Its primary role is to convert the upward movement generated by the camshaft or pushrods into the precise downward force necessary to open the engine's intake and exhaust valves. Rocker arms are a centrally pivoting lever in an engine's valve train that transfers rod motion to open the valves of the engine. it is operated by a pushrod from the camshaft. It's a procedure that happens when these components come into direct contact with the tappets and by the shaft's movement. In an OHV engine the camshaft located within the engine block below the cylinder bank (s) pushes the pushrod. The rocker arm assembly serves as a crucial connection in the valvetrain mechanism.