I've recently just swapped a 355 in my 91 camaro and I have a xr276hr with comps cam 1.52 roller rockers and I've just upgraded to a 1.6 scorpion rockers and can't seem to keep them tight. After some minutes of running the engine the valves don't clatter at all but after a little bit they become loose. I never had this problem with the 1.5 rockers. I've tried adjusting them with the engine running aswell and same thing happens and I've also repleaced the poly locks aswell and already had 3 jump the valve stem. Any ideas what could be the problem causing them to loosen? I have Blueprint h8002k heads that can handle .575 lift and also have screw in 3/8 flat top studs.

 

I see the heads come with guide plates. Is there interference where the pushrod passes through the cylinder head? Often, when increasing the rocker ratio, it's necessary to enlarge the pushrod opening otherwise there may be binding. Might be worth a look.
It's not necessary to get into your adjustment procedure as you say you didn't have trouble with it previously.
One other thing to look at is interference with the rocker and the valve spring. That may mess up what you think is proper lash but it isn't.
Just throwing a couple of ideas out there in case you may have overlooked them.
Another thought. Where your Comp rockers full rollers? Just thinking that the trunnion in the new rockers isn't orientated with the flat facing up so as to properly engage the poly lock.

 

Yes the heads originally came with guide plates but I removed them since I had the self aligning rocker arms, yes they were full roller rocker arms from comps cam. I bought hardened pushrods aswell and is what I'm using now just in case I decided to use the guide plates. There doesn't seem to be binding or rubbing anywhere. Do you think I would need to use the guide plates ? At first I was thinking maybe it's a lobe going flat but it's doing this on both sides and multiple valves and previously never had a problem with this so I'm starting to think it might be cause of the added lift on the new rocker arms. I read somewhere that it's not recommend to use guide plates with self aligning rocker arms aswell.

 

I doubled checked to make sure the flat part was up facing the polylocks aswell and still the same problem occurs I also checked to make sure the rocker arms seats perfectly on the stem aswell.

 

Are you tightening them by just cranking on the Allen?

 

 

The first time I installed them I did a 1/4 after zero lash then I tightened the poly locks. The second time I left it a little bit before a 1/4 then I tightened the poly all the way down and use a wrench and the Allen key together to give it a good snug. The third time I did 1/2 past zero lash and tighten the Allen key and wrench together really tight and right now I can hear the clattering but none of the rocker arms are loose. This Final time i tightened them down pretty good and when I first started up the engine it was smooth and quiet no clatter at all really but after a few minutes it starts up again and gets worse and worse.but none of the nuts or poly locks are loose. I was driving it last time and two rocker arms jumped the stems. I'm starting to think it could be a lifter problem maybe ? I checked the oil and it's all the way full.

 

One thing I see as a potential is the lack of thread engagement on the rocker stud. That set screw typically is about flush with the top of the poly lock. Could be a simple matter of just not enough thread to keep things together. The aluminium rocker is undoubtedly "thicker" top to bottom and as such sits up higher on the stud.
And only one method of push rod alignment is used. Either the heads (old school OEM), guide plates or self guiding rockers.

 

I wouldn't have guessed that from the post above.

Maybe removing one of the rocker arms and looking for any witness marks will reveal contact somewhere. It's like you have it secured well enough then it wears out.

 

I agree - I have the non self-aligning version of those same narrow body rockers on my Vortec heads and the set screws are slightly proud of the poly lock. Looks like your rocker studs are too short to me.

GD

 

I removed all the rocker arms and noticed one thing that the rocker arms have alot of movement side to side on the valve stem. Could this be the noise ? And also they were pretty tight when removing the nut and polylocks aswell. I also inspected the pushrods for and rubbing but they look perfect. I attached photos of the valve stems and rocker arms the valve stems look pretty good with no sign of wear except the ones that the rocker arms jumped off of. You can see the damage of the rocker arms and stem when it jumped .I also measured the rocker stud aswell, what length would y'all recommend for polylocks?

Thank you everyone so far for the help.

 

The damage from the rocker coming off notwithstanding, is that retainer contact I see beside one of the more heavily damaged rockers?
As for length, you'll have to take that measurement of yours and go through ARPs catalogue (my rocker stud of choice) or whoever your preferences is. I don't have my online catalogue handy at the moment. I've been down this road before you.

