Connecting Rod To Piston - Assemble; Piston Pin Replacement; Piston And Rod Assembly - Pontiac Grand Prix Service Manual

6-30
1969
PONTUC SERVICE MANUAL
As pistons w e a s u r e d they should be marked for
sue identification and measurements recorded.
If there is excessive clearance between a cylinder bore
and piston which was installed in that bore, a new
piston should be used.
New pistons are serviced in standard sue and .001",
.002", .005", .0 lo", .02OU and .030" oversize.
NOTE:
Since these are nominal or basic sizes, it is
important that new pistons be measured to ensure proper
fit. All new pistons are serviced with selectively fitted
piston pins.
After all measurements have been made, match new
pistons with cylinders where they will fit with proper
clearance. Honing cylinder bore may be necessary to
effect a proper fit. When properly mated, mark pistons
with cylinder numbers they fit so they will not become
mixed.
CONNECTING ROD TO PISTON - ASSEMBLE
There is a notch cast in top of all piston heads to
facilitate proper installation. The piston assemblies
should always be installed with notch toward front of
engine.
1. Lubricate piston pin holes in piston and connecting
rod lightly with graphite lubricant.
Fig. 6-61 Piston Pin Replacement
2. Position connecting rod in its respective piston so
that oil squirt hole faces toward distributor side of
engine. Fig. 6-60.
3. Install piston pin on installer and pilot spring and
pilot (J 9510-4) in support (Fig. 6-61). Use piston pin
removing and installing tool J 95 10.
4. Install piston and rod on support, indexing pilot
through piston and rod.
5. Place support on arbor press, start pin into position
and press on installer until pin pilot bottoms.
6. Remove installer and support assembly from piston
and connecting rod assembly.
7. Check piston pin for freedom of movement in piston
bore.
PISTON RINGS
-
REPLACE
1. Remove connecting rod and piston assembly
(see
CONNECTING ROD AND PISTON ASSEMBLY
-
REMOVE AND REPLACE in this section).
2. Remove piston rings using J 8021.
3. Clean carbon, varnish, and gum from piston
surfaces, including underside of piston head. Clean
ring grooves, and oil holes in oil ring groove, using
suitable cleaning tools and solvent.
4. 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.
Fig. 6-60 Piston and Rod Assembly
5. Inspect bearing shells to see that they are service-