Valve adjustment question

[kxnomore]

I have been having some noisy lifters lately, so I decided today to try to tighten up the valvetrain, possibly for the first time ever based on the amount of effort to get the last traces of what used to be a cork gasket off the engine and valve cover.

But as I loosen the rockers up until they clack, and then tighten them until the clacking just stops, here is where my question begins.

How much further??? I was told 3/4 of a turn, but right at about a half turn, the engine noticibly changes pitch and kind of bogs down. Should I stop short of that happening and just go about a 1/4 turn??? or let the engine bog down a bit, and hope it recovers eventually???

Thanks in advance to any opinions or suggestions!

[68gmsee]

You need to make sure the lifters aren't collapsed. If they are you won't be able to adjust them like that.

But, to answer your question (there's going to be differences of opinion) I've always adjusted new lifter with the "tighten until clicking just stops and slowly turn 3/4 of a turn more" method.

I had a collapsed lifter that I adjusted once until I had minimal clicking and ran it like that for several years until I replaced them all.

[dave2953]

I believe the noise you're hearing is caused by the valve standing open. When I adjusted my valves I read countless threads on just what you're asking and everybody had a different answer. I did mine by sound, because I don't think you can necessarily say exactly 'x' amount of turn for each adjuster nut. You want to find a happy medium between the clattering and standing open. Hope this helps.

[larry may]

Well there you have it . If the lifters are not real good shape then adjusting the valves can be an aggravation. Generally I loosen them up till they chatter (one at a time) Then tighten it back down till the chatter stops. one fourth of a turn tighter at a turn till one full turn is accomplished. Take a minute or so to retighten. Did read some noise one time talking about turning the push rod while tightening the rocker just till some drag is felt while turning the push rod. Never tried that. May not work out either. Have fun

[Boog]

I believe the twist the pushrod while tightening mostly is for initial adjustment before startup. Or a cold adjustment it's sometimes called.
Most of the manuals I"ve seen called for warmed engine at slow idle and said to loosen until it clacks then tighten slowly until it gets quiet then turn an additional 3/4 turn for preload. The engine will slow down just a bit as the lifter compensates but will recover. Some will only accept 1/2 turn total and some will take 1 full turn. 3/4 turn has always worked very well on all mine.

[WorkinLonghorn]

The GM Service Manual says to THOROUGHLY warm up the engine before adjusting valves,then remove valve cover(s) install oil deflecters (I use a piece of cardboard laid along the head) and lossen until clacking.Then tighten until clacking just goes away and as mentioned in previous post above by larry may,tighten 1/4 turn at a time, wait ten seconds between turns (until engine again runs smoothly).GM says one full turn past zero lash.

[haysonj]

Originally Posted by WorkinLonghorn

The GM Service Manual says to THOROUGHLY warm up the engine before adjusting valves,then remove valve cover(s) install oil deflecters (I use a piece of cardboard laid along the head) and lossen until clacking.Then tighten until clacking just goes away and as mentioned in previous post above by larry may,tighten 1/4 turn at a time, wait ten seconds between turns (until engine again runs smoothly).GM says one full turn past zero lash.

The additional turn is to center the pushrod in the lifter

[kxnomore]

Thanks for all the tips. I ended up only being able to go between 1/4 turn and a half turn max. I couldn't tell if the engine was recovering while it sputtered and sounded like it was going to stall, so I backed off a bit until it neither clacked nor sputtered. Hopefully they are not too loose.

But they're practically silent now compared to before. You can barely hear them at slow speeds, and on the freeway the road noise is now louder than the lifters. Not too bad for an original engine with at least 115K miles!!!

[71big block]

I've found that with used lifters there is no exact way to adjust them, I use the tighten them until they stop clacking and the go a "little bit" more methode.

[larry may]

Originally Posted by WorkinLonghorn

The GM Service Manual says to THOROUGHLY warm up the engine before adjusting valves,then remove valve cover(s) install oil deflecters (I use a piece of cardboard laid along the head) and lossen until clacking.Then tighten until clacking just goes away and as mentioned in previous post above by larry may,tighten 1/4 turn at a time, wait ten seconds between turns (until engine again runs smoothly).GM says one full turn past zero lash.

Yip thats what I read 42 years ago. for hydralic.

[sickchevy68cst]

hmm i should try this out on my engine brb