Engines designed to work with tappets cannot be run without them as it would not only deteriorate the engine quickly but will also compromise on the fuel mileage, and component maintenance cost.

What is the purpose of the tappets?

A tappet is most commonly a component in an internal combustion engine which converts the rotating motion of the camshaft into linear motion of the valves, either directly or indirectly. An earlier use of the term was for part of the valve gear in beam engines beginning in 1715.

Why do tappets need adjusting?

Why tappet clearance is necessary

It accommodates the thermal expansion of the valve's axis (spindle) that is caused by the heat of the ship's engine when in operation. It ensures the closing of the ship's valve regardless of temperatures and working conditions.