GMC S Series 1994, Руководство по ремонту

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INITIAL TIGHTENING SEQUENCE
FINAL TIGHTENING SEQUENCE
A. Bolt 56 N-m (41 ft.lbs)
All Other Bolts 47 N-m (35 ft.lbs)
B7873
Figure 52— Intake Manifold Bolt Tightening
Sequence
3. Pushrods.
• Seat the pushrods into the socket of the
hydraulic lifters.
Important
•W h e n new ro c k e r arm s a n d /o r b a lls are
installed, coat their bearing surfaces with high
viscosity oil with zinc (GM P/N 12345501 or
equivalent).
4. Rocker arms (44) with balls (43) on to the proper
stud.
5. Rocker arm nuts (42) on to the studs.
• Align the push rod into the rocker arm while
tightening rocker arm nut (42).
Adjust
• Valves. Refer to “Valve Adjustment.”
VALVE A D JU STM EN T
The 4.3L VIN Z engine can be equipped with two
different rocker arm stud configurations that require dif­
ferent valve lash procedures.
If you have a 4.3L VIN Z engine that has screw-in
rocker arm studs with positive stop shoulders, no valve
adjustment is necessary. When the valve train requires
service, you simply tighten the rocker arm nuts to 27
N-m (20 ft. lbs).
If you have a 4.3L VIN Z engine that has pressed-in
rocker arm studs, you must follow the valve adjustment
procedure outlined below.
1. Rotate the engine until the mark on the torsional
damper lines up with the “ 0” mark on the timing
tab and the engine in the number one firing posi­
tion. This may be determined by placing fingers on
the number one valve as the mark on the damper
comes near the “ 0” mark on the timing tab. If the
rocker arms are not moving, the engine is in the
number one firing position. If the rocker arms move
as the mark comes up to the timing tab, the engine
is in the number four firing position and should be
turned over one more time to reach the number
one position.
2. With the engine in the number one firing position
as determined above, the following valves may be
adjusted:
• Exhaust valves 1 , 5 , 6 .
• Intake valves 1, 2, 3.
(Even numbered cylinders are the left bank; odd
numbered cylinders are the right bank, when
viewed from the front of the engine).
3. Back out the adjusting nut until lash is felt at the
pushrod, then turn in the adjusting nut until all lash
is removed. This can be determined by rotating the
pushrod while turning the adjusting nut. When the
play has been removed, turn the adjusting nut in 1
3/4 additional turn (to properly locate the lifter
plunger).
4. Crank the engine one revolution until the timing tab
“0” mark and torsional damper mark are again in
alignment. This is the number four firing position.
The following valves may be adjusted:
— Exhaust valves 2, 3, 4.
— Intake valves 4, 5, 6.
INTAKE MANIFOLD
INSTALLATION
Install or Connect (Figures 51 and 52)
1. Gaskets to the cylinder head with the port blocking
plates facing the rear of the engine.
2. RTV to the front and rear sealing surfaces on the
block. Apply a 5-mm (3/16-inch) bead of RTV (GM
P/N 1052366 or equivalent) to the front and rear of
the block as shown in figure 51. Extend the bead
13 mm (1/2 inch) up each cylinder head to seal
and retain the gaskets.
3. Intake manifold to the engine.
NOTICE: Refer to “Notice” on page 6A3-1.
4. Intake manifold bolts.
Tighten
Intake m anifold bolts to 47 N-m (35 lbs. ft.)
using the tightening sequence shown in figure
52.
Retorque, intake manifold bolts using the tight­
ening sequence shown in figure 52.
Bolt 9 (A in figure 52) to 56 N-m (41 lbs. ft.)