Camshaft Replacement - GMC G Service Manual

CAMSHAFT REPLACEMENT

M Remove or Disconnect (Figures 24, 25,
1 and 26)
Tool Required:
J 5825-A Crankshaft Sprocket Puller
1. Battery negative cable.
2. Engine cover (G-models).
3. Air cleaner.
4. Grille (G-models).
5. Air conditioning condenser (if equipped). Swing it for­
ward from its mounting (G-models). Refer to AIR
CONDITIONING (SEC. 1B).
6. Fan, shroud, and radiator. Refer to ENGINE COOL­
ING (SEC. 6B1).
7. Rocker arm covers. Refer to "Rocker Arm Cover
Replacement" in this section.
8. W ater pump. Refer to ENGINE COOLING
(SEC. 6B1).
9. Torsional damper. Refer to 'Torsional Damper and
Front Crankshaft Seal Replacement" in this section.
10. Front cover. Refer to "Front Cover Replacement" in
this section.
11. Distributor. Refer to ENGINE ELECTRICAL
(SEC. 6D).
12. Intake manifold. Refer to "Intake Manifold Replace­
ment" in this section.
13. Pushrods. Refer to "Rocker Arm and Pushrod
Replacement" in this section.
14. Hydraulic lifters. Refer to "Hydraulic Lifter Replace­
ment" in this section.
SMALL BLOCK 6A4-19
15. Fuel pump and pushrod (carbureted engines).
• Align the timing marks (Figure 24).
16. Camshaft sprocket bolts.
17. Camshaft sprocket and timing chain. The sprocket is
a light interference fit on the camshaft. Tap the
sprocket on its lower edge to loosen it.
18. Crankshaft sprocket (if required). Use J 5825-A
(Figure 25).
19. Front engine mounting through-bolts.
NOTICE: When raising or supporting the engine
for any reason, do not use a jack under the oil
pan, crankshaft pulley, or any sheet metal. Due
to the small clearance between the oil pan and
the oil pump screen, jacking against the oil pan
may cause it to be bent against the pump
screen, resulting in a damaged oil pickup unit.
• Raise the engine.
19. Camshaft.
• Install two or three 5/16-18 bolts 100-125 mm
(4-5 inches) long into the camshaft threaded
holes. Use these bolts to handle the camshaft
(figure 26).
• Pull the camshaft from the block. Use care to
prevent damage to the camshaft bearings.
Cleaning, Inspection and Repair
Clean, inspect and repair or replace the camshaft and
related components, as outlined in the 1988 Light Duty
Trucks Unit Repair Manual.
The unit repair manual also describes camshaft bearing
replacement.