Install or Connect 1 . Valve lifters to the block. 2 . Valve lifter guide and bolts. Note previously made mark on the valve lifter guide. Reference mark should be pointing toward front of engine. Tighten • Guide bolts to 16 N·m (12 lb· ft.). 3 . Valve pushrods. A . Seat the valve pushrods into the socket of the valve lifters. B . Coat the mating surfaces of the valve rocker arms and balls with Engine Oil Supplement GM P/N 1052367 (or equivalent). 4 . Valve rocker arms with balls on to the proper stud. 5 . Valve rocker arm nuts onto the studs (figure 12- 88). Align the push rod into the valve rocker arm while tightening valve rocker arm nut. No lash adjustment is needed.
Tighten • Valve rocker arm nuts to 25 N·m (18 lb· ft.). Valve Adjustment The 4.3L engine 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 25 N·m (18 lb. ft.). Intake Manifold Installation Figures 12-89 and 12-90 Install or Connect 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 13 mm (1/2 in.) bead of RTV (GM P/N 1052366) or equivalent to the front and rear of the block as shown in figure 12-89.
Extend the bead 4 mm (5/32 in.) up each cylinder head to seal and retain the gaskets. 3 . Intake manifold to the engine. 4 . Intake manifold bolts. Tighten • Intake manifold bolts in three steps using sequence shown in figure 12-90. - Bolts in sequence to 3 N·m (27 lb. in.). - Bolts in sequence to 12 N·m (106 lb. in.). - Bolts in sequence to 15 N·m (11 lb· ft.). Rocker Arm Cover Installation Figure 12-91 Install or Connect 1 . New gasket. 2 . Valve rocker arm cover. 3 . Valve rocker arm cover bolts. Tighten • Rocker arm cover bolts to 12 N·m (106 lb. in.). G643 (E) Service Manual Chapter 3. Engine Mechanical System 105