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Geo. B. Selden in his "Benzine Buggy.' 

The present day motor car. 













TOTAL ISSUE, 18,000 



6 & 8 BOUVERIE ST., B. C. 




The purpose of this book is admirably expressed in the following 
quotation taken from the Buick instruction book: "To derive the 
greatest amount of satisfaction and pleasure from the use of his car the 
driver should have a complete understanding of the mechanical principles 
underlying its operation. Merely knowing which pedal to press or which 
lever to pull is not enough. The really competent driver should under- 
stand what happens in the various parts of the car's mechanism when he 
presses the pedal or pulls the lever. He should know the cause as well 
as the result." 

When we consider the complexity of modern automobiles from a 
mechanical standpoint, with the duties that are required of them, 
together with the fact that the great majority of them are operated by 
men with little or no experience in the handling of machinery, the 
automobile stands as one of the most remarkable machines that the 
ingenuity of man has ever produced. The operating expense of the 
automobile has already assumed a large place in the budget of the 
American people. Although it is so built that the owner may secure good 
service from his automobile with very little knowledge of its construction, 
still it is evident that an intimate acquaintance with its details should 
enable him to secure better service at less expense and at the same time 
to prolong the useful life of the car. 

It is with the hope of increasing the pleasure of automobile ownership 
and reducing the trouble and expense of operation that this book is 
offered. It is planned primarily for use in the University Extension work 
in Wisconsin, for the instruction of those who drive, repair, sell, or other- 
wise have to do with motor cars. It is largely the outgrowth of a series 
of lectures on the subject which were given in twenty-three cities of 
Wisconsin during the past winter. 

The thanks of the authors are especially due to Mr. M. E. Faber of 
the C. A. Shaler Co. for assistance in preparing the section dealing with 
tire troubles, to Prof. Earle B. Norris for much of the chapter on Engines 
and for editing the manuscript and reading the proof, and to the many 
manufacturers who have liberally assisted in the preparation of the work 
by supplying their cuts and other material. 

G. W. H. 
Sept. 15, 1915. 





1. The steam propelled car 1 

2. The electric car 1 

3. The gasoline car 2 

4. Types of cars 2 

5. The chassis 2 

6. The frame . 6 

7. The springs 6 

8. The front axle : 8 

9. The steering gear 10 

10. The rear axle 12 

11. The differential 13 

12. The power plant and transmission 14 

13. The torque arm 15 

14. Strut rods 16 

15. Brakes 16 

16. Wheels 18 

17. Tires 19 

18. Rims 20 

19. The speedometer drive 21 

20. Control systemr 23 



21. What is an explosion? 25 

22. Cycles 25 

23. The four-stroke cycle 26 

24. The order of events in four-stroke engines 27 

25. The mechanism of four-stroke engines 28 

26. Valve timing and setting 29 

27. Valves 30 

28. Valve arrangements 33 

29. The Knight engine 34 

30. The rotary valve 34 

31. Two-stroke engines 35 

32. The flywheel 38 

33. Ignition .39 

34. Clearance and compression ' 39 

35. Piston displacement 39 

36. Cylinder cooling 40 

37. The muffler 40 

38. Horse power of engines 41 




39. Single- and multi-cylinder engines 43 

40. Power plant and transmission arrangements ". . . . 44 

41. Modern automobile power plants 50 

42. Constructional features of four- and six-cylinder engines 56 

43. Eight- and twelve-cylinder power plants 60 

44. Clutches 64 

45. Change gear sets 66 

46. Planetary gearing 67 

47. Universal joints and drive shaft 69 

48. Final drive 70 

49. Types of live rear axles 71 


50. Hydrocarbon oils 75 

51. Fractional distillation of petroleum 75 

52. Principles of vaporization 76 

53. Heating value of fuels 79 

54. Gasoline gas and air mixtures 79 

55. Principles of carburetor construction 79 

56. Schebler, model L carburetor 82 

57. Schebler, model R 84 

58. The Holley model H carburetor 86 

59. Holley model G 87 

60. Stewart model 25 89 

61. Kingston model L 90 

62. Marvel carburetor 91 

63. Stromberg, model H 94 

64. Zenith model L 94 

65. Rayfield model G 95 

66. Carter model C 97 

67. General rules for carburetor adjustment 98 

68. Carburetor control methods 99 

69. The gravity feed system 99 

70. The pressure feed system 100 

71. The vacuum feed system 100 

72. Intake manifolds 102 

73. Care of gasoline 102 


74. Friction and lubricants 103 

75. Cylinder oils 104 

76. Viscosity 104 



77. Flash point 104 

78. Fire test and cold test 104 

79. General notes on lubrication 104 

80. Splash system of engine lubrication 106 

81. Splash system with circulating pump 106 

82. Full forced feed system Ill 

83. Mixing the oil with the gasoline 113 

84. Selection of a lubricant 113 

85. Directions for lubrication 114 

86. Cylinder cooling 117 

87. Water cooling systems 117 

88. Air cooling 122 

89. Cooling solutions for winter use 123 



90. Fundamental electrical definitions 127 

91. Direct and alternating current 127 

92. Dry batteries 128 

93. Storage batteries 128 

94. Series and parallel connections 129 

95. Battery connections for ignition purposes 130 

96. Simple battery ignition system 130 

97. The three terminal coil 132 

98. Timers 135 

99. Spark plugs 135 

100. Master vibrators 136 

101. The high tension distributor system 137 

102. The Connecticut automatic ignition system 139 

103. The Atwater Kent system 141 

104. The Westinghouse ignition system 144 

105. The Delco system of ignition 147 

106. The Remy-Studebaker ignition system 149 

107. Spark advance and retard 151 

108. Automatic spark advance 151 



109. Principles of magnetism : 153 

110. Mechanical generation of current 155 

111. Low and high tension magnetos 156 

112. Armature and inductor types 156 

113. Remy model P magneto 157 

114. The Connecticut magneto 160 

115. Dual ignition systems 160 

116. Eisemann high tension dual ignition 161 

117. Eisemann automatic spark control 163 

118. The K-W high tension magneto 163 



119. The Dixie magneto 16f > 

120. The Bosch high tension magneto 167 

121. The Bosch dual system 170 

122. Bosch two-independent system 173 

123. The Ford magneto and ignition system 174 

124. Magneto speeds 175 

125. Timing the magneto 176 

126. Battery vs. magneto ignition 177 

127. General suggestions on magnetos 177 

128. Common magneto ignition definitions 177 


129. Starting on the spark 179 

130. Mechanical starters 180 

131. Air starters 180 

132. Acetylene starters 180 

133. Electric starters 181 

134. Storage batteries 181 

135. Battery charging 185 

136. Wiring systems 187 

137. The Ward-Leonard system 187 

138. The Delco system 190 

139. Gray and Davis starting and lighting systems 193 

140. Wagner starting and lighting system 197 

141. The Westinghouse single-unit system 199 

142. two-unit system 200 

143. The U. S. L. electric starting and lighting system 204 

144. Jesco single-unit electric starter and lighter 205 

145. Care of starting and lighting apparatus. 207 

146. Starting motor troubles 208 

147. Generator troubles 209 

148. Battery troubles 209 

149. Winter care of batteries 209 

150. "Don'ta" on starting equipment 210 



151. Classification of troubles 213 

152. Power plant troubles 214 

153. Mechanical troubles in engine 216 

154. Carburetion troubles 221 

155. Ignition troubles 223 

156. Lubricating and cooling troubles 226 

157. Starting and lighting troubles 228 

158. Transmission troubles 228 

159. Chassis troubles . . 229 




160. Preparations for starting 231 

161. Cranking 231 

162. How to drive 232 

163. Use of the brakes 233 

164. Speeding 234 

165. Care in driving 234 

166. Driving in city traffic 235 

167. Skidding 236 

168. Knowing the car 237 

169. The spring overhauling 238 

170. Washing the car 240 

171. Care of tires 240 

172. Tire troubles 243 

173. Figuring speeds 247 

174. Interstate regulations 248 

175. Canadian regulations 249 

176. Touring helps-route books 250 

177. Cost records 250 

INDEX . . 255 



Automobiles may be classified according to the type of power plant 
used, as steam, electric, and gasoline; or they may be divided into two 
classes according to use, as pleasure cars and commercial cars. 

1. The Steam Propelled Car. The steam engine has the advantage of 
-flexibility. All operations such as starting, stopping, reversing, and 

acquiring changes of speed can be done directly by throttle control. 
By opening or closing the throttle, more or less steam is supplied to the 
engine, and the power is increased or decreased in proportion. When 
climbing a hill, all that is necessary to do is to give the engine more steam 
and consequently more power. The advantage of the steam engine in 
being able to start under load eliminates the clutch and also the trans- 
mission or change speed gears, the engine being connected directly to 
the rear axle. 

The disadvantage of the steam engine is that it is necessary to fire up 
before starting, in order to generate enough steam to run the engine and 
propel the car. The steam machine requires large quantities of water 
to form the steam and that means frequent refilling of the water tank. 
They also require constant attention to the water and fuel pumps. The 
burning of the fuel under a boiler to generate the steam introduces an 
element of danger from fire and also makes the steam plant less efficient 
than the internal combustion engine. 

2. The Electric Car. The advantages of the electric car are similar to 
those of the steam car inasmuch as it is very flexible and can be controlled 
entirely by the controlling levers. By cutting out or in resistance, more 
or less current is supplied to the motor and the power of the motor is 
proportional to the flow of the current. The electric car is especially 
adapted to the use of women and children in cities. It is easy riding, 
clean, and very quiet. 

The disadvantages are that it is not suitable for long drives, heavy 
roads, or hilly country. On one charge of the battery the average car 
will run from 50 to 100 miles^ ^depending on the speed and condition 
of the roads. If the car is run at high speed, the battery will not 



drive the car as far as it will when running at moderate rate. This 
car is also limited to localities where there are ample facilities for charging 
the storage batteries. 

3. The Gasoline Car. The gasoline engine is much more economical 
than either the steam or electric, and after being once started has great 
flexibility. It is also better adapted for touring purposes than either 
of the others and does not require any more attention from the operator. 
The average car carries enough fuel to run it 200 to 400 miles 
without a stop and then it is necessary to fill the gasoline tank only, 
with an occasional quart or two of water for the radiator. With proper 
care, the engine will run as long as the gasoline supply and electrical 
system will hold out. 

The disadvantages of the gasoline engine as compared with the steam 
engine or electric motor are, first, the gasoline engine is not self-starting; 
and, second, it lacks overload capacity. This means that some method of 
changing the speed ratio of the engine to the rear wheels is necessary in 
order to acquire extra power for climbing hills, for heavy roads, and also 
for reversing the car, as it is not possible to reverse the ordinary four- 
stroke automobile engine. The gasoline engine will not start under load, 
which necessitates the use of a clutch, so that the engine can be started 
and speeded up before any load is thrown on. Apparently there are a 
great many disadvantages to the gasoline engine but in reality they are 
very few, for with the proper handling of the spark and throttle control- 
ling levers it is not necessary to keep continually changing gears. The 
speed change lever need not be used except for starting, stopping, hill* 
climbing, and on bad roads. 

4. Types of Cars. In general, the parts of the pleasure and commercial 
cars are the same except that the pleasure cars are built much lighter than 
the commercial cars. In the pleasure car everything is planned for 
comfort and speed, while the commercial car is built for heavy loads and 
is generally intended to be driven at low speed. 

The principal body types of pleasure cars are, the limousine, the 
touring car, the coupe, and the roadster, as shown in Fig. 1. 

The commercial cars are built for light, medium, and heavy duty. A 
few of the commercial types are shown in Fig. 2. 

The cycle car is a name commonly given to small cars which have less 
than 70 cu. in. piston displacement or a tread of less than 56 in. 

5. The Chassis. The principal parts of the gasoline automobile are 
the frame, springs, axles, wheels, power plant and auxiliaries, clutch, 
transmission system, controlling apparatus and body. The chassis, as 
shown in Fig. 3, includes all parts with the exception of the body and its 
accessories. The functions and types of these parts will be taken up 







2. Types of commercial canp, 



Power plant 
Universal joint 

-Control levers 
-Drive shaft 

Torque crrm- 

Torque rod 


Brake equalizers 
3 rake 

-Storage baffery 

Universal joint 

Change aears 

FIG. 3. Chassis of the Studebaker "Six. 


6. The Frame. The automobile frame is a very important part of 
the car, due to the fact that it supports the power plant, transmission 
mechanism, body, etc. The frame is attached to the springs, which in 
turn are fastened to the axles. Frames are made either of wood or metal 
.or a combination of the two. The metal frames are usually of channel- 
section steel. The wooden frames may be either of the solid timber type 
or of laminated strips glued together and sometimes reinforced by steel 
strips. This type is very strong and light and does not transmit so much 

FIG. 4. Channel steel frame. 

of the vibration as the steel frame. Figure 4 shows a pressed steel channel- 
section frame. Figure 5 shows a frame made from second-growth ash and 
used on the Franklin car. 

7. The Springs. The frame of the automobile is supported by 
laimated leaf springs. Coil springs are used only in places where a great 
deal of strength is needed in a small space and where quick action is 
required. The springs under the frame of an automobile must be gradual 

FIG. 5. Franklin wood frame construction. 

and easy in their action, and this is why the laminated leaf spring is used. 
The strength and resilience of the leaf spring can be varied by changing 
the number of leaves or by varying the width or length of the leaf. It 
also has an advantage over the coil spring in that if one leaf breaks the 
spring is still serviceable, while in a coil spring if a coil breaks the spring 
is no longer of any use. 

The laminated spring is built up of a number of leaves varying in 
length, the longest leaf being on the concave side of the spring and the 



other leaves built on this one in the order of their length. The ends of 
the long leaf are bent around to form eyes so that they can be fastened to 
the frame by a clevis or other means. 

The laminated leaf springs, as shown in Fig. 6, are built in the follow- 
ing forms: cantilever, semi-elliptic, three-quarter elliptic, full-elliptic, 
and platform springs. 

The Cantilever spring is fastened flexibly to the frame at one end and 
the center and carries the axle at the other end. There is another 
type of (jantilever spring which has a single rigid fastening to the frame. 
This is also called a quarter-elliptic spring. 

The (semi-elliptic spring usually has its center fastened to the axle 
while thl two ends support the frame. This type of spring is generally 
used to ^upport the front end of the car, because this type has the least 
amount of side-sway. Since the front axle is used for steering purposes, a 
great amount of flexibility is not desired. 

The three-quarter elliptic spring consists of a semi-elliptic member, 
to one end of which is attached a quarter-elliptic member. This type 
is supported in the middle of the semi-elliptic spring and is connected 
to the frime at one end of the semi-elliptic and the free end of the quarter- 
elliptic sbrings. 

The ifull-elliptic spring consists of two semi-elliptic springs con- 
nected together at the end, supported at the middle of one semi-elliptic 
and carrying the load at the middle of the other. Either the three- 
quarter or the full-elliptic types have greater flexibility than the semi- 
elliptic tiype. 

The platform spring consists of three semi-elliptic springs fastened 
together. Two of the members are parallel to the sides of the car arid 
the third is inverted and is parallel to the cross members. The car frame 
is attached to the front end of the side members and to the middle of the 
cross member. The middle of the side members rests on the spring 

8. The Front Axle. The front axle consists of the center, the knuckles, 
a steering arm, a third arm, a plain arm, and the tie rod. The centers 
are either I-beam, as shown in Fig. 7 or tubular as in Fig. 8, and they 
may be either straight or dropped center types. Square centers are 
sometimes used on heavy trucks. 

The }-beam centers are made either of drop forgings or of cast steel 
and are heat-treated to do away with brittleness and give strength and 
toughness. The tubular centers and tie rods are made from the best 
high-grade seamless steel tubing and the yokes are either pinned or 
brazed on the ends of the tubes. In the I-beam centers the yokes form 
a part of the forging or casting. The I-beam construction is the strong- 
est but is not quite so flexible as the tubular center. 


The front wheels are fastened on the spindle of the knuckle and run 
on cup-and-cone ball bearings or on roller bearings as shown in Fig. 7. 
The spindle is set so that the front wheels have a camber of about 2 in., 
that is, the tops of the wheels are about 2 in. farther apart than the 

FIG. 7. I-beam front axle construction. 

bottoms of the wheels. This is to conform to the crown of the road and 
to bring the point of contact between the tire and the road in line with 
the king-bolt. 

In order to make the car steer easier and have a tendency to run 
straight ahead, the front wheels should toe in from % to ^ in. This is 
done by adjusting the length of the tie rod. 

FIG. 8. Tubular front axle. 

The knuckles are fastened in the axle yokes by king-bolts and are 
free to swing about 35 either way from the center line of the axle. 
This is necessary in order to allow the wheels to follow a curve when turn- 
ing. Between the top of the axle yoke and the knuckle there should 



be a ball or roller bearing or a renewable bronze washer to carry the 
load and yet allow the knuckle to turn easily. 

The king-bolt should fit in a bronze bearing in order to insure easy 
movement and a small amount of wear. The steering and third arms, 
which are generally combined in a single forging, are keyed to one 
knuckle. The third arm is connected by the tie rod to the plain arm, 
which is keyed to the other knuckle. The general layout of the steering 
apparatus is shown in Fig. 9. The steering arm is connected by the drag 
link to the pitman arm or steering lever on the base of the steering 


Steerinq wheel 

Sfeer/na column -: 

Pitman arm 
-Drag link 

Fig. 9. Arrangement of steering apparatus. 

9. The Steering Gear. The steering gear is the part of the mechan- 
ism that operates on the knuckles to turn the front wheels in response 
to movements of the hand wheel. 

Figure 10 shows the essential parts of a double worm steering gear. 
Inside the steering column is the steering tube, the upper end of which 
is connected to the hand wheel while the lower end carries a double- 
threaded worm. The worm meshes with two half-nuts, one with a right- 
hand and the other a left-hand thread. Two rollers, which are attached 
to the yoke that operates the pitman arm or steering lever, bear against 
the lower ends of the half-nuts. The operation is as follows: Turning 
the hand wheel turns the tube and worm in the same direction, which 
causes one half-nut to rise and the other to descend. This pushes one 
roller down and lets the other rise. The yoke is given the same motion 



and transmits it to the pitman arm, which pushes or pulls on the drag 
link and thus turns the knuckle and wheels. 


Spark lever 
/ Throttle, lew 

X js' 


Stationary tube 

Throft/e fube 

"Adjusting nut 
Grease plug 

, Throttle gear 

- -fy&r/c a ear 

FIG. 10. Double worm steering mechanism. 

Figure 11 shows the worm-and-gear type. The worm is fastened to the 
steering tube and is turned with the hand wheel. The gear shaft carries 
the pitman arm, which connects to the knuckle steering arm by the 
drag link. 


These steering gears are non-reversible, because while the action 
of the hand wheel is readily transmitted to the front wheels the jarring 
of the front wheels on rough roads can not be transmitted back to turn 
the hand wheel. 

Grease Cup 


FIG. 11. Worm-and-gear steering mechanism. 

10. The Rear Axle. The rear axle must carry this end of car and 
also provide means of giving power to the rear wheels to propel the car. 
This is done in two general ways, and the corresponding types of axles 
are called "dead" and "live" axles. 

Figure 12 shows a truck chassis with a dead rear axle. It is somewhat 
similar in construction to the ordinary wagon axle, as it is made up of a 

FIG. 12. Heavy truck, chassis with dead rear axle. 

solid bar with spindles machined on the ends for the wheel bearings. 
The wheels have large sprockets on the inside which are driven by chains 
from other sprockets on the ends of a "jackshaft" near the middle of the 
car. This type of axle is used principally on heavy trucks where it is 


necessary to have a solid construction and provide for a large reduction 
in speed. 

For pleasure cars, the live axle is generally used. The general 
arrangement of a car with a live axle was shown in Fig. 3. In Fig. 13 is 
shown in detail the construction of a typical live axle. In this type the 
axle turns and drives the rear wheels with it. The axle is surrounded 
by a stationary housing which supplies the bearings for the wheels and 
the axle and which also supports the car through the springs. The 
live axle receives its power near the center, usually through a set of 
bevel gears which give the desired speed reduction and also make the 
necessary right angle change in the power transmission. 



FIG. 13. Live rear axle. 

11. The Differential. Some provision has to be made to drive the 
rear wheels positively in either direction and yet allow one wheel to run 
ahead of the other when turning a corner. This is done by dividing the 
live rear axle at the center and connecting the two halves by a differential 
gear, the details of which are shown in Fig. 14. Each half of the live 
axle (called the main shaft in Fig. 14) has a bevel gear on its inner end. 
These bevel gears face each other and are called the differential gears. 
They are connected by from two to four differential pinions spaced at 
equal distances around the circle. The power is applied at the centers 
of these differential pinions so that they act like the doubletrees or 
eveners on a team of horses, allowing one wheel to run ahead of another 
or to lag behind but still maintaining an even pull on the two differential 
gears. Referring to Fig. 14, the power from the engine is brought back 
to the driving, pinion and this delivers it to the large gear called the bevel 
ring. This bevel ring is fastened to the differential case, which, therefore, 
receives the power from the bevel ring. The differential case turns the 
spider with it and, as this spider carries the differential pinions, these 
pinions are carried around with a force applied at their centers. On a 



straight road the differential case, the spider, the differential pinions 
and the differential gear all revolve as one mass and there is no internal 
action in the differential. The differential pinions pull equally on the two 
differential gears on each side of them and they all revolve together. In 

FIG. 14. Differential gear. 

turning a corner the outer wheel has farther to go and hence must run 
faster. This makes the one differential gear turn faster than the other. 
This causes the differential pinions to revolve on their axes, but they 
still continue to deliver power equally to the two wheels. 

FIG. 15. Arrangement of power plant and transmission system. 

12. The Power Plant and Transmission'. Figure 15 shows a typical 
arrangement of the power plant and the power transmission system. 
The engine is generally placed in the front end of the car, both for ac- 
cessibility and to balance the weight of the passengers in the rear part 


of the car. The engine is the most important part of the car. Its 
purpose is to transform the heat energy of gasoline into mechanical 
energy at the crank shaft for the purpose of driving the car. The power 
is delivered to the flywheel, from which the clutch takes it and passes it 
back to the transmission. In the transmission case is a system of gears 
for reducing the speed from the engine and increasing the turning force 
for starting purposes or for heavy driving, as in sand or on hills. 

The power plant is mounted on the frame of the car, while the rear 
wheels which are to finally receive and use the power are flexibly con- 
nected to the frame by springs. We must, therefore, have a flexible 
arrangement for taking the power from the power plant to the rear 
axle. This is usually accomplished by means of a propeller shaft and 
one or two universal joints (see Fig. 15). A universal joint is merely a 
double-hinged shaft connection (see Fig. 16) permitting the lower end of 
the propeller shaft to swing at will with the 
rear axle and yet receive power from the 

In the t ,car of Fig. 15 the engine and 
transmission are carried in the frame of the 
car and the first universal lies just back of the 
transmission. In the car of Fig. 3 the trans- 
mission with its change gears is placed just in 

Tii FlG - I 6 - Universal joint, 
front of the rear axle and is fastened solidly 

to the rear axle housing. This places both universal joints and the 
propeller shaft between the engine and the transmission. 

In addition to the engine proper, the power plant contains a number 
of accessories necessary for the operation of the engine, such as the 
lubricating system, the ignition system, the carburetor, the cooling system, 
and the starting system. In the so-called unit power plant the clutch 
and change gears are contained in a single unit with the engine. All 
these accessories will be taken up in the later chapters. 

In heavy trucks the system of power transmission is somewhat 
different from the pleasure car system just described. The power from 
the engine is carried through the clutch and back to the transmission 
located in the center of the chassis, as shown in Fig. 12. Here the power 
is turned at right angles in the rear part of the transmission and is given 
to a jackshaft lying across the car. The sprockets on the outer ends of 
this jackshaft drive the rear wheels through two chains. No universal 
joints are needed in the final drive, as the chains allow for the free motion 
of the rear axle. 

13. The Torque Arm. When the brakes are used in stopping a 
car, the brakes, being carried by the rear axle housing, tend to carry this 
Jiousing around with the wheels, likewise, the action of *he propeller 


shaft and the bevel pinion in driving the rear axle (see Fig. 14) tend to 
turn the axle housing over backward with the same force that is exerted 
on the bevel ring. This twisting action or "torque" must be taken 
care of in some way. This can be done by torsion rods as in Fig 15, 
or by a single bar called a torque arm or by a torsion tube around the 
propeller shaft, or it can be left entirely to the springs to take care of this 
action. If the torque is taken up by a housing around the propeller 
shaft as in Fig. 17, this tube is called the "third member" of the rear axle 
system and is securely bolted to the rear axle housing. This system does 
away with one universal joint, as only one at the front extremity of the 
propeller shaft is used. 

Strut roof- 

FIG. 17. Rear axle with torque tube and strut rods. 

14. Strut Rods. In order to preserve the alignment of the wheels or 
to keep one wheel from getting ahead of the other, strut rods are fastened 
to the brake flanges or spring seats, and extend to the front end of the 
third member as in Fig. 17 or to some part of the frame. 

15. Brakes. Brakes which act on the rear wheels are either of the 
contracting or expanding band type or the expanding shoe type. 

Figure 18 shows the general layout. This is known as a double 
internal type of brake. A steel brake drum is fastened securely to the 
wheel. Both bands expand and put pressure on the inside of the drum. 
The outside band, or the one next the wheel, is the emergency brake and 
is operated by a hand lever. The other, the service brake, is under the 
control of the driver through the medium of the foot pedal. The brake 
bands are carried by brake flanges near the ends of the rear axle housing. 
The two sets are entirely independent of each other. Another type of 



internal expanding band brake that uses two brake drums is shown in 
Fig. 19. The action is similar to the above. In this case the smaller 




FIG. 18. Double internal brake with single drum. 






FIG. 19. Double internal brake with two drums. 

band is used for the emergency. Figure 20 shows a type of brake known 
as the internal-external brake. There are two bands working on the 




same drum. One set contracts around the outside of the drum and the 
other set expands against the inner circumference. The outer band 

constitutes the service or foot brake and 
the inner band the emergency brake. 

All bands, either contracting or ex- 
panding, are faced on the rubbing side 
with an asbestos preparation that is 
capable of standing a great amount of 
wear and is not easily burned out. Some 
types that use the expanding shoe have 
a cast-iron shoe that is pressed against 
the inside of the steel drum on the wheel. 
A typical mechanism for operating 
the expanding shoes or drums is clearly 
shown in Fig. 18, where the emergency 
band is shown expanded while the ser- 
vice brake is in the running position. 

16. Wheels. Automobile wheels are 
classified as artillery wheels (with wooden 
spokes), wire wheels, and cast- or pressed- 
steel wheels, the latter being limited to 
heavy duty trucks. 

Artillery Wheels. The artillery wheel, shown in Fig. 21, is built 
of second-growth hickory. The spokes are fastened together at the 


"" band 

FIG. 20. Internal-external 

Felloe , 

C/arnp \ 

rim Fe//oe. bane/ 

Demountable rim Felloe band 

FIG. 21. Artillery wheel. 

FIG. 22. Wire wheel. 

hub of the wheel by a series of interlocking mortise-and-tenon joints and 
the outer ends are turned down to fit in holes in the wooden felloe band. 


The hub casting, which serves to hold the inner end of the spokes, also 
acts as the bearing housing for the hub bearings, on which the wheel 

Wire Wheels. The wire wheel is shown in Fig. 22. On account of 
the scarcity of second-growth hickory, which is the only acceptable 
material for artillery wheels, some companies are building wire wheels 
which are modifications of the bicycle wheel. Wire spokes are inter- 
laced between the hub and rim in such a manner that the wheel is held 
rigid and withstands both the direct loads and side strains. 

In the artillery wheel, the load is carried by the spokes on the under 
side. In the wire wheel, the load is carried by the spokes above the 

The advantages claimed by the wire wheel manufacturers are that the 
wheel is reduced in weight about 30 per cent. ; is more resilient, which 
makes an easier riding car; will stand greater radial strain; and is fully as 
strong as the artillery wheel. 

Wearing Surfa ^^^^ /Breaker Strips 

Inner Tube 

Piano W: 

FIG. 23. Section of pneumatic tire. 

17. Tires. The tires used on pleasure cars are usually of the pneu- 
matic rubber type. Some are being filled with a spongy substance that 
makes them more of a cushion form and some have bridges of para 
rubber instead of an air cushion. The lighter commercial cars use solid 
rubber tires, the heavier trucks use steel tires, while some are using 
wooden blocks. The wooden blocks and steel tires can be used only on 
the very low-speed trucks on account of there being no resilience in tires 
of these types. 

The pneumatic tire serves as a good shock absorber and eliminates 
a large portion of the road vibrations and jars before they reach the 
mechanism of the car. 

The general construction of the tire is shown in Fig. 23. Several 
layers of heavy canvas (friction fabric) are wound around two circular 
wire cables (beads) in the shape of a tire. This forms the foundation, 



which is filled with rubber gum to form the carcass of the tire. Around 
the carcass the cushion is built, which is an extra thickness of com- 
pounded rubber held in place by a double layer of canvas. This is called 
the breaker strip. Outside of this comes the tread. The tread is the 
part that comes into contact with the road and takes the wear. This 
whole structure is then vulcanized to make a solid unit. 

The inner tube, which is merely a rubber bag with a check valve 
to hold the air, is inserted in the casing and the casing is fitted on the 

FIG. 24. FIG. 25. 

FIGS. 24 AND 25. Types of detachable rims. 

rim in such a way that when the pressure is applied the bead grips the 
rim, and the flanges on the rim prevent the tire from sliding off sideways. 
18. Rims. Rims may be classified as clincher, detachable, and 
demountable, or a combination of two of these. The cuts shown in 
Figs. 24, 25, and 26 show sections of the Goodyear rims. Figure 24 
illustrates the detachable rim of two parts. The side ring can be easily 
removed from the groove by a screw-driver. The higher the inflation 
pressure in the tire the harder the side ring hugs the groove. This 
rim is used to a great extent on electric pleasure cars. 

FIG. 26. Demountable-detachable rim. 

Figure 25 shows a heavier type of detachable rim, quite general 
on gasoline pleasure cars. 

Figure 26 shows a rim which has both the demountable and detach- 
able features combined. With demountable rims, an extra rim with 
tire fully inflated may be carried. In case of a blow-out, the damaged 
tire and its rim may be quickly removed and the spare rim and tire put 
on. This saves considerable time in cases of tire trouble. 

Figures 27 and 28 show the rim made by the General Rim Co. This 



is a demountable rim and is locked on the rim at a single point. To 
remove the rim from the wheel the toggle nut is turned to its 
lowest position on the end of the clamping bolt, as shown in Fig. 28. 
This draws the clamping ring into the groove and the rim is re- 
leased and ready for removal. To replace the rim merely reverse this 

Felloe band 

Demountable rim 

Toggle nut 
FIG. 27. 

Felloe \ \ ^^^^ \ 
Felloe bane/ \ / UlP C/amp 
Demountable rim Clomping boft 
FIG. 28. 

FIGS. 27 AND 28. Demountable clincher rim. 

Figure 29 shows sections of the clincher rim as used on the Ford 
car, and also shows the method of removing the tire from the rim. 

19. The Speedometer Drive. Some device for indicating the speed 
should be installed on every car as the cost of one fine will purchase a 
reliable speedometer. 

Second Position 
of Tire Tool 

FIG. 29. Method of removing clincher tires. 

The drive may be taken from a gear attached to the transmission, 
as shown in Fig. 30, or from a similar attachment on one of the front 

Figure 31 shows a speedometer drive installed in the spindle of 
the steering knuckle and driven from a plate under the hub cap. This 
eliminates the use of an exposed gear and requires no attention except 
proper lubrication. Care should be used to see that the drive plate is 
properly replaced if the hub cap is removed for any reason. 



FIG. 30. Speedometer drive from transmission. 









FIG. 31. Speedometer drive through knuckle spindle. 



20. Control Systems. Figures 32 and 33 show the two prevailing 
control systems. Figure 32 shows the left-hand drive and center con- 
trol system generally used on cars with sliding gear transmissions. 









FIG. 32. Left-hand drive, center control. 

FIG. 33. The Ford control. 

The operation is as follows: The left-hand pedal operates the clutch 
and the other pedal the foot or service brake. The right-hand Jever 
operates the emergency brake. The left-hand lever operates the change 
gears as follows: To the left and ahead for reverse, to the left and back 


for low speed ahead, to the right and ahead for second speed ahead, and 
to the right and back for third or high speed ahead. This order of 
events is not standard for all cars. Every car has its own system of 
shifting gears. 

Figure 33 shows the Ford control system. This system consists of 
three foot pedals and one hand lever. The pedal on the left operates 
the clutch and controls the high and low speed. The hand lever also 
operates the clutch and when drawn all the way back sets the emergency 
brake. With the hand lever forward and left pedal up it is then in 
high gear. To get low speed ahead, the left pedal is pressed all the 
way forward; halfway in releases the clutch? The second or middle 
pedal marked "R" operates the reverse mechanism. To reverse the 
car the hand lever must be in a vertical position or the clutch pedal half- 
way in; then pressing on the reverse pedal drives the car backward. 
The right-hand pedal operates the foot or service brake, which is on 
the transmission. 

The chapters to follow will treat in detail of the various parts of 
the car, their construction, methods of operation, and maintenance. 


21. What is an Explosion? Practically all gasoline engines are 
driven by explosions which take place within the cylinder of the engine 
and drive the piston, thus causing rotation of the revolving parts of the 
engine. These explosions are in a way very similar to the explosions of 
gunpowder or dynamite. When a charge of gunpowder is fired in a 
cannon or gun, the gunpowder burns and produces gases which exert a 
tremendous pressure on the shell and force it from the gun. 

Practically any substance that will burn can be exploded if under the 
proper conditions. An explosion is merely a burning of some material 
taking place almost instantaneously, so that a great amount of heat is 
generated all at once. When any substance burns, it unites rapidly 
with oxygen from the air. If we want to get an explosion, it is necessary 
to have the fuel very finely divided and carefully mixed with air, so that 
the burning can be very rapid. Then, if we start the fuel burning, by an 
electric spark or any other means, the flame instantly spreads throughout 
the mixture and an explosion occurs. In a gasoline engine we take in 
gasoline vapor mixed carefully with air. This mixture is then exploded 
inside the cylinder of the engine. The force of this explosion drives the 
piston and the motion is transmitted through the connecting rod to the 
crank. To make the process continuous and keep the engine going, it is 
necessary to get rid automatically of the gases from the previous ex- 
plosion and to get a fresh charge into the cylinder ready for the next 
explosion. This process must be carried out regularly by the engine, in 
order to keep it running. 

22. Cycles. As we have just seen, an engine must supply itself with 
an explosive mixture so that the force of the explosion will cause the 
engine to move, and it must get rid of these dead gases and get in a fresh 
charge of gas and air and explode this so as to keep up the motion. 
There are in use at the present time two principal systems of performing 
this series of operations. These systems, or rather the series of opera- 
tions, are called cycles, and the engines are named according to the 
number of strokes it takes to complete a cycle. These two cycles, or 
systems of engines, are the four-stroke cycle and the two-stroke cycle. 

Remember that a cycle refers to the series of operations the engine 
goes through. In the four-stroke cycle there are four strokes or two 
revolutions. In the two-stroke cycle there are two strokes or one revolu- 
5 25 


tion. Many people leave out the word stroke and talk of "four-cycle 
engines" and "two-cycle engines." This causes the misunderstanding 
that many people have as to just what a cycle really is. A better way is 
to call them "four-stroke. engines" and "two-stroke engines." 

23. The Four-stroke Cycle. Figures 34, 35, 36 and 37 show an engine 
which operates according to the four-stroke cycle. The engine shown 
here is a vertical engine, that is, the cylinder is placed above the crank 
shaft (instead of being at one side) and the piston moves up and down 
in the cylinder. This is the prevailing form for automobile engines. 



FIG. 34. 


FIG. 35. 

Any engine consists of four principal parts: the cylinder, which is 
stationary and in which the explosion occurs; the piston, which slides 
within the cylinder and receives the force of the explosion; the connecting 
rod, which takes the force from the piston and transmits it to the crank; 
and lastly the crank, which revolves and receives the force of the explosion 
as the piston goes in one direction, and which then shoves the piston 
back to its starting point. A four-stroke engine has a number of other 
minor parts, whose uses will be brought out presently. This engine uses 
four strokes of the piston to complete the series of operations from one 
explosion to the next, and is therefore said to operate on the four-stroke 
cycle, or it is said to be a "four-stroke" engine. The first illustration, 
Fig. 34, shows the engine just drawing in a mixture of gas and air. This 
is continued until the piston gets clear down to the bottom of the stroke, 



and the cylinder is full of this explosive mixture. This operation is called 
the suction stroke. Then the valves are shut, as in Fig. 35, and the piston 
is forced back to its top position. This squeezes or compresses the gas 
into a space left in the top of the cylinder, and this process of compressing 
it is called the compression stroke. After the piston gets to the top, the 
gases are ignited or set fire to and burn so quickly that an explosion 
results and the piston is driven down again, as in Fig. 36. This is called 
the expansion or working stroke. When it reaches the bottom of the 
stroke, another valve is opened, and while the piston is returning to the 


FIG. 36. 


FIG. 37. 

top position it forces out through this valve the burned gases which occupy 
the cylinder space. This is the exhaust stroke. The engine is now ready 
to repeat this series of operations. These operations have taken two 
'revolutions or four strokes. A stroke means a motion of the piston 
from either end of the cylinder to the other end. Consequently, there 
are four strokes in the cycle of operations of this engine, and we therefore 
call it a four-stroke engine. 

24. The Order of Events in Four-stroke Engines. The various parts 
or events in the four-stroke cycle are shown on the diagram of Fig. 38. 
This shows the two revolutions of the four -stroke cycle divided up so as to 
show the crank positions when the different events occur. The diagram 
is drawn for a vertical engine with the crank revolving to the left, as 
shown on the engine of Figs. 34 to 37. This is the direction of rotation 


of an automobile engine to a person in the car looking forward toward the 

^Starting at the top of the diagram, we have just exploded the charge 
and as the crank swings over to the left the gases are expanded. Before 
the crank reaches the bottom, the exhaust valve is opened. This is 
kept open while the piston is returned to the top. The inlet valve is 
then opened and the suction stroke occurs as the crank and piston again 
descend. Just after the crank passes the bottom, the inlet valve closes. 
Both valves being now closed, the charge is compressed as the crank and 
piston rise again to the top. A short time before reaching the top, 
ignition occurs. This should be just far enough before the top so that 
the explosion or combustion is taking place as the crank passes the top 
and starts to descend on the expansion stroke. 

FIG. 38. Order of events in the four-stroke cycle. 

25. The Mechanism of Four-stroke Engines. In addition to the four 
principal parts previously mentioned, there are a number of other small 
parts which we will now discuss. First, we must have two valves located 
in the upper end of the cylinder, one for the purpose of letting in the 
fresh mixture of gas and air, and the other for the purpose of letting out 
the burned gases. Each of these valves opens once in a cycle, that is, 
once in two revolutions. In this engine (Figs. 34 to 37) the valves are 
shown in the T-head arrangement, the inlet valve being on the left and 
the exhaust valve on the right. These valves are of a form called poppet 
valves. They are mushroom shaped, with beveled edges which fit into a 
beveled seat. The valves are held shut by springs on the outside, which 
pull on the valve stems and hold them tightly against the seat, so that 


gases can not leak in or out, except when one of the valves is opened. 
To operate the valves, there are two push rods, one for each valve. 
These push rods receive their motion from the cams. On the lower ends 
of these rods are rollers, and these roll on cams on the cam shaft inside of 
the crank case. These cams have each a hump or projection on about 
one-fourth of their circumference. When one of these strikes the roller 
it raises it up, and this motion is transmitted through the push rod to the 
valve. After the projection of the cam has passed under the roller, the 
valve spring will close the valve and force the push rod back to the 
original position. 

Since the valves on an engine each work but once in two revolu- 
tions, the engine must be arranged so that the cams come around only 
once in two revolutions. To do this, the general arrangement is to 
put a small gear on the crank shaft and have this drive another gear, 
twice as large, on the cam shaft. In this way the cam shaft will run 
at just half the speed of the crank shaft. These gears are called half- 
time gears. 

26. Valve Timing and Setting. The exhaust valve of an engine opens 
on an average of about 45 before the end of the stroke, in order that the 
pressure may be reduced to atmospheric by the end of the stroke so there 
will be no back pressure during the exhaust stroke. At the end of the 
exhaust stroke, the exhaust valve should remain open while the crank is 
passing the center so that any pressure remaining in the cylinder may have 
time to be reduced to atmospheric. 

The inlet valve very seldom opens before the exhaust closes. Most 
manufacturers do not open the inlet until the exhaust closes, for fear 
of back-firing, although there is little danger of this except with slow- 
burning mixtures. The inlet valve opens, on an average, 10 late (after 
center). At the end of the suction stroke there is still a slight vacuum 
in the cylinder and the inlet is kept open for a few degrees past center to 
allow this to fill up and get the greatest possible quantity of gas into the 
cylinder. On an average, the inlet valve closes about 35 late, de- 
pending on the piston speed of the engine. 

In studying the valve setting of an engine, the first step, of course, is 
to observe the timing of the engine as it stands. To do this we must turn 
the engine by hand. By inserting a thin sheet of tissue paper between 
a valve stem and its push rod, we can tell when the valve opens and 
closes by noticing when the paper is gripped in opening the valve and 
when it is released in closing. The corresponding crank positions should 
be noted. We can then see whether it is possible to do anything to 
improve the valve setting. Valve cams are made for a certain valve 
setting and will give a certain angle of opening. This may become 
altered in several ways. Any excessive lost motion in the valve motion 


will result in a valve's opening too late and closing too early. Wear on 
the cam will have the same effect. If a cam shaft has been removed and 
replaced, the timing gears may be put together wrong. This would ad- 
vance or retard the whole series of events and can readily be found out 
when the timing is observed. 

The clearance or lost motion in the valve mechanism between the 
cam and the valve stem should be about 3^ 4 in. or less. In order to 
keep the valves quiet on their engines, some makers use a clearance of the 
thickness of ordinary writing paper, or about % oo in - If the clear- 
ance or lost motion is too great, it will cause the valve to open late and 
close early, and will also cause the cam to strike the roller a hard blow 
with the middle of its face, instead of catching it gradually at the beginning 
of the incline. It will also reduce the valve opening and possibly choke 
the engine. 

In a four-stroke engine the cam shaft revolves once for each two 
revolutions of the crank shaft. Consequently, a valve opening of 180 
will be represented by but 90 on the cam, and, for any given crank 
angle through which the valve is to be open, the corresponding cam angle 
will be but one-half the given crank angle. If an exhaust valve is to 
open 45 before the beginning of the exhaust stroke and close 10 after 
the end of the stroke, the total crank angle will be 

180 + 45 + 10 = 235 

The corresponding cam angle = ~ = 117^. By "cam angle" 

we mean the angle on the cam, from the point where it starts to open the 
valve to the point where the valve is seated again. An inlet valve that 
is to open 10 late and close 30 late, would have a total crank angle of 

180 - 10 + 30 = 200 

The corresponding cam angle = ^ = 100. 

27. Valves. The prevailing type of valve is what is called the poppet 
or mushroom type poppet, from its operation, and mushroom, from its 
shape. The exhaust valve must be opened by a cam because it must 
be opened against a pressure of 40 to 60 Ib. in the cylinder and held 
open while gases are forced out through it. The inlet valve may be 
opened by a cam or we may use a light spring and depend on the suction 
to open it. The suction type is, of course, cheaper to build, but it re- 
duces the capacity of the engine so that for the same power there is no 
saving. Consequently we find automatic inlets as a rule only on the 
small farm engines that are built to sell at a low price. To open an 
automatic valve, there must be a difference in 'pressure on the two sides 



of the valve equal to the tension of the valve spring. This tension may 
be reduced or increased by the weight of the valve, if vertical, and opening 
respectively downward or upward. For' high-speed engines an auto- 
matic valve is particularly unsuited, since a heavy spring must be used 
to insure quick closing at high speed. 

Poppet valves usually have 45 beveled seats as shown in Fig. 39, 
though occasionally flat valves are seen which rest on flat seats. The 
valves must be large enough to let the gases in and out of the cylinders 
freely. If they are too small they will cut down the power of the engine 
by not permitting it to get a full charge. The valves usually measure 
from one-third to one-half of the cylinder diameter. Valve diameters are 
usually measured by the opening in the valve seat (see dimension marked 
d in Fig. 39). The diameters of the inlet and exhaust pipes should at 
least equal this valve diameter and should be larger if possible. 

Fia. 39. 

FIG. 40. 

FIG. 41. 

The valve lift should, when possible, be sufficient to give the gases as 
large a passage between the valve and seat as they have through the 
opening d, Fig. 39. For a flat valve seat this would require a lift of one- 
fourth of the valve diameter. With a beveled seat, the gases pass 
through an opening in the shape of a conical ring having a width of 
passage equal to h f , Fig. 39. To have the necessary passage area, the 
lift h of the valve should be about three-tenths of the diameter. In 
most stationary engines this lift can be given the valve, but in high-speed 
engines it would be too noisy. This lift would then cause pounding and 
wear on the cams; it would require very stiff springs to make the valves 
follow the cams in closing and would be very hard on the valve seats and 
stems. For automobile engines the valves are made as large as possible 
and the lift is limited to from % Q to ^ in. 

The best materials for valve heads are cast-iron, nickel-steel, and 
tungsten-steel. Cast-iron is very cheap, easily worked, and stands 
corrosion well. It is weak, however, and therefore requires a heavier 
weight than other materials and this is especially objectionable for high- 
speed engines. The nickel-steel is strong, non-corrosive, and has a 
very low coefficient of heat expansion. Hence it does not warp so readily 



as other metals It is rather expensive and when used is generally 
electrically welded to a carbon-steel valve stem. The tungsten-steel is 
very hard and will stand high temperatures without pitting. Cast-iron 
valve heads can be screwed on a steel stem as in Fig. 40, the stem being 
riveted to prevent loosening. Figure 41 shows a common European form 

FIG. 42. T-head. 

FIG. 43. L-head. 

FIG. 44. I-head. 

FIG. 45. L-and-I head. 

for valves which is being rapidly adopted here. The curvature under- 
neath gives the gases a smooth passage without any of the whirling eddies 
that occur under the ordinary flat valve. 

Any valve needs regrinding into its seat occasionally with oil and 
emery or ground glass. Exhaust valves require this more often than 
inlet valves, as they become warped and pitted by the hot gases. After 



a valve is ground in, the push rods should be readjusted, as the grinding 
will lower the valve and reduce the clearance in the valve motion. 

