wheels cai 

be altered to 


120 mm 

wheels cor 

be altered to 8 


120 mm 

wheels cat 

bealtcre.1 to 9 

935 n 

X 135 n 

These can be used without changing the gearing or the wheels, 
but to use different tires without changing rims is another matter. 
It will, therefore, be necessary to have another table of the various 
tires which are interchangeable on the same rim. Of the makes 
which are fairly international In character may be mentioned the 
German "Michelin" and the French "Continental", The following 
Michelin tires may be fitted to the same rim, the two tires on the 
same horizontal line being interchangeable in each case: 

Interchangeable HIchelin Tires 

mm. X 65 m 

m. and 700 m 

n, X 75 mm 

mm. X 65 m 

m. and 750 m 

n. X 75 mm 

mm. X 65 m 

n. and 800 m 

Ti. X 75 mm 

mm. X 65 m 

m. and 850 m 

n. X 75 mm 

mm. X 85 m 

m; and 710 m 

n. X 90 mm 

mm. X 85 m 

at. and 760 m 

n. X 90 mm 

mm. X 85 m 

n. and 810 m 

n, X ao mm 

mm. X 85 m 

ID. and 870 r>i 

n. X 00 mm 

The following tires of the Continental make are interchangeable 
on the same rims : 

920 X 120 and 920 X 125 

815 X 105 fit only 105 mm. rims 

Note. Although the 105 mm. ti 
cover can also be fitted on the same ri 
810 X 90 or 810 X 100 fit on the lOi 
875 X 105 fit on the 105 mm, rim 
910 X 90 or 910 X 100 fit on the 10( 
895 X 135, 935 X 135, and 1000 X V. 

Speed Changes Due to Chang& 
it might be well to say a few wc 
which a change in tire sizes will e 
being so serious as to impair the 
to be right in every particular. 1 
ence, the writer has found this t 
Using the old small wJieels and tir 
all grades easily and make the i 
a change to larger wheels and tii 
and gave much more trouble gen 
climber, so much so, in fact, that t 
and change the gearing so as to g 
engine again acted satisfactorily. 

Recent Tire Improvements. 
notable improvements in tires wh 

Tire Vahes. There have bt 



Inner Tvbes. Improvement has been made in inner tubes 
by the use of better and purer rubber in much thicker sections. 
Some of these have a partial fabric reinforcement; others are made 
and then turned inside out so that the tread portion ia under com- 
pression, thus resisting punctures or internal pressure. Other 
designs present a tube larger than the inside of the tire before infla- 
tion; this produces a truss formation of the rubber, which the air. 
pressure stiffens. ' 

Cord Tires. The real improvement of value, however, is the 
cord tire. One form of this is shown in partial section in Fig. 513. 
This shows graphically that the diflference between this tire and 

Pic. 513. Sntioi 

other forms is that the 4 to 6 or more la,\'er3 of fabric have been 
replaced by two layers of diagonally woven cord. This cord is 
continuous, rubber impregnated, rubber coveredj and, through its 
size, allows a great and very even tension. Lessening the amount 
and thickness of the fabric has given a greatee percentage of rubber 
in the tire; consequently, the cord tire is more resiUent. The advan~ 
tages claimed for it are: less power used in tire friction, which means 
more power available for speed and hill climbing; greater carrying: 
capacity in same size; saving of fuel; greater mileage per gallon of 
fuel; additional speed; quicker starting; easier steering, thus less 
driving fatigue; greater coasting ability; increased strength; and 
practical immunity from atone bruises owing to superior resiliency^ 

prupeny a plain ntn ; and th 

Plain Rims. The fom 
type, shown with tJie Djuiih 
endless band with two ed^ 
from coming off sidewiae w 
Xothing'like it is used todi 
of rim used with single-tub 

Clincher Rims. Clincl 
avoid the weaknesses of th 
and, Ijence, it bad an unum 
this tire remedied was the t 
to draw away from the rim 
clincher being made fairly 
the pocket, or groove, forme 

It is the depth of tins p 
size of the edge of the bead oi 
make the tire hard to i>ut oi 
the previous iliustrtftioiis of 

Quick-Detachable Tire 
of handling the clinchtT tire * 
detachable tire. This did n 
tire portion, the difference b 
jmrtion made in removable f< 
made integral with it. In som 



gered, rectangular ends into which these lugs fit. It requires force 
to spring the rings together so the lugs will go into the slots, but once 
in place, the natural springiness of the rings holds them firmly in 
place, and holds the tire as well. 

Figs. 514, 515, and 516 are given to show how this ring is put 
in place on a tire. Fig. 514 shows the beginning of the operation, 
and the instructions for the different steps will make them clear. 

Always start with left CDii of the ring! Lock this in thp rim as shown in 
Fig. 51-1, so that the end of the ring is flush with the slot provided for the aeeond 
end. A dowel pin is provided to register the ring in the proper place. This must 
always be correctly centered or the ring cannot be applied. This done, the balance 
of the ring can be forced over the flange of the rJrn, as shown in Fig. 515, with the 
exception of the locking end. By means of the tool, the lost locking end can be 

misod and forced overtherimintothercceBS provided for holding the same in poei- 
tioD preparatory to drawing the ends together, Fig. 510. showing the correct 
position of the tool. 

Then by entering the two points of the tool in the holes provided in the 
ring, the ends may be drawn together, as shown in Fig. 51G, and, with a slight 
additional leverage, the ends of the rings can be made flush. 

Before proceeding further, it should be stated that the object of 
the quick-detachable rim is the quick removal of the tire, in order 
to allow a quick repair or substitution of tiie inner tube. On the 
other hand, the object of the dcmnimtable, reinountable, removable, 
and other rims is the removal with the tire of the rim itself to allow 

year rim. This rim, as will h 
the idea being to remove the 
hook shape with a shght ridge 
This is on the fixed side, the 
against it as a stop. The tire 



which, in turn, pushes the locking ring tight against the outer 

curved part of the hooked rim. WTien in this locked position, 

the upper part of the flange 

hangs over the locking ring, 

so that it cannot rise vertically, 

the only manner in which it 

could come off. This rim is 

shown with a detachahle tire in 

position, but may be used with any standard clincher tire by the use 

of extra clincher flanges. Fig. 518 shows the rim with a set of these 

flanges in position, ready to take a standard clincher tire. 

Pi(. SIO. Univnsd 9.D, Rim No. S AiTBiijed (or CLncher and Dunlop Tirea 

Qvick- Detachable Number 2. Figs. 519 and 520 show the 
standard quick-detachable rim, now known as No. 2. This was 
adopted by the Association of Licensed Automobile Manufacturers 

as a standard and gnea the abo\e name. It has the feature of 
accommodating all regular clmcher, or Dunlop tires. In Fig, 519, it 
is ahowD at A ready for a clincher tire and at B ready for a Dunlop 
tire, the adaptation for the straight sides being shown. 

The two parts of Fig. 520 show sections of tires in place, making 
clear the exact use of this reversible flange. A shows a regular 
clincher tire in place, while S reveals the reversed flange in place with 
a Dunlop tire. Both Figs. 519 and 520 show the construction- of 


fT». S2l. fVflioi 


1 throuih Three 

q.D. UDivcruTltimii 

once it has been put iii place, 
flange a wider seat un tlie rim, 

As will be noted, the diffe; 
the old Goo<l.\t'ar and the I'ni 
ring and the shape of the lot 
universal rims l>oeause thev ma 

■i> i — ■ 

■ ■in i 



which has a modified Z-section, with a lip extending over the outer 
edge of the felloe band. The third section differs from the other two 
only in having the outer ring and locking rin'g combined into one, and 
the felloe band changed to suit this. This combination ring is held in 
place by means of a simple swinging latch, which is shown open and 
closed in Fig. 522. When opened, this permits raising the end of the 
ring, to which the shape of the felloe band offers no resistance. The 
whole inner ring is taken off, following around the circumference of 
the wheel, after which the tire is easily removed. 

Quick-Detachable Clincher Forms. To return to the plain 
clincher tire and the Q. D. rim, which allows of its ready removal. 





Fig. 523. Popular Fornis of 9.D. Clincher 
Rims, Shown in SeotionA 



vy/yy/y^///////////// ////////////// 

524. Throe of the Moet Widely Used 
Strtiight Side Q.D. Rims 

Fig. 523 shows four of the most prominent forms, these being indi- 
cated simply as flat sections of the rim, for the tire is the same in 
all cases. All these have the simple clincher edge on one side, with 
removable ring and locking device on the other. That at 1 has the 
same locking device shown at 2 in Fig. 521, the Z-shaped ring extend- 
ing over the edge of the band. That at 2 is practically the same as 
S in Fig. 521. The one seen at S is similar to that at 2 except for the 
detailed shape of the ring as well as the lock (not shown). The 
advantage of the form shown at ^ is that the outer ring is self-locking, 
that is, the shape of ring and band are such that when the former 



is in plaw tin.- tire itself lucks it. Its only disuHvantage is that 
it is harder to ii|)cnite than the other forms, yet despite this fact it 
lias hirn rcrnTniiifnilfd for general adoption as the only Q.D. clincher 
rim worth ooTitimiinK. 

Q.I). Ti/pr fur Siraighl Sides. To close the subject of straight 
sidt tires, the rims of tlie quick-detachable form now in use aside 
from tliiise already shtiwii are seen in Fig, 524. Here these are seen 
to be iiicntical with /, ^, and 4 of Fig. 523, except that the fixed 
side is arranged for a straight side instead of being made with a clinch. 
Here apiiii, the last form of self-locking type has been recommended 
as a stan.lard. 

Demountable Rims. All, or practically all. demountable rims 
come under niii.- i>i' two headings — those in which tlie tire can be 
detached on the wheel without demounting (if it is so desired) and 


Detroit; Baker; and others, the wedges carry a projecting lip, which 
makes it necessary to unscrew the nuts far enough to allow the 
removal of the wedge so as to 
pick this lip out from under 
the tire-carrying rim. In 
others, such as Empire, S.U. 
No. 1 and No. 2, the con- 
struction of the wedge and 
rim is such that loosening 
them frees the rim, the upper 
port of the wedge or clip 
swin^ng down to the bottom, 
position as soon as loosened, 
because of its heavier weight 
and the fact that there is no 
projecting edge to prevent it. 
While this latter construction 
makes a faster operating rim, 
it is an. open question as to 
whether it is as safe as the 
other form. These two con- 
structions are shown very 
plainly in Fig. 525, in which 
A is the Michelin with lipped 
wedges, and B the Empire 
vith plain wedges. 

