Rocker arm definition
A curved lever that pivots in the middle. One end is attached to the top of the valve stem . In overhead-valve engines the other end is attached to the push rod . In some overhead-cam engines the other end is attached directly to the camshaft lobe. As the camshaft rotates, the rocker arms pivot causing the valves to open and close. Also see ball joint rocker arm and high lift rocker arms .