28. Valve Arrangements. The possible arrangements of the valves 
in the cylinder are numerous. Figure 42 shows the T-head arrangement 
used in many of the large automobiles. This arrangement permits of a 
large valve and a low lift, and therefore makes a very quiet engine. Fig- 
ure 43 shows the L-type with both valves on one side. This is the most 
common type. It requires only one cam shaft and has a very simple, 


FIG. 46. Section of Silent Knight engine. 

direct-acting valve mechanism. It does not have as much cooling surface 
to the combustion chamber and is, therefore, more economical in the use 
of fuel than the T-head. Figure 44 shows the valve-in-the-head arrange- 
ment. This is sometimes called the I-head arrangement. It is especially 
popular for racing cars because it gives a short, quick passage into the 
combustion chamber and gives a simple, compact combustion chamber 
with a minimum loss of heat to the cooling water. Figure 45 shows an 
arrangement used on the Reo car that is a combination of the L-type 
and the valve-in-the-head type, the intake valve being in the top and 


operated by a rocker arm while the exhaust is on the side and is operated 
by a direct push rod. Both valves are operated from one cam shaft. 

29. The Knight Engine. The Knight engine is built on the principle 
of the four-stroke cycle, but the usual poppet valves have been replaced 
by two concentric sleeves sliding up and down between the piston and 
cylinder walls. Certain slots in these sleeves register with one another 
at proper intervals, producing direct openings into the combustion 
chamber from the exhaust and inlet ports. The construction of the 
Steams-Knight motor is illustrated in Fig. 46 which shows the general 
arrangement of the parts and their nomenclature. 

FIG. 47. Action of sleeves in Knight engine. 

It will be noted that two sleeves are independently operated by small 
connecting rods working from an eccentric or small crank shaft running 
lengthwise of the motor. This eccentric shaft is positively driven by 
a silent chain at one-half the speed of the crank shaft. The eccentric 
pin operating the inner sleeve is given a certain lead or advance over 
that operating the outer sleeve. This lead, together with the rota- 
tion of the eccentric shaft at half the crank-shaft speed, produces the 
valve action illustrated in Fig. 47, which shows the relative positions of 
the piston, sleeves, and cylinder ports at various points in the rotation of 
the crank shaft. 

30. The Rotary Valve. The rotary valve as used in the Speedwell 
car consists of two cylindrical shafts in the head of the motor, one for ex- 



haust and one for the inlet. These shafts are slotted and when rotating 
register with ports in the cylinder walls, thus opening passageways for 
intake and exhaust gases. The rotary movement of the valves is con- 
tinuous in one direction, the valves being driven by a silent chain from 
the crank shaft. Figure 48 illustrates the different positions of the 
rotary valves at the beginning of each of the four strokes. The arrows 
inside show the direction of rotation of the valves and the arrows out- 
side indicate the direction of the fresh gas going in and the exhaust gas 
passing out of the cylinder. 

31. Two-stroke Engines. Two-stroke engines as a class are not so 
flexible as the four-stroke engines under the varying speeds and loads 
encountered in automobile service. Consequently they have not been 
used to any great extent in motor cars, although a few satisfactory cars 
have been built with them. 



FIG. 48. Speedwell rotary valve engine. 


Since the piston of a four-stroke engine receives an impulse or ex- 
plosion only once in two revolutions, considerable effort has been ex- 
pended in trying to develop an automobile engine that would give an 
explosion in each cylinder every revolution and yet would operate as 
satisfactorily and economically as the four-stroke engine. An impulse 
every revolution would make a more powerful engine than one of the 
same size which received an impulse only once in two revolutions and it 
would also make the flow of power more continuous for the same number 
of cylinders. 

The Two-port Engine. Most of the two-stroke engines in use are very 
much like those shown in Figs. 49 to 52. In appearance, these engines 
are much simpler than the four-stroke engine, but are not necessarily 
any simpler in operation. They do not have any valves opening into the 
combustion chamber, such as are found in the four-stroke engine. The 
exhaust gases leave the cylinder through a port in the cylinder wall, which 
is uncovered by the piston at the end of the expansion stroke, as shown in 
Fig. 50. At the same time, a fresh charge is blown into the cylinder through 


a similar port on the other side. The top of the piston has a deflector 
which turns the incoming charge up into the clearance space. The 
charge then strikes the cylinder head, which turns it down on the other 
side toward the exhaust port, thus driving the dead gases out ahead of 
it. The piston then comes back, shuts off both these openings and 
compresses the fresh charge into the clearance space as shown in Fig. 
49. It is then ignited in the usual manner by a spark plug screwed into 
the cylinder head. This gives the piston an impulse every revolution. 

The engines of Figs. 49 to 52 have each crank enclosed all around 
and they use this case or chamber as a sort of a pump to supply fresh gas 
to the cylinder. When the piston goes up, the space inside the crank case 
is increased, and when it comes down the space is reduced, thus main- 
taining a breathing action inside the crank case. In Fig. 49 the piston 

Spark Plug 

Exhaust Port 
Transfer Port 
/ Check Valve (Open) jig 


Check Valve (Closed) 

FIG. 49. FIG. 50 

FIGS. 49 AND 50. Two-port, two-stroke engine. 

is shown traveling toward the top. This motion causes a suction in 
the crank case and causes air to enter through the carburetor. As the 
air passes through the carburetor it becomes saturated with gasoline and 
then passes through the check valve into the crank case. When the 
piston gets to the top, the suction ceases and the check valve is closed 
by its spring. Meanwhile, an explosive mixture has been compressed 
above the piston and at the top of the stroke is ignited by a spark. This 
produces an explosion or rise in pressure above the piston, just as in the 
four-stroke cycle and this drives the piston down on its working stroke. 
As the piston comes down, it compresses the fresh gases in the crank 
case into a smaller volume and thus raises their pressure. Meanwhile, 
as the piston nears the bottom of its stroke, it uncovers the exhaust port 
and the pressure in the cylinder causes a large part of the burned gases 



to shoot out through this port. An instant later the piston uncovers a 
transfer port on the other side and is now in the position shown in Fig. 
50. This transfer port is connected into the crank case and therefore allows 
the gases from the crank case to blow over into the cylinder as shown 
in Fig. 50. 

The piston head is so shaped as to form a deflector, which turns 
the fresh charge toward the cylinder head so that it can not blow out 
the exhaust port. The piston then returns, cuts off these ports, and 
compresses this charge, meanwhile drawing another charge into the 
crank case. This engine is called a two-port type, because there are only 
two ports in the cylinder walls to be operated by the piston. 

The Three-port Engine. The only difference between this type and 
the preceding one is in the method of admitting the gases into the crank 

Spark Plug 

Met Port 

Transfer Port 


Carburetor \-, 

FIG. 51. FIG. 52. 

FIGS. 51 AND 52. Three-port, two-stroke engine. 

case. Instead of using a check-valve, the admission of the gases' to the 
crank case is controlled by the piston, which uncovers a third port in the 
cylinder walls as it nears the top of the compression stroke. As will be 
seen in Fig. 51, the carburetor is on the other side of the engine, placed 
just below the exhaust pipe. As the piston rises, it creates a suction in 
the crank case, but there is no way for any gas to get in until the piston 
reaches the top of its stroke. As the piston uncovers this third port, the 
air enters with a rush through the carburetor, picks up the gasoline on its 
way through, and enters the crank case. The piston then descends, cuts 
off the third port, compresses the gases in the crank case, as in Fig. 52, 
and then blows them over into the cylinder as before. 

Against the two-stroke engine we have the facts found from ex- 
perience that they 'are not as economical in the use of fuel and are more 


uncertain in their action than the four-stroke engine. Since the fresh 
charge is depended on to blow out the exhaust gases, it is evident that 
some of the incoming charge is liable to pass out through the exhaust port. 
Gases mix very quickly and it is not possible to keep the dead and fresh 
gases separate, and yet drive the dead gases out and fill the cylinder com- 
pletely with fresh gases. If a full charge enters through the transfer 
port, some of it will be lost through the exhaust port without its being 
utilized. By skillfully proportioning the two ports and the shape of the 
deflector to the size and speed of the engine, it is possible to largely pre- 
vent the waste of fuel through the exhaust port. 

A two-stroke engine does not get as full a charge of gas as does a four- 
stroke engine and, consequently, will not be twice as powerful. The 
horse power of a two-stroke engine is usually about 1% to 1^ times that 
of a four-stroke engine of the same size and speed. 

The small two-stroke engines shown in Figs. 49 to 52 sometimes cause 
trouble from back-firing or exploding in the crank case. This is caused 
by the mixture in the crank case becoming ignited and exploding before 
it goes over into the cylinder. This wastes the energy of the gas and fills 
the crank case with dead gases, so that the engine will frequently come to 
a stop. Back-firing is caused by the mixture in the cylinder being still in 
flames when the piston uncovers the transfer port. The flame shoots 
through this port into the crank case and fires the mixture there. It has 
been found by experience that mixtures weak in gas are the ones which 
burn slowly and therefore cause back-firing. Consequently, the cure for 
crank-case explosions is to give the engine more fuel. 

Any leaks into the crank case are very serious in either of these 
types. With the slow speed used -in starting an engine by hand, a very 
small leak may admit air enough to satisfy the suction in the crank case 
and thus prevent any gas from being drawn in or, at any rate, it may so 
weaken the mixture as to make it non-explosive. 

This brief statement of some of the difficulties of the two-stroke engine 
will show some of the things that must be overcome in order to make this 
type of motor generally applicable to automobile service. 

32. The Flywheel. The purpose of the flywheel is to keep the engine 
running from one explosion to the next, and to make the engine run 
smoothly. If an engine did not have a flywheel, it would run in a very 
jerky manner, if it ran at all, and it is more probable that the explosion 
would simply drive the piston to the other end of the stroke and that it 
would stop there. Any one knows that the heavier a moving object is 
and the faster it is going, the harder it is to stop it. The flywheel on an 
engine is quite heavy and the result is that, once started, it will keep the 
engine going for some time. A gas-engine flywheel must not only be 
heavy enough to keep it going from one explosion to the next, but must 


keep it going without allowing the speed of the engine to drop down too 
much between explosions. 

33. Ignition. In order to cause the explosions within the cylinder, 
some means must be provided for lighting the charge of gas. This is 
usually done by causing an electric spark to pass between two points 
within the cylinder. The spark sets fire to the mixture and the explosion 

There are two general methods of electric ignition. One of these is 
called the make-and-break system because it requires some moving 
parts inside the cylinder to make an electric circuit, and then break it 
quickly so that a spark will occur inside the cylinder. The other system 
is called the jump-spark system. This is the system used in automo- 
biles. There are no moving parts which have to pass through the cylinder 
wall in this system. The spark coil or magneto makes a current powerful 
enough to jump between two fixed points inside the cylinder. The 
complete details of these systems of ignition will be taken up in a later 

34. Clearance and Compression. It was discovered by some of the 
early inventors of gas engines that compressing a gaseous mixture causes 
it to give a much more powerful explosion. Consequently, all gas engines 
draw in a full cylinder charge of gas and air, and then compress this back 
into a space left at the upper or rear end of the cylinder. This space, 
which is left for the gas to occupy when the piston is at the top end of its 
stroke, is called the clearance space or combustion chamber. The amount 
of this clearance space in relation to the whole cylinder volume determines 
just how much the gas is compressed. It has been found from experience 
that different kinds of gases require different amounts of compression and, 
therefore, the clearance space is made different for different fuels. The 
clearance is generally spoken of as being a certain per cent, of the piston 
displacement, varying from 24 to 30 per cent, for automobile engines. 

35. Piston Displacement. This refers to the space swept through by 
the piston in going from one end of the stroke to the other. It is given 
this name because, as the piston moves through its stroke, it will either 
draw in or force out that volume of air or gas. The piston displacement 
is calculated by multiplying the length of stroke by the area of a circle 
whose diameter is the inside diameter of the cylinder. For example, a 
3j^-in by 5-in. engine (this means 33^ in. inside cylinder diameter and 
5 in. stroke) would have a piston displacement as follows: 

The area of a 3^-in. circle is 0.7854 X 3>^ X 3> = 9.621 sq. in. 

The piston displacement is 5 times this, or 48.105 cu. in. 

The clearance of such an engine would be from 24 to 30 per cent, 
of this. If we suppose that it is 25 per cent., then the actual space which 
must be left for the clearance will be 48.105 X 0.25 = 12.026 cu. in. 


36. Cylinder Cooling. When an explosion occurs inside the cylinder 
of an engine, the gases on the inside reach a temperature somewhere 
around 3000. The walls of the cylinder are, of course, exposed to this 
high heat and would very quickly get red hot if we did not have some way 
of keeping them cool. The polished surface upon which the piston slides 
would be very quickly spoiled. The most common way of keeping the 
cylinder cool is by the use of water, and the arrangement for this is shown 
in the engines illustrated in this chapter. Surrounding the cylinder is a 
jacket with a space between for the cooling water. By keeping a supply 
of water passing through this space, the cylinder can be kept cool enough 
for the operation of the engine. The cylinder head is also cast with a 
double wall, especially around the valves, so that these parts will also be 
kept cool. The cooling fluid used is generally water, although sometimes 
special anti-freezing solutions are used where there is danger of the 
engine freezing. Water should not be allowed to remain in the jacket of 
an engine over night if there is danger of a frost, as the freezing of the 
water will crack the cylinder. When the supply of water is limited, as 
in an automobile, the water is cooled in a radiator or system of pipes, and 
used over again. The water is kept in circulation by a pump or by the 
thermo-syphon system and the hot water is cooled by the air passing over 
the radiator. 

37. The Muffler. When the exhaust valve of an engine opens at the 
end of the expansion stroke the pressure of the gas inside the cylinder is 

FIG. 53. Typical muffler. 

still about 50 or 60 Ib. per square inch. The valve must open and let 
this pressure out before the piston starts back, or else the back pressure 
will tend to stop the engine. The valve is opened quickly, and the high 
pressure, being suddenly released into the exhaust pipe, causes the 
sharp sound which we hear when an engine exhausts. This sound is not 
the sound of the explosion, as is commonly supposed. The real ex- 
plosion takes place a little before this sound and can be heard only as a 
dull thump inside the cylinder. The explosion occurs at the beginning 
of the working stroke, while the sound that we hear in the exhaust comes 
at the end of the stroke. 

In order to prevent this sudden exhaust from causing too great a 


noise it is customary to have a muffler. A muffler is generally a chamber 
in the exhaust pipe which receives the exhaust gases from the engine and 
expands them gradually into the outside air, thus preventing a loud 
noise. A common arrangement of an automobile muffler is shown in 
Fig. 53. 

38. Horse Power of Engines. The horse power of an engine is 
the measure of the rate at which it can do work. One horse power is 
a rate of 33,000 ft.-lb. a minute. There are two ways of measuring 
engine power. We can determine the power developed by the ex- 
plosions in the cylinder, in which case we have what is called the indi- 
cated horse power (i.hp.} ; or we can attach a brake to the flywheel and 
measure the power which the engine actually delivers. This is called 
the brake horse power (b.hp.). Engines are usually rated by their brake 
horse power because that is what they are actually capable of delivering. 
The brake horse power of an automobile engine will usually be from 70 
to 85 per cent, of its indicated horse power, the loss being that consumed 
in the engine mechanism. 

There are a number of quick rules for estimating the power of engines 
according to their cylinder dimensions and the speed. Those most 
used for four-stroke engines are given below. The simplest of these and 
the one most used is known as the S. A. E. formula or Society of Auto- 
mobile Engineers formula. 

Authority Formula 

S. A. E. 1 D 2 N 

= hp. 

Royal Auto Club 2.5 

Brit. Inst. of Auto Engrs. 0.45 (D + L) (D - 1.18) = hp. 

D 2 7 7? AT 
E. W. Roberts -- = hp. 

D = diameter of cylinder in inches. R = revolutions per minute of 

crank shaft. 
L = length of stroke in inches. N = number of cylinders. 

Derivation of the S. A. E. Horse Power Formula. The indicated horse 
power of a single-cylinder, four-stroke engine is equal to the mean ef- 
fective pressure, P, acting throughout the working stroke, times the area 
of the piston, A, in square inches, times one-quarter times the piston speed, 
S, divided by 33,000, thus: 

~ 33,000 X 4 

Multiplying this by the number of cylinders, N, gives the indicated 
horse power for an engine of the given number of cylinders, and further 
multiplying by the mechanical efficiency of the engine, E, gives the 
brake horse power. 



Therefore, the complete equation for brake horse power reads: 

b.hp. - 33 ^ 000 x 4 

The S. A. E. formula assumes that all motor car engines would de- 
liver or should deliver their rated power at a piston speed of 1000 ft. 
per minute, that the mean effective pressure in such engine cylinders 
would average 90 Ib. per square inch, and that the mechanical efficiency 
would average 75 per cent. 

Substituting these values in the above brake horse power equation, 
and substituting for A its equivalent, 0.7854Z) 2 , the equation reads: 

90 X 0.7854P 2 X 1000 X N X 0.75 
33,000 X 4 

and combining the numerical values it reduces to: 

To make it simpler, the denominator has been changed to 2.5 without 
materially changing the results. 

The formula can be simplified, however, for ordinary use by consider- 
ing the number of cylinders; thus for the usual four-, six-, and eight- 
cylinder engines it becomes: 

1.6 D 2 = hp. for all four-cylinder motors. 

2.4 D 2 = hp. for all six-cylinder motors. 

3.2 D 2 = hp. for all eight-cylinder motors. 

4.8 D 2 = hp. for all twelve-cylinder motors. 

The S. A. E. formula comes very close to the actual horse power 
delivered by most automobile engines at the piston speed of 1000 ft. 
per minute. However, at the present time, most of the engines will 
deliver the maximum power at speeds higher than this, usually around 
1500 ft. per minute. As a result, the power which the engines are capable 
of delivering is greater than that given by the S. A. E. formula. The 
formula will serve, however, as a means of comparing engines on a uniform 



39. Single- and Multi-cylinder Engines. The first automobile power 
plant consisted of a one-cylinder engine which gave power impulses at 
regular intervals of time for the propulsion of the car. Naturally it 
operated very jerkily and with considerable noise, due to the size of the 
cylinder and the time between impulses. These facts led to the adoption 

-Two Revolutions- 


1 Cylinder 

2 Cylinders 

4 Cylinders 

6 Cylinders 

8 Cylinders 

FIG. 54. Power diagrams. 

of the two-, four-, and six-cylinder engines, and quite recently the eight- and 
twelve-cylinder engines have come into use as automobile power plants. 
In Fig. 54 can be seen one of the distinct advantages of the multi- 
cylinder engine for motor car purposes. The length of the diagram 
represents two revolutions of the engine crank shaft. The curved line 
7 43 


acefg represents the variations in the power from a single cylinder. The 
line bh represents uniform power requirement of the car. When the 
power curve goes above bh the engine accelerates and the surplus power 
is thus stored in the flywheel; when the curve goes below bh the flywheel 
gives up power and the engine slows down. 

As the number of cylinders increases, the impulses increase in fre- 
quency, the average power is greater, and above four cylinders there is 
no period during which some cylinder is not delivering power. This 
means that in a six- or eight-cylinder car, there is no time at which the 
flywheel must supply all the power required by the car. 

The multi-cylinder engine, therefore, furnishes a practically continu- 
ous flow of power to the car with little vibration. The increase in the 
number of cylinders has a tendency to reduce the size of each cylinder 
and this fact combined with the steady operation of the engine, makes the 
modern automobile engine a very smooth-running, quiet, power-plant 

40. Power Plant and Transmission Arrangements. Figure 55 shows 
the arrangement of the Studebaker power plant and transmission system. 
The engine is placed in the front of the frame, being supported at four 
points. The clutch, which is of the cone type, is built inside the flywheel, 
and permits the engine to be disengaged from the transmission system. 
The propeller shaft, which transmits the power from the engine to rear 
wheels, is connected to the clutch by means of a universal joint which 
permits the shaft to receive power and to deliver it to the rear axle. 

The change-gear set or transmission is placed on the rear axle just in 
front of the differential housing which carries the differential gear. The 
change-gear set permits the relative speed of the engine and car to be 
changed according to conditions. The chassis diagram indicates the 
location of the other important parts. Notice the three-quarter elliptic 
rear springs. 

The chassis of the Mitchell "Eight" is shown in Fig. 56. The engine 
in this case is supported at only three points, one at the front and two at 
the rear. The clutch is of the cone type operating in connection with the 
flywheel. It will also be noticed that the change-gear set is placed at the 
front of the propeller shaft, which then goes directly to the final drive 
on the rear axle. There is a single universal joint, which is between the 
clutch and gear set. 

The Hollier " Eight" chassis is shown in Fig. 57. Here we see the 
application of the well-known "unit power plant" in which engine, 
clutch, and change gears are built into one single unit. This arrangement 
permits the use of only one universal joint between power plant and rear 
axle. Notice the cantilever type of rear springs. 

In the chassis of the Ford Model T, Fig. 58, use is also made of the 



~~Un/ verso/ 
,' Joints 

FIG. 55. Chassis of Studebaker "Six, 



FIG, 56, Chassis of Mitchell "Eight 




FIG. 57. Chassis of Hollier "Eight." 


"unit power plant" with three-point support. The engine, clutch, and 
change gears are built together in a single unit and are supported on the 
frame at only three points. The connection between power plant 
and rear axle is made by the use of only one universal joint. As will be 
seen later, this car is equipped with a "planetary" transmission which is 
built on a principle entirely different from the usual clutches and change- 
gear sets. The entire rear of the car is supported by an inverted semi- 

Tic. 58. Chassis of Ford Model T. 

elliptic spring extending over the rear axle. A similar but lighter 
spring is used in front. 

The sectional view of the Lyons-Knight four-cylinder car in Fig. 59 
shows very clearly the arrangement of the engine and the transmission 
groups. The engine is of the Knight type and delivers its power through 
a plate clutch and through the universal joints and propeller shaft to the 





change gear set built on the rear axle. The final drive from shaft to axle 
is of the worm type which will be discussed later in the chapter. The 
clutch control pedal and the change gear control lever are outlined very 

41. Modern Automobile Power Plants. The automobile power plant 
includes the engine and all accessories necessary for the production of 
power. The transmission system includes the mechanism necessary for 
taking this power furnished by the power plant and transmitting it to the 
rear wheels. 

In most cases, the power plant includes the engine and its component 
parts such as carburetor, ignition devices, cooling system, etc. and the 

Hot water outlet-,^ 

Air heater 

Co/a 1 water 

Cone -~ 

'ater supply 
to pump 

Water pump 

FIG. 60. Four-cylinder Wisconsin engine. 

transmission system includes the clutch, change gears, universal joints, 
differential, and rear axle. When the unit power plant is used, it includes 
in addition to the engine and its essential component parts, the clutch and 
the change gears. 

Four-cylinder Power PZante. Figure 60 illustrates a typical four- 
cylinder automobile engine with the essential parts indicated. The view 
shown is the exhaust side of the motor, it having the T-head valve arrange- 
ment. The cylinders are cast in pairs, two cylinders being in each unit, 
he water jackets are cast integral with the cylinders. The water con- 
itions at the top and bottom of each casting are indicated. The clutch, 



Sfar~f/'n(j motot generator- 

FIG. 61. The 1914 Cadillac engine. 



FIG. 62. Studebaker "Four" engine. 

FIG. 63. Section of Buda engine. 


III 1 1 



one member of which is machined in the engine flywheel, is of the cone 
type, this being the customary method of applying the cone clutch to the 

The engine of the 1914 Cadillac is illustrated from both sides in Fig. 61 
s of the L-head type, having both intake and exhaust manifolds on 


the right side. The most prominent feature of this engine is that the 
cylinders are cast singly with copper water jackets fastened securely 
around the castings. The single-cylinder castings necessitate a longer 
engine than if cast in pairs or en bloc, but they also make the renewal 
expense less if a single cylinder is damaged. 

Figure 62 is a right-side view of the Studebaker "Four" engine, 
showing the en bloc cylinder construction, in which all cylinders are cast 
in one piece. This permits the engine to be much shorter than when 
cast in any other way. The structure is also more rigid, and can be 
made considerably lighter than when cast singly. 

wafer oaf/ef 
Removable, cylinder \ 

head \ ft j. connection 

one clutch Cy/inc/ers cast en- bloc 

FIG. 66. Power plant of MitcheU "Six." 

The sectional view of a Buda Model T engine in Fig. 63 shows very 
clearly the internal construction of an engine. This engine is of the 
L-head type with only one cam shaft. The crank shaft is of the con- 
ventional three-bearing type, i.e., with a bearing at each end and one 
at the center. 

The Ford unit power plant is shown in section in Fig. 64 with all 
parts fully designated. The magneto, change gears and clutching ar- 
rangement are of considerable interest and will be discussed under the 
proper headings. As will be remembered, this power plant has three- 
point support. 



Six-cylinder Power Plants. The Jeffrey six-cylinder power plant 
is shown in section in Fig. 65. The cylinders are cast in pairs, thus 
permitting the use of a four-bearing crank shaft. In the pair of cylinders 
at the left, the section is taken through the valves so as to show the cams, 
push rods, springs, and valves. The center pair is sectioned through 
the center of the cylinders so as to show the pistons, pins, and con- 
necting rods. The valve arrangement is of the L-head type. 

The engine of the "Mitchell Six of '16," Fig. 66, has the six cylinders 
cast "en bloc," which gives a very compact and rigid construction of 
pleasing appearance. The cylinder head can be removed in one piece for 
the purpose of cylinder and valve examination. 

The Franklin motor, Fig. 67, represents a very interesting and 
unique design, having overhead valves and air-cooling. The cylinders 
are cast singly and each is air cooled by a system of cast ribs and air 
cooling, doing away with the water jackets around the cylinders. The 

FIG. 67. The Franklin air-cooled engine. 

air is drawn downward around the cylinder ribs by the suction of the 
flywheel fan. 

42. Constructional Features of Four- and Six-cylinder Engines. The 
essential differences of construction in the various four- and six-cylinder 
engines, outside of the methods of cylinder construction and valve arrange- 
ment, consist in the construction and arrangement of the cam and crank 
shafts. Figure 68 is a conventional four-cylinder crank shaft, shown with 
connecting rods and pistons attached. There are three main bearings, 
as indicated. The connecting rod bearings are all in the same plane, bear- 
ings Nos. 1 and 4 being just 180 from Nos. 2 and 3. This means that 
the Nos. 1 and 4 pistons are in the same position in the cylinders at the 
same time. Likewise Nos. 2 and 3 are in the same position. If No. 1 
piston is on the compression stroke, No. 4 must necessarily be on the 
exhaust stroke and Nos. 2 and 3 on the suction and explosion strokes, 



The order of firing in a four-cylinder engine must be in the order 1, 3, 
4, 2 or 1, 2, 4, 3. 

The five-bearing crank shaft for a four-cylinder engine has main bear- 
ings between all the cranks. Figure 69 shows the five-bearing crank shaft 

FIG. 68. Three-bearing, four-cylinder crank shaft. 

in place on the 1914 Cadillac four-cylinder engine. This type of crank- 
shaft construction is especially adapted to an engine with individually 
cast cylinders. 

Chain drive for- 

ajneto & oump 

FIG. 69. Five-bearing, four-cylinder crank shaft in position. 

The crank shaft for a six-cylinder engine is arranged as shown in Fig. 
70. Cranks 1 and 6, 2 and 5, 3 and 4 are in pairs and are spaced 120 



apart. The pistons in the paired cylinders are always in the same relative 
positions in the cylinders. The firing order of the cylinders is usually 1, 
5, 3, 6, 2, 4 or 1, 2, 3, 6, 5,4. This crank has four main bearings. The 







FIG. 70. Four-bearing, six-cylinder crank shaft. 

shaft shown in Fig. 71 has only three main bearings. The arrangement 
of the cranks is the same as in the previous case. 

Matn bearings 

FIG. 71. Three-bearing, six-cylinder crank shaft. 

In Figs. 72 and 73 are illustrated the two general methods of cam shaft 
construction. Figure 72 is a one-piece cam shaft, the cams and shaft 

Fia. 72. One-piece cam shaft. 

being made of one solid bar of steel. This is the more common method of 
construction. The assembled cam shaft, Fig. 73, on which the individual 
cams are pinned or keyed is used at present in very few cases. The ob- 



jection to this type of shaft is that the cams may become loose on the 
shaft and give considerable trouble. For an L-head engine, a single cam 
shaft on one side of the engine carries both inlet and exhaust cams. For 

FIG. 73. Assembled cam shaft. 

FIG. 74. Cadillac eight-cylinder V-type engine. 

a T-head engine, however, one cam shaft carries the inlet cams on one side 
of the engine and another shaft carries the exhaust cams on the other side 


The cam shafts are driven at one-half crank shaft speed. The drive 
can either be by a silent chain, such as shown for the 1914 Cadillac in Fig. 
69, by spur gears such as in the Ford Model T shown in Fig. 64, or by 
helical gears such as shown in Figs. 72 and 73. 

43. Eight- and Twelve-cylinder Power Plants. In the four-cylinder 
engine, there is a power stroke every one-half revolution, but during a 
small interval at the end of each power stroke no power is being delivered 
by the engine. This means short periods in the operation of the engine in 
which the flywheel must supply all the power. In the six-cylinder engine, 

FIG. 75. Sectional view of Cadillac eight-cylinder engine. 

there is a power stroke every one-third revolution and, as a result, there is 
an overlapping and a more continuous flow of power (see Fig. 54). The 
impulses come oftener and, consequently, reduce the vibration. The 
same effect is carried further in the eight-cylinder engine which gives a 
power stroke every one-fourth revolution. The parts are considerably 
lighter and this aids in reducing the vibration. Most of the eight-cylinder 
engines are built in the V-type and this method of construction adds to the 
smoothness of operation. 

Cadillac Eight-cylinder Engine. Figure 74 is a front-end view of the 
Cadillac eight-cylinder engine. The cylinders are arranged in blocks of 



four each, placed in a V-shape at an angle of 90. A cross section of two 
opposite cylinders is shown in Fig. 75. The engine is of the L-head type 
with the valves on the inside of the V. One cam shaft placed directly 
above the crank shaft operates all of the sixteen valves by means of the 
rockers as shown. Eight cams serve to operate the sixteen valves, as 

FIG. 76. A pair of Cadillac connecting rods. 

FIG. 77. 

one cam operates a valve in each group. The cam shaft is carried by five 
bearings and has a silent chain drive as shown in Fig. 74. 

The crank shaft is like a conventional four-cylinder shaft with three 
main bearings. There are only four crank pins, two connecting rods, one 
from each group, bearing on the same crank. One of the rods, Fig. 76, 
is forked, while the other is perfectly straight, fitting in between the fork. 
The split bearing shown at the right fits directly over the pin. The forked 



rod fits over this bearing and is pinned to it, so that the rod and bearing 
work together. The other rod fits in the center surface of the bearing and 


FIG. 78. Top view of Mitchell "Eight" engine. 

FIG. 79. Front view of Mitchell "Eight" engine. 

runs on it. The arrangements permit the length of the crank shaft to be 
no greater than in a four-cylinder engine. 



The order of firing of the eight cylinders alternates from one side to 
the other. If the cylinders be numbered as shown in Fig. 77 the firing 
order is as follows: 1-L, 2-R, 3-L, 1-R, 4-L, 3-R, 2-L, and 4-R. The horse 
power rating of the Cadillac Eight is 31.25 according to the S. A. E. 
formula. On dynamometer test, however, it has developed 70 hp. at a 
speed of 2400 r.p.m. 

Mitchell Eight. The Mitchell Eight is constructed on the same gen- 
eral principle as the type previously mentioned. The cylinder groups are 
placed in a V of 90. The valves are placed on the inside of the V and 

FIG. 80. Engine of Packard "Twin Six." 

are operated by means of eight cams on a single cam shaft mounted above 
the crank shaft. The cylinders are slightly staggered and two connecting 
rods are mounted side by side on each crank instead of using the forked 

The engine is rated at 48 hp. The cylinders are 3-in. bore by 5^- 
in. stroke. The top and front-end views are shown in Figs. 78 and 79. 

The Packard Twelve-cylinder Engine. The twelve-cylinder unit power 
plant of the Packard car is shown in Fig. 80. The twelve cylinders are 
cast in two blocks of six, arranged in V-type with an included angle of 60. 
The cylinders have a 3-in. bore and a 5-in. stroke with L-head valve ar- 
rangement. The left block of cylinders is set forward of the right set by 



\Y in. in order to permit the lower end of the connecting rods of opposite 
cylinders to be placed side by side on the same crank pin. In addition, 
this arrangement permits the use of a separate cam for each valve, 
making 24 cams on the cam shaft. The single cam shaft is placed directly 
above the crank shaft. The crank shaft is of the usual six-cylinder type 
supported by three main bearings. 

Advantages Claimed for Eight- and Twelve-cylinder Motors. The chief 
advantages claimed by the eight- and twelve-cylinder motors are smooth 
running, lack of vibration, rapidity of pick-up, and wide range of activity 


Clutch teathej 

Clutch cone 

Clutch release 
r/ny - \ 

Transmission \ 

Clutch qear--*\ 

Clutch brake 

Clufch thrust bearing- 

C/ufch spring 

Crank shaft-- 

FIG. 81. Buick cone clutch. 

on high gear. It is possible with either of these types to run almost 
entirely on high speed under all conditions. 

44. Clutches. The gasoline engine must be set in motion before it 
will take up its cycle and generate power. This fact prevents it from being 
started under load and, consequently, means must be provided for de- 
taching the engine from the rest of the mechanism for starting before the 
load is thrown on. This mechanism for detaching the engine from the 
remaining part of the power and transmission system is called the 
"clutch." There are in use at the present time two general types of 
clutches, the cone type and the disc type. 

The Cone Clutch. Figure 81 illustrates the cone clutch as used in the 
Buick car. It consists of a leather-faced aluminum cone which is held 


tightly against the inside of the tapered rim of the flywheel by four springs 
carried on a spider. The aluminum cone is mounted on a steel sleeve 
which can slide back and forth on the clutch gear shaft to disengage or 
engage the cone with the flywheel. A grooved ring at the rear end of the 
sleeve connects the clutch to the clutch pedal. A small brake, attached 
to the transmission case, serves to keep the clutch from spinning after it 
is released. Four small spring plungers, located under the leather, force 
it out at these points and prevent grabbing when the clutch is let in. 

In operation, pressure on the clutch pedal is transmitted by a con- 
necting link and clutch release shaft to the yoke operating on the ball- 
bearing release ring, which pulls the clutch back out of engagement with 
the flywheel. The small brake now holds the clutch stationary, while 
the clutch spider and springs continue to turn with the flywheel until the 
clutch is again engaged. When in full engagement, the clutch and fly- 
wheel turn as a unit, transmitting the power through the gear set to the 
rear axle. 

Multiple Disc Clutches. The multiple disc clutch is built in two types 
the dry plate and wet plate. Figure 82 is a sectional view of the dry 
plate type of clutch as used on the Hudson. It consists of a series of 
alternate driving and driven discs. The driving discs receive their power 
from the flywheel by four studs, one of which shows in the cut. These 
discs are steel stampings. 

The driven discs are also steel stampings but are somewhat thicker 
and have holes into which cork inserts are pressed. The driven discs 
drive the inner drum by means of a series of grooves or slots. 

The driven and driving discs are pressed together by the clutch spring 
shown. When it is desired to release the clutch, the foot pedal compresses 
the clutch spring and the plates separate, permitting the driving members 
to run independently of the driven members. As -in all clutches, the 
power is transmitted entirely through a frictional contact. The cork 
inserts are used because they are soft and at the same time have a great 
adhesive property, even if they become soaked with oil. The advantage 
of this type of clutching arrangement is that a large frictional surface can 
be obtained with a comparatively small clutch diameter. In the cone 
type this diameter must necessarily be large in order to get the necessary 
friction surface on the one surface in contact. In letting in the plain cone 
type of clutch, there is also the possibility of a more sudden engagement 
than with the multiple disc type. This has been overcome by the use of 
the springs under the leather, as shown in Fig. 81. 

The wet plate clutch is constructed on the same general principles as 
the dry plate clutch, the essential difference being that it runs in a bath of 
oil. When the clutch is released, an oil film covers the entire surface of 
the plates and, when the clutch is thrown in, this film of oil is gradually 


squeezed out, permitting a very easy and gradual engagement. In the 
winter time, the oil may be unusually heavy and this prevents a quick 
engagement. This can be overcome by thinning the clutch oil with 

FIG. 82. Hudson dry plate clutch. 

45. Change Gear Sets. The change gear set is for the purpose of 
permitting different speed ratios between the engine and the car. When 
starting, the engine must run comparatively fast and the car slow. 
When the car gets under way, the relative speed of car and engine must be 
changed in order to get efficient operation. 

Figure 83 is the gear set used on the Jeffrey car. The right shaft is 
driven by the clutch; attached to this shaft is the drive gear which at 
all time drives the lay-shaft drive gear fastened to the lay-shaft. The lay 
shaft in addition carries four fixed gears as shown. The main drive 
shaft has one end bearing rotating within the main drive gear. Con- 
sequently the drive gear and main shaft can run independently of each 
other. The main shaft carries two sets of sliding gears, the names and 
purposes of which are indicated. These two sets are operated by two 



shifter yokes which lead to the gear control lever in the car. This gear 
set provides four forward speeds and a reverse speed. This type is 
known as the "selective sliding gear set," because, as the name in- 
dicates, any one of the speeds can be selected at will, in contrast to the 
"progressive sliding gear set" in which the speeds must be taken in 

Figure 84 illustrates the gear positions for the various speeds obtained 
in the Studebaker three-speed-and-reverse gear set. The white arrows 
indicate the gears through which the power is transmitted for the different 



FIG. 83. Jeffrey gear set. 

46. Planetary Gearing. This type of combined clutch and change 
gears, such as used on the Ford Model T, is especially adapted to light 
cars in which two forward speeds are sufficient. The gears are not shifted 
into or out of mesh for the different speeds, as in the sliding gear set, but 
they are always in mesh, as shown in Fig. 85. On high gear, the entire 
mechanism is clamped solidly together by the clutch and revolves as a 
single mass with the flywheel. The clutch is of the multiple disc type, 
running in oil. The flywheel has three studs, each of which carries three 
gears of different sizes fastened together to form what is called a "triple 
gear." These triple gears mesh with three gears of different sizes in line 
with the engine shaft. The inner one, next to the flywheel face, is fast- 










FIG. 84. Positions of gears in Studebaker three-speed-and-reverse gear set. 



ened to the drive shaft which delivers the power through to the rear axle. 
The other two central gears float on the drive shaft and are connected 
to the two drums nearest to the engine. Surrounding these drums, but 
not shown in the figure, are brake bands which can be tightened by foot 
pedals. These can be seen in Fig. 64. If the slow-speed drum is gripped, 
the second of the three central gears will be held stationary. This makes 
the triple gears rotate on their studs as the flywheel revolves. In doing 
this, they drive the inner central gear, or the driving gear, slowly forward, 

FIG. 85. Ford planetary transmission. 

due to the differences in the sizes of the gears. If the middle drum is 
gripped instead, by pushing on the reverse pedal, the larger of the central 
gears is held. This makes the triple gears revolve again on their studs as 
the flywheel revolves, but since this reverse gear is larger than the drive 
gear, the motion of these triple gears will turn the drive gear slowly back- 
ward. For high speed, the entire mechanism is gripped solidly together 
so that it revolves at engine speed. The third drum is used for a service 

47. Universal Joints and Drive Shaft. The use of one or more univer- 
sal joints between the power plant and the rear axle is necessary, as can 
be seen in Fig. 59, in order to provide for the lower position of the rear 
axle and also to allow for the spring action between the axle and the frame 
which carries the power plant. The universal joint permits this to be 
done with very little loss of power. Figure 86 shows the propeller shaft 
or drive shaft of the Jeffrey car with its universal joints. A square block 
in the center of the universal joint fits between the jaws of two forks, one 
of which is connected to the power plant and the other is attached to the 



end of the drive shaft. The flexible connection of these forks to the block 
permits the drive shaft to oscillate freely with the rear axle and yet con- 
tinue to receive and transmit power. 




FIG. 86. Jeffrey propeller shaft and universal joints. 

48. Final Drive. The final drive to the rear axle is accomplished by 
means of bevel, spiral-bevel, or worm gearing. The direction of the power 
transmission must be changed through a right angle at this point. 
Figure 87 shows the bevel gear final drive as used on the Jeffrey car. Both 
the bevel pinion and the differential housing which carries the driving gear 
or ring gear are carried by ball bearings. The action of the bevel gears 

FIG. 87. Jeffrey final drive. 

produces a side thrust, caused by the inclination of the faces of the teeth, 
tending to separate the gears. This makes it necessary that the bearings 
of these gears be capable of resisting this thrust. Either ball bearings or 
tapered roller bearings are employed. If the straight rollers are used for 
bearings, special thrust bearings must be provided. 

"Figure 88 shows a spiral-bevel gear drive with the Timken tapered 



roller bearings, as used on the Cadillac car. The chief claims for the 
spiral-bevel drive are that the spiral teeth give a more continuous driving 
action between the teeth and overcome any possible inaccuracies in the 
teeth or any tendencies to wear irregularly; also that they overcome the 
thrust, to a more or less extent, by producing a counteracting pull. 

Fig. 89 shows the worm drive to the rear axle. This has the worm 
placed above the gear. The worm drive in Fig. 59 shows one with the 

worm placed underneath. The worm 
drive is very quiet running, but requires 
careful lubrication because of the con- 
stant sliding action between the teeth of 
the worm and gear. One of the two 
gears should run in an oil bath. The 
worm drive is especially popular in 

FIG. 88. Cadillac spiral-bevel 

FIG. 89. Worm drive used on Jeffrey 
"Chesterfield Six." 

heavy truck service where there is a large reduction in speed. The 
worm is generally made of steel and the gear of bronze to keep down the 

49. Types of Live Rear Axles. The dead rear axle was illustrated and 
explained in Chap. I. The live axle is used on practically all makes of 
pleasure cars, with only one or two exceptions. Live rear axles are clas- 
sified according to their methods of construction as simple, semi-floating, 
three-quarter floating, and full floating. 

Simple Live Axle. The simple live axle used on the Ford Model T is 
shown in Fig. 90. This type of rear axle performs two functions in that 
it carries the entire weight of the rear of the car in addition to transmitting 
the power. The rear wheel is keyed to the axle as shown. The weight 



is carried by roller bearings directly on the live axles both at the wheel and 
differential ends. 

Semi- floating Axle. Figure 91 is of the semi-floating type and shows 


the essential difference between a simple and semi-floating live axle. In 

the semi-floating axle the inner bearings are carried on an extension of the, thus relieving this end of the live axle of considerable 


stress. The wheel as in the other case is keyed to the axle. The con- 
struction at the outer end of the semi-floating axle is the same as in the 
simple axle. In either of these types the weight of the car produces a 
bending stress in the axle. 

Three-quarter Floating Axle. Figure 92 shows the change in this type 
of construction from the semi-floating type. The weight is carried by the 
bearings on the housing and directly in line with the spokes, thus re- 
lieving the axle of all bearing stresses. The wheel is keyed onto the shaft. 

FIG. 91. Semi-floating rear axle. 

Although in the three-quarter type the live axle is relieved of all weight, 
nevertheless the bending strains due to a possible side movement of the 
wheel, or the distortion due to a bent housing are still thrown on the axle 
due to the fact that the wheel is keyed onto the axle. Also, in this type, 
if the live axle breaks, the wheel can come off and let the car drop. This 
is prevented only by the full-floating construction. 

Full-floating Rear Axles. Figure 93 shows the full-floating construc- 
tion as used on the Buick car. The wheel is carried on a double ball or 
roller bearing on the axle housing, in such a way as to retain the wheel 
on the housing regardless of what may happen to the live axle. In this 
construction, the live shaft receives only the torsional strains of driving 
the car, all other loads being taken by the axle housing. The live shaft 
may be removed and replaced without disturbing either the wheel or the 



differential. The inner ends of the axle shafts are grooved and slide into 
corresponding grooves in the differential gears. The entire drive shaft 
on either side may be removed by merely removing a hub cap and sliding 
the shaft out. In the form shown in Fig. 93, the shaft is keyed into the 

FIG. 92. Three-quarter floating axle construction. 








FIG. 93. Buick full-floating rear axle. 

hub cap. In another form, the outer end of the shaft has a toothed clutch 
which fits into corresponding recesses in the outer face of the hub. This 
permits a certain amount of play and relieves the shaft from any distor- 
tion if the axle housing becomes bent. 


One of the most important operations in a gas engine is that of getting 
an explosive mixture inside of the engine cylinder at the proper time. This 
explosive mixture is formed by the thorough mixing of air and a gas 
formed by the evaporation of a volatile liquid fuel, usually gasoline. 

50. Hydrocarbon Oils. Most of the liquid fuels are known as 
"hydrocarbon" oils, because they are made from crude mineral oil con- 
taining as its principal parts, hydrogen and carbon. One of the hydro- 
carbon fuels, viz., alcohol, is not of mineral derivation, but is made by 
the distillation of vegetable matter. 

The crude oil or petroleum from which the hydrocarbon fuels are 
made is found in natural deposits several hundred feet below the earth's 
surface. In some places it has to be pumped out, while in others it is 
forced out by natural gas pressure. Most of the crude oil found in the 
United States comes from Pennsylvania, Ohio, Illinois, Kansas, Texas, 
Oklahoma and California. These crude oils are of two general types, 
that coming from Texas, Oklahoma, and California having what is known 
as an "asphalt" base, and that from Pennsylvania and Ohio having a 
"paraffin" base. Crude oil having an "asphalt" base is a heavy dark 
liquid, which when boiled, leaves a black tarry residue. If the crude oil 
has a "paraffin" base, it is much lighter in weight and color and, when 
boiled, leaves a residue from which is made the white paraffin or wax with 
which everyone is familiar. 

Formerly, gasoline made from crude oil with a paraffin base was sup- 
posed to be of a higher grade than the other, but with the modern proc- 
esses of refining, the gasoline from the two kinds of crude oil gives equally 
good results. 

51. Fractional Distillation of Petroleum. The crude oil is heated in 
large retorts or "stills," provided with accurate temperature recording 
devices. When the temperature has reached about 100F. a vapor be- 
gins to rise from the oil. This vapor is collected from the top of the retort 
and condensed in cooling coils, from which the liquid is collected in vessels. 
As the temperature in the retort rises, the vapor becomes heavier and, 
when condensed, gives the heavier and less volatile liquid fuels. The 
following table gives, approximately, the products of this method of 
distillation : 



Distilling at IOOF to I25F 
Hiqhly Volatile oils -qasoline, 
benzine, naphtha, ICTtolB%. 

Distilling at 125* F to 350*F. 
Kerosene and light lubricat- 
ing oils ; 65 to 

Distilling at over 35O'F 
Heavy oils, paraffin wax, 
etc, 15 to 20% 

FIG. 94. Approximate fractions in the distillation of crude oil. 

Temperature in the 

Kind of oil after condensing the vapor 


100F to 125F. 

