Evening star., 1921-02-06
QUESTIONS AND ANSWERS
FOR THE AUTOlNOBLLLS7,S
Answers to Last Weeks Questions.

Answers to Last Weeks Questions.
l. No harm will be done the engine
If 1t is used as a brake. as on hills,
providing that this is done at the be-
ginning of the hill or. if not used at
the beginning. it is first speeded up
equivalent to car speed before clutch
is engaged. II the car Is allowed to
go down a mill Independent: of the
engine, as in coasting, an:. when the
bottom is reached If gears were en-
gagged and clutch let In without first
speeding up the engine. the result
would be verX sudden Slackening of
car speed and the strain in breaking
this speed would all be taken by the
driving system. This has been the
result Of wrenching the clutch. uni
versal, transmission or differential
out Of alignment or the breaking Of
some member of the drive system.
When you have reached the bottom Of
the hill before letting in the clutch
start your engine and speed it up to
car speed.
2. A good grade of spark plug
should always be used in the auto
mobile engine to insure against leak
of compression or current. as fire.
quently happens in poor plug. Aft
er a period of use a cheap spark
plug insulation becomes porous. caus-
ing a weak spark, and will leak COM
preston at the points where 1T is
put together. The result is poor ac-
celeration. and missing on high speed
in heavy pulling.
3. If your car stops on the road
unintentionally on the drivers part
but the engine continues running, first
look beneath your front floor board
at the clutch or tranmission. as 1t is
probable that the clutch has in some
or the gears have been disengaged,
or the gears have been disengaged
cutting off power to the rear wheel.
1t could be possible that the drive
shaft or one of the universals has
been broken or that gears Of the
transmission or differehtial are strip
ped. This, however. would not hap
pen without more or less noise result
ing. which would, of course, be notice.
able.
4. 1t is necessary for an exhaust
valve to open early, or before the
piston reaches end of power stroke, to
insure the complete passing out Of
burned gases. as the gases exert
considerable pressure and require
more time to insure their complete
expulsion from the cylinder than
would be given If the valve opened at
the end of or after power stroke.
5. Animal oils or greases or those
of a vegetable source should not be
used in the automobile. because they
contain acid which eats into the sur
face of the bearings or any friction
surface in the car. roughing 1t. leav-
ing rust deposit and increasing fric-
tion and wear. Also this kind of oil
or grease becomes rancid and oxi-
dies and gums the bearings.
6. The real cause of sand blister
in a tire casing is a cut which goes
through the tread rubber of the tire,
but only as far as the fabric or cord
underneath the tread. If the cut is
neglected and left open. sand. gravel
and water will work into it and will
gradually spread between fabric and
tread, forming in lump.
Z. Frequent burning out of fuses
in the electric system is caused by
short circuit somehere in the wiring.
1t may be in the lamp socket and
the lamp itself or loose wires leading
to the socket which are in contact
with some metal part Of the car.
s. The clutch of the dry cone type
will slip even If the friction surfaces
are not oily If the leather facing of
the cone is worn, glazed or burned.
Slipping is the result of smooth
hard surface of this leather. which
should be renewed.
9. Noise in the rear axle may be
caused by several different things.