In Pig. 526 is shown a 
pair of additional demount- 
ables, which are held by 
the local wedge method, the 
difference here being in the 
form of a wedge. Note that 1 
has a solid clincher rim and 
£ a straight side rim. The 
base, however, is the same 
for both and, as will be seen 
by examining this, has two 
. curves in its upper surface, the straight ^de rim fitting into the lower 


or bottom one, while the clincher form of rim fits into the uppci 
Note, also, that the wedges are the same for these two. Thi.* d 
the demountable 
of the rim prart 
universal in that 
owner can change 
clincher to straighi 
or nVp versa b\' s 
purchasing the exi 
of tire-carrying 
no change in the v 
or means of attach 
being necessary, 
this reason, the 
band shown under 
two rims has been 
gested as a stnndai 
n<.m.,uiir,i.ic-i^«...n„u- thr- Bolls dcmountables. 

!'n«-r.i.i uf CliiiiujiiKj liiikiT LiMtil Hedge Ti/)>e. In Fig. o 
shown tlic ItiikiT, which, as mentioned previously, is of tlie 
we<lge type of denn 
able, having a ti 
\crsely split rim w 
must be renmved I 
the wheel Jx-fore the 
can be taken off. 
haps this whole ac 
will be shown n 
clearly by the prciy 
sive series of views, F 
52S to 538, which si 
the various steps in 
moving and replacin 
tire and tul>e mounter 
a Bakef rim. the sanw 
" Pry "fl H"" is shown in section 

Ifiv hiilts except the two nearest the vi 
:e Iwisfcned by means of the special bi 

Fig. 520. First, all the ■ 
stem, one (in eithet avdv. 










Fla. G30. Third Baker Opention— Piiti 

until the wedges swing out and, down, as shown in Fig. 528. As 

mentioned, previoiwlj-, this means quite a little loosening, for the 

wedges have a long lip 

which projects under the 

tire-carrj'ing rim. When 

thia has been done, 'and 

as each one swings down 

out of the way, it is 

tightened just enough to 

prevent the wedges from 

swinging back. 

This done, the wheel 
b jacked up off the 
ground, as shown in Fig. 

529, and the point of the 
tire tool is inserted be- 
tween the felloe band 
and the rim carrying the 
tire at the point opposite the valve, where, it will be remembered, the 
wedges were loosened, and the rim will be almost free. By prying 
the tire-carrying rim out- 
ward and working around 
it toward the val\-e and 
back again, it will finally 
be loosened to a |x»int 
where, with the ^■alvc at 
the bottom, the rim and 
tire can be slipped off 
without lifting it. The 
extra tire and rim are 
now put in place. 

This is shown in Fig. 

530, where the re\erse of 
the operations shown in 
Fig. 529 and just de- 
scribed is followed, that 
is, the valve stem hole is revolved to the top, the valve stem inserted, 
the rim pressed into place all around, then the wheel is revolved until 

Fw. £32 Filth Opetatinn— SUrtmn to Tn 

the Rim oul of the Tirc-Heginning 

to Pty Short End 


Fig. 5^4. Seventh Operation— Prymg und' 


the Loom End of Rim 



the valve stem comes to the bottom, so that the two wedges 
which have not been loosened are nearest the ground. Then the jack 
is let down and removed, the whole weight of the wheel coming on 
the bottom point where the wedges are already tight, never having 
beeu loosened. 

This action is necessary as, with the weight on the other points 
where wedges are still loose, it would be necessary to' work against 
the car weight. At this point, as Fig. 531 shows, the nuts are loosened, 
using the special brace until the wedges can be inserted under the 
rim. This done, the nuts are tightened to hold them there. This 
tightening is continued until the little studs, or lips, in the rim rest 
on top of the outside edge of the felloe band, using the tire tool to 
force them in, if necessary. The new tire carried is supposed to be 
ready for use, that is, inflated to the proper pressure, so that these 
four actions complete the work of making a roadside change. 

When it is desired to repair the tire which has been removed, 
it is carried home on its rim just as taken off the car wheel, and the 
rim is removed from the casing as follows: Rim and tire are laid 
flat on the garage floor, as shown in Fig. 532, so that the outer end 
of the diagonal cut in the inside of the rim which is farthest from the 
valve stem is uppermost. An inside plate will be found on the rim 
which covers the two rivet heads on either side of the cut, with a 
central hole for the valve stem. This plate is called the anchor plate 
and must be removed. To do this, begin at the short end of the rim, 
which does not have the valve stem — as, in this position, it will be 
held in the long end — and insert the sharp end of the tire tool or a 
screwdriver under the bead or between the bead and the rim. 

These two actions, as shown in Fig. 533, bring the two short 
sides of the rim closer together and thus reduce the diameter. When 
the extreme end has been freed in this way, the operation is repeated 
some 5 or 6 inches farther around, that is, that much farther away 
from the slit. This done, a considerable portion of one end will be 
free. Then turn the rim and tire over so that this free part comes ^t 
the top instead of at the bottom and, standing on the part which is 
still tight, insert the tool between the rim and the entire tire. 

This frees the entire end, but, to make sure, the tool must be 
moved a little farther along so as to free more of it. When enough has 
beerC fceed to allow grasping it with both hands, as shown in Fig. 535, 

Fig. 5^16, the rim is laiil on the floor 
stem hole driiicil in it is raise*!, ai 
the beads art- piille<l into the rim, 
together somewhat tightlj' in order 
tice, it soon becomes an easy matt< 
part of the rim underneath the tin 
The inserted end of the rim 
end of the tire tool, as shown in 

tlie shape of the joint or cut in it 
proper place, but if it docs not, the 
pry it into place, or a hammer ca 
drive it in. 

The rim Wing fitted snugly i; 
ntatp is inserted, l-'itr !',:iK tn tirci--'>>f 



tire can be taken off the rim. However, not all rims are split on a 
diagonal as is this one, and Fig. 539 is presented to show this single 
feature on another rim, which otherwise is somewhat similar. Here 
the rim is split at right 
angles, having a plain thin 
rectangular plate A attached 
to the free end, or that which 
is removed first, while the 
other end has a swinging flat 
tapered plate with a cam- 
shaped end B, the action of 
which is to expand the rim 
to its fullest diameter and 
lock it there. In the top 
figure, it is locked — that is, 
the rim is expanded as ' it 
would be when in use and just 
after it had been removed for 
replacement. When the rim 
is to be remove<l from the 
tire, the latch B is swung out 
of the way, as shown in the 
lower figure, when the catch 
C which holds the two ends 
together can be opened hy 
lifting the tire with this 
portion at the bottom and 
then dropping it a couple of 
times. This done — usually 
this action will be accom- 
panied by the free end spring 
inside the fixed end — con- 
tinuation of the removal is an 
easy matter. The rim shown ,. t i. , 

'' Fm. MU. Serliunn throunh Two Ponulur 

is the Stanweld No. 20. "f D«no«nt«bic^u...n^h,>bi. /ti,«» 

Comparison of Continuous Holding Ring Tj/iw ivilh Local iVedge 
Type. To return to demountable-detachable rims, these ma\' and do 
include a number of those quick-<letachable forms previously shown 

«ii3 ucui^ Mtx-uiupiisnea oy ti 
band of a pair of wedge-shapt 
made and applied that it forn 
these wedges, while the other i 
ring is used with the flat ou) 

Fic. Ml. 

Dcmoimtoblc Tire 

Itim of Fimb 

difference, they have practicall 
band — that is, of the form show 
standard for all demountable-det 
example of the clamping-ring dc 
in Fig. 541, this being the Fires 


it became known that the Perlman rim patent had been adjudged 
basic by the courts, and that, on the strength of this decision, an 
injunction ^uid been issued against the Standard Welding Company, 
of Cleveland, Ohio, some few of whose rims have been previously 
described. Perlman's original patent was applied for on June 29, 
1906, and, in addition to this record, the fact was established that 
the owner had a Welch car which had traveled over 150,000 miles 
and on which were a set of the original rims. The case dragged 
through the courts and was discontinued some seven or eight years 
ago. Perlman persisted, however, although he had to revise and 
alter his application many times; the basic patents were finally 
allowed, and issued to him in February, 1913. This means, of course, 
that the patent will not expire until 
the year 1930. 

Perlman's locking elements and 
the principle involved are shown in 
Fig. 542, which is a section through 
the rim and felloe. In Perlman's suit, 
it was claimed that the wedge end of 
the bolt which was covered in his 
patent, included all wedge-operating 
rims, whether actuated from the 
center, as in Fig. 542, or from the side. 
This contention was supported by the ^*"''^"' ^'"''''"' "•"'" 

court, and negotiations are now in process between Perlman and man,^' 
manufacturers of the so-called local wedge tj-pe of rim. As this would 
appear to cover all the rims shown and described in Figs. 525 to 541 , 
inclusive, the influence of this decision upon the industry can be 
imagined. Moreover, the length of time which this basic patent ha.-! 
to run precludes the possibility of delaying action by prolongation 
of suits, as has been done in similar cases. |A notable example of 
^is is the case of the Selden automobile patents, which were fought 
on one ground or another o\'er a long period of years. 

Standard Sizes of Tires and Rims. As might have been noted 
in going over the above discussion of tires, plain rims, detachable 
rims, and, finally, demountable rims, all these different coustructicms 
require widely differing wheel sizes. It has been proposed to stand- 
ardize wbeeb, that is, the outside diameter of the felloe and with 

n "3, TypI,., ,.,||^, ^^j _ 




widely used demountable rims, depicting the band and rim in each 
case. The drawing should be read crosswise, each horizontal line 
showing the differences to be 

found in the makes mentioned in 
that particular tire cross-section 
size. Thus, the D sections show 
the differences for 3i-inch tires, 
E those for 4-inch tires, F those 
for 41- and 5-inch tires, and G 
those for h\- and 6-inch tires, 
rims for which are not produced 
by all makers. 

