[Jimbobeast]

Basic info:
This is a stock 1970 RAIV. The engine was assembled 10+ years ago with stock parts and rotated every few months. I broke one pushrod, so I replaced them all and also installed polylock rocker nuts since I no longer trusted the old lock nuts to stay in place after being removed. All the valves were adjusted and she started up on the first 1/4 crank and ran smooth as silk. I took her to be aligned (about 2 miles) and on the way home a rocker came off the valve and pushrod (see photo) on cylinder #7.
the polylock was tight, there is no apparent damage to the pushrod, rocker or nut.
So either I did not adjust that valve correctly or perhaps there is something wrong with the spring? The engine has about 2 hours of run time on it total.
I'm going to reassemble and readjust that valve (the installed height of the spring seems correct and the same as the others), but should I be concerned about the other springs and should I just replace all the springs?
Were the RAIV springs special, and where can I get replacements?
Thanks.

[Butcher]

More thread showing on that polyloc
than the others.

[steve25]

First off if the stock RA4!rocker studs are not flat on top a poly lock will not hold adjustment right.

Next your issue may be as simple as just not using the poly locks right.
The proper way is to make the adjustment you want, then set the Allen down tight, then tighten up the outer nut a 1/8th to 1/4 turn more to fully lock everything together.

Also did you use the needed RA4 length push rods when you got those new ones?

I guess you’re only running .469” lift and not .519” due to those Comp Cams 1.5 rockers?

[Kenth]

Check lobe lift on #7 exhaust.

[steve25]

Sorry, forgot to post that when you make that last 1/8 to 1/4 turn of the outer poly body you need to hold the Allen set in place.

[Joe's Garage]

Originally Posted by Kenth

Check lobe lift on #7 exhaust.

^^^^THIS^^^^

That's a possible symptom of a lobe going away.........

And, with the obvious difference in threads showing on the locking screw of THAT polylock, the odds go way up.

Good luck!

[Jimbobeast]

Well, the correct answer is maybe yes to all.
The rockers are 1.65 and the correct length/diameter RAIV pushrods were used On that #7 cylinder exhaust, even with the allen screw out and the polylock bottomed out, there is still too much play. The pushrod is intact and clearly by feel seated in the lifter. The rocker stud is tight and identical to the others. The valve spring is the same height as the others and within spec. Therefore either the valve is stuck open or the cam lobe is "wiped". Neither scenario is good. I had hoped to have this car ready for Mecum in January, but that does not seem likely now. I'll check the compression in #7 tomorrow, but I'm betting a rebuild is coming. Damn. So close.

[blueghoast]

Might not of had the push rod seated in lifter correctly, I've done that before.

GT

[Joe's Garage]

Losing the lobe shouldn't affect valve seal.

So long as the valve is opening and closing, and the valve is sealing and the rings are good, there will probably still be pretty good compression.

If you're able to turn the poly-lock down to the end of the threads, and the rocker is still loose, you've either wiped the lobe or collapsed a lifter.

Either one will require the intake and valley pan to come off, so you might as well just pull them off now and know for certain.

Good luck!

[steve25]

Excuse my ignorance, but who makes roller tip only Pontiac rocker arms in a 1.65 ratio?

[AG]

Comp Cams

[Jimbobeast]

OK, valvetrain Gurus, here are some more pieces of the puzzle.
All the valve springs and valves are at the same height (with rockers removed). A straight edge lies flat along all of them. Ditto for the tops of the 7/16" screw in rocker studs. I re-torqued all just to be safe. Nothing moved. If my rudimentary knowledge of Pontiac valvetrain geometry is correct, this most likely means all the valves are seated, none are bent and hooray, I don't (probably) have to take off the heads.
All the rockers were adjusted on the base cam until the pushrods barely spun with my fingers, then 1/2 turn more. None of the allen locking screws had come loose on the polylocks.
When I removed the rest of the rockers and pushrods, I found 3 pushrods with the ball popped out and one with the ball pushed into the tube (see photo). WTF? To me this indicates something amiss on the lifter/cam side, and I'm betting bad lifters. IIRC, these were "Rhoades lifters" with variable lift (less at idle for smoother cam and more vacuum). Does this make sense? On exhaust #7, where the rocker came off, I can depress the lifter plunger with the pushrod with minimal effort. All the rest no depression. So best scenario, the lifters are bad but the cam is intact and the valves are OK which means only pulling the intake and replacing lifters and pushrods and no removal of heads or (god forbid) cam (which means engine out).
Does any of this make sense in an automotive engineering manner of thinking?
Mecum Jan 2025 is now out of the question but I can wait for 2026. Bummer.

