Hydraulic lifters

The hydraulic lifters are located under the valley gasket in the centre of the “V”.  The lower end of the lifter ride on the cam lobes (this is the part of the lifter that wears with time) and the upper end has the pushrod resting in it. A disassembled lifter has the following parts:

The distance between the Retaining Clip and the Pushrod cup is referred to as the “Preload”. Preload should be between 0.5 and 1.5mm

This is a lifter with 1.5mm preload. The pushrod cup has a distance of 1.5mm between the Pushrod Cup and the Retaining Clip. The brazing rod is used to “measure” the distance while the pusrod is in place with both valves closed.

This is a lifter with 0 preload. The pushrod cup is pushed right up against the Retaining Clip

To correct the pre-load, install (or remove) shims as needed between the head and the rocker pedestals (equal amounts under each pedestal on a head). Typically shims are between 0.3mm and 0.7mm thick depending on supplier. 

It is IMPERATIVE that the smaller hole in the shim be fitted over the oil feed hole in the head!!  Otherwise no oil will find its way to the rockers and the rocker shaft will wear very quickly! Click on picture to the right for better view

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