I have had 2 rocker studs break on my AFR heads. The rocker studs were included with the heads and I assume they are of high quality given the nature of the company. The first broke a few months back and the second broke tonight. Both snapped while the engine was warmed up and I was not even driving hard, cruising at about 1800-2000 rpm. Tonight it broke while I was coming home from work. What a bummer!!

 

I had the same thing happen. In my case the culprit was the damper inside the spring. It broke into several pieces and wedged into the spring causing a bind that would not allow the valve to go down. Be happy that only your stud broke and you didn't bend a pushrod or flatten a lobe.

And figure out why it is binding. Check the dampers if you have them in the springs. I'm sure there are other things that could have caused the binding condition but that is what caused mine.

I just removed the dampers. I have read a few things about resonant frequencies and even took a class in college that covered it for a short period. Bottom line is it hasn't caused me any ill effects not running them and in my experience trying to stop harmonic vibrations in pumps, generic fixes like dampers don't always work anyway.

 

It's also possible that there was a bad lot of studs. If there is a metallurgist in your family, you might want to have them take a look and lend an opinion about the failure mode.

 

I have inspected the springs and pushrods, all fine. I think that the studs are just bad.

 

You arent the first to have problems with the AFR studs. Throw them all in a trashcan and get good ones.

 

I just got an email from AFR and they said that they had a problem with the studs due to a change in supplier. They are sending me a new set. I will use them and hopefully not have any problems.

Thanks for the replies.

 

i had the same problem a while back, i replaced all the studs with ARP studs and the problem went away.

 

Good guess, eh? A little search of the recent archives would have foreshadowed that email reply.