Evening star. [volume] (Washington, D.C.) 1854-1972, 1920-08-01
Answers to Last Weeks Questions.

Answers to Last Weeks Questions.
knocks is difficult without previous
experience. Each part not adjusted
properly will give forth a sound diff
ferent from that of any other part,
and finding the particular sound is
not easy without the use of listening
devices or former training. To To-
cate a main bearing knock run the
engine on swo cylinders at a time,
operatjng One cylinder on each side
of a bearing The front bearing is
usually the last to become loose. Pay
at these points will produce hard
bump, caused by end play in the
crankshaft, loose, scored or burned
bearings Groaning of the motor
when it is first turned over is created
by the latter defect. A hollow. heavy
sound or a sharp bump comes from
a loose connecting rod. To locate
the rod, cut one cylinder at time
or, if very loose. can be found by
loose wrist pin in the piston Will
give a metallic knock. This loose
ness is caused by wear, crooheu
or broken pin or from TOO tisht II.
in the piston or connecting roo. speed
up the engine suddenly, then throttle
down quickly to locate the knock. A
loose crankshaft will give thuo
or a slap, and will cause the gears
to rattle at times. 1t is caused oy
worn or burned bearings or END play
in the shaft. A very heavy KNOCK
comes from the fywheel being loose,
which sound is produced regularly.
A loose piston in the cylinder and
loose valve rod often produce SIM
liar sound, being short slap or
knock. When coming from the pls-
a
the bore of the cylinder. When from
the valves it is caused by excessive
space between valve stem and push
rod, worn valve or rod guides, valve
seat out of true or bent or sticking
valve stem. Valve rod rollers or
poor cams also may cause KNOCK
2. Leaking sparkplugs will cause
motor to miss on heavy pulling or
high speed, and yet will not AFFECT
it in light pulling or slow speed
Cracked or porous condition of the
porcelain in the plug, or leakage
around the porcelain causes the trou-
Bile, allowing the high-tension cur
rent to ground without crossing the
spark gap.
g. Do not run a car on dead bat
terry. Although the generator is
usually protected with a fuse, which
can be removed when the battery is
not in use. to prevent excessive in
ternal current from damaging the
field and armature windingS. 1t is
wiser to play safe in attending to
the battery at regular intervals,
keeping it always in condition for
use.
4. The total number of motor
vehicles produced in the United
States during 1919 is 1,974.016, in
Guiding trucks.
s. Driving chains used on motor
cars are usually in three forms. the
Gil ri hQ q
block chain. The silent chain is COM
monty used to drive camshafts,
motors, generators and water pumps.
Roller chains are made to drive the
rear wheels on both automobiles and
trucks of some makes. and in some
cases drive the camshaft and trans
nit the crankirg power from the
starter to the motor. The block
chain is rarely used for driving pur-
poses on the machine at present.
6. There is a form of insurance
which applies to a car owner or an
damage in a collision. If an owner
whose car smashes up another per-
sons car has such insurance on the
car. this insurance will cover the cost
of the second as well as the first car.
If only one car is damaged in a col
lision. no matter which car it is, the
insurance covers the expense in
Cured.
Z. 1t is possible for a motor to
have too high compression. resulting
in knocking and pre-ignition. The
design of motor may cause this. or
in a case of the cylinder block being
lowered to obtain a tighter, fit be-
tween cylinders and crankcase or a
faulty gasket being used the knock
ing will result. The only remedy
is to elevate the cylinders slightly
by placing heavier gasket beneath
<hem.
s. The throttle does not wholly
control engine speed. The engine
load, which increases when additional
weight is placed in the car or when
She car leaves a level road to climb
a hill, is also factor. Thus when
car is loaded or going up
grade, it will not attain the speed
with wide open throttle that it will
attain when empty or on perfectly
level roads,.
9. A cause of smoking when the car
is driven at low speed is that On low
throttle opening, used frequently in
a city, the mixture drawn into the