125F. to 350F. 
Over 350F. 

Highly volatile oils (gasoline, benzine and 
Kerosene and light lubricating oils. 
Heavy oils, paraffin wax and residue. 

10 to 15 per cent. 

65 to 75 per cent. 
15 to 20 per cent. 

It will be noticed that there is from three to five times as much kerosene 
and light lubricating oils produced under this method as there is gasoline. 
This accounts for the late scarcity of gasoline and the more volatile fuels, 
and the overproduction of kerosene and the less volatile fuels, which can 
not be used successfully in an automobile engine. 

In order to utilize a part of these less volatile fuels, the Standard Oil 
Co. has developed the Burton process by which these less volatile fuels 
are redistilled under pressure. This process gives an additional amount 
of volatile fuel very much like the gasoline obtained from the first distilla- 
tion. This process has increased the percentage of gasoline from the 
crude oil to such an extent that the market is now liberally supplied. 

The Bureau of Mines has recently developed the new Rittman process 
for increasing the amount of gasoline produced from the crude oil. It 
is a continuous process, in contrast to the "batch" Burton process. The 
two processes are somewhat similar in character and have as their end an 
increase in the production of gasoline from the crude oil. 

62. Principles of Vaporization. Before an explosive mixture can be 
formed, the liquid fuel must first be turned into a gas and then mixed 
with the proper amount of air to burn it. As we know, it requires heat to 


change water into steam or vapor. If the water is out in the open, it will 
evaporate rapidly, or boil, at a temperature of 212. Likewise, in order 
to change a liquid fuel into a gas or vapor, it is necessary that heat be 
added to it, but the temperature at which this heat is added is different for 
different fuels. For instance, gasoline will evaporate under the usual 
atmospheric pressure and temperature and will, in some cases, evaporate 
at a temperature close to F. This can be tested by exposing a pan 
of gasoline to the air. In a short time the liquid will have evaporated. 
That heat has been absorbed can be verified by feeling of the dish before 
it is filled and again after evaporation has been taking place. 

Kerosene and alcohol, on the other hand, will not evaporate until heat 
is added from an external source at a higher temperature, the same as is 
done when steam is made from water. This explains the difficulty of 
evaporating these fuels for use in a gas engine. 

From the above considerations, the general principles of vaporization 
are formulated : 

1. The heavier a liquid and the higher its boiling point, the harder 
it will vaporize; for example, kerosene as compared with gasoline. 

2. A liquid fuel will vaporize easier and faster under a suction, or re- 
duction of pressure than under pressure ; for example, gasoline is more dif- 
ficult to vaporize at low than at high altitudes. 

3. The closer the temperature of a liquid fuel is to its boiling point, 
the easier and faster it will vaporize; for example, gasoline will vaporize 
more readily in summer than in winter. 

The Baume Test. Gasoline is usually spoken of as high or low test. 
By reference to the principles of vaporization, we see that the heavier 
a liquid, the harder it is to evaporate. This principle explains the reason 
for the use of the Baume" test. A hydrometer, such as shown in Fig. 
95 is graduated in degrees, the numbers reading from the bottom up. 
These degrees have nothing to do with thermometer degrees, but are 
named after Baume, who originated the idea. When the hydrometer is 
placed in a quantity of gasoline, it will sink to a depth corresponding to 
the density of the liquid. It will sink deeper in a light gasoline than in a 
heavier one. The deeper the hydrometer sinks, the higher the scale read- 
ing will be. This scale, reading from 45 to 95 Baume", indicates in an 
indirect way the ease and rapidity with which the gasoline will evapo- 
rate. It is not a direct and absolute test unless the nature and the 
boiling points of the crude oil from which the gasoline has been distilled 
are known. For most purposes, however, it merely serves as a guide as to 
the way the gasoline will act in service. 

Gasoline. The commercial gasoline of today has a Baume" test of 
from 50 to 65, the better or high test being in the neighborhood of 65 
and the poorer, or low test, in the neighborhood of 50. For summer 



use, the low test or heavier gasoline can be used very .well because it 
will evaporate with comparative ease at the usual summer temperatures, 
but in the winter the high test or light gasoline is to be preferred because 
it will evaporate more easily at the low temperatures. More work can 
be obtained from a gallon of the heavier or low test gasoline, providing it is 
completely vaporized, but it is very difficult to vaporize at low tempera- 
tures and consequently makes starting very hard in cold weather. 

Kerosene Gasoline 

FIG. 95. Baum6 hydrometer in kerosene and gasoline. 

Occasionally, a low grade, impure gasoline is sold which lacks sufficient 
refinement and purification, the sulphur and other impurities not having 
been eliminated. The use of this may result in carbon deposits in the 
cylinders. A gasoline that readily carbonizes should be avoided and a 
higher grade used. 

Kerosene and Alcohol. To use either of these fuels requires the heating 
of the fuel or the air, or both, in order to secure vaporization. At pres- 
ent, the price of alcohol is too high to warrant giving any serious con- 
sideration to its use. Several more or less successful devices have been 
tried for using kerosene, but the varying speeds and loads of the auto- 


mobile engine make the problem of controlling the heat very difficult. 
The reductions in the price of gasoline in the past 2 or 3 years and the 
very promising prospects for a greater increase in the supply and corre- 
sponding reduction in the price, make it unlikely that any great develop- 
ment in the use of kerosene will take place. Consequently, the discussion 
to follow will deal only with gasoline and its vaporization. 

53. Heating Value of Fuels. The heating value, or the amount of 
heat energy contained in a liquid fuel, is given in British thermal units 
per pound; a British thermal unit, or a B.t.u., being the quantity of 
heat energy required to raise the temperature of 1 Ib. of water 1 on the 
Fahrenheit scale. The following table gives the heating values of the 
common fuels: 

Gasoline 18,000 to 19,500 B.t.u. per pound. 
Kerosene about 20,000 B.t.u. per pound, 
grain about 10,000 B.t.u. per pound. 

Alcohol ^ wQod about 7)5(X) B t u per pound 

Inasmuch as the heavier fuel contains more pounds per gallon, and as 
gasoline and kerosene are sold by the gallon, a gallon of heavy or low test 
gasoline or of kerosene contains more energy and gives more power than a 
gallon of light, or high test gasoline. 

54. Gasoline Gas and Air Mixtures. It is necessary when the gaso- 
line is vaporized that it be mixed with the proper amount of air to form 
an explosive mixture. If too little air is furnished, there will not be enough 
oxygen to burn the carbon and hydrogen in the fuel and the fuel will be 
wasted, as will be indicated by black smoke coming from the exhaust. 
If too much air is furnished, the mixture is weak in fuel, giving a very slow 
combustion. This results in lost power. A weak mixture, or an excess of 
air, is indicated by back-firing through the carburetor. 

A definite mixture of gasoline gas and air is necessary for the efficient 
operation of a gasoline engine. The function of the carburetor is to take 
the gasoline, vaporize it, and furnish the proper mixture of gas and air to 
the cylinders under all conditions of temperature, speed, load, power and 
varying atmospheric conditions. 

55. Principles of Carburetor Construction. Most of the modern 
types of carburetors are of the spray or nozzle type, in which a jet of gaso- 
line is sprayed into a current of air to form an explosive mixture. Figure 
96 illustrates an elementary spray carburetor. The gasoline supply tank 
is placed below the carburetor and the gasoline is pumped up through the 
supply pipe. The overflow pipe maintains the level of the liquid at a 
constant height. The standpipe T is connected with the supply chamber 
C by means of the connection N and the flow is regulated by the needle 
valve S. The gasoline level in the standpipe T is always the same. 
The flange B is fastened onto the intake passage of the engine. The sue- 



tion of the piston draws air through the opening A upward past the stand- 
pipe, and at the same time draws a spray of gasoline from T. The but- 
terfly valve D is for the purpose of regulating the suction upon the stand- 
pipe T when starting the engine; when running, the valve D should be 
wide open. The mixture is changed by regulating the needle valve 8. 
This type of carburetor can be used only on constant speed engines, the 
reason for which we will see later. Figure 97 shows another elementary 
type of carburetor which illustrates the application of two modern ideas. 
In this case, the gasoline supply is maintained at a constant level by 
means of a hollow metal or a cork float operating a ball valve. The 

Fro. 96. 

FIG. 97. 

arrangement requires the gasoline supply tank to be placed above the 
carburetor or that some other means be provided for supplying gasoline 
under pressure. It will also be noticed that the passage surrounding the 
standpipe or spray nozzle is contracted, giving the inside surface a convex 
shape. This is the application of the well known Venturi tube principle. 
By contracting the section near the opening of the nozzle the velocity of 
the incoming air and consequently the suction at that point are increased, 
making it much easier for the gasoline to be taken up and greatly facili- 
tating the starting of an engine when the suction is low. 

This type of carburetor could be used on constant speed engines only. 
If a carburetor such as shown in Figs. 96 or 97 was put on a variable speed 
engine and the proper adjustment made by means of the needle valve so 
that the mixture proportions were correct at low speed, and the engine 
should then be speeded up, we would discover black smoke coining from 
the exhaust, indicating an excess of gasoline over the air supplied. This is 
due to the fact that under the increased suction due to the higher speeds 
of the piston, the air drawn in past the standpipe expands and increases 
in volume and velocity faster than it increases in weight; while the gasoline 
drawn from the nozzle, being a liquid, increases in weight just as its 
velocity and volume are increased. This means that under an increased 
suction too much gasoline is supplied for the amount of air drawn in. 


In order to keep the mixture of the proper proportions at all speeds of the 
engine, it is necessary to have an auxiliary air entrance, such as indicated 
at X in Fig. 98, to admit an additional amount of air at the higher engine 
speeds. This entrance is usually in the form of a valve controlled by a 
spring, the tension on which can be changed to control the air admission. 
For low speed adjustments the gasoline needle valve is to be used, and for 
high speed adjustments the auxiliary air valve is to be adjusted. That is, 
when the engine is running comparatively slowly, the air is taken in 
through the ordinary air opening A shown below the valve in Fig. 98. 

FIG. 98. FIG. 99. 

FIGS. 98 AND 99. Sections of typical variable speed carburetors. 

The mixture is then proportioned by means of the needle valve NV. 
When the engine speeds up, and the suction is increased, the auxiliary air 
valve S in Fig. 98 comes into action and opens. If it is found that the 
mixture at high speeds is too rich, that is if there is too much fuel for the 
air furnished, it indicates that the tension on the valve spring is too great, 
which prevents sufficient air from entering. By reducing the tension, the 
valve opens wider, letting in sufficient air to keep the mixture uniform. 
If the mixture is too weak at high speeds, the spring tension is too weak. 
It should be tightened so as to permit less air to enter and to increase the 
suction on the gasoline. 

The following general description applies to Fig. 98. 

G = gasoline feed from tank. 
FV = float valve controlling flow of gasoline to carburetor. 

F = float, the height of which is regulated by the level of gasoline in the float 

chamber. The float controls the float valve FV. 

NV = gasoline needle valve for regulating the amount of gasoline furnished to the 
air in the mixing chamber. 

N = gasoline nozzle. 

X = auxiliary air valve, to admit additional air at the high speeds. 

S = spring for X. 

A = primary air opening, which supplies all air at low speeds. 

T = throttle valve for regulating supply of mixture from carburetor to cylinder. 

P = primer for depressing float and flooding carburetor to insure rich mixture 
when starting. 



Figure 99 shows another carburetor, in which the auxiliary air is ad- 
mitted through ports X controlled by steel balls B. 

Some of the modern types of carburetors are water-jacketed, taking 
the hot water from the cooling system, in order to heat the carburetor 
and assist the vaporization. Another method of assisting the vapori- 
zation, and one almost necessary when the low grade gasoline of today 
is considered, is that of heating the air which goes into the carburetor. 
This is usually done by taking it through a jacket surrounding the ex- 
haust pipe. Figure 100 shows such a device. 

FIG. 100. Hot-air connection used with Master carburetor. 

Another scheme used in several of the carburetors built for high 
powered, high speed machines is the double-jet, which makes it easier 
for the engine to draw the desired amounts of gasoline and air when it 
becomes necessary for the engine to carry heavy loads at high speed. 
Several of these are illustrated in the following articles, which describe 
some of the leading carburetors now in use. 

FIG. 101. Schebler Model L carburetor. 

56. Schebler Model L Carburetor. The Model L carburetor, Figs. 
101 and 102, is of the lift-needle type and is so designed that the amount 
of fuel entering the motor is controlled by means of a raised needle work- 
ing automatically with the throttle. The flow of gasoline can be adjusted 



for closed, intermediate, or open throttle positions, each adjustment being 
independent and not affecting either of the others. This carburetor 
has an automatic air valve, shown at the left in Fig. 102. At high speeds 
or heavy loads, the suction raises this valve and admits an extra supply of 
air. The opening of the throttle for high speed or a heavy pull raises 
the needle and increases the supply of gasoline to correspond with the 
increased air supply. 

The Model L can be furnished with a bend for connecting or taking 
warm air from around the exhaust manifold into the initial air opening at 
the base of the carburetor, by means of a hot air drum and tubing. 

FIG. 102. Section of Shebler Model L carburetor. 

This carburetor is also manufactured with a dash-control to the air 
valve spring, this being operated by a lever which is controlled by a 
switch on the dashboard or steering post of the car. This control is 
shown on Fig. 102. 

Rules for Adjusting Schebler Model L. The carburetor should be 
connected to the intake manifold so that it is located below the bottom of 
the gasoline tank a sufficient distance to be filled by gravity under all 
running conditions. Where pressure feed is used, it is unnecessary to 
locate the carburetor below the gasoline tank; also, when pressure is used, 
it is never advisable to carry over 2 Ib. 

Before adjusting the carburetor, make sure that the ignition is prop- 
erly timed; that there is a good hot spark at each plug; that the valves are 
properly timed and seated; that all connections between the intake valves 
and the carburetor are tight; and that there are no air leaks of any kind 


in these connections. The carburetor should be adjusted to the motor 
under normal running temperature, and not to a cold motor. 

In adjusting the carburetor, first make the adjustments on the auxili- 
ary air valve so that the air valve seats lightly but firmly. The lever on 
the dash control should be set in the center of the dashboard adjuster, 
and with this setting of the lever, the tension on the air valve should be 
light, yet firm. Close the needle valve by turning the adjustment screw 
to the right. until it stops. Do not use any pressure on this adjustment 
screw after it meets with resistance. Then turn it to the left about four 
or five turns and prime or flush the carburetor by pulling up the priming 
lever and holding it up for about 5 seconds; Next, open the throttle 
about one-third and start the motor; then close the throttle slightly, 
retard the spark, and adjust the throttle lever screw and the needle 
valve adjusting screw, so that the motor runs at the desired speed and 
hits on all cylinders. 

After getting a good adjustment with the motor running idle do not 
touch the needle valve adjustment again, but make your intermediate 
and high speed adjustments on the dials. Adjust the pointer on the first 
dial about half way between figure 1 and figure 3. Advance the spark 
and open the throttle so that the roller on the track running below the 
dials is in line with the first dial. If the motor back-fires with the throttle 
in this position and the spark advanced, turn the indicator a little more 
toward figure 3; if the mixture is too rich, turn the indicator back, or 
toward figure 1, until you are satisfied that the motor is running properly 
with the throttle in this position, or at intermediate speed. Now open the 
throttle wide and make the adjustment on the second dial for high speed 
in the same manner as you have made the adjustments for intermediate 
speed on the first dial. 

67. Schebler Model R. The Model R Schebler carburetor, Fig. 103, 
is designed for use on both four- and six-cylinder motors. It is a single-jet 
raised-needle type of carburetor, automatic in action. The air valve 
controls the lift of the needle so as to automatically proportion the amount 
of gasoline and air at all speeds. 

The Model R carburetor is designed with an adjustment for low speed. 
As the speed of the motor increases, the air valve opens, raising the gaso- 
line needle and thus automatically increasing the amount of fuel. This 
carburetor has but two adjustments, the low speed needle adjustment, 
which is made by turning the air valve cap, and an adjustment on the air 
valve spring for changing its tension. 

The Model R carburetor has an eccentric which acts on the needle 
valve, intended to be. operated either from the steering column or from the 
dash, and insures easy starting, as, by raising the needle from the seat, 
an extremely rich mixture is furnished for starting and for heating up the 



motor in cold weather. A choke valve in the air bend is also furnished. 
The dashboard control or steering column control must be used with this 
carburetor; it cannot be operated satisfactorily without them. 

Rules for Adjusting Model R Carburetor. When the carburetor is 
installed, see that lever B is attached to the steering column control or 
dash control so that when boss D of lever B is against stop C the lever on 
the steering column control or dash control will register "Lean" or "Air." 
This is the proper running position for lever B. 

FIG. 103. Schebler Model R carburetor. 

To adjust the carburetor turn the air valve cap A clockwise or to the 
right until it stops, then turn it to the left or anti-clockwise one complete 

To start the engine, open the throttle about one-eighth or one-quarter 
way. When the engine is started, let it run till it is warmed, then turn the 
air valve cap A to the left or anti-clockwise until the engine hits perfectly. 
Advance the spark three-quarters of the way on the quadrant; then if the 
engine back-fires on quick acceleration, turn the adjusting screw F up 
(which increases the tension on the air valve spring) until acceleration is 

Turning the air valve cap A to the right or clockwise lifts the needle E 
out of the nozzle and enriches the mixture; turning to the left or anti- 
clockwise lowers the needle into the nozzle and makes the mixture lean. 


When the motor is cold or the car has been standing, move the steer- 
ing column or dash control lever toward "Gas" or "Rich." This oper- 
ates the lever B and lifts the needle E out of the gasoline nozzle and makes 
a rich mixture for starting. As the motor warms up, move the control 
lever gradually back toward "Air" or "Lean" to obtain best running 
conditions, until the motor has reached normal temperature. When 
this temperature is reached, the control lever should be at " Air " or "Lean." 
For best economy, the slow speed adjustment should be made as lean as 

68. The Holley Model H Carburetor. This carburetor is shown 
in Fig. 104. Before the fuel enters the float chamber, it passes a strainer 

FIG. 104. Holley Model H carburetor. 

disc A which removes all foreign matter that might interfere with the 
seating of the float valve B under the action of the cork float, and its 
lever C. 

Fuel passes from the float chamber D into the nozzle well E through a 
passage F drilled through the wall separating them. From the nozzle 
well, the fuel enters the cup G through the hole H, and rises past the needle 
valve, /, to a level which partially submerges the lower end of a small 
tube, J, having its outlet K at the edge of the throttle disc. 


Cranking the engine, with the throttle kept nearly closed, causes a 
very energetic flow of air through the tube J and its calibrated throttling 
plug K. But with the engine at rest the lower end of this tube is partially 
submerged in fuel. Therefore, the act of cranking automatically primes 
the motor. With the motor turning over under its own power, flow 
through the tube J takes place at very high velocity, thus causing the fuel 
entering the tube with the air to be thoroughly atomized upon its exit 
from the small opening at the throttle edge. This tube is called the 
"low speed tube" because, for starting and idle running, all of the fuel 
and most of the air in the working mixture are taken through it. 

As the throttle opening is increased beyond that needed for idling of 
the motor, a considerable volume of air is drawn down around the outside 
of the strangling tube L and then upward through this tube. In its pas- 
sage into the strangling tube, the air is made to assume an annular, con- 
verging stream form, so that the point in its flow at which it attains its 
highest velocity is in the immediate neighborhood of the upper end of 
the ' ' standpipe " M . The velocity of air flow being highest at the upper or 
outlet end of the standpipe, the pressure in the air stream is lowest at the 
same point. For this reason, there is a pressure difference between the 
top and bottom openings of the pipe M , thus causing air to flow through 
it from bottom to top, the air passing downward through the openings 
N in the bridge supporting the standpipe and then up through the 

With a very small throttle opening, the action through the standpipe 
keeps the nozzle cup thoroughly cleaned out, the fuel being carried directly 
from the needle opening into the entrance of the standpipe. . To secure 
the best vaporization of the fuel, the passage through the standpipe is 
given an aspirator form, which further increases the velocity of flow 
through it, and insures the greatest possible mixing of the fuel with the 
air. A further point is that the vaporized discharge of the standpipe 
enters the main air stream at the point at which the latter attains its 
highest velocity and lowest pressure. 

There is but one adjustment, that of the needle valve /. The effect 
of a change in its setting is manifest over the whole range of the motor. 

59. Holley Model G. This carburetor, Fig. 105, is a special design 
for Ford cars. 

The operation of this carburetor is the same as the regular Model H 
already illustrated and described. The chief differences are the structural 
ones giving a horizontal instead of a vertical outlet, a needle valve con- 
trolled from above instead of from below, and a simplification of design to 
secure compactness. 

Fuet enters the carburetor by way of a float mechanism in which a 
hinged ring float, in rising with the fuel, raises the float valve into contact 


with its seat. This seat is removable and the float valve is provided with 
a tip of hard material. 

From the float chamber the gasoline passes through the ports E to 
the nozzle orifice, in which is located the pointed end of the needle F. 
The ports E are well above the bottom of the float chamber, so that, even 
should water or other foreign matter enter the float chamber, it would 
have to be present in very considerable quantity before it could interfere 
with the operation of the carburetor. A drain valve D is provided for 
the purpose of drawing off whatever sediment or water may accumulate 
in the float chamber. 

FIG. 105. Holley Model G carburetor. 

The float level is so set that the gasoline rises past the needle valve F 
and sufficiently fills the cup G to submerge the lower end of the small tube 
H. Drilled passages in the casting communicate the upper end of this 
tube with an outlet at the edge of the throttle disc. The tube and passage 
give the starting and idling actions, as described in connection with the 
Holley Model H. 

The strangling tube / gives the entering air stream an annular con- 
verging form, in which the lowest pressure and highest velocity occur 
immediately above the cup G; thus it is seen that the fuel issuing past the 
needle valve F is immediately picked up by the main air stream, at the 
point of the latter's highest velocity. 

The lever L operates the throttle in the mixture outlet. A larger disc 
with its lever S forms a spring-returned choke valve in the air intake, for 
starting in extremely cold weather. 



60. Stewart Model 25. This carburetor, which is manufactured by 
the Detroit Lubricator Company, involves an interesting principle of 

Figure 106 gives a cross section of this carburetor and shows the posi- 
tion of the air valve with engine running and air and gasoline being 

With the engine at rest and no air passing through the carburetor, the 
air valve A rests on the seat B, closing the main air passage. The gasoline 
rises to a height of about 1^ in. below the top of the central aspirating 

FIG. 106. Stewart Model 25 carburetor. 

tube L. As soon as the engine starts to rotate, a partial vacuum is formed 
above the air valve, causing it to lift from its seat and admit air, at the 
same time gasoline being drawn up through the aspirating tube L. The 
lower end of the air valve extends down into the gasoline and around the 
metering pin P. Due to the decreasing diameter of this pin, the higher 
the air valve is lifted the larger will be the opening into the tube L, and 
the more gasoline will be drawn up. The upper end of the air valve meas- 
ures the air, the lower end measures the gasoline; therefore, as the suction 
varies, the air valve moves up or down and the volume of air and the 
amount of gasoline admitted to the mixing chamber increase or decrease 
in the same ratio. Most of the air passing through the carburetor goes 
through the air passages as indicated by the black arrows. A -small 
amount is drawn through the drilled holes HH and past the end of the 



tube L. The flared end of this tube deflects the air through a small an- 
nulus, thereby increasing the velocity of air at this point so as to aid in 
atomizing the fuel. 

The air valve is restrained from any tendency to flutter, caused by the 
intermittent suction of the cylinders, by the dash pot D. Due to the 
greater inertia of the gasoline and because it flows comparatively slowly 
through the small opening and into the dash pot, the air valve can rise or 
fall only as liquid is expelled or admitted and thus the air valve is held 
steady. The Stewart carburetors have but one adjustment, which raises 
or lowers the metering pin, thereby decreasing or increasing the amount of 
gasoline admitted to the mixing chamber. The correct position of the 
metering pin is determined with the motor running at idling speed. This 
adjustment may be manipulated at the dash to compensate for extreme 
changes in atmospheric temperatures and for use in starting in cold 

61. Kingston Model L. Figure 107 shows the construction of this car- 
buretor. Gasoline enters the carburetor from the tank at the connection 
A and is maintained at a constant level, through the agency of the float. 

A pool of gasoline forms in the base of 
the U-shaped mixing tube and will always 
be present when the motor is not run- 
ning. This aids in positive starting. 
When the motor starts, this pool is 
quickly lowered to the point of adjust- 
ment of the needle valve and continues 
to feed from this point till the motor is 

When the motor is running slowly, 
the air valve B rests lightly on its seat, 
allowing no air to pass through; con- 
sequently all air must pass through the 
low speed mixing tube C. Due to the lower end of this tube being close 
to the spray nozzle and all the low speed air having to pass this point, 
the atomized gasoline drawn from nozzle D becomes thoroughly mixed 
with air in its upward course and is carried in this state to the motor. 
When the throttle is opened slowly, the following action takes place. 
The motor now requires a greater volume of mixture. The air valve B 
slowly leaves its seat, permitting an extra air supply to enter and compen- 
sate for the increased flow of gasoline produced by the greater suction of 
the motor. In this carburetor the extra amount of gasoline for the 
starting and warming up period can be obtained by opening the needle 
valve .adjustment at the dash or by the use of the choke throttle E placed 
in the air passage, 

FIG. 107. Kingston Model L 


When starting with a cold motor, this choke throttle can be closed by 
pulling the wire forward. This cuts off nearly all the air supply and pro- 
duces a very strong suction at the spray nozzle, which causes the gasoline 
to jet up and be carried with the incoming rush of air to the cylinders. 

A drain cock G is placed at the lowest point in the bowl and should be 
opened from time to time to free the bowl of all water and foreign matter. 

Rules for A djusting Kingston Model L. Retard the spark fully. Open 
the throttle about five or six notches of the quadrant on the steering post. 
Loosen the needle valve binder nut on the carburetor until the needle valve 
turns easily.. Turn the needle valve (with dash adjustment) until it 
seats lightly. Do not force it. Adjust it away from its seat one com- 
plete turn. This will be slightly more than necessary but will assist in 
easy starting. 

Start the motor and open or close the throttle until the motor runs at 
fair speed, not too fast, and allow it to run long enough to warm up to 
service conditions. Now make the final adjustment. This carburetor 
has but one adjustment the needle valve. Close the throttle until the 
motor runs at the desired idling speed. This can be controlled by ad- 
justing the stop screw in the throttle lever. 

Adjust the needle valve toward its seat slowly until the motor begins 
to lose speed, thus indicating a weak or lean mixture. Now adjust the 
needle valve away from its seat very slowly until the motor attains its 
best and most positive speed. This should complete the adjustment. 
Close the throttle until the motor runs slowly, then open it rapidly. The 
motor should respond strongly. Should the acceleration seem slightly 
weak or sluggish, a slight adjustment of the needle valve may be advisable 
to correct this condition. With the adjustment completed, tighten the 
binder nut until the needle valve turns hard. 

62. Marvel Carburetor. The Marvel, shown in Fig. 108, is of the 
double nozzle type, the second nozzle coming into action at high speeds. 
At low speeds all the air is drawn through the venturi tube, where it takes 
up gasoline from the primary nozzle. At high speeds after the air has 
passed the choke damper, it divides, part of it going through the venturi 
tube around the low speed spray nozzle, and the remainder passing to one 
side and opening the auxiliary valve against the pressure of its spring. 
Near the top of the auxiliary air valve is the secondary or high speed 
spray nozzle. 

The rush of air through the venturi tube picks up and vaporizes the 
gasoline from the low speed nozzle and carries it in suspension past the 
throttle and to the cylinders. When the suction at the auxiliary air valve 
has increased sufficiently to open this valve and create a high velocity at 
this point, gasoline is also picked up from the high speed nozzle and car- 
ried to the cylinders in like manner, 



The choke damper in the air inlet is used only for starting the motor, 
by partially shutting off the air supply and forcing the motor to suck in a 
rich mixture. 

To the throttle is connected a hot air damper, which when open al- 
lows the exhaust gas from the motor to flow through a cored passage 
around the throttle, where it heats the mixture of gasoline and air. A 
tube connects this passage with another which surrounds the venturi tube 
and spray nozzle, and provides heat for the incoming fuel and air. 

Hot air jacket 

xing chamber ^ 



/ . Hot air damper 

Auxiliary air valve 
Auxiliary spray nozzle 

~Neea'/e valve 

FIG. 108. The Marvel carburetor. 

Rules for Adjusting the Marvel Carburetor. The following rules for 
adjustment are given by the manufacturers: 

Start by turning the needle valve A to the right until it is completely 
closed, and the air adjustment B to the left until it stops. Now give the 
air adjusting screw B three complete turns to the right, and open the 
needle valve A two complete turns to the left. Start the motor as usual, 
using the strangler button to get a rich mixture at first. Close the 
throttle until the motor runs slowly and verify the needle valve adjust- 
ment A by turning it to the right a little at a time (% to % of a turn should 
be sufficient) until the motor runs smoothly and evenly. At this point the 
motor should be allowed to run until thoroughly warmed up. 

After the motor has warmed up, turn the air valve adjusting screw B 
to the left, a little at a time, until the motor begins to slow down. This 
indicates that the air valve spring is too loose. Turn it back to the right 
just enough to make the motor run well. 

To test the adjustment, advance the spark and open the throttle 
quickly. The motor should "take hold" instantly and speed up at once. 



If it misses or pops back in the carburetor, open needle valve A slightly by 
turning to the left. Do not move the air adjusting screw B any more un- 
less it appears absolutely necessary. 

The best possible adjustment has been secured when the air adjust- 
ment B is turned as far as possible to the left and the needle valve A is 
turned as far as possible to the right, providing the motor runs smoothly 
and picks up quickly when the throttle is opened. 




FIG. 109. Stromberg Model H carburetor. 

If the motor runs too fast with throttle closed, turn the small set screw 
in throttle stop to the left. If the motor stops when the throttle is fully 
closed, turn the set screw to the right. 

As the throttle opens, the hot air damper, which is connected to it by a 
link, gradually closes, the greatest amount of hot air passing through the 
jackets when the throttle is nearly closed. The position of the hot air 
damper at any time is indicated by the slot at the end of the damper 
shaft. By loosening the set screw in the damper lever, this can be set 


for any desired relation between the damper and the throttle. Ordinarily 
the hot air damper should be nearly horizontal when the throttle is closed. 

63. Stromberg Model H. The Stromberg Model H carburetor, 
shown in Fig. 109, is of the double-jet type with two adjustments, for 
high and low speed, both working on the gasoline supply. 

The gasoline in the glass float chamber is regulated by the hollow metal 
float. The fuel for low speed is furnished by the spray nozzle in the ven- 
turi tube, through which the low speed air passes. The adjustment for 
this nozzle is by means of the needle valve, as shown. 

At high speed, the auxiliary air comes through the auxiliary air valve, 
which in turn automatically regulates the gasoline flow from the auxiliary 
gasoline valve. This supplies the extra gasoline for high speed and heavy 
duty service. 

The dash pot with the piston riding in gasoline prevents all fluttering 
of the air valve on its seat when opening and closing. 

This type of carburetor is fitted with a strangling or choke valve in 
the primary air inlet, for starting in cold weather. This assists in the 
vaporization of the gasoline by increasing the suction on the liquid. 

The spring tension on the air valve and auxiliary needle valve is con- 
trolled either from the dash or from the steering post, depending upon the 
style of control installed. This permits adjustments to be made in order 
to compensate for varying conditions of weather, fuel, and operation. 

64. Zenith Model L. This carburetor, shown in Fig. 110, differs from 
most conventional types in the absence of auxiliary air valves. It is a 
"fixed" adjustment carburetor, and has as its particular feature the 
"compound nozzle." The compound nozzle consists of an inner nozzle, 
the gasoline for which is furnished direct from the float chamber. The 
amount of gasoline leaving this nozzle varies with the suction and conse- 
quently the mixture from this nozzle would be too rich at high speeds. 
To compensate for this rich mixture, the compensating nozzle surround- 
ing the main nozzle furnishes a mixture "too weak " at high speeds. This 
is because the gasoline feed to this jet is constructed so as to be constant 
at all speeds. When the engine speeds up, the amount of air increases 
and the compensating mixture is a weak one. This answers the purpose 
of the auxiliary air valve on other types of carburetors and keeps the 
mixture of constant proportions. By a proper selection of the two nozzles 
a well balanced mixture can be secured through the entire range. 

In addition to the compound nozzle, the Zenith is equipped with a 
starting and idling well. This well terminates in a priming hole at the 
edge of the butterfly valve, where the suction is greatest when the valve 
is slightly open. The gasoline is drawn up by the suction at the priming 
hole and, mixed with the air rushing by the butterfly, gives a rich slow 
speed mixture. The slow speed mixture is regulated by the regulating 



screw, which admits air to the priming well. At higher speeds with the 
butterfly valve opened, the priming well ceases to operate and the com- 
pound nozzle drains the well and compensates for any engine speed. 

Fia. 110. Zenith Model L carburetor. 

65. Rayfield Model G. This carburetor is illustrated in Figs. Ill and 
112. It has two jets and the gasoline is drawn through them into 
the mixing chamber, the quantity being controlled by adjustments on the 
outside of the carburetor. As will be noticed, there are no air valve ad- 
justments, but two gasoline adjustments, a low speed adjustment and a 
high speed adjustment. The names of the lettered parts on Fig. Ill are 
as follows: 

D Throttle Arm. 
G Priming Lever. 
H Gas Arm. 

M Regulating Cam. 
S Drain Cock. 
U Needle Valve Arm. 
X Drain Cocks. 

The suction created by the downward motion of the motor pistons 
draws air into the mixing chamber through the primary and auxiliary 
air inlets. This air rushes through the mixing chamber, around the nozzle 



and the metering pin, and picks up the gasoline which leaves the nozzle 
and jet in the form of a spray. Thus the action of the mixing chamber is 
not unlike that of an ordinary atomizer in which the air, forced from the 
rubber bulb, picks up a certain amount of the liquid in the bottle and 
sprays it out in the form of a fine vapor. 

That the proportion of air and gasoline in the mixture may be correct 
for all motor speeds, one fixed air inlet and two variable auxiliary air 
inlets are provided. The lower air valve opens and closes with the main 
or upper automatic air valve, giving a greater volume of air in proportion 
to the greater amount of gasoline to be vaporized. In other words, at 
high motor speeds or when the throttle is fully opened, the motor requires 
more gas and consequently a greater volume of air to vaporize the gasoline 


FIG. 111. Rayfield Model G carburetor. 

which comes through the spray nozzles; at low mo tor speeds, less gas is 
required and consequently less air is necessary to vaporize the gasoline. 

At the front end of the carburetor is the main auxiliary air valve. 
This is controlled by a spring and dashpot. At low speeds, when only a 
small amount of air is being drawn through the carburetor, the spring and 
dashpot hold this valve almost shut. As the speed increases and more 
air is needed, the suction operating against the tension of the spring draws 
the valve further and further open, thus giving an increased supply of 
air in proportion to the need for the increased speed. The motion of this 
valve moves the metering pin and admits an additional supply of gasoline 
at this second nozzle. 

Rules for Adjusting Rayfield Model G. With throttle closed, and dash 
control down, close the nozzle needle by turning the low speed adjustment 



to the left until block U slightly leaves contact with the cam M . Then 
turn to the right about three complete turns. Open the throttle not more 
than one-quarter. Prime the carburetor by pulling steadily a few seconds 
on the priming lever G. Start the motor and allow it to run until warmed 
up. Then with retarded spark, close the throttle until the motor runs 
slowly without stopping. Now, with the motor thoroughly warm, make 
the final low speed adjustment by turning the low speed screw to the left 
until the motor slows down and then turn to the right a notch at a time 
until the motor idles smoothly. 

To make the high speed adjustment, advance the spark about one- 
quarter. Open the throttle rather quickly. Should the motor back-fire, 
it indicates a lean mixture. Correct this by turning the high speed ad- 
justing screw to the right about one notch at a time, until the throttle 
can be opened quickly without back-firing. 

FIG. 112. Section of Rayfield Model G carburetor. 

If "loading" (choking) is experienced when running under heavy 
load with throttle wide open, it indicates too rich a mixture. This can be 
overcome by turning the high speed adjustment to the left. 

66. Carter Model C. The Carter carburetor, shown in section in 
Fig. 113, is of unconventional design and construction in many ways. 
The float is of copper and is spherical in shape. The float valve is pro- 
vided with a shock absorber to prevent the valve from pounding on its 
seat when the car is being driven over rough roads. 

There are three adjustments, for low, intermediate, and high speeds. 
The adjustable fuel tube gives the advantages of multiple jets. For low 
speeds the air taken in just above the bottom of the fuel tube takes 
gasoline from around the bottom of the tube. Under increased suction 
the gasoline is sucked higher in the tube and is sprayed through a number 
of openings in the side of the fuel tube into the air coming through the 


intermediate air valve. The high speed air adjustment is made from a 
lever connection on the dash. 

67. General Rules for Carburetor Adjustment. Very few general 
rules can be given for the adjustment of a carburetor. It is usually a 
very wise plan to let well enough alone, but if adjustments are necessary, 
it is very essential that they be made by someone familiar with the carbu- 

FIG. 113. Carter Model C carburetor. 

retor, or that the manufacturers' instructions be followed out in detail. 
The common carburetor troubles and remedies will be taken up in 
Chap. IX. 

On most types of carburetors, there are two adjustments to be made, 
a low speed adjustment and a high speed adjustment. The low speed 
adjustment is made with the engine running idle, the spark retarded, and 
the throttle about one-quarter open. This is usually the gasoline adjust- 
ment. The high speed, or auxiliary air adjustment, is made with the en- 
gine running with throttle open and spark advanced. In all cases the 
adjustment should be made after the engine has warmed up to its normal 
running temperature. 

Judging the mixture is largely a matter of experience. A rich mixture 
is indicated by the overheating of the cylinders, waste of fuel, choking 
of the engine and mis-firing at low speeds, and by a heavy black exhaust 
smoke with a very disagreeable odor. A weak mixture manifests itself 
by back-firing through the carburetor and by loss of power. A proper 
mixture will give little or no smoke at the exhaust. Blue smoke is caused 
by the burning of excess lubricating oil and has no relation to the quality 
of the mixture. 



68. Carburetor Control Methods. The carburetor is controlled from 
the driver's seat. The hand throttle on the steering post regulates 
the amount of mixture to the cylinders, thus regulating the engine and 
car speed. In conjunction with the throttle connection, is the ac- 
celerator on the toe-board, which permits the throttle to be opened by 
the foot, independently of the hand lever. The accelerator must be 
held open by the pressure of the foot. As soon as pressure is removed 
from it, the throttle closes to the point set by the hand lever. The air 
and gasoline adjustments are usually made from the dash of the car. 

69. The Gravity Feed System. There are numerous systems for 
feeding the gasoline to the carburetor from the gasoline tank, which 
may be placed at tho rear of the frame, in the cowl, or under the seat. 
These feed systems are classified as gravity, pressure, and vacuum systems. 

FIG. 114. Studebaker gravity feed system. 

In the gravity system of gasoline feed, the fuel flows to the carburetor 
by gravity alone. The tank may be placed either under the seat or in the 
cowl. If under the seat, there is the disadvantage of having to remove 
the cushions before being able to fill the tank. There is also the possi- 
bility in some cases that the tank will become lower than the carburetor 
when going up hill, and consequently the gasoline will not flow. Both 
of these disadvantages are done away with by placing the tank in the 
cowl. In either case, however, the pressure on the carburetor float valve 
varies as the level in the tank varies. When filling the tank, any gaso- 
line which spills or leaks either falls around the seat, in the car, or on the 
engine. The advantage of the gravity system is that it is simple and 
always ready. Figure 114 shows the gravity system used on the Stude- 


baker car, with the tank in the cowl. This shows the float operating the 
gasoline indicator. 

70. The Pressure Feed System. When the gasoline tank is placed at 
the rear of the frame, it is obviously impossible to use the gravity system. 
By putting a pressure in the gasoline tank, the gasoline may be forced by 
pressure to the carburetor. The pressure is maintained by a small air 
pump operated by the engine, or by a hand pump, or both. After filling 
the tank, a hand pump is used to get up pressure until the engine has 
been started. A safety valve in the pressure system keeps the pressure 
from getting too high. A particular advantage of this type of feed 


Shut.0 Golta. 

tor Check' 

FIG. 115. Pressure feed system. 

system is that gasoline feeds to the carburetor regardless of the position 
of the car. As in the gravity system, the pressure on the float valve is 
liable to vary. The filler cap is placed away from the engine and pas- 
sengers, and gasoline may be put in without disturbance. A typical 
pressure feed system is illustrated in Fig. 115. 

71. The Vacuum Feed System. Several systems have been developed 
in which the gasoline is transferred from the main tank at the rear of the 
car by vacuum, or suction, to a small auxiliary tank near the engine. 
From this small tank it flows by gravity to the carburetor. Figures 116 
and 117 show the installation of the Stewart vacuum system in a car, and 
Fig. 118 indicates the construction of the auxiliary vacuum tank. 

This system comprises a small round tank, mounted on the engine 
side of dash. This tank is divided into two chambers, upper and lower. 
The upper chamber is connected to the intake manifold, while another 
pipe connects it with the main gasoline tank. The lower chamber is 
connected with the carburetor. 



The intake strokes of the motor create a vacuum in the upper cham- 
ber of the tank, and this vacuum draws gasoline from the supply tank. 
As the gasoline flows into this upper chamber, it raises a float valve. 
When this float valve reaches a certain height, it automatically shuts 
off the vacuum valve and opens an atmospheric valve, which lets the 
gasoline flow down into the lower chamber. The float in the upper 

FIG. 116. The Stewart vacuum feed system. 

chamber drops as the gasoline flows out, and when it reaches a certain 
point it in turn reopens the vacuum valve, and the process of refilling 
the upper chamber begins again. The same processes are repeated 
continuously and automatically. The lower chamber is always open 
to the atmosphere, so that the gasoline always flows to the carburetor 
as required and with an even pressure. 

FIG. 117. Under the hood. The Stewart vacuum feed system. 

The amount of gasoline always remaining in the tank gets some heat 
from the motor and thereby aids carburetion; it also makes starting 
easier, by reason of supplying warm gasoline to the carburetor. The 
lower chamber of the tank is constructed as a filter, and prevents any 
water or sediment that may be in the gasoline from passing into the 
carburetor. A petcock, in the bottom of the tank, permits drawing off 



this sediment and also allows the drawing of gasoline, if required for 

priming or cleaning purposes. 

72. Intake Manifolds. The tendency in present engine design is 

to make the intake manifold of such shape and proportions that the 
path from the carburetor to the engine cylin- 
ders shall be as short and smooth as possible. 
Being close to the cylinders, the manifold as 
well as the carburetor is heated, greatly aiding 
the vaporization of the gasoline. The short 
manifold gives the gas very little chance to 
condense between the carburetor and the 
cylinders. It is also desirable to have the 
distance from the carburetor to the different 
cylinders the same in all cases. This insures 
the same amount of mixture to each cylinder. 
73. Care of Gasoline. Gasoline, being a 
volatile liquid, is very dangerous if not 
properly handled, but if proper care and at- 
tention are given to it there should be no 
danger whatever. It should never be ex- 
posed in a closed room, as it will evaporate, 
mix with the air, and form a very explosive 
mixture. Open lights should always be kept 
away from gasoline in all cases. When it is 
necessary to handle gasoline at night, it 
should be done with an electric light. Do 
not under any conditions use an open light. 

In putting out a gasoline fire, water will 
only spread the fire, as the gasoline, being 
FIG. 118. Stewart vacuum lighter than water, floats on it. The only 
successful method of extinguishing a gasoline 

fire is to smother it, either by sand, or a blanket, or by the gases from a 

fire extinguisher. 

The exhaust gases from a gasoline engine are very deadly. Do not 

breathe them for any length of time. If it becomes necessary to run 

your engine in a small garage with the doors closed, arrangement should 

be made to pipe the exhaust to the outside air. 


74. Friction and Lubricants. The purpose of lubrication is to reduce 
friction between moving surfaces. If parts moving on each other were 
not separated by a film of lubricant, the surfaces would rapidly rub 
away. Friction is a force that tends to retard the motion of one surface 
over another. The frictional force depends on the nature of the surface, 
and also on the kind of material. It is caused by the small projecting 
particles which extend from the surface. The rougher the surface and 
the softer the material, the greater the friction; or, the harder the material 
and the smoother the surface, the less the friction. The more friction 
there is, the greater the loss of power, as it requires power to overcome 
friction. A great amount of friction is necessary in certain parts of the 
car in order that they be efficient, such as in the brakes, the clutch, and 
the outer surface of the tires. On the other hand, it is essential that all 
friction possible be eliminated from the bearings in order to have as little 
of the motive power lost as possible. 

The principal lubricants used are fluid oils, semi-solids, and sometimes 
solids, such as graphite. There are three general sources of lubricants: 
animal oils, such as lard, fish oil, etc.; vegetable oil, such as olive oil, 
linseed oil, etc.; and mineral oils, which are secured from petroleum. 
These lubricating mediums should each be used where they are best 
adapted. An oil that is suitable for one part of the mechanism may not 
be suited for another part. Only mineral oils should be used in gasoline 
engine cylinders, as they alone meet the requirements. For this reason 
the oils used for steam engine cylinders are not good for gasoline engine 
use, as they do not withstand the high temperature which rises in the gas 
engine cylinder. There are two main requirements for good cylinder 
oil. It should have a high flash point, that is, it should not break down 
and give off inflammable gases at low temperatures; and, second, it 
should retain its body and not become so thin as to be worthless as a 
lubricant at high temperatures. It should have sufficient body to 
maintain a positive film between piston and cylinder, yet should not be 
so heavy as to retard the free motion of the piston and rings. It should 
also be free from acids or any form of vegetable or animal matter. The 
vegetable or animal matter will decompose at high temperatures and 
gum up the cylinder. The acid will etch the smooth surface of the 



cylinder and cause excess friction. A simple method to test for acid is 
to dissolve a little of the oil in warm alcohol and then dip a piece of blue 
litmus paper in the solution. If there is any acid present, the paper will 
turn red. The litmus paper can be obtained at any drug store. 

76. Cylinder Oils. Cylinder oils are usually classified in three 
grades; light, medium, and heavy. Light cylinder oil looks something 
like the ordinary machine oil, and is slightly more viscous. The medium 
is somewhat heavier than the light, and might be compared to warm 
maple syrup. Light and medium oils should be used only on engines 
which have close-fitting pistons. The heavy oil is used in air-cooled 
engines and in engines that have loose pistons or that become too hot 
to use the lighter grade of oil. A good gas engine oil should have a 
high degree of viscosity at 100F., a flash point not under 400, and a fire 
test of over 500. 