Other Removable Forms. 
Outside of the regular range of 
wood wheels and the standard 
tires for them, any different wheel 
calls for a different treatment. 
As has already been mentioned 
under the subject of Wire Wheels, 
few of these have anj-thing but a 
solid one-piece clincher rim; first, 
because the wheel itself is remov- 
able, thus making it as easy to 
change wheels as to change rims 
in the ordinary case; and second, 
to save weight and complication. 

DemounUAlefor Wire Wheels. 
However, demountable forms 
have been produced for wire 
wheels, one being shown in Figs. 
544 and 545. This is the G-R-C 
double Q.D, rim as the makers 
prefer to call it, in action a de- 
mountable-detachable form, the 
clincher rim being of the straight 
split type, in fact, a Stanweld 
No. 20. This is made with a 
double wedging surface on the 


dwid luOpmtMB 



outside and a single one ou the iiiuide. The latter cuntacta witli 
another on the false rim to which the wire spokes are attachw!, as dots 
also the inner wedging surface on the outer wedge. The outer wedg^ 
ing surface is made so as to come just above a fairly dpep slot in the 
false rim. In this is placed a ring with a double wedgt-shaped upper 
edge and a square lower edge. This ring is Split at one i>oiiit and 
locked in the highest position at the [mint diaiiietrically opposite. 

At the spht point, a pair of bent-arm levers, Kig. .54-4, arc 
connected to the two ends. Attached to-a middle i>oint of each of 
these is one end of an inverted L- 
fihaped member, llic center and 
up(»er part of whieli form h bear- 
ing for a locking stud, which is 
attached to one end of the rii^;. 
Above this is placed a nut. As 
will be noteil, this forms a toggle 
motion, th« action of which is 
111 expand tJie whole ring when 
tlic nut is screwed down and to 
oontracl it when the nut is 


up the inclme at the bottom of the cup, against the wedge on the 
underside of the rim, the amount of pressure exerted depending 
solely upon that applied to the bolt head. As the two wedge shapes 
oppose each other, this holds the rim as firmly as is possible. It 
will be noted that this construction does away altogether with the 
use of felloe bands or false rims used on other forms of rims or wKeels, 
thus saving much weight. Moreover, a great part of the weight 
is saved at the outside, where the flywheel effect of rapid rotation 
is thus lessened. Moreover, the absence of additional metal here 
would give the tire more chance to radiate its heat, and thus would 
preserve it better. This construction, considering its many advan- 
tages, should have a wide use. 

Similarly, with all demountable rims, the tendency is toward 
wider use, with which comes lower cost, as well as a better under- 
standing of their use, abuse, attachment, and detachment. With 
the standardization of tires to a few standard sizes, say 9 instead 
of 54, it will be only a few years before all kinds of rims, including 
demountables, will be standardized, at which time the latter will 
come into universal use. 


Composition and Manufacture. Tires consist of two parts, the 
tube and the shoe, or casing. The former is a plain ring of circular 
cross-section, made of pure rubber, containing an air valve, and is 
intended only to hold the air. The shoe, or casing, on the other 
hand, provides the wearing surface, protects the air container within 
from all road and other injuries, and constitutes or incorporates the 
method of fastening itself to thei wheel. In its construction are 
included fabric — preferably cotton — some pure rubber, and much 
rubber composition, the whole being baked into a complete unit by heat 
in the presence of sulphur, which acts somewhat as a flux for rubber. 

Considering a typical tire, there enters into its make-up, starting 
from the inside, six or seven strips of frictional fabric, that is, thin 
sheets of pure gum rubber rolled into intimate contact with each 
side of the cotton, making it really a rubber-coated material. Next, 
there is the so-called padding, which is more or less pure rubber, has 
a maximum thickness at the center of the tread, and tapers off to 
nothing at the sides, but usually carrying down to the beading. 

FiK. M7. Section Ihroiuili Ammbled; 



triangle resting on its base; around the wheel it is curv'ed to fit the rim'. 
The method of attaching the tire has a considerable influence on bead 
construction, since, in the clincher type of tire, in which the shoe must 
be stretched on over the rim, the bead must be extensible in order to 
insure easy mounting. In the quick-detachable and striight-side 
forms of tire there is no need for this stretching, so the bead can be 
made of stiff and rigid material as well as cut down somewhat in size. 

The straight-side or Dunlop type of tire is seldom made with 
much of any bead, the layers of fabric being carried straight down. 
A more modern form of tire has a 
pair of woven-wire cables incor- 
porated in the bead to m^e it 
stiffer and stronger, and this is 
said to ha\'e been very successful. 
As has been pointed out pre- 
viously, this could be done only 
with the quick-detachable form, 
not with the clincher type. 

In both the clincher and the 
quick-detachable forms, the bead 
holds the tire to the wheel by 
means of parts of the rim, which 
bear on it from above, as well as 
side wise, the internal pressure 
when the tire is inflated pressing 
it against these p>arts very firmly. 

In both the clincher and the quick-detachable forms, the bead 
holds the tire to the wheel by means of parts of the rim, which bear 
on it from above, as well as sidewise, the internal pressure when 
the tire is inflated pressing it against these parts very firmly. 

Tire Valves. In Fig. 547 there is shown a section through the 
tire valve but on a small scale. As this is a very important part 
and little understood, a larger view is shonTi in Fig. 54S. This is in 
two parts, A at the left showing the valve closed, and B at the right 
indicating the position of the various parts when the valve is open. 
Note that the lower part of the valve is hollow, so that air inside of 
the tire has access to the valve seat. Note that the valve is held 
down on this by the threaded portion above it. This valve seat 

which normally is held up agai 
spring, this being strong enough 
can pass between the two. Ti 
tightness. The spring must be 
together; and the surfaces mu:j 
held together, no air can get thr 

Actum of i'alre. The actii 
is pumped In, it passes down 
meets the projection, which it f 
the spring and, when there is ai 
internal air. As soon as this is ] 
if the external pressure is stoppe 
pump, the spring and the intc 
back into place, and no air can e 
of the pump, this is repeated, th< 
tire is filled. 

Leaky }'alrex. It will be nc 
projection, and \'a!ve seat, the ; 
valve tight. Thus, when a valvi 
part or parts of it are not in gc 
screwed down far enough, air ca 
so that leakage mH\- he remedied 1 
down into tlie stem. If the valve 


by taking out and cleaning the spring, also stretching it as much as 
possible. In general, however, the b^t plan of action with a 
troublesome tire valve is to screw it out and put in a new one. These 
can be bought for fifty cents a dozen, and every motorist should 
carry a dozen in a sealed envelope, also a combination valve tool, 
Ai'lien trouble arises with the valve, or a tire leaks down flat with 
no apparent cause, screw out the valve with the tool, screw 
in a new one, make sure it is down tight, and pump up again. Tlie 
few cents it will cost to throw away a valve, even if it should hap- 
pen to be good, will be more then compensated for by the time 
saved. Another point is that the whole valve assembly is so very 
small that it is difficult to handle. 

Washing tires often is a good practice, since water does them no 
harm, while all road and car oils and greases will be cleaned off, 
nearly all of these being injurious. Frequent washing will also serve 
to call the attention of the owner to minor defects while they are still 
small enough to be easily repaired, and thus they are prevented from 
spreading. When not in use, tires should be wrappe<l, so as to be 
covered from the light, and put away in a dry room in which the 
temperature is fairly constant the year round. They will not stand 
much sunliglit, nor many changes in temperature. Cold hardens 
the tires and causes the rubber to crack. Heat has a somewhat 
similar effect and also draws out its life and spring. 

In general, of all things to be cared for and repaired promptly-, 
no one thing is of more importance than the tires. If this rule is 
kept in mind, better satisfaction in the use of the car will result. 
So, too, with other repair work; If tools and appliances are made 
available and repairs made as soon as needed, the car will be better 
understood and give more satisfaction than if the opposite course 
be pursued. A few months of use of a car will do more to emphasize 
this than any amount of talk. Keep your car in good condition 
and you will reap the benefits of the little work you do upon it. 


Repair Equipment 

Vulcanization of Tires for Repair Man. In practically all of the 

following material the point of view is that of the profe^ional repair 

man, or of the garage man about to take up tire repairs, as dis- 



tinguished from that of the average owner or amateur lepamr. 
lesser tire injuries and their repairs are handled from ao ami! 
standpoint in another part of this work. 

Vulcanization, to the unitiated, sounds verj' mystmous, 
it really is nothing more or less than cooking, or curing, raw g 

rubber. Iii the processes of manufacture a tire is cooked, or cup 
all the component parts supposedly being united into one compi' 
whole. A tire is repaired preferably with raw gum or fabric prepai 
with raw gum, and, in orfler to unite this to the tire, vulcaniaat 
ir curing is necessarv- TWe c\wvu?„ in addition to uniting the pi 



properly, gives the proper strength, or wear-resisting qualities, which 
raw rubber lacks. 

Types of Vulcanizing Outfits. Shaler Vulcanizer. This curing, 
or cooking, is done by the application of heat, in a variety of ways. 
Generally, very small individual vulcanizers have a gasoline or 
alcohol cavity, holding just enough of the liquid so that when lighted 
and burned the correct temperature will be reached and held for the 
correct length of time. The larger units are operated by steam or 
electricity; the latter is preferred for its convenience, but the former is 
used by the majority of repair men. The source of heat is immaterial 
so long as the correct temperature is reached and maintained for 
the right lengh of lime. Too hot a vulcanizer will burn the rubberr 
while too low a temperature will not give a complete cure. 


For the average small repair man, the outfit shown in Fig. 549 
will do very nicely, at least to start with. This will handle a single 
casing or six tubes, or in a press of work, both simultaneously. This 
outfit is operated by gasoline, contained in the tank shown above 
at the right, but the same outfit can be had with pipe arrangements 
for connecting to a steam main, or for electric heating. In the case 
of either gasoline or steam, there is an automatic temperature con- 
trolling device which is a feature of the Shaler apparatus. As shown, 
casings are repaired by what is known as the "wrapped tread method", 
the repair being heated from both inside and outside at once, the 
outside being wrapped. Tubes are handled on the flat plate, shown 
in the middle of the framework, the size of which is 4^ by 30 inches, 
this being suflBcient, so the makers say, to handle six tubes at once. 

