Valve Train Components; Cylinder Head - GMC 1989 Light Duty Truck Repair Manual

VALVE TRAIN COMPONENTS

PUSHRODS, ROCKER ARMS, BALLS, AND NUTS
| V | Clean
• Parts in solvent. Blow dry with compressed air. Make
sure the oil passages in the pushrods are clear.
Inspect (Figure 4)
— Rocker arms (13) and balls (12)
surfaces. These surfaces should
free from scoring or other damage.
— Rocker arm areas which contact the valve stems,
and the sockets which contact the pushrods (20).
These areas should be smooth and free of damage
and wear.
— Nuts (11). The nuts are prevailing torque nuts. At
least 6.2 N-m (55 in. lbs.) torque should be required
to thread the nuts onto the rocker arm studs. If not, it
is possible that the nut(s) could back off during
engine operation, causing loss of lash and valve
train noise.
— Pushrods for bending. Roll the pushrod on a flat
su rfa ce to dete rm ine if it is bent. R eplace if
necessary.
— Ends of the pushrods for scoring or roughness.
HYDRAULIC LIFTERS
Refer to GENERAL ENGINE MECHANICAL (SEC. 6A).

CYLINDER HEAD

DISASSEMBLY
Disassem ble (Figures 34, and 35)
Tool Required:
J-8062 Valve Spring Compressor
1. Valve keys (15).
• Compress the valve springs (19), using J-8062
(figure 35).
• Remove the valve keys.
• Remove the tool.
2. Rotators (17), and shields (18).
3. Valve springs (20) and dampers (240).
4. O-ring seals (16) and seals (19).
Figure 33— Installing the Oil Pump Screen and Pipe
at their mating
be smooth and
4.8 LITER L6 6A4-19
Seal
S p rin g
15. Valve Key
In ta ke Valve
16. O -ring Seal
17. R o ta to r E xh a u st Valve
18. D am pe r
S h ield
Figure 34— Valves and Components
Figure 3 5 — C om pressing th e V alve S prings
B-09438
B-07999
B-05284