Lifter / Lash Adjuster: Service and Repair

Fig. 8 Exploded view of flat type hydraulic valve lifter:

Fig. 8A Exploded view of roller type hydraulic valve lifter:

Failure of an hydraulic valve lifter, Figs. 8 and 8A, is generally caused by dirt or an inadequate oil supply. 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 the oil is an unlikely cause of failure of a single unit.
The valve lifters may be lifted out of their bores after removing the rocker arms, push rods and intake manifold. Adjustable pliers with taped jaws may be used to remove lifters that are stuck due to varnish, carbon, etc. Fig. 8 illustrates flat type of lifter used. Fig. 8A illustrates roller type of lifter used. Roller type lifters are used to reduce friction and improve performance. The lifters are cylindrical with the exception of two parallel flats milled into the upper part of the body. Slotted guides which hold the lifters in pairs fit over the milled area to keep the lifters from turning in their bores.