Haywood Vulcanizer, For larger work, a machine something 
like the Ha^'wood Master, shown in Fig. 550, is excellent. This is 
a self-contained unit, carrying its own gasoline tank, steam generator, 
and other parts. It handles four casings at once, while the tube 
plate G, 5 by 18 inches, is large enough for from three to four tubes, 
according to the allowance per tube made in the Shaler outfit. The 
separate vulcanizers are not designed for the same part of a casing, 
a side wall and bead vulcanizer being shown at /), a sectional vul- 
canizer for large sizes at E^ a sectional vulcanizer for small and 
medium sizes at F, and a side wall and bead vulcanizer for both 
clincher and straight-side tires at H, The gasoline tank is marked 
C, with vertical pipe in which is the gasoline cut-oflF valve K.- This 


and 3J-inch tires, and reliniDg mold for 4r, 4)-, 5-. and 5J-inch casings 
come with the device. 

This outfit with the extra molds, described but not shown, gives 
a very complete equipment for the small shop doing average 

Flc. 551. 

if Vuloaiiini Mold 

repairing. In fact, when a shop outgrows this type of equipment, 
it must specialize in tire work and purchase special equipment. 

Separate Casing Molds for Patch Worit. In the way of sepa- ■ 
rate molds for casings, an excellent example of the localized heat 
type is shown in Fig, 551 . By this is meant the form designed to 
vulcanize a small short section of a tire. The illustration shows 
five sections capable' of handling, respectively, 2i-, to 3-inch (motor- 
cycle), 2J- to 3-inch (small car), 3^- to 4-inch, 4J- to 5-inch, and 5^- to 
6-inch tires, thus covering the entire range. These molds have a 
special arrangement in that the heating portion is divided into three 
sections, into each of which steam can be admitted separately. This 
allows the use of one, two, or all the sections, according to the nature 
of the repair. 

In Fig. 552 is shown how it is 
possible, with this apparatus, to vul- 
canize the tread portion only by 
admitting steam solely to the larger 
bottom steam chamber around the 
tread, similarly, with the right-hand 
head or side wall or the left-hand bead 
or side wail. When a complete sec- 
tion is to be vulcanized, all sections 
are opened. The importance of this 
will be realized in a simple consideration of the fact that the tire itself 
has already been vulcanized and further heat is not only not good for 
it, but is distinctly bad, as H deteriorates the rubber. Where the heat 

FiK. 5S2. Section i 

"'""■" '■"'W«lfl,i„tl,,,,i„,, 


two casings at a time, and at least two, perhaps four, kettles full 
an hour, that is, from 40 to 75 ca»ngs a day, it becomes necessary 
to use a larger tj-pe of kettle, made in vertical types only. These 
consist simply of large round steel shells with hinged heads, into 

Fig. oij. hlislcr Llvt[i«1I> UuiWd Inudt Culni Form 

which the tires can be rolled and piled, after which steam is admitted to 
the whole interior. They vary in size from 36 inches inside diameter 
by 24 inches in length to 48 inches diameter by 40 inches in length. 

Inside Casing Forms. Another 
requisite of the tire specialist is an 
inside casing form, such as is shown 
in Fig. 555, or something similar. 
Many tire repairs are inside work, 
and even on those which are 
external, it is important to ha^'e an 
inside form against which the tire 
can be pressed and firmly held while 
vulcanizing. This particular form 
is heated by electricity, the wires 
being shown at the left; it is 14 
inches long and has an external 
shape to fit the inside of all casings. 

Side-Wall Vulcanizer. A shop doing a great deal of work can 
use to good advantage the side-wall vulcanizer shown in Fig. 556. 

iide-WiUl Vulcwum 



It has a single central member through which the steam passes, and 
aho has bolted-on w\t: plates, the insides of which are formed to suit 
either clincher or straight-side tires. In the figure, the side plates are 
not both in place, one being siiown on the work table below. The 
brace shown is used to remove the damping luits quickly and easily. 
This form is very useful on all side-wall or bead operations. It applie.i 
greaterpressurealong these parts of the tire than an air bag; it exactly 


wlieii putting on a complete new tread the mold must be used three 
times. The section, Fig. 558, is numbered as follows: casing, 2; 
inner mold, 1; new tread to be vulcanized, 3; vulcanizer proper, 4; 
clamp, 5; and steam space within which the beating is done, 6. 

Layouts of Equipment There are two wa\-s of installing an 
outfit somewhat like that just described, namelj', by the non-return 
system and by thp gravity- 
return system. 

Non-Return Layout. A 
typical installation according 
to the non-return system is 
-shown in Fig. 559. A steam 
trap must be placed in the 
system to remove the water 
and discharge it either into 
the sewer or into a tank so 
that it can be used again. 
In the figure there is shown a 
tube plate, a three-<ravity 
Sectional vulcanizer, two in- 
side molds, and a medium 
size kettle of the vertical tjpe 
placed in order from right 
to left. A pres.'iure-reducing 
valve is shown which permits 
the use of a higher pressure 
in the boiler, thus maintain- 
ing an even steady pressure 
on the vulcanizers regardless 
of fluctuations at the boiler. ompan^. tanapoin, una 

GraeUy- Return Laymd. When the coil steam-generator or flash 
type of boiler is used, the gravity-return system is utilized, this being 
a method of piping by means of which the condensed steam is returned 
to the coil heater to be used over again. This makes it necessary to 
set the apparatus so that the water of condensation will run back to 
the coil heater, which means that the pieces must be in a series, each 
successi\e one being set a little lower down to the boiler. Figs, 
500 and 5GI show a side view and plan view, respectively, of a small 



plant arranged on this plan. The outfit consists of the coil heater, 
which may be fitted to bum gas or gasoline, two inside molds, a large 
tube plate, and a three-cavity sectional vulcanizer. The outfit 

Flf. SW. ElcTBtioa of anvity-ltetura Vulc 

differs from Fig. 559 only in the absence of the kettle; on the other 
hand, the tube plate in Fig. 560 is larger. 

Small Tool Equipment. In addition to these larger units, the 
well equipped tire repair shop should have a considerable quantity 
of small tools, among the necessities being those shown in Fig. 562, 
At A is shown a flat hand roller and at ff a conca\'e roller. C shows 
an awl, or probe, which is used for opening air bubbles and sand blis- 
ters. /) is a smooth stitcher; F a rubber knife, of which two sizes are 
advisable, a large and a small; and G a lO-inch pair of shears for 

trimming inner tube holes, cutting sheet rubber, etc. // is a steel 
wire brush for roughing casings by hand; a preferable form is a 
rotary steel wire t\pe driven by power at high speed. / is a similar 

GASOLINE A UT< )M< )H I !.!■> 

H-iri- briisli fur roughing tubes; and J another bnisli with luiigei 
wires, also for roughing casings; K is a tread gage for markiiig 
casings to be retreadcd; and L & fabric knifo necessarj- in stepping 
down plies of fabric. M is a pair of plug pliers for placing patches 
inside of small tube repairs; iV ia a ctineiit brush for heavy casing 
cement, another very much smaller and lighter one— preferably of 
the camel's hair typi — being used for tube cement. is a hand 


open when working inside; a casing mandrel or tire last of east iron 
for holding a casing when making repairs; a tread roller for rolling 
down layers of raw stock evenly and quickly; a considerable amount 
of binding tape; thermometers; and such motor-driven brushes, 
scrapers, etc., as the quantity and quality of the work warrant. 

Materials. Each repair shop must carry such a supply of tire- 
repairing material as the nature and quantity of its business demands. 
Among other things may be mentioned: Tread stock, rebuilding 
fabric, single-friction fabric, cushion stock, breaker strips, single- 
cure tube stock, combination stock, cement, quick-cure cement, 
soapstone, valve bases, valve insides, valve caps, complete valves, 
vrdcanizing acid, various tube sections, tire tape, cementless patches, 
as well as many other tire accessories to sell. Many good tire-repair 
shops find a legitimate use for special tire-repairing preparations on 
the order of Tire-Doh. 

Inner Tube Repairs 

In general, all tire repairs come under one or more of the following 
headings; puncture; blowouts; partial rim cut or rim cut all around; 
and retreading or recovering, and relining. 

Simple Patches. Under the heading of punctures are handled 
all small holes, cuts, pinched tubes, or minor injuries. Generally, 
these can be repaired by putting on a patch by means of cement, 
or with cement and acid curing. When well done, this method is 
effective. This kind of a job seldom comes to the repair man, and, 
when it does, it is principally because the owner is too lazy to do the 
w^ork. About the only two cautions necessary are relative to clean- 
liness and* thoroughness. The tube and patch should be thoroughly 
cleaned. Again the patch should be large, well cemented, and the 
cement allowed to dry until just sticky enough to adhere properly. 
Many a simple patch of this kind has been known to last as long as the 
balance of the tube. 

Large Patches. ^ Cleaning the Hole. Whenever the hole or 
cut is large, it is recommended that the repair be given more serious 
attention and vulcanized. The ragged edges of the rubber should 
be trimmed smooth with the tube shears or knife, the minimum 
amount of rubber being cut away. The hole, however, should be 
made large enough to allow the insertion of an inside patch. Then 


thi' tube arounrf the holt" shoulri be clMtoeii thorniighly. This is best 
flnnc with a doth wet with gasoline, cleaTiing not only the outside 
!>ut the inside around tlie hole and at the edges. In order to make a 
gc»o<I job of this, it shoulit be gone over several times; the larger the 
liole the more care shouKl be used in cleaning around it. 

Preparing the Patch. Having the hole well cleaned ant! ready, 
these cleaned parts should be painted with two coats of vulcanizing 
cement, which is allowed to dry. This must be thoroughly, not partly, 
dry. Then the jiroper patch is selected, the smaller size being 
sufficient for small patches, while in the case of large repairs, the 
patch should be from 5 to 1 inch larger all around than the hole. 
If this is not a prepared patch, one side should be cemented just as 
tlic tube was previously. If a prepared patch is used, the semi- 
cured side should be jilaced in, tliat is, with tlie sticky or uncured 
side toward the tulie from the inside.' 

When the cement on the patch is just sticky euougli. it nhould be 
inserted and the tube pressed down against it all around, slowly 
and carefully so as to ^et good adhesion. Next the cavity about 
the inside patch is filled «ith gum or pure rubber, preferably in sheet 
form as it comes for this purpose. This is filled in until the surface 
k fliKl> It i< nrof*-rnbl-' tn »«• a liHlp vnlfBni^mcr rpmenf tn KnU 



a slight indentation from the point of a lead pencil. This is a good 
test to use at first, although after a short experience, the workman 
will be able to judge of the condition from the feeling, color, and 
general appearance of the patch. 

