installation and retention or removal of an hea or lash adjuster in a housing defining a cylinder will now be described to install the piston 74 in the baffle 66 the retainer 80 is first slid into place on the groove 78 of the piston the piston 74 is then inserted from the bottom of the baffle 66 as shown in fig4 so that as the piston is raised the retainer clip 80 first engages the entry angle a formed by surface 70 on the bottom edge of the baffle the entry angle cams the c clip 80 inwardly compressing it into the groove 78 while at the same time the clip is forced downward to engagement with the lower or second end surface 86 of groove 78 at this point the diameter of the inner surface 82 is at a minimum due to the slope of the groove assembly angle c thus the c clip is easily compressed into the groove and allows upward motion of the piston with a minimum of c clip force against the cylinder 68 this reduces the possibility of scratching or otherwise damaging the cylinder surface when the piston is fully installed as shown in fig4 attempted removal of the piston from the baffle requires downward motion of the piston relative to the cylinder 68 this causes the bore retention angle d formed by surface 84 to engage the retainer clip 80 forcing it upward in the groove 78 toward engagement with the upper or first end surface 84 by this motion the retainer clip reaches.