76. Viscosity. Viscosity is the property of a liquid by which it has a 
tendency to resist flowing. Oils are tested for viscosity by being put in a 
container and allowed to flow through a small opening. The oil that 
flows the fastest has the least viscosity. In some parts of the automobile 
it is necessary to use oil with less viscosity than in other parts. Tight 
fitting bearings should use oil with very little viscosity, while meshed 
gears should have semi-solid lubricants because the pressure on the 
rubbing surfaces is very high. 

77. Flash Point.^-The flash point is the temperature at which, if an 
oil be heated and a flame held over the surface, the- vapor rising from the 
oil will burst into flame, but will not continue to burn. A thermometer 
is placed in the oil bath and the temperature taken at this point. 

78. Fire Test and Cold Test. Fire test is merely a continuation of the 
flash point test; that is, the temperature at which the vapor which rises 
from the oil will continue burning, and not merely flash for a second. 
Both these tests are used only on cylinder oil. 

There is another test that is called the "cold test," which indicates 
the temperature at which the oil hardens, or becomes so stiff as not to 
flow. Good cylinder oil should not become so stiff as to prevent reaching 
the desired points at zero temperature. 

79. General Notes on Lubrication. There is no one thing which is 
the primary cause of more trouble and the cause of more expense 
in maintenance to the mechanism of an automobile than insufficient 

All moving parts of a car are usually manufactured with a high degree 
of accuracy and the parts are carefully assembled. In order to maintain 
the running qualities of the car it becomes necessary to introduce sys- 
tematically suitable lubricants between all surfaces which move in con- 
tact with one another. 


The special object of this chapter is to point out the places in the car 
which require oiling. While it is manifestly impossible to give exact 
instructions in every instance as to just how frequently each individual 
point should be oiled or exactly how much lubricant should be applied, 
we can give this approximately, based on average use. 

It should be borne in mind that friction is created wherever one 
part moves upon or in contact with another. Friction means wear, and 
the wear will be of the metal itself unless there is oil, and oil is much 
cheaper than metal. The use of too much oil is better than too little, 
but just enough is best. 

Proper lubrication not only largely prevents the wearing of the parts, 
but it makes the car run more easily, consequently with less expense for 
fuel and makes its operation easier in every way. 

The oiling charts shown in this chapter indicate the more important 
points which require attention. But do not stop at these. Notice the 
numerous little places where there are moving parts, such as the yokes 
on the ends of various connecting rods, and pull rods, etc. A few drops 
of oil on these occasionally will make them work more smoothly. 

Oil holes sometimes become stopped up with dirt or grease. When 
they do, clean them out and be careful not to overlook them. Also be 
careful not to allow dirt or grit to get into any bearings. 

Judicious lubrication is one of the greatest essentials to the satisfac- 
tory running and the long life of the motor car. Therefore lubricate, and 
lubricate judiciously.' 

The auto engine should be lubricated by some means that will insure 
a definite supply of lubricant to the moving parts and that will supply 
the loss caused from vaporizing, burning and leakage. 

The differential, axle bearings and shift gears are lubricated with semi- 
solid grease. The rear axle is not oil-tight, and therefore a fluid oil 
should not be used. Semi-solid lubricants also help to cut down the 
noise and wear where the pressure is heavy, and have sufficient cushion so 
that they adhere to the gear teeth. The lighter oils are better adapted 
for the high speed close-fitting parts. Other moving parts may be 
lubricated with the ordinary oil can, but are generally lubricated by the 
compression cup system. These cups may be screwed up from time to 
time to add more lubricant to the bearing surfaces. 

The transmission should always contain sufficient lubrication to bring 
it up to the level of the drain plug on the side of the case, or so that the 
under teeth of the smallest gear will enter to their full depth. 

The differential case should contain enough lubricant to bring it up 
to the filling hole, or should be about one-third full. 

Wheel bearings should be packed with a thin cup grease. Do not 
use a heavy grease because it will work away from the path of the roller 


or ball and will not return. In each hub there is usually a small oil hole. 
Inject some engine oil here whenever you are oiling the car. It will keep 
the grease soft and in good condition. Before lubricating any part, 
wipe all dirt from it so that the dirt will not get into the bearings. 

The steering gear is perhaps one of the most important parts of the 
car to keep properly lubricated. Failure of the steering apparatus is a 
dangerous thing and a few drops of oil given to the oil cups and the 
various steering connections constitute a cheap and safe means of avoid- 
ing accidents. Most types of steering apparatus are packed with grease 
which, having no outlet, will remain. However, the grease will become 
dry and a little oil should be added from time to time. 

Few motorists think of lubricating their brake connections. Mud 
and water will find their way into the brake mechanism and a squeeze of 
the oil can and a turn of the grease cups, given daily will keep them in 
good working condition. 

The principal engine lubricating systems can be grouped under the 
following heads: first, splash system; second, splash with circulating 
pump, which maybe either a "forced feed" or a "pump-over" system; 
third, full forced feed; fourth, mixing the oil with the gasoline. 

80. Splash System of Engine Lubrication. The splash system is used 
in the Ford engine, as shown in Fig. 119. The oil is poured directly into 
the crank case until it comes above the lower oil cock. The level of the 
oil should be maintained somewhere between the two oil cocks. The 
flywheel runs in the oil and picks up some of it and throws it off by cen- 
trifugal force; some of the oil is caught in a tube and carried to the front 
end of the crank case where it lubricates the timing gears. As the oil 
flows back to the rear part of the crank case, it fills the small wells in the 
crank case under each connecting rod. As the connecting rod comes 
around, a small spoon or dipper on the bottom scoops up the oil, so that 
there is a regular shower of oil all the time. The pistons, cylinder 
walls, and bearings are lubricated in this manner and the oil is kept in 
continuous circulation. All parts of the clutch and transmission are 
lubricated in the same manner as the engine. 

The oil level should never get below the lower oil cock and should 
never get above the upper oil cock. Never test the level of the oil when 
the engine is running. 

81. Splash System with Circulating Pump. This system has an oil 
reservoir or sump below the main crank case bottom. The oil from 
the sump in the lower half of the crank case is sucked through a strainer 
into the pump, usually at the rear end of the reservoir. The oil pump 
of the Buick engine is shown in Fig. 120. This pumps the oil up through 
a pipe to a sight feed on the dash so that the circulation can be observed 
by the driver. From here the oil returns to the splash trays in the lower 




half of the crank-case through the distributor pipe. As the crank comes 
around, the spoons or dippers on the connecting rods dip into these 
trays and force some of the oil up into the crank pin bearings and splash 
the remainder over the interior of the crank case and up into the cylinders 
and pistons. As the oil drains back, it is caught in ducts and led to all 
the bearings of the motor, the excess running back into the sump to be 
used again. 

The oil circulating pump consists of two small gears enclosed in a 
close fitting housing attached to the lower half of the crank case and 

driven by a vertical shaft and spiral 
gears from the cam shaft. As the gears 
turn, they take the oil into the spaces 
between the teeth and carry it around 
to the outlet where the action of the 
teeth meshing together squeezes the oil 
out of the spaces and forces it to flow to 
the sight feed on the dash. The pump 
requires no attention or adjustment ex- 
cept the addition of fresh oil to the 
crank case reservoir as often as is 
necessary to keep the oil level up to the 
oil cock. The sight feed on the dash 
merely shows whether or not the oil is 
circulating and does not show when the 
supply in the crank case is running low. 
Test the oil level at frequent intervals 
by opening the oil cock and see that the 
oil is kept up to this level. To remove 
the pump, draw off all the oil and take 
the pump out from below. 

The motor lubrication on the Overland car is shown in Fig. 121, ' 
and is the splash and pump-over system. The oil reservoir is located 
m the bottom of the crank case and is filled through the combination 
breather pipe and oil filler on the right side of the engine. The glass 
gauge on the side of the crank case close to the breather pipe indicates the 
oil level. The oil pump, which is located in the rear of the crank case, is 
driven from the cam shaft. The lubricant is drawn from the base and, 
after passing through a strainer, runs through a sight feed on the dash, 
and from there it runs into the troughs and is splashed into the bearing 
surfaces. It is very important that the oil strainer be kept clean at all 
;imes so that proper circulation of the 'oil is insured. For this reason 
B removal of the oil strainer has been made easy. By unscrewing the 
large plug on the side of the crank case right opposite the oil pump, the 

FIG. 120, Buick oil pump. 



cylindrical screen may be drawn out 'and cleaned by dipping into a pail 
of gasoline. The^ owner should see that the oil screen is cleaned every 
200 miles of the first 1000 miles and after that every 500 miles. 

The lubricant circulates freely through the system as long as the small 
wheel in the dash sight-feed revolves. But as soon as the wheel stops 
or the sight-feed glass shows clear, this is an indication that the oil supply 
is exhausted, or that there is an obstruction in the circulation of the 
oil which should be located and remedied immediately, since serious 
and expensive trouble will result from running the motor with an in- 
sufficient supply of oil. 

FIG. 121. Overland splash system with circulating pump. 

The wrist pin is lubricated from the cylinder walls, through the 
opening in the piston through which the wrist pin is inserted, as well as 
through a slot cut into the connecting rod over the wrist pin bushing. 

The lubrication system of the Studebaker Four, Fig. 122, is called 
the constant level splash system combined with a forced feed to. the 
timing gears. A quantity of oil is carried in a reservoir F, which is 
formed by the crank case of the motor. A pump B of the plunger type 
draws the oil from this reservoir and sprays it (G) over the connecting 
rod bearings. It also pumps surplus oil through a sight feed J or indi- 
cator on the dash, from which it flows over the timing gears D at the 



front of the motor and returns to the reservoir through the pipe U. 
The oil draining from the spray collects in troughs E which maintain a 
constant level of oil just under the connecting rods. At each revolu- 
tion short projections M from the connecting rods dip into these troughs 
and splash oil over the lower ends of the pistons, and over the cam and 
crank shaft bearings. 

To fill the oil reservoir of the motor, pour the oil in through a funnel 
shaped tube H, which you find on the left side of the motor. This 
funnel shaped tube is called the "breather pipe." At the side of the 
"breather pipe" there is a gauge / which shows the amount of oil in the 

FIG. 122. Studebaker splash system with forced feed. 

reservoir. The' oil is poured into the breather pipe until the gauge 
indicator rises to the highest point of the gauge, being careful that there 
is no more oil poured into the motor than just enough to bring the in- 
dicator to the highest point shown on the gauge. The only attention 
necessary to keep the motor perfectly lubricated is to see that the gauge 
indicator shows that there is oil in the reservoir. 

When the motor is running, oil drops through a glass indicator or 
"sight feed" J on the dash. This "sight feed" can be seen from the 
seat. and should not be forgotten by the driver. If the oil should cease 
to flow through the "sight feed" when the motor is running, the motor 
should be stopped and hood lifted to ascertain if the gauge I shows 
oil in the reservoir. If it does show oil in the reservoir, then either the 
oil pump or the connecting oil pipes are clogged and should be cleaned 



82. Full Forced Feed System. A full forced feed as used on the 
Cadillac Eight is shown in Fig. 123. A gear pump located at the for- 
ward end of the motor and driven from the crank shaft takes the oil up 
from the oil pan in the lower part of the crank case and forces it through 
a reservoir pipe running along the inside of the crank case, from which 
pipe there are leads to each of the main bearings. The crank shaft and 
webs are drilled and oil is forced from these main bearings to the con- 
necting rod bearings through the drilled holes. The forward and rear 
bearings supply the rod bearings nearest them, while the center bearing 


FIG. 123. Cadillac forced feed oiling system. 

takes care of the rod bearings on either side of it. The oil is then forced 
from the main reservoir pipe up to the relief valve, which maintains a 
uniform pressure above certain speeds, and overflows from this valve to 
a pipe extending parallel with the cam shaft and above it. Leads from 
this latter pipe carry lubricant by gravity to the cam shaft bearings and 
front end chains. Pistons, cylinders and piston pins get their oiling by 
the oil thrown from the lower ends of the connecting rods. 

A gauge indicating the level of the oil is attached to the upper cover 
of the crank case. Whenever the indicator reaches the space marked 
"fill," oil should be added until the indicator returns to "full." A filling 
hole is provided in each block between the second and third cylinders. 
If the hand on the pressure gauge on the cowl vibrates or returns to zero 
on the dial when the engine is running, it indicates that the oil level is very 


low. Should this occur through neglect to add oil at the proper time, the 

engine should immediately be stopped and sufficient oil added to bring 

the pointer up to the top of the gauge before the engine is again started. 

The hollow crank shaft oiling system as used by the Wisconsin Motor 

Mfg. Co. is shown in Fig. 124 and 
operates as follows: 

The oil is carried in an inde- 
pendent chamber at the bottom 
of the crank case, and the con- 
necting rods are not allowed to dip 
into this, thus preventing the oil 
from being whipped to a froth, 
and preserving its viscosity. 

It is pumped by means of a 
gear pump located at the lowest 
point of the oil reservoir into a 
main duct, which is cast integral 
with the crank case, and from here 
distributed by means of ducts, 
drilled into the webs, to the main 
bearings. From here it is forced 
through a hollow crank shaft to 
the connecting rod bearings, and a 
sufficient amount of oil is forced 
out of the ends of the bearings to 
lubricate the pistons, piston pins, 
and cam shafts. A separate lead 
runs directly over the timing gears, 
and all oil is thoroughly filtered 
before it is pumped over again. 
An oil gauge indicates by means of 
a ball and float the exact amount 
of oil contained in the reservoir, 
and distinct marks on the glass 
gauge show the high and low mark, 
and if the oil is maintained be- 
tween these two levels no burnt 
oil smoke will be emitted, and the 
spark plugs will not be fouled. 

The pressure of the oil increases with the speed of the motor, so the 
faster the motor is run the more oil is forced to it, and vice versa. The 
location of the oil reservoir permits the proper cooling of the oil, thus 
minimizing the danger of burning out bearings. 


The lubricating system for Knight sliding sleeve motors is also of the 
forced feed type. The following description is of the system used on the 
Moline-Knight car. Oil is drawn from the sump by a gear pump driven 
off the end of the eccentric shaft, and is delivered to the three main bear- 
ings, and the magneto drive shaft bearing under a pressure determined 
by the settings of a spring controlled by-pass valve, through which the 
excess oil is delivered. This excess oil is led to the chain driving the 
eccentric shaft and magneto, and flows thence to a trough and through a 
screen to the sump. Part of the oil delivered to the main bearings passes 
through holes in the crank shaft web to the crank pins, and thence through 
the tubular connecting rod to the hollow piston pins. From the two 
ends of the latter it flows to the sleeves and is distributed through holes 
and oil grooves in the latter over their circumference and the cylinder 
walls. All parts requiring lubrication not mentioned above are oiled 
by splash from the crank shaft and connecting rods. The flow of oil 
delivered under pressure is determined by a valve which is so connected 
as to open and close with the throttle. There are no oil grooves in any of 
the crank shaft bearings. The entire bottom of the crank case is covered 
by a screen, through which the oil returns to the sump. 

83. Mixing the Oil with the Gasoline. Another system that is used 
to some extent in two-stroke marine engines is to mix the lubricating oil 
with the gasoline, in the proportion of 1 pt. of oil to 5 gal. of gasoline. 
The easiest way is to thoroughly mix 1 pt. of oil with 1 gal. of gasoline, 
pour it into the fuel tank and then add 4 gal. of gasoline. The oil stays 
in solution with the gasoline. This system is very simple, as the lubri- 
cating becomes automatic and there are no regulators to adjust. 

When the piston is on the up stroke, a charge of gasoline and oil is 
drawn through the carburetor. Here the oil and gasoline separate 
because the oil does not evaporate and the gasoline does. The gasoline 
mixes with the air in the form of a gas. The oil collects in the form 
of small globules which float in the mixture of gas and air and are carried 
into the crank case by the suction of the motor. Here some of the oil 
settles on the connecting rod and crank and flows through a special oil 
duct to the crank pin. 

On the down stroke of the piston, the gas and oil are forced through 
the by-pass into the cylinder where the remainder of the oil is deposited 
on the cylinder walls. This operation' is repeated every revolution of 
the engine, a new film of oil being supplied each time. 

84. Selection of a Lubricant. The proper lubrication of the motor 
car is more important than any other item in its care. Only the best 
high grade oils should be used to lubricate the engine. Some engines 
require lighter oils than others on account of the close-fitting pistons and 
rings. It is better to follow the instructions sent out by the manufac- 


turers in regard to the kind of oil to use rather than for the motorist to 
make his choice or to be directed by an oil salesman. The different com- 
panies run extensive tests and find out in that way which oil is best suited 
for their type of engine. The only way to get the best lubricants is to pay 
the price. Money saved by cheap oils or grease may be more than lost 
in worn-out bearings or cylinders. 

The multiple-disc type of clutch is the only one in which any lubrica- 
tion should be used, and the oil here should be drained off about every 
1000 miles, the clutch well cleaned out with kerosene, and then filled with 
light machine oil, the amount, of course, depending upon the capacity 
of the case. All clutches that use any kind of facing, such as asbestos, 
raybestos, or leather, should never be lubricated, as the oil decreases the 
friction and causes slipping. Clutch leathers will retain their life and 
softness better if given an occasional treatment of neatsfoot oil and then 
wiped dry. 

The planetary transmission system in the Ford automobile is encased 
so as to revolve in an oil bath. 

The differential housing and sliding gear transmissions and all other 
parts that use either heavy cylinder oil, transmission oil, or graphite 
grease, should be thoroughly cleaned every 1000 miles, or thereabouts, 
and well flushed out with kerosene in order to remove all sediment and 
metallic dust that may be in the old grease. All wheel bearings are of 
the ball or roller anti-friction type, and are packed with semi-fluid 
grease which should be renewed about every 1000 miles. 

An excess of grease in the transmission or differential case will be shown 
by leaking at the joints, on account of the difficulty of keeping these 
members absolutely tight and still free to run. If there is too much 
grease in the differential case, it will run along the axle shaft and out over 
the oil guard, which is to prevent it from getting on the tire and also from 
interfering with the action of the internal brake. 

Excess of lubrication in the engine will produce carbon deposits and 
dirty spark plugs. It may also cause the piston rings to gum up and stick. 
It can be detected by the color of the exhaust smoke, which will have a 
bluish tinge, or it may be detected by a sticky black coating on the spark 

A small amount of graphite and oil or grease should be supplied be- 
tween the leaves of the springs. This can generally be done by jacking 
up the frame so that all weight is taken off the wheels, and by using 
a small clamping device with wedge-shaped jaws, which can be used to 
spread the leaves apart. 

85. Directions for Lubrication. A very good chart for lubrication 
purposes is sent out by the Chalmers Motor Car Co., and of course can 
be used for other standard makes of cars. This chart is as follows: 






Crank case. 

Steering knuckle grease cups. 
Steering cross rod grease cups. 
All spring bolt grease cups. 
Speedometer driving gears. 
Eccentric bushing of steering gear. 
Wheel hub oilers. 


Keep oil at level of top try cock. 
One complete turn. 
One complete turn. 
Two complete turns. 
One complete turn. 
10 or 15 drops. 
10 drops. 


Part Quantity 

Fan hub bearing. Few drops. 

Pump shaft grease cups. Two complete turns. 

Steering gear case oiler. Fill. 

Steering gear case grease cup. Two complete turns. 

Steering wheel oil hole. 8 or 10 drops. 

Steering column. 10 or 15 drops. 



Spark and throttle shafts. 

Control bracket bearings. 

Transmission case. 

Pedal fulcrum pin. 

Brake pull rods and connections. 

Brake cross rod grease cups. 

Torque rod grease cups, front and rear. 

Brake shafts on rear wheels. 

Rear spring perch grease cups. 

Few drops. 

Enough to cover lower shaft. 
Two complete turns. 
Two complete turns. 
Two complete turns. 


Part Quantity 

Magneto bearings (3 oil holes). 3 or 4 drops each. 

Dynamo drive shaft universal joints. Fill one-half full. 

Motor oil. 
Cup grease. 
Cup grease. 
Cup grease. 
Cup grease. 
Motor oil. 
Motor oil. 

Motor oil. 
Cup grease. 
Motor oil. 
Cup grease. 
Motor oil. 
Motor oil. 

Motor oil. 
Motor oil. 
Motor oil. 
Motor oil. 
Motor oil. 
Cup grease. 
Cup grease. 
Motor oil. 
Cup grease. 


High grade light ma- 
chine oil. 
Cup grease. 

Crank case. 

Reach rod boots. 

Spring leaves. (Jack up frame and 

pry leaves apart.) 
Hub caps. 
Universal joints. 

Gasoline pressure hand pump. 

Drain off dirty oil; clean oil screen at 

left of motor thoroughly; fill to 

level of top try cock. 
Pack thoroughly. 

Pack thoroughly. 

Remove grease hole plug and fill one- 
half full. 
4 or 5 drops on leather plunger. 

Motor oil. 


Graphite grease. 

Cup grease. 
Cup grease. 

Light machine oil. 



Differential housing. 
Transmission case. 



Drain thoroughly, flush with kero- 
sene, refill to cover top lower 
shaft try cock. 


Special axle compound. 
Motor oil. 1 

Dynamo should be lubricated every 3000 to 5000 miles. 

When changing tires, put a few drops of oil on inside sliding ring of demountable rims to insure easy 





Figure 125 shows the location of the various places to be lubricated 
and the proper intervals for lubrication. This is the chart for the Case 

86. Cylinder Cooling. When an explosion occurs inside the cylinder 
of a gas engine, the gases on the inside reach a temperature of from 2000 
to 3000F. The walls of the cylinder are, of course, exposed to this high 
heat and would very quickly get red hot if we did not have some way of 
keeping them cool. The polished surface upon which the piston slides 
would be very quickly spoiled. The most common way of keeping a 
cylinder cool is by the use of water. Surrounding the cylinder is a metal 
jacket enclosing a space for the cooling water. By keeping a supply of 
water passing through this space, the cylinder can be kept cool enough 
for the operation of the engine. The cylinder head is also cast with a 
double wall, especially around the valves, so that these parts will also be 
kept cool. The cooling fluid used is generally water. 

Water should not be allowed to remain in the jacket of an engine over 
night if there is danger of a frost, as the freezing of the water will crack the 
cylinder. When the supply of water is limited, as in an automobile, 
the water is cooled in a radiator or system of pipes, and then is used over 
again. The water is kept in circulation by a pump, or by the thermo- 
syphon system, and the hot water is cooled by the air passing over the 

The circulation in the thermo-syphon system is based on the fact that 
cold water is heavier than hot water, and consequently, the water heated 
in the cylinder jackets flows up and over into the top part of the radiator, 
where it is cooled and then flows from the lower portion of the radiator 
back to the engine cylinder. Circulation is automatically maintained as 
long as the engine is hot and there is enough water in the radiator so that 
the return connection from the cylinder to the radiator contains water. 
This means that the radiator must be kept practically full all the time, or 
else there will be no circulation and the water will merely boil away. 

When the pump system of circulation is used, the radiator may be 
lighter than in the syphon system, as less water is needed to do the same 
amount of cooling. The pump is driven from the engine, and the faster 
the motor runs the faster the water circulates. The centrifugal type of 
pump is generally used for circulating cooling water. 

87. Water Cooling Systems. Radiators differ in design. In some 
types the water flows through tubes of very small diameter. In this 
type it is necessary to have a circulating pump of some kind. In radia- 
tors having tubes of larger diameter, the thermo-syphon system may be 
used. The radiators using the small pipes have a greater capacity for 
their size because they have more exposed area for cooling in comparison 
with the amount of water they carry. The small tubes have the dis- 


advantage of increased resistance. This is why it is necessary to use a 


The air for cooling purposes is usually drawn through the radiator 
by a fan placed directly back of it. This fan may be driven with a bevel 
or spur gear, with a silent chain, or with a wire or leather belt. In some 
cases, however, the engines are air-cooled, the cylinders being cast with a 
large 'number of fins or rings on the outer surfaces to increase the cooling 
effect of the air. In this case there is no water jacket. 

The cooling system of the Overland is the thermo-syphon system, 
which eliminates the circulation pump and its gears, glands, stuffing boxes, 

FIG. 126. Overland thermo-syphon cooling system. 

etc. The thermo-syphon system is automatic, as the speed with which 
the cooling water circulates is increased or decreased with every increase 
or decrease in jacket temperature. The action of the system is, briefly, as 
follows: The water enters the cylinder jackets A, Fig. 126. Upon 
becoming heated by the explosions within the cylinders, the water ex- 
pands and, being lighter, rises to the top. It then enters the pipe B and 
passes into the radiator at C, where it is brought into contact with a large 
cooling surface, D, in the shape of the cellular radiator. On being cooled, 
and thereby contracting and becoming heavier, the water sinks again to 
the bottom of the cooling system, to enter the cylinders once more and to 
repeat its circulation. The cooling action is further increased by a belt- 
driven fan which draws air through the radiator spaces. 



Figure 127 shows the cooling system on the Ford. This is also a 
thermo-syphon system, the principle of operation being the same as on 
the Overland. The arrows indicate the path of the cooling water. 

The cooling system used on the Studebaker Four is the pump system 
shown in Fig. 128. The water system, which contains 10 qt. of water, 
consists of a radiator, hose connections, water line, pump, and water 
jackets which are incorporated with the cylinders. The radiator D 
being filled with water and the motor running, the centrifugal pump C 
forces the water to circulate as follows: From the pump it is driven 

FIG. 127. Ford cooling system. 

through the lower water line into the cylinder water jacket, directly at 
the valve seats, where perfect cooling is most needed. Here it absorbs 
the heat and goes on to the upper water line and thence to the radiator. 
In the radiator D the water percolates slowly down through many fine 
tubes F and is cooled by the air rushing between the fins surrounding the 
tubes and thence returns to the pump. A fan G on the front of the 
motor, belted to the crank shaft, draws the air through the radiator and 
facilitates the cooling operation. Figure 128 also shows a standard 
design of tubular radiator. The pump, which is of the centrifugal type, 
requires no attention other than to see that it does not become choked 
by using dirty water. There is a packing nut on the shaft which should 
be repacked if the pump should ever leak around the shaft entrance. 


This can very easily be done by turning off the packing nut, removing the 
old packing and rewinding the shaft with a few inches of well graphited 
packing and tightening up the packing nut. The packing should be 
wound on in the same direction as the nut is turned to tighten it. 

The cooling system on the Cadillac Eight is of the forced circulation 
type. The radiator is of the tubular and plate type, with rotating fan 
mounted on the forward end of the generator driving shaft, the latter 


FIG. 128. Studebaker cooling system. 

being driven by silent chain from the cam shaft. Each set of cylinders is 
cooled separately. Due to the angle of jackets, the water does not lodge 
in the pockets. The natural tendency is for the water to flow upward 
and to rise to the hottest points. 

There are two centrifugal water pumps, one on each side of the 
forward end of the engine. These are driven by a transverse shaft which 
is driven by spiral gears from the crank shaft. Within each pump hous- 
ing is a thermostat shown in Fig. 129, which controls a valve that is 
between the radiator and the pump. 

When the temperature of the cooling water drops below a pre- 
determined temperature, the thermostats contract, thereby closing the 



valves. The water is then circulated only through the cylinder blocks 
and the carburetor jacket. It returns to the pumps through the water 
jacket on the intake manifold and carburetor. When the thermostats 
are closed, none of the water circulates through the radiator the evapora- 
tion of the gasoline in the carburetor and manifold providing sufficient 
cooling action. As the temperature of the water rises, the thermostats 
expand, thereby gradually opening the valves, permitting the water to 
circulate through the radiator. 



FIG. 129. Cadillac thermostatic control of cooling water. 

The advantage in this device is that, in starting with a cold en- 
gine, the engine is brought to a point of highest efficiency, in so far as 
heating is concerned, much more quickly than if it were necessary to 
heat the entire volume of water before reaching that efficiency. With 
the usual water circulating system, the highest efficiency of the engine 
is not reached in extreme cold weather. An engine uses its gasoline 
most economically when it is running rather warm, and with a radiator 
which is adequate to prevent overheating in hot weather, the cooling 
is too great for best economy in extreme cold weather. 

The Cadillac thermostat is simply a small corrugated copper tube 
containing a liquid which expands or contracts in accordance with the 
temperature, thus slightly lengthening or contracting the tube, its total 
movement being 34 in. This thermostat is in connection with a valve 
so that, when it expands, it raises the valve from its seat, this valve con- 
trolling the flow of water to the radiator from the pump. A by-pass 



connects with the water jacket of the carburetor, and when the engine 
is started, the water is naturally cold. Therefore the thermostat is 
contracted and its valve is seated. Thus the radiator water is shut off, 
the circulation being simply through the water jackets of the cylinders, 
through the by-pass to the carburetor jacket and thence back to the 
cylinders. There is thus only a small part of the water circulating, and 
when this heats up, the thermostat begins to expand and lifts its valve 
from its seat, letting the radiator supply flow into the system. This 
action continues back and forth so that the water temperature is nearly 

88. Air Cooling. The Franklin engine, shown in Fig. 130, shows a 
good design of an air cooling system. The direct air cooling of the engine 

FIG. 130. Franklin air cooling system. 

is accomplished as follows: The individual cylinders are provided with 
vertical fins projecting from their periphery. The fins on each cylinder 
are surrounded by sheet metal jackets which form passages for the air. 
The flywheel is provided with a number of curved blades so that it has a 
blower effect whenever the engine is running. This forms a partial 
vacuum and sucks air into the space underneath the hood through the 
grille in front. This air passes in uniform quantities down through the 
individual jackets on each cylinder into the compartment below the 
engine deck and hence out through the fan blades. The fan is incor- 
porated in the flywheel and driven directly by the engine; so a steady 
stream of fresh air is being continually drawn down over the cylinders 
as long as the engine is running. 


89. Cooling Solutions for Winter Use. In climates where the tem- 
perature does not go below a dangerous freezing point, the cooling 
medium used is water; but in cold regions, where cars are run a good 
deal in the winter, it is necessary to get spme kind of anti-freezing 
solution. The ideal requirements for an anti-freezing compound are 
as follows: 

1. It should have no harmful effect on any part of the circuit with 
which it comes into contact. 

2. It should be easily dissolved or combined with water. 

3. It should be reasonably cheap. 

4. It should not waste away by evaporation, that is, its boiling point 
should be as high as that of water. 

5. It should not deposit any foreign matter in the jackets or pipes. 
The principal materials used are: (1) oil; (2) glycerine; (3) calcium 

chloride; (4) alcohol; (5) mixture of alcohol and glycerine; (6) kerosene 

Oil has the advantage of having a very high boiling point so that 
it will not waste away, but it has the disadvantage that it does not 
make a good mixture with water, and will not absorb heat as rapidly as 
water. It also has a lower heat coefficient, that is, it takes less heat to 
raise the temperature of a certain amount of oil one degree, than it does 
the same amount of water. Oil cannot be used where there is any rubber 
in the circuit. It will attack rubber hose and gaskets very quickly and 
they will deteriorate rapidly. 

The disadvantages of using glycerine are similar to those of the 
oil, chief of which is sure destruction to the rubber connection. It also is 
liable to contain free acids, and it is quite expensive. 

Calcium chloride makes a very good solution with water, the freezing 
point depending upon the proportions used. The general solution is to 
use 5 Ib. of the salt to 1 gal. of water. This solution will stand 39 below 
zero before freezing. It has the disadvantage of being very apt to cause 
electrolytic action where two metals are joined together. It is derived 
from hydrochloric acid, and is liable to contain free acids, which attack 
the metal very rapidly. Calcium chloride has the same appearance as 
chloride of lime, but has a somewhat different chemical composition. 
Pure calcium chloride is the only thing that can be used. The com- 
mercial chloride of lime sets up electrolytic action. The solution may 
be tested for acid by dipping a piece of blue litmus paper in it. If there 
is any acid present, the paper turns red. As the water is evaporated in 
the radiator there will be a crust formed on the inside of the jacket, and 
also in the pipes, which has a tendency to clog up and prevent circulation. 
The rate at which these deposits occur depends on the strength of the 


Denatured alcohol seems to be about the best substance to use as a 
non-freezing solution, as it has no destructive action whatever on either 
metal or rubber, makes no deposits and never causes electrolytic action. 
A solution of 50 per cent water and 50 per cent alcohol will stand about 
32 below zero. The only disadvantage that it has is that it evaporates 
more readily than the water, so that when adding new solution, more 
alcohol than water must be added in order to keep the solution of the 
same strength. The combination of alcohol, glycerine and water seems 
to give very good results. In this combination, equal parts of alcohol 
and glycerine are used. The alcohol has a tendency to overcome the 
destructive action of the glycerine or the rubber connections, and the 
glycerine keeps the alcohol from evaporating too rapidly. The freezing 
point depends on the strength of the solution. A solution of 60 per cent 
water, and 20 per cent each of alcohol and glycerine freezes at 24 below 
zero. The proportions must be governed by the locality in which they 
are used. 

There are also numerous anti-freezing compounds on the market. 
These are mostly put up from some of the materials mentioned here. 

In the following tables are results showing the temperature at which 
some of the well known anti-freezing solutions will freeze, in various pro- 
portions of mixture with water and with one another. These are neces- 
sary, as different localities and different altitudes require different solu- 
tions and every person should be able to select his solution in the right 
proportion to avoid having any trouble in the coldest possible weather 
likely to be experienced in his home location. 


Per cent by volume of Specific gravity of Frppzini? noint 

calcium chloride solution 















- 18F. 



- 28F. 



- 42 F. 


specific gravity is 

given to be used 

as a check on 



Per cent by volume of 

Specific gravity of 

Freezing point 












- 20F. 



- 32 F. 



- 45F. 



- 57F, 



If wood alcohol be used instead of denatured alcohol, slightly lower 
temperatures can be reached with the same proportions of alcohol and 


Alcohol and glycerine Water Freezing point 

15 per cent 85 per cent 20F. 

25 per cent 75 per cent 8F. 

30 per cent 70 per cent 5F. 

35 per cent 65 per cent 18F. 

40 per cent 60 per cent 24F. 

45 per cent 55 per cent 30F. 

50 per cent 50 per cent - 33F. 


All automobile engines in use at the present time have some form 
of electric ignition, in which a current of electricity is made to produce a 
spark inside of the cylinder. All ignition systems are made up of two 
essential parts: (1) the source of electric current supply; and (2) the 
apparatus for utilizing this current to produce a spark in the cylinder. 

Before considering the features of either of these component parts 
it is necessary that an understanding be had of the fundamental electrical 
principles and definitions governing the construction and operation of 
electric ignition systems. 

90. Fundamental Electrical Definitions. An electric current flow- 
ing in a wire can be compared to water flowing in a pipe line. As the 
water pressure is measured in pounds per square inch, so the electrical 
pressure in a wire is measured by a unit called a "Volt." It is the practical 
unit by which electrical pressures are measured. 

The "Ampere" is the practical unit by which the rate of current flow 
in a wire is measured. It corresponds to the number of cubic feet or 
gallons which flow through a water pipe per unit of time. For a large 
number of amperes, a large wire is necessary and for a smaller number 
of amperes, a smaller wire can be used. We can have a small wire carry- 
ing a current of high voltage, and a large wire carrying current of low 
voltage, just the same as a large or small pipe can carry water of either 
high or low pressure. The size of wire determines the quantity of current 
it can carry. A small wire can carry a small current but it requires a 
large wire to carry a large current. 

The "Ohm" is the unit by which the resistance to the flow of electric 
current through a wire is measured. It corresponds to the friction op- 
posing the flow of water through a pipe. 

The Ampere-hour is the measure of quantity of current. One 
ampere-hour is the amount of current which would flow at the rate of 
1 amp. in 1 hour. It is by this unit that the capacity of storage batteries 
is measured. A 60 ampere-hour battery will give current at the rate of 
60 amp. for 1 hour, or at the rate of 30 amp. for 2 hours, or at the rate of 
1 amp. for 60 hours, etc. 

91. Direct and Alternating Current. Electric current can be of two 
kinds : direct or alternating. Direct current always flows in one direction 
in the wire, and is the kind of current which is given out by every type 




of battery. Alternating current, however, first flows in one direction 
and then in the other, the reversals taking place many times per second. 
It is the kind of current given out by most of the modern magnetos. 

92. Dry Batteries. The first necessary part of an electric ignition 
system is the source of current. For this purpose we can have either 
batteries, dynamos, or magnetos. In this chapter only batteries and 
battery ignition systems will be discussed. Magnetos will be treated in 
the chapter on Magnetos. 

The dry battery is a common source of battery current for ignition 
purposes. It is comparatively cheap, exceptionally reliable, and can 
be easily replaced when worn out. Due to im- 
provements in the battery ignition systems its 
use for motor car ignition is growing, after hav- 
ing given way for a time almost entirely to 
magneto ignition. Figure 131 is a section of a 
commercial dry cell. It consists of a cylindrical 
zinc shell around the inside of which has been 
placed a piece of absorbent paper saturated with 
a paste made of zinc oxide, zinc chloride, am- 
monium chloride, plaster of Paris, and water. 
The zinc can forms the negative terminal of the 
battery, and the carbon element down through 
the center of the cell forms the positive terminal. 
The space between the absorbent paper and the 
carbon is filled with powdered carbon and 

manganese oxide which acts as a depolarizing agent. The voltage of a 
dry cell is about 1.5 volts. The maximum possible amperage or current 
of a new cell ranges from 20 to 35 amp., depending upon the size of the 
cell. The dry battery always gives out direct current. The capacity 
and life of a dry cell depends on the way it is used, being greater when 
it is used intermittently. 

93. Storage Batteries. Although the storage battery is to be con- 
sidered in Chap. VIII on Starting and Lighting Systems, a brief descrip- 
tion will be given here in order to bring out clearly its functions in battery 
ignition systems. A storage cell, Fig. 132, consists of two sets of metallic 
plates placed in a vessel containing a solution of sulphuric acid and 
water. In the positive group the plates are lead grids, the openings being 
packed with lead peroxide, characterized by its chocolate brown color. 
The plates of the negative group consist of finely divided sponge lead. 
These sets of plates are placed in the cell so that the positive and negative 
plates alternate and are separated by perforated sheets of hard rubber 
or specially treated wood. By passing direct current into the top of 
one of the plates, through the acid and water, and out the other plate, 

FIG. 131. Section of dry 



the plates are changed chemically. When the battery is used, the 
chemical change is reversed and the plates tend to return to their original 
state, giving off current as they do so. The single storage cell of one 
positive and one negative set of plates gives, when fully charged, a pres- 
sure of about 2 volts and a current depending upon the size and number 
of the plates. For ignition purposes the plates are connected so that the 
whole battery gives a voltage of from 6 to 8 volts and a capacity of 
from 60 to 80 ampere-hours. 

Expansion Chamber to 
take care of changes in 
Volume of Solution ' 
rluring Charge and Discharge 

Soft Rubbct 


Polished Hard 
Rubber Cover 

Battery Terminal covered 
with a layer of pure Para 
Rubber vulcanized Directly 
to the Corrugated Surface 
. of the Conductor to prevent 
creeping of acid. 

Plates and elements 

ofthe l 
.Villard Standard 
Faure' Type 

Treated Hardwood 
Case with Dovetail 


Quadruple . 
Plate or Element Supports 
of Hard Rubber 

FIG. 132. Section of Willard storage cell. 

94. Series and Parallel Connections. The voltage of either a dry or 
storage cell is not high enough for automobile engine ignition purposes, 
and methods of connecting several batteries must be resorted to in order 
to raise the voltage and amperage. A voltage of from 6 to 8 is necessary 
for an ignition system using an induction coil. This can be obtained 
by the connection shown in Fig. 133, in which the carbon of one cell is 
connected to the zinc of the next. This is known as the "series" con- 
nection. By so connecting the cells, the resultant voltage is equal to 
the combined voltage of all, or the number of cells multiplied by the 
voltage of one cell, which is 1.5. The current output is equal to the 
current of one cell of the given size, or about 20 amp. If all the carbons 
are connected and all the zincs fastened together, as shown in Fig. 134, 


the connection is known as "parallel." The resultant voltage equals 
the voltage of one cell and the current output equals the current output 
of one cell multiplied by the number of cells. Therefore, to increase 
voltage connect the cells in series, and to increase current output con- 
nect them in parallel. 

5 Dry cells in -series Dry cef/s in parallel 

FIG. 133. FIG. 134. 

95. Battery Connections for Ignition Purposes. Where the current 
demand is small or not continuous, a single series of cells (usually five) 
is used. This arrangement is suitable for single cylinder engines, or for 
starting engines of two or more cylinders, where a magneto is used after 
the engine is in operation. 

When the amount of current required is great, the multiple series 
connection is used. It is suitable for engines of two or more cylinders and 
continuous service. This arrangement 
consists of parallel groups of as many 
cells in a series as may be required for 
the service. Figure 135 shows an arrange- 
ment with three parallel sets, each of five 
cells connected in series. This arrange- 

'5 cells in multiple series arrangement . 

p iQ 13 - ment provides for an amperage of about 

60 at about 7K volts. 

Two series of cells in multiple series connection will have about 
three times the life of a single series on the same current, on account of the 
reduced rate of discharge. Three series connected in this manner will give 
about six times the life on the same current, as would one series. 

Another advantage of this method of connection is that a dead cell 
will not weaken the current from the group enough to interfere with the 
engine operation. For ordinary service, three groups of five cells each 
are frequently used, while for heavy, constant service five groups of five 
cells each, giving a voltage of about 7.5 and a current of about 100 amp. is 

96. Simple Battery Ignition System. The jump-spark or high-tension 
system of ignition is so named because a high tension current is caused to 
jump across the gap between the terminals of the spark plug in the cylin- 
der. Figure 136 shows an elementary battery jump-spark ignition system 
for a one-cylinder engine. Four dry cells are shown connected in series 
giving a voltage of about 6 and a current of about 20 amp. One terminal 
of the battery set is connected to the left terminal of the induction or spark 



coil and the other terminal to the engine "timer." The timer, or 
commutator, is nothing more or less than a mechanically operated 
"switch," placed between the batteries and the right terminal of the coil. 
The current from the batteries goes to the left terminal of the coil which is 
connected to a standard holding an adjustable contact serew. This 
screw is in contact with the vibrator. Passing from the screw into the 
vibrator, the current goes through a comparatively large wire wound 
around the central core. This wire goes to the right terminal of the coil, 
which is connected back to the timer. This circuit forms what is known 
as the "primary" of the system. When the timer completes the circuit, 


FlG. 136. 

current flows through the primary winding. The current flowing around 
the iron core makes a magnet of it. This fact causes the vibrator to be 
pulled away from the adjusting screw, and this breaks the circuit. 
Consequently, current ceases to flow, the core loses its magnetism, the 
vibrator flies back to make contact with the screw again, and this 
permits the primary current to flow, causing a repetition of events. The 
result is a constant dying down and building up of the current in the 
primary winding around the core. This results in a dying down and 
building up of the magnetism in the core. It will be noticed that there 
is another coil of finer wire wound around the primary coil on the iron 
core. This is called the "secondary" of the coil. The ends of this 
secondary winding are fastened to the two secondary terminals on the top 
of the coil. One terminal of the coil is connected to the spark plug in 
the cylinder and the other is connected onto the engine frame, or 

Each time the current in the primary circuit is broken, there is another 
current of very high voltage induced in the secondary winding. This 
current is of sufficiently high electrical pressure to jump the spark plug 
gap under the usual compression pressure. This voltage varies from 



10,000 to 20,000 volts. The relation between the voltage on the primary 
circuit and that on the secondary depends upon the relative number of 
turns of wire on the primary and secondary windings, upon the speed of 
the vibrator and the current in the primary winding. 

In the bottom of the coil is placed the condenser, consisting of alternate 
tinfoil and oiled paper sheets. Every alternate tinfoil sheet is connected 
to the bottom of the standard; the ends of the others are connected to the 
vibrator. The current tends to continue flowing after the circuit is 
broken and, if it were not for this condenser, there would be a fat spark 
across the vibrator points every time the circuit was broken. The 
condenser prevents this arcing across the vibrator points, when they break, 
by absorbing this flow of current and storing it until the circuit is again 
closed. In addition, it aids in the induction of the high tension current 
in the secondary winding of the coil by permitting the quick break of the 
primary current. 

The following are the names and functions of the various parts of a 
battery ignition system: 

Primary Circuit. That part of the system carrying the battery 
^ ^ current at low voltage a few turns 

Primary termindJ 

y ^~ ~~^ w*i Secondary Circuit. That part 

of the system carrying the high 
tension current to the spark plugs 
a great many turns of very fine 
wire on the coil. 

Timer. A mechanically oper- 
ated switch placed in the primary 
circuit. Its function is to com- 
plete the primary circuit and cause 
the vibrator to act, thus causing 
a high tension current to flow to 
the spark plugs at the proper 

Vibrator. A spring placed in 
the primary circuit to make and 
break the current, causing a high 
tension current in the secondary. 

Condenser. An electrical ap- 
pliance placed in the primary cir- 

Seconcfary terminal 

FIG. 137. Three terminal vibrating 
induction coil. 

curt to prevent sparking at the vibrator points. 

97. The Three Terminal Coil. Most of the coils used on automobile 
ignition systems have only three terminals instead of four. One end 
of the primary winding is joined to one end of the secondary and the 



junction to one of the terminal binding posts. The other end of the 
primary goes to a primary binding post and the other end of the secondary 
to the secondary binding post of the coil as shown in Fig. 137. An 

FIG. 138. Pfanstiehl three terminal coil. 



FIG. 139. Wiring diagram for four-cylinder engine. 

external view of a three-terminal coil for a single-cylinder engine is shown 
in Fig. 138. In Fig. 139 a four-unit coil with the wiring for a four-cylinder 
engine is shown. The three terminals are lettered: .S, the secondary 
terminal leading to the plug; P, the primary terminal to the timer; and B, 


the terminal connected to the batteries. The secondary circuit is from 
the secondary terminal to the plug, across the gap into the engine frame, 
back through the timer to the coil. The primary circuit is from the 
batteries, one side of which is grounded, through the coil, to the timer, 
where the circuit is grounded and the current returns to the batteries 
through the metal of the engine. 

FIG. 140. Pfanstiehl four-cylinder coil set. 


FlG. 141. 

Where a multiple cylinder engine is used, it is customary to use 
a coil for each cylinder. The coils are usually enclosed in an upright 
box as shown in Fig. 140, which is a coil set for a four-cylinder engine. 

In Fig. 141 is shown the arrangement of the ignition system for a 



four-cylinder engine using dry batteries as the source of current. There 
are two sets of batteries, one service set and a reserve set. The six cells 
are connected in series, giving a voltage of about 9. The four coils are 
placed in one box, with two small terminals at the bottom. Either of 
these terminals is a primary terminal for any one of the four coils and is 
connected to the two sets of batteries. The switch on the front of the 
box determines which set of batteries will be used. The other primary 
terminals at the top of the coils are connected to the four binding posts 
of the timer. These terminals are also secondary terminals. The large 
connections at the bottom of the coil box are secondary wires leading to 
the spark plugs. When the timer, which runs at one-half engine speed 
or at cam shaft speed, grounds the primary circuit by the roller making 
contact with the insulated terminal, a spark occurs in one of the cylinders, 
depending upon the position of the roller. Any of the four coils may be 
removed from the box for adjustment or repair. 

