350 Chevy Rocker Arm Stud

[Badger2008]

Just put a rebuilt vintage late 70's SB chevy 350 block in my buddies boat. Mercruiser 250.
On the first run we got water in one cyl. Probably manifold problem. It bent the valve and the rocker arm stud. After replacing the valve He attempted to straiten the bolt and broke it off with about 1/2" still haning out. He says the book states these press in? Is this true or can it be turned out with a vise grip? If it is pressed how do you get it out? Or is this a machine shop job only?

Thanks Chuck

 

[Haut Medoc]

Re: 350 Chevy Rocker Arm Stud

Welcome to iboats......
I believe they are pressed in & there is a special tool for removal......
If there are threads left.....​

 

[SuperNova]

Re: 350 Chevy Rocker Arm Stud

Yeah, they're pressed in. The tool requires some thread on the stud to work, but this is a very fixable situation. Just get a 3/8-24 thread die and rethread the stud. Then use a few washers as spacers over the stud and thread a nut down onto the washers to pull the stud out. If you can get a slide hammer to grip whats left of the stud you could try that also. The new stud can be just pressed in with a swing press. Or you can tap the hole to 3/8-16 and get a screw in stud replacement from Napa. No-not the kind with a hex on it- the ones i am talking about are a straight stud with 3/8-16 theads on the bottom, then a small shoulder, then 3/8-24 threads on the top-which is the factory thread. You can PM me if you need more detail.
--
Stan

 

[Bt Doctur]

Re: 350 Chevy Rocker Arm Stud

Only way I`ve seen that damage is when a piston hits the valve, never from ingesting water.Sounds like valve float or cam timing issue

 

[Mkos1980]

Re: 350 Chevy Rocker Arm Stud

Be careful on how much force you apply pulling out. I know of a number of peeps who have accually cracked the stud boss off on one side. Sometimes the force of GM shooting them in so hard, they get so hot it accually welds itself in. If there are NO threads you can drill out the stud BUT, this takes alot of time and a ton of drill bits. I did it once for a friend and never again. I think I went though 10-12 titanium bits. Not cheap at 5 bucks a pop.