Try bolt extractor.. not expensive and worked great in my experience.
Good luck

Map gas torch and double nut.

I got the original stud out with double nut, still need to work on its inner neighbor that was damaged but not initially stripped.

I have a MAPP torch now, and can try with locking pliers tonight. Or stop and pick up a more specialized extractor.
There isn't enough good thread exposed on the second to enable double-nut because of the alignment sleeve.


http://forums.pelicanparts.com/uploa...1761142127.jpg

A local hardware store will have a bolt extractor for sure.

I used something like this, no problem with a little heat: https://www.amazon.com/DEWILL-Broken-Extractor-Removal-Hexagonal/dp/B07Y1RG8C5

I would heat that stud and cool it several times prior to attempting to take it out. Last thing you want is to break the stud flush leaving the rest in the hole!
Also, putting a nut on the stud and mig welding the nut to the stud often helps. The mig current seems to heat the stud inside the case threads.

I picked up a torch and MAPP yesterday morning, but like a dummy, I didn't verify the torch fit the cylinder. It turns out the torch has a mini tank built-in you have to fill from the cylinder using a hose, which I didn't have.

But with the tip from Smadsen I got the collar off and then had no trouble getting the stud out with double nut.

Thanks everyone, the adventure continues! I'll leave this stud-strip thread off here, action continues on the rebuild thread.

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1179839-1979-sc-chewed-valve-total-rebuild-14.html#post12551913

You don't need a torch to get that stud out.