Pull Rod Connection 


Thumb Nut 

Contact Point 
Roller Arm 

Engine Cover 

FIG. 142. The Ford timer. 

98. Timers. Figure 142 shows the timer used on the Ford engine. 
The inside or rotating part is fastened to and rotates with the cam shaft. 
When the roller comes into contact with one of the terminals on the hous- 
ing, the circuit for that coil is closed and a current is caused to flow in 
the primary circuit, causing a spark in the secondary circuit. The 
housing does not turn with the cam shaft, but can be shifted back and 
forth, either advancing or retarding the spark. The timer is always 
placed in the primary circuit. 

The timers for six- and eight-cylinder engines are similar to the above, 
but have six or eight insulated terminals on the housing instead of four. 

99. Spark Plugs. The spark plug consists of two terminals fastened 
together, but insulated from each other, and the whole screwed into the 
cylinder. The center terminal is insulated from the rest of the plug 
and the other terminal. The insulation between the center electrode 
and the body of a plug is usually either of porcelain or of mica. The 


outside terminal is in contact with the engine cylinder and is consequently 
grounded. The only way the current can get from one terminal to 
another is across the air gap between them. The gap between points 
'of the battery spark plugs should be about % 2 in., 'or the thickness 

FIG. 143. J. M. soot-proof spark plug. 

FIG. 144. Bosch spark plug. 

of a smooth dime. Figure 143 shows the exterior and interior arrange- 
ment of the J. M. soot-proof plug. In Fig. 144 is shown the side and 
, " = bottom views of the Bosch plug with three 

~~->w grounded electrodes. 

100. Master Vibrators. In order to avoid 
the four vibrator adjustments on the four-coil 
systems, and the possibility of getting sparks of 
different intensity in the different cylinders, a 
master vibrator is sometimes used. A master 
vibrator is an additional coil with only a primary 
winding, one vibrator, and a condenser. It is 
placed between the batteries or source of cur- 
rent and the primary windings of the coils. 
The vibrators of the coils are then screwed down 
tight or short-circuited by a copper wire as 
shown in Fig. 146. The master vibrator serves 
for all four coils and, when once adjusted, the 
sparks in all the cylinders will be of the same 
intensity. There is only one vibrator to be 

adjusted and to get out of order instead of four. The principle of the 
master coil is that the winding of the coil and the vibrator are connected 
successively in series with the primary windings of each individual coil. 

FIG. 145. Pfanstiehl 
master vibrator. 



This produces the make and break in the primary winding of the coil. 
Figure 145 illustrates the outside view of the Pfanstiehl master vibrator. 
Figure 146 shows the application of the K-W master vibrator with both 
battery and magneto sources of current. 

FIG. 146. Connections for K-W master vibrator. 

101. The High Tension Distributor System. A typical high tension 
distributor system is shown in Fig. 147. This system enables a single 
coil to be used to serve a number of cylinders. The particular feature 
of this system is the combined low tension timer, or interrupter, and 
the high tension or secondary distributor, acting with a single non- 

FIG. 147. High tension distributor system. 

vibrating coil. In this particular illustration, two sets of dry cells are 
provided, one set being in reserve. The distributor and timer are usually 
mounted in a vertical position in a single unit and are driven at cam shaft 
speed by a vertical shaft. The coil, as mentioned before, is non-vibrating. 
The mechanical contact maker, or interrupter form of timer located 
under the high tension distributor, serves in place of the usual vibrator 
on the coil. 



The primary current flows out of the batteries into the bottom 
primary terminal of the coil, out of the center primary terminal and over 
to the primary binding post on the timer. The revolving contact maker 
completes the circuit by grounding the current through the timer shaft. 
This contact maker or timer is constructed so as to give a very quick 
break to the primary circuit so that there will be a high pressure current 
induced in the secondary winding of the coil. This flows out of the 

FIG. 148. Connecticut type E ignition system. 

secondary terminal of the coil to the main terminal post of the distributor, 
where it is sent to one of the four spark plugs, depending on the position 
of the distributor arm. The action of a distributor is much like that of 
an ordinary timer used with vibrating coils, though its construction to 
handle secondary high tension current is necessarily much different. In- 
stead of producing a series of sparks in the cylinder, as is done with the 
vibrating coil, the mechanical interrupter produces only one fat spark in 
each cylinder. 

This arrangement is not so complicated as the multiple coil system. 
There is only one adjustment, that at the contact maker, and this insures 
sparks of the same intensity in each of the cylinders. The drain on the 
batteries is also less, as only one spark is produced in each cylinder, in 
contrast to the series of sparks produced by a vibrating coil. 



102. The Connecticut Automatic Ignition System. This system 
operates on the high tension distributor principle, using but one coil for 
all cylinders. It employs a mechanical interrupter for the primary cur- 
rent. Although dry batteries can be used in cases of emergency, the 
system is primarily intended for the use of storage batteries as the source 
of current. Its ideal use is in conjunction with a generator supplying 
current to a storage battery for lighting and starting. Figures 148 and 
149 are wiring diagrams showing the connections for the Connecticut 

FIG. 149. Connecticut type G ignition system. 

types E and G systems. The essential difference between these systems 
is in the switch and coil connections. In type E the coil is integral 
with the switch and is designed to be placed under the hood, thus assist- 
ing in preserving a clean dash. Type G has a separate switch and coil, 
which permits its application where the space is limited, as for instance 
when the gasoline tank is carried in the cowl dash. The switch is 
mounted on the dash and the coil any place on the engine near the ig- 
niter, thus bringing the condenser close to the breaker points and elimi- 
nating the necessity of extending the high tension wires to the dash. 



The combined interrupter and high tension distributor is clearly 
shown in Figs. 150, 151, and 152. The interrupter, Fig. 150, first closes 
the circuit and permits battery current to flow through the primary 
circuit. When one of the lobes on the cam strikes the roller, the circuit 

FIG. 150. Connecticut interrupter. 

FIG. 151. Connecticut igniter with 
distributor cap removed. 

FIG. 152. Connecticut igniter 


FIG. 153. Connecticut type E coil and 
switch with cover removed to show 
terminal connections. 

is opened and a high voltage is thus produced in the secondary winding of 
the coil. The high tension current is distributed to the plugs by the 
distributor of the instrument. The distributor and interrupter are 



mounted in a single unit as shown in Fig. 152, the whole device being 
called the igniter. 

The igniter is mounted on a vertical shaft running at one-half engine 
speed and thus can be mounted the same as the ordinary timer for 
vibrating coils. Figure 153 shows the arrangement of the coil terminals. 
It will be noted that a spark gap is provided to protect the secondary 
winding from the destructive action of the high voltage in case a plug 
terminal becomes disconnected so that the high tension current can not 
take its regular path. The safety gap is placed in a glass tube inaccessible 
to vapor or fumes. It is conveniently arranged for observation in cases 
of missing cylinders. 

The spark advance and retard in the Connecticut system are effected 
by swinging the entire igniter housing either forward or back. 

103. The Atwater Kent System. The Atwater Kent system is also of 
the high tension distributor type and has as an optional feature the 


FIG. 154. Diagram showing principle of Atwater 
Kent system. 

FIG". 155. Exterior of 

automatic spark advance, which automatically regulates the position of 
the spark according to the speed of the engine. This system is designed 
to operate in a satisfactory manner with dry cells as the source of current. 
The Atwater Kent system consists of two main parts: 

(1) The unisparker, which is the contact maker and the distributor 
combined in one small case mounted on the timer shaft of the engine. 

(2) The coil, which consists of a simple primary and secondary 
winding with condenser. The coil has no vibrators or other moving 
parts, this function being served by the contact maker. The principle 
of the Atwater Kent system is clearly shown in Fig. 154. The battery 
current is closed and broken by the mechanical contact maker. The 
secondary current from the coil goes to the distributor, where it is 



directed to the proper plug. The distributor and contact maker are 
built together and are called the unisparker. 

The unisparker, Type K-2, is illustrated in Fig. 155. It is connected 
to the ordinary timer shaft of the engine, the dome-shaped cover con- 
taining the primary contact maker and the secondary distributor as 
well as the spark advancer. By releasing the two spring clips, the 

FIG. 156. Atwater Kent contact maker. 

rubber dome is lifted and the contact maker exposed. The contact maker 
of the unisparker is shown in Fig. 156. As will be seen from investigation, 
only one spark is produced per explosion stroke, as the circuit is made 
and broken but once. An important feature of this contact maker 
is that the length of contact is absolutely independent of the engine speed, 
and as strong a spark is produced when the engine is cranked by hand as 
when the latter runs at normal or even at racing speed. The length of 

FIG. 157. Operation of contact maker. 

contact is constant and no greater at any speed than is necessary to 
insure the magnetic field of the coil being built up to its full strength. 

The action of the contact maker is shown in Fig. 157. The hardened 
steel rotating shaft in the center, the lifter, the latch, and the contact 
spring are the principal moving parts. The contact is made and broken 
by the action of the lifter spring in drawing the lifter back, after it has 



become unhooked from the notched shaft. This spring action makes the 
speed of the break independent of the speed of the engine. It also makes 
the time of contact uniform, and this is adjusted so as to use the least 
possible current from the batteries. 

Directly above the contact maker 
is located the high tension distributor. 
This consists of a revolving hard rub- 
ber block driven by means of a key 
from the end of the operating shaft 
and carrying a contact segment on its 
circumference. Two, four or six con- 
tact pins, depending on the number of 
cylinders, are secured into the hard 
rubber cover plate of the device, which, 
as already stated, forms the body of 
the distributor. Proper cable connec- 
tions are formed on the terminals of 

the cover plate and, from these, connection is made to the individual 
spark plugs. 

The coil used in connection with the Atwater Kent system consists of 
simple primary and secondary windings of generous proportions, which, 

FIG. 158. Atwater Kent kick 
switch coil. 

Motor stopped or running slowly. Motor at high speed. 

FIG. 159. Atwater Kent automatic spark advance mechanism. 

together with a condenser, are sealed into a container. There are no 
moving parts or adjustments. 

One of three types of coils is usually furnished with the Atwater 
Kent system: a simple plate switch coil, a kick switch coil, shown in Fig. 
158, or an underhood coil with separate switch. Both plate and kick 




switches are provided with a push button for producing starting sparks 
without cranking. 

Automatic Spark Advance. -Figure 159 shows the centrifugal gov- 
ernor which advances the spark as the speed increases. The rotating 
shaft is divided, and as the governor weights expand they rotate the 
upper part of the shaft forward in its own direction of rotation, thus 
making and breaking contact earlier than at slow speed. 

In Fig. 160 the wiring diagram of the Atwater Kent installation is 
shown. Among the particular features of this system are: time of 
closed primary circuit is independent of engine speed; speed of break is 
independent of engine speed; circuit cannot be closed when engine is 
stopped; battery consumption is reduced to a minimum; the spark is 
uniform in all cylinders and is independent of engine speed. 

FIG. 160. Atwater Kent wiring diagram. 

104. The Westinghouse Ignition System. There are several igni- 
tion systems made, particularly for cars equipped for electric starting 
and lighting, in which the source of current is a storage battery kept 
charged at all times by the starting and lighting generator. In some, 
the generator simply keeps the battery charged and the ignition system 
is entirely separate but draws its current from the battery. In others, 
the generator carries the interrupter and the high tension distributor for 
the purpose of timing and distributing the current. 

The Westinghouse system of ignition is mounted as a unit with the 
electric generator which supplies electric current to the storage battery 
for lighting or starting or both. When the engine is not running or is 
operating at very low speed, the ignition current is supplied entirely by 
the battery. After the engine reaches a certain speed, the current may 
be supplied in whole or in part by the generator. 

The ignition outfit consists, in addition to the generator and storage 
battery, of an ignition switch and coil on the dash, and an interrupter 
and distributor which are made a part of the generator. The ignition 
coil transforms the voltage of the battery up to the high tension required 
for the spark plugs. The interrupter closes and then opens the ignition 
circuit at each half revolution of the generator shaft, and the distributor 



directs the high tension current to each of the spark plugs in succession. 
Figure 161 shows the exterior of the generator with the distributor and 
interrupter on the right hand end. 

FIG. 161. Westinghouse ignition and lighting generator. 

The view of the generator disassembled, Fig. 162, shows the principal 
parts. This system has an automatic spark advance operated by 
centrifugal weights inside the interrupter. 

FIG. 162. Parts of Westinghouse ignition and lighting generator. 

Figure 163 illustrates the interrupter with the centrifugal weights 
and springs in the position they occupy when the engine is at rest. 
Figure 164 shows the position that the weights occupy when the 
engine is running at high speed. 

The operation of the ignition system, including the interrupter and 


distributor, ignition coil and switch, begins with the "making" of the 
primary circuit of the coil when the centrifugal weights push down the 

FIG. 163. Westinghouse generator with distributor and interrupter cover removed. 

fiber bumper, forcing the interrupter contacts to close. Then the 
weight moves off the fiber bumper, allowing the contacts to suddenly 

separate or open. This break of the 

primary circuit induces a high voltage 
in the secondary of the ignition coil. 
This is led to the distributor, which di- 
rects it to the proper spark plug, caus- 
ing a spark at the spark plug gap. As 
the speed of the engine increases, the 
weights are thrown out from the center 
and automatically advance the time of 
closing or opening the interrupter con- 
FIG. 164. Westinghouse in- tacts, and hence advance the spark. At 

the Same time > due to their sha P 6 > ^ 
keep the contacts closed during a longer 
period of the revolution when running at high speed; this makes the 



length of time of contact practically the same at all speeds and prevents 
the spark voltage from falling off at high speeds. 

In generators not provided with automatic spark advance the cen- 
trifugal weights are omitted and a solid cam substituted. The interrupter 
contacts are changed so as to make the breaking of the contact occur 
when the lever is pushed down by the cam instead of when being 
returned by the spring. 

105. The Delco System of Ignition. All the Delco systems are not 
identical, there being slight changes to adapt them to the different cars. 
For example, the ignition coil on some cars is mounted on the dash, or 
on top of the starting motor-generator instead of on the side, as shown 
in Fig. 165. 

All current for lights, horn, and ignition is supplied first to the com- 
bination switch, and after passing through the protective circuit breaker 

FIG. 165. Delco ignition system. 

on the dash is distributed to these different units. When the generator 
is supplying the current, it comes from the forward terminal on the side 
of the generator through the wire A to the switch. The storage battery 
current is connected through the wire B. If the button B is pulled out, 
the current from the dry cells is used for ignition. If button M is pulled, 
the current will be taken either from the generator or storage battery, 
depending on whether or not the generator is in operation. Thus, either 
the M or B button may be used for starting. 

The excess current from the generator flows through the wire B to 
the storage battery. An ammeter inserted in the line A would indicate 
the amount of current coming from the storage battery to the generator 
when the engine is not running, or it would indicate the current being 
generated when the engine is running. 

Distributor and Timer. The distributor and timer is carried on the 


front of the motor-generator, and is driven through a set of spiral gears 
attached to the armature shaft. The distributor consists of a cap or 
head of insulating material, carrying one high tension contact in the 
center, with similar contacts spaced equidistant about the center, and 
a rotor which maintains constant communication with the central 
contact. The rotor carries a contact button which serves to close 
the secondary circuit to the spark plug in the proper cylinder. 

Beneath the distributor head and its rotor is the timer, a diagram 
of which is shown in Fig. 166. This is provided with a screw A in the 
center of the shaft, the loosening of which allows the cam to be turned in 
either direction to secure the proper timing, turning in a clockwise direc- 
tion to advance and counter-clockwise to retard. The spark occurs at 
the instant the timer contacts are opened. 

FIG. 166. The Delco timer. 

A weight on the timer shaft acts as a centrifugal governor to operate 
the automatic spark control. In addition to the automatic spark con- 
trol a manual control is provided, which is operated by a lever on the 
steering column, and is connected to the lever at the bottom of the motor 
generator. The manual spark control is for the purpose of securing the 
proper ignition control for variable conditions such as starting, differences 
in gasoline, and weather conditions. The automatic control is for the 
purpose of securing the proper ignition control necessary for the varia- 
tions due to speed alone. 

The Coil. The ignition coil is the dark vertical cylinder shown on the 
front side of the motor generator in Fig. 165. It serves to transform 
the low voltage current in the primary circuit to a current of high voltage 
in the secondary circuit. The coil consists of a primary winding of 
coarse wire wound around an iron core in comparatively few turns, and 
of a secondary winding of many turns of fine wire, also the necessary 
insulation and terminals for wiring connections. 



106. The Remy-Studebaker Ignition System. This system, shown 
in Fig. 167, is built by the Remy Electric Co. and is used on the Stude- 
baker car. It is of the high tension distributor type with the primary 
current furnished by the storage battery. Dry batteries are supplied for 
emergency purposes. The storage battery is kept charged by the starting 
generator. The distributor and breaker box form an individual unit, 
as shown in Figs. 168 and 169. Figure 169 shows clearly the operation 
of a distributor, the current entering at the center and being directed by 


FIG. 167. Wiring diagram of Remy-Studebaker ignition system. 

the revolving arm to the different contact plates on the inside of the cover. 
These connect to the different plugs. 

The transformer coil is of the non-vibrating type furnishing a single 
spark, the interruption of the primary circuit taking place in the breaker 
box. Inside the breaker box is the primary interrupter or circuit breaker. 
By the action of the cam D the two points A and B close and open twice 
in each revolution of the shaft. These points are in the circuit of the 
current flowing from the battery to the primary coil winding. The 
interruption of this current induces a high tension current in the secondary 
winding of the coil. The interrupter makes two sparks to one revolution 
of its shaft and therefore must run at twice the speed of the distributor 



FIG. 168. Face and side views of Remy-Studebaker distributor and breaker box. 



FIG. 169. Remy-Studebaker igniter disassembled. 



for a four-cylinder engine. For six cylinders it would make three revolu- 
tions to one of the distributor. 

107. Spark Advance and Retard. It is very essential in a variable 
speed gasoline engine that the time at which the spark occurs in the cylinder 
be changed according to the engine speed, as it takes a certain length of 
time to produce an explosion, regardless of the engine speed. When the 
engine speed is high, the spark must occur before the piston reaches dead 
center in order to have the full force of the explosion when the piston has 
just passed the center position. When the engine speed is slower, the 
spark can occur later and yet have the force of the explosion exerted 
just after dead center. It is necessary when starting that the spark occur 
not before dead center. 

These various considerations de- 
mand that the position of the spark 
be made variable. This is usually 
done by shifting the timer, or inter- 
rupter housing, causing the break of 
the primary current (and conse- 
quently the spark in the cylinder) 
to occur earlier or later. The posi- 
tion of the spark is in most cases 
governed from the steering column. 
In starting the engine, the spark 
should not occur until after the pis- 
ton has started on its down stroke. 
It should then be advanced as the 
engine increases its speed. If the 
spark is too far advanced there will 
be a decided knock in the cylinders. 

108. Automatic Spark Advance. In several modern ignition systems, 
means are provided by which the position of the spark is automatically 
advanced and retarded. This relieves the driver from the responsibility 
and uncertainty of correctly gauging the position at which to set the spark 
lever. Figure 170 shows the Delco spark advance mechanism used on 
the Cadillac. As is seen, it consists of a ring governor which determines 
just when the timer contact breaks. As the engine speeds up, the ring 
swings nearer to a horizontal position and this shifts the interrupter cam 
so that the circuit is broken earlier. A spring pulls them back when the 
engine slows down. The mechanism of the Atwater Kent automatic 
spark advance was shown in Fig. 159 and that of the Westinghouse system 
in Figs. 163 and 164. 

FIG. 170.- Delco automatic spark 
advance mechanism as used on Cadillac 


109. Principles of Magnetism. The principle upon which a magneto 
is constructed involves an understanding of some elementary magnetic 
and electrical principles in addition to those discussed in the preceding 

Magnets. It is a well known fact that either in a bar magnet or in a 
magnet bent in the shape of a horseshoe, as in Fig. 171 the "magnetism," 
that invisible force which attracts and repels iron or steel, is concentrated 
near the ends, as indicated by the bunches of iron filings at the ends of 
these magnets. One end of the magnet is called the "north" or N-pole, 

FIG. 171. 

and the other the "south" or S-pole. The difference between the two 
poles can be seen by taking two horseshoe magnets and placing their like 
poles and again their unlike poles together. It will be found that the 
"like" poles repel each other and the "unlike" poles attract each other, 
This is the fundamental law of magnetism. 

Lines of Force. If a horseshoe magnet be placed on its side, as shown 
in Fig. 172, a piece of paper put over it, and iron filings be sprinkled over 
the paper, we shall find that the filings arrange themselves in well- 
defined lines, their direction being as indicated. This arrangement 
shows us that there is a magnetic force acting between the two poles of 




the magnet. The direction is shown and, if the investigation be con- 
tinued, it will be discovered that this invisible force acts from north pole 
to south pole. These invisible lines are known as magnetic "lines of 

Permanent and Electro+magnets. Horseshoe magnets are either 
"permanent" or "electro" magnets. A permanent magnet is one 

FIG. 172. 

made of highly tempered steel which has been magnetized and usually 
retains its magnetism indefinitely. An electro-magnet, Fig. 173, is made 
of wrought iron or soft steel, and carries a coil of wire through which a 
current of electricity is passed when the iron or steel is to become mag- 
netized. As soon as the current in the wire is cut off, the magnet loses 
its magnetism. The name "electro-magnet" signifies that the mag- 

FIG. 173. Electro-magnet. FIG. 174. Simple magnet. Compound magnet. 

netism is the effect of the electric current. In the mechanical generation 
of current we shall see that the magnetism in the horseshoe magnet is 
made use of. If a permanent magnet is used for creating the magnetic 
field, the machine is called a "magneto" and if electro-magnets are 
used, the machine is called an electric generator. 




Simple and Compound Magnets. In some types of magnetos, com- 
pound permanent magnets are used. A compound magnet is one built 
up of several simple magnets, as shown in Fig. 174. It has been found 
that a compound magnet is much stronger than a simple magnet of the 
same size. 

110. Mechanical Generation of Current. It is found that if a wire 
be moved across the magnetic field be- 
tween the poles of a magnet so as to 
cut the "lines of force" there will be 
an electric current generated in the 
wire. If the wire should now be moved 
across the lines of force in the opposite 
direction, the current will also flow in 
the opposite direction in the wire. The 
reason for this is not clearly explained, 
but it is a well known fact that cutting 
magnetic lines of force by moving a 
wire across them will generate current 
in the wire. 

Pole pieces 

Rotating armature 

FIG. 175. 

This fact is made use of in the mag- 
neto, an elementary type of which is 
shown in Fig. 175. The wire has been formed in the shape of a rect- 
angle and arranged to rotate between the pole pieces of the magnet. 
If the ends of the wire are connected by a measuring instrument, a current 
of electricity will be found to flow out of one end of the wire and into 
the other end as the wire is revolved. This current will be an alternating 
current; that is, the current changes in direction each time the rectangle 

FIG. 176. 

turns over. When the wire is cutting the "lines of force" at right angles 
the voltage is the maximum, and it is at this period of rotation that the 
current is best for ignition purposes. This condition occurs twice during 
a complete revolution of the loop of wire. 

In an actual magneto, instead of having only one turn of wire, a 


great many turns of wire are wound in the shape of a coil around a piece 
of laminated iron, called the armature core. This coil is caused to rotate 
between the magnetic poles, generating a current in it. Figure 176 
illustrates the change and cutting of the magnetic lines of force during 
one complete revolution of the armature. By using the laminated 
iron armature core, the flow of the magnetism between the poles of the 
magnet is increased, thus increasing the lines of force that are cut by the 
coils of wire. 

111. Low and High Tension Magnetos. A "low tension" type of 
magneto is one which delivers current of a low voltage, which must be 
converted to the necessary high voltage for ignition by an external 
transformer coil. The armature contains only a primary winding, 
while the transformer coil has the usual primary and secondary windings. 

FIG. 177. Side view Remy Model P magneto. 

A "high tension" magneto delivers current from the armature of 
sufficiently high voltage for ignition, without the use of an external 
transformer coil. The high tension current is generated by having two 
windings on the armature of the magneto, one a primary winding, and 
the other a secondary winding. The armature assembly also contains a 
condenser. The true high tension magneto must not be confused with 
the so-called high tension magnetos in which the armature current 
is transformed by a coil merely placed in the top of the magneto, instead 
of outside as is done in the low tension type. The coil is merely con- 
tained in the magneto assembly for convenience but this does not make 
it a "high tension" magneto in the strict sense of the term. 

112. Armature and Inductor Types. : An "armature" type of 
magneto is one in which the lines of force are cut by means of a coil of 



wire wound on an armature rotating between the magnetic pole pieces, 
as just described. It may be either of the high or low tension type. 

In an "inductor" type of magneto, the coil of wire is stationary. 
The cutting of the lines of force by the stationary coil is caused by a 
revolving "inductor." The current is generated in the stationary coil 
and this avoids the necessity of having sliding contacts and brushes in 
order to connect the coil with the external circuit. The inductor type 
may also be "low" or "high" tension. The constructional features 
of these two general types will be pointed out in considering the several 
modern magneto types. 

FIG. 178. Distributor end view Remy Model P magneto. 

113. Remy Model P Magneto. Figures 177 and 178 show side 
and distributor end views of the Remy Model P magneto, of the low 
tension armature type. 

The Remy armature shown in Fig. 179 is of the H or shuttle type, 
with laminated core made from soft Norway iron. The armature heads 
are of hard bronze, and the drive shaft, which is of steel, is cast into the 
armature head. The armature winding is of cotton covered enameled 
wire heavily impregnated with a special insulating compound rendering 
it impervious to heat and moisture. The armature shaft revolves on 


magneto-type ball bearings which are made dust and grit proof by the 
use of felt washers. 

In a low tension magneto, the current generated in the armature is led 
through a circuit breaker to the primary winding of the coil. When the 
circuit breaker is closed, the current flows through the primary winding 
and magnetizes the core of the coil. At the desired instant for the 
spark, the circuit breaker opens the circuit quickly and thus destroys the 
magnetism of the core of the coil. This action induces a high tension 
current in the secondary winding of the coil. This is led back to the 
distributor of the magneto, where it is directed to the proper spark plug 
on the engine. 

The armature winding cuts the lines of force twice in each revolution 
and therefore will give two sparks per revolution. For this reason, there 
are two lobes on the cam which operates the circuit breaker. For a four- 
cylinder engine, the magneto armature should run at crank shaft speed, 
as two sparks are required per revolution of the engine. For a six- 
cylinder engine, the armature of the magneto should run at one and one- 
half times crank shaft speed, as three sparks are needed per revolution of 
the engine. The distributor" terminals should be connected to the plugs 
in the order in which the cylinders are to fire. 

The Circuit Breaker. The circuit breaker illustrated in Fig. 180 may 
be shifted by the spark lever to change the time of the spark. The 
breaker points are made of iridium-platinum, which gives them an 
exceedingly long life. The timing control lever may be located on either 
side of the magneto, as the circuit breaker and housing are reversible. 
An ample timing range of 35 is provided for. 

Condenser. The condenser, instead of being placed in the coil, is 
placed just above the armature. The purpose of the condenser is to 
prevent sparking at the breaker points, when they break the magneto 
primary circuit. 

Magnets. The magnets are made from tungsten-steel specially 
heat treated and hardened, thereby insuring the retention of magnetism 
for a long period. 

Coil. The coil, the top view of which is seen in the wiring diagram of 
Fig. 181, has the switch built integral with it. The coil is fastened 
behind the dash and the switch face only appears on the driving side. 

Distributor and Timing Button. The distributor terminals located on 
the face of the distributor provide a reliable method of securing the high 
tension spark plug cables. An ingenious device, known as the timing 
button, is incorporated in the distributor, for the purpose of timing the 
magneto to the motor. With this device the circuit breaker and dis- 
tributor are brought into proper position, thus facilitating this usually 
difficult operation of timing the magneto to the motor, an operation that 
frequently puzzles even an experienced repair man. 



FIG. 179. Armature of Remy Model P magneto. 

FIG. 180. Remy Model P magneto circuit breaker removed. 

FIG. 181. Wiring diagram for Remy Model P magneto. 


For timing the magneto, turn the engine over by the starting crank 
until No. 1 piston reaches the top dead center at the end of the com- 
pression stroke. Press in on the timing button at the top of the dis- 
tributor and turn the magneto shaft until the plunger of the timing 
button is felt to drop into the recess on the distributor gear. This places 
both distributor and circuit breaker in the proper position correspond- 
ing to the engine position given above, and they may now be coupled 

114. The Connecticut Magneto. This magneto, illustrated in Fig. 
182, likewise has a shuttle wound armature revolving between the 
poles of permanent magnets, and generates an alternating low ten- 
sion current with two impulses for each revolution. It has but a single 

FIG. 182. Connecticut magneto partially disassembled. 

primary wire running to the switch; all secondary wires connect from 
the magneto direct to the plugs. The transformer coil is encased in 
a metal tube in cartridge form and is mounted in the magneto just above 
the armature. 

115. Dual Ignition Systems. The voltage generated in a magneto 
depends on its speed, and this makes it desirable to have some other 
source of current for starting an engine. This auxiliary source is either 
a set of dry cells or a storage battery. In the dual system the battery 
supplies the primary current for starting, the current being led through 
the circuit breaker and primary winding of the coil. On the dual system 
the regular coil and distributor of the magneto are used. After the engine 
is started the switch can be thrown to use the magneto current. 



116. Eisemann High Tension Dual Ignition. The wiring diagram 
for the Eisemann E. M. Dual system is shown in Fig. 183. This magneto 
is of the high tension armature type. The Eisemann dual system consists 
of a direct high tension magneto and a combined transformer coil and 
switch, the transformer being used only in connection with the battery, 
and the switch being used in common by both battery and magneto systems. 
The magneto is practically the same as a single ignition high tension 
instrument. To insure reliability, the vulnerable parts of each system 
are separate from those of the other. For instance, separate windings 
and circuit breakers are used for each system. On the other hand, parts 

FIG. 183. Wiring diagram Eisemann type E. M. Dual four-cylinder ignition 


that are not subject to accident or rapid wear are used in common, so as 
to avoid unnecessary duplication. 

The magneto armature is an iron core, made of many pieces of soft 
sheet iron riveted together, around which is a primary winding of medium- 
gauge copper wire. Over this primary winding, is a secondary winding 
consisting of many coils of very fine copper wire, the wire being specially 
insulated in the entire length and the layers being carefully insulated 
from each other. The low tension current, formed by rotating the arma- 
ture, in turn induces a secondary or high tension current in the secondary 
winding. The transformation of the low tension current into high ten- 
sion current is obtained by suddenly interrupting the low tension current 



by the circuit breaker or make-and-break mechanism . It will thus be seen 
that the high tension armature is practically a transformer coil wound 
directly on the armature core with a circuit breaker to interrupt the 
primary current. 

Spark Control As the spark occurs when the primary circuit is 
broken by the opening of the platinum contacts, the timing of the spark 
can, therefore, be controlled by having these platinum contacts open 
sooner or later. This latter is accomplished by the angular movement of 
the timing lever body. This movement gives a timing range of 30. 
The spark is fully retarded when the timing lever is pushed as far as 
possible in the direction of rotation of the armature and is advanced 
when pushed in the opposite direction. 

Safety Spark Gap. If a spark plug cable becomes disconnected or 
broken, or should the gap in the spark plug be too great, then the second- 
ary current has no path open to it and, in endeavoring to find a circuit, 

FIG. 184. Eisemann armature with automatic spark advance mechanism. 

will sometimes puncture the insulation of the armature or of the coil. 
To obviate this, a so-called "safety spark gap" is placed on the top of 
the armature dust cover. It consists of projections of brass with a gap 
between. them. One of these is an integral part of the dust cover, and 
therefore forms a ground. 

The Coil. The coil of Fig. 183 is designated as Type D C and consists 
of a non-vibrating transformer and a switch which is used in common 
to put either the battery or magneto ignition into operation. The coil 
is cylindrical in shape, is compact, and is placed through the dashboard. 
The end which projects through on the same side as the motor has. 
terminal connections for the tables. The other end, facing the operator, 
contains the switch and the starting mechanism. The transformer coil 
is used only in conjunction with the battery. There is a push button 
circuit breaker in the center of the switch for producing a spark with 
the battery current when the engine is not running. The coil is provided 
with a lock and key, so that the switch may be locked in the "off" 


117. Eisemann Automatic Spark Control. The automatic spark 
control magneto is of the same construction as the standard high-tension 
instrument with the addition of the automatic mechanism as shown in 
Fig. 184. The automatic advance is accomplished by the action of 
centrifugal force on a pair of weights attached to one end of a spiral 
sleeve between the shaft of the magneto and the armature. When the 
armature is rotated, the weights begin to spread and exert a longitudinal 
pull on the sleeve, which in turn changes the position of the armature 
with reference to the pole pieces, In this way, the moment of greatest 
induction is advanced or retarded and with it the break in the primary 
circuit. The cams which lift the circuit breaker and cause the break in 
the primary circuit are fixed in the correct position with relation to the 
armature, so that the break occurs at the moment when the current in 
the winding is strongest. 

118. The K-W High Tension Magneto. The K-W high tension 
magneto is of the alternating current inductor type. Figure 185 is an 
external view and Fig. 186 shows a longitudinal sectional elevation. By 
referring to the numbers, an idea can be obtained of the function of the 
various parts. 

64 Driving pinion. 1 Bridge. 

79 Plunger for primary circuit. 100 High tension lead. 

67 Cam. 96 Distributor block. 

68 Cam roller. 73 Magnets. 
189 Retainer spring. 180 Rotor. 

56 Switch binding post. 114 Primary winding. 

98 Distributor brush holder. 113 Secondary winding. 

120 Secondary contact plunger. 126 Condenser. 

119 Secondary distributor 118 Safety spark gap. 

plunger. 186 High tension bus bar. 
2 Distributor gear. 14 Low tension bus bar. 

10 Base. 

The only revolving part in the K-W magneto is shown in Fig. 187. 
This part is the rotor which is constructed of fine laminations of the 
softest Norway sheet iron. These laminations are riveted together, 
are accurately bored out to fit the rotor shaft, and are accurately ma- 
chined as to width and diameter, being mounted on this shaft at exactly 
right angles to each other. Between these two pieces is the stationary 
winding or coils, also shown separately in Fig. 188. The winding, which 
is concentric with the armature shaft, is mounted in between the two 
halves of the rotor and stands absolutely still. In the position shown, 
the lines of force go straight across through the right hand rotor. When 
the shaft turns 45 from this position, the rotors connect the magnetism 
from one pole piece, through the center of the winding, to the opposite 
pole piece, thus giving a powerful wave of current from a quarter revolu- 
tion of the magneto. 


The winding, shown in Fig. 188, is a double winding, that is, it has a 
primary or low tension winding, which is surrounded by a secondary or 
high tension winding. This primary winding goes to the circuit breaker 
of the magneto, where its current is interrupted when the spark is 

FIG. 185. K-W high tension magneto. 

FIG. 186. Section of K-W magneto. 

wanted and during one of the periods of armature rotation in which con- 
siderable current is generated. 

At the moment of this interruption of current in the primary, a power- 
ful surge of current is generated in the secondary winding. The current 
from this secondary winding goes straight up through the hard rubber 
terminal to the high tension bus bar, as shown in Fig. 186, to the center 



of the distributing brush* and from there is distributed to the various 
cylinders of the motor. 

The condenser, No. 126, Fig. 186, is bridged across the circuit breaker 
points. Its function is to absorb the low tension current after the 

FIG. 187. K-W rotor and coils 

FIG. 189. Wiring diagram for K-W high tension magneto. 

breaking of the primary circuit at the breaker points. This condenser 
is made of a large number of sheets of tinfoil and mica. 



The safety gap, No. 118, Fig. 186, is a necessary part of any high tension 
magneto, its object being to form a path for the high tension current to 
jump through incase a secondary cable that leads to the spark plugs 
should be off when the engine is running. This safety gap, as its name 
implies, prevents the magneto from burning out, for as long as there is a 
path for the high tension current to pass through, it will never punc- 
ture the insulation of the secondary winding. 

It will be noted by referring to Fig. 186 that the distributor shaft is 
carried on two ball bearings, as is also the rotor shaft. The distributor 
block is moulded from a special composition of hard rubber, and is ac- 
curately machined all over. The brass segments that connect with the 
various plug holes on top of the distributor are moulded into the hard 

FIG. 190. Dixie magnets and rotor. FIG. 191. Dixie coil and field pieces. 

rubber. A carbon brush is mounted in the distributor arm, which presses 
slightly against the distributor segments, and the interior of the distributor 
is practically dust and moisture proof, being protected by a hard rubber 
cover, held in place by a three-legged spider or bridge, No. 1 . This bridge 
also carries the primary circuit to the circuit breaker. The binding 
post, No. 56, is the point from which the switch wire is run to the switch 
for the purpose of cutting out the circuit breaker and stopping the engine. 

Figure 189 is a wiring diagram for the K-W high tension magneto, 
Type H. 

119. The Dixie Magneto. The Dixie magneto is built upon a princi- 
ple different from that of either the armature or the inductor types. 
Figure 190 indicates the arrangement of the magnets and the rotating 
element carried in bearings by the two pole pieces. This rotor turns 



between the pole pieces and, as the iron pieces simply form extensions 
to the magnet pole pieces and are always of the same polarity, there is 
no reversal of magnetism through them. 

Just above the rotor, and with its axis at right angles, is placed the 
coil, supported by the two upright field pieces enclosing the armature as 
shown in Fig. 191. Figures 192, 193, 194, and 195 show the reversal of the 

FIG. 192. FIG. 193. FIG. 194. FIG. 195. 

FIGS. 192 TO 195. Showing the principle of the Dixie magneto. 

lines of force through the coil during one-half revolution of the rotor. 
This change of the lines of force through the coil, which has a primary and 
a secondary winding, causes a low tension alternating current in the 
primary winding, and this induces the high tension current in the secondary 
winding when the contact points break the primary circuit. Figure 196 
is a diagrammatic sketch of the primary circuit. P is the primary coil, A 

FIG. 196. Primary circuit of Dixie magneto. 

FIG. 197. Bosch high tension 

is the core, R is the condenser, X and Y are the circuit breaker points, G 
is the common ground connection for both primary and secondary wind- 
ings, and S is the secondary coil. 

120. The Bosch High Tension Magneto. The Bosch magneto, 
shown in Fig. 197, is of the high tension armature type, generating two 
sparks during each revolution of the armature shaft. A longitudinal 


section of a Bosch magneto is shown in Fig. 198 and a rear view in Fig. 
199. The principal numbered parts are as follows: 

1 Brass plate at the end of the primary winding. 

2 Fastening screw for contact breaker. 

119 Long platinum contact screw. 
118 Short platinum contact screw. 

9 Condenser. 

120 Lock nut for contact screw 119. 

121 Flat spring for magneto interrupter lever. 
105 Holding spring for interrupter cover. 

10 High tension collector ring. 

11 Carbon brush for high tension current. 

12 Holder for brush. 

13 Fastening nut for brush holder. 

FIG. 198. Section of Bosch high tension magneto. 

14 Spring contact for conducting the high tension current. 

15 Distributor brush holder. 

16 Distributor carbon brush. 

17 Distributor disc. 

18 Central distributor segment. 
20 High tension terminals. 

22 Dust cover. . 
123 Interrupter lever. 

168 Interrupter housing and timing lever. 

169 Cover for interrupter housing. 
173. Low tension brush. 

The beginning of the primary winding is grounded to the armature 
core and the other end is connected to the brass plate 1. In the center 
of this plate is the fastening screw 2, which serves first, for holding the 
contact breaker in its place, and second, for conducting the primary cur- 
rent to the platinum screw block of the contact breaker. Screw 2 is insu- 



lated from the contact breaker disc, which is in metallic connection with the 
armature core. The platinum screw 119 is fixed in the contact piece 
and receives the current from screw 2. Pressed against this platinum 
screw, by means of the spring shown, is the magneto interrupter lever 123 
with platinum screw 118, which is connected to the armature core and, 
therefore, with the grounded end of the primary winding. The primary 
circuit is, therefore, closed as long as the magneto interrupter lever 123 
is in contact with platinum screw 119. The circuit is interrupted when 
the lever is rocked by the cam so as to open the contact. The condenser 
9 is connected across the gap formed when the contacts break. 

The beginning of the secondary winding is connected to the insulated 
end of the primary so that the one forms a continuation of the other. 
The other end of the secondary winding leads to the collector ring 10, 



FIG. 199. End view of Bosch high tension magneto. 

on which slides a carbon brush 11, held by the carbon holder 12, and thus 
insulated from the magneto frame. From the brush 11 the secondary 
current is conducted to the terminal 13, through the spring connection 
14 to the center distributor contact 18, and from there to the carbon 
brush 16, the latter rotating with the distributor gear wheel. 

In the distributor disc 17, metal segments are embedded, and as the 
carbon brush 16 rotates, it makes contact with the respective segments of 
the distributor. Attached to the metal segments of the distributor are 
the connection terminals 20 to which are fixed the conducting cables to the 
spark plugs. 

From the end of the secondary winding the high tension current is 
distributed to the respective cylinders in the order in which they operate. 
The current produces the spark which causes the explosion; it then 
returns through the motor frame and the armature core back to the be- 




ginning of the secondary winding. The diagram of connections is shown 
in Fig. 200. 

Safety Spark Gap. In order to protect the insulation of the armature 
and of the current conducting parts of the apparatus against excessive 
voltage, a safety spark gap is provided as shown in Fig. 200. The current 
will pass through this gap in case a cable is taken off while the magneto 
is in operation or if the electrodes on the spark plugs are too far apart. 
The discharges, however, should not be allowed to pass through the 
safety gap for any length of time; special care has to be taken in this 
respect if the motor is equipped with a second system of ignition, in 


FIG. 200. Wiring diagram of Bosch high tension magneto. 

which case it is necessary to short circuit the primary winding, as the 
continued discharge of the current over the safety gap is likely to damage 
the magneto. 

121. The Bosch Dual System. In the Bosch dual ignition system, 
the standard type of Bosch magneto is used with the application of two 
timers or interrupters. The parts of the regular current interrupter are 
carried on a disc that is attached to the armature and revolves with it, 
the rollers or segments that serve as cams being supported on the inter- 
rupter housing. In addition, the magneto is provided with a steel cam 
which is built into the interrupter disc and has two projections. This 
cam acts on a lever supported by the interrupter housing, the lever 
3emg so connected in the battery circuit that it serves as a timer to 
control the flow of battery current. These parts may be seen in Fig. 




FIG. 201. Bosch dual system, showing magneto interrupter and battery timer. 

FIG. 202. Wiring diagram for Bosch dual system. 


201. A non-vibrating transformer coil is used with the battery current 
to produce the necessary voltage. 

It is obvious that the sparking current from the battery and from 
the magneto can not be led to the spark plugs at the same time, so a 
further change from the magneto of the independent form is found in 
the removal of the direct connection between the collecting ring and 
the distributor. The collecting ring brush shown in Fig. 198 as No. 11 
and in Fig. 202 as No. 3, is instead, connected to the switch, and a second 
wire leads from the switch to the central terminal on the distributor. 
When running on the magneto, the sparking current that is induced in 
the secondary armature winding flows to the distributor by way of the 
switch contacts. When running on the battery, the primary circuit of 
the magneto is grounded, and there is, therefore, no production of spark- 
ing current by the magneto; it is then the sparking current from the 

Fio. 203. Parts of Bosch dual coil. 

coil that flows to the central distributor connection. It will thus be 
seen that of the magneto and battery circuits the only parts used in 
common are the distributor and the spark plugs. 

The Bosch Dual Coil. The Bosch dual coil used in the dual system 
consists of a cylindrical housing bearing a brass casting, the flange of 
which serves to attach the coil to a dashboard or other part. The coil 
is provided with a key and lock, by which the switch may be locked when 
in the " Off" position. This is a point of great advantage, for it makes it 
unlikely that the switch will be left thrown to the battery position when 
the engine is brought to a stop. The absence of such an attachment is 
responsible in a large measure for the accidental running down of the 
battery. This locking device also prevents the unauthorized operation 
of the engine. The parts of the coil are shown in Fig. 203. In addition 


to the housing and end plate, they consist of the coil itself, the stationary 
switch plate, and the connection protector. 

When the engine is running on battery ignition, a single contact 
spark is secured at the instant when the battery interrupter breaks 
its circuit, and the intensity of this spark permits efficient operation of 
the engine on the battery system. 

Starting on the Spark. For the purpose of starting on the spark, a 
vibrator may be cut into the coil circuit by turning the button that is 
seen on the coil body in Figs. 202 and 203. Normally, this vibrator 
is out of circuit, but the turning of the button places it in the battery 
primary circuit instead of the circuit breaker on the magneto. A 
vibrator spark of high frequency is thus produced. 

It will be found that the distributor on the magneto is then in such 
a position that this vibrator spark is produced at the spark plug of the 
cylinder that is performing the power stroke; if mixture is present in 
this cylinder, ignition will result and the engine will start. 

Connections. In the wiring diagram of this system as shown in Fig. 
202, it will be noted that while the independent magneto requires but one 
switch wire in addition to the cables between the distributor and spark 
plugs, the dual system requires four connections between the magneto 
and the switch; two of these are high tension and consist of wire No. 3 
by which the high tension current from the magneto is led to the switch 
contact, and wire No. 4 by which the high tension current from either 
magneto or coil goes to the distributor. Wire No. 1 is low tension, 
and conducts the battery current from the primary winding of the coil 
to the battery interrupter. Low tension wire No. 2 is the grounding 
wire by which the primary circuit of the magneto is grounded when the 
switch is thrown to the off or to the battery position. Wire No. 5 leads 
from the negative terminal of the battery to the coil, and the positive 
terminal of the battery is grounded by wire No. 7; a second ground wire 
No. 6 is connected to the coil terminal. 

122. Bosch Two -independent System. The Bosch two-independent 
or double system consists of two complete and independent systems of 
ignition. One consists of a Bosch high tension magneto system and the 
other of a Bosch high tension distributor battery system. 

The battery system is utilized for starting purposes and for emergency 
ignition in case of accident to the magneto system, which is used for 
ordinary service. The battery system consists of a combined coil and 
switch and a timer-distributor, which are completely independent of the 
magneto. The two systems are brought together at the switch, and the 
connections are such that the engine may be operated on the magneto 
with one set of plugs, or on the battery with the other set of plugs, 
or on the magneto and battery together, in which case both sets of 



plugs are used. Either the battery or magneto may be used for ignition 
with the other system entirely dismantled or removed from the engine. 
The wiring diagram for this system is shown in Fig. 204. 

