Answer :
Final answer:
Common causes of tapping noise in an engine include valve clearance out of adjustment, worn rocker arm shaft, and loose exhaust manifold.
Explanation:
Valve clearance out of adjustment is a common cause of tapping noise in an engine. When the valve clearance is too tight or loose, it can create a tapping sound as the valves make contact with other engine components.
Worn rocker arm shaft can also lead to tapping noise. If the rocker arm shaft is worn, it may not be providing proper support and can create a tapping sound as it moves within the engine.
Loose exhaust manifold is another potential cause of tapping noise. When the exhaust manifold is not securely fastened, it can vibrate and produce a tapping sound as the engine runs.