F-134 exhaust manifold stud

I was adjusting the exhaust valves today on my f-head and pulled the manifold off to make it easier. When doing this the far left (when you're looking at it) stud came out with the nut attached to it (guess it was rust-welded together). I figured I'd just screw the stud back in when reinstalling the manifold, no big deal.

Well, when I went to screw the stud back in it, it went in until it was snug. After looking at it I realized I'd be better off just replacing the stud and nut with a bolt, so I backed it back out and when I took it out coolant shot out of the whole and high speed!

The only thing I can figure is that I somehow managed to push the stud through into the water jacket in the block. These studs don't normally go into the water jacket on an F-head do they?

I ended up sending the stud back in covered in Permatex gasket maker. It seems to be holding alright, but i'm afraid if I go at highway speeds for a long period of time, the pressure might eventually work its way through the permatex. I was thinking about maybe using plumbers tape and permatex.

anyone have any ideas? or has this happened to anyone before?

thanks,
evan

 

I don't know about the F-head but a lot of motors have bolts and studs that go into water jackets, putting permatex or thread sealer on them is normal.

 

So glad for this post to know coolant gushing out of manifold bolt holes is expected on the fhead when pulling the manifold

 

Studs are the way to go on the exhaust. If that was a bolt it would have rust welded into the block and broke.

 

Yes, as Jw60 says use studs, and coat the threads going into the block with sealer, I prefer Permatex. The sealer does two things, it seals the threads of the stud preventing leaks, and prevents serious rust issues. I coat the outside threads with anti-seize compound and use brass nuts to make future removal easier.

 

Yeah, it ain't no fun, especially breaking that rear stud. Stainless studs sounds like a good idea, where did you get them?

 

Thanks all for the suggestions, I was super lucky and with a bit of penetrating oil was able to get the rusty bolts out without breaking the heads off. That's when the coolant gushed

 

Your actually lucky. Most of those that enter the coolant passage break off and seems like tool steel when you try to drill them. I have one like this on an original military D block with the serial number intact.

 

Mine had enough crud to where It didn't leak any fluid when I pulled the manifold the first time. That is.... until I poked around in the hole and the floodgates opened unexpectedly