123. The Ford Magneto and Ignition System. The magneto which 
generates the current for the ignition system in the Ford car is of the low 
tension alternating current type and differs from the conventional type 
in that the stationary and revolving elements are interchanged. 

The Ford magneto, as shown in Fig. 205, has but two parts, a sta- 
tionary armature, consisting of a number of coils, which are attached 
to a stationary support in the flywheel housing, and a set of permanent 
field magnets of the horseshoe type, which are secured to the flywheel, 
the whole being a part of the motor. The magnets revolve with the 
flywheel at a distance of ^2 m - from the coils, in which the current is 

FIG. 204. Wiring diagram for Bosch two-independent system. 

induced by the magnetic field. The current flows to the four spark coils, 
passing through whichever one is at the instant connected to the ground 
by the commutator. The coils are the ordinary double winding vibra- 
tor coils. ^ The induced current from each coil goes to its spark plug to 
perform its function of igniting the charge. The magneto and its 
component parts are fully illustrated in Fig. 206. 

The diagram of Fig. 207 shows the plan of wiring of the Ford Model 
T motor, which, it will be noted, is very simple. The current generated 
by the magneto flows through the primary winding of the coil whose 
circuit is closed by the commutator, to the commutator, and back through 
the frame of the motor to the magneto. This completes the primary 



circuit or path of the magneto current. The high tension induced in 
the secondary winding of the coils is led to the spark plugs in the cylinders 
as their respective primary circuits are completed by the commutator. 

Magneto Coil Spoof 

Copper Wire 

End of Ribbon 1 
Grounded Here J 

To Coil 

Magneto Coil Support 

FIG. 205. The Ford magneto. 

124. Magneto Speeds. Nearly all of the modern magnetos are con- 
structed, as was pointed out in Art. 113, page 157, to give one spark for 
each one-half revolution of the armature or inductor. This means that 

FIG. 206. Diagram showing the course of circuit through the Ford ignition circuit. 

for each revolution, two sparks are obtained from the magneto. For a 
four-cylinder four-stroke engine, there are two explosions per revolution 
of the crank shaft. We see, therefore, that the magneto and engine 



crank shaft must run at the same speed. For a six-cylinder four-stroke 
engine, there are three explosions per revolution of the crank shaft, re- 
quiring one and one-half revolutions of the magneto. The magneto 
must, therefore, run one and one-half times the crank shaft speed. Some 
magnetos are built to give four sparks per revolution. These must, of 
course, be set to run at one-half the speeds given above. 

125. Timing the Magneto. Necessarily, the rules for setting and 
timing magnetos must be very general. If the magneto has been removed 
or is out of adjustment, the engine should be cranked until the No. 1 
piston (the one next the radiator) is on dead center at the end of the 
compression stroke. This position can usually be found by markings on 
the flywheel. On some engines the manufacturers recommend that the 
engine be cranked just a few degrees past the dead center. The position 
will then be the firing position for the No. 1 cylinder. 

Contact Terminal 

Commutator Wires 
and Loom. 

FIG. 207. Wiring of the Ford ignition system. 

The distributor housing should then be taken off and access gained 
to the distributor mechanism. It should also be determined just which 
cylinder corresponds to each of the distributor points. The armature 
should then be rotated until the distributor segment comes in contact 
with the distributor point for No. 1 cylinder. Adjust the armature so 
that the contact points just break when the interrupter housing is in full 
retard and attach it to the driving shaft. The spark control rod should 
now be connected and adjusted so that the contact points just open, when 
the spark lever on the steering wheel is in full retard. This permits the 
maximum spark advance. 


126. Battery vs. Magneto Ignition. It is a somewhat common idea 
that an engine will run faster on a magneto spark than on a battery spark. 
This contention has been frequently advanced in support of magneto 
ignition. Extensive experiments on engines equipped with a double 
system, one a magneto and the other a battery system, prove that with the 
same spark setting, there is practically no variation in engine speed, 
provided both systems are in perfect order and adjustment. In in- 
dividual cases where the contrary has been found it was probably due to 
some weakness or defect in the system which was replaced and should 
not be taken as condemning that type of ignition in general. 

127. General Suggestions on Magnetos. The magneto should never 
be tested unless the whole system is completely assembled with all parts 
and wires in place and attached. Water should be kept away from all 
parts of the ignition system. Magnetos were not intended to be run in 

Care should be taken when oiling parts of the magneto. A small 
amount of oil properly placed is essential, but a great lot on everything 
is a constant source of trouble. 

Don't take the magneto apart or try to improve its construction. 
Repairing a magneto is an expert's work. Unless you are one, don't 
attempt it. 

128. Common Magneto Ignition Definitions. Low Tension Magneto. 
A magneto which generates a low voltage current, requiring a trans- 
former coil to raise the voltage for ignition purposes. Only one wind- 
ing is found on the armature. 

High Tension Magneto. One which generates current of high enough 
voltage for ignition purposes. The armature contains two windings, 
a primary and a secondary winding. No outside coil is necessary. 

Armature Type Magneto. One in which the current is generated by 
a coil of wire wound around a core revolving between the poles of a 
permanent magnet. 

Inductor Type Magneto. A type of magneto in which the coil is 
stationary and the lines of force through the coil are changed in direction 
by means of a rotating inductor. 

Dual System of Ignition. A system of ignition with two sources of 
current, magneto and battery, either of which may be used. There is 
practically no duplication of equipment, as the magneto timer, distributor 
and plugs are used for both sources of current. 

Double System of Ignition. Two complete systems of ignition with 
nothing in common excepting the switch on the dashboard. There 
is a duplication of practically the entire equipment, plugs, timer, and 


129. Starting on the Spark. If an engine is stopped with an explosive 
mixture in the cylinder, it may sometimes be started from rest by merely 
causing a spark in the cylinder. In a four-stroke engine having four or 
more cylinders there will always be one cylinder on the expansion stroke 
and one on the compression stroke. On a four-cylinder automobile 
we can sometimes swing the spark lever so as to cause a spark in one of 
these cylinders, and, if the compression has not been lost entirely, or the 
gasoline vapor has not been condensed, the engine will start. Sometimes 
an engine can be started in this manner after standing for several hours. 
To make an engine more sure of starting on the spark, the throttle 
should be opened wide before the engine is stopped. This will insure a 
good charge in each cylinder. When a four-cylinder motor comes to 
rest after the spark is shut off, one piston will be on its exhaust stroke and 
another will be on its suction stroke, both of these cylinders, therefore, 
being open to the air. A third piston will be on its compression stroke 
with all valves shut and the fourth will be going down on the expansion 
stroke with its charge still fresh because the current has been turned off. 
The motor will come to rest with these two pistons on the same level, 
each about halfway in the stroke. To start the motor, turn the switch 
to the battery side and press the ignition starter button. Pressing the 
ignition starter button short-circuits or cuts out the timer or circuit 
breaker and causes current to flow through the primary winding of the 
coil. Releasing the push button breaks the primary circuit and causes a 
high tension current in the secondary circuit, which will be conducted 
to a spark plug provided the distributor arm is opposite one of the 
distributor segments. 

If the engine comes to rest with the piston which is on the working 
stroke on the same level with the piston which is on the compression 
stroke, the distributor arm will be nearer to the segment leading to the 
cylinder whose piston is on the working stroke. If the spark occurs in 
this cylinder the engine will be run in the desired direction and if the 
explosion is sufficient to carry the next piston over the top of the com- 
pression stroke, the regular cycles will be continued; but if, when the 
engine stops, the pistons have gone beyond the position where they are 
on the same level, the spark is apt to occur in the cylinder which is on 



the compression stroke. This explosion will drive the engine backward. 
l^>ar the end of this backward stroke the inlet valve will open and the 
burnt gases will be discharged through the carburetor. 

If the engine is stopped so that the timer points or circuit breaker 
points are in contact, it is impossible to start by pressing the ignition 
starter button, but starting may be accomplished by retarding the spark 
control lever and opening and closing the ignition switch, several times if 

The same method of starting will apply to two- or three-cylinder, 
two-stroke engines. If a two-stroke engine is started by advancing the 
spark, the motor will continue to run, but in the opposite direction from 
that desired. A common way of starting a single-cylinder two-stroke 
engine is to retard the spark and then turn the engine backward by hand 
until the spark occurs. The engine will then be propelled in the desired 

The failure of engines to start on the spark after standing for some 
time is largely due to the gasoline vapor being heavier than air. After 
an engine has stood for some time the heavy vapor will settle, and, if 
the engine is cold, the gasoline may condense on the piston and cylinder 

130. Mechanical Starters. Self starters may be divided into four 
general types: mechanical starters, air starters, acetylene starters, and 
electric starters. 

Mechanical starters include the various types of hand cranking 
devices and springs. The disadvantage of the hand cranking starter is 
that it requires a certain amount of human power. The only advantage 
is that the driver does not have to leave his seat to crank the engine. 
The spring starter is capable of giving the engine a few revolutions only, 
and if the engine does not start then, it becomes necessary for the driver 
to wind up the spring, which is a rather tiresome operation. If the 
motor starts, there is an automatic device by which the spring is wound 
up by the engine. 

131. Air Starters. In the air starters, the air is pumped into a storage 
tank at about 150 Ib. pressure. The engine is started by admitting 
air into the combustion chamber. The pipe leading from the tank goes 
to a distributor which is driven by the motor. In this way the air gets 
only to the cylinder which is on the working stroke and has all the valves 
closed. This system has the disadvantage that the air is liable to cool 
the cylinder and prevent proper starting of the regular cycle on account 
of the gas condensing on the cool walls. 

132. Acetylene Starters. Some manufacturers have equipped their 
machines with a device for starting with acetylene gas. This gas is 
very explosive and will ignite readily under almost any conditions. 


These engines are equipped with valves and tubes from the acetylene 
lighting system so that the driver can inject a small quantity of acetylene 
gas into the cylinders. The engine will then be practically sure of start- 
ing on the spark. This system has been largely superseded by the 
electric starter. 

133. Electric Starters. A still further development in this line is the 
electric starter. Electric starters may be divided into three types: 
first, the single-unit system; second, the two-unit system; and third, the 
three-unit system. In the first system the motor-generator unit furnishes 
the current to charge the storage battery and operate the lights, and 
also acts as a motor in cranking the engine. The two-unit system 
has a generator for charging the battery and furnishing the current for 
lighting and ignition, but it has a separate unit (a direct current motor) 
for cranking the engine. The three-unit system has a generator used 
solely for charging the battery and operating the lights, a motor for 
cranking the engine and a magneto for furnishing current for ignition. 

In all electric self-starters it is necessary to have a storage battery to 
store up the current so that there is a ready source of sufficient current to 
drive the motor for starting. The units of the self-starting system are: 
the generator to furnish electricity; the storage battery which acts as a 
reservoir to hold the supply of current ; and an electric motor to crank the 
engine. The electric starter may be directly connected to the gas engine, 
or it may be driven by a set of gears, or by a silent chain. 

In order that the electric motor will not be overspeeded when the 
engine picks up, it is necessary to have an overrunning clutch. This 
device operates only when the engine runs faster than the motor. The 
reduction in gears between the electric motor and the engine is about 25 
to 1, which means that the electric motor must run twenty-five times as fast 
as the engine. If it were not for the over-running clutch, the electric motor 
would be driven at excessively high speed, when the engine picks up 
to, say, two or three hundred revolutions per minute. The over-running 
clutch is automatic. It permits the electric motor to drive the engine, but 
breaks the driving connection as soon as the engine speeds up to a 
higher rate than the motor is running at. In the one-unit and two-unit 
systems, the current for ignition is taken from the storage battery. In 
all cases the current for the lights comes from the battery when the 
engine is running at low speeds. 

There is also another type of self starter which takes the place of 
the engine flywheel. This unit is a motor-generator outfit and has no 
reduction gear whatever. 

134. Storage Batteries. A commercial storage cell, as shown in Fig. 
208, is made up of the following parts: a jar or container usually made 
of rubber, positive and negative plates, separators between the plates, and 



the electrolyte. The electrolyte is a solution of sulphuric acid and 
water. After the plates are prepared, they are placed in the container 
and the electrolyte added. The current is then passed through the 
plates and solution. In this manner the battery is charged. When 
the battery is fully charged, the electrolyte or solution in the cells should 
have a specific gravity of 1.27 to 1.29. The specific gravity will become 
lower as the battery discharges and, when completely discharged, should 
not be lower than 1.15 to 1.17, or about twelve points less than when fully 
charged. Water must be added occasionally to replace the loss by 
evaporation. If one cell regularly requires more water than the others, 
it is an indication of a leaky jar. A leaky jar should be immediately 
replaced by a new one. The specific gravity of the electrolyte is the 



Mud Spaces 

FIG. 208. Section of storage cell. 

most reliable indication of the state of charge of the battery. It should 
never go below 1.15, for below that the battery will not have sufficient 
power to turn over the engine and it will not burn the lights so as to 
give the full candle power. The electrolyte must always cover the plates. 
The loss by evaporation should be replaced by adding pure fresh water. 
The water for filling the batteries must be either distilled water, melted 
artificial ice, or fresh rain water. Never add acid. The batteries should 
be inspected once every 2 weeks and, if the electrolyte is below the 
bottom of the filling tubes, water enough should be added to bring the 
level up to the proper point. Ordinarily it will require only a few spoon- 
fuls. The filling plugs must be replaced and screwed up tight after 
filling. Never keep the supply of water in a metal container, a bucket or 


can. It is best to get a bottle or jug of distilled water from your druggist 
or from the ice plant. The main point is to keep metal particles out of 
the battery. Spring water, well water, or hydrant water from iron pipes 
will contain iron and other materials in solution which will cause trouble 
by short circuiting the plates. 

If the electrolyte has been spilled from a cell, replace the loss with 
new electrolyte and follow with an overcharge, either by running the 
engine for several hours, or by charging from an outside source. In 
replacing electrolyte, have the specific gravity the same as in one of the 
adjacent cells. This can be determined by use of the hydrometer. 
When new electrolyte is required, either to replace loss from spilling, or 
when removing the sediment, or to replace a broken jar, it can be made 
by mixing chemically pure sulphuric acid, having a specific gravity of 
1.84, and distilled water in the proportions of 1 part of acid to 3 parts of 
water, by volume. The acid should always be poured into the water, and 
not the water into the acid. A glass, or other acid-proof vessel, thor- 
oughly cleaned, should be used for mixing the electrolyte. When 
replacing the cell, be sure that the positive and negative connections 
have the same positions as before. Then apply vaseline or grease to the 
studs and nuts before making the connections. 

After standing for some time, sediment will accumulate in the bottom 
of the jar. This should always be removed before it reaches the bottom 
of the plates. It can be determined by inspection, and will be indicated 
by lack of capacity, excessive evaporation and overheating when 
charging. If the battery needs repairing, it is best to communicate with 
the manufacturers who will advise you what to do. The battery is the 
heart or center of the system. The electricity generated by the dynamo 
is stored in the battery, and is used by the starting motor to crank the 
engine, and for the lights at low speed and when the engine is at rest. 
When the current flows from the dynamo through the battery elements, 
it is termed charging, and when the battery is supplying current for crank- 
ing the engine or to the lights, it is termed discharging. 

Immediately upon receipt of a battery or new automobile, the battery 
should be inspected. Remove the vent plugs. See that the battery 
plates are well covered with solution, and if it is not up to the inside cover 
(see Fig. 208) add distilled water. Filling one cell does not fill all the 
cells. The battery, if neglected, will cause the entire system to fail. The 
starting motor may operate when the battery is weak, but the battery 
life is thereby shortened. If, however, the battery is kept fully charged, 
and properly supplied with pure water, it will give uninterrupted service. 
The majority of car owners are careless about giving the battery the 
attention it should have. Remember that if the plates are exposed (not 



covered by battery solution) they become sulphated and hard, and the 

battery capacity is greatly reduced. 

Specific gravity tests are made with the hydrometer. When the 

battery does not give the desired results, specific gravity tests of each cell 
will indicate the faulty cell or cells. Figure 209 shows the 
ordinary type of hydrometer syringe used in determining 
the specific gravities of solutions. 

The action of this hydrometer is similar to that shown 
in Fig. 95, but it is contained in a syringe by which a 
sample of electrolyte may be drawn from the cell. To use 
the hydrometer expel the air from bulb by pressing it. 
Then insert the nozzle into the battery opening and allow 
the depressed bulb to draw sufficient electrolyte into the 
syringe to float the hydrometer. The specific gravity or 
density of the electrolyte is then indicated by the number 
on the hydrometer stem at the surface of the electrolyte. 
Always return the battery solution to the cell from which 
it was taken. 

Take the hydrometer readings just previous to adding 
water. If the hydrometer readings show that one cell is 
discharged, or nearly so, while the other cells are charged, 
it indicates that the cell is defective. This may be due to: 
1. Short circuits in that particular cell, thus discharg- 

. , in g it- 

I 2. Sulphating of the plates, caused by infrequent filling 

with water or by allowing to stand discharged. 

3. Leak in the cell, thereby requiring more water than 
other cells, which reduces the gravity. 

Freezing of the electrolyte is avoided by keeping the 
battery fully charged. As the specific gravity of the elec- 
o* 209 trolyte decreases (result of discharging) , freezing will occur 
Hydrome- at temperatures as follows: 
ter syringe. 


Specific gravity 
1 . 120 or lower. 

While it is possible to freeze a fully charged battery, it can be done only by 
very low artificial temperatures. 

If battery is allowed to remain discharged or if plates are not well 
.covered, the elements become sulphated, and the capacity is thereby 

Condition of charge 

Fully charged. 
34 discharged. 
3^3 discharged. 
% discharged. 

Freezing point 

Can not freeze. 
50 below zero. 
20 below zero. 
20-30 above zero. 



Line (UP Volts direct Current) 

3-15 Ann 


reduced. Sulphate can sometimes be removed by a prolonged low 
charging rate, but more frequently the battery is beyond redemption. 
The plates should always be well covered and needless discharge 

If the starting motor is used unnecessarily for cranking the engine or 
for propelling the car, rapid discharge takes place. Avoid this whenever 
possible, as under this condition the 
dynamo must be operated a long 
time to replace in the battery the 
amount of current taken by the start- 
ing motor. 

If the battery is neglected the 
center and upper portions of plates 
become sulphated. This condition is 
not due to any fault of battery ma- 
terial or construction nor to the start- 
ing-lighting units, but is directly at- 
tributable to inattention and neglect 
on the part of the car owner who has 
failed to add sufficient distilled water 
to the solution in each cell, in order to 
keep the plates properly submerged. 
Be sure to add distilled water to the 
battery every week or two. 

135. Battery Charging. Figure 
210 shows how lamps are connected 
in a direct current circuit for battery 
charging. Connect a wire A from 
one side of lighting source to one side 
of these lamps, and to other side 
connect another wire B. Then con- 
nect wire C to the other side of light- 
ing source. When the other end of 
this third wire C is connected to the 
end of wire B, the lamps should light. 
Now determine which is the. positive 
(+) and which is the negative ( ) wire. Disconnect these two wires C 
and B which caused lamps to light, and dip the ends in a bowl of water 
containing a few tablespoonfuls of salt or one tablespoonful of battery 
solution. Hold the immersed ends about 34 i n - apart. The wire from 
which the small bubbles rise is the negative ( ) wire. This wire should 
be connected to the negative battery post, marked Neg. or ( ). The 
other wire, which is positive (+) should be connected to the positive 

FIG. 210. Direct current charging 



battery post marked Pos. or (+), but not until the proper amount of re- 
sistance has been determined. 

If the direct current is at 110 volts any of the following sets of lamps 
can be used as a resistance to permit a current of 4 amp. to flow into the 
battery to charge it: 

8-110 volt, 16 c.p. (50 watt) carbon lamps. 
4-110 volt, 32 c.p. (100 watt) carbon lamps. 
16-110 volt, 25 watt mazda or tungsten lamps. 
7-110 volt, 60 watt mazda or tungsten lamps. 

FIG. 211. The Wagner rectifier charg 


The charging operation should continue for 24 to 30 hours, or for two 
periods of 15 hours each. 

If the voltage or pressure is 220 volts, use sixteen 220-volt lamps of 16 
c.p. each, or eight lamps of 32 c.p. each; and charge for 24 to 30 hours. 

If only alternating current is available the batteries can be charged by 


a rectifier (see Fig. 211) which can be procured through an electrical sup- 
ply house. A rectifier is an electrical device for changing alternating to 
direct current. In ordering, state the voltage and frequency of the line 
from which the charging current is to be taken. The ordinary lighting 
circuit has a voltage of 110 and a frequency of 60, but it is best to get 
this information from the electric light company. In addition to this, 
the voltage and capacity of the battery must be given. To charge the 
battery through a rectifier, connect the rectifier in the line, as shown in 
Fig. 211, following the directions accompanying the instrument. 

136. Wiring Systems. Electric starting systems may be of the single 
wire or the two wire system. In the two wire system, each unit, such as 
lamps, motor, and coil, has two wires running to the battery. In the 
single wire system, one side of the 

battery is grounded, that is, one wire pBBHHBHB 
is bolted to the frame of the car, and 
each unit has only a one wire connec- 
tion. In this method it is necessary 
to have some sort of cut-out, so that 
if the single wire should become 
grounded to any metallic part, it 
would not injure the battery. Any 
ground on the single wire system 
would, of course, short-circuit the bat- 
tery. The cut-out will allow only a 
certain amount of current to flow and i 
anything in excess of this will cause FlG . 212. Ward-Leonard controller, 
sufficient magnetism in the core of the 

cut-out to break the circuit. This action can be detected by a clicking 
noise, similar to the working of a telegraph instrument. 

There are a large number of starting and lighting systems on the 
market, the details of which we will now take up. The most important 
technical features to study are the different methods of controlling the 
output of the dynamo. 

137. The Ward-Leonard System. The Ward-Leonard constant cur- 
rent type of controller is shown in Fig. 212 and operates as follows: 
The proper charging of the battery is automatically regulated by the 
controller. When the car speed becomes approximately 7 miles per hour, 
the dynamo armature will give a voltage sufficient to charge the batteries. 
The circuit between the dynamo and the batteries is normally open, but 
when the voltage of the dynamo becomes proper for charging, the coil 
A on the magnet core B magnetizes the core sufficiently to attract the arm 
C. This arm moves toward the core B, and thus two spark-proof 
points D and D' are brought together, establishing the circuit be- 



tween the battery and the dynamo, and the dynamo begins to charge 
the batteries. 

Unless some method of controlling it is adopted, the dynamo voltage 
increases with the speed. The dynamo should charge at about 7 miles 
per hour, but when the car runs at a much higher .speed, as 15 to 60 
miles per hour, it is desirable that the dynamo voltage shall not increase. 
If allowed to increase, such an excessive dynamo voltage would 
tend to cause sparking at the brushes, excess current and consequent 
trouble at the commutator, and excessive wear and heating of the bear- 

FIG. 213. Ward-Leonard wiring diagram. 

ings. It would also cause an excessive amount of current to flow through 
the battery. To prevent this, the strength of the dynamo field, and con- 
sequently the output of the dynamo, is made dependent on the touching 
of the two points E and E'. The coil F on the magnet core G carries 
the armature current, and if this current becomes a certain amount 
(usually in practice 10 amp.) the core becomes sufficiently magnetized to 
attract the finger H. This separates the contacts E and E', and a re- 
sistance M is inserted in the field circuit. This weakens the fields and 
causes the amperes to decrease. When the current decreases to a pre- 
determined amount (say 9 amp.), the coil F does not magnetize the core 
Cr enough to overcome the pull of the spring J. The spring pulls together 



the points E and E'; the full field strength is restored and the current 
tends to increase. Under operating conditions the finger H automatically 
and rapidly vibrates at such a rate as to keep the current constant. 
As a result, the dynamo will never charge above a predetermined amount 
(10 amp.) no matter how high the speed of the car, but will produce a 
substantially constant current. 

In case the engine speed becomes so low that the dynamo volts are 
less than those of the battery, the magnetism caused by the coil A, 
Fig. 212, is weakened so that the spring K pulls the contacts D and D f 
apart. Thus, the circuit between the dynamo and battery is opened 

FIG. 214. Installation of Ward-Leonard system. 

when the dynamo speed is too low for proper charging. An auxiliary 
series coil L on core B acts to insure the perfect demagnetization of the 
core on reversal of current. 

The technical internal wiring diagram, in Fig. 213, shows the con- 
nections of the dynamo, the battery and the controller. Figure 214 
shows a typical installation and wiring layout for the complete two-unit 
starting and lighting system. The connections of the motor are very 
simple. There are two wires from the battery to the motor, with a 
switch operated by the foot pedal. This pedal also shifts the starting 
gears into mesh with the teeth on the flywheel. When the engine starts, 
the foot pedal is released, the gears are disengaged, the switch opened 



and the motor becomes inoperative until it is wanted to start the engine 

138. The Delco System. A single-unit motor-generator is used in this 
system. This unit also carries, mounted on it, the ignition system. A 
general view of a Delco system is shown in Fig. 215. The motor-generator 
has separate sets of brushes, commutator, and windings one used when 
serving as a motor and one when acting as a generator. It also has two 
driving connections. When acting as a generator, it is usually driven 
from the pump shaft by a clutch connection as shown at the right in Fig. 
216, which shows the motor-generator as used on the 1915 Buick cars. 
When the starting pedal is operated, this clutch is disconnected, the gear 

FIG. 215. Delco starting and lighting system. 

connection is made from the motor pinion to the flywheel, the brushes are 
removed from the generator commutator and the motor brushes put into 
contact with the motor commutator. When the pedal is released, the 
connections are made to operate as a generator. 

Voltage Regulator. The Delco system of current regulation uses a 
resistance coil immersed in a tube of mercury, as shown in Fig. 217. 
This instrument serves to control the amount of current flowing from the 
generator to the storage battery. By referring to Fig. 217 the construc- 
tion and operation of this device will be made clear. A magnet coil A 
surrounds the upper half of the mercury tube B. Within this mercury 
tube is a plunger C, comprising an iron tube with a coil of resistance wire 



wrapped around the lower portion on top of a special insulation. One 
end of this resistance wire is connected to the lower end of the tube, the 
other end being connected to a needle D carried in the center of the 
plunger. The lower portion of the mercury tube is divided by an 
insulating tube into two concentric wells, the plunger tube being partly 
immersed in the outer well, and the needle in the inner well. The space 
in the mercury tube above the body of mercury is filled with an especially 
treated oil which serves to protect the' mercury from oxidization, to 
lubricate the plunger, and to form a dash pot for the plunger. Inasmuch 
as the voltage of the storage battery varies with its condition of charge, the 
intensity of the magnetic pull exerted by the magnet coil A upon the 


\W fnll 

FIG. 216. Delco motor-generator. 


plunger C varies, and causes the plunger to move in and out of the mercury 
as the voltage changes. When the battery is in a discharged condition, 
the plunger C assumes a low position in the mercury tube. When the 
plunger is at a low position, the coil of resistance wire carried upon its 
lower portion is immersed in the mercury, and as the plunger rises the coil 
is withdrawn. Now the current to the shunt field of the generator must 
follow a path leading to the outer well of mercury, through the resistance 
coil wound on the plunger tube, to the needle carried at the center of the 
plunger, into the center well of mercury and out of the regulator. 

It will be seen that, as the plunger is withdrawn from the mercury, 
more resistance is thrown into this circuit, due to the fact that the current 
must pass through a greater length of resistance wire. This greater 
resistance in the field of the generator causes the amount of current flow- 
ing to the battery to be gradually reduced as the battery nears a state 
of complete charge, until finally the plunger is almost completely with- 
drawn from the mercury, throwing the entire length of resistance coil into 
the shunt field circuit, thus causing a condition of practical electric 



balance between the battery and generator, and obviating any possi- 
bility of overcharging the battery. 

Automatic Cut-out Relay. The automatic cut-out, Fig. 218, is located 
between the voltage regulator and ignition relay, in the apparatus box. 
This instrument closes the circuit between the generator and the storage 
battery when the generator voltage is high enough to charge the storage 
battery. It also opens the circuit as the generator slows down and its 
voltage becomes less than that of the storage battery, thus preventing the 
battery from discharging back through the generator. The cut-out 

FIG. 217. Delco voltage regulator. FIG. 218. Delco cut-out relay. 

relay is an electro-magnet with a compound winding. The voltage coil, 
or fine wire winding, is connected directly across the terminals of the 
generator. The current coil, or coarse wire winding, is in series with the 
circuit between the generator and the storage battery, and the circuit is 
opened and closed at the contacts A. 

When the engine is started, the generator voltage builds up and when 
it reaches about 6 volts the current passing through the voltage winding 
produces enough magnetism to overcome the tension of the spring B, 
attracting the magnet armature C to core D, which closes the contacts A. 
These contacts close the circuit between the generator and storage battery. 



The current flowing through the coarse wire winding increases the pull on 
the armature and gives a good contact of low resistance at the points of 

When the generator slows down and its voltage drops below that of 
the storage battery, the battery sends a reverse current through the coarse 
wire winding, which kills the pull on the magnet armature C. The spring 
B then opens the circuit between the generator and battery, and will hold 
it open until the generator is again started up. 

139. Gray and Davis Starting and Lighting System. The Gray and 
Davis starting and lighting system consists of a 6^ volt shunt wound 
generator for charging the battery and furnishing current for the lights, 
and a series wound motor for cranking the engine. 




FIG. 219. Gray and Davis generator. 

The generator or dynamo is shown in Fig. 219. This generator has 
two shunt field windings, so arranged that the field strength or magnetism 
automatically increases as additional load comes on. The technical 
wiring diagram for the whole starting and lighting system is shown in 
Fig. 220. 

Regulator Cut-out. The regulator cut-out, shown in Fig. 221, per- 
forms two duties: first, to regulate the dynamo for uniform output; sec- 
ond, to connect the dynamo into the system only when sufficient current is 
generated to charge the battery and to disconnect the dynamo from the 
battery when the dynamo slows down so that the current is insufficient 
to charge the battery, and thus prevent the battery from discharging 
through the dynamo. 

When the dynamo is at rest, the cut-out points are open and the 



FIG. 220. Technical wiring diagram with grounded switch Gray and Davis 
starting and lighting system. 



regulator points remain closed. As the dynamo first speeds up, the regu- 
lator points remain closed. Thus, the field resistance is cut out, permit- 
ting the dynamo to build up under full field strength. When the proper 
voltage is reached, the cut-out points close, permitting current to flow 
through the series winding to the system. 

As the dynamo speed increases beyond that necessary for full output, 
the pull of the shunt winding attracts the regulator armatures. This re- 
duces the pressure at the regulator points and inserts a resistance into 
the field circuit, which prevents further increase of output. The vary- 
ing of the pressure at the points, which allows the resistance to be put 
into the circuit, is intermittent. The frequency is in proportion to the 
speed variation. 


smrTER roRK 


FIG. 221. Gray and Davis regulator 
cut-out mounted on dynamo. 

FIG. 222. Gray and Davis starting 
motor and connections. 

The dynamo terminals are marked B and L. B is negative ( ). 
It is the end of the regulator cut-out series winding, and connects to the 
battery through the indicator. L is also negative ( ). It is con- 
nected to the series winding at a given distance from the end and con- 
nects to the lamps through the lighting switch. The positive brush- 
holder of the dynamo connects or " grounds" to the dynamo frame. 
Therefore, the dynamo frame is positive (+). Connections between the 
dynamo and the regulator are as follows: 

The three terminals at the end of the regulator cut-out opposite the 
terminals marked B and L connect to the dynamo windings, as shown in 
the wiring diagram. 

A connects to dynamo negative ( ) brush. 

FI connects to the one field coil. 

F connects to the other field coil. 

The starting motor and its connections are shown in Fig. 222. The 

starting motor cranks the engine until it runs under its own power. It 



is the link between battery and engine. It converts electrical into 
mechanical energy. Electrically it is connected to the battery through 
heavy cables and the starting switch. Mechanically it is connected to 
the engine through a gear reduction having a sliding flywheel-engaging 
pinion and an over-running clutch. 

The sliding engaging pinion and the starting switch are operated 
by the same operation of the starting pedal, so that electrical and me- 
chanical connection and disconnections occur at the same time. 

When the starting switch is closed, the electrical energy stored in the 
battery is instantly transmitted to the motor, causing the armature to 
rotate. This mechanical energy is transmitted through the gears and 
over-running clutch to the engine, causing it to rotate. 

When the starting pedal is pressed to the full limit of its travel, it 
moves the switch rod in the direction of the arrow in Fig. 222. This 

moves the sliding pinion forward and 
closes the starting switch. If the 
sliding pinion is in a meshing posi- 
tion, it slides into mesh with the fly- 
wheel gear; but if the pinion teeth, 
instead of sliding between, should 
strike the ends of the flywheel teeth, 
the switch rod completes its travel, 
which compresses the shifter fork 
spring and closes the switch. When 
the pinion begins to turn, the com- 
pressed spring throws the sliding 
pinion into full engagement with the 
flywheel gear and permits the start- 
ing motor to crank the engine. 
When the engine picks up, the roll 
clutch prevents the engine from driving the starting motor, as the gears 
are in mesh until the starting pedal is released. 

Over-running Clutch. The purpose of the over-running clutch is to 
permit the engine, when cranked by the starting motor, to pick up with- 
out speeding up the starting motor, which is temporarily connected to the 
engine while the starting pedal is pressed. This over-running clutch 
is merely a roller ratchet connection between one of the gears and its 
shaft. This is shown on Fig. 222 and is shown more in detail in Fig. 
223. The gears 1 and 2 are shown in the reversed position in Fig. 223 
from that which they occupy in Fig. 222. 

When the starting motor pinion No. 1 of Fig. 223 is rotated in a 
counter-clockwise direction, the intermediate gear No. 2 rotates clock- 
wise; the rolls No. 3 are thus rolled into the wedge angles between the 

FIG. 223. Gray and Davis over-run- 
ning clutch. 



curved surface of the clutch center No. 4 and the inner surface of the 
intermediate gear No. 2, with increased pressure until the friction is 
sufficient to drive intermediate shaft No. 5, which is keyed to clutch 
center 4. 

Springs No. 21, back of the plungers No. 22, keep rolls No. 3 firmly 
within wedge angles so that they grip as soon as the starting motor 
turns. When the engine runs faster than when rotated by the starting 
motor, the rolls are released from the wedge angles, and the clutch center 
4 can run ahead without carrying the gear 2 with it. 

140. Wagner Starting and Lighting System. The two-unit Wagner 
system consists of the charging generator, Fig. 224, the starting motor, 
Fig. 225, and the generator relay, Fig. 226. The wiring may be either 
the two wire or single wire system at the option of the manufacturer. 

FIG. 224. Wagner generator. 

The method of connecting the generator to the engine may be by a 
silent chain or by spur or spiral gears. The starter motor may be con- 
nected to the engine shaft by chain and over-running clutch, or by pin- 
ion meshing with the flywheel and operated by the Eclipse Bendix system, 
similar to the Westinghouse clutch shown in Fig. 229. The starting 
motor turns the engine over at about 100 r.p.m., which is fast enough to 
start on most magnetos. 

In Fig. 224, E is the commutator and F, G, H, and / are the brushes. 
The brushes H and I collect the current from the commutator and fur- 
nish this current for charging the battery through the relay. The brushes 
F and G collect from the commutator the current used for exciting the 

The function of the relay, Fig. 226, is to connect the battery to the 
generator when the voltage of the generator is slightly above the voltage 



of the battery. It also disconnects the generator from the battery when 
the voltage of the generator falls below the voltage of the battery. This 
relay consists of two magnet coils, L and M , wound on an iron core N. 
This iron core attracts and repels an iron lever 0. At the end of this lever 
are two main contact points P and Q at which the contact between the 
generator and battery is made and broken. There are also supplied two 
auxiliary contact points R and S which are for the purpose of minimizing 
the sparking at the main contact points P and Q. The coil M, called the 
shunt coil, is connected directly across the two brushes H and /, Fig. 224, 
and therefore the full generator voltage is impressed across the ends of this 
coil. The coil L, called the series coil, is connected in series with the 

FIG. 225. Wagner starting motor. 

battery and generator and therefore this coil carries the charging current 
when the battery is being charged. 

The action of the relay is as follows: When the engine is started, the 
generator is driven by the engine, and it, therefore, increases and de- 
creases in speed with the engine. When the engine is speeded up, the 
generator follows with corresponding increase in speed and the voltage 
of the generator rises as the speed increases. As soon as the generator 
voltage gets to a point above the voltage of the battery, which is ap- 
proximately 6 volts, the coil M , Fig. 226, pulls the iron lever toward the 
magnet core, thereby closing the contact at the points P-Q and R-S. 
As soon as this contact is made, the generator is connected to the battery, 
and a charging current will flow from the generator to the battery through 
the series coil L, which is in series with the generator and battery. The 
generator continues to charge as long as these contact points P-Q and R-S 
remain together, but when the engine speed is decreased, so that the 
generator voltage falls below the battery voltage, the battery will dis- 


charge through the generator and therefore through the coil L. This 
discharge current, being in the opposite direction from the charging current 
will neutralize the effect of coil M and allow the spring T to pull the lever 
away from the magnet core, thereby opening the contact at the points 
P-Q and R-S. As soon as these contacts open, the battery is " off charge." 
The engine speed at which this relay closes corresponds to a car speed of 7 
to 10 miles per hour. 

Studebaker automobiles use the Wagner system and are equipped 
with an instrument called a Battery Indicator or Tell-tale. This instru- 
ment is installed on the dashboard of the car and is connected in the 
battery circuit. The tell-tale gives indication of battery current, showing 

M L 



FIG. 226. Wagner relay. 

off when no current is being taken from, or being put into, the battery; 
discharge when current is being taken out of the battery by lights, ignition, 
or horn; and showing charge when the generator is charging the battery. 
141. The Westinghouse Single-unit System. The Westinghouse 
electric starter-lighter equipment consists of a motor-generator. In the 
motor-generator the functions of both starting and lighting are combined 
in one machine. A 12-volt system is used. The motor-generator is 
permanently geared or chain-connected to the engine. When the circuit 
is closed by the starting switch, the motor windings take current from 
the battery and drive the engine until firing takes place. The motor- 
generator is then driven by the engine, and, as speed increases, it soon 



generates battery voltage. At all higher speeds it charges the battery and 
furnishes the current for the lights. 

There is an emergency feature on the Hupmobile that prevents stalling 
of the engine. At low speeds the motor-generator acts as a motor and 
assists the engine, causing an immediate restart in case of stalling. 

It should be remembered that at speeds of less than 9 miles per hour, 
with engine on high gear the motor-generator acts as a motor, assists 
in propelling the car, and therefore takes current from the battery; and 
if such running is indulged in to any extent the battery will become 
exhausted. Also, allowing the engine to idle at low speeds will discharge 
the battery. A little care in avoiding low speeds and engine idling will 

FIG. 227. Westinghouse Ford outfit. 

prevent this. Figure 227 shows the Westinghouse single-unit system for 
Ford cars, while the wiring diagram is given in Fig. 228. 

142. Westinghouse Two-unit System. 'The starting motor for the 
Westinghouse two-unit system is shown in detail in Fig. 229. It may 
be equipped with either a non-automatic or an automatic pinion-shift, 
flywheel drive. 

Figure 230 shows the mechanical and electrical connections of motor 
and switch for non-automatic pinion-shift, flywheel drive. At A is 
shown the "off" position of the shift pinion and switch contactor. 
Pressure on the starting lever moves the shift rod first to the position 
shown in B, closing the motor circuit at P and P' through the resistance 
R; this starts the motor at low speed. Further motion of the shift rod to 
position C opens the electric circuit but the motor and pinion continue 



to turn, owing to their momentum. When position C is reached, the 
pinion is still turning slowly, so that it can not fail to mesh with the gear, 
but as power is turned off the motor, there is no difficulty in sliding the 
teeth into full engagement. As soon as the teeth do engage, further foot 
pressure on the starting lever shifts the rod to position shown in D, 
closing the electric circuit at Q after the pinion and gear have meshed a 
sufficient distance to present a good bearing length on the teeth; this 

Head Lights- 


Tail Light 

FIG. 228. Wiring diagram for Westinghouse Ford outfit. 

connects the motor directly to the storage battery so that full power is 
impressed, and it turns the engine over until the starting lever is released 
or the engine picks up on its own power. There is an over-running clutch 
between the flywheel pinion and the motor, so that, if the pedal is not 
promptly released when the engine picks up, the motor is not driven by the 





FIG. 229. Westinghouse starting motor disassembled. 

FIG. 230. Connections of Westinghouse starting motor with non-automatic 
pinion shift. 



In the Eclipse-Bendix pinion-shift, as shown in Fig. 231, the starter 
motor is fitted with a special threaded shaft which automatically shifts 
the pinion into mesh with the flywheel when the starting switch is closed. 
When the switch is closed, the full battery voltage is impressed on the 
motor, and it starts immediately. The pinion, when the motor is at rest, 
is within the screwshaft housing and entirely away from the flywheel 
gear. The threaded shaft is connected to the reduction gear shaft by a 
spring which thus forms a flexible coupling. As the load is not large 
enough to compress the spring when the motor starts, the threaded shaft 
is immediately revolved by the spring in released position. The pinion 
moves out on its shaft by virtue of the revolving threads, until it reaches 
the flywheel. If the teeth of the pinion and flywheel meet instead of 

tortmg Motor 

Starting Switch r 

'orting Motor 

A, With hand or foot 
operated starting switch. 

B, With electro-magnetic starting switch 
controlled by push button. 

FIG. 231. Connections 

of Westinghouse starting 
pinion shift. 

motor with Eclipse-Bendix 

meshing, the spring allows the pinion to revolve until it meshes with the 
flywheel. When the pinion is fully meshed into the flywheel teeth, the 
spring compresses, and the pinion is then revolved by the motor as 
through a continuous shaft, turning the engine over. When the engine 
fires and the peripheral speed of the flywheel continuously exceeds that 
of the driving pinion, it forces the latter out of mesh, and it is returned to 
its original position in the screwshaft housing. 

The Westinghouse lighting and starting generator, as shown in detail 
in Fig. 232, is operated by belt, chain, or gear drive from the engine and 
furnishes current to the storage battery and lights. While the engine is 
stopped or running at very low speed, the lights are supplied entirely by 
the battery. A magnetic switch in the generator automatically con- 
nects the generator to the lighting system and battery when the engine is 
running at approximately 8 miles per hour car speed on. direct drive. 
When running on the gears,the switch closes at a much lower car speed. 
If no lights are then in use, the battery begins to be charged when this 
switch makes the electrical connection. If the lights are burning, the 



generator furnishes part of the current to them; as the speed increases, the 
proportion of current supplied by the generator increases, until at high 
speed the generator supplies all of the current to the lights and in addition 
charges the battery. The amount of current the generator furnishes to 
the battery depends upon the number of lamps burning and upon the 
speed of the engine. 

143. The U. S. L. Electric Starting and Lighting System. This is a 
unique system in which a single unit motor-generator is connected directly 
to the engine shaft, taking the place of the flywheel. 

The motor-generator consists of a stationary housing, a set of fields 
complete with poles and coils, an aluminum case, and a dust ring, as 


- . 


FIG. 232. Westinghouse starting and lighting generator disassembled. 

shown in detail in Fig. 233. The armature replaces the flywheel of the 
engine, being attached to the crank shaft in its stead as shown in Fig. 234. 
When the starting button is pressed down, the current from the battery- 
starts the electric motor. This revolves the crank shaft of the engine. 
With the switch of the ignition coil in battery position, the explosions will 
commence. The starting button should be quickly released, thus auto- 
matically changing the electric motor into an electric generator. As the 
speed of the engine increases, the generator gradually commences charging 
the battery, restoring the current discharged during the starting operation. 
Regulator. The regulator is located on the dash under the cowl and 
instrument board. It performs four principal functions: 1, closes the 
switch when the generator voltage is sufficient to charge the battery; 
2, opens the switch when the generator voltage is insufficient and the 


current reverses; 3, regulates the maximum charge to the battery; and 4 
controls the generator voltage on open battery circuit. 

An indicating arrow is visible through the window in the regulator 
cover when the switch is closed and the storage battery is being charged. 
It disappears when the contact is broken. The switch should close when a 
car speed of 10 to 12 miles per hour is attained, and open when the speed 
falls below about the same rate, or when the motor stops altogether. 

The regulator consists of a magnet coil which pulls the switch lever 
into contact when the proper car speed is attained. It also acts on a 
carbon pile lever and controls the field current by increasing or decreasing 
the resistance through the carbon discs at the top of the regulator. 


Fia. 233. Details of U. S. L. system. 

If the engine does not turn over when you first press on the button, 
immediately let up the button and try again several times quickly. Do 
not hold your foot on it long, as this will needlessly drain the current from 
the battery. 

If the motor fails to respond when the starter button is pressed 
several times quickly, the battery is too low. In such cases, do not continue 
to hold the starting button down ; release it, and crank the motor by hand, 
running it at a charging rate of 10 to 15 amp. giving the generator an 
opportunity to recharge the battery. If you repeatedly press the starting 
button without running the engine, it will only be a question of time before 
the battery will be exhausted. 

144. Jesco Single -unit Electric Starter and Lighter. The complete 
system consists of a starter-generator, with controller and starting switch 


mounted thereon, in connection with a 6 volt, 100 amp.-hour storage 
battery, switch, and wiring for lights. The starter-generator is connected 
either by coupling, by silent chain, or by gears to the crank shaft of the 
engine, at a ratio of either one to one, or two to one. 

The electric machine performs as a series motor at time of starting 
and as a shunt generator for storing current in the battery and supplying 
the lights. As a starter, a gear reduction is automatically engaged, and 








FIG. 234. Section of U. S. L. motor-generator. 

after the engine starts, this transmission locks by action of a multiple disc 
clutch, and no gears are in operation. This works automatically and 
requires little attention, outside of oiling. The electrical regulating mech- 
anism is contained in the little box on top of the starter-generator. 
The regulation is taken care of by a differential shunt field in connection 
with an automatic regulator. 

Charging begins at approximately 8 miles an hour car speed. At 15 
miles an hour the maximum charging rate is reached and, by regulation, 
remains constant through all speeds in excess of that amount. The 


battery cut-out automatically disconnects the battery when the generator 
is not charging, preventing a back flow from battery to machine. 

The wiring is extremely simple, having only two leads from starter- 
generator to battery, with the lighting of car and the indicating meters 
arranged as desired. The Jesco system as used on a Continental six 
engine is shown in Fig. 235. 

145. Care of Starting and Lighting Apparatus. A periodical in- 
spection should be made of wiring, insulation and all connections. Wir- 
ing and connections should be protected against grease, oil, and me- 
chanical injury. 

FIG. 235. Jesco starting installation. 

Use the same consideration for your auto lighting system that you 
do for electric light in your house. Do not leave your car all night with 
all lights burning and expect to find a well charged battery in the morning. 

