REMOVAL & INSTALLATION
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 in. 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 rocker arm covers.
- Remove the 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.
- On models equipped so equipped (diesels, Oldsmobile produced engines and most 1987-89 engines with roller lifters), remove the lifter retainer guide bolts and the retainer.
- Remove the lifters. A magnet or a special tool designed for removing lifters is available, and is helpful for this procedure.
- New lifters must be primed before installation, as dry lifters will seize when the engine is started. On the diesel lifters, submerge the lifters in clean diesel fuel or kerosene and work the lifter plunger up and down to prime. On gasoline engine lifters, submerge the lifters in SAE 10 oil, which is very thin. Carefully insert the end of a 1 / 8 in. (3mm) drift or an old pushrod into the lifter and push down on the plunger. Hold the plunger down while the lifter is still submerged; do not pump the plunger. Release the plunger and the lifter is now primed.
- Coat the bottoms of the gasoline engine lifters, and the rollers of the diesel engine lifters with Molykote® or an equivalent molybdenum-disulfide lubricant before installation. Install the lifters and pushrods into the engine in their original order. If equipped, install the lifter retainer guide.
- Install the intake manifold gaskets and manifold.
- Position the rocker arms, pivots and bolts on the cylinder head.
- On the 231 V6, position and install the rockers and rocker shafts.
- For diesel engines, refer to the Rocker Arm Removal and Installation procedure earlier in this section for lifter bleed-down. New lifters must be bled-down on diesel engines; valve-to-piston contact could occur if this procedure is neglected.
An additive containing EP lube, such as EOS, should always be added to crankcase oil for break-in when new lifters or a new camshaft is installed. This additive is generally available in automotive parts stores.
- Once all valves are properly adjusted, install the rocker arm covers.