Tappets Common Faults and Repairs

What is it?

it is a small member interposed between each camshaft lobe and the valve lifting mechanism, or the valve itself, depending on engine design.

Where is it located?

Tappets for conventional-camshaft engines are usually of cylindrical or mushroom shape, about one inch long, and are located in guides machined in the engine block.

Indicators of faults:

This is caused by infrequent or missed oil and filter changes or the use of an incorrect grade of engine oil, causing oil starvation to the top of the engine or sludging of the cylinder head oil ways. The noise is due to sludged or worn hydraulic tappets/rocker arms or in the worst case, the damage will have affected the camshaft(s), this will probably be accompanied by a misfire or very erratic idle.

Common faults:

Ticking or tapping noise
Misfire (in extreme cases)