Valve Rocker Arm and Push Rod Replacement. GMC Truck GMC P42 Commercial Chassis 1997

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1997 🢒 GMC P42 Commercial Chassis 🢒 Engine 🢒 Engine Mechanical - 6.5L 🢒 Valve Rocker Arm and Push Rod Replacement

Removal Procedure

Remove the rocker arm cover. Refer to Valve Rocker Arm Cover Replacement.

Remove the rocker arm shaft bolts.

Important: Store and mark all the valve train components in the exact order to reassemble them in the same position from which they were removed.

Remove the rocker arm shaft with rocker arms.

Important: The pushrods must be installed in the original direction at assembly. This is because the pushrods have a different degree of hardness at each end. A paint stripe identifies the upper end of the pushrod. If the paint stripe is not visible, mark the pushrods on the upper end as they are removed.

Remove the pushrods.

Remove the rocker arms, if required.

5.1.	Insert a screwdriver into the rocker arm shaft bore. Break off the end of the nylon rocker arm retainers.

5.2.	Use a pair of pliers in order to remove the rocker arm retainers.

5.3.	Slide the rocker arms from the shaft.

Inspection Procedure

•	Inspect the rocker arms and the shafts at their mating surfaces. These surfaces should be smooth and free from scoring or other damage.

•	Examine the rocker arm areas that contact the valve stems and the sockets which contact the pushrods. These areas should be smooth and free of damage and wear.

•	Inspect the pushrods for bending. Roll the pushrod on a flat surface to determine if it is bent. Replace the pushrods if necessary.

•	Check the ends of the pushrods for scoring or roughness.

•	Inspect the hydraulic lifter guide plates and the clamps for damage.

Installation Procedure

Important: Lubricate the rocker arms with engine oil before installation.

Attach the rocker arms to the rocker arm shafts.

One type of rocker arm is used at all the locations.

Install the new rocker arm retainers by centering the rocker arms on the corresponding holes in the rocker arm shaft.

Use a drift at least 13 mm (1/2 in) in diameter.

NOTICE: The pushrods must be installed with the marked or painted end up. Failure to do so may result in damage or premature wear of the pushrod.

Install the pushrods.
Install the rocker arm shaft assembly.

Make sure the ball ends of the pushrods seat in the rocker arms.

NOTICE: Improper installation of the rocker arm shaft bolts may cause rocker arm shaft breakage and/or piston-to-valve contact.

Install the rocker arm shaft bolts.

5.1.	Rotate the engine until the mark on the torsional damper aligns with the "0" mark on the timing tab.

5.2.	Rotate the engine to the left 88 mm (3 1/2 in), measured at the torsional damper. This measurement can be estimated by aligning the torsional damper mark with the first lower coolant pump bolt. This procedure will position the engine so that no valves are close to a piston crown.

5.3.	Install both bolts snug on the shaft.

Tighten
Tighten the bolts to 55 N·m (40 lb ft).

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Install the rocker arm cover. Refer to Valve Rocker Arm Cover Replacement.