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28
Chapter I-General Engine Repair
Fig
.
45-Cylinder Ridge Removal
allowable p
ull,
check for a damaged
piston,
try a new
piston,
or hone
the
cylinder
bore
to
obtain the proper
fit.
If
the
scale
readin
g is
less
than
the
minimum
allow-
ab le
pull,
try
another piston.
If
none
can
be
fitted,
re-
bore
the
cylinder
to the next oversize piston.
NOTE
:
All
pistons
are
tir
e
same weight,
bo
th
sland·
ard and
oversize;
th
ere/ore
pisl.on
s of variolJ,s sizes
can
be
interm,;xeci
without
upse/,l ing
en
gin
e
IJal·
ance. R
e bore only
th
e
cylinder
or
cylin fl
e
rs
which
require
it.
(4)
FITTING PISTON PINS.
The
piston
pin
should
have
0.0001-0.0003 inch clearance in both the
con necting
rod and
the piston.
If the piston pin
hole
must
be
reamed, use
an expan-
sion-type
piloted reamer. Place
~he
reamer
in a vise
and
revolve
the piston around
the
reamer.
Set
the
reamer
to
the size
of t
he
pin bore,
the
n
expa
nd
the
reamer slightly and
trial
ream
the pin
bore,
using
a
pilot
sleeve of
the
n
earest size
to maintain
al ignment
of the bores.
CAUTION:
Take
a
very
lig
hl
cuI.
Check
the reamed
hole
size,
using the piston pin for
the
piston
being reamed.
If the bore
is small, expand
the
reamer slightly
a
nd m
ake a
nother
tria
l
cut.
R epeat
the
procedure
until the proper fit is obtained.
(5) FITTING
PISTON RINGS.
Install
the
ring
in
the
cylinder
bore.
I
nvert the piston,
a
nd
use
the
top
Groove C/eoning Tool
T52L
-
6110-
AAO
Fig
. 46-
CJeaning
Ring
Grooves
6097
13
__ - -
Pis/on pull scale
Thickness scale
6215
Fig
.
47-Piston Fit Check-Typical
to
push
the
ring
about
ha
lfway
down
the bore to
square
the
ring.
M
easure
the ring
gap
with
a feeler
gauge.
B
e
sure
to identify the rings with the piston
and
bore
in whic
h
they are to
be
u
sed.
Check
the ring to groove side
clearance
with
the
rin
g
installed
on
t
he proper
piston
(fig.
48
).
Whe never
piston rings
are
installed in
a
used
cylin-
der,
the
ugl
aze "
on
the bore
should
be
removed to aid
in
ring
seating.
c. Conn ecting R ods.
(1) CLEANING
AND
I
NSPECTION. Clean all
parts
and passages in
solven
t.
N ever
use
a caustic cleaning
solution.
R
emove the bearing
inserts
(identify
the
m
Fig. 48-Ring Clearance Check
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