Be sure that all wires are perfectly insulated and not in contact 
with any moving parts, as the constant rubbing will wear off the insula- 
tion and the vibration will cause the connections to become loose. 

All permanent connections should be well soldered, all stray strands 
of wire removed and the joints properly taped in order to prevent loss 
of current from short circuits. If wires must be run where there is 


liable to be grease, oil, or water, they should be protected by conduit 
or other oil or waterproof material. Either oil or water will cause the 
insulation on the wire to be of very little value. 

The generator should be inspected about every month and kept 
clean. The commutator may become rough and blackened and should 
'be cleaned by holding a piece of fine sandpaper against it while rotating. 
Then carefully remove all metallic particles from the commutator bars 
that might cause a short circuit between them. A short circuit may also 
be caused by carbon dust from the brushes. 

The brushes should always have a perfect bearing surface on the 
commutator. The general cause of a poor bearing is that the carbon 
brush sticks in the brush holder. It may be taken out and filed down so 
that it will slide easily in the holder. 

When putting in new brushes, make sure that they fit perfectly 
on the commutator. It is also a good policy to use only the brushes sent 
out by the manufacturer of the machine. 

If there is a grounded wire in the machine, or if a commutator segment 
becomes loose, the armature should be returned to the factory for 

The carbon brushes contain sufficient lubricant for the commutator 
so that it is not necessary to use any oil or grease of any kind. If grease 
or oil should accumulate on the brushes or commutator, it should be 
wiped off with a dry cloth. 

The starting motor is intended to perform one function only, viz., 
to spin the engine, and should only be used for such purpose. Any 
attempt to propel the car by the starting motor or indulge in the needless 
use of same will result in trouble. Such experiments are of no material 
value and it is no test of the power of the starting motor, but simply 
imposes an extravagant demand on the battery. If these practices are 
indulged in they will result in a complete discharge, which is detrimental 
to the life and service of the storage battery. 

146. Starting Motor Troubles. The closing of the starting switch 
completes the circuit between the battery and the motor, and puts the 
starter in operation. If the starter does not turn the engine over, release 
the switch at once and ascertain if all connections are tight and secure, 
and inspect the battery. If the starting motor turns the engine over 
very slowly, it is evident that the battery is weak or the engine stiff. 
If the starting motor is turning the engine over at a reasonable cranking 
speed and the engine does not fire, remember that the starting motor is 
performing its duty, so do not let the starting motor continue to crank 
the engine longer than necessary, as a needless drain is placed on the 
battery. If the engine does not fire, it is evident that the trouble is 
confined to the carburetor or ignition. 


147. Generator Troubles. A simple test to determine if the generator 
is properly operating is, first, to switch all the lights on with the engine 
idle; second, to start the engine and run it reasonably fast. If the lights 
brighten perceptibly after starting the engine, it proves that the generator 
is properly delivering current. This test must necessarily be conducted 
in the dark, either in the garage, or preferably, at night time. Generator 
troubles will be manifested by dim lights when the engine is running at a 
medium rate or by failure to keep the battery charged. The trouble 
may be caused from, first, grounds or short circuits in the field windings; 
second, increased resistance in circuit, caused by dirty commutator or 
brushes, weak brush springs or poor material in the brushes (poor ma- 
terial in brushes causes sparking and overheating) ; third, grounds in the 
armature, caused by defective insulation or carbon deposits on the 
commutator short-circuiting the copper bars; fourth, circuit breaker or 
regulator not properly adjusted so that the battery is not cut in at proper 
time. The contact points may become dirty or corroded or may be 
burned by an excess of current, generally from a reverse current from 
the battery. 

148. Battery Troubles. Battery troubles may be detected by failure 
to turn the motor or by the lights burning dimly when the engine is 
stopped. Battery troubles can be traced to improper charging; loss 
of electrolyte; short circuits, either external or internal; overloading, 
caused by using light bulbs of too large capacity; burning lights when not 
necessary; and propelling car with starting motor. External short 
circuits may be caused by broken insulation so that two bare wires come 
together or come into contact with the frame of the car or other conducting 
material, or may be caused by acid on top of battery forming circuit 
between terminals. Internal short-circuiting is explained in Art. 134. 

If the starting motor will not crank the engine, the trouble may be 
looked for as follows: 

1. Battery discharged. 

2. Broken circuit caused by worn out or dirty brushes or weak 
springs, or broken connections or short circuits in any part of the wir- 
ing or switches. A dirty commutator will have the same effect as 
dirty brushes. 

If the starting motor cranks the engine very slowly, the trouble 
may be caused by the battery being partly discharged or by an excess of 
resistance in the circuit. The increased resistance may be caused by 
loose connections in wiring, poor contacts in switch, dirty brushes or 
commutator, brushes made from unsuitable material or not held firmly 
on the commutator. 

149. Winter Care of Batteries. If the car is not to be used for some 
time, as in the winter, the batteries should be inspected before the car is 


used for the last time. Water should be added to the cells, if necessary, 
so that it will thoroughly mix with the electrolyte when the car is driven. 
When the car is laid up, the specific gravity of the electrolyte should 
register from 1.27 to 1.29. In this condition there will be no danger of 
freezing in any climate. The battery should be charged every two 
months during the "out of season" period, either by running the engine, 
or by charging from an outside source. If either of the above methods 
is impossible, and there is no garage convenient that is equipped for 
charging batteries, the battery may be allowed to stand without charging 
during the winter, providing it is fully charged at the time the car is 
laid up. Much better results, however, and longer life of the battery 
will be obtained by giving the periodic charges. The wires of the 
battery should be disconnected during the "out of season" period in 
order to prevent any slight leaks that might occur in the wiring. 

150. "Don'ts" on Starting Equipment. Don't disconnect the battery 
and start the engine up with any of the lamps in circuit. This is very 
important as the battery acts as a voltage regulator and, if not con- 
nected, the lamps or fuses in the circuit connected will be blown out 
immediately, due to heavy rise in voltage from the generator. 

Don't attempt to work around the lighting system without dis- 
connecting the battery ground and winding it with tape. It is a very 
easy matter to touch a screw-driver or a pair of pliers from a live wire 
to the frame or to the pipes or engine, thereby causing short circuit and 
blowing out a fuse. When the work is finished, replace the ground wire 
before starting the engine. 

Don't try to repair or readjust any of the instruments supplied. 
Leave this to the manufacturers whose experience in this field will in- 
sure handling the job in a better manner than you can. 

Don't leave the starter button in the socket while the motor is running. 

Don't stamp on the starter button, but press it down deliberately 
and firmly. 

Don't fail to go over the wiring occasionally and see that all binding 
posts are tight and free from corrosion. 

Don't fail to remember that the mechanism is an electrical starter 
and not a motor for vehicle propulsion. 

Don't expect the starter to spin the motor at a maximum cranking 
speed if the battery voltage is run down. Endeavor to run the car with 
fewer lights for a while and allow the voltage to pick up. 

Don't abuse the electric starter. The mechanism is strong and 
durable and guaranteed for the purpose intended, but is not guaranteed 
against rough treatment or inexcusable abuse. 

Don't fail to inspect all terminals occasionally and see that the 
tape which protects these terminals from short-circuiting is in good 


shape. In case this has become unwrapped, it is advisable to replace 
immediately with fresh insulating tape of good quality. 

Don't try to hook up additional electrical equipment without care- 
fully going over the wiring diagram to find the proper place for such a 

Don't fail to see that the ground wire from the battery has a good 
contact between the terminal and frame. 

Don't fail to carry extra fuses and lamp bulbs. 



151. Classification of Troubles. The manufacturers of automobiles 
are constantly striving to simplify the design and construction of all 
parts in order to reduce the number of troubles which are a constant 
source of worry to the automobile owner and driver. They have been 


Insulation worn off, 
cable not attached 

Broken, fouled, loose, \ 
gap too wide "^ A 


Filled with sediment 

I Loose 


Pitted, scored. ~~~~- 
covered with carbon 

Not tight 


Bent, stuck 


Too weak, broken, 
out of place 


To much or too /it tie 

Disconnected from 
throttle valve rod 

Soaked or logged 

Stem bent seat 
leaks, valve stuck 
on seat 



Bent or stutk 

Contour worn 

Loose, broken, 


Worn, too loose, 
out of round ', 

Worn, loose 

Scored, worn 





Contact points not 
proper/y adjusted 

Gears not meshed 


Worn, out of 

Loose, worn 

Bearings worn 

FIG. 236. Chart showing location of common mechanical troubles of engines. 

quite successful in reducing troubles to a minimum; as a matter of fact, 
the possible troubles on the modern car are now few in number com- 
pared to those of not a great many years ago. The troubles now com- 
monly experienced are those inherent in every man-made machine which 
is subject to the wear and tear of everyday use. 



It is obviously impossible in many cases to give a direct statement of 
a cure for all of the various symptoms which are likely at some time or 
other to confront the motorist, as some symptoms may be due to any 
one or more of several different causes. All that can be done is to offer 
a few general suggestions which will assist him to diagnose his own 
specific troubles and apply the proper remedy. 

The automobile is a fine piece of machinery and the service from it 
will depend upon the care and attention given to it. Many of the 
troubles on the modern automobile are due to uncalled for adjustments 
and investigations by the motorist. Although good care and attention 
must be given in order to get efficient service, it is good policy to 
leave well enough alone and not do any unnecessary tampering, nor 
try to improve upon the operation or construction as planned by the 

The more common motor car troubles can be divided into the follow- 
ing general headings: 

I. II. III. 

Power plant troubles Transmission troubles Chassis troubles 

(a) Mechanical parts of engine. (a) Clutch. (a) Wheel hubs. 

(6) Carburetting and gasoline (6) Change gears. (6) Steering gear. 

system. (c) Differential. (c) Brakes. 

(c) Ignition. (d) Rear axle. (d) Springs. 

(d) Lubricating and cooling. (e) Tires. 

(e) Starting and lighting. 

152. Power Plant Troubles. Any derangement in the power plant 
will show itself by one of the following symptoms. Under each symp- 
tom is given the common causes with a reference to the discussion "on the 

(1) Engine Fails to Start. 

(a) Poor compression. See Art. 153. 

(6) Engine cylinder flooded. See Art. 154(e). 

(c) Carburetor adjustment not right. See Art. 154. 

(d) Water in gasoline. See Art. 154(j). 

(e) Carburetor frozen. See Art. 154 (g). 
(/) Out of gasoline. See Art. 154(t). 
(g) Engine too cold. See Art. 154(/). 
(h) Ignition switch off. 

(i) Foul or broken plugs. See Art. 155(6). 

0') Weak batteries or magneto. See Art. 155(e,/, and g). 

(k) Vibrators not properly adjusted. See Art. 155(A). 

(0 Wiring system out of order. See Art. 155(d, ;, and k.) 

(2) Engine Misses at Low Speeds. 

(a) Poor compression. See Art. 153. 

(b) Mixture too lean or too rich. See Art. 154 (a and 6). 


(c) Spark plug gap too wide. See Art. 155(6). 

(d) Spark plug cable not connected or short-circuited. See Art. 155 (d). 

(e) Dirty interrupter. See Art. 155 (jfc). 

(/) Dirty or defective spark plug. See Art. 155(6). 
(g) Vibrator not properly adjusted. See Art. 155(h). 

(3) Engine Misses at High Speeds Only. 

(a) Carburetor not set for this speed. See Art. 154 (a and 6). 
(6) Bad spark plug. See Art. 155(6). 

(c) Weak valve spring. See Art. 154(6). 

(d) Timer contact imperfect. See Art. 155 (ft). 

(e) Vibrator points dirty or burned. See Art. 155(h). 

(4) Engine Misses at All Speeds. 

(a) Carburetor not properly adjusted. See Art. 154(a and 6). 

(6) Dirty or broken plug. See Art. 155(6). 

(c) Spark plug gap not right. See Art. 155(6). 

(d) Poor compression. See Art. 153. 

(e) Loose or broken terminals. See Art. 155(d). 

(/) Weak batteries or magneto. See Art. 155(e, /, and g). 

(g) Defective wiring. See Art. 155(d). 

(h) Coil not properly adjusted. See Art. 155(h). 

(i) Gasoline feed stopped up. See Art. 154(6 and h). 

0') Needle valve bent or stuck. See Art. 154(6 and h). 

(fc) Water in gasoline. See Art. 1540')- 

(0 Poor circulation. See Art. 156(6). 

(m) Excessive lubrication. See Art. 156 (a). 

(5) Engine Overheats. 

(a) Lack of proper circulation. See Art. 156 (a). 
(6) Lack of proper lubrication. See Art. 156 (a). 

(c) Slipping fan belt or bent fan blades. See Art. 156(6). 

(d) Too rich a mixture. See Art. 154 (a). 

(e) A weak mixture. See Art. 154(6). 

(/) Running with spark retarded. See Art. 155(0- 

(g) Carbon deposit in cylinders. See Art. 153(/) and 155(m). 

(6) Engine Stops. 

(a) Gasoline tank empty. See Art. 154(i). 

(6) Water in gasoline. See Art. 1540'). 

(c) Carburetor flooded. See Art. 154(d). 

(d) Lack of pressure on gasoline tank. See Art. 154(i). 

(e) Overheating due to poor circulation or lack of lubrication. See Art. 

156(o and 6). 

CO Short-circuiting of wires or terminals. See Art. 155(d and j). 
(g) Disconnected or broken wires. See Art. 155(d). 
(h) Wet batteries or magneto. See Art. 155(d and e}. 

(7) Engine Knocks. 

(a) Carbon deposits in cylinder and on piston heads. See Art. 153 (/) and 

155 (m). 
(6) Spark too far advanced. See Art. 155(0- 

(c) Running motor slow when pulling heavy load on direct drive. See Art. 


(d) Faulty lubrication. See Art. 156 (a). 

(e) Engine overheated. See Art. 155(ra). 

CO Loose connecting rod bearings. See Art. 153(0). 


(g) Loose piston. See Art. 153 (e). 

(h) Loose crank shaft bearing. See Art. 153(0). 

(8) Engine Will Not Stop. 

(a) Short circuit in switch. 

(6) Magneto ground may be disconnected. 

(c) Overheating and carbon deposits. See Art. 155(m) 

(9) Lack of Power. 

(a) Poor compression. See Art. 153. 

(6) Too weak or too rich a mixture. See Art. 154 (a and 6). 

(c) Weak spark. See Art. 155(e, /, g, and h). 

(d) Lack of lubrication. See Art. 156 (a). 

(e) Lack of cooling water. See Art. 155(6). 
(/) Lack of gasoline. See Art. 154 (ft and i). 
(g) Dragging brakes. See Art. 159(c). 

(A) Slipping clutch. See Art. 158(a). 

(**) Flat tires. 

(j) Choked muffler causing back pressure. 

(10) Back-firing Through Carburetor. 

(a) Improper needle valve adjustment. See Art. 154(6). 

(6) Dirt in gasoline passage or nozzle. See Art. 154(6 and h). 

(c) Inlet valves holding open. See Art. 154(6). 

(d) Excessive temperature of the hot water jacket of the carburetor, especially 

in hot weather. This can be remedied by shutting off the water from 
the carburetor jacket and cutting off the hot air supply. 

(e) Spark retarded too far. See Art. 154(6) and 155(m). ' 

(11) Firing in Muffler. 

(a) Weak mixture, slow burning exhaust, igniting unburned charge from pre- 
vious "miss." See Art. 154 (6). 
(6) Valves out of time. 

(c) Too rich a gasoline mixture. See Art. 154(o). 

(d) Occasional missing of a cylinder. 

(12) Starter Witt Not Operate. 

See starter troubles, Chap. VIII. 

153. Mechanical Troubles in Engine. {a) Poor Compression. Poor 
compression is one of the common causes for lack of power. Unless the 
compression pressure is high enough, the explosion will be lacking in force 
and the engine will be weak. The engine can be turned by hand, with 
the ignition off, throttle open, and the compression noted in each cylinder, 
or a more accurate way is to remove the spark plug and screw in a small 
pressure gauge, which should show from 60 to 80 Ib. at the end of the 
compression stroke, depending on the make of engine. Loss of com- 
pression is commonly due to leaky or improperly seated valves, or to leaky 
joints. Leaky thread joints, valve caps, and cracks in cylinder are 
common causes for loss of compression. These can be detected by a 
hissing sound or, if the suspected leak is covered with gasoline or oil, the 
leak will show itself by bubbling through the oil. If the trouble can not 
be located in this manner attention should be given to the valves. 

As a rule, the intake valve requires less attention than the exhaust 



valve, because the former comes into contact with the cool fresh fuel 
charges, whereas the latter is apt to 'become fouled and burnt by the hot 
and dirty exhaust gases. A frequent cause of leaky valves is carbon 
deposit on the valve seats. These deposits prevent the proper seating 
of the valve. The remedy is to clean and grind them. 

b. Grinding Valves. There are several good grinding compounds on 
the market. It is advisable to use a coarse grade in the first operation and 
then to finish off with a finer one to give a polished surface. A very good 
homemade mixture is obtained by making a thin paste of a couple of 
tablespoonfuls of kerosene, a few drops of oil, and enough fine flour 
emery to thicken to the consistency of paste. 

The valve spring must be removed so that the valve may be lifted 
and turned. A moderate coating of the paste is applied to the bevel 
face of the valve. Next rotate valve 
back and forth until the entire bear- 
ing surface is polished bright and 
smooth the full width of the face. The 
valve should never be turned the 
whole way round. Rotate it back and 
forth a quarter turn at most under 
light pressure, lifting it up frequently 
and turning it halfway round before 
seating it again. This method distri- 
butes the friction evenly and elimi- 
nates the possibility of the emery 
scoring the bearings. If no valve 
grinding tool is available, the use of a 
carpenter's brace or bit stock is recommended, as a much smoother 
movement is thus obtained than by using a screw-driver. This method, 
recommended by the Overland Company, is shown in Fig. 237. 

After grinding to a good clean seat entirely free from spots or pits, 
wash the valve, valve seat, and guide thoroughly in gasoline. If the 
stem is rough or gummy, smooth it up with emery cloth but clean it 
afterward before replacing it in the guide. To test the effectiveness of 
your work, mark the valve seat in several places with a lead pencil and 
turn the valve around a few times. If the marks are entirely rubbed off, 
the work may be considered well done. 

(c) Valve Adjustments. Poor adjustments of the valve operating 
mechanism may cause poor compression, even if the valve seats have been 
properly ground in. The valve spring may be broken or too weak to 
close the valve on its seat in the proper time. Sticking of the valves when 
open may also be the cause of low compression. 

The clearance between the valve stem and push rod may be the cause 

FIG. 237. Valve grinding. 


of considerable trouble. This clearance is usually about the thickness 
of a thin visiting card, the exact amount being somewhat different for 
different cars, but never over ^2 m - 

If this clearance for the intake valve is too great, the lift is reduced, 
thus preventing the proper charge from getting into the cylinder. If the 
exhaust valve lift is reduced in the same way, it will be more difficult for the 
exhaust gases to escape. Too much clearance also changes the time of 

Cam Shaft 

FIG. 238. Adjustment of push rod clearance. 

valve opening and closing, causing the valves to open late and close early. 
If, on the other hand, this clearance is too small or entirely absent, the 
valve will open early and close late, or will not close on its seat at all. 

As the valve seats are lowered by continual grinding, the clearance is 
gradually changed. For the proper operation of the valves, careful 
attention should be given to this clearance space. Figure 238 illustrates 
the clearance adjustment on the Overland car. 

A weak spring on the exhaust valve may have a marked effect on the 


operation of the engine. The exhaust valve then opens on the suction 
stroke and burnt gases are again drawn into the cylinder. 

(d) Valve Timing. It is essential that the valves be properly timed 
or set, in order to have the engine operated properly. The valves are 
set at the factory and the necessity for adjusting the timing comes as the 
result of wear on the valve seats, stems, rods, cams, half-time gears, or by 
improper replacement of any of these parts. If the cam shaft has been 
removed, care must be taken to get the gears properly meshed when re- 
placing it. The gears are marked so that replacement is not difficult. 
The proper method of replacing the gears on the Ford engine is shown in 
Fig. 239. It will be noticed that there 
is a prick-punch mark on one tooth of 
the pinion and a corresponding mark 
on the large gear. Before taking a 
cam shaft out, an examination should 
be made and if the gears are not so 
marked it should be done before they 
are disturbed. 

If the clearances are properly ad- 
justed for the push-rods and valve 
stems and if the timing gears are 
properly meshed, the valves should be 
correctly timed, making allowance for 
wear on the cam faces. Most engines 
have the positions at which the valves 
start to open and close marked on the 

circumference of the flywheel. These FlG> 239. Ford cam shaft setting, 
points should be opposite the pointer, showing marked tooth and space on 
usually at the top of the case, when il 

the valves start to open and close. This time can be determined by 
the use of a thin sheet of tissue paper. By placing a piece of the paper 
in the clearance space between the push-rod and valve stem, one can 
tell when the valve opens or closes. 

Valve setting is an adjustment that should be made by an experienced 
mechanic or one thoroughly familiar with the principles of the four-stroke 
engine. The different makers have found by trial the settings that will 
give the best results with their engines and cars. These settings differ 
somewhat according to different conditions. If they are not marked 
on the flywheel, they should be obtained from the manufacturer. 

Figure 240 shows the approximate crank and piston positions for 
the valve events. The inlet may be opened by the different makers, any- 
where from top center to 20 of flywheel motion after center. The inlet 



closes from 25 to 50 past lower center. The exhaust opens 35 to 60 
before lower center and closes from top center to 15 past center. 

(e) Loose Piston or Scored Cylinder Walls. A loose piston or scored 
cylinder walls will cause a marked loss of compression. If the piston is 

Inlet opens. 

Inlet closes. Exhaust opens. 

FIG. 240. Valve setting diagram. 

Exhaust closes. 

not too loose, slightly larger rings may be put on. Sometimes the 
blowing can be remedied by using a heavier cylinder oil. This will 
to some extent remedy the trouble caused by scored cylinder walls, 
although if too badly cut, they must be rebored and new pistons or 
rings fitted in. Again, this is the work of 
an experienced mechanic. 

(/) Carbon Deposits in Cylinder. After 
the engine has been run for some time, 
carbon deposits are liable to collect in the 
cylinder . and on the pistons, especially if 
too much lubricating oil or gasoline has 
been used. The carbon deposit resulting 
from too much lubricating oil is a sticky 
substance, while that from too much 
gasoline is hard, dry, and brittle. These 
deposits, if allowed to collect, become hot 
from the heat of explosions, and cause 
preignition of the fresh charge of gas. 

The best methods of removing carbon 
deposit are to scrape it out or to burn it 
out by means of an oxygen flame. The 
latter method is quicker and by far the 

FIG. 241. Scraping the 

most convenient. The following method is recommended by the Over- 
land Company for the removal of carbon by scraping : 

To scrape the cylinders, remove both inlet and exhaust valve caps. 
Fig. 241, and turn the motor over until the pistons of two cylinders are at 
their top centers. The scraping off of the deposit is done by means of 


tools of different shapes, the tools being bent so as to reach the piston, 
head and the sides and tops of the cylinders. Scrape all removed 
carbon over to the exhaust valve and, when through, turn the motor until 
the exhaust valve lifts, when the carbon may be scraped past the valve 
and into the exhaust passage, whence it will be blown out. For a good 
job, brush the surfaces clean and make sure that no carbon becomes 
lodged between the exhaust valve and its seat. Finally wash with 

In replacing the cylinder plugs over the valves, put graphite grease 
around the threads; this will make a compression-tight joint and also 
make it easier to remove the plugs the next time. Likewise, be sure to 
replace the copper gaskets under the plugs. 

It is an excellent plan to attend to removing the carbon and to grind- 
ing the valves together at the same time. 

Kerosene is also used for the removal of carbon from the cylinders. 
Pour two or three tablespoonfuls of kerosene through the priming cocks 
while the engine is warm. It has a strong solvent action on any gummy 
binding material in the carbon and can be spread over the entire cylinder 
by cranking the engine a few times around. Some motorists inject the 
kerosene through the air valve of the carburetor just before the engine is 
stopped preparatory to putting it away for the night. Kerosene will 
not remove a hard carbon deposit but it will prevent it from forming if 
used regularly about once a week. 

Running the engine on alcohol for a few minutes is another device 
that is sometimes used for burning out carbon deposits. 

(0) Bearing Troubles. The common bearing troubles are those caused 
by the bearings becoming worn and loose, with a consequent knocking. 
Faulty lubrication, clogged oil pipes and oil holes, and dirty oil are the 
main causes of warm bearings. The bearings which are most liable to 
give trouble are the wrist pin bearings, the connecting rod bearings, and 
the main crank bearings. After a bearing has been excessively hot, it 
should be refitted by a mechanic. A loose bearing can be tightened on 
the pin by removing the liners or shims, or by being refitted. 

154. Carburetion Troubles. Improper mixture is the common source 
of carburetor trouble. The mixture is either too rich, that is, too much 
gasoline in proportion to the air, or too weak, that is, too much air in 
proportion to the gasoline. 

(a) Mixture too Rich. A rich mixture shows itself by black smoke 
coming from the muffler, and by overheating and missing of the engine. 
Not only is fuel wasted, but the cylinders become fouled and carbonized. 
A mixture too rich at slow speeds should be corrected by cutting down 
on the gasoline, and at high speeds by increasing the auxiliary air. An 


auxiliary air spring which sticks, a restricted air opening, or a flooded 
carburetor will cause an overrich mixture. 

(b) Mixture too Weak. A weak mixture can be detected by back-firing 
through the carburetor and by occasional muffler explosions. A weak 
mixture, being a slow burning mixture, is still burning when the intake 
valve opens for the following charge. This permits the flame to shoot 
back through the manifold into the carburetor. A weak mixture should 
not be confused with an improperly timed intake valve which opens 
before the burning charge has been exhausted. If the intake valve has a 
weak spring which does not close the valve properly, it may permit back- 
firing through the carburetor. The explosions caused by the valve trouble 
are usually more violent than a back-fire due to weak mixture. A weak 
mixture at low speeds is caused generally by too little gasoline and at high 
speeds by too much auxiliary air and the carburetor should be adjusted 

An air leak in the manifold connections will dilute the mixture with air 
and cause a weak mixture and back-firing. These leaks should be remedied 
before the carburetor adjustments are changed. 

A stuck or bent or obstructed gasoline needle valve may cause a weak 
mixture by shutting off the supply of gasoline. The remedy is obvious. 

(c) Color of Explosive Flame. By opening the priming cocks on the 
cylinders, the color of the flame can be seen as the explosive flame issues 
out of the cocks. A blue flame indicates a perfect mixture, a red flame 
indicates an excess of gasoline, and a white flame indicates an excess of air. 

(d) Flooded Carburetor. If the carburetor float becomes gasoline 
soaked or filled with gasoline, it will not shut off the gasoline float valve 
and the carburetor float chamber will become filled with gasoline. The 
remedy is to take the float out and if it is made of cork, have it dried out, 
painted with shellac and baked. If of the hollow metal type, have the 
float emptied and the hole soldered. A small particle of dirt under the 
float valve will also cause the carburetor to become flooded. 

(e) Flooded Cylinder. If the engine has been cranked for some little 
time and too much gasoline has been sucked into the cylinders, the cylin- 
ders become flooded with almost pure gasoline which condenses in the 
cold cylinders. This charge will not explode. The remedy is to open the 
priming cocks and crank the engine until the overrich mixture has been 
expelled or diluted. The priming cocks can then be closed and the engine 
will usually start. Flooding of the engine can also be caused by priming 
the cylinders with too much gasoline. It sometimes happens that a 
flooded engine can be started without difficulty after standing for several 
hours. The excess gasoline has evaporated in the meantime. 

(/) Cold Weather Starting. In cold weather, when the engine is stiff 
and the gasoline is hard to evaporate, it is necessary to inject a little 


warm or high test gasoline into each cylinder through the priming cocks. 
The carburetor may also be heated by the application of warm cloths. 
The priming gasoline can be heated to advantage by placing a bottle of it 
in a pan of hot water. 

(0) Frozen Carburetor. If there is water in the gasoline this water 
may be frozen in the carburetor. The water, being heavier than the 
gasoline, sinks to the bottom where it may freeze in cold weather. To 
remedy this trouble apply hot cloths to the parts affected. Never use a 
torch or flame of any sort around the carburetor. 

(K) Feed System Stopped Up. If, after priming, the engine starts 
and suddenly dies down, the gasoline supply may be exhausted, the feed 
pipe may be clogged, or a piece of dirt may have worked into the needle 
valve. If there is a supply of gasoline and the trouble is found to be due 
to dirt in the feed system, the feed pipe may be disconnected and the dirt 
blown out. A particle of dirt in the needle valve may be removed by 
screwing the valve shut and then opening it the proper amount. This 
trouble and also the one due to water in the gasoline can be prevented by 
straining the gasoline through a chamois skin before putting it into the 
main tank. 

(1) Loss of Pressure on Gasoline Tank. It sometimes happens that 
if a pressure gasoline system is used, the pressure becomes too low to 
force the gasoline from the main tank to the auxiliary tank. This causes 
a lack of fuel at the carburetor. A hand pump is usually furnished for 
increasing this air pressure on the tank. 

If the car is equipped with a gravity feed system, the gasoline may fail 
to run to the carburetor when ascending a steep hill. It sometimes be- 
comes necessary to back the car uphill, in which case the gasoline will 
run to the carburetor without difficulty. 

(j) Water Logged Carburetor. It sometimes happens that the carbu- 
retor becomes loaded with water, due to the fact that it can neither evapo- 
rate nor get out. This water prevents the gasoline from getting in. 
The water should be drained from the carburetor drain cock. 

155. Ignition Troubles. (a) Locating Defective Plug. If one of the 
cylinders is missing at all speeds, the ignition is at fault. The cylinder 
can be located by opening the priming cocks and watching for the flame 
to come out. The cylinder without flame, out of which issues only a 
hiss, but no short report, is the one at fault. All of the plugs can be taken 
out of the cylinders and, with the wires attached, placed on the cylinder 
so that the threaded portions only are in contact. By turning the engine 
over, the defective plug can be detected. 

(fo) Defective Plugs. A defective plug may be broken, oil soaked, 
carbonized, or the air gap between terminals too much or too little. 
If the plug is broken, it usually must be replaced by a new plug. A plug 


with a loose center electrode may sometimes be repaired. If carbonized 
or sooted up, the plug may readily be cleaned with a stiff brush and gaso- 
line. Do not scrape with a knife, as it merely rubs the carbon into the 
surface of the porcelain. 

The gap between plug terminals should be between >^ and % 2 in. 
It should not be more or less than this amount for efficient ignition. A 
smooth dime is a good gage to use for setting this gap. 

(c) Locating a Missing Cylinder. If, after the plugs are found to be 
in good order, one or more of the cylinders miss, the ones at fault can be 
located by detaching the wire from the plug and holding the end about 
34 in. from the plug binding post. A missing cylinder will show no spark, 
and the trouble is due to a lack of secondary current in the wire to the 
plug. Instead of detaching the wire from the plug, the current can be 
short-circuited by placing the metallic part of a screw-driver in contact 
with the plug binding post with the tip of the screw-driver about 
J4 m - from the metal of the cylinder. As before, the missing cylinder 
will show no spark. Lack of current at the plug may be due to defective 
wiring, weak or run down batteries, poor adjustment of vibrator or 
circuit breaker, engine out of time, and dirty or defective magneto 

(d) Defective Wiring and Switches. If there is no current at the 
plug, the wiring system should be examined carefully for dirty and 
loose terminals, broken connections, and oil soaked and wet wiring. 
If the insulation has been worn off, the current is liable to be short-cir- 
cuited or grounded through the engine or frame of the car. Defective 
or poor contacts at switches may also be the cause of no current at the 

(e) Dry Batteries. Weak or exhausted batteries are a common source 
of trouble. If the batteries are suspected, they should be tested with a 
small "ammeter." If any one of the dry cells shows less than 6 amp., 
it should be taken out and replaced with a new one. One weak cell will 
greatly interfere with the operation of the others in the set. Occasionally, 
a weak dry cell can be livened up temporarily by boring a small hole 
through the top and pouring in a small quantity of water, or better still, 
of vinegar. The effect is, however, only a temporary one. 

Dry batteries should always be kept perfectly dry. If they become wet 
on the outside, there is a tendency for the battery to be short-circuited 
and exhaust itself. Especially is this true if water spills on the top of 
the battery between the terminals. 

(/) Storage Batteries. If the storage battery appears dead or shows 
lack of energy, it may be due to one of the following causes of trouble: 
(a) discharged; (6) electrolyte in the jar too low; (c) specific gravity of 
electrolyte too low; or (d) plates sulphated. These troubles are fully 


treated in the chapter on starting and lighting under the heading of 
Storage Batteries. 

(g) Magneto Troubles. If the ignition trouble has been located in the 
magneto side of the system and the plugs and wiring system have been 
found in good working order, attention should be turned to the magneto 
itself. The distributor plate should be thoroughly cleaned with gaso- 
line to remove any foreign matter which may have collected after con- 
siderable use. After attending to this, it should be determined whether 
or not the magneto is generating current. This can be done by dis- 
connecting the magneto cables and watching the safety spark gap while 
cranking the engine. If no spark appears there the trouble is in the 
magneto itself. 

The contact points may be pitted or burned. They should be filed 
until they meet each other squarely. Be sure that the adjustment is prop- 
erly made. 

The carbon or collector brushes may be dirty or worn. They should 
be cleaned, or if badly worn replaced with new brushes. 

It occasionally happens that the magnets become weak or demagne- 
tized. They may possibly be placed in the magneto in the wrong position. 
If weak or demagnetized, they should be remagnetized before being re- 
placed. Care should be exercised in getting the like poles of the magnets 
together on the same side of the magneto. Most magnets are marked 
with an "N" indicating the north pole. 

(h) Coil Adjustments. A frequent cause of no current at the plug is 
coil trouble, especially where a vibrating coil is used for each cylinder. 
The vibrator points become pitted, out of line, and burned, making good 
contact impossible. The tension on the vibrator spring becomes changed, 
permitting the coil to consume too much or too little current. 

In the case of burned or pitted points, they should be filed flat with a 
thin smooth file, or hammered flat with a small hammer. In either case 
the points should be so shaped as to meet each other squarely. 

If it becomes necessary to adjust the tension on the vibrators, the ten- 
sion should be entirely taken off and gradually increased until the engine 
runs satisfactorily without missing. It is very important to have all the 
units adjusted alike. This can be easily done after a little experience. 
The most accurate method of coil adjustment is with a coil current indi- 
cator by which the amount of current consumed is measured. Coils 
are built to consume about % amp. and the tension should be adjusted so 
that the current consumption of each coil is not much greater than this 

(i) Defective Condenser. A sparking between the points of a vibrating 
coil is due to dirty or pitted points, loose condenser connections, or a de- 
fective condenser. If the latter, a new unit must be supplied, 


(j) Breakdown of Wires or Insulation. If no current is obtained in the 
secondary of a coil, when the vibrator is working as it should, the trouble 
is probably due to a broken wire inside of the coil. It sometimes happens 
that the binding post wires become loose from the post just inside of the 
coil. If only a slight spark can be obtained, the insulation on the inside 
wire may be broken down, thus causing a short circuit of the current. 
Obviously there is no remedy but to replace the coil. 

(k) Timers and Commutators. Trouble in the timer or commutator 
usually comes from oil, water, and dirt which has found its way inside of 
the housing, causing a short circuit. This foreign matter should be 
cleaned out of the timer in order to have it give good service. After a 
time, the contact points in the timer become worn and loose. New points 
should be put in and all loose parts tightened. If the lost motion becomes 
too great, it may be necessary to supply a new timer. 

(1) The Spark Setting. If the engine kicks back after cranking, the 
spark is too far advanced an.d should be retarded so that the spark does 
not occur until the piston has passed the dead center. The tendency of 
an early spark on starting is to cause the engine to start backward. Too 
early a spark at slow speeds will make the engine knock and will cause the 
car to jerk. 

A retarded spark causes the engine to overheat and lose considerable 
of its power. There is no advantage of retarding the spark past center, 
even in starting. When running it should be advanced in proportion to 
the speed. , 

On cars equipped with automatic spark advance, the troubles due to 
early and late spark are not experienced. Preignition from other causes, 
however, may occur with either type of spark advance. 

(m) Premature Ignition. Premature ignition is caused by particles of 
carbon, sharp corners, etc., becoming incandescent from the heat of ex- 
plosion and igniting the charge on the compression stroke before the spark 
occurs. Premature ignition occurs generally when the engine has been 
loaded quite heavily at a slow speed, as when going up a steep hill on high 
speed. Any engine will have premature ignition if it becomes excessively 
hot under low speed and heavy load, but the tendency to preignite is much 
more marked if the cylinder is full of carbon deposits. These carbon de- 
posits should be cleaned out as explained before. 

156. Lubricating and Cooling Troubles. (a) Engine Lubrication. 
The usual lubricating troubles are those due to the use of the wrong kind 
of lubricating oil or too much or too little of it. An engine with loose 
fitting pistons requires a heavier oil than one with tight fitting pistons, and 
an air-cooled engine usually requires a heavier oil than a water-cooled 
engine. It is very essential that a true gas engine cylinder oil be used for 
cylinder lubrication because it alone satisfies the requirements. Poor 


lubricating oil is expensive at any price and it is good economy to use the 
best cylinder oil obtainable. In this matter the recommendations of the 
manufacturer should be followed out. 

An excess of lubricating oil shows itself by a white bluish smoke com- 
ing from the muffler. In addition to this, an excess of lubricating oil 
causes the formation of a pasty carbon deposit in the cylinder, which causes 
the engine to overheat. 

The important things to look after are to be sure that there is a sufficient 
supply of oil and that the oil pump is in working order. The crank case 
should be drained and washed out with kerosene and new oil put in every 
1000 miles. 

(6) Poor Circulation. Poor circulation in the cooling system is one of 
the common sources of trouble and when neglected is liable to give the 
motorist many uneasy moments. The water system must be kept filled 
with water. This is of especial importance in the thermo-syphon 
system, in which the water level must at all times be above the return 
pipe from the engine to the radiator in order to have the circulation 

A worn pump may cause poor circulation, because in most cases the 
thermo-syphon effect in a forced system of circulation is not enough to 
keep the water moving at the proper rate. 

Sediment in the radiator and scale in the engine jacket may seriously 
interfere with the circulation of the water. Such clogging of the system 
comes from the continual heating and cooling of the impure water used. 
This emphasizes the desirability of using pure water or rain water in the 
radiator. The sediment and hard scale may be removed as follows: 
Open the drain cock in the bottom of the radiator and introduce the end 
of a hose in the filler of the radiator. Run the motor for about 15 minutes 
and the fresh water from the hose will clean out the loose sediment or 
scale in the water jackets and radiator. Through this process, a supply 
of fresh water is constantly entering the system and passing through the 
water jackets while the motor is running. 

Next, dissolve as much ordinary washing soda as can be dissolved in 
enough water to fill the radiator. Then run the motor with a retarded 
spark until the water is brought up to the boiling point. Allow this solu- 
tion to remain in the motor and radiator for several hours, after which 
again open the drain cock and, with a hose, again flush out the entire 
system with fresh water as before. In extreme cases it would be well 
to repeat this process several times. The final operation of flushing out 
with fresh water should be thoroughly done. If any of the washing soda 
solution is left in the motor or radiator, it may result in undesirable 
chemical action. 

When rubber hose forms a part of the circulating system, a kink or 


twist in the hose may possibly cause poor circulation of the water. The 
inside fibers of the hose also tend to come loose and clog the system. 

In the case of thermo-syphon cooling systems or in air-cooled motors, 
the operation of the fan is essential to the successful operation of the cool- 
ing system. If the fan belt breaks or slips, or the fan blades are bent, the 
air circulation through the radiator is interfered with and consequently 
the water is not properly cooled. 

The attention which must be given to the cooling system in winter to 
prevent freezing has been thoroughly taken up in Chap. V. One thing 
to be watched in winter running is the temperature of the water. If the 
weather is excessively cold, the water may be cooled below the efficient 
running temperature of from 180 to 200. In this case, the radiator 
front should be partially covered in order to keep out a part of the cold air. 
This will also keep the water warm for a longer time when the car is 

157. Starting and Lighting Troubles. The troubles ordinarily ex- 
perienced with the starting and lighting systems are taken up in the chap- 
ter treating of those subjects. 

158. Transmission Troubles. (a) Clutch Slips. Clutch troubles are 
about the same in either the cone, plate, or multiple-disc types. The 
clutch either slips, engages harshly, grabs, or refuses to release. If it 
slips, the full power of the engine is not transmitted and the clutch becomes 
hot from the friction. In the cone and dry-plate types, a coating of oil 
on the facings will cause slipping. The wear of the facing or weak or 
broken springs will cause the same results. If the slipping is caused by 
grease and dirt, the clutch leather should be thoroughly cleaned with a 
rag dipped in kerosene. 

(6) Clutch Grabs. If the clutch engages harshly or grabs suddenly, it 
may be due to the drying out or hardening of the clutch leathers. A dress- 
ing of the facing with neatsfoot oil or castor oil will make it soft and permit 
gradual engagement. If the clutch springs are too tight, the clutch will 
"drag" and burn the leather facing. 

If a multiple-disc or plate clutch is designed to work in an oil bath, it 
will engage harshly or grab if the plates become dry. The clutch will also 
fail to disengage when the pedal is pressed down. 

(c) Change Gears Stick. If the change gears stick when attempt is 
made to shift from one gear to another, the shifting members may be 
stuck on the shaft. If the gears have become burned or teeth broken out, 
the particles of metal may prevent the movement of the sliding member. 
Occasionally the shifting lever becomes stuck and refuses to operate the 
gears. Under ordinary conditions, the change gears should give very 
little trouble if due attention is given to the lubrication and care to their 
shifting in operation. 



(d) Differential Troubles. A noisy differential and driving gear is due 
to dirt, lack of grease, or broken or worn teeth. In some cases wear can 
be taken up by the proper adjustments, but these should always be made 
by an experienced mechanic. The differential, as a rule, will give very 
little trouble. A break in the differential or in its connections to the 
wheels is made evident by failure of the engine to propel the car. If the 
connection to either wheel is broken the other wheel will also lose its power. 

159. Chassis Troubles. (a) Faulty Alignment of Front Wheels. Most 
of the front wheel trouble is due to faulty alignment. The following 
instructions are given for the adjustment of the front wheels and bearings 
on the Overland car: The front wheels, when correctly aligned, are not 
exactly parallel, but "toed-in" (Fig. 242). To test their proper align- 
ment, jack up both front wheels and with a piece of chalk or a lead pencil 

FIG. 242. Toed-in and cambered front wheels. 

held in a fixed position against the tire spin the wheels, drawing a line 
around the tire casing. The distance between the lines measured at the 
front of the wheels should be from % to ^ in. less than in the rear. 

"If a steering knuckle is bent, it is best to replace it with a new one, 
because bending it cold will not always restore its correct shape, while 
heating it may make it too soft for safety. 

"If faulty alignment is due to a bent steering cross-rod, it may be 
straightened out and then adjusted by loosening the lock-nut and screw- 
ing the rod in or out of its yoke end. Be sure to lock the nut tightly 
after adjusting. 

"The front wheels are also 'set,' or 'cambered/ so that the wheels are a 
little closer together at the bottom than at the top. This arrangement is 
desirable on account of the fact that the front wheels are 'dished' so as to 
make the wheel a sort of flattened cone. This 'dish' of the wheel is com- 
pensated by the 'camber/ by which means the lowest wheel spoke is in a 
vertical position with relation to the road surface. The combined 'toe- 
ing-in r and 'cambering' makes for greater strength and also reduces mate- 
rially the effort required in steering the vehicle. The camber is sequred by 
inclining the axle spindle from its central line, and no adjustment is re- 
quired in connection with it. 


"To see whether the front wheel bearings need adjustment, jack up 
the wheels. Any looseness will show on rocking the wheels sideways. 
To tighten the bearing, spin the wheel, at the same time screwing down the 
adjusting nut until the bearing is so tight that it will stop the rotation of 
the wheel. Then back off the nut only enough to allow the wheel to spin. 
Lock in this position and the bearing will give the best service. 

"In general, a somewhat loose bearing is to be preferred to one that is 
so tight that the rollers are likely to become injured." 

(b) Loose Steering Gear. With continued use, the worm or screw in the 
steering gear will wear, and a looseness of the wheel will result. Means 
are usually provided for taking up this wear. Most drivers prefer to have 
a small amount of lost motion (about % in.) in the wheel, as it makes 
steering easier and relieves the steering gear from all the road shocks. 
A great deal of steering gear trouble and wear can be avoided by oiling 
all the joints regularly. This important point is too often neglected. 

(c) Brakes. It is very necessary that the brakes be kept in perfect 
working order at all times. It is more necessary to be able to stop the car 
in emergencies than to start it. If the brakes fail to hold, it may be that 
the drum and band facings have become covered with oil and dirt, or 
the band facings may be worn. In the latter case, new facings are neces- 
sary in most cases, but adjustments can be made for slight wear. 

The brakes may bind or stick, due to the tight adjustments. With 
tight adjustments, the motor is pulling the car against the friction of the 
brakes at all times. 

If the brakes are not adjusted the same on each side of the car, there 
will be a tendency for the car to skid when the brakes are applied. The 
braking effect comes on only one wheel and this tends to swing the car 
around. Many cars are provided with brake equalizers which allow 
them to work together. 

(d) Springs. After a car has been run for some little time, the spring 
clips become loose and the conditions are then ideal for breaking the 
springs. Spring breakage occurs mostly with loose clips. Consequently 
these clips should be tightened every once in a while. 

When springs are not lubricated, water works its way in between the 
leaves and causes them to rust, often to such an extent that they become 
almost like solid pieces. This causes them to lose much of their spring 
action. It is a good plan to jack up the frame of the car occasionally, 
so as to take the weight off the springs, and insert oil and graphite 
between the leaves. It is also a good plan, about once a year, to have 
all the springs taken apart, the surfaces thoroughly cleaned and coated 
with a thick mixture of oil and graphite. 


160. Preparations for Starting. Before starting an automobile en- 
gine, the driver should make sure that there is plenty of gasoline in the 
tank and that it is turned on so as to flow to the carburetor. The radiator 
should be filled with clean water, free from lime or other form of matter 
that will have a tendency to coat the inside of the radiator when the water 
evaporates and thus prevent cooling action. Rain water is best. The 
driver should also be sure that he has plenty of lubricating oil. In starting 
the engine, close the switch on the battery circuit, or, in some cases, where 
a high tension magneto is used, the engine may be started on the magneto. 
It is better, though, in most cases, to use the battery circuit, as the cur- 
rent there is always available. The change speed lever should be in the 
neutral position. If the lever is so that the gears are meshed, cranking the 
engine would start the car in motion, and engines that pick up easily are 
liable to start and run away, especially if the gear shift lever is in the first 
position. It is also advisable to have the emergency brake set. This 
will quite often prevent runaways. The spark lever should be retarded, 
and the throttle lever slightly advanced before cranking the engine. As 
soon as the motor starts, advance the spark lever about two-thirds of the 
distance around the quadrant, and retard the throttle lever so that the 
motor will not race. 

