The Palatka news and advertiser., 1915-07-16

| What is the reason for heating the
mixture before it goes to the cylinders
| for combustion?
The only reason that we preheat fuel
| is to thoroughly vaporize it. In other
words, for given volume and given
| mixture Il great amount Of heat units
will be contained in the cooler charge
provided that both are completely va
| porized. The reason for this Is that
| the heat expands the charge, thereby
permitting smaller number of units
| of discharge to be contained in CIV
en- volume. The fact that some OF the
| heat units which would ordinarily be
| lost are returned to actual use by pre-
! heating the charge is factor in the
situation and does reduce the differ
ence between the two conditions. but it
is doubtful If as many heat units would
| be given up in tins manner as would
| be lost by having Il preheated charge.
| The practical side of the question. how
ever is one which must he looked upon.
With the gasoline that we are now get
ting ii is necessary To use heated air
if the best results are to be attained;
otherwise the fuel will not be vaporiz-
ed. especially during cold weather.
How many teeth are needed for two
to one and two and half to one ratio?
The gears should be such that there
are twice as many teeth on the large
gear as there are on the small gear,
in order to get TWO to one ratio. For
a two and One-half to one there should
be two and one-half times as many
teeth on the large gear as there are on
the small one The ratio may be OBJ
tanned with an infinite number of COM
binations. The size of the gearcase
will determine the size of the gears.
and then the shape and distance be-
tween teeth must be found to get the
number of teeth needed.
Is there any possible way in which
can install a pressure feed oiling sys-
tenn on my car? It has splash system
at present.
1t might be possible to install this
pressure feed, but it would not be ad-
visable. In the first place, a great
amount of special engineering work
would be required and many new
parts, such as a hollow crankshaft
and the pump itself. This would en-
tail a great outlay of money which
would not be justifiable, because, aft
er the system had been worked out
and installed ON the motor, the under.
taking would in every sense of the
word, be an experiment. ANY trou.
bles you may have been having with
your oiling are probably not due to the
original design, but to some local de-
feet which has come up and which can
probably be readily cured in a much
more simple way than by altering the
entire system.
Should the clutch be thrown out on
rough roads?
The clutch should be thrown out
and the brake applied slightly when
deep ruts are encountered, and many
drivers make riding easier by period
ically throwing the clutch on rough
roads. If the motor will pull slowly
there is no reason, however, for throw
ing out the clutch.
What valve timing should one use on
a two cylinder opposed motor with
bore of four and a quarter and stroke
of four and half?
Since the valve timing which will
give ideal results for any given motor
g.,
largely upon such details as manifold
design, the only thing which can be
done is to give an approximate timing,
from which you can vary in one direc.
ton or the other until you attain the
best results. If the cams are already
made and in the motor you can only
place them so that the valve openings
will correspond with those given and
allow the closing to take care of itself.
A fairly average timing which should
give good results is as follows: Intake
valve opens ten degrees after upper
dead center and closes thirty-ive de.
grees past lower dead center. Exhaust
valve opens forty degrees before lower
center and closes five degrees past up.
per center.
Does il harm a high tension magnetic
that is, where a car is run by one
alone-to shut off the spark going down
hill and brake with your gears? Is this
the best thing to do on a steep hilI2
And could this harm the cylinders?
1t does not harm high tension mag
neto to do this, as no mechanical strain
is put upon 1t. and naturally it does
not generate current when switched
off. The practice of using the motor
as brake will not harm the cylinders,
but it is said to put considerable wear
on the gears. due to the reversed ac-
tion of the reduction-that is, If the car
should be geared four to one when the
motor is acting as brake the reduc-
ton acts In an opposite direction and
becomes one to four.
How can | stop rattling of scissors
type shock absorbers without tighten
ing up the bolts until the car rides
hard7