Measuring Camshaft Lobe Lift; Camshaft Replacement - GMC G Service Manual

A. Forward
B. Fabricated Tool
C. Oil Seal Lip
82. Crankshaft
90. Upper Seal Half
91. Lower Seal Half
92. Main Bearing Cap
Figure 21 — Installing the Rear Crankshaft Oil Seal
MEASURING CAMSHAFT
Tools Required:
J 8520 Camshaft Lobe Lift Indicator
1. Remove the rocker arm as outlined previously.
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 rota­
tion 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.
] Important
• Whenever the engine is cranked remotely at the
starter, with a special jumper cable or other
means, the primary leads should be discon­
nected from the distributor or ignition coil.
5. Compare the total lift recorded from the dial indicator
with specifications.
6. If camshaft readings for all lobes are within specifica­
tions, remove dial indicator assembly.
7. Install the rocker arm and adjust the valves as previ­
ously outlined.
F-02380

CAMSHAFT REPLACEMENT

Remove or Disconnect (Figures 24, 25,
and 26)
Tool Required:
1. Battery negative cable.
2. Engine cover (G-Van).
7.4 LITER V8 6A5-15
LOBE LIFT
J 1619 Crankshaft Sprocket Puller