GMC C Series 1993, Repair Manual

Page: 189 / 264

V8 ENGINES, GASOLINE 6A2-33
B. Locate the piston ring end gaps as shown in
figure 68. Lubricate the piston and rings with
engine oil.
C. Without disturbing the ring end gap Ipcation,
install J 8037 over the piston (figure 69). The
piston must be installed so the piston valve;
clearance notches face the top of the block (fig­
ure 70).
D. Place the piston in its matching bore. Use a
hammer handle to tap the piston down into its
bore. At the same time, guide the connecting
rod into position on the crankpin, using J 5329.
Hold the ring compressor against the block until
all rings have entered the cylinder bore.
| 9 | Important
• Each connecting rod and bearing cap should be
marked, beginning at the front of the engine. Cylin­
ders 1, 3, 5, and 7 are the right bank and 2, 4, 6,
and 8 are the left bank (when viewed from the front
of the engine). The numbers on the connecting rod
and bearing cap must be on the same side when
installed. If a connecting rod is ever transposed
from one block or cylinder to another, new connect­
ing rod bearings should be fitted and the connect­
ing rod should be numbered to correspond with the
new cylinder number.
CONNECTING ROD BEARING SELECTION
Connecting rod bearings are of the precision insert
type and do not use shims for adjustment. DO NOT
FILE RODS OR ROD CAPS. If clearances are exces­
sive, install a new bearing. Service bearings are avail­
able in standard size and 0.001 inch and 0.002 inch
undersize for use with new and used standard size
crankshafts, and in 0.010 inch and 0.020 inch undersize
for use with reconditioned crankshafts.
Use gaging plastic to measure connecting rod bearing
clearance. This wax-like material compresses evenly
between the bearing and journal surfaces without dam­
aging them. Proceed as follows. It is assumed that the
parts have been inspected as previously outlined.
Figure 71—Placing the Gaging Plastic on the
Journal
Clean (Figure 71)
• Oil from crankshaft journal and the connecting rod
bearing inserts.
0 Install or Connect
1. Connecting rod with the upper connecting rod bear­
ing insert to the crankshaft journal.
9
Important
• If a bearing is being fitted to an out-of-round
crankpin, be sure to fit to the maximum diame­
ter of the crankpiri. If the bearing is fit to the
maximum diam eter and the crankpin js
out-of-round 0.001 inch, interference between
the bearing and the crankpin will result in rapid
bearing failure.
2. A piece of gaging plastic, the length of the bearing
(parallel to the crankshaft), on the journal (figure
71). Plastic gage should be positioned in the mid­
dle of upper and lower bearing insert. (Bearings
are eccentric and a false reading could occur if
placed elsewhere.)
3. Connecting rod cap with the lower connecting rod
bearing insert. DO NOT TURN THE CRANKSHAFT
WITH THE GAGING PLASTIC INSTALLED.
N O T IC E : S e e “N o tic e ” o n p a g e 6 A 2 -1 .
4. Connecting rod bolt nuts.
Tighten
•Connecting rod bolt nuts to 66 N-m (48 ft. lbs.).
Remove or Disconnect
• Connecting rod cap.
• The gaging plastic will be found sticking either
to the journal or lower connecting rod bearing
insert. Do not remove it at this time.
Measure (Figure 72)
• Gaging plastic at its widest point* using the scale at
the gaging plastic envelope (figure 72).
— If the clearance exceeds specifications, select af
new, correct size connecting rod bearing and
remeasure the clearance.
— Do not attempt to use shims or file the bearing
to obtain the needed clearance.
— If clearance cannot be brought to within specifi­
cations, recondition, or replace the crankshaft.
Remove or Disconnect
• Gaging plastic.