broken rocker stud

I broke a rocker stud off. seems the machine shop I had sent my heads to "traded" the rockers that were on my heads for a different set that were laying around and I didn't notice. rocker arm binded due to .500" lift cam on the rocker stud, and snapped it right below the threads (no threads left on the stud). I asked a machine shop how much it would cost to replace it, and he said $150 for 1 stud. that seems way expensive. I asked him what he does, he said he'll rethread it, then pull it out. I figure I can do that. My dad's sending me a threader through the mail, so I can put the threads back on it, and I've got a bid on ebay for a K-D rocker stud puller/installer. I've got a set of screw-in chromemoly rocker studs lieing around that are not in use and are new in bag, and are right size, however, they're the type with a collar. Anyone know how to install these things if you don't have a mill or a drill press? or atleast, anyone ever done it? Thanks.

If they caused this to happen then they should pay for it. Switching out your parts without your permission is not legal.

He probably had long slot rockers and the machine shop installed a factory rocker. Without comparing the 2 against each other anyone can make that mistake.

As for doing a repair it depends on how bad the damage is. A high spring rate valve spring can easily pull a pressed in stud out of the head. That's why screw in studs are so popular.

If the stud boss isn't damaged you can easily buy a repair kit. You'll need to drill out and extract the old stud somehow. Once the old stud is out, the hole is then drilled and tapped out to 3/8 NC threads. A replacement repair stud looks just like a pressed in stud except it's threaded on the end that goes into the head. Once it's loctited into the head it won't come out.

The hardest part about doing this repair is making sure everything is square. If you drill and tape the hole crooked, the stud will sit crooked and cause problems with the rocker. A machine shop will drill out the hole on a drill press or milling machine.

Although it's not that hard to do the repair yourself, don't rush it and make sure everything is square.

It's still their mistake and they still should not charge him for thier mistake.

Hey, if your using a 500 lift cam, you should have screw in studs and guide plates on your heads. if you dont thoses rocker studs will continue to break off. I work in a Machine shop...and i've seen what other machine shops have done to motors. and i always end up fixing there ****ups


Tom