I pulled the drivers side valve cover Saturday to adjust a 'clicking' valve. Turns out that the rocker arm stud on the number 5 cylinder exhaust valve had snapped. When I bought my heads, I had the spring load tested and they were dead on w/ the CAM manufacturers specs (Comp Cam XE274). What does this sound like? Possibly the spring is binding at high revs? I've only had the RPM's on this engine up to about 4K so far - engine has about 600 miles on it.

Any ideas what might have caused the stud to break?

Shane

Have you checked the geometry of the valvtrain ?
Did it snap or pull out ?

If you're using poly locks then likely it broke right below the adjuster, caused by excessive tightening. Bind is another possibility.

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Go to an ARP stud as there are some cheap ones out there that I have seen break.

What Rust said- if it snapped off just below the poly-lock it's likely an over-tightening issue (I do that semi-regularly for some reason- I like my locks tight). OR.... it could be the pushrods are too long and you're only grabbing a couple of threads at the very top of the stud with the poly-lock, which can also cause problems.

Binding will also break stuff, but usually pushrods will bend first. OR.... again pushrods can be too long and cause the rocker (stamped steel type) to run out of travel and "dig" into the stud at max lift, but that leaves some tell-tale marks on the rocker, too.

Did you find your problem yet, Shane???

No Rick, I haven't figured out what happened yet, but I did replace the stud w/ an extra one that I had. I'm hoping it was just a fluke otherwise I'll have to have my machine shop buddy check out the heads soon.

Is your email still the same Rick? The one in your profile?