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6A3-20
1977 PONTIAC SERVICE MANUAL
Fig. 6A3-42 Correctly Fitted New Piston
Fig. 6A3-43 Correctly Fitted Used Piston
ASSEMBLY A N D INSTALLATION OF
PISTON A N D CONNECTING ROD
ASSEMBLIES
Connecting rods may be sprung out of alignment in
shipping or handling. Always check a new rod before
installing piston and pin.
Check bend and twist on an accurate rod aligning fixture
using Guide Pin J 6047-20 in place of wrist pin. Press V-block
firmly and evenly against guide pin to prevent cocking pin
in eye of rod which may be up to .00125" tight on pin.
1. To assemble piston and pin to connecting rod, use
piston pin remover and installer J 24086.
2. If the piston and rod assembly is to be installed in the
left bank, the assembly must be made as shown in Figs
6A3-44.
3. If the piston and rod assembly is to be installed in the
right bank, the assembly must be made as shown in Figs
6A3-45.
4. Lubricate piston pin to avoid damage when pressing
into connecting rod.
LEF
1
NO. 1-3.5
BOSS ON ROD TOWARD
L
Fig. 6A3-44 Left Bank Piston and Rod Assembly
TOWARD FRONT
OF ENGINE
OF ENGINE
Fig. 6A3-45 Right Bank Piston and Rod Assembly
5. Install piston pin on installer and pilot spring and pilot
in support. See Fig. 6A3-46.
6. Install piston and rod on support, indexing pilot
through piston and rod.
7. Place support on press, start pin into position and
press on installer until pin pilot bottoms.
8. Remove piston and rod assembly from press. Rotate
piston on pin to be sure pin was not damaged during the
pressing operaton.
9. Install piston rings as shown in Fig.s 6A3-47. Position
expander ends over piston pin. Install oil ring rail spacer, and
oil ring rails. Position gaps in rails so that when piston is
installed in its bore the gap will point toward the camshaft.
Install compression rings in upper two grooves.
a. Top compressing ring
-
When installed, the
manufacturer's
indentification mark
("0",
" D O T o r
"TOP") facing up.
b. Second compression ring
-
When installed, the
manufacturer's identification mark ("Ow, "DOTWor "TOP")
facing up.
c. Oil ring
-
Can be installed with either rail facing up.
Some engines have a 2 piece oil ring, which has only one rail.
The rail must be installed at the top of the oil ring groove.
d. Ring gaps
-
All three ring gaps must be 90" apart. See
Fig. 6A3-47.
10. Make sure cylinder bores, pistons, connecting rod
bearings and crankshaft journals are absolutely clean, then
coat all bearing surfaces with engine oil.
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