US Patent 7412952 Poppet valve operating system for internal combustion engine

A poppet valve operating system for an internal combustion engine includes poppet valves which are driven by rocker arms rotationally mounted to a rocker shaft. Each of the rocker arms is maintained in axial alignment upon the rocker shaft by a separate, resiliently biased telescoping pin housed in the rocker arm body. The rocker arm pins extend into indexing reliefs formed in the outer cylindrical surface of the rocker shaft.