V-8
ENGINE
6-85
Do
not allow pistons to
strike
against one another,
against
hard
objects,
or bench
surfaces,
since
dis-
tortion
of piston contour or
nicks
in soft aluminum
material
may result.
CONNECTING
ROD
AND
PISTON-
DISASSEMBLE
1. Remove piston rings, using J 8021 or J 7117
piston
ring
remover.
NOTE:
It is important that
rings
be removed
carefully
to prevent
scratching
or
burring
of
ring
grooves
and lands.
2.
Using a suitable arbor press place the spring
and
plunger into the bore of the base support and
position on an arbor press with the pilot plunger
indexed in the bottom of piston pin bore. See Fig.
6-115 insert for correct base support and pilot
plunger for the type pistons being serviced.
3.
Using the pilot plunger (or plate) indicated in
Fig.
6-115, the pin may be pressed out far enough
to index with the bore in the base.
4. Remove pilot plunger and spring from base.
5. Complete removal of pin using pin
driver
J
6901-3
and base alone.
6. Remove bearing cap and bearings.
CONNECTING
ROD
AND
PISTON-
CLEAN
AND
INSPECT
1.
Clean
carbon,
varnish,
and gum from piston
surfaces,
including underside of piston head.
Clean
PISTON
BASE
SUPPORT
TO
START
REMOVAL
350
CU.
IN.
;
J6901-11
400
CU.
IN.
!
J6901-1
J690i
1
428
CU.
IN.
,
J6901-11
1
J
6901-5
—J
6901
ring
grooves, and oil
slots
in oil
ring
groove, using
suitable cleaning
tools
and solvent.
2.
Clean
piston pin, rod, cap, bolts and nuts in
suitable solvent. Reinstall cap on connecting rod to
assure
against subsequent mixing of caps and con-
necting rods.
3.
Carefully
examine piston for rough or scored
bearing
surfaces;
cracks
in
skirt
or head; cracked,
broken,
or worn
ring
lands; scored, galled, or worn
piston
bosses.
Damaged or faulty pistons should be
replaced.
NO
TE: If piston pin bosses are rough or worn
out-of-round
and the piston is otherwise
service-
able,
the pin bosses may be honed for oversize
pins.
Before
fitting oversize
pins,
however, it is
advisable
to check fit of piston in
bore.
4. Inspect piston pin for scoring, roughness, or
uneven wear.
5. Inspect bearing shells to see that they are
serviceable.
Fit of bearings should be checked when
engine is being assembled.
CYLINDER
BORES-INSPECT
Inspect
cylinder bores for out-of-round or exces-
sive taper with an accurate cylinder
gauge
J 8087 or
comparable,
at top, middle and bottom of bore.
Measure
cylinder bore
parallel
and at right angles
to the center line of engine to determine
out-of-
round.
Variation
in measure from top to bottom of
cylinder
indicates taper in cylinder.
Fig.
6-116 illustrates
area
in cylinder where nor-
mal
wear occurs.
Cylinder
bore can be measured
by setting cylinder
gauge'
dial
at zero in cylinder at
the point of desired measurement.
Lock
dial
indica-
tor at zero before removing from cylinder, and
measure across the
gauge
contact points with outside
micrometer
with
gauge
at the same zero setting
when removed from cylinder
(Figs.
6-117 and 6-118).
Fig.
6-115
Removing
Piston
Pin
Fig.
6-116
Normal
Cylinder
Wear
Pattern
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