 

It looks like you have the equivalent of the 134-1701. The next longest, and one recommended for roller rockers is the 134-7104. That'll give you an additional .145" of stud length and 2/10ths more thread. Will that solve your problem? I think there are other issues but this is something worth addressing regardless.

 

I checked all the retainers and it seems that there's no damage anywhere else. I'm going to replace the studs and hopefully that fixes it but I'm not sure what else could be causing this problem.

 

Before you order new longer studs, IF YOU HAVE THE CLEARNCE, you can put a thick washer under your current stud to raise it up by the thickness of the washer.
I'm talking about a .120" thick hardened washer like your head bolts or main studs would use. Do this ONLY if there is enough clearance between the underside of the rocker arm and the generous radius on the rocker stud itself. From your pictures, I can't see any other clearance or interference issues. Don't forget the sealer on the threads.
Mr Gasket brand or Pioneer would do the job. But Jegs has the ARP's on sale right now for $0.90 each. https://www.jegs.com/i/ARP/070/200-8...CABEgKwrvD_BwE

Cheaper ones: https://www.ebay.com/p/79162389?iid=...CABEgIwSPD_BwE

https://www.ebay.com/itm/7-16-Cylind...-/202344701406

Edit: I just looked at your pics again. Your current studs are the cheap ones without the generous radius like the ARP's have. Buy the longer ARP's.

 

I appreciate everyone's help ! I'm going to get some longer studs and hopefully this will fix the problem. So far broke one of the studs in the head when removing it. Should be alot of fun removing it

 

I had a question about the movement, I noticed that the rocker arms had alot of play when it was on the base circle side to side. Maybe that could be the noise or is that normal ? Would guide plates help eliminate that play?

 

Yes. The guide plates will prevent the rockers from "twisting" on the stud. Not 100% but close.
Remember that with guide plates you have to lose the self guiding rocker.

 

Re-reading your post and am asking about the movement you're describing.
Does it allow the rockers to orientate themselves in the position of the picture below?



If so, then my reply above still stands. However there's more to it as well. From a tech paper I have by Jim Miller:

"As explained in text, this is the real example of what you don’t want to do. But it is very typical, and the problem is propagated more by the head companies luring engine builders into a false sense of “acceptability” to such an installation, by selling their heads with studs in them that have this stretched over placement, when they’ve had to move the pushrod for wider ports. The better alternative would be to leave the STUDS on the same centerline as the VALVES, and force stud rocker manufacturers to put their offset for the pushrod solely in the rocker arm, with an offset cup. This is what Ford did on their N-Head, and it is the best way. Otherwise, you need a stand (shaft)
system. Here’s the bottom line: You can never have an inline valve array cylinder head, like a SB Chevy, Ford, Mopar, etc., and NOT have the rotating axis of the rocker’s trunnion be IN LINE with the CAM. Any twist at all, is COMPOUND geometry, and will make it impossible for the roller to lay flat on the valve, or follow the correct straight down path on the Y-axis."

In other words, it's hard on parts. But you have to work with what you've got and guide plates will help in this regard.

 

Yes that's how some of my rockers looked a little side ways and would have space to wiggle and make clatter noise. I appreciate the help and suggestions. Hopefully the longer studs fix the issue everything else seems normal and like I stated before I'm not sure why it's quiet at first then it starts clattering after some time running like if something's loosens. That part just confuses me.

 

Rockers are ALWAYS a little bit sideways. BY DESIGN. The purpose is, to make the valve spin. The rocker is SUPPOSED TO BE a little bit off of "straight", so that as it moves, it runs on one side of the valve stem, and so tries to rotate the valve.

Jim Miller's rant is VASTLY oversimplified. Like so many, he grabs onto ONE idea, which in and of itself is COMPLETELY right (I'm not in any way accusing him of being "wrong" in that matter), and by putting on his blinders (what they used to put on horses so they couldn't see to the sides but ONLY straight ahead) exaggerates it to the point of ignoring EVERYTHING else.

Look at the witness marks on your rockers. I see where THE SAME ROCKER has been hitting the retainer BOTH near the trunnion at full closed, AND out near the tip at full open.

