Adjustable rocker arm stud swap in '92 3.1L

[cusideabelincoln]

Hey guys, I've just rebuilt the 3.1L engine in my 92 Lumina. I fired it up and let the engine idle for a bit and could hear some chattering. There was also a ticking sound at first, but I believe that was coming from the transmission since I did some work to it, and when I put more tranny fluid in the ticking went away. Could have also been a loose nut, but that's not my problem.

Anyway, after letting it idle the chattering continued. After a while, the engine just died like it either ran out fuel or air. I tried turning it over, but it would only fire a couple of times and die, like it was choking itself.

The rebuild was stock except I put in an aftermarket cam, swapped the rocker arm studs for adjustable ones, and put in Comp Cams 1.6 roller tip rocker arms.

This is my first engine rebuild, and I tried to follow everything by a Haynes manual as well as the instructions from Com Cams. However, when I took off the valve covers I found that 3 of the rocker arms had worn the nut looser than I had it. So I assume the engine was not firing because the 3 valves weren't opening. There may also have been other ones loose, but 3 of them were definitely in a position where the pushrod would not lift the rocker arm enough to open the valve.

My big question is this: Have any of you had any problems like this with adjustable rocker arm studs? Here is my experience with installing these studs and rocker arms:

I zero lashed them and added a half turn about 3 times because I was paranoid, and I also had some other people check over them for me except for the final time. A weird issue I noticed was a few of the nuts didn't go on the stud as tight as they did the first time I used them, while the other nuts did seem to lock down fine.

Is it not a good idea to tighten and then back off the nuts more than 2-3 times? All of the nuts were tightened and backed off at least 2 times, but some might have been done 4 times. Have any of you had trouble like this with adjustable rocker arm studs and nuts?

What's a good solution for this problem? Should I get new nuts? My dad suggested thread locker might work. That would certainly be the cheaper route.

Oh and my last question for those of you who have done the rocker arm swap: When you zero-lash and add a half turn, should you be able to wiggle the rocker arm a little from side to side? I noticed on 1/3rd to 1/2 half of my rocker arms would wiggle a bit from side to side while others would be tight (yes I did turn the engine over when I checked them.) Also is the zero lash procedure going to be the same since I got a different cam? Here are the specs:

A.R.I Pro-builder Phase 2

http://www.engine-parts.com/GMV6/28camspecs.html

Duration @ .050"
Intake: 204 | Exhaust: 214

Adv. Duration
Intake: 270 | Exhaust: 280

Lift
Intake: .420 | Exhaust: .443

Lobe Center
Intake: 107 | Exhaust: 117

Thanks guys.

[ForcedFirebird]

Adjustable rockers are what I am after on my 3500 heads. The trick is adjusting them properly. Yes, if you re-tightened them that many times, it could cause a problem.

since my gen1 3.1 needes to have the UIM and MIM removed for the adjustment process, I make sure they are adjusted properly while everything is apart, and is as follows...

Turn the pushrod as you are firs tightening the rocker nut. When you feel the slightest resistance on the pushrod, stop. Now crank it another 5/8's turn. The book suggests you go 3/4 or more, but the way I see it is there is less damage if the rockers are loose. When the rockers are too tight, then they have a tendency to stay open and you will burn your valves (carbon build-up on the back causing improper sealing).

Since you have rocker covers that can be removed while the intakes are on, you can follow the same procedure as a SBC, and do it with the engine running (I still like the previous mention of adjusting better).

[cusideabelincoln]

Hmm, I only went a 1/2 turn extra since the instructions said so.

However I have to take off the intake to turn the pushrods. I can access the rocker arms with the valve covers off, but it's impossible for me to squeeze my hand in and under the intake to turn the pushrods.

It is feasible for me to adjust them while the engine is running, except 2 of the rocker arm nuts are hard to access as the intake does get in the way and I may not be able to get a socket on it flush. I also have to have the engine rolled forward (since it sits sideways in the bay) to access the 1, 3, and 5 cylinders.

Thanks for letting me know not to re-use the nuts. Would thread locker be sufficient to keep the nuts from vibrating off the stud, or should I just buy new nuts?

[ForcedFirebird]

Are you sure they are the locking nuts? When you had them off, did they have a triangular shape in the center?

[cusideabelincoln]

I did not notice. However I did notice when I first used the nuts you had to use a good deal amount of force to turn them on the stud. You couldn't finger tighten them. However, a few of the nuts seemed to lose this resistance, even after I zero lashed and added 1/2 turn. These loose nuts felt like I could take them off with my fingers, using a socket as an extension.

