Hoping someone can help me out on this one....I have a 94 Camro 350 LT1 with aluminum edelbrock heads. I recently broke a screw in stud and broke the bottom out of the rocker arm. I replaced the stud and installed roller rockers. While the engine was idling and I was adjusting the new rockers the same stud broke off again. What would cause this? Thanks for your help. Dave

 

How much of a maximum lift are the heads rated at? If you're going beyond that, due to the lift of the cam and/or different ratio rockers, you could be binding the valve springs.
To avoid confusion, your duplicate thread is being deleted.

 

I am not sure on the heads.. they are Edelbrock performace LT1 aluminum heads. The car doesnt have a large cam in it... about 475 lift... i am using 1.5 rockers and drove the car for a year prior to the first one breaking.... i am thinking maybe an overextended/bad valve spring or a screwed up lifter?..is this logical ?

 

its like the pushrod is pushing the rocker too far....

 

I tend to agree with Chuck's thinking. Coil bind can do a lot of damage. Spin the engine by hand until the valve is fully open, then stick a 0.060 feeler gage between the spring coils and if the gage binds, you have a problem. You may want to check this link:
Valve Spring Tech - Lunati Power

 

OK, I will check this.... since this is pretty new, could this bind be caused by an over revved engine thus straining and ruining the spring(s)? can i have spring bind in the inner spring or only the outer? Thanks a lot for yur help and advice!

 

Yes, only one spring could be binding and cause the problem. Over revving can result in valve float, which is also very hard on valve gear, especially the cam lobes and springs. If you are using hydraulic lifter, there is the rare possibility that something in the lifter is causing the lifter internals to bind, and then then lifter acts as a solid lifter. If you preload a solid lifter as you would a hydraulic one, the valve is going to be held partially open, and when the lobe comes around it will cause the valve to open too far and bind the springs.

 

Pete, If there is something wrong with the lifter, i guess there is no way to check or validate this and the only way to repair if it is the lifter is to tear down and replace, correct? Secondly, if the spring does not have clearance as mentioned above .060, does this mean the spring is simply bad and I need to repalce or could it be indicative of something else wrong? Sorry to be so niave, but i am not so experienced and this is throwing me for a loop.

 

could only be a few things. bent/sticking valve, failing/binding spring, failing lifter. performer edelbrock heads springs are .600 max lift.

 

A bent valve stem will definetly cause the valve to jam and stress out things. It would also seem that if there is enough force to break the stud, then the push rod would most likely be bent. You really need to check all the pieces & make sure they are woring properly.