Abstract: A valve actuation assembly for an internal combustion engine is disclosed in which a rotatable rocker arm assembly is actuated by an engine driven camshaft to move a poppet valve reciprocably. The rocker arm assembly includes a hydraulic lash adjuster for disposition between the rocker arm and the valve stem. The lash adjuster includes an actuator at one end having an axially extending neck which terminates in an enlarged head. The enlarged head engages a foot assembly which includes a disk having a socket in which the head is positioned. A retainer ring is disposed in the socket and includes a wall portion which operates to establish an interference fit with the socket so as to fix the ring in the socket and a radially inwardly extending flange member which operates to define an opening through which the actuator neck extends but having a diameter less than that of the enlarged head portion of the actuator to thereby prevent removal of the head from the socket.