Worn or loose followers, valve rocker arms

The follower, valve rocker arm, roller bearing should be intact and in the proper position.

Replace the followers, valve rocker arms, as required.

Stuck valves

Carbon buildup on the valve stem can cause the valve not to close properly.

Repair or replace as required.

Excessively worn or mis-aligned timing chain or chains

Replace the timing chain or chains and sprockets as required.

Worn camshaft lobes

Replace the camshaft or camshafts and SHLAs (valve lifters).

Sticking SHLAs (lifters)

Replace the SHLAs as required.