im swaping some al. L98 vette heads on my car and after torqueing down all the rocker arms the rocker arm fill fall off if taped by hand. whats up with this?

 

lock nuts are bad, are these the nuts from the original heads(are they the same size).....when you say torqueing down, you dont mean it like that do you? You are just tightning down till the slack is out of the pushrod then an extra turn?

 

yeah im torqueing it down till the push rod no longer turns then doing 3/4 turn and they still just pop off. i am using the stock rocker arms and nuts off the old heads.

 

did you old heads have screw in studs?

your not trying to use 7/16's nuts on 3/8's studs are you?
Ive seen it tried before.

 

no the old heads had press in studs.

 

I can't say I have had the problem myself, but I'm pretty sure that the thread pitch or design on screw in studs is not compatible with the factory lock nuts and poly-locks of some sort will be needed. This exact thing happened to a friend of mine on the 355 he put in his S10... He was a bit confused as well at first but said he found some info on the problem and went poly-locks and didn't look back.

HTH

 

Are the push rod guide plates still on the head?

RBob.

 

Does the rocker come completely off, or does it just slide off the valve tip?

If it does the latter, you need either guide plates installed on the heads, or self-aligning (rail tip) rockers. That's what I think you're telling us.

If the studs are 3/8", then they are the same as Poly-Locks would be. There's no issue with "incompatibility"; the threads are all the same size.

 

Makes sense.... I guess the simplest explanation for this problem is crappy locknuts that don't hold.