Broken Rocker Stud
 

Hey guys-

Here's the scenario... On a recent trip the car started running really rough on the highway. I wasn't beating on it or passing a car or anything, just cruising at around 2500 rpm. Luckily I was close to my friends house (5 minutes from his exit after driving 3.5 hours). I limped the car to his house and found out the next day that the #8 intake stud had broken and it was just kinda wedged between the broken piece of the stud and the valvecover.

The strange thing is that the EXACT SAME stud broke in the exact same manner about a year before on another long trip. Between the two, however, the entire motor had been rebuilt (it's a 383 now, was a 350 heads/cam before) and the only things that remained the same are the aluminum LT1 heads and the block. I'm not sure if the mechanic numbered everything coming off when he pulled the motor (I don't think he did), so I think the odds that the same rocker found its way onto the same stud would be pretty slim but I'm going to check with him on Tuesday.

The stud breaks right where the thread inside the nut begin. Another strange thing is that no matter how hard I tried (or the nice Napa guy who saved my butt the first time) to get the lock out of the center, we couldn't. We broke an allen wrench or two trying...

I've asked a lot of people and here are the possibilities:

- Rocker stud is slightly mis-aligned, causing strange forces on it
- Sheer coincidence
- Rocker is defective and either locks up and snaps it or hits the stud under load
- A head defect Chevy did a recall on (sound familiar? - This was a shot in the dark a friend of mine said)

Any ideas are greatly appreciated. I'm getting my emergency stud replacement kit together for any long trip...

Thanks in advance!

-Dan

Strictly guesses here...coil bind,poor geometry,misadjusted rocker.

What size studs?

They are 3/8" studs. I don't think it's a geometry problem but I will check the spring. I bought the heads with the springs on them, so I can't really vouch for the miles that I didn't put on them. I'm thinking of checking that spring... Maybe there's something wrong with that individual coil.

Cool! Thanks guys! :) I'll let you know what I find out.

-Dan