When the size of the plate is small, the tubes should be held up 
above it out of the way, partly to allow the full use of the plate 
surface, but also to keep the tubes from being damaged. 

Inserting New Section. Preparing the Tubes. In case th^ 
damage to the tube is too great to permit the use of a patch, for 
instance, in case a blowout makes a wide hole perhaps 7 inches 
or more long, in an othe^^'ise good tube, it is advisable to cut out 
the damaged section and insert a new section in its place. Somer 
times old tubes of the same size can be used for this, but, if not, 
sections can be purchased from the larger tire and rubber companies. 

\ \ 

Fig. 563. Sketch Showing Method of Iiucrting New Section in Innide Tube 

In the repair, proceed as follows: After cutting out the damaged 
section, bevel down the ends very carefully, using a mandrel to 
work on and a very sharp knife. As the appearance and, to a large 
extent, the value of the repair will depend upon these lx»vele<l ends, 
this should be done in a painstaking manner. • Next select the tube 
section and cut it to size, that is, from 5 to G inches longer than the 
section which was cut out and which this patch is replacing. This 
allows 2i to 3 inches for the splice at each end. ' Bevel the ends of 
the tube as well, and, after l>eveling ail four ends, roughen thern 
with a wire brush or sandpaper. 

Making the Splice. Having the tuixf and repair section i>evelwi 
and buffed, the ends to be joined should lie coated with one heavy 
or two light coats of acid-cure splicing cement. With the tul>e and 
patch property placed on the mandreLs — tulie on the male aiul patcli 
on the female — turn back the end to be repaired ntul tlie eiui to lie 



times very useful, as shown in Fig. 564. Here the pinched tube 
and l)l(iwout are indifatwl, the results of these on the inner tube 
and also their method of reiwir haviiif; just been described- These 
troubles together with punctures, leaky valves, and porous rubber 
in the tubes about cover the extent of iiu)er tube troubles. Because 
of their more complex construction, casings have more numerous 
and more varied troubles, which, consequently, are more difficult 
to repair. Tlie more common casing troubles are blisters, blowouts, 
rim cuts, and worn tread, the latter indicating the necessity for 
retreading. These will be described 
in order. 

Sand Blisters. The sand blister 
shown on the side of the tire. Fig, 5fJ4, 
is brought about by a small hole, such 
as an unfilled puncture hole, in com- 
bination with a portion of the tread 
coming loose on the easing near this 
hole. Particles of sand, roa<i dust, 
dirt, etc., enter, or are forced inf<i, 
this hole and move along the opening 
provided by the loose tread. S(H)n 
this becomes continuous and tlie 
amount of dirt within the break forces 
the surface rubber out in the form of a 
round knob known as a sand blister. 
This is cured by cutting open the 
blister with a sharp kn»fe on the side 
toward the rim and picking out all 
dirt within. When the rt'cess is 
thoroughly cleaned, the hole an<l the 
radial hole in the tire tread nearb\- 
should be filled with some form of 
self-curing rubl)er filler, a number of kinds of which are sold. The 
double benefit of this is to close the hole so that the trouble is not 
repeated and to keep out moisture which would ultimately loosen the 
entire tread. 

Blowouts. The blowout, which is perhaps the most important 
casing repair, may be made in two ways: the inside metho<l, in which 



1 { 


- 1 



Mclhod n[ Pni 



the whnle repair li* elTected on tbe inside; the combinatton insule 
ami outride mt-t)irNl. 

Itulde lit}Kiir MiHi'hU. Refer back to Kg. oG4 for tlie general 
tire coD.struction a.m\ t'l Fig. 505 fur this particular case, the iiiside 
of the tire is held open by means of tire hook.<) and the inside fabric 
layers or plies removed fwr a liberal distance on each side of the 
opening. As shown in Fig, 565, a Iraser amount of the second layer 
should be taken than of the first, and still less of the third and eaoli 
subsequent one. On .'^J-and 4-inch tires it is not advisable to remove 
more tlian two plies; on 4j-inch tires three, as shown; and on the larger 
sizes tour plies. The edge of each layer of fabric should be beveled 
down thin, as well as the material directly around the blowout. 


Ins^ide and Outside Method, In the inside and outside method, 
the material is removed from the outside, stepped down, and beveled 
in the same manner as for the method just described. Fig. 566 shows 
a tire with a medium size blowout, which has been stepped down 
for a sectionat repair, four plies having been removed. The rule for 
the number of plies to remove is about the same as before, except that 
in the larger sizes this should depend more on the nature of the injury. 
It should be noted, however, that in this case the plies have all been 
removed right down to and including the bead. This is done to give 
the new fabric a better hold and to make a neater job and one that 
will fit the rim better. Give the whole surface two good coats of 
vulcanizing cement, allowing it to dry thoroughly. 

Apply the same number of plies of building fabric as were 
removed, with the addition of chafing strips of light-weight fabric 
at the bead. Over this building fabric apply a thin sheet of cushion 
gum, slightly wider than the fabric breaker strip; then a thickness 
of fabrid breaker strip over this; and then over this fabric another 
sheet of gum, slightly narrower than the previous sheet. All this, 
however, should be built up separately and applied a^ a unit and 
not one at a time,, as described. These several plies should be well 
rolled together on the table. All edges should be carefully beveled off, 
especially the edges of the new gum where it meets the old, as it is 
likely to flow a little and leave a thin overlap which will soon pick 

No fabric is removed from the inside, but the hole is cleaned, its 
edges beveled, then filled with tread gum, and the inside reinforced 
with a small patch of building fabric; over this lay two plies of 
building fabric of considerable size. Now the whole casing is placed 
in a sectional mold, a surface plate applied to the outside, and heat 
applied both inside and outside. This will heat the tire clear through 
and make a good thorough job of curing. 

Rim-Cut Repair. Partial Cut. To repair a partial rim cut, 
one or two plies of the old fabric are removed, unless it is severe, 
when three plies may be taken off. This is removed right down 
clean as explained under Blowout Repairs, and the cement and new 
materials applied in the same way, with the omission of the fabric 
breaker strip. However, care should be used to carry all building 
fabric layers not only down around the bead to the toe but up on 

This it) ii)a<k- on tlic t;il>l<- iiiui tlit 
When compli'tcd, viiltaiiizc in a 
bag and lioati molds or ciicllcss aii 
wrap, and viilcanixc in hcator or 
not vulcanizt-tl, ami. with tiie ends 
rial loosened to show, may Iw seen i 
Retreading. Uctrcailinj; is a 
carefully, ni)t only Ix-eaiise of tlie 



tihould'be cleaned off right down to the carcass, and the latter cleaned 
thoroughly. As the rubber sticks, a rotary wire brush will be found 
useful and quick. However, this should be used carefully so as not to 
gouge the carcass. After buffing, the loose particles of rubber should 
Iw remo\ed with a whisk broom or dry piece of muslin. In this 
cleaning work the carcass should be kept clean and dry. Apply two 
foats of vulcanizing cement and allow both to drj-; the first should be 
a light coat to soak into the surface fabric; the second should be a 
heavy coat. 

Building Up the Tread. In building up the tread, it should 
not be made as heavy as the former tread, as the old worn and 
weakened carcass cannot carry as heavy a tread as when new. 
Furthermore, it takes longer to vulcanize a heavy tread and presents 
more opportunity for failure. In the building-up process, the pro- 
portioning of weiglits is important, and should be taken from the tab- 
ulation below, which represents ^ears of experience in tire repairing: 












•See Note 

3 plies 





•See Note 

4 plies 



•See Note 

4 plies 




4 plies 





•St* Note 

.i plips 





•Sec Note 






111 uf i-aK aftcc buffiug anil Tt 

This tread strip is built up on the table with exceeding care, 
all edges being rolled down carefully. When tlie strip has been 
propure<l anti the carcass is remlj' for it, one end should be centered 
on the careass, and then the balance of the strip applied an)un<l the 
circumference, being careful to center it all around, as the workman 
in Fig. 508 is doing. After it has been applieil all around, it should 


I St <if kelincr. 


11,\ , ;i]l air pot-kets opened with a sharp pointed 
tlic edges of the plies rolled down with the 
W'luii ready, vulcanize in a kettle, using an 
in- applied to a split curing-rim, and wrapped — 
i)jH-r] — all around. 

Many a casing which appears good on the out- 
i- iiii>itfe Ix-cause of fabric breaks on the insido 
■iiii be saved, or its life temporarily prolonged, 
ly tlie application of a reliner. By this is not 
iH-arjt the prepared canvas and fabric reliner 
\lii(Ii can be put in dry. but a regular built-up 
trip of building fabric, \Tilcanized in place so aa 
to be an integral 
part of the tire. 
For ordinary 
breaks, use a 
single ply of 
building fabric 


out, perhaps he could not do a better thing than to tak^ an old tire 
apart to see just how it is constructed. This will give a much more 
clear idea than any number of diagrams, sketches, or photographs. 

The tire repair man should remember, too, that this is no longer 
a game, but that, bj' means of scientific apparatus and the appli- 
cation of correct principles, it has been brought up to a high state 
of perfection; an expert can predict with reasonable accuracy what 
will happen in such and such a case, if this and that are not done. 
In short, the tire-repairing business within the last few years has 
been brought up to a stage where it, or any part of it, is a dependable 
operation. The tire repair man should handle all his work from 
this advanced point of view; it will pay the largest dividends in 
the long run. 


Q. What are the units comprising the final-drive group? 

A. Universal joints; driving shaft; final gear reduction; axle- 
shaft differential; axle enclosure; torque rod, or tube, or substitute 
tor this: radius rod, or tube, or substitute for this; brakes; wheels; and 
_ tires. 

Q. Why are these called the final-^rive group? 

A. Becausethey constitute the final drive of the car, beyond the 
power-producing unit, the engine; the connecting and disconnecting 
unit, the clutch; and the speed-changihg unit, the transmission. 

