Pontiac tempest 1968 Service Manual page 282

V-8 E N G I N E 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 P I S T O N -
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 F i g .
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 P I S T O N -
C L E A N AND INSPECT
1. Clean carbon, varnish, and gum from piston
surfaces, including underside of piston head. Clean
P I S T O N
B A S E
S U P P O R T
T O START
REMOVAL
350
C U . I N .
; J6901-11
4 0 0
C U . I N .
! J6901-1
J 6 9 0 i 1
4 2 8
C U . I N .
, 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 B O R E S - I N S P E C T
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 F i g . 6-116 Normal Cylinder Wear Pattern