The news scimitar. (Memphis, Tenn.) 1907-1926, 1919-04-12
Carbon at Spark.

~
still another resting place that at
tracts carbon Is the end OF the spark
plug, and It Is not uncommon to find
short circuits resulting from this cause.
A bridge OF carbon offers little Iesis-
lance TO a current of electricity,
Carbon deposits In the combustion
chambers, II they were examined an
der the microscope, would be found to
embody also innumerAble tiny projec-
out which become i~ncandescent and
fire the incoming charge before the
piston has reached the top OF the CYL
lnder. The result is the downward
blow OF the exploded gas exerted on
the piston as II Is still rising, and a
knock is heard.
that every engine knock is from car
bon deposit, although that Is the oom-
monest cause. Too great an advance
OF the spark will cause knocking and
so will a dozen other things. But when
knocking begins and Is accompanied
by overheating and loss of power, the
bon deposits In the cylinders,
As with most things, prevention Is
better than cure, The car owner should
observe certain rules that will tend to
keep down the deposit of carbon In his
engine. II the car Is habitually driven
on too rich. a gasoline mixture, carbon
deposit will be rapid, as will be the
The reasons behind this are apparent
on a little thought. The gasoline mix
ture that Is too rich is slow burning:
instead Of exploding %snappily It burns
and much Of the contents Is never ex-
ploded, but burns incompletely, leaving
a lot Of carbon. When excessive oil Is
used the excess forces its way past
the piston rings and burns with the
gasoline, leaving a heavy soot deposit.
To this base comes dust drawn into
the engine with the air, which, burn
Ing, helps make the deposit almost
adamant In It's hardness,
The car owner, therefore, should be
very careful to give his engine the
proper gasoline mixture, and to see
that while enough oil is always pres
ent, there is never an excess, Follow
Ing these two rules will keep carbon
deposit at an inevitable minimum.
Some Cures.
There have recently been introduced
to the motoring public q number of de-
vices intended to help In solving this
carbon problem. These are y~arlously
known as water and steam injectors,
vaporiEers, etc. Tn operation they take
q certain amount of water or steam
from the cooling system and inject IL
into the combustion, and It is frequently
claimed cleans out carbon deposits al
ready formed. II Is doubtful II a va
porizer can dissipate carbon deposits
that have already formed. but II one OF
these VaporiEers Is placed In operation
In an engine that has been thoroughly
cleaned of carbon 1t tends to reduce
or eliminate future deposits. On that
score alone the vaporlzer has justified
Its existence,
The removal OF carbon deposits al
ready formed may be accomplished in
several ways, The time-honored meth
Cd of scraping the carbon out with
tools specially devised for the pro.
a detachable cylinder head. In this
way the operator can be sure that ey.
cry bit OF the carbon has been re-
moved. Barring scraping, the oxyger
method OF removal is satisfactory, In
this method the oxygen Is led into the
CYLINDER through a spark, plug open
Ing, and a lighted match cause the
carbon TO burn to carbon dioxlde, {
gas, In cases where time Is brief
this oxygen method will be found ex.
tremely useful, In addition TO thes,
methods, there are various ways Of us
Ing kerosene, denatured alcohol, etc.
to loosen the carbon, and there arr
various proprietary compounds for tn,
same purpose,
Any engine that has had Its carbon
removed certainly needs to have IA
valve system cleaned up. The valve,
must be ground, There is no need /,
so into the methods here OF removlni
tho valves from the engine, but let /
be said that 1t Is wise to mark eacl
OF the valves 30 that they may be re.
turned to the proper cylinders after OPP
erations are over.
Before beginning to grind the valve,
the opening into the cylinder Shout,
be stuffed with cloth to prevent In
grinding compound getting into In,
cylinders, Next cover tho face Of thi
lightly with grinding compound.
coarse grade Of this latter II the valy
Is badly pitted Now slip tho vniy
into its seat and then osotllate II wifi
one Of the valve grinding tools ina
are available or with a screwdrlveI
After about 4 minute of this treatmen
the valve should be taken out an,
dipped In gasoline, and the seat ais
cleaned with the Same. liauid. II IN
grinding Is complete, the face Of Ia
valve and the seat will show an eve
gray color, n the pittinE has bee
too deep the grinding must be con
tinued until the smooth ~grayness ha
been secured,