Evening star., 1921-01-30
Answer. to Last Questions.

AnS"eFS TO LASGSW eek0 questions.
1. The enginST transmission and
clutch assemblaT in the Same case
form the unit power plant commonly
used in modern cars. 1t is used to
great extent because the depreciation
is lessened and efficiency Is increased
by this method of assembling, due to
the fact that all members Of the unit
are held Mn perfect alignment during
the entire life of the car. Strains or
stresses will not throw them out of
line under any driving conditions.
q. Overheating Is q common cause
Of g knock which increases as the
car is driven and Is due to faulty
lubricating or cooling and carbon de-
a car which increases knocking as the
car goes uphill has either an accumu-
lation Of carbon or the sparkling is
too far advanced-possibly both.
3. II the spark plugs are dry but
sooty the fabrication Of the engine
is correct. but the carburetor mixture
is too rich. If the plug is oily it in
dicates too much oil being drawn
into the combustion chamber past pis-
ton rings. If the plug is both sooty
too much gas and oil being consumed.
4. Sudden misf1ring in the engine,
especially when it has been firing reg
ularly, is usually caused by fouled
spark plug or disconnected wire lead
ing to the plug. The first thing to do
is to ascertain II the missing occurs
regularly and in certain cylinders. or
if all cylinders miss fire irregularly.
The former is caused by the above
mentioned trouble the latter by
fouled plugs or dirty timer or distributor
contacts.
5. The carburetor float is necessary
to prevent gasoline from oyerfowlng
the carburetor when the engine is
idle. Connected to the float is a gaso-
the float rises with the gasoline ad-
mitted to the float. chamber of the
carburetor the needle valve slowly
shuts off the fiowef gasoline. until
certain height is reached, when the
flow to the carburetor is cut off en-
ber is reached by incoming gasoline
before each charge Of fuel is drawn
into a cylinder. Thus the float rises
and falls once for each explosion in
the engine.
6. If the exhaust system emits an
unusual noise when the cutout is
closed it indicates q leaking or dis
connected joint somewhere in the ex-
haust pipe or muffler or at the point
where the exhaust manifold connects
to the engine.
Z. A cause Of a beam of light from an
the side of the road. in the air or on
the ground near the car is due to the
electric buTb itself in the headlight.
The bulb may not be centered in the
lamp reflector, pointing down, up or
to the side, or the, filament within the
bulb may not be in the center. so that
the light will be thrown incorrectly.
If the light and bulb are set correctly,
examine the lamp bracket or support.
It may be sprung out, Of true:
8. Clutch leather which is worn or
exceedingly dry, or in a case of
clutch which revolves in oil, a lack of
oil or the wrong, grade of oil. will
cause sudden grabbing-of the clutch,
causing a car to jump forward sud-
denly when it is first started.
9. Babbit. white brass or bronze or
other soft metals are usually used for
connecting rod bearings. because if
undue friction or heat were produced
at the bearings, as in the case of not
enough lubricating oil, these bearings
would wear or melt, without injuring
the crank shaft. a hard-metal bear
ing would tend to score or wear the
shaft, in which case the bearing sur
face also will be ruined. Soft-metal
bearings are more easily fitted to the
connecting rod and their adjustment
is more simple.
battery is very seldom met with in
the modern car. Generators in
variably are equipped with some sort
Of cutout or circuit breaker which
disconnects the supply of current to
the battery when a certain high
speed is attained by theacar.
This Weeks Questions.
l.. Is there any, harm done in
using the engine as~ a brake on down
grade when the foot brakes would
become hot if used continually?
2. Why should good grade of
spark plugs always be used in the
engine? IL
8. When the speed Of a car slack
ems and the car finally stops. but the en-
CINE continues to run, where should