Replacing rusted exhaust cylinder head studs

[Pete.]

I have done several of these. If they are not too far gone then welding a nut on, waiting a minute for the heat to expand the ally and then winding the stud out works most times. When they are very rotten then all they do is shear off either flush or inside the hole with very little effort. When that happens I drill them out and helicoil.

 

[Hobowallet]

I have done several of these. If they are not too far gone then welding a nut on, waiting a minute for the heat to expand the ally and then winding the stud out works most times. When they are very rotten then all they do is shear off either flush or inside the hole with very little effort. When that happens I drill them out and helicoil.

Looking at them I would say one bolt on each cylinder is still full intact with just surface rust to the nut.

One bolt on each cylinder looks to have almost exploded open, and the last just has a small piece of the last fillings of metal that belonged to the nut.

Seemingly at this stage the exhaust is not leaking, and whilst I would generally let a sleeping dog lie I know at some point I need to address this.

I am looking to get an impact chisel to crack off the nuts and then clean up the remaining pieces of metal, all being well I should have enough exposed stud to work with.

I like the idea of using an arc welder to heat the stud but obviously this would be the secondary faze of getting a nut welded on to have some purchase for removal. Unfortunately I do not have a van nor trailer anymore and only have access to DIY grade welding equipment so everything would need to take place in my workshop or I need to strip parts to send out.

Drilling scares me to death after hearing horror stories of people drilling too deep and punching through the oil well.