Combustion engine parts are essential components of an internal combustion engine, which is a type of engine that converts energy from burning fuel into mechanical energy. The camshaft, which is an 8-letter word, is a shaft with cams that actuates the valves in an internal combustion engine. The piston, a 6-letter word, is a cylindrical part that moves up and down inside the cylinder of an engine, transferring force from expanding gas to the crankshaft. Lastly, the TAPPET, also a 6-letter word, is a projection that works with a camshaft to open and close the valves in an internal combustion engine.