Q. What is the function of the universal joint? 

A. In the final-drive group, it is used to transmit power at an 
angle, as, from a horizontal-transmission shaft to an inclined-driving 

Q. How does it do this? 

A. The construction is such that the driving shaft is attached 
to one set of pins, while the driven shaft is attached to another, the. 
axes of these intersecting in a common point. As tlie driven shaft can 
turn about its pins in one plane and, with the complete joint, about the 
driving shaft pins in another, as well as combinations of the two, 
complete freedom, or universal movement, is assured. 

Q. What are the power losse£ in a universal? 

A. In a wellniesigned and fitted universal joint, working pratv 
tically at zero angle, there is no loss, but as the angle increases, the loss 
increases until at about 20 degrees, it may reach 2 or 3 oer cent. 

n. 1 lie engine levei vanes lit 
varies up and down through a coi 
rear end carries perhaps K.5 per cei 
road shocks because of this fact, 
front, or engine, end as quiet and 
These considerations necessitate a i 
ends, 30 that one can move free 
distances, while the other moves 
distances. In addition, the rear e 
away, so that freedom in a sidewiw 
way in which these necessities can 
universal joints. 

Q. What is a slip joint? 

A. One which will allow slidi 
within the other. Thus, under cer 
and fall of the rear end may mean a 
to and from the front portion. W 

Q. What is the usual form of 

A. Generally, this take^ the 
sqiiared-out housing, although son 
to give a slight universal action. 

Q. What is the modern form 

A. A thin flexible disc of steel 
with the drivinE shafts bolted to t 


Q. What is the biggest advantage of these to the repair man? 

A. They allow the removal of a driving shaft, or a unit on either 
side of such a joint much more quickly and easily, with less work, 
than any other form, similarly, in replacement after the repair is 
completed. In addition, they have no loose parts to be lost or mis- 
laid with consequent trouble and delay of the work. 


Q. What is the usual type of driving shaft? 

A. The usual driving shaft is of small diameter and solid. 
Cold rolled steel is used on the lower priced cars, but forged steel 
machined at the ends (at least) is used on the better cars. On many 
of the most expensive machines, the shaft is fairly intricate in shape 
and is machined all over after forging, sometimes ground after har- 

Q. What would be the advantage of a spring shaft? 

A. Being flexible, it would cushion the shocks so that none of 
these reached the engine. Such shocks as are induced by jerking 
the throttle wide open, or stepping on the accelerator pedal suddenly 
or, on the other hand, a sudden application of the brakes. 

Q. What is its real disadvantage? 

A. Being small, the owner of the car and the driver would 
always mistrust it, and would not feel free to drive as they would with 
a larger and more dependable shaft. 

Torque and Radius Rods 

Q. What is torque? 

A. Torque is turning effort, or force, applied to rotation, in the 
case of an automobile, to rotation of the driving shaft, and from it to 
the rear axle and wheels by means of the final reduction gears. 

Q. What is a torque rod? 

A. A rod, bar, or tube, provided to take, not the torque, but the 
equal opposite reaction from the torque application to the final drive. 

Q. What is the manifestation of this torque reaction? 

A. A tendency of the driving shaft and driving bevel gear to 
rotate up and around the bevel-driven gear in a counter-clockwise 

Q. How does the torque rod absorb this? ^1 

A. By extending this forward and attaching it to a frame cross 

A. In one of three w 
transmit it directly to the fra 
both torque and driving effor 
member, then to the main 
which are modified in attaci 

Q. Which is the best f 

A. The use of radius r 
stresses directly to the frame, 
the most expensive, the lieavii 

Q. Which is the most s 

A. The use of the spring 

also reduces tlic easy-riding q 

which should be flexible for i 

rigid in order to transmit torqi 

Q. Which is th? cheapef 

A. Undoubtedly the use 

it eliminates all ad<!itional ]>a 

fonn of springing end in place i 


Q. What are the usual m 


A. Fqf pleasure-car use, the spiral bevel form, and for motor 
trucks, the worm. 

Q. Why Is the spiral bevel popular on pleasure cars? 

A. Because of its many advantages. It Is just us simple as the 
straight l>evel, needs no additional parts, is more ({uiet, perhaps mora 
efficient, is less likely to cut or wear, can be removed as readily, and 
has other minor advantages. 

Q. Why is the worm popular for trucks? 

A. It has all the needed qualities; it is etRcient, silent, easy to 
handle, and allows bigger gear reductions than any other form. 
Furthermore, various gear reductions are interchangeable by changing 
other parts, and the worm lias other ad\'antag€s. 

Q. Why is the worm not used more on pleasure cars? 

A. Because it is not so well adaptai ti» high speeds of 50 to 60 
miles an hour and higher, which may be demanded, and because the 
large retiuction between engine and rear axle, which is its biggest 
advantage, is not needed on pleasure cars. 

Q. What are the three mostly used forms of rear axle? 

A. The full floating, semi-floating, and three-quarter floating. 

Q. Which is the best form? 

A. From an engineering standpoint, the full floating is undoubt- 
edly the best, but it is also the most complicated, with the largest 
number of parts, and the most expensi\'e to construct. 

Q. Which is the most simple form? 

A. The semi-floating form is the most simple, but it lacks 
advantages which the majority of car owners want. It is the cheapest 
to make, but is ma*Ie so thn>ugh the lack of these advantages. 

Q. Which is the compromise form? 

A. The three-quarter floating fonn seems to offer a maximum 
number of advantages with the minimum of disadvantages. It has 
practically alt the aiivantjvges of the full floatiag with less cost. It 
has all the advantages which the semi-floating lacks and costs but 
little more. 

Q. Which is the most popular form? 

A. The floating still has the greatest num)>er of makers, but the 
three-quarter form is rapidly gaining in popularity and, in another 
year, will displace the full floating as the most popular, both as to 
the number of makers and as to the actual number of cars. 

Q. What is a differential 

A. A inccliaiiioal (!cvi«T I 

(lifTcrciit (listaiut's wlicn tiimiii] 

Q. How is this done? 

A. By a>ml>iiiiiti(iiis, or u 

one-half being fixed t<» ench half 

of gears connet'ting the two. .' 

or stand still and have their g< 

transmitte<I all to one wheel, hal 

Q. What is the usual diffe 

A. The usual .iifferential 

spur gears, the bevel fonn being 

Q. What is undesirable in 

A. Present tiiffercntials hi 

for resistanee not distanct;. Thi 

want to slip, to slip on icy i>la('cs 

the diFercntial making a bail niai 

Q. If the differential work 

A. In such a cas<', since tt 

enci; in distance, and tlicre was 

place, the [Kiwer wonld he tran 

One would slip, hnt tt)c iitlicr m 

the iM>wer to pull tlic car olF the 


present differciitinls has never been explained, but can be readily 
proved by the simple process of building a car without a difTerentiaL 

Q. What forms of bearings are used in rear axles? 

A. Ail the different kinds of bearings are used in rear axles: 
plain bull, plain straight solid mller, striiight flexible roller, tapered 
roller, a few plain bnmze bearings, ball-tlirust forms, and others. 

Q. Which form is most popular? 

A, There is little choice between the two forms of roller and the 
ball bearing. In fact, the majority of axles use several <litferent forms 
of bearings; so it is difficult to compare the work of the various bearing 

Q. How can a broken spring clip be repaired? 

A, A good substitute for a spring clip can be made from two 
flat plates and four bolts to reach from one plate to the other. The 
purpose of the spring chp is to hold the spring to the axle; this combi- 
nation will do the same thing. 

Q. How would you line up a rear axle? 

A, With a try-square and plumb bobf workiiip downward from 
the main frame, determine the distance from the rear end of the frame 
to the back side of the rear axle, on each side i>f the car. Jf the two 
do not agree exactly, the axle is out of square by the difference, or by 
half this difference on each side. I>o(iseu the spring holts, set the axle 
correctly, tighten the Ixtlts, and check up the measurements again. 


Q. What are tlie two general t^es of brakes? 

A. The eontracting-band, which is an external brake, and the 
internal-expanding shoe. 

Q. How are these used? 

A. There is no set rule; some designers use only the internal- 
expanding form, claiming this is more powerful and dependable; 
others use only the band, claiming this Is cheaix'r to make and repair 
and just as good; still others take no side but use both forms. 

Q. Has there ever been any agreement in relation to brakes? 

* A. I'p to about a year ago, it was general practice to use the 

internal-expanding shoe brake for the emergency, nr hand, brake. 

This was the case whether the band form was usei! for the fnot, or 

running brake, iir another expan<liiig sIkk-. 

A. Except f«>r the teiiitei 
been l<K-ate<l as mudi as possthlt 
that this gave the m(jst direit 
braking forte. 

Q. How are brakes arrani 

A. When bwth brakes an- 
sharply dividefi into two camps, 
as a band form on the outside 
a smaller lighter drum, a more c 
expensive because the dnim is 
brakes side by side, making both 
inside a wide <lruni, claiming th 
and that the brakes are better pr 
l>eeause entirely enclosed, and tl 

Q. \\'hat is the electric bra 

A. A new de\ice which su 
motor for hand or foot applicatii 
action by a finger lever on the s 
through suitable resistanir, betwe 
the motor rotates a cable is wount 

Q. Is this a powerful form? 

A. Not only very powerful 
care must Iw o-uvl ii. ...."i.:--- ^^ 


ward again; this action soes not release the brakes but does apply 
more force, that is, it can be worked continuously until sufficient 
power is applied to stop the vehicle, a peculiarity of this particular 

Q. What is the vacuum brake? 

A. A new form which utilizes the suction of the engine to create 
a vacuum in a special braking cylinder, the movement of a piston in 
which applies the brake. The amount of action depends on the 
amount of suction, that is, regulated by the amount the valve is 
opened, and this is dependent upon the pressure applied to the finger 
lever or toe button, whichever is used. 


Q. What are the usual forms of pleasure-car wheels? 

A. The plain wood form and the wire wheel comprise 99 per 
cent of all pleasure-car wheels; the wood forms about three-quarters 
and the wire about one-quarter of the total. 

Q. What are the tendencies in wheel sizes? 

A. On small cars the tendency is toward larger and larger sizes, 
but on the larger heavier cars the tendency is away from the very large 
sizes of a few years ago. The latter tendency has been brought about 
by the standardization of tire sizes, and the elimination of 38s, 40s, 
and larger sizes formerly made. 