161. Cranking. In cranking the engine, always set the crank so as to 
pull up. In this manner, should there be a back-fire the crank will be 
pulled down out of the hand; whereas, if one is pushing down on the crank, 
the back-fire will be very liable to cause injury to the driver's wrist or arm, 
as he would be unable to get away from it. 

After an engine has been standing for some time, it is quite probable 
that it will not get gasoline at once, due to the gasoline evaporating or 
leaking from the carburetor. In order to have sufficient gasoline in the 
mixing chamber, it is customary to raise the float, which allows the gaso- 
line to overflow into the mixing chamber. This process is commonly 
called " priming" or "tickling" the carburetor and insures a rich mixture 
in starting. 

This may also be accomplished by opening the priming cocks on the 
cylinders and pouring a few drops of gasoline directly into the cylinders. 
If there are no priming cocks on the cylinders, one can use a priming spark 

25 231 


162. How to Drive. There is "good form" and "bad form" in driv- 
ing a car the same as in doing anything else. One-half the pleasure of 
motoring comes from knowing how to drive easily. Proper driving also 
means minimum strain and wear on the car. It prevents unnecessary 
stress and wear on the motor and transmission system, and saves the gaso- 
line and oil. In starting the automobile, the object is to have the car 
pass from a stationary position into rapid motion with the least amount 
of stress on the motor and transmission, and also with the most comfort 
to the occupants of the car. In doing this, a steady pull should be main- 
tained on the driving mechanism from the point where the driver lets in 
the first speed until the car is under full headway. Starting with a jerk, 

FIG. 243. Shifting gears. 

or passing unevenly from one speed to another, strains the motor, racks 
the frame, and causes various troubles in the driving mechanism. 
Having started the engine with the gears in the neutral position, the 
proper method of gear shifting is as follows: 

Advance the spark lever about two-thirds of the way around the 
quadrant, throw out the clutch, and throw the speed change lever in the 
first position, as shown in Fig. 243. Let the clutch in easily but firmly 
and increase the motor speed gradually, either by the foot accelerator or 
by the hand throttle, until the motor picks up the load. Try to acceler- 
ate the engine as the clutch is let in. The mechanical act of shifting gears 
is very simple, but the knack of learning to perform the operation rightly 
takes practice. As you engage the gears for any speed and begin to let in 
the clutch, give the motor more gas at the same time. Once you have 
learned to do this properly, you will never have to give it a thought. 



In changing from first to second speed, release your foot accelerator or 
throttle hand lever, then throw out the clutch, change to second speed, 
and again let in the clutch, at the same time accelerating the engine again. 
Repeat the same operation on going into higher speed. 

Just before shifting gears, the engine should be throttled by removing 
the foot from the accelerator, so that the two gears which are going to be 
meshed are running at the same speed. This permits a smooth shifting 
of gears, and also prevents the motor from racing. Then as the clutch is 
let in the engine should be accelerated to give it sufficient power. 

When the car is in high speed, assume a comfortable easy position. 
Do not sit sideways in the seat nor take your hands from the steering 
wheel. If one sits in an easy upright position, driving does not become 
tiresome, and it also gives a person better control, as he does not have to 
move from his position in order to operate any of the levers. Also, an 
erect and alert driver makes a better appearance than one who slouches 
in his seat and handles his car carelessly. 

FIG. 244. Emergency stop. 

163. Use of the Brakes. The operation of stopping a car smoothly is 
just as important as knowing how to start. The best results are obtained 
by beginning to pull up your car early enough, so as to apply your brakes 
gradually, thus bringing the car to a stop without straining the mechan- 
ism or jolting the passengers. Do not wait until you are within a few 
feet of the stopping place and then have to use the emergency brake or 
jam the brakes down hard. Applying the brakes hard is not only an 
unnecessary strain on the mechanism, but is very hard on tires since, 
when the wheels stop, the road acts as a file on the tires. 


Sometimes it is necessary to make an emergency or quick stop. In 
doing this the operator does not take time to slow down his engine, but 
presses both foot pedals and applies the hand emergency brake at the 
same time, as shown in Fig. 244. In pressing both pedals, he releases the 
clutch and applies the service brake, and the braking effort is further 
increased by the application of the emergency brake. 

In descending steep hills, it is often convenient to use the engine as a 
brake. This can be done by closing the throttle and shutting off the 
spark. Then by leaving the clutch in, the car is forced to run the engine 
against compression without receiving any power from it. The gear 
shift lever may be left in either high, intermediate, or low speed. In the 
low speed position the engine will have more of a braking effect than in the 
high speed position, because it must be turned much faster for the same 
speed of the car. If the grade is long and steep, use the foot and emer- 
gency brakes alternately. This equalizes the wear on them. 

164. Speeding. When running a new car, do not speed it up until 
you are absolutely sure of your ability to drive. Furthermore, any new 
piece of machinery should not be run at high speed for any length of 
time until its bearings have had a chance to wear to a smooth fit. A few 
miles of racing are harder on the bearings of a car than several days of 
moderate driving. 

165. Care in Driving. All cars have low and intermediate gears for 
use in starting, hill climbing, and bad roads. A good rule to follow in 
shifting gears is to shift just before you need to in climbing hills. To 
attempt to climb every hill on high speed always marks the amateur 
driver. The intermediate gears should be used on steep hills, even if they 
could be climbed on high speed. If it is desired to climb a hill on high 
speed, one should take a running start and rush up the hill. In going over 
bad roads, it is better to shift into second or first speeds immediately. 
This will save slipping the clutch, which is a bad practice. On the 
lower speeds, one can control the speed of the car entirely by the use of 
the throttle. 

In going over bridges, cross-walks, railroad tracks, or water-brakes, it 
is better to strike them- at an angle than to hit them squarely. This 
method throws the strain on the springs successively instead of all at 
once and reduces the rebound of the car. In going through sand, it is 
better to let the car pick its way and not try to hold it in line and force it 
to make a new track. For this reason a little play in the steering gear is 

One of the first things that a new driver learns is the advantage to be 
derived from consideration and courtesy extended to others using the 
public highway. Most drivers know that they are expected to turn to the 
right when approaching a vehicle, or to the left in overtaking and passing 


a slow-moving vehicle going in the same direction. In meeting another 
car at night, dim your headlights so that they will not confuse the other 

After they have begun to realize the accuracy with which a car 
may be steered and the ease with which it may be called upon to pass 
another vehicle, possibly approaching from the opposite direction, it 
seems natural for some drivers to display their nerve in not turning from 
the center of the road until they are almost upon the approaching vehicle. 
Often, however, the other fellow has as much courage and takes the same 
stand, and in the confusion which very frequently follows, either one or 
both cars are damaged on account of collision. 

In passing vehicles which are approaching, as large a margin of space 
as possible should be afforded, and in passing a slow-moving vehicle 
ahead, pass it as quickly as possible and without cutting in short ahead 
of it. 

166. Driving in City Traffic. The lack of consideration on the part of 
a few careless drivers has resulted in the adoption of very strict muni- 
cipal regulation governing traffic. Those who are familiar with city 
traffic regulations and apply them as well on country roads, will not be 
likely to encounter difficulties. 

The burning of at least three lamps, including two head or side and one 
tail lamp, is enforced from sun-down to sun-up in practically every state. 

FIG. 245. Turning to the right. FIG. 246. Turning to the left. 

In approaching an intersection, either in the city or in the country, 
where a clear vision of the road approached can not be had because of 
buildings, fences, etc., which obstruct the view, the car should be slowed 
down to a speed at which it can be readily stopped in case of the approach 
of another vehicle from either side. 

In turning into another road to the right, the driver should keep his 
car as near the right-hand curb as practicable, as shown in Fig. 245. 

In turning into another road to the left he should turn around the 
center of the two and as in Fig. 246. No vehicle should be slowed or 
stopped without the driver thereof giving those behind him warning of his 
intentions to so do, by proper signals. 

Often drivers of horse-drawn vehicles become confused if their horses 
are frightened by the approach of an automobile and in drawing up the 


horses sharply to one side the animals are liable to jump or rear, with the 
result that the vehicle may be overturned and the automobile injured as 
well. In cases of this kind, it is better to stop the machine entirely and, 
if necessary, even stop the motor. 

More accidents result from unwillingness to change gears than from 
almost any other cause. Most American drivers use their first and sec- 
ond speeds only in starting their car. They allow the car to drift along 
and thus get into a tight place in traffic or too close to street cars and, be- 
cause of misjudging the speed of the approaching vehicle or their selfish 
desire to crowd out another car, collisions or other accidents frequently 
result. It is a simple operation to change from third to second speed. 
It increases the power and affords the possibility of a great deal quicker 
acceleration as well. The second speed is incorporated for a purpose. 
It is seldom that we are in such a hurry that we can not spare a moment to 
afford absolute safety. 

Accidents are not due to one's losing control of the car in many 
instances, but are more likely due to one's losing control of himself. 
One is not an expert driver until he intuitively performs the operations 
which control the car just as one walks or reaches out for an object. 

167. Skidding. When traveling on slippery roads, avoid making 
sudden turns; also avoid sudden application of the brakes or sudden 
changes of power, as they all tend to cause skidding. 

Most skids can be corrected by the manipulation of the steering and 
brakes. An expert driver can keep his car straight under almost any 
conditions, but it is impossible to explain just how he does it, except that 
he knows his car and becomes almost a part of it. Usually the rear end 
skids first, and in the right hand direction, this being caused by the crown 
of the road. Under such conditions, the skidding action will be aggra- 
vated if the brakes are applied, and the car may be ditched or continue 
to skid until it hits the curb. 

The correct action in an emergency of this kind is to let up on the 
accelerator pedal and thus to reduce the power to a point where the wheels 
are rolling freely without either being retarded by the brakes or drawn 
ahead by the engine. If the car recovers its traction, the power may be 
applied gradually and it will be advisable to steer for the center of the 
road again. However, if the car continues to skid sideways, steer for the 
center of the road, applying the power gently. This will aggravate the 
skid for the moment, but will leave you with the front wheels in the center 
of the road and the car pointing at an angle. By so doing, you can 
mount to the crown of the road again and the momentum of the car will 
take the rear wheels out of the ditch on the right hand side. It is cus- 
tomary to advise turning the front wheels in the direction that the car is 
skidding in order to correct the action, but this can hardly be said to be 


advisable in most cases, as the amount of room on the skidding side is 
somewhat limited, and for this reason the explanation given above will 
better apply to such a condition. 

When turning a corner on wet asphalt pavements it frequently occurs 
that the front wheels skid. In a case of this kind, immediate action is 
necessary. It will be found that by applying the brakes suddenly for a 
moment so as to lock the wheels, the rear end of the car will skid in the 
direction in which the car is to be turned. This will help the action of 
the front wheels and the releasing of the brakes and the touch of the 
accelerator will bring the car around the corner without any over-travel 
of the front end. By applying the brakes in this way, it is possible to 
turn the front wheels in the direction opposite to that which the car is 
to be turned for a moment while the rear end is skidding. When the 
brakes are released, it is plain to see that the front wheels will have no 
tendency to skid farther, as they will be pointing in the direction which 
the car is to be turned and the rear end will be in line with it, due to 
the skid. 

Needless to say, this manipulation requires a little more expertness 
than the correction of an ordinary skid on a straight road. 

Skidding can be prevented and accidents avoided, also the life of 
the tires lengthened, if one will learn how to turn his car out of street 
car tracks and ruts. Make a sharp turn of the front wheels. Do not 
allow the wheel to climb along the edge of the rut and finally jump off 
suddenly, and do not attempt to climb out of these conditions at speed. 

Driving a car around a sharp corner at 25 miles an hour does more 
damage to the tires than 15 or 20 miles of straight road work. This is 
an economical reason why one should drive around corners cautiously 
and slowly. The other reasons are obvious. 

The natural inclination of the driver is to throw out the clutch in 
coasting down hill or driving over rough roads. This should not be done. 
Keep the motor pulling the car over rough roads. Thus it keeps every- 
thing taut and lessens the shock and jar that the car gets through 
bumping over ruts. 

168. Knowing the Car. One will very soon become accustomed to 
all of the noises the car makes, and any strange sound, be it ever so slight, 
will be immediately perceptible. 

Much of the satisfaction that an automobile gives depends upon the 
driver. If he neglects his automobile, if he does not lubricate it, or if 
he tinkers with it too much, he is bound to receive unsatisfactory 

No machine can be absolutely automatic. All things must wear in 
time. The best preventive of wear, and the most certain thing to increase 
the life of an automobile, is proper lubrication. Remember that a motor 


car is like any piece of machinery and will not keep in good running con- 
dition without a reasonable amount of care. The life of a car can be cut 
in two by neglect or doubled by careful use. 

One should familiarize himself thoroughly with all the lubricating 
points of the car. The chart in Chap. V will show where each one is lo- 
cated. Make the lubrication of the car as regular as the eating of meals. 
If one does this he will not have any complaint to make of his car becom- 
ing noisy or of bearings wearing out. If he does not do it, he will not get 
the satisfaction from his car that he expects. Satisfaction would be 
greatly increased if everyone would learn the details of his machine, that is, 
learn to make the simple examinations and adjustments. Do not depend 
on some one else to do that which is so simply done and which one can get 
much satisfaction in doing. One should familiarize himself with every 
detail of his car and then he will have great confidence in venturing over 
any road at any distance from a repair station. 

In learning to drive a car, it is better to use the hand throttle for the 
first few days until you have mastered the other details of driving. Then 
learn the use of the foot accelerator. The foot accelerator is controlled 
by a spring and is released by removing the foot. This will slow down the 
car to the point where the hand throttle is set. In using the foot 
accelerator, keep the hand throttle set at a point where the engine 
will just pull the car. Then, when the foot is removed from the 
accelerator, there will be no danger of an accident from the car's not 
slowing down. 

Never allow the motor to race when it is idle. "When there is no load 
on the engine it will vibrate unduly at high speeds, which causes exces- 
sive strains and makes the engine and car noisy. Racing the motor 
when driving can be avoided by learning to use the foot accelerator in the 
proper manner in relation to the clutch and gear shifts. 

169. The Spring Overhauling. The greatest trouble with the average 
motorist is that he has the idea that all the attention a car needs is to 
keep it full of gasoline, oil, and water. There are many owners, however, 
who enjoy making their own adjustments and keeping their car always 
in good condition by giving it frequent attention. After a car has been 
laid up for some time the oil is forced out of the bearings and, if run in 
this condition, considerable damage is liable to result. All old oil should 
be drained off and the case thoroughly washed out with kerosene. Hot 
kerosene and oil should be poured into the cylinders to cut the gummed 
oil and to remove any rust that may have formed. After draining off 
the kerosene, the crank case should be filled with oil to the upper test 
cock. Do not use the electric starter until you are sure that the motor 
is free to turn. Better turn the motor over a few times with the hand 
crank first. Clean the spark plugs by washing with gasoline and a 


brush never scrape them, then adjust the spark gap between points 
to about 3^2 in. or the thickness of a well worn dime. 

Test for leaks around the valves and spark plugs by squirting oil on 
the joints and then turning the engine over. If there are any leaks, air 
bubbles will be seen in the oil. 

If the gasoline does not flow to the carburetor, remove the feed pipe 
and blow it out; also clean the screen in the bottom of the carburetor. 
The gasoline flow can be tested by holding down the float. 

In the wet type multiple-disc clutches, the oil should be drained off 
and then they should be filled with kerosene. Replace the plug and 
start up the motor. Let the motor run for a few minutes during which 
time push the clutch in and out several times. Then stop the motor, 
drain off the kerosene, and fill with the proper amount of lubricant. The 
transmission, differential, and universal joint should also be washed out 
and repacked. Every point mentioned on the lubrication chart of 
Chap. V should be cleaned, adjusted and oiled. 

Electrical System. Remove the rotor and clean its bearings with gaso- 
line and a cloth, then rub a little vaseline on the race very lightly. Clean 
the breaker points with a fine piece of emery cloth and set the gap to the 
width of the gauge, or about ^4 in. See that all wiring connections are 
tight and free from corrosion. It is a good plan also to put in new dry 
cells and be sure that they are connected up properly. 

The storage battery is probably the most delicate part of the car and 
should receive very careful attention. It is advisable to give the battery 
a long overcharge at the beginning of the season, especially if the car has 
been laid up for some time. 

During the out-of-season period, rust will accumulate in the radiator 
and engine jacket, and should be cleaned out. To do this, drain out the 
anti-freezing solution and fill the radiator with a solution of soda and 
water. With this solution in the cooling system, run the motor for about 
10 minutes and wash out the system, following the instructions of Art. 
156(6), Chap. IX. 

The leaves of the springs should be spread apart and a mixture of oil 
and graphite inserted. 

If the tires have been removed for storage, see that a thorough appli- 
cation of soapstone is applied to the inside of the rims to prevent their 
sticking to the tires. 

An easy way to calculate pressure for tires is to multiply the diameter 
of the tire in inches by 20. For example, the correct pressure for a 3-in. 
tire is 60 lb., and for a 4-in. tire, 80 Ib. A tire should be pumped up till it 
becomes perfectly round when supporting the weight of the car. Of 
course the only sure way of getting the correct pressure is with the use of 
a reliable pressure gauge. 


170. Washing the Car. The car should be washed before the mud has 
a chance to dry. If a hose is used, the stream should be tempered or, 
better still, the nozzle should be taken off the hose and a slow stream 
used. Always use cold water, as warm water will injure the varnish. 
After hosing off the mud, take a sponge well filled with water and gently 
dash it against the surface. Never rub the surface when washing, as it is 
sure to scratch the polished surface. 

After the mud has been removed, remove any grease from the finish by 
washing with suds of a pure white soap. This should be done with a 
soft sponge and as little rubbing as possible. After soaping, rinse with 
cold water, rub dry, and polish with a chamois skin. Do not have the 
car standing in the bright sunlight, for it will dry too rapidly and be 

A new car should be washed with cold water before it gets dirty. The 
cold water will help to set the varnish and prevent the accumulation of 

Cleaning the Reflectors. When lamp reflectors become dirty do not 
wipe them, but use a stream of cold water to remove the dust or dirt 
and permit the reflectors to dry by air only. The reflectors are silver 
plated. The silver becomes scratched when the reflector is wiped, even 
with very soft material. If reflectors become dull after long service, they 
should be polished by using chamois with a light application of red rouge 
or crocus. The chamois should be very soft and free from wrinkles. If 
a wad of cotton or waste (about the size of an egg) is placed within the 
chamois, a smooth surface for wiping can be obtained. Red rouge or 
crocus is used by j ewelers for cleaning watch-cases. When properly placed 
on chamois, it will not scratch the reflector. Moisten the chamois 
with alcohol, then apply the rouge or crocus to the chamois and wipe the 
reflector with a continuous rotary motion, but do not press too hard. 
The polishing marks will be very noticeable if other than a rotary motion 
is used. The efficiency of old reflectors will be increased if they are silver 
plated. This should be done by a lamp manufacturer or a reliable 

171. Care of Tires. The following few suggestions will apply to 
pneumatic tires in general. The various sizes of tires are constructed 
for the purpose of carrying up to certain maximum loads and no more. 
Owners should realize, therefore, that overloading a car beyond 
the intended carrying capacity of the tires is sure to materially shorten 
their life. 

Do not turn corners or run over sharp obstructions, like car tracks, 
at a high rate of speed. Such practice is sure to strain or possibly 
break the fabric, with the result that the further life of the tires will be 


limited. Remember that most tire troubles are the result of abuse more 
than use. 

In case of puncture the car should be stopped at once and the tube 
repaired or replaced. The tire should also be examined carefully and the 
cause of the puncture ascertained, and the nail, glass, or whatever it may 
be, should be extracted. Before replacing the tire on the wheel, examine 
the inside of the casing to see that the cause of the puncture is not still 
protruding, because, if allowed to remain, it would continue to cut the 
inner tube. It is also advisable to look over the outside of your tires fre- 
quently and take out any pieces of glass or other particles which may 
have become imbedded in the casing, as they are liable to work themselves 
in and finally puncture the inner tube. 

A puncture, gash, or cut sufficiently deep to expose the fabric should 
have a vulcanized repair made without delay. Otherwise, water and dirt 
will soon ruin the whole tire, the threads acting as a conductor for the 
moisture, the fabric thus becoming rotted. 

A bruise is an injury to the carcass of a tire caused by violent contact 
with an irregularity which tears the fabric. Usually the injury does not 
show at once. However, the structure of the tire is permanently weak- 
ened at the injured spot, and eventually a blowout will occur. Even 
the most careful and skillful driver cannot avoid bruises altogether. But 
if your tires are properly inflated and you strike an obstruction, the tire 
has the resiliency of the air behind it to aid in resisting the impact of the 
blow and the effect is likely to be less serious. 

Experience has taught the careful driver to carry one or more spare 
tubes, as a cemented roadside repair will not always hold, especially in 
warm weather, as the heat generated in the tire may loosen the patch. 
When touring, a spare casing should always be carried. It should be 
strapped tightly to the tire holder, otherwise it will chafe. 

Spare tubes should be kept lightly inflated. This keeps them in good 
condition and prolongs their life. They should not be stored in a greasy 
tool-box under any circumstances. 

Excessive weight on a casing will break down the fabric in the side 
walls, and if persisted in, a blow-out is apt to result. When this occurs, 
the casing is likely to be so badly damaged as to be beyond repair. If 
your roads are very rough and stony, or if you are carrying heavy weights 
in your car, it is better to equip the car with a set of extra-size tires. 
You can get larger tires which will fit your rims. 

Pneumatic tires are designed to carry loads in proportion to their cross- 
sectional area and diameter. They should never be overloaded. Fol- 
lowing is given a table of the various tire sizes and the weight each tire 
should carry. Weigh the car, and if the tires are carrying more than 
their rated load put on larger tires. 



Size of tires 

Load per wheel in 

Size of tires 

Load per wheel in 

2^ in. all diam. 


30 X 4 in. 


3 in. all diam. 


32 X 4 in. 


28 X 3M in. 


34 X 4 in. 


30 X 3K in. 


36 X 4 in. 


32 X 3^ in- 


32 X 4K in. 


34 X 3^ in- 


34 X 4H in- 


36 X 3^ in. 


36 X 4^ in. 


All 5 in. 

1000 or over. 

If the car is not used during the winter, it is better to remove the tires 
from the rims, keeping casings and tubes in a fairly warm atmosphere 
away from the light. It will be better to slightly inflate the tubes, as 
that keeps them very nearly in the position in which they will be used later 
on. Before the tires are put back, the rim should be thoroughly cleaned 
and any rust carefully removed; a coat of paint or shellac is also advised. 
If the tires are not removed and the car is stored in a light place, it 
will be well to cover the tires to protect them from the strong light, which 
has a deteriorating effect on rubber. 

The greatest injury that can be done to tires on a car stored for the 
winter is to allow the weight of the car to rest on the tires. The car 
should be blocked up, so that no weight is borne by the tires, and the 
tires should then be deflated partially. This will relieve the tires of all 
strain, so that in the spring they should be no worse for the winter's 

Extra casings carried on the car should be covered to protect them from 
the sunlight, which has an injurious effect on rubber. Do not place your 
extra tubes where they will come into contact with tools or oil. Carry 
the tubes in a tube bag. It is a good plan to tie a piece of cloth around 
the valve stem before placing the tube in the bag. This will prevent the 
possibility of the stem injuring the rubber. 

Bear in mind that heat, light, and oil are natural enemies of rubber. 
When grease comes into contact with your tires, it should be removed 
immediately with gasoline. 

Fast driving and tire economy have absolutely nothing in common. 
High speed and high bills for tire maintenance usually go hand in hand. 
It stands to reason that the wear and tear on tires is far greater when a car 
is driven at a high rate of speed than when it is used at a moderate pace. 
In addition to the increased force with which a wheel strikes an obstruc- 
tion, when rolling at an excessive speed, fast driving generates increased 
heat in your tires, causing disintegration. 

Shifting Tires Tires that show wear on one side from use on rutty 



roads or from driving in car tracks should be turned around. It is also 
a good plan to place the rear tires on the front wheels when they begin to 
show age. Rear tires carry more than half the weight of the car, get the 
roughest usage, and are also the driving tires, so that they naturally wear 
more rapidly than the front tires, which are simply subject to a rolling 
action and usually sustain less weight. A sprung axle will often cause 
quick wearing of a tire, for the reason that the tire is running at an angle 
with the direction of the car. This necessarily sets up a sliding and scrap- 
ing on the road surface. If the surface of one tire looks as if it has been 
sandpapered, examine the alignment of the wheels. 

FIG. 247. Broken fabric. 

172. Tire Troubles Broken Fabric. On the inside of the casing 
shown in Fig. 247 will be noticed a break in the fabric. This is the result 
of the blow received by the tire in hitting a stone, rail, or something of 
that sort at high speed. While no permanent mark may be left on the 
outside of the tire, especially if the object is smooth and blunt, the fabric 
inside may give way under the abnormal strain of such a blow. This does 
not indicate that the tire was in any way defective. 

Sometimes a tire may be run weeks after the fabric is broken from the 


bruise before the blowout occurs. It has even happened in a garage, with 
the car standing still. Sometimes the break will exist only in a few of the 
plies of fabric, which will pinch the inner tube, allowing the tire to deflate 

Blowouts. Few people realize the tremendous pressure tending to 
rupture a tire and the consequent great strength that must be given any 
repair that is to be effective. This is especially true in cases of blow- 
outs. Figure 248 shows a tire that has blown out due to ineffective repairs. 

FIG. 248. Blow-out from ineffective repairs. 

It originally had a small cut extending clear through the casing. An in- 
side patch, applied by the owner, did the tire more harm than good. The 
result, as shown in the picture, was that the pressure forced the patch 
through the hole, the patch wedging the fabric apart and causing it to 
break almost from bead to bead. The inside view shows how the patch 
has been pulled away from its original position and has been forced through 
the break. This condition results from the tire not receiving the proper 
attention when first cut. An inside protection patch, used with an out- 
side emergency band to take the strain at the weakened point, should be 
used until permanent repairs can be made. 



Skidding. Skidding, or sliding the wheels by too great a brake pres- 
sure, has a disastrous effect on tires. Dragging the wheels for even a 
short distance over a hard rough surface will grind off the tread and even 
go through several thicknesses of fabric. There is nothing to be gained 
by sliding the wheels. Learn to apply the brakes up to the point where 
the wheels will just turn and no farther. The braking effect will be just 
as great or even greater than if the wheels are skidded. 

FIG. 249. Rut-worn tire. 

FIG. 250. Tire injured by chains. 

Running in Ruts. No tire will stand the wear from continued running 
in car tracks or ruts. 

Figure 249 shows a tire worn off on the sides, commonly called "rut- 
worn." The same condition will result if a tire is run on muddy roads 
that have a frozen crust insufficient in thickness to support the car, so 
that the tire in breaking through is bound to be gouged off in the manner 
shown. This condition also results from running close to and rubbing 


against curbstones. A similar condition, but nearer the tread, is caused 
by running in car tracks. 

One can readily see that this puts the side of the tire to a greater test 
than its surface ever gets in merely passing over the road. No tire will 

withstand this rough treatment. 

Chain Bruises. Figure 250 shows a 
tire that has been injured by the use of 
chains. Almost any chain will injure 
a tire if used to excess, but some are 
more injurious than others. Evidently, 
the chain used on this tire was fastened 
to the spokes; at least, it appears that 
it was held tightly in one place, as the 
cutting appears at regular intervals. 
The tread is cut through the fabric 
and, in fact, loosened up and torn 
badly in places. The least injury re- 
sults from chains that are loosely ap- 
plied and have play enough to work 
themselves around the tire, distributing 
the strain to all points alike. The 
greatest amount of injury comes from 
using the chains on hard paved streets, 
where they are least needed. 

Poor Alignment. Figure 251 shows 
a tire that is worn to the fabric. This 
is a very common condition, and is 
caused by the wheels being run out of 
line and usually occurs on the front 
wheels, affecting both tires alike, 
although sometimes one tire only is 
affected. Improper adjustment of the 
steering apparatus, or a bent knuckle, 
cross-rod or axle is responsible. Under 
either of these conditions the tread will 
wear away in a remarkably short 

It is to be assumed that all cars are received from the manufacturer 
in perfect alignment, but after being run a while, the steering gear, if not 
watched very closely, is apt to become affected by wear or accident. To 
aid in steering, the front wheels are permitted to "toe in" just a little, 
but if allowed to do so to any marked degree, this condition is bound to 

FIG. 251. The 
result of poor 
wheel alignment. 

FIG. 252. Re- 
sult of under-in- 


Under-inflation. Figure 252 shows the result of running a tire under- 
inflated, that is, too soft. In this condition, the tire is being constantly 
kneaded by the road surface and the rubber is worked loose from its bond 
to the fabric. The wavy condition of the tread is due to this loosening. 
Another condition which is not visible in this figure is rim-cutting. There 
are probably more tires injured from this cause than any other. Proper 
inflation will prevent both conditions. There is a mistaken idea among 
many motorists that it is easier on tires if they are not inflated quite to 
the pressure recommended. Keep the pressures up to those recom- 
mended. There is little danger of over-inflation unless an air bottle is 
used. The prevailing pressure for tires is 20 Ib. times the diameter of 
the tire. For example, the pressure for a 4-in. tire is 20 times 4, or 80 Ib. 
Of course, the pressure should vary somewhat with the weight on each 
tire, but if a car is properly tired the above figures will hold. In the 
absence of any better test, a good rule to follow is to inflate to a sufficient 
pressure to prevent the tires from showing any depression under the 
weight of the car without passengers. 

Blisters. Small cuts in the rubber, especially if they extend to the 
fabric, should be given immediate attention. If these cuts are neglected, 
the tread will work loose from the fabric, sand will work in and form a 
sand blister. Furthermore, water reaches the fabric and quickly rots it 
so that a blow-out may soon result. As soon as discovered, such cuts 
should be cleaned out and the cut filled with some plastic tire compound 
made for this purpose. 

173. Figuring Speeds. In order to figure the speed of any automobile, 
it is necessary to know three things, namely: the speed of the engine in 
revolutions per minute, the gear ratio or gear reduction, and the size of 
the rear wheels. To make this figuring unnecessary the chart of Fig. 
253 has been produced, from which the result can be taken without any 
actual figuring. 

Thus, beginning at the bottom on the left hand side, the diameter of 
the wheels is 37 in.; follow vertically up the 37-in. line until it intersects 
the gear ratio diagonal. In this case the gear reduction is 3^ to I. The 
37-in. line intersects this diagonal at the point C. 

Then follow horizontally across to the right hand side of the chart, 
where such a horizontal line would intersect the diagonals representing 
the speed of the engine. In this instance the engine speed is taken at 
2000 r.p.m., and the line intersects it at the point D. From this point 
drop a vertical to the base, which will be intersected at a point represent- 
ing the car speed, in this case 67 miles per hour. 

The table can also be used to find the engine speed in revolutions per 
minute, knowing the car speed in miles per hour (which can be read on the 
speedometer}, the size of tires and the gear reduction. In such a case 




proceed as before, obtaining the horizontal line C-D extending across the 
diagram. Then starting on the right hand base line, at a point indicating 
the speed as 67 miles per hour, draw a line vertically upward until it 
intersects this C-D line. This point of intersection D will come on a 
diagonal, giving the speed of the motor. In this case it comes on the 
2000-r.p.m. line exactly, but if the speed were followed upward from 50 
miles per hour, for instance, another point would be obtained not on any 
of the curves drawn. However, it would be midway between 1600 and 
1400, so that 1500 r.p.m. would be taken as the motor speed. 

B.P.M. of Engine 

32 34 
Wheel diam. in inches 

100 90 80 70 60 50 40 30 20 10 
Oar speed. Miles per hour 

FIG. 253. Speed chart. 

174. Interstate Regulations. The lighting requirements of the 
different states are practically uniform and call for two white lights in 
front and one red light in the rear. It is usually required that the rear 
license tag be illuminated with a white ray from the rear lamp. Many 
cities now require that the headlights be dimmed. This makes it desir- 
able to inquire regarding such regulations before driving through a 
strange city. 

All states with the exception of Louisiana require the registration or 
licensing of automobiles in some form, but the law in Mississippi has 
been declared unconstitutional. The registrations are renewable an- 
nually except in the District of Columbia, Florida, South Carolina, Ten- 


nessee, Texas, and Utah, where they are perpetual, and in Minnesota, 
where they are for 3 years. Professional chauffeurs must be examined 
and licensed in nearly all states, while in some states even the owner and 
the members of his family must have drivers' licenses. 

Non-residents of a state are permitted to drive in most of the states 
for limited periods without taking out a license, providing they have 
complied with the laws of their own states and providing their own states 
reciprocate in this respect. These periods vary from 10 days in New 
Hampshire and Rhode Island to 90 days in California and Colorado and 
to unlimited periods of some others. 

In Oklahoma, South Carolina, Tennessee and Texas, non-residents 
are not exempt from registration, but the fee is only from 50 cents to 
$3 for these states. Oklahoma also permits its cities to license and 
regulate the use of automobiles. In Connecticut, non-residents are 
permitted to travel on their home licenses only provided they have two 
license tags, one front and one rear. In Louisiana, the entire control is 
left to the municipalities. 

In Alaska, there is no license required except for dealers. In Porto 
Rico, non-residents must secure a license from the Commissioner of 
the Interior. The fee is $2 per month. 

The motorist must remember that there are local restrictions every- 
where, which could not be given in the limited space available here, even 
if all of them were available. For instance, Wisconsin, Pennsylvania, 
New York City, Detroit, Chicago, Province of Ontario, etc., either require 
a full stop or slowing to 4 or 5 miles per hour in approaching a street car 
stopping to let off or take on passengers. These and local traffic police 
restrictions can be found out locally, or avoided entirely by driving slowly 
and carefully at all times, and in a manner consistent with the rights of 
others, particularly of pedestrians. 

In case of accident, the motorist should always stop, obtain the names 
of witnesses, and give his own name and other information freely, as well 
as evidence a willingness to assist, whether in the wrong or not. 

175. Canadian Regulations. Upon entering the Dominion, the 
owner or operator must give a bond for the re-exportation of the car. 
This is to prevent cars being taken in permanently duty-free. In the 
majority of provinces, a Dominion license and tags are necessary. 

If the tourist is not known personally to the officer at the border, he 
must take out the license and give the bond as mentioned above. But if 
known, he may be allowed to enter free of both duty and tax for 7 days. 

The bond given must be for twice the amount of duty, if the stay is 
to be for less than 6 months. This is furnished by bonding companies in 
the principal cities of the United States and Canada, and usually at the 
border line, the usual fee being $5. The following are among those 


who will furnish such a bond: Guarantee Co. of North America, 111 
Broadway, New York City; J. A. Newport & Co., Niagara Falls, Ontario; 
Niagara Falls Auto Transit Co., Niagara Falls, N. Y.; J. M. Duck, 
Windsor, Ontario; A. J. Chester, Sarnia, Ontario. Messrs. Newport and 
Duck will also procure the license and permit in advance, if requested, 
the charge being $4.30. 

176. Touring Helps Route Books. The whole of the United States 
and the tourable parts of Canada are covered by the Automobile Blue 
Books. Of these there are seven volumes, as follows: Vol. 1, New York 
State and Lower Canada; Vol. 2, New England and the Maritime Prov- 
inces of Canada; Vol. 3 ,New Jersey, Pennsylvania, Delaware, Maryland, 
and Southeastern States; Vol. 4, The Middle West to the Mississippi 
River; Vol. 5, The Far West from the Mississippi to the Pacific Coast; 
Vol. 6, California, Oregon, Washington, British Columbia; Vol. 7, the 
Metropolitan Guide. They are published by the Automobile Blue Book 
Publishing Co., 2160 Broadway, New York, and 910 S. Mich. Ave., 
Chicago, at $2.50 a volume. There are also other good route books pub- 
lished in different localities, among which is Kings Guide, which covers 
the north central states in great detail. This is issued by Sidney J. 
King, 626 S. Clark St., Chicago. 

For its members, the American Automobile Association maintains a 
route bureau and sells a number of excellent maps. 

For those who can use them, the topographical maps of the United 
States Geological Survey are most accurate and very interesting, giving 
more detailed information than any of the others, particularly with regard 
to difference of elevation. Information relative to them, prices, etc., 
may be obtained from the Director of the Survey, Washington. In 
some states, county highway maps may be secured from the state high- 
way department. 

177. Cost Records. It is always a good plan to know just what the 
operation of an automobile costs. The following forms are suggested for 
keeping data on which to base figures for the annual cost statement. 
These forms can be ruled on the pages of any notebook of about 5 in. by 
8 in. size. The notebook should be kept in the car so that complete 
records can always be made. In preparing an annual statement of the 
cost, it is customary to charge an annual depreciation of 20 per cent of 
the original cost of the car. The total cost for the year should include 
this depreciation charge, as well as the cost of gasoline, oil, tires, fines, 
and repairs. Accessories are more properly chargeable against the 
capital account of the car less an annual depreciation charge, the same as 
the car itself. The cost record will also give the owner a reliable record 
of the service obtained from his tires and the cost per mile. 





No. of 


Speedometer readings 

Notes on carburetor 


Total ga 

per gal., a 





Speedometer readings 

Brand of Oil 

Total ga 
Miles pe 

r gal., avj 





Serial No. Size- 

Date on 

Date off 

Speedometer Reading 

Front or Rear 








First Cost- 

Total Cost- 


Total Mileage- 
Cost per Mile- 

NOTE: Keep a separate sheet for each casing and tube. 










Total cost 



Name and Make 









Air cooling, 122 
Alcohol AS * fuel, TS 

heating value, 79 

xise in rs<iistor, 124 
Alignment of wheels, 246 
Alternating current, 127 
Ampere, definition of, 127 
Armature of magneto, 156 
At water Kent ignition, 141 
Automatic spark advance, 151 

Atwater Kent, 143 

Ddeo, 151 

Eisemann, 163 

Westinghouse, 146 
Axles, dead, 12 

front . 8 

live, 13, 71 

rear, 12, 71 


Batteries, dry, 128 

storage, 128, 182, 224 
Battery charging, 185 

connections, 129 

ignition, 130 

troubles, 224 
Bearing troubles, 221 
Bevel gear drive, 71 
Bloc cylinder castings, 55 
Blow-outs, tire, 244 
Bodies, types of, 2 
Bosch magneto, 167 

dual system, 170 

two-independent system, 173 
Brakes, 16 

troubles, 230 

use of, 233 
Buick oil pump, 108 

rear axle, 73 
Burton process, 76 

Cadillac cooling system, 121 

"wght ," engine, 60 

"four" engine, M 

oiling system, 111 
Calcium chloride, 124 
Cam angles, SO 

shafts, 58 

Canadian regulations, 249 
Carburetor adjustments, us 

principles, 79 

troubles, 221 
Carburetors, Carter, 97 

Holley, 86, 87 

Kingston, 90 

Marvel, 91 

Kay field, 95 

Schobler, 82, 84 

Stewart, 89 

Stromberg, 94 

Zenith, 94 
Cars, electric, 1 

gasoline, 2 

steam, 1 

types of, 2 

Cells (see "Batteries") 
Change gears, 66 
Charging batteries, 185 
Chassis, the, 2 

Ford, 48 

Hollier "eight," 47 

Mitchell "eight," 46 

Studobaker "six," 5, 45 

truck, 12 

Clearance and compression, 39 
Clutches, 64, 228 
Clutch troubles, 228 
Coils, vibrating, 132 

non-vibrating, 137, 156 
Cold test for oils, 104 
Commercial cars, 4 
Compression, 39, 216 




Condensers, 132, 225 
Connecticut ignition system, 139 

magneto, 160 
Carbon deposits, 220 
Control systems, 23 
Cooling the cylinders, 40, 117 

solutions, 123 

troubles, 227 
Cost records, 250 
Cranking, 231 
Crank shafts, 57 

Current, direct and alternating, 127 
Cycles, 25 

four-stroke, 26 

two-stroke, 35 
Cylinder cooling, 40, 117 

oils, 104 

Delco ignition, 147 

starter, 190 
Depreciation, 250 
Differential gear, 13 
Direct current, 127 
Disc clutch, 65 
Displacement, piston, 39 
Distributor system, 137 
Dixie magneto, 166 
Drive, final, 70 

-shaft, 69 
Driving, 232, 234 

in city, 235 
Dry battery, 128 

troubles, 224 
Dual ignition, 160 


Eclipse Bendix drive, 197, 203 
Eisemann magneto, 161 
Electrical definitions, 127 
Electric cars, 1 

ignition, 39, 127, 153 

starters, 181 
Electrolyte, 184 
En bloc cylinders, 55 
Engine, 25 

Buda, 52 

Cadillac, 51, 60 

Ford, 53 

Franklin, 56 

Engine, Jeffrey, 54 

tfnight, 33 

Mitchell, 55, 63 

Packard, 63 

Speedwell, 34 

Studebaker, 52 

troubles, 214, 216 

Wisconsin, 50 
Engines, eight cylinder, 60 

four cylinder, 50 

four-stroke, 26 

horse power of, 41 

six cylinder, 56 

twelve cylinder, 63 

two-stroke, 35 

Feed systems, gasoline, 99 

Fire test for oils, 104 

Firing order, four cylinder, 57 

eight cylinder, 62 

six cylinder, 58 
Flash point of oils, 104 
Flywheels, 38 
Force feed oiling, 111 
Ford chassis, 48 

control, 23 

cooling system, 119 

engine, 53 

lubrication, 106 

magneto, 174 

rear axle, 72 

timer, 135 

transmission, 69 
Four-stroke engine, 26 
Frames, 6 
Franklin, cooling, 122 

engine, 56 

frame, 6 
Friction, 103 
Fuels, 75 

Gasoline, 77 

heating value of, 79 

mixtures, 79 

records, 251 
Gear sets, sliding, 66 

location of, 44 

planetary, 67 
Glycerine for cooling, 124 



Gravity feed system, 99 
Gray and Davis starter, 193 
Grinding valves, 217 


Holley carburetors, 86, 87 
Hollier "eight" chassis, 47 
Horse power formulas, 41 
Hydrometer, battery, 184 
Baume", 77 

Ignition, 39 

systems, 127, 153 
troubles, 223 

Inductor magneto, 163 

Jesco starter, 205 

Mitchell "eight" chassis, 46 
engine, 63 

"six" engine, 56 
Mixtures, fuel, 79 
Mixture troubles, 222 
Motors (see "Engines") 

starting (see "Starters") 
Mufflers, 40 


Ohm, definition of, 127 
Oiling (see "Lubrication") 
Oil pumps, 106 

records, 251 
Oils, cylinder, 104 
Overhauling the car, 238 
Overland oiling, 109 

cooling, 118 

valve adjustment, 218 

Kerosene, 78 

heating value of, 79 
Kingston carburetor, 90 
Knight car, Lyons, 49 

engine, 34 

oiling, 113 
K-W magneto, 163 

master vibrator, 137 


Magneto, Bosch, 167 

Connecticut, 160 

definitions, 177 

Dixie, 166 

Eisemann, 161 

Ford, 174 

K-W, 163 

Remy, 157 

troubles, 225 
Magnetos, principles of, 155 

high and low tension, 156 
Magnets, 153 
Manifolds, intake, 102 
Marvel carburetor, 91 
Master vibrators, 136 
Mechanism of engines, 28 

Packard engine, 63 

Parallel battery connections, 129 

Petroleum, 75 

Pfanstiehl coils, 133 

master vibrator, 137 
Piston displacement, 39 
Planetary gear set, 66 
Plugs, spark, 135 
Power diagrams, 43 
Power, horse, 41 

plant and transmission, 14, 43 
troubles, 214 

plants, 50 

Pressure feed systems, 100 
Pressures, for tires, 247 


Rayfield carburetor, 95 
Rear axles, 12, 71 
Records, cost, 250 
Regulations, interstate, 248 

Canadian, 249 
Remy battery ignition, 149 

magneto, 157 
Repair records, 253 
Rims, 20 
Rittmann process, 76 


Rotary valves, 34 
Route books, 250 



Schebler carburetors, 82, 84 
Series battery connections, 129 
Shafts, cam, 58 

crank, 57 

drive, 69 

propeller, 69 
Silent Knight engine, 34 
Skidding, 236, 245 
Spark advance, 151 

Atwater Kent, 143 
Delco, 151 
Eisemann, 162 
Westinghouse, 146 

plugs, 135 

Speedometer drives, 21 
Speeds, figuring, 247 
Splash oiling system, 106 
Springs, 6 

care of, 230 
Starters, 180 

Delco, 190 

electric, 181 

Gray and Davis, 193 

Jesco, 205 

U. S. L., 204 

Wagner, 197 

Ward-Leonard, 187 

Westinghouse, 199, 200 
Starting in cold weather, 222 

generator troubles, 209 

motor troubles, 208 

on spark, 179 

system, care of, 207 
Steam cars, 1 
Steering gear, 10 
Stewart carburetor, 89 

vacuum feed system, 100 
Storage batteries, 128, 181 

battery, care of, 209 
in winter, 209 
troubles, 209, 224 
Stromberg carburetor, 94 
Strut rods, 16 
Studebaker chassis, 5, 45 

cooling, 119 

engine, 55 

gear set, 68 

Studebaker ignition, 149 
oiling, 119 
starter, 199 

Thermo-syphon cooling, 118 
Three point motor support, 44 
Time of spark, 151 
Timers, 135 
Timing, magneto, 176 
Tires, 19, 240 

pressures for, 247 

records, 252 

troubles, 243 
Torque arm, 15 

tube, 16 
Torsion rods, 16 
Transmission gears, 66 

location of, 44 

planetary, 66 

troubles, 228 
Troubles, 213 
Trucks, 4 
Two-stroke engines, 35 


Unisparker, 142 
Universal joints, 15, 69 
U. S. L. starter, 204 

Valves, 30 

adjustment of, 217 

arrangements of, 32 

grinding, 217 

rotary, 34 

timing, 29, 219 
Vaporization, principles of, 76 
Viscosity of oils, 104 
Volt, definition of, 127 
Voltage of dry cell, 128 

of spark, 132 

of storage cell, 129 


Wagner rectifier, 186 

starter, 197 
Ward-Leonard starter, 187 

INDEX 259 

Washing the car, 240 Wisconsin engines, 50 
Water cooling systems, 117 oiling system, 112 

Westinghouse ignition system, 144 Worm drive, 71 

starters, 199, 200 steering gear, 10 

Wheel alignment, 229, 246 
Wheels, 18 

Winter cooling solutions, 123 Zenith carburetor, 94 


Santa Barbara