[ForcedFirebird]

Did you measure the threads? 10mm and 3/8's will work together by cross-threading, but that's a longshot. You may have re-tightened them too many times? I have a set of locking nuts that have only been re-tightened once if you need them for cheap.

[cusideabelincoln]

Nah I didn't measure the threads. I used the nuts that came with the Comp Cam 1.6 rocker arms, and I'm using the ARP rocker arm studs.

[ForcedFirebird]

ARP has two types of studs. One is metric, and the other is to convert a 60* engine to SBC rockers. Do you have a part number?

[cusideabelincoln]

I don't have the part number on me right now. I think I still have the packaging laying on the floor of the garage, but the garage is 20 miles away at my parent's house.

[95Grand-Am]

How did you find the base on the camshaft? Maybe some of them were on a lobe when you adjusted them.

[geoffinbc]

APR Only Sells studs with 3/8" or 7/16" tops which is the after market norm. If you used the COMP rockers with stamped bodies designed for the 60 degree V6 and used the APR studs then you have put a rocker designed for 10MM studs on a 3/8" stud this is where all the racket was coming from because of the sloppy fit. It also sounds as if you cross threaded the adjusting nut.

If you have not damaged the threads on the rocker studs (I doubt you have) then keep them in. Go find yourself some early small block rocker arm pivots they should be quite cheep and drop them on. Then but the adjusting nuts from Crane COMP or ARP and use them to permanently set lash. They have a set screw in them that will not allow them to back off.

[cusideabelincoln]

By early small block, what years are you talking about?

Also how do you guys find the base circle? Can I just watch the lifters and tell, since that's what the instructions said to do.

[ForcedFirebird]

To adjust the valve lash :
1 . Put cylinder one to TDC (compression stroke)
2 . Adjust one, five and six intake valves
3 . Adjust one, two and three ehxaust valves
4 . Rotate the engine until cylinder four is TDC
5 . Adjust two, three and four intake valves
6 . Adjust four, five and six exhaust valves

To adjust the valve, slowly tighten the locking nut (make sure the pointed side of the nut is up) while you rotate the pushrod in your fingertips. When you feel the slightest resistance stop. Tighten the nut 3/4 turn, I like to go about 5/8's of a turn because more damage is done with them too tight that loose (can always re-tighten if needed).

When locating TDC of either cylinder four or one, make sure the timing mark is at "0" on the compression stroke.

Any small block that had 3/8's locking nuts on them.

[cusideabelincoln]

One instruction set I had said to to something different.

To adjust the intake valves, I had to turn the engine over (for each cylinder) until I begin to see the exaust lifter (for that cylinder) rise.

To adjust the exhaust valves, it said to watch the the intake lifter to rise and then rotate the engine an extra little bit. Either a 1/2 or 2/3 turn, I don't remember now.

I'll post the detailed instructions when I go back to the garage.

[cusideabelincoln]

Well I found the packaging for the studs and the sticker says: 100-7201 GM 60-Deg V6 Rocker Stud Kit.

Are you sure ARP only makes standard? This site:

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_744892_-1_11519

looks like it has the 10mm ones for sale. However the product number for both the 7/16" and M10 are the same. Weird.

Also here are the instructions my rocker arms came with:

"...turn the engine over by hand in the direction of its running rotation until the exhaust pushrod begins to move upward to open the valve. This ensures that the lifter is on the base circle, and the intake valve is ready to be adjusted.

Tighten the adusting nut until all the slack is taken out of the rocker arm and pushrod. By lightly turning the pushrod with your fingers as you tighten the adjusting nut, you will discover or feel a point at which there will be slight resistance. At this point, you have taken all the excess slack out of the pushrod. You are now at what we refer to as zero lash. Turn the adjusting on-half turn more. This will give you the ideal preload of the rocker arm, pushrod, and lifter. Following this procedure, carefully adjust all intake valves.

To adjust exhaust valves, turn the engine over until the intake pushrod moves all the way up. Rotate past maximum lift, approximately 1-half to two-thirds of the way back down. The lifter is now on the base circle and the exhaust valve can be adjusted. Rotate the exhaust pushrod... blah blah zero lash... turn the adjusting nut one-half turn more. Go through exhaust valves and repeat this procedure carefully."

Is this method not as good as the other one? Should I just watch the lifters? When the lifter is all the way down I can adjust the rocker arms, right?