See Figures 1 and 2
REMOVAL & INSTALLATION
In-line 6 Cylinder
- Disconnect the negative battery cable.
- Remove the rocker arm cover.
- Loosen the rocker arm until you can rotate it away from the pushrod or remove the rocker arm completely, giving clearance to the top of the pushrod. If the rocker arms do not need to be removed for other service procedures, it easiest to leave the arm installed to the stud in order to prevent mixing them up during installation.
- Remove the pushrod. If you are replacing all of the lifters, it is wise to make a pushrod holder as mentioned under Cylinder Head Removal. This will help keep the pushrods in order, as they MUST go back in their original positions.
- Remove the pushrod covers on the side of the block.
- Remove the lifter(s). A hydraulic lifter removal tool (GM part No. J-3049 or equivalent) is available at dealers and most parts stores, and is quite handy for this procedure. A thin magnet may also be used in some cases to draw the lifters upward so you can get your hands on them. Do not grab the outside of the lifters using a pair of pliers or any sharp instrument.
- Before installing new lifters, all sealer coating must be removed from the inside. This can be done with kerosene or carburetor cleaning solvent. Also, the new lifters must be primed before installation, as dry lifters will seize when the engine is started. Submerge the lifters in clean engine oil and work the lifter plunger up and down.
- Install the lifter(s) and pushrod(s) into the cylinder block in their original positions.
- Pivot the rocker arm back into its original position. With the lifter on the base circle of the camshaft (valve closed), tighten the rocker arm nut to 20 ft. lbs. Do not over torque. You will have to rotate the crankshaft to do the individual valves.
- Replace the pushrod covers using new gaskets. Replace the rocker arm cover, using a new gasket or sealer.
See Figures 3 and 4
Valve lifters and pushrods should be kept in order so they can be reinstalled in their original position. Some engines will have both standard size and 0.010 inch oversize valve lifters as original equipment. The oversize lifters are etched with an O on their sides; the cylinder block will also be marked with an O if the oversize lifter is used.
- Remove the intake manifold and gasket.
- Remove the valve covers, rocker arm assemblies and pushrods.
- If the lifters are coated with varnish, apply carburetor cleaning solvent to the lifter body. The solvent should dissolve the varnish in about 10 minutes.
- Remove the lifters. On diesels, remove the lifter retainer guide bolts, and remove the guides. A special tool for removing lifters is available, and is helpful for this procedure.
- New lifter MUST be primed before installation, as dry lifters will seize when the engine is started. Submerge the lifters in clean engine oil and work the lifter plunger up and down.
- Install the lifters and pushrods into the cylinder block in their original order. On diesels, install the lifter retainer guide.
- Install the intake manifold gaskets and manifold.
- Position the rocker arms, pivots and retainers on the cylinder head.
- Properly adjust the valve lash or secure the rocker arm pivots, as applicable.
- Install the valve covers, connect the spark plug wires and install the air cleaner.
- Disconnect the negative battery cable.
- Remove the valve covers.
- Remove the rocker shaft assemblies.
- Remove the cylinder head(s).
- Remove the guide clamps and guide plates. It may be necessary to use mechanical fingers to remove the guide plates.
- Using GM tool No. J-29834 or another suitable lifter removal tool and a magnet, remove the lifter(s) through the access in the block.
- Coat the lifters with clean engine oil before installation. If installing new lifters, they must be primed first by working the lifter plunger while the lifter is submerged in clean kerosene or diesel fuel. Lifters that have not been primed will seize when the engine is started.
- Install the lifters in their original positions in the block. A lifter installation tool can be fabricated out of welding rod or similar gauge wire and may help.
- Install the lifter guide plate and guide plate clamp. The crankshaft must be turned two full rotations (720 degrees) after assembly of the lifter guide plate clamp to insure free movement of the lifters in the guide plates.
- Install the remainder of components in the reverse order of removal.
The pushrods must be installed with their painted ends facing UP.