Hydraulic Lifter Preload Trouble on 68 289

[Rev]

Are you certain that you have hydraulic lifters? If you do have mechanical lifters any preload at all would leave the valves open when they should be closed and cause the engine to barely run.

The preload on the hydraulic lifter settings is just caused by pushing the push rod slightly down against a small spring in the lifter. After the engine starts up the oil pressure keeps the lifters pumped up to the proper level for a zero valve lash adjustment. The only advantage to the hydraulic lifter is that the "hydraulic adjustment" is automatic so you don't need to adjust very often.

Once you do adjust with the afore mentioned prerload (1/4-3/4 turn when the lifter is on the base circle of the cam), you should not need to do it again and again.

Try it as Ryan suggested. Also make sure you do actually have a hydraulic lifter cam.

Rev