Fastbird93

The way I set them this time was by moving the pushrod up and down until the slack was taken out. At the point where the slack was taken up (I.E. no up/down movement) I set the pre-load to 1/8 turn. The lifters are the same Comp R lifters that were in my motor before the rebuild. They were soaked in oil prior to installation in the new motor.

This was all done after the motor had been brought to operating temp. I've got the burn marks to prove it.

I just absolutely do not understand why I can't accomplish a task as simple as this.

My findings are this: If I do a cylinder by cylinder setting when cold, I end up with several rockers that are so loose at various points on the crankshaft rotation that when actuated they actually have room to move up and down on the stud.

I have no ability to do the engine running method.

With the motor having been heated up to operating temp, they're way too tight via the same lash technique.

They're ALWAYS noisy.

No collapsed lifters, geometry is good, cam is really agressive with the lobe ramp rates, but nothing extrordinary.

Plainly, WTF.

LT4orbust

I don't know what else i could suggest , i would have to see it to figure this one out. are the studs the correct size for the rockers? maybe if you give another rundown of what you replaced or changed . i didn't recongnize some of abreviations you gave earlier soo... be specific, somebody will know....hopefully !! one afterthought... you should be ok to go a full turn after zero lash...the 1/8 turn your giving probably isn't good enough...i think you have to be right at the very lowest part of the lobe for 1/8 turn to work and thats just too much work for what your doing, afterall they are hydraulic lifters they will compensate.

Fastbird93

The Studs are ARP 7/16" studs.
Comp Pro Mag NSA 1.6 Rockers, 1305-16
Comp High Tech Chromemoly Hardened 7.200" Pushrods
GMPP 14011051 Guideplates
Custom One Off Joe Overton Cam

Geometry checks out fine, double checked yesterday with a pushrod length checker.

Some hindsight: On my initial attempts to set the lash, the car was cold, had not been warmed up or started for at least 24 hours. I would set each set of valves with each cylinder at Top Dead Center (TDC). I do know that they're going to be semi-loose as you rotate the crank around, but some showed to be loose to the point of 1/4-1/2 inch movement up and down, which doesn't seem right. Set the entire motor, start up, and get horrendous clacking. I ran it yesterday with a valve cover off, and you could actually visibly see 4 rockers on the driver side (only one without cover) moving up and down on the stud as the rocker was being actuated. I wasn't getting any oil squirting initially, but as the motor warmed up it started to squirt.

Yesterday, I tried to set the lash with the motor running. I didn't stand a chance. I just couldn't tell between all the clacking which rocker was making the noise. Gave up on that real quick.

Yesterday after the motor running attempt, I went through and did the GM Service technique of setting various Intake and Exhaust valves and then rotating the crank one turn and setting the others. Seemed like that was going along fine, and I set them to 1/8 turn. Started the car, and everything was too tight! The car would barely idle.

So, is it more advisable to try to set them with the motor warmed up or cold?? I know any of the three methods work, but am I missing anything???

grygst76

Have you thought about the valve spring height? What size locks? 7 degree or 10 degree? Stock pushrod length is actually 7.195. If you tried everything to get the rockers adjusted try buying new studs and absolutely make sure the pushrods are correct...If you are using 7 degree locks those pushrods might be a little too long for your setup. I'm running a 306 cam with 987-16 springs and 10 degree locks with stock rockers and stock length pushrods and I have zero adjustment problems...

Fastbird93

I see what you're saying, but the problem is that the setup was essentially the same prior to the motor replacement and worked FINE. The only change other than the cam was a move from SA to NSA rockers.

grygst76

Why did you go with NSA? Are the studs 3/8 or 7/16th? It is a possibility
you have 3/8 studs with 7/16th rocker arms or vice versa and that is why it slides on the stud

Fastbird93

The Studs are 7/16 ARP studs. The Rockers are the 7/16 stud 1305-16 Comp Pro Mags.

I went with the NSA because of the agressive cam and the fact that I had 6 of the SA rockers jump off the valve stem (to the side, too loose) and chew off the self alignment tab. I decided that it would be better off to move to the NSA as the motor should be revving to 6500+ and making a pretty decent amount of power.

Fastbird93

Ok, I remembered the long thread about adjusting for Comp R's and dug it up.

I think I found my problem. I was setting it cold, and the recommendation was for at operating temp. I'm going back in tonight (for the millionth time) and am going to run the temp up and then set them to a zero lash and try my luck.

Reason I'm shooting for zero is because I'm expecting to rev upwards of 6500 with my setup.

Thanks for the help everyone, keep your fingers crossed please!

shoebox

It should still run ok after setting it cold, it just may not be perfect. Good luck.

LT4orbust

I can see setting lash with solid lifters at running temperature , hyd will find their own 0 lash as long as you get them close, where did you get the 1/8 turn info? if your valve to piston clearance is real close 1 turn might be too much with the engine running method, i take it you didn't try the 1/2 to 1 turn

Fastbird93

Someone's smiling on me, and laughing at the same time.

I went through one more time this morning, setting the lash at the comp recommended setting of .02-.04, using mindgames calculations for a 7/16" stud. I noticed that as the motor was being cranked around, some of the rockers were loosening, which is normal. What I found odd was that they were loosening to the point of vertical movement in the rocker.

So, I finished, and fired the motor with the valve covers off. About 3-4 rockers on each side had visible up/down movement on the stud, so I said screw it, and went to town with the motor running. I couldn't really tell one clack from the other, so I used the rocker movement as a guide, tighten until I don't see any more vertical movement out of the rocker. Well, this seemed to be doing the trick! It started to quiet down, and the cam started to lope like a **** at the prescribed idle unlike before.

I was getting it down, but had a mystery clacking on the driver side that was horrid, but couldn't see anything. So I grabbed a 3/8 ID hose and stuck it to each retaining nut, and when I got to the number two intake, I could plainly hear it. So I back it off to reset it, and the clacking goes intermintent, then almost silence, and then.....

The motor dies. Battery ran out of juice. Oh well...........Looks like my next chance to play is going to be on Tuesday.

Thanks for the help everyone, I think it's finally starting to happen.

Bersaglieri

How does the story end? Does the Joe O cam roar to life or does the LT1 rest in peice after valvetrain fatigue?

Just having some problems with mine and diggin up old stuff, wondering how it worked out.

Do you think that the running method is the most accurate?

-Dustin-

shoebox

Hasn't that subject been beat to death?

Bersaglieri

Well just seeing as how he did basically all of them, I wanted to know what method he thought helped him the most through such a tough rocker adjustment. Sorry

-Dustin-

shoebox

It's a pretty old thread. He might have forgotten what happened.

I wasn't trying to bust your chops. It's just that the rocker adjustment thing has been discussed over and over.