Ok so my car has maybe 5 mins of idle time on it so far, I took the valve covers off just too see how everything was going on I noticed most of the rockers are hitting the studs..

This is the setup
LE cam
Comp R lifters
Comp guide plates
ARP 7/16 stud
1.6 Pro mags
Zero decked block
Trickflow 21* heads

So anyhow, When I was assembling the motor I didn't have a PR checker tool when I got too the valve train, I grabed one of my stock ones just too see how that would fair and using a stock lifter I made solid and turning the motor all the way over, the swipe was just about dead center. So I went ahead and installed my comp 7.2 pushrods.

This is still the case, swipe is dead center on most valves, how ever on maybe a few valves it leans just a slight amount too the left.. But I still have the problem of some rockers grinding on the stud..

Any ideas?







some pics of the swipe.

 

Were they installed with the flat side of the fulcrum up? How much preload was used on the rocker adjustment? What is the length of your push rods? Are you absolutely sure the rocker adjustment was done properly?

Here is quick pic of mine.....
http://www.ace1252.com/images/1996_L...mag_rocker.JPG

 

Fulcrum being the part thats flat for the nut to sit on right? yes that is up.

only a little preload the comp r lifters call for 1/16 turn.

7.2 pushrod length..

confident they where lashed right..

 

What heads are you running and what height are the valve springs installed?

 

the new lifters could of filled with oil which made your adjustments to tight and now they're rubbing i know when my car had over tightened rockers it scraped the bottom of all my rockers...

 

trickflow 21* heads with the springs that came with them out of the box.

 

I got a PR tool, about a 7.4 PR is still pretty center on the valve tip, slightly lower.. heres a pic.. Should I go for some bigger pushrods?

sorry for all my ****ty cellphone pics, hopefully you can see

 

I don't know if those heads would require that long a pushrod, but clearly the rocker is sitting too close to the bottom of the stud. We may have to have someone else with those heads chime in to see if they have the same problems and to check on what pushrod they used. It may not hurt to contact Trickflow and ask in "general" what pushrod length needs to be used.

I've always been gun-shy of the Comp R lifters....there has been a lot of trouble from them over the years on this board. I don't know if they could be playing into the issue or not, but you are going to have to look at the clearance at the bottom of the rocker closely.

Do you have a stock lifter to drop in and compare? The most clearance you will ever have is with the rocker simply resting on the pushrod and valve with the crank on the cam baselobe. This really is zero lash. If you were to screw on the valvelock, when it just touches the top of the rocker....you are at zero lash. It's critical that you have the crank in the correct position when adding the preload. If the rocker is touching the bottom of the stud at this point, something is wrong......but I honestly can't tell you if a 7.4" pushrod is unusual for a SBC. Going to have to get some of the more experienced engine builders on here to chime in.

What method did you use to adjust the rockers? For me, I find that it's not easy to adjust them unless I can see the top of the lifter and the plunger. I've always adjusted my rockers with the intake off. I just find it easier this way. Zero lash should not preload the lifter plunger at all. If it does, then you are not at zero lash....you are into preload. With the intake off, you can easily see if you are mistakenly preloading the plunger.

1/16th of a turn sure is touchy. I used new GM lifters on my build and went 1/2 turn on my preload. Last time I inspected them, no issues. Based on my picture, you can see that the rocker has plenty of space between the bottom of it and the stud. That picture was taken with rocker preload adjusted. I'll try to find a better picture that more clearly shows the clearance of the rocker to the bottom of the stud.....but seeing as I have stock LT1 heads(milled 0.005"-0.010") and you have Trickflow.....we are kind of apples to oranges with it.

 

Looks to me as though the rockers are dropping down on the stud too low and rubbing on the shoulder of the stud.


Since the movement is spot on at the valve, the only way to correct it would be to cut down the boss for the stud to drop the stud lower.

Also appears that the stud would have been low enough if the guide plate wasn't under it. Would these heads have been designed for SA rockers?

Could your problem be eliminated by removing the guide plates and going to SA rockers???????

Never actually looked for this but could there be studs of differing lengths (or different shoulder heights) depending on whether guide plates are used or not?????????

I would be curious.

 

I would verify that the "Comp guide plates" are, indeed, the correct ones for an LT1. If they happen to be ordinary generation 1 small block plates, they are possibly incorrectly aligned for an LT1 that has a slightly different off-set in the valve train and could be forcing the rocker to ride to one side of the valve. The sides of the pushrods and the guide plates should provide a witness mark if the whole valve train is misaligned. Isky adjustable two-piece guide plates are a solution to this problem. I have read that Trick Flow also produces an LT1-specific guide plate but I've never seen a set of those.

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What guideplate is right for the "LT1" has nothing to do with this since he has Trickflow heads. The heads dictate the guideplates.

I am not saying he has the right or wrong guideplates just offering the understanding necessary to figure out what he does need.

The use of guideplates is VERY common on LT1s be they stock or aftermarket heads so simply the presence of a guideplate is not the issue.

Were those studs used before this build?

Looks like a lot of "wear" on them from the trunnion if it is only 5 minutes of use.

The studs are 7/16" like the rockers right? I know you said they are but it almost looks like the whole rocker was maybe slapping around on the stud like it was too loose a fit? I could be way off the cell phone pics aren't great.

 

Statements to the contary notwithstanding, if the photo is indicative of how they were installed, the trunion was installed upside down. The milled recess in the trunnion faces up so should not be visible in the picture.

 

I noticed that too, but assumed he just spun it the other way before taking the picture. Maybe he can clarify.

 

He clarified that on another forum. He had just been spinning the trunnion during inspection.

 

I actually am not using the comp guide plates, I found them sitting on my table and remembered I put the trickflow guide plates that are included with the cylinder heads, They also say "UP" on them so they are installed correct..

Yes its a 7/16 stud and rocker, They are used but the wear on the stud is new from this build.

It really baffles me how some of them have wear and some don't.. I really wonder if its something to do with these lifters, I know they are picky..

Im going to try and take a video and ill update in a bit.