The Stovebolt Site Forums The Shop Area Engine Shop Someone explain "lift loss" on hydraulic lifters

This a new one for me. I never even thought about it. It has something to do with the check ball in the lifter. As I vagly understand it, if you have no "lift loss" in the lifter from the ball closing too early then the push rod is to long and the valve opens early. This causes what would be a correct adjustment of the valve train to be too tight or no enough lash. Question is, what to do about it? Thanks

If the oiling system cannot fill a lifter fast enough, you would get "lift loss", or not enough lift inside the lifter to keep the push rod firmly seated in the lifter and rocker arm. This then would let the lash go to wide and cause rocker arm clatter. We used to call this valve float, since the whole valve train is in chaos.

If the lifter check ball sticks, then you could get full pump up or solid lifters and again the valve lash would go out of spec. only this time to little lash, thus holding the valves open.

Hydraulic lifters have a range of operation, the idea is for the oil inside to take up slack so the push rod is always seated snugly, yet when called upon to open the valve it does so without bleeding off.

Joe

Think of a hydraulic lifter like a shock absorber. Sorta.

O.K., from what I understand, I got it backwards. But now, what does one do about it? Change lifters? Could new ones be defective? Oil pump failing or clogged oil galley?
Another thing. This is a freshly rebuilt motor. Could the rebuilder installed a solid lifer cam instead of a hydraulic cam? Would that cause this sort of problem?
Thanks.

Is this happening on your project car? If so, the "what to do" is simply to put up with it. Those lifters were a very primitive design, and I don't think any upgrades are available. Maybe, "somewhere over the rainbow", there might be some new old stock parts, but brand new ones might have the same problem.
Jerry

Try adjusting them with engine running. On a V8 it's pretty easy, I have never done a older inline so I can't tell you how to do it. What could be happening is you are adjusting the lash when the lifters are bleed down. Once the oil pressure comes up, the lifters fill and hold the valves open.

If you are having running problems with uneven idle or vacuum gauge all over the place, then the lash is to tight and you a few valves open. Its better to be to loose then to tight. When the lash is loose, you hear the clatter of the valve train just as you would a solid lifter engine, but the vacuum should be pretty steady on the gauge.

Is it possible to put the wrong lifters on a hydraulic cam? I would bet it has happened more then once, but someone with more knowledge of the older engines will have to tell you that.

To check what you have, run the engine at idle with the valve cover off for a short time, enough to fill the lifters with oil. Then shut it off and quickly take a pry bar and see if you can compress the lifter. It won't be much, but you should be able to tell if the lash gets wider. Don't compress the spring and valve, press the rocker arm and pushrod down. If you find it will not move, chances are you have solid lifters. It could take a few minutes for the oil to bleed out, so give a little time while compressing it.

Joe