Rotation prevention structure of a valve lifter for an internal combustion engine

This invention relates to a valve actuating structure for operating poppet valves and more particularly to the rotation prevention structure of a valve lifter for an internal combustion engine. Several embodiments of anti-rotation devices for precluding rotation of the valve actuating lifters or tappet bodies caused by the action of the cam lobe on the engaged surface of the lifter. In each embodiment, the anti-rotation function is achieved without adding to the reciprocating masses of the engine.