Worn or loose rocker arms

Replace the valve rocker arms as required.

Worn or bent push rods

Replace the push rods.

Sticking 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

Replace the timing chain and sprockets as required.

Worn camshaft lobes

Replace the camshaft and valve lifters.

Sticking lifters

Replace as required.