Q. What are the different forms of wire wheels? 

A. The double-spoke form, which is lacking in lateral strength; 
the triple-spoke; and the quadruple-spoke. The two latter make up 
in strength what the former double-spoke form lacked. Except for 
number of spokes, these do not look any different to the casual 

Q. What is the sheet-steel wheel? 

A. A form in which the whole wheel construction consists of a 
pair of sheet-steel members. These are given a slight taper, some- 
times have holes through them for ventilation and to make them 
lighter, and frequently are painted to resemble wood-spoke wheels. 
The steel sheets are made thin enough to be flexible. 

Q. What is the pressed-steel wheel? 

A. A newer form in which a simulation of one-half the entire 
wheel spokes, hub and all, is pressed out of thin sheet steel, and a pair 

yf. nnKn H the most po 

A. The wood form is stii 

vantages for heavy truck use, 

Q. What are the advanta 

A. Greater strength, pan 

ventilation am) removal of heat 

for the tire so that it holds its sh 

Q. What are the general d 

A. Pneumatic, cushion, an 

Q. What is the principle o 

A. The pneumatic tire has 

full of air, the tire gaining its res 

is HO wnstrurted as to have a c 

span! sf> that it gives a cushion ef 

solid mas-t o{ riibI»«T, its only give i 

Q. Is there a distinct tield 1 

A, Yes. Pneumatics are i 

ligliter trucks or delivery wagon; 

slow-spec<l electric pleasure cars a 

UHod only on the heavy trucks. 

Q. What is the big disadvai 

A. Its liahilitv to nnncfiir» 


Q. Describe the clincher type? 

A. This is made with a bead or hard portion at the base, which 
forms a projection around which the clincher rim fits. The rim has 
tlie shape of a flattened U with the en<is ciirlcti in, and the bends on 
tlie tire fit into these curle<I ends or chnches. 

Q. What is the advantage of this? 

A. The clinclitT form is held firmly on the rim, while the stiffness 
of the bead contributes more rigidity of form and permanence of 
shape to the whole tire. 

Q. Describe the straight-side form. 

A. This type of tire has no bead, the fabric forming the side 
walls being carried straight down to form the base without additional 
thickness of material. 

Q. What are the advantages of this? 

A. Its simplicity and lighter weight, with greater air space are 
the advantages of the straight-side form. In addition, in the newly 
standardized rim forms, the form of rim adapted to the straight-side 
tire is more sim[>le, lighter in weight, and lower in cost than any other. 
It has been found by experience that the holding power of the beads 
was unnecessary as the inflated tire could not come off the wheel 
whether it had a bead or not, since its diameter at the base could not 
be increased in any possible way sufficiently- to pass over the larger 
size rim. 

Q. What is an oversize tire? 

A, In the stnndanlization of tirci and rims, for each even tire 
size, which is called a standard, there is an oversize made which will tit 
on the same rim without any other clianftes. 

Q. What is the difference between standard and oversize tires? 

A. All standard tires are made in even inches of outside diam- 
eter, and all oversize tires are ma<le in <Mld inches of outside diameter, 
S(» that the rule for oversizes is this: An oversize is one inch larger in 
diameter and J inch larger in cross-section, that is, the Font size 
is 3() by .'ij. the oversize for this, according to the rule, is 31 by 4; an 
tt\-erage large car size is -Mi by 4^, the oversize for this is 37 by 5. 

Q. What are the general different rim forms? 

A. lliniH are generally divided into these forms; plain, which Is 

uMi Lfc ajijjiieu easily. 1 ne aem 
in combination with the others, t 
of the wheel by which the entire 
trouble, and then are replaced I 
beencarried for this form. 

Q. What are the advantage 

A. All roadside work is 

blowout occurs, the driver simpl 

and rim, and puts on the square ti 

lets down his car by means of tht 

damaged tire, is carried at the reai 

in the convenience and comfort ( 

station for that purpose. It savt 

when these are of the greatest va 

able rims, supplied on the car bj' 

operated with all these convenient 

Q. How are demountable 

A. Nearly all demountable^ 

separate bolts to press these into p 

the bolt and wedge are combined. 

Q. What is vulcanization? 

A. Vulcanization is the curi 


ual tire-curing mold the central space for the tire is surrounded by 
etal, with & hollow annular space outside of this into which the 
iam, which is generally used, is introduced. The heat from this 
mm penetrates the metal inside and vulcanizes the tire. 

Q. Are all vulcanizers operated by steam? 

A. Practically all the larger ones are, but many of the smaller 
rms of the portable type bum gasoline in the heating space, others 
e electric resistance coils. 

Q. What is the advantage to the private owner of a vulcanlzer? 

A. When a tire is cut badly, he can apply raw rubber as a patch 
repair, and then vulcanize this for the double purpose of curing 
.d of uniting it with the older part of the tire. In this way, tire life 
much prolonged at little expense. 

Q. Is vulcanization profitable as a business for a repair shop? 

A. It is said to be highly profitable, after suitable equipment 
a been purchased and a trade built up. It is said to be a more 
•ady and stable business than any other, for, as soon as an owner has 
en convinced of the value of vulcanization of tubes and casings, he 
11 bring in all his tire repairs. 

Q. What U a sand blister? 

A. A small opening in a casing, into which sand has entered and 
ntinues to enter until the outer surface is swelled up just like a 
ister. If neglected, this will ruin the casing. 

Q. How should a sand blister be cared for? 

A. By the immediate removal of the sand and the cleaning of 
e cavity, after which it should be filled with a tire-repairing cement 
tire-filling compound. The sand can be removed by cutting a small 
>le in the underside of the blister with a sharp penknife. 



Adjustable crankshafi llangcH. !<:; 
Adjutttliig annular bearings.... 421 

Adjusting clutch pedals :17S 

Adjusting fans 302 

Adjusting pumps 303 

Adjusting spring hangers 544 

Adjusting tension ot valves... 257 
Adjustment of air and gasoline 

supply 106 

Adjusinieni ot connecting-rod 

bparlngs 6!< 

Adjustment of nozzle I!)S 

Air i^oollng 300 

air Ja<^ketB 301 

blowers and fans 301 

flanges, or fins 300 

Internal cooling and scaveng- 
ing 301 

Air Jackets 301 

Alignment of front wheels r>03 

Antl-freezIng solutions 2^9 

Automatic gear-cutting machine 423 

Auxiliary air valve 107 

Axle bearings 501 


nail and Ball carburetor 151 

tlall tiearlngs 334,502 

Bearings Tfi. 330 

ball bearings 334 

bearing wear 77 

combined radial and i bi nsi 

bearings 337 

crankshaft jioundlng 7S 

handy wrench 80 

holding for bearings caps... 70 

plain bearings 331 

roller bearings 332 

test tor tightness 78 

Becker gear-cutting machine. . . 424 

Bending oil pipes .32!i 

Bennett carburelor 185 

Bent needle-valve stem .... I9G 


Bevel gears 42K 

Bevel type of friction disc 402 

BUgram gear-ulanlng niacbine. 4ZT 

Blowers and fans 301 

Blowouts in tire repair 6»3 

Brake adjustments '. . . . 613 

Brake lubrication 613 

Brakes 604 

brake adjustments 613 

brake lubrication 613 

brake troubles and repairs.. 617 

elassiflcat ion 605 

double brake drum for safely 610 

electric 613 

external-contracting 605 

function 604 

hydraulic 614 

Internal-expanding 60G 

methods ot brake operation. GtO 
recent developments 613 

Brown and Sbarpe gear-cutting 
machine 423 

Browne.Branford carburetor.. . 132 

Browne carburetor — one adjust- 
ment 130 

Bushing removers 56 


('able iind rope drives 402 

Cadillac carburelor 1T4 

Cams 232 

Can! Ilever ; , . . . 534 

Carburetor 9!) 

rlasBlflcatlon 101 

effect ot heavier fuels W 

floats lOS 

function of ihe carburelor.. 9ti 

needle valves 104 

throttle valves 103 

Carburetor adjustment, general 19T 

Carburetor and carburetlon, . . R9 
Carburetor operation and ad- 

lustm«DtB 112 

Hiir oiiTallon Hiid 
ifiiicnia ii'Oinliiiiedi 
iiiKl BhII ciirlJiircU.r 


i-iniillai* railiiirpior lU 

larlmreiorsi on Kord i^ars 122 

Curtpr car In I ret HI' . . ,,,.... 170 

lli'iiiif bSk gpneratiir 193 

KilwardK ciirhnrplnr- 137 

forelRTi kerosfiii' ciirljiiii'iors 181 

"H & S' diiiilpx carliuielor. 189 

Hoilvy carhiirplni- , , ,12i>. 180 

.loliiisoD .iii-l'iiieUiT 167 

I'Brburetor Iroiiblps and reinp- 
dies (conlinuedl 
emalleBt detail iintxtrlani. . . 2 
throttle loose on shaft 1 

Carter carburetor 1 

t-steel wheels 8 

Chain drive for camshatts. .. . 2 

Changing tires G 

Interchangeable Continental 

tires fl 

Interchangeable .M i c hcltn 


possible tire cbBngeE. , . .. , . G 
aiieed changes due to changed 

CharacterisllcE o( good oils. .- . 3 
Characlerlsllce of pislon rings 

chassla group 5 

characteristics of parts 5 

frames 5 

shoclt absorbers 5 

springs S 

Checking up cylinder bore... 