[steve25]

At this point I for sure want to know how much seat pressure you have?

How much open pressure you have at .520” lift ?

What brand push rods those were, or from where they came from?
Is the internal C clip still in #7 lifter?

[Jimbobeast]

Originally Posted by steve25

At this point I for sure want to know how much seat pressure you have?

How much open pressure you have at .520” lift ?

What brand push rods those were, or from where they came from?
Is the internal C clip still in #7 lifter?

Yeah, seat pressure, open pressure - I got no idea how to check. The heads were assembled around 2010 by Yow's Machine shop, known locally for their expertise in Pontiac engines. They did 2 RAIII's, 2 RAIV's and a 455HO for me with zero issues. Sadly, Yow's machine shop no longer exists. The heads were fully machined with hardened valve seats, new valves, springs, the whole works.
I guess they could have screwed up somewhere. The crank, pistons, cam and the rest of the engine were assembled by yours truly. More likely I made some error along the way.
Or bad lifters. I like that better.

[Jimbobeast]

Are RAIV lifters anything special? What are the specs for RAIV springs and where can I obtain new ones if needed?

[johnta1]

Original lifters are different, less travel.
The pushrods are also longer than other pushrods.
They are also wider than other pushrods.

Those ball-ends being broke off suggest a binding or misalignment issue?
The rockers a Pontiac rocker or a Ford rocker used as a Pontiac?

Pushrods too short?

[Joe's Garage]

If the lifter on #7 exhaust depresses without resistance, it has FAILED and you're gonna have to replace it. You should probably replace all (16) lifters.

You might as well pull off the intake and valley cover so you can get a better view of what is going on in the lifter valley with your cam and lifters.

The multiple pushrod failures is troubling, especially the fact that the came apart. Hopefully no debris has 'migrated' into the bottom end.....


Here's what I would do:

Pull off the carb and intake and valley cover. It might take an hour or so. just get it out of your way now.

Inspect the lifters for this side - the ones you already took the pushrods out of. Do they ALL still have the retaining rings in them? Do any of them besides the one that failed look weird? Tilted cups inside or ???

Then inspect the lifters, pushrods and rockers for the OTHER side. Again looking for anything that appears 'odd'.

Carefully remove the rockers and pushrods from the passenger's side. Watch out for more disintegrated pushrods. Be careful to keep any pieces - like those balls that you found on the other side - from falling into the oil pan.

CAREFULLY remove the lifter on #7 exhaust and inspect the bottom end. Is it still nice and polished looking or concave?

Inspect that lobe on the camshaft. Is it polished or scuffed and worn? I'm hoping that you get lucky and can salvage the camshaft.

Continue with the other lifters, carefully inspecting each lobe on the camshaft. You might need to rotate the engine to see the top of each lobe and verify that it's not wearing abnormally. That will be easier with the spark plugs removed.

With the multiple pushrods coming apart and at least the one lifter failing, I'd suspect that you will find more problems as you disassemble the valvetrain and camshaft/lifter stuff.

Let us know what you find.

Good luck!

[steve25]

True RA4 factory lifters are limited travel.
Only .050" adjustment range where as any other hydro lifter has 100" to maybe .120" adjustment range.

[Jimbobeast]

I should be able to disassemble the intake/valley cover today and see what's what. I'm thinking the springs are too tight, causing multiple lifter/pushrod failure. If the cam is OK, I will call Butler and follow their recommendation for new valve springs, pushrods and lifters and put them in. My neighbor is a drag racer and he might have a valve spring pressure tester just to see what they are pulling.

[Formulajones]

Just a heads up, those style rockers with the cheap ball type pushrods don't mix.

Those rockers specifically need a hardened pushrod, and that used to be stated in the paperwork, don't think that has changed as the rockers are still the same. They will chew up the soft cheap pushrods in a hurry, don't ask how I found that out. Really has nothing to do with spring pressure, I chewed up those ball style pushrods with those comp rockers decades ago on a SBC using stock Z28 springs for a flat tappet.
Switched to a good one piece hardened push rod and all was good until I then found out the fulcrum on the rocker turns black and blue because the ball rides on the sides rather than fitting properly down into the pocket. So the rockers came off and went in the trash.