Abstract: A C-clip retainer is provided in a groove of a piston, such as for an engine hydraulic valve lash adjuster, to allow installation and removably retain the piston in a cylinder of an associated assembly. The groove has a novel shape including an inner surface that is angled relative to a longitudinal axis of the piston to provide a larger groove diameter at a first axial end surface and a smaller diameter at an opposite second axial end surface of the groove. Upon installation, the clip is urged into the smaller diameter, allowing easier installation, but upon removal the clip is expanded by forcing it to the larger diameter, thereby increasing the retention force on the piston. The first axial end surface may also be formed with a back angle that reduces forces of the associated cylinder edge that tend to compress the retainer into the groove, thus further increasing the piston retention force.

Abstract: A hydraulic lash adjuster for disposition between a rocker arm and a valve stem of an internal combustion engine comprises a body having an axially extending neck depending from a lower end thereof. An enlarged head portion extends from the terminal end of the neck and has a semispherical lower surface. A foot assembly includes a disk shaped foot with an upper surface, a lower surface and a cylindrical sidewall defining an outer perimeter. The upper surface has a socket configured to receive the enlarged head. The foot assembly further includes an inverted cup shaped retainer having a cylindrical wall and radial leaves extending inwardly from the upper end of the cylindrical wall, defining a central opening. The axially extending neck extends through the central opening and the opening has a diameter smaller than the enlarged head.

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.