The Washington herald., 1917-09-16

Carbon deposits in the internal COM
bustion engine are like measles In
children = inevitable. They particu-
larly afflict the cylinders, the piston
heads, the valves and valve seats.
The substance is the residuum left
from the burning of gasoline and oil.
In the beginning the carbon deposits
are simply in the form of dust, ou,
gradually as oil comes into contact
with the carbon and enters the mass,
it becomes a cake, which is hard
enough to Require a chisel or similar
tool for removal.
The presence of carbon interferes
with the operation of the engine. Tc
begin with, the motor loses its ac-
customed pep" and a proportion Of
its power; overheating may result
and misfiring and backfiring are
pretty certain to set In sooner OF
later; the engine cannot be throttled
down satisfactorily and frequently
firing continues after ignition has
been shut of; a knocking may de.
velop and the engine may not respond
readily to the spark advance. All
in all the power plant will become
sluggish in action. as IL 1t were suf.
fering from senile decay.
So much for the effect of carbon
Oh the body of the engine, but II
exercises just as baleful an influence
on the action of the valve system
Here the carbon is deposited on botr
the valve faces and the seats. Tiny
particles of this hard substance are
gradually ground into. the metal, un.
I'll they prevent the valves from seat.
ing properly. The result is that the
fuel escapes from the combustion
chamber, compression is seriously
lessened and eventually misfring will
result.
carbon also is deposited on the sparL,
plug ends in such a way as to cause
short circuit.
Probably the commonest carbon
trouble is from deposits in the cylin-
der- These deposits consist OF small
Particles protruding into the combus-
ton chamber. They become incandes-
cent with the heat of the explosion
and retain their white heat long
enough to fire the next incoming g
charge. This results In Just the same
metallic knock that comes from ad-
vancing the spark lever too far.
When the combination of lack OF
power, overheating and knocking oc-
ours, the car owner may be certain
tnat he has a case of carbonization
on his hands. In a new car these
symptoms sometimes occur after 300
miles Of running, but generally 5OC
miles is the beginning of this trou-
bic. The new car requires an excess
OF oil. and a rich mixture and burn
ing oil is the greatest source of car
bon deposits, hence the rapid forma-
tion during the early operation of the
vehicle. OF course gasoline also pro-
duces carbon II the mixture is too
rich, much of the gasoline vapor burns
instead of exploding and the result is
carbon. Obviously then, correct lubri-
cation, not an excess of oil and a
properly proportioned fuel mixture
will do much to prevent carbon de-
posits, very much more desirabl
solution of the problem than remov-
ing them afterward.
Within recent months there have
been placed upon the market a num-
ber of devices generally called steam
injectors. which introduce live steam
from the cooling system into the fuel
vapor. These are claimed to remove
carbon from the cylinders and prevent
its ever forming again. We doubt the
ability to remove carbon already form
ed. but the introduction of the steam
into the combustion chamber does
cause any carbon formed to enter
into a chemical combination with the
gases of the explosion and leave moth
ing in the chamber. AS a preventa-
tive, then, these devices have merit
and any reader interested may obtain
list of concerns manufacturing them.
Now as to the removal of carbon de-
posits already formed. There are a
number of methods of doing this
work; there is the time-honored trick
Of introducing kerosene into the CYL
inder in the hope that it will act as a
solvent OF the oil holding the carbon.