Tulsa daily world. [volume] (Tulsa, Indian Territory [Okla.]) 1905-1919, 1916-09-24

not in neutral Probably ninety per
cent OF these accidents have hap
pened after the driver stalled his
car. say to you, therefore, when
you stall your car forget the traffic.
forget your embarrassment, and
think to have gears In neutral and
your spark retarded. when you
stall, think of this paragraph.
When cranking, try to get into the
habit OF not putting the thumb
around the crank handle. keeping It
alongside OF the forcfinger, much as
you do when swimming. Should
you get kick back" when so hold
ing the crank handle. 1t will prob
ably pull ont OF your hand without
hurting you. The safest way to
crank is to pull up with the left
hand.
Where car is equipped with an
electric starting, or as II would be
better termed, an electric cranking
motor, the spark should be retarded
when starting. just as ii is when tho
cranking Is done by hand. AS Il
rule, the electric motor is strong
enough TO resist the bank kick and
even carry the piston past the dead
center. but the writer has seen many
starting motors torn to pieces and
retard the spark when starting.
So much FOR the point where the
spark must come when starting.
Where must II come when running?
Again the great speed Of the en-
CINE comes into account. We saw
from previous lesson (on the valve
tlming) that stroke of the engine
often takes place in 1-40 of sec
ond Now 1t takes n little time for
III ~ A.
can readily see that at the above
great speed. II the spark comes late,
all Of the power will not bc gotten
out OF the explosion. the piston sort
OF running away from the Easses
For this reason when the engine is
running the spark is made to come
before the piston has reached top
center as shown in Figure ., or. in
other words, the spark is advanced.
Thus when the piston has reached
top center all of the gases will have
had time to ignite and we get the
fun force of the explosion.
From the above we see that the
faster the engine rcvolvcs. the M re
the spark must be advanced, while
as the engine slows down, the spark
must be retarded.
Spark Knock.
Many drivers fail to pay any at
tention to their spark control levers,
and then wonder why there is n bad
knocking in the engine when the car
slows down on a hill This knocking
is what is known as a spark knock.
When on a hill. driver wishing to
get all the power out of his engine
possible, opens his throttle wide,
with the result that the explosion is
very powerful one. The engine.
l.
ably and If the spark lever is ad-
vanced IT is probable that the spark
will have come in the cylinders and
the gases have been fully gnted be-
fore the now slowly moving piston
has reached top center, or when II
Is in the position shown in Figure 2.
The force of the explosion will,
therefore. try to make the piston go
backward, or. i'm other words re-
verse the direction of revolution of
the engine. The forward movement
of the car and of the flywhcel, how
ever. will not permit this. Thus,
there is sort of struggle taking
place between the two forces. and if
there be any looseness in the engine,
there will be violent knocking.
From this we see that when climb
ing a hill, as the car slows down. the
spark should be slowly retarded. hut
should YOU shift to second. the
spark should Immediately be ad-
vanced again.
Refer for moment to Figure T.
Let us imagine that every time the
arm (A) which revolves the dircc-
tion of the arrow hits the point B,
that We would get a spark in the
cylinder of the engine. If now the
point B be moved a little in the di-
rcction opposite to that indicated by
the arrow, the arm A will hit it