https://www.youtube.com/watch?v=Oqs-08ATRyU

Done both, welded material on and rotated out. Oil and ViceGrips, mostly works.

Had good luck with reverse drill bits. Start as small as possible and keep upsizing. Usually the friction heat and constant reverse torque turn out the broken stud.

Yes, me too. But I'd never tried to weld a broken stud that was recessed in the head. BTW, a 4" pipe wrench works much better than vice grips as it continually tightens its grip with additional force. IOW, it won't slip like vice grips.

A 4" pipe wrench works very well.
Much like a pipe wrench a vise grip works far better when positioned perpendicular
to the stud and rotated with the upper jaw dragging the stud rather than
pushing......the principle that makes a pipe wrench work so well.
I've also had luck welding onto a surface broken stud.....~60% success

Sheesh, he already had the welder out…

Weld a nut, use a socket in both cases

No galling, can use extensions to avoid spark plugs etc…

If there is any of the stud sticking out, I use a oxyacetalene torch to weld a nut on the remainder of the stud. The heat from the torch helps to release the stud from the head.

For one that is broken off inside, I make a drill guide jig and use a left hand drill bit that is slightly smaller than the broken stud.

For a 914 exhaust stud, I use the cast end off an early heat exchanger as a drill guide.

Patience is the key.

would you mind posting the pic in the first post?
Im not seeing anything and I love seeing how others solve things.

rich

Rich, here is the link to that on YouTube. try this. https://www.youtube.com/watch?v=Oqs-08ATRyU

I weld through a washer. This protects the aluminum surface then weld a nut to the washer.

Weird apple crap

Shows up fine on my iPhone.
Does not show up at all on my older MacBook

Sometimes Apple needs to stop trying to sell more HW and try supporting what they already sold.

I weld through a washer. This protects the aluminum surface from spatter or gouging then weld a nut to the washer.

Aluminum has a larger coefficient of thermal expansion than steel. This makes it much harder to remove steel bolts from aluminum heads when cold, because the aluminum shrinks more in the cold and "clamps down" on the steel bolts.

But, if you first run the engine for a few minutes or use a propane torch to warm up the head, it will make removing the bolts much easier.