Longer push rods ?

[danny waters sr]

Originally Posted by Alan Roehrich

Danny, can you define "knocking the rocker off" please?

Felt the car start missing around 6-6500 .
Got back to trailer and removed valve cover and rocker had come off.(polly -lock still on stud) not broken either. checked push rod and it was ok .i took the polly lock loose with my fingers and hex lock had not moved so i screwed it back on til it jammed (or locked) then i checked valve ajustment and was on the money. No problem til i installed new lifters.i will check the inside height later this week.i thing the longer push rods with new lifters could be the cause.

[Alan Roehrich]

So what you're saying is that the rocker jumped off of the pushrod, without the poly lock backing off?

Are you running guide plates, or self aligning rockers? With self aligning rockers, you could have enough flex to allow the rocker to pivot sideways and jump off of the pushrod, you'd be lucky not to un-key a valve.

It sounds as though you have reached the point where you have problems with flex and stability.

Are the pushrods good chrome moly pushrods, with the thick tube wall? For example, 5/16" x 0.100" wall, or 3/8" x 0.125" wall?

[danny waters sr]

Originally Posted by Alan Roehrich

So what you're saying is that the rocker jumped off of the pushrod, without the poly lock backing off?

Are you running guide plates, or self aligning rockers? With self aligning rockers, you could have enough flex to allow the rocker to pivot sideways and jump off of the pushrod, you'd be lucky not to un-key a valve.

It sounds as though you have reached the point where you have problems with flex and stability.

Are the pushrods good chrome moly pushrods, with the thick tube wall? For example, 5/16" x 0.100" wall, or 3/8" x 0.125" wall?

Yes it jumped off

Yes i am running guide plates

Yes it has3/8 comp push rods and comp replacement rockers

Never did this happen with the old lifters and the longer pushrods

[Reed Granrt]

Danny
Are you sure that you did not collapse the lifter with spring pressure. I have seen hydraulic lifters do one of two things, either pump up at that RPM or collapse. Bad clearances or trash in the lifter can let it bleed off suddenly and collapse. And if it does collapse, the pushrod will slip out from under the rocker. Of course the lifter will build back up and you will never know what happened.
reed

[Jim B]

Originally Posted by danny waters sr

i took the polly lock loose with my fingers and hex lock had not moved so i screwed it back on til it jammed (or locked) then i checked valve ajustment and was on the money.

It sounds to me that the polylock did back off first. If the rocker had jumped without the polylock backing off the polylock would have still been tight on the rocker stud and you wouldn't have been able to back it off by hand...to me the locking screw not moving and being able to unscrew the polylock by hand points to this conclusion....