Roller tip lifter curiosity

[trotterlg]

have roller tip rockers in my 3100 carbed Fiero engine. Had a very curious thing happen. Ran the engine for a while and it developed a miss. Pulled the plugs and #2 was dead. It got spark so pulled the valve cover. Exhaust rocker was backed off and the pushrod had fallen off the rocker arm. Thought, I just forgot to adjust it, the nut was near the top of the stud. Set the lash about one turn down and put it together, ran perfect for like 45 seconds, the clack clack and miss miss. Took the valve cover off and the rocker nut was backed out. Had a spare rocker arm (bought a set for a V-eight) so I put one of those on. Ran near two minutes and it backed out. Seems the little half ball the rocker socket rides on has little oiling cuts in it that cause it to rotate and un-screw the lock nut. These are not cheapo lock nuts either, good aircraft lock nuts, (Thankyou Boeing) but it still turned the nut out. Set it again and put a jam nut on top and life is good. Think I will just do this to all of them, I think as they wear in that things will be better, but just be aware that strange things can happen. If I had my choice I would use the pivots without the oiling cuts in them so they do not induce rotation in the ball. I did get to run it up a little today and it just pulls flat from 3,500 on up, only got to about 6,500 today, but it was pulling the same as it was at 5,000. Kind of fun. Larry

[geoffinbc]

That's not un common on re used studs and nuts. It is better to use the poly locks that COMP and Crane sell. They can be re adjusted countless times and wont back off once locked.

[3400-95-Modified]

What rocker combo are you using? are these the roller tip ones that are sold for the 3.1L engines? Last I remember these are not adjustable and you tighten it down till its locked down on the thread... the Lifter pre-load is determined by the push rod length.

[geoffinbc]

My guess would be the COMP Magnum roller tip rockers with conversion studs since he said he bought them for a V8. I hope the accompanying rocker ball was used and the OEM ones were not re used since they are not the same.

I agree if they stock net lash studs are being used then they wont work and are not designed for adjustability.

[Superdave]

I've had to use jamb nuts on the Magnum roller tips before. Same problem, they kept backing off.

[geoffinbc]

Strange. I used all the parts COMP sent with the rockers, set it once on my engine build and never touched it again.

[Superdave]

I had one of the pins slide out as well, lucky I heard the racket and pulled off the valve cover to check...

If that bearing would have come all the way out I bet the rocker would have popped out the spring locks.


I have them now in my Nova as well.