Commercial-car wheels (con- 
modern status of spring 

wheel 642 

requisites 636 

wheel troubles and repairs.. 643 

wood 637 

Commercial vehicles, construc- 
tion of frames 523 

Composition and manufacture 

of tires 673 

Cone clutch 352 

Connecting-rod bearings 63 

Connecting-rod troubles and re- 
pairs 65 

Connecting rods 61 

Contraoting-band clutch 364 

Cooling systems 286 

air cooling 300 

cooling troubles and adjust- 
ments 302 

water cooling 286 

Cooling troubles and adjust- 
ments 302 

Cork inserts 375 

Oankcase arms and engine 

supports 87 

Crankcase construction 84 

Crankcase materials 87 

Crankcase oil 329 

Crankcase troubles and reme- 
dies 88 

Crankcases 84 

Crankshaft bearings 75 

(Crankshaft and bearing troubles 

and remedies 76 

Crankshaft and connecting-rcd 

bearing shims 75 

Crankshaft lapping 83 

Crankshafts 72 

Curing excessive lubrication.. 60 

Curing noisy tappet 252 

(^ut-outs 286 

Cutting valve-key slots 258 

Cycles of engine operation 11 

Cylinder and crankshaft sub- 
group 22 

Cylinder forms and construc- 
tion 22 

Cylinder heads 39 

Cylinder multiplication 12 

Cylinder repairs 31 

. cylinder heads 39 

grinding out cylinder bore.. 41 
locating noises by means of 

stethoscope 37 

making gaskets 38 

methods of cylinder lapping. 41 

removal of carbon 31 

repairing cracked water jack- 
ets 43 

replacing pistons in cylinders 46 

simple dead center indicator 42 

welding breaks In cylinders. 43 

working in valve cages 46 


Demountable rims 660 

Deposits of carbon in cydinder 15 

Deppfi gas generator 192 

Disc clutch 356 

Double brake drum 610 

Double carburetors for multi- 
cylinder motors Ill 

Double-nozzle type 109 

Dragging brakes 617 

Driving reaction 579 

Dummy brake drum 618 


Edwards .carburetor 137 

Electric brakes 613 

Electric drive 404, 489 

Electric transmissions 405 

Electrically operated gears 393 

Eliminating noises in gasoline- 
car brakes 620 

Elliott type of front axle 492 

Engine group 3 

carburetion sub-group 3 

cooling system 5 

cylinder and crankshaft sub- 
group 3 

exliauBt system 5 

flj-whpcl 7 

ignlilou syBiem 

iulcl nuct elhausi valKs... 

llgbttng system 

lubrlcailoD sjatem 

siarilDg system 

Engine Iroubies and re^Mlrs. . 

Exhaust systeoi XT!I 

ExbBUSl-Tslve setliiie .- . . U9 
Expanding-baDd, or rilis ilUrh SE& 
External lubricetion IIS 

Failure of clutch lo lokp bold. 3 
Failure or tuel lo flaw fii^m full 

grSTlTy lank ... I 

Failure lo slarl ensine. ., . 

Fans . . 3 

FpIIowk gear aha(iiT 4 

Fiprce dutch 3 


daesca of trainee B1 

afflirart mi iiprlii«» 

(ntnut imuhloA and ixnnlrS' 

sentml clunclitisiLcB 

prv«M>d-«Ji-«l rraiova 

rigid (raaieB , . (I 


twudvBL-y In dexicn 

(jpHK of fraiiw* tl 

FrirUotialpIiiiesbockabMrtiQr.. fii 

FtMR drirw « 

Ftvtmg irrlcl plus and biuh- 

ttigs j 

Krletton | 

FroBt axles || 

axle bnarlBpi B 

luaiMiatB , (j 

iTtiahlc* niMl rxpoirs 6 

iyp»» t 

Kront-nkeel drlte...... ^I 

tmnnH .,,-...., 4J 

dlHoulllcs of tnttianilsaloii.. 41 

rrti-llnn.dllai> tnnamtHbm M 



"H & N" duplex carburetor 189 

Handling clutch springs 373 

Handling shaft in machines... 81 

Handy spring tool 417 

Heating 410 

Heating charge 209 

Helical and herringbone gears. 429 

Hoists and cranes 18 

Holding crankshaft 81 

Holding valve springs com- 
pressed * . . . 25G 

Holley carburetors 125, 180 

Hydraulic brakes 614 

Hydraulic gear 403 


Individual clutch 395 

Individual pump pressure feed- 
ing 317 

Inlet manifold design and con- 
struction 205 

Inner tube repairs 689 

inserting new sections 691 

large patches 689 

simple patches 689 

Inside' casing forms 683 

Interchangeable Continental 

tires 652 

Interchangeable Michelin tires 651 

interlocking devices 391 

Internal cooling and scaveng- 
ing 301 

Internal-expanding brakes 606 

Internal-gear drive for trucks. 585 


Jacking-up troubles 594 

Johnson carburetor 1 67 


Kingston carburetors 127 

Knight sleeve valves 272 

Knocking in engine 15 


T^rge patches in inner tube re- 
pairs 689 

I^rge patches in inner tube re- 
pairs (continued) 

cleaning hole 681» 

preparing patch 690 

vulcanizing patch 690 

layouts of equipment for tire 

repairs 685 

Leaks in gasoline line 205 

Lemoine type of front axle 494 

Ix)cating rear-axle trouble 602 

Lock on fuel line 219 

I^nguemare carburetor 139 

I^st motion and backlash 469 

Lost motion in wheel 469 

Lubricating multiple-disc 

clutches 379 

Lubricating transmission gears 420 

Lubrication of other parts 321 

Lubrication troubles and reme- 
dies 325 

bending oil pipes 329 

care of lubricant in cold 

weather 325 

mammoth grease gun 325 

oil filtering outfit 328 

oil settling tanks 328 

oil tank and outfit for testing 
bearings * 326 


Machining crankcases 89 

Magnetic clutch 364 

Making gaskets 38 

Mammoth grease gun 325 

Mandrel for turning pins 57 

Marvel carburetor 157 

Master carburetor 134 

Material for crankshafts 72 

.Mending breaks 8$ 

Misfiring, causes of 203 

Missing of explosions 15 

Mixing gas-engine cylinder oil 

with fuel 330 

Modem selective types of slid- 
ing gear 382 

Modern tendencies in design.. 85 

splHsIi lubrii.-ariun 

MouDiliif! iiiaron on jarh^- 


Muffler [ruNblvs . . , 

Miiltiiili^disc oluKh-s failing ■, 


.MiiItiiiIt^no2;!l>- ii.t|>iir>-'(.r^ 

Nolfiy I 

"il nilciiiiK oiirn' 

OtiK HIJll KVttHI-H. 

Ciit MciiliiiK riink^. 


Radiators and piping 289 

Railway car Deeds 39.", 

Rayfleld carburetor 147 

Rear-axle boualngs uS9 

Rear-axle lubrication 594 

Rear asles ">6!l. "iST 

assembling 599 

dlaasaembllng rear consinic- 

- tlon 698 

transQilssioo 5G9 

irrmlilfi! iind repairs 594 

truss rods 597 

tyijea of rear axlea 581 

Rear-end changes In framea... 523 

rtear-wheel bearings 593 

Renioval o[ carbon 31 

Removal and replacement of 

pistons 53 

Removing valve 252 

Removing valve spring '. . 253 

Repairing cracked waier Jackets 43 
Repairing poppet valves and 

valve parts 2ri2 

Repairs, engine IG 

Replacements 302 

Replacing clinch leathera 371 

Replacing pistons In cylinders 46 

K^-iTv-. i;iiil(s 217 

Retreading In tire repair 696 

Retreading vnlcanizers 684 

Reversed Elliott type of (ronl 

axle. 492 

Rigid frame 513 

RInia 654 

clincher 654 

demountable (160 

kinds 654 

other removable forms (171 

Perlman rim patents 668 

plain 654 

quick-detachable Gu4 

standard sizes of 669 

Riveting frames 527 

Roller bearings 332,602 

Sagging of frames >• 

Sand blisters in tire repairs... 6 

Saving balls 4 

Scbebler carburetors I 

Selective type of sliding gear. 3 

Senil-elipiic sjirings 5 

Semi-reversible gfar 4 

Senrab tarbiirctor 1 

Shackles and spring boms tor 

springs 1 

Sheet-steel wheels 6 

Shock absorbers 5 

coll springs 5 

friction a 1-plate type 5 

fund Ion 5 

general classes of absorbers a 

hydraulic suspensions 5 

overload springs b 

Side-wall vnlcanlzer 6 

Simple (Ire patches 6 

Single-punip pressure feeding. 3 

Sliding gears 3 

Slip Joints 6 

Slipping clutch 3 

Spindle troubles and repairs. , 5 

Spiral bevels t 

Spiral gears 4 

Splash lubrication 3 

Spring construction and ma- 
terials 6 

Spring lubrication 5 

Spring troubles and remedies. 5 

Springs r. 

Spur and bevel type of steerlnfc 

gear 4 

Spur gears 4 

Siiiiidard filzps ofilresandrlms 6 
Steering-gear assembly (roubles 

and repairs 4 

Steering gears 330, 4 

Steering group 

Steering rod, or drag link i 

Steering levers In front of axle 4 

Steering wheels 4 

Stewart carburetor 1 

Bunaerman ufpiy rarburetor. . 

Tables of valve settlnsa 23) 

Taking out a valve 261 

Tank placing 211 

Testing oils for acid, etc 323 

Testing alze at new piston 59 

Tbree-quarter elliptic springs. 332 

Three-quarter floating axle 5SS 

Throttle loose on shaFt IH 

Throttle and spark levers 471 

Throttle valves 103 

Throwing in clutch 379 

Timing Knight motor 276 

Tire repairs 677 

inner tube repairs 68S 

Inside casing forms 6S3 

layotits ot equipment 6Sn 

materials GS9 

outer shoe, or casing repairs 6A2 

retreading vulcanizers 6R4 

side-wall vulcanlier 6S3 

small tool equipment GST 

types or vulcanizing oiilflts.. 679 

Tire valves 675 

Tires 645 

Torque bar and lis function... 577 

Tracing a ring knock 76 


Water cooling 

anti-freezing solullons 


radiators and piping 

Water-Jackel Jng 106 

built-on jackets 

Integra.! Jackets 

welded applied jackets 

Webber aulomatlc carburetor. . 
Welding breaks In cylinders. . . 

Welding shafla and cases 

Wheel pullers 

Wheel sizes 

Wheel troubles and repairs,.. 


Whiton gear-rutUng machlnp,. 
Wire wheels 

Wobbling wheels 507 

Wood frames 515 

Wood wheels 624,637 

Working In bearings 416 

Working In valve cages 46 

Workstand equipment 595 

Worm-gear types 455 

Worm gears .' 432 


Zenith carburetors 117 

adiustmenta 117 

changing the compenHalor. . . 118 

changing the main Jet IIS 

duplex model adjustments,. 120 
horizontal type of adjust- 
ments and changes 119 

slow-speed adjustmeni 11!) 

lo replace main Jet IIR 

NOV 1 1918 

3 9016 02111 1862