The Washington herald., 1921-03-13


<work that piston rings really have
90 perform these little parts loom
up asrs big factor In efficient engine
-operation- The piston rings are
,nprtpgy rings OF iron which pack
xhe piston. and are supposed to
make . joint between piston and
cyiinder which will be 30 tight that
gas cannot pass, and. ct the same
'fime. ~ 80 free that undue friction
Etll bot BE- produced On the face
Of u. these seem like opposed qualf-
ties, In . sense they are. because
n the frtnEs were 20 tight a. to
preyent the smallest amount Of gas
or mixture from leaking past they
Nould at the same time cause too
muchvfriction against the cylinder
WAN. Upon the goodness with which
rings. ~ the piston and cylinder de-
Dendsothe retention of compression.
the completeness with which the
cylinder Is filled with gas. the power
produced by the engine, the extent
of carbonization due to burning oil.
and also. to large extent. the econ
emy OF operation of the engine. It
b vitality important to the car
owner, therefore, to know some-
thing about piston rings and how
they are fitted, for the At of the
ring In the piston and cylinder is
fhe-elus to . great many Ills.
There are hundreds of types of
pistor ffngss but In general use to-
DAT Mere are. perhaps. only a dozen.
OF fthH number two are in ordinary
usk& = These are called respectively
th< mter or diagonally split and the
sfepJHnt. These refer to the meth
Cd of futting the ring ends. because
much kof the trouble from leakage
10 tperto space allowed for leakage
IT tfe>ends Of the ring.
Many Special Types.
fS addition to these two types OF
rin1Es here are any number of makes
of sbecial rings which are designed
TO bsercome the major deficiency of
th4 NO named. that Is, leakage. at
tho adds. In every case some pat
ented means Is used for doing away
wikhS , space of any kind so that
the ring as 1t fits in its groove COM
pl<tely seals the cylinder. What [
wfoh 30 impress upon the reader Is
thtttthe piston ring itself must be
aceuretely fitted to the piston and In
the Scyiinder in order that a gas
ti4ht doint be had. II this is not
doeA regardless of the type of ring
thers SIS bound to be trouble from
eli o. gas leakage.
mrhtting piston rings allow. as
prtWsusly mentioned. the mixture
to- leak down into the crank case.
At the same time this mixture car
rfes with IL a certain amount of
w4ters which contaminates the oil.
AItos The lubficating oil working up
paetSthe piston rings causes an ap-
precixble carbin deposit and mis-
nrinE due to shortening of the plugs
anf Kindred troubles.
Bfpre new piston rings are fitted
the 1engine Interior should be thor
ouehly cleaned of carbon, because
carpon Is an abrasive and has a
cutting action on the bearings, cy-
liudsT walls and pistons-
First Measure Cylinders.
Befpre heeting new rings the
cylinders should be examined and
mezsured- II found out of round.
werped or scored. they should be
refrcnnd and overdiameter pistons
and PISTON rings installed. Piston
riqzg Smust have uniform wall pres
sufA o. sufficient strength to main
tain . bearing against the cylinder
wSllssduring every operation Of the
pfston. Rings that will assume the
shepe Of the worn or warped cylin-
der 90 not have the necessary wall
pressure and may collapse under the
foroe Of the explosion.
After cleaning the ring grooves
ofacatbon 1t Is Of the greatest i'm
pofR1ce to make certain that the
si4es of the grooves are true. Grooves
thetare V-shaped. staggered or have
round corners should be turned to
permit using the next width ring,
which may be had from any dealer.
De not expand the ring over the
pistcu until trying it in the groove
to- Which IL Is to be applied. Roll
the rfng all the way around the ring
groove and see that it enters the
groovs freely but not too loosely
and deep enough so that it extends
beIowths piston face at every point
II fhs ring grooves are too shallow