With the cam on the base circle and one hand on the pushrod, we tightened the retainer just until the pushrod wouldn't spin anymore. This allows you to adjust the valvetrain to a "zero lash" setting. To adjust the intake valve, first turn the engine by hand until the exhaust valve begins to open. This will ensure that the intake lifter is on the base circle of the cam. To adjust the exhaust rocker for a given cylinder, spin the engine until the intake valve fully opens and then begins to close.