Lifter / Lash Adjuster: Description and Operation

Fig. 7 Hydraulic valve lifter components:

Hydraulic roller valve lifters are used on these engines. Lifter retainers and guide plates are used to keep the lifter from rotating on the camshaft. Failure of a hydraulic valve lifter, Fig. 7, is generally caused by an inadequate oil supply or dirt. An air leak at the intake side of the oil pump or too much oil in the engine will cause air bubbles in the oil supply to the lifters causing them to collapse. This is a probable cause of trouble if several lifters fail to function, but air in oil is an unlikely cause of failure of a single unit.
Valve lifters can be removed after removing rocker arm cover and pushrod cover. Loosen rocker arm stud nut and rotate rocker arm so that pushrod can be removed, then remove lifter guide, retainer and the valve lifter. It may be necessary to use tool No. J-3049 to facilitate lifter removal.