Hello,

81 vette 5.7.
On this particular engine, is it 1/2, 3/4 or 1 full turn on the rocker arm nut after you have backed it off until clatter and tightened until there is no clatter.
If the rule is, lets say 3/4, after you reach this and still hear a bit of a tick, is it safe to go a bit more until it is quiet? What would the extra maximum turn be?

I have a tick in the valve train. If this adjustment does not fix the tick by following the 3/4 turn theory, i should at least be able to find the particular rocker that is making the noise and then inspect the rocker and push rod for damage.

I have already checked for the simple "could Be's" like fuel pump, header leak etc.
Using a mechanics stethoscope, i know it's in the valve train somewhere.

Any feedback would be very appreciated.

Thanks

007.

 

You must change the adjustment slowly, so that the hydraulics can stabilize. Tighten until clatter stops; slowly tighten 3/4 turn more. Go to next valve.

If you still have noise on a lifter, then there is a problem with the lifter, rocker arm, pushrod, spring(s) or valve.

 

I go a quarter turn across the entire train, the back across another quarter, then finish with an eighth to a quarter what ever I'm comfortable with regarding that particular engine.

 

Hey Guys,

Thanks for your suggestions. Up to one full turn is safe? That is nice to know.
That being said... is it okay to be different on each rocker as required to have everything quiet, as long as you are very close to the one full turn limit? (eg. 3/4 to 1.1.

007

 

IT sure can be messy. I've used deflectors, cut holes in rocker covers (seems to be the best, least messy way), and just used old rags. I've seen oil squirt out of a pushrod/rocker arm and hit the wall in the garage. Seen lots that just barely dripped too. Ya' spins the wheel and ya' takes yer chances.

 

I have a set of rocker covers with the tops fabbed to help with the oil issue. I also picked up a set of tabs.
Hope all goes well.

Thanks for your replies.

007.

 

You can buy oil stoppers that attach to the rocker arms that plug the oil hole that either stops the oil flow or keeps it to a minimum. For the time it takes to adjust a bank of rockers there is still enough oil to keep them lubed up.
I have them, but rarely use them. I shop towel up the area and get it done. Before gloves were around to work on cars the hot or warm oil on the hands and arms was the biggest issue.

 

Run the engine long enough to get it to operating temperature before removing the valve covers to adjust the hydraulic lifters. Adjust the idle speed to as slow as the engine will keep running. Doing so will minimize oil squirting all over yourself or your garage walls.

I agree, there's a definite problem if you still hear ticking once the lifters are properly adjusted. Time to investigate the cause.

 

So is it "better" to do this with the engine running as opposed to doing half, then spinning the engine and doing the other half with the engine off?

 

So my cam says 1/2 turn from zero lash, would that be the rule while running also? 1/2 turn after the clattering stops?

 

If you do this and still have ticking your problem is not valve adjustment.

 

I can't believe anyone still adjusts hydraulic lifters with the engine running....

 

I was just asking.... Gonna use Lars paper tomorrow to adjust mine.

 

Not pointed at you - just in general.

Too easy to do with the engine off and comfortable vs. the instanity of clips and cut valve covers. I don't know of a single engine builder that does it running any more. The companion cylinder method makes it even easier:

http://www.carcraft.com/howto/ccrp_0...aft/index.html

Under a tree, in a remote corner of the earth, there is a guy adjusting his hydraulic valve lash with the valve cover off and the engine running. Yes, it's true. We've seen it. Proof is that you can buy valve covers with the tops cut off so that very same guy won't get oil sprayed all over his headers and T-shirt. At the same time, dyno shops and engine builders are sending engines out into the world with the valve lash pre-adjusted. So what gives? How is it done? We will show you.

 

To the OP:

Since you think there may be a problem with one of the lifters, you should do a final check with engine warmed and running. It's the only way to know for sure if there is [or is not] a problem with a lifter that is still noisy after being set.

You could start with setting them all on a cold engine...if you are familiar with that process. That is always best, so that one of them isn't way out of adjustment when the engine is started.

For a cold engine, find 'zero lash' point and tighten an additional 1/2 turn. If you are working with a warm engine that is running, [slowly] tighten an additional 3/4 turn, once that lifter is quiet.

 

Here we go again....

 

or not....

 

take the pissin match offline

 

"Sticky" lifters typicaly happens when the piston inside the lifter (pictured below) gets stuck - usually prevented from reaching the top of it's travel in the lifter body, but sometimes just stuck in place with varnish or gunk. This opens clearance in the valvetrain - hence the ticking. If it's REALLY loud, then likely the spring is broken or the lifter is really, really stuck...and that's a call to R&R the lifter. Regardless of the preload, if the lifter isn't able to move freely throughout it's adjustment range, it needs to be fixed - more preload doesn't fix the problem or help with troubleshooting - it just may hide the symptoms. The quick fix is often to turn aside the rockers and squirt a little carb cleaner down the pushrod to get it directly into the lifter body. Just a bit - as it's a strong solvent - but this often helps. Follow that with a correct valve adjustment and you've done everything possible short of cleaning/replacing the lifters.



For the OP, in no factory service manual will you find anything about setting hydraulic lifter preload running - and you won't see an experienced engine builder or mechanic doing it that way. The practice started as it doesn't require finding zero lash for cold adjustment - so it's simpler and less error-prone for an inexperienced builder or mechanic. I did it myself when I was learning engines in the 70's...but I scrapped my cut valve covers a couple of decades ago It's also not necessary for the engine to be warm; an iron/iron engine valvetrain grows about .003 between warm and hot, and hydraulic lifters do not "pump up"; the limit of upward travel is created in the lifter body; being full of oil just makes it harder to set the preload. I see some careful edits along these lines...

The companion cylinder method I posted works exceptionally well and quickly

 

you know you guys should volunteer to write some tech articles and become forum tech contributors. probably be more productive than arguing

always more than one way to do stuff...I started the C5 DIY thread a couple years ago and we have multiple threads on how to do the same thing....never hurts to have more than one method.

just a suggestion