Rear Crankshaft Oil Seal Retainer Replacement; Measuring Camshaft Lobe Lift - GMC G Service Manual

6A4-18 SMALL BLOCK
REAR CRANKSHAFT OIL SEAL
RETAINER REPLACEMENT
H Remove or Disconnect (Figures 20 and 22)
1. Transmission. Refer to TRANSMISSION AND
CLUTCH (SEC. 7).
2. Clutch and flywheel or flexplate, as equipped. Refer
to TRANSMISSION AND CLUTCH (SEC. 7).
3. Oil pan. Refer to "Oil Pan Replacement" in this
section.
4. Screws (80) and nuts (81).
5. Seal retainer (82).
6. Gasket (84).
7. Rear crankshaft oil seal. Insert a screwdriver into the
notches provided in the seal retainer and pry the seal
out (figure 20).
IS iP I
Clean
• Gasket surfaces on block and seal retainer.
Install or Connect (Figure 22)
• Whenever the seal retainer is removed, a new
retainer gasket and rear crankshaft oil seal must be
installed.
1. Gasket (84) to the block. It is not necessary to use
sealant to hold the gasket in place.
2. Seal retainer (82).
3. Screws (80) and nuts (81).
E & l Tighten
• Screws (80) and nuts (81) to 15.3 N*m
(135 in. lbs.).
4. Oil pan. Refer to "Oil Pan Replacement" in this
section.
Figure 22 — Rear Crankshaft Oil Seal Retainer
5. Rear crankshaft oil seal. Refer to "Rear Crankshaft
Oil Seal" in this section.
6. Clutch and flywheel or flexplate, as equipped. Refer
to TRANSMISSION AND CLUTCH (SEC. 7).
7. Transmission. Refer to TRANSMISSION AND
CLUTCH (SEC. 7).
MEASURING CAMSHAFT
LOBE LIFT
Tool Required:
J 8520 Cam Lobe Lift Indicator
1. Remove the rocker arm. Refer to "Rocker Arm and
Pushrod Replacement" in this section.
2. Refer to figure 23. Position the dial indicator (part of
J 8520) so the plunger rests on the pushrod end, as
shown. Make sure the pushrod is in the lifter socket.
3. Rotate the crankshaft slowly in the direction of normal
rotation until the lifter is on the heel of the cam lobe.
At this point, the pushrod will be in its lowest position.
4. Set dial indicator on zero, then rotate the crankshaft
slowly, or attach an auxiliary starter switch and
"bump" the engine over, until the pushrod is in fully
raised position.
I ? | Important
• Whenever the engine is cranked remotely at the
starter with a special jumper cable or other
means, the distributor primary lead or coil pri­
mary leads should be disconnected.
5. Compare the total lift recorded from the dial indicator,
with "Specifications" at the end of this section.
6. If camshaft readings for all lobes are within specifica­
tions, remove dial indicator assembly.
7. Install the rocker arm and adjust the valves. Refer to
"Valve Adjustment" in this section.