Only way they can hit at the trunnion is if (a) the retainer is too big, which it isn't, or (b) the rocker is improperly designed, which I'd prefer not to go down that road until no others are available, or (c) the push rods are too short.

I'm guessing (c). When you used your Comp 7702, what "optimum" push rod length did you arrive at?

OTOH, the SAME rocker also has witness marks where it's been hitting the retainer at full open. Tells me it needs lash caps, different shaped retainers, ... something.

Really, LSx valve springs with Comp 787 retainers and whatever spring seats and shims and whatnot to bring your no-name chinesium heads around to where the springs are at the correct installed height, plus the proper length push rods, might solve your problems. Might take longer or shorter studs once you get those REAL PROBLEMS sorted out, but just buying new studs by itself, is a crap shoot without being able to see the table let alone the dice.

Aluminum rockers are in and of themselves part of the problem. To get the necessary strength and fatigue resistance https://en.wikipedia.org/wiki/Fatigue_(material) aluminum has to be MUCH thicker, and ultimately HEAVIER, than steel. I would NEVER IN A MILLION YEARS put aluminum rockers on a street motor, for that reason. Butt hay, you got em, the deed is done; let's see if we can dodge or at least mitigate the consequences of a fundamentally bad "all the fast cars have em" illogical decision.

 

Your opinion of Miller notwithstanding (and I know little about the man other than his excellent tutorial on valve train geometry and that some of his interest was in promoting his shaft mounted rocker arm system), if you have rocker arms as shown in the picture above, then you have problems. I fussed for many hours with adjustable guide plates in an effort to get things into some reasonable alignment. Whether that will pay any dividends I can't say now but the answer will (or hope to) be available this fall/winter when my lump goes on the autopsy table.

As to the OP, I had addressed the witness marks on the rockers as well however that seems to have been glossed over.
You raise an interesting point with the pushrod length, vis a vis, valve train geometry. What worked for the previous Comp rocker arms won't necessarily work with the new rockers. Certainly something worth revisiting.

And while many don't, I'm in total agreement regarding aluminium and it's unsuitability for an engine that's going to see millions of cycles.

 

Using the comps cam pushrod length checker I found that the optimal length was 7.205 therefore I ordered the comps cam 7808-16.

I recall you mentioning the witness marks in a earlier post, There were originally 4 rocker arms that had jumped the valve stems when I took it for a ride and it started knocking pretty loudly and I took the valve cover off and noticed that they were completely off the valve stem in the pictures below I pointed out where the witness marks where on the 4 rocker arms and I also attached another photo of how I found the rocker arms once I took the valve cover off as a demonstration to how it got damaged in thoose two spots. I also attached another photo of the rest of the roller rocks and they have no signs of damage on them.

Nothing but great information on this page maybe using some shorter pushrods would fix the problem. I truly appreciate opinion, one step closer to solving this headache.

Anyone have experience with these heads (blueprint h8002k) I thought they would've had some quality retainers, springs etc,

 

​​​​​​Let's say it's fair to say the contact came after the fact. You seem certain. If it didn't, then you would have someplace else to look as well.
​​​​​​Regarding Comps pushrod tool, did you revisit the required length after the rocker arm swap?
I ask this because, even with similar ratios, we've found that different lengths were required between brands (Comp Pro Magnum vs Crower Enduro). Different lengths were also required when changing ratios in the same brand.
FWIW, I much prefer the mid-lift method for working out the valvetrain geometry. With decent measuring skills, it's 100% accurate and repeatable. Witness marks will verify the measurement both in terms of width of the rocker tip sweep across the valve tip as well as the position relative to the edge of the valve. Narrow sweep is best. Position is secondary up to a point. Both is what you're after.
But it might be worth using the Comp tooling to double check that your original length is still workable. It was observed by Kingdom that it appeared to be too short a pushrod. There could be something to that. The result might be that what you think is tight with regards to pre-load, really isn't.

 

Thank you, I'm going to revisit the the pushrod length with the new rocker arms hopefully this will fix it I got the whole motor apart right now.

Thank you everyone for the help, I got the new longer arp studs aswell.