This unit has been tested and sealed at the factory and must not be tampered with in any way. Tampering of any kind will void factory warranty.
It is necessary that the engines on which lifters are to be installed have shut-off valves between the fuel header and fuel injection valve assembly.
The secondary springs under the rocker arm must be removed permanently on Cooper-Bessemer® engines.
Roll engine over until the valve is closed (low cam). Back off the tappet adjusting screw and install the push rod and hydraulic lifter.
Tighten the rocker arm adjusting screw, covering the bottom adjusting line on the lifter with the bottom of the adjuster cap. Wait 30 seconds, then loosen until the top adjusting line on the lifter is even with the adjuster cap. Wait for 30 seconds.
Again, tighten the rocker arm adjusting screw until the bottom adjusting line on the hydraulic lifter is covered by the lifter cap. Wait for 30 seconds. Loosen the rocker arm adjusting screw until the center line on the lifter is visible. Be sure that all jam nuts are tight. ** Repeat this sequence for each cylinder. ** Under normal conditions, no further adjustments are necessary.
Roll engine over one or two complete revolutions and check adjustment. If necessary, repeat sequence in Steps 3, 4 and 5.
Operate engine. If hydraulic lifters were set properly, tappet clearance will be "0." Balance each cylinder by adjusting gas cocks. It is suggested that the engine be started with the gas cocks set at 40% open. After balancing the engine and running approximately 10 to 15 minutes, re-check hydraulic lifters to see that the center adjusting line is even with the bottom of the adjusting cap. NOTE: Never adjust hydraulic lifters while the engine is running.
Lifter setting should be visually inspected from time to time. The upper adjustment line should not be visible nor should the lower adjustment line be covered by the cap. The hydraulic lifter is constructed so as to compensate for approximately .250" wear. The above condition requires readjustment of lifter train area. Valve seats, valve stems, valve faces, seat faces, rocker arms, rocker arm bushings and pins and adjusting screws should be inspected for wear. Engines should not be operated with over or under adjusted hydraulic lifters.
Wesco suggests that spare hydraulic lifters be stored in an upright position.