The sun., 1919-04-20
PISTON RINGS AND
HOW TOPIT THEM
Expert Tells Just How This
Important Operation
Should Be Done.

When one stops to think OF the work
chat piston rings really have to perform
these little parts loom up as big factor
IN efficient engine operation. The piston
rings are springy rings of iron which
pack the piston and are supposed to
make Joint between piston and cyln-
der which will be so tight that gas
cannot pase and at the same time be so
free that undue friction will not be
produced. On the face OF II these seem
tfke opposed qualities. In sense they
are. because II the rings were so tight
as TO prevent the smallest amount OF
gas or mixture from leaking past they
would at the same time cause too much
friction against the cylinder wall. Upon
The goodness with which rings At the
piston and cylinder depends the reten-
Zion OF compression, the completeness
with which the cylinder Is filled with
gas. the power produced by the engine,
the extent of carbonization due to burn
-, ing oil and also to large extent the
economy of operation OF the engine. II
Is vitality important to the car owner
therefore to know something about pis-
ton rings and how they are fitted. for
che fit OF tho ring In the piston and
cylinder Is the clue to great many lis.
There are hundreds OF types OF piston
rings, but in general use to-day there
Ore perhaps only dozen. OF this num-
Der two are in ordinary Use. These are
called respectively the inter or dlagon-
city split and the step Joint. These
refer to the method of cutting the ring
ends, because much OF the trouble from
leakage is due to space allowed for Leak
age al the ends OF the rins. u
In addition to these two types of rings
there are any number OF makes Of spc-
cial rings which are designed to over
come tie major deficiency OF the two
named. |. e., leakage at the ends. III
every case some patented means is used
for doing away with a space of any kind
90 that tho ring as Il fits in its groove
completely seals the cylinder. What
wish to impress upon the reader is that
The piston ring itself must be accurately
fitted to the piston and in the cylinder In
order that gas tight Joint he had. II
this is not done regardless OF the type
OF ring there Is bound to be trouble from
oil and gas leakage.
III fitting piston rings allow. as pre-
vlouely mentioned. the mixture to leak
down into the crank case. At the same
this mixture carries with II n certain
amount OF water, which contaminates the
oil. Also the lubricating oil working up
past the piston ring causes an appre-
ciable carbon deposit and mlsflrins due
60 shortening OF the plugs and kindred
troubles.
Before new piston rings are fitted the
engine interior should be thoroughly
cleaned OF carbon. because carbon Is an
! abrasive and has cutting action on the
bearings. cylinder walls and pistons.
= Before hitting new rings the cylinders
should be examined and measured. If
found out OF round, warped or scored.
. they should be reground and overdlam-
I eter pistons and piston rings installed.
Piston rings must have uniform wall
pressure OF sufficient strength to main
tain a bearing against the cylinder walls
during every operation of the piston.
Rings that will assume the shape of the
worn or warped cylinder do not have the
necessary wall pressure and may col
lapse under the force of the explosion.
! After cleaning the ring grooves OF
carbon 1t is Of the greatest Importance
to make certain that the sides Of tho
! grooves are true. Grooves that are W
3 shaped. staggered or have round corners
should be turned to permit using the
+ next width ring, which may be had from
any dealer.
i Do not expand the ring over the pts-
Z ton until trying II In the groove to
which IL Is to be applied. Roll the ring
all the way around the ring groove and
see that 1t enters the groove freely but
not too loosely and deep enough so that
ii extends below the piston face at every
point. II the ring grooves are too shall
low before deepening them see that the
corners are clean. II the ring binds on
the sides OF the groove look first for
carbon; II none, rub the ring evenly on
hne emery cloth on a smooth fiat sur
face until the desired Al Is attained
d. Each ring should be fitted to the groove
IN which Il Is to be placed. Expand the
ring to be used in the bottom groove
insert three one-half inch by six inch
sAids, cut from an old saw blade or any
other light, plianle metal. ono under
each end o. the ring and the third at the
back. Slide the rings down over the
Gai!ds. Install the bottom ring first. and
90 on from bottom to top until all are In
place. OIL we'll and rotate In the grooves
TO make sure that all dirt and foreign
matter Is removed
Bear In mind that a certain amount
OF clearance must be left at the ring
ends. and this clearance must be main
tained when the rings are In position
IN the cylinder. In checking this clear
ance in diagonally split ring compress
the ring as much as possible while II Is
in Its groove and measure the clearance
at the ends. This will vary with the
size OF the ring, but usually ii is 1-32
OF an inch. The game clearance should
be allowed In step joint ring. In spe-
c'al rings provision is made for this
clearance. Some owners in fitting rings
Imagine that II they are tight they will
at better II II easy to see that II the
ring is tight when the metal is cold It
VIII become considerably tighter when
II gets hot, and the result will be stuck
piston ring, which Is not an uncommon
cause OF loss OF compression and power.
In order to avoid this condition the ring
must be free In It's groove and yet no
UP and down play must exist