Well sounds like I may have a few of them that are loose. They aren't clacking by any means, kinda ticking noise. I'd almost want to blame the noise on a exhaust leak but I think I may add a 1/4 turn. Can I do that? Just loosen up the center lock part, then turn a 1/4 turn? Or do I have to start completely from scratch and do them one full turn this time?

I did the half and half method with 3/4 turn. Put about 350 miles on it. Perhaps before I attempt adjustment I will put it up on jackstands and see if its leaking by the collectors, but it really sounds like very slight clicking under the valve covers.

 

I'm going through same thing, but I only put a 1/2 turn past zero lash.. I am almost possitive you can just add a 1/4 turn more to them by just unlocking nut then turning, but I wouldn't do it without asking the same question, just to be safe.

 

Go through and check the manifold bolts maybe loose? My were at one point in time except it sound real raspy, a ticky noise is probably 95% a rocker arm. LT1s usually are really loud you should hear mine if you know what to listen for, its pretty loud i had to adjust them once there proform 1.6s. What kind of rockers arms do you have, are they poly locks. Basically overall, i think its easiest to take one valve cover off at a time. Have about a qaurt of oil ready when your done to, but listen for the rockers that are loose the most fill them see if they have play back and forth tighten those downa tad bit. Once you get the loose one's tightened go back and loosen them one by onetill you hear them start ticking, once you hear them tighten them till you can't hear then go a qaurter turn tighter. If you have stock rocker arms its way easier, poly locks suck *** but there nice.

 

on a side note are you happy with ngk tr55 i bought a set for mine and i dont notice much difference the response is better have you noticed anything different lt1z28. How did you manage to get the back plug out on the passengers side of the motor lt1z28

 

The rockers are 1.6 SA promags. Poly locks.

I just happen to be running the 55's also. I like those plugs, nice and cheap, you get the these aren't going to work speech by the parts store workers too, which is funny ****.

 

I had the whole top end tore apart and just got it all put back together yesterday so I can't really say how well I like the plugs compared to the stock ones. Considering the car runs and feels alot different now.. I've heard nothing but good things about them though!

 

To the original question, yes, you can simply add 1/4 turn of preload. That's assuming that ALL of your lifters had equal preload to start with.

 

Thanks, I adjusted them all the same the first time, 3/4 turn. Is there a tell tale sign of which ones might be loose? I figure if I do them all a additional 1/4 turn then they are all still equally adjusted, I'm sure that would only work in a perfect world though, why else would I have some loose now, unless all of them are slightly loose?

 

Are you using PolyLocks or the OE style "crushed thread" nuts? The OE style will only hold for an adjustment or two, as the upper threads no longer hold their "crush", whch is what holds them in place.

If you're using PolyLocks, for what it's worth, ARP recommends that the set screw be tightened to 22 ft/lbs, at least on their Polys.

 

Yes, polylocks. It would be nice to just set them at a torque spec, if this were the case though wouldn't Comp Cams have stated this in their instructions? Just my thought there.

 

don't over tighten them. You could lose compression

 

He means the pre-lash, not the set screws. You over-tighten the set screws, you break the screws!

 

You would think so, but I would hazard a guess and say that ARP simply used the general industrial spec for the thread of their poly-locks. I'm sort of side-stepping here, because I forget what the thread size is.

 

What kinda valve covers are you runnin, if stock with the 1.6rrs then maybe its hittin the covers, that what mine are doing. Otherwise I would start from scratch and back em off and go through them. And lt1's for some reason in my experience always have noisey valve trains, but who knows.

 

Yeah I might just start from scratch and do them one full turn this time. I clearanced my valve covers years ago for them, shaved support stuff on them down. Its louder than they were on the other motor, same rockers though, so I don't see much a difference.
I don't remember who it is, I think its the guy running the LPE motor, but when I was searching this topic awhile back it had been recommended to him by some high end engine builder to go no less than a full turn and that a turn and a half wouldn't be overkill. I think i will go for one full turn and start from scratch.

 

My Pro-Mags sound exactly the same with my 1/8" turn preload. I bought some thick aluminum valve covers to keep the noise in. I was told by a local engine builder to put a 1/2" turn preload on them and the sound would go away. At the same time I was told to put an 1/8" turn by my head porter and an engine/cam guy that I know assured me everything is fine and to just get the covers to keep the noise in. Everyone seems to have a different opinion on it so I really don't know the right solution.

 

Maybe this question should have been asked first...What kind of lifters do you have? Stock, the factory says 1 full turn down from "zero-lash", but a lot of guys go 1/2-3/4, just to delay pump up by a couple hundred RPM.

Aftermarket lifters may vary by manufacturer. For some silly reason, I put a set of Comp 875Rs in my car, 'cause I thought 1 or 2 of my OEs were getting a little noisy. Supposedly, the Comps were a "high performance upgrade", so I took the plunge.

Comp is adamant that they're designed to be set at 1/8 turn, NO MORE. The only problem is that little amount of pre-load is hard to accurately attain. And, the Comps are a little noisy too, so I tried 1/4 turn. It quieted them a bit, however I then talked with a Comp tech rep, and he went nuts because I A) had them "cranked down" that much; and B) Set them with the engine running.

With respect to A) He said the 875Rs are a "limited plunger travel" lifter, so they don't have the same amount of plunger travel as an OE lifter. Therefore 1/8 turn is MAX, otherwise you could "jam" the plunger into the base of the inside of the lifter. Regarding B) The Comp tech rep then lectured me on how backing the adjuster off with the engine running brings the plunger in contact with the retainer clip, posing the possibility of dislodging the clip. WELL..... MILLIONS of gear heads have been using that method on SBCs, for well on 50 years without issue, so I basically ignored him on that point. He felt that you should bump the motor, get the cam on the base circle, slowly turn down the lock nut, find "zero lash", then go the 1/8 turn, repeat for the other 7 cylinders.... OBVIOUSLY, he'd never worked in the spacious engine compartment of a 4th gen F-bod.....

 

Stealth....Did you get some time yet, to get your valve train quieted down? This thought crossed my mind a couple of days ago, while I was aimlessly cutting my lawn...Is there any chance that your valve springs are too stiff for your lifters, causing the lifters to not pump up properly? I know it's a long shot...

 

Comp Cams help lines just blow my mind I've had my experiences with them...No I unfortunately haven't done anything with them yet since I haven't been home, its very frustrating! I really am unsure if my valve springs are too stiff for the lifters but I suppose its a possibility it has actually been in the back of my head for some time, yet it seems like a fairly common setup. I have the LS7's with PAC 1518's which are the CC 918's/PAC 1218's except that they are nitrided for added strength and have a .650" lift rating. I think I may just readjust the valves for the millionth time and put a 1/4" turn or a little more I dont know its been one real PITA!

 

Well in my case they are stock lifters. I was hung over yesterday, so I did what hung over people do. I didn't work on it but took video instead. I don't think they are really loose by any means, I suppose the video might have captured how its running.
Walkaround and it running at idle.

Then I tried to capture how it sounds while driving around, but mostly all you can hear is the gears screaming the whole time. If you let the video load and skip to the last minute and a half I have the hood open and I think it maybe a exhaust leak at the collectors, not sure. Driving around.