Connecting Rod And Piston Assembly - Pontiac Grand Prix Service Manual

V-8
ENGINE 6-65
6. Push piston and rod assembly up far enough to
allow removal of bearing shell. Remove bearing shells
from rod and cap.
7. Inspect crank pin for damage, out-of-round, and
taper.
8.
Reassemble cap and rod with new bearing shells and
check fit, using Plastigage, or equivalent, as outlined below.
CAUTION: Under no circumstances should a bearing
cap be filed or shimmed in an effort to affect a fit.
NOTE: In 1969, a number of 2 bbl. equipped V-8's will
have .OliY' undersize crankpins. These crankshaps may
be identifed by a
.OliY'
U.S. stamp on the front of the
No. I counterweight and the rear of No. 8 counterweight.
A check should be made for this undersize crankshap
before replacing rod bearings.
PLASTIGAGE, OR EQUIVALENT, METHOD
FOR DETERMINING CONNECTING ROD
BEARING CLEARANCE
1. Remove the cap of the bearing to be checked. Wipe
the bearing and the crank pin free of oil.
2.
Place a piece of type PG-1 Plastigage, or equivalent, the
length of the bearing (parallel to the crankshaft) on the
crankpin or bearing surface. Install the cap and tighten
cap bolts to 43 Ib. ft.
NOTE:
Do not turn crankshaft with Plastigage, or
equivalent, in place.
3.
Remove bearing cap and using Plastigage scale, or
equivalent, on envelope (Fig. 6-111). measure width of
compressed Plastigage, or equivalent, before removing it
from the crank pin or bearing. If the bearing clearance is
between .0005" and ,0025". the clearance is satisfactory.
If clearance is more than
.0025",
replace bearing with the
next size undersize bearing and recheck clearance. Bearings
are available in
.001"
and
.002"
undersize.
4. Rotate the crankshaft after bearing adjustment to be
sure bearings are not tight.
CONNECTING ROD AND PISTON ASSEMBLY
REMOVE
1. Remove oil pan, oil baffle and oil pump (see OIL
PAN
-
REMOVE AND REPLACE).
2. Remove intake manifold and cylinder head on bank
from which piston is to be removed.
3. Rotate crankshaft so crank pin carrying assembly to
be replaced projects straight downward (Fig. 6-1 12).
4. Remove ring ridge (Fig. 6-1 13) using suitable ring
ridge remover.
5. Remove bearing cap and install connecting rod bolt
guide set J 5239.
6. Carefully remove connecting rod and piston assem-
bly by pushing out with knurled handle of long guide
(Fig. 6- 1 14).
REPLACE
1. Install connecting rod bolt guide set on connecting
rod bolts with long handle guide on same side as oil
groove in rod.
2. Using J 8037 (Fig. 6- 1 15) ring compressor, insert
piston connecting rod assembly into cylinder so that
notch in top of piston is toward front of engine. Be
certain oil spurt hole (Fig. 6-122) in connecting rod is
toward camshaft.
3. From beneath engine, pull connecting rod, with
bearing shell in place, into position against crank pin.
4. Remove guide set J 5239. Install bearing cap and
cap nuts and tighten to 43 Ib. ft. torque.
5. Replace oil pump and oil baffle, if they were
removed.
6. Install cylinder head and intake manifold.
CONNECTING ROD AND PISTON ASSEMBLY
-
RECONDITION
NOTE: Use care at all times when handling and
servicing connecting rods and pistons. To prevent
possible damage to these units, do not clamp rod or
piston in vise since they may become distorted. Do not
allow pistons to strike against one another, against hard
objects, or bench surfaces, since distortion of piston
contour or nicks in sop aluminum material may result.
DISASSEMBLE
1.
Remove piston rings, using J 802 1 or J 7 1 17 piston
ring remover.
NOTE: It is important that rings be removed carefully
to prevent scratching or burrrng 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 insert in Fig. 6-116 for
correct base support and pilot plunger for the type
pistons being serviced.
3. Using the pilot plunger (or plate) indicated in Fig.
6-1 16, the piq may be pressed out far enough to index
with the bore in the base.
4. Remove pilot plunger and spring from base.