F-head exhaust stud question

So, bought a used F-head to try to get the old girl running. #4 exhaust stud hole is wallered out good, no threads left. I was going to tap and helicoil. I know that #1 &#4 studs go through the water jacket so will I have a sealing problem using the helicoil ???

 

How about making the hole bigger, tapping and using a larger bolt ?

 

I would look at either putting a little 'J-B' weld on the fixed side of the threads (between base metal and new heli-coil) or the 'uber-strong' permatex solutions like the hydraulic 'thread sealant' (made for both low and high-pressure applications) or the 'green' permatex.

I'd look at both permatex.com and the J-b weld site.

I couldn't find any information on the helicoil website.

You might also be able to fill the hole with JB-weld, then drill and tap for the helicoil, then use permatex to ensure the bond is complete...

I'd guess others have a bucket of other suggestions.

Good luck.

d

 

The #4 on my F-head is broken off flush with the gasket surface. I'm looking forward to the certain joy that's going to present to me when I rebuild the engine..... I sense intense heat and Kroil in my future.....

 

I thought about that but I thought I would run into problems with fitting the larger bolt through the exhaust manifold.

 

I will look into that. I like the jb weld plus helicoil idea

 

the same two holes on my f head in the 3b were helicoiled at the machine shop. they both seep tiny amounts of antifreeze. if I ever have to take it apart, I will look for some kind of "fix" also.