GMC T Series 1994 Repair Manual page 550

Light duty truck unit
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3. Clamps (210).
Tighten
• Clamp bolts to 26 N-m (18 lbs. ft.).
Important
• After all clamps are installed, turn the crank­
shaft by hand 720 degrees (two full turns), to
insure free movement of the lifters in the guide
plates. If the engine will not turn over by hand,
one or more of the lifters may be binding in the
guide plate.
CO NNECTING ROD AND
PISTON INSTALLATION
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 (Yellow color identification), and
0.026 mm (0.001-inch) undersize (green color identifica­
tion).
Selective fitting of both rod and main bearing inserts
is necessary to obtain close tolerances. For this reason
you may use, for example, one half of a standard insert
with one half of a 0.026-mm (0.001-inch) undersize
insert which will decrease the clearance 0.013 mm
(0.0005 inch) from using a full standard bearing.
When using selective fit rod bearings, always use the
standard bearing in the connection rod, use the under­
size bearing in the rod cap. Also note that the color
coding for selective fit rod bearings are different from
the color coding for main bearings.
INSTALLATION
+«-
Install or Connect (Figures 69, 70, 71, and 72)
Tool Required:
J 8037 Ring Compressor
A. Make sure the cylinder walls are clean. Lubricate
the cylinder wall lightly with engine oil.
B. Make sure the piston is installed in the matching
cylinder. Install new pistons in the cylinders for
which they were fitted. Install used pistons in the
cylinder from which they were removed.
1. Connecting rod bearings.
A. Be certain that the bearings are the proper size.
B. Install the bearings in the connecting rod and
connecting rod cap.
2. Piston and connecting rod to the proper bore.
A. With the connecting rod cap removed, install
two short pieces of 10 mm ( 3/8-inch) hose onto
the connecting rod studs.
B. Locate the piston ring end gaps (figure 69).
Lubricate the piston and rings with engine oil.
C. Without disturbing the ring end gap location,
install J 8037 over the piston (figure 70).
A.
Oil Control Ring Expander Gap
B.
Second Compression Ring Gap
C.
Centerline Of Piston Pin
D.
Oil Control Ring Gap
E.
Top Compression Ring Gap
Figure 69— Ring Gap Location
D. The piston must be installed so that the depres­
sion in the piston crown is towards the outside
of the engine.
E. Place the piston in its matching bore. Using
light blows with a hammer handle, tap the pis­
ton down into its bore (figure 70). At the same
time, from beneath the engine, guide the con­
necting rod to the journal with the pieces of
hose (figure 71). Hold the ring compressor
against the block until all rings have entered the
cylinder bore.
F. Remove the hoses from the connecting rod
bolts.
Important
Each connecting rod and bearing cap should be
marked, beginning at the front of the engine.
Cylinders 1, 3, 5, and 7 are the left bank and, 2,
4, 6, and 8 are the right bank. The numbers on
the connecting rod and bearing cap must be on
the same side when installed in the cylinder
bore. If a connecting rod is ever transposed
from one block or cylinder to another, new con­
necting rod bearings should be fitted and the
connecting rod should be numbered to corre­
spond with the new cylinder number.
%
Measure
• Connecting rod bearing clearance. Refer to
SECTION 6A.
• Apply engine oil to the connecting rod bearings.
3. Connecting rod cap with bearing.
B8046

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S series 1994

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