Re: Advice on removing snapped s/s bolts from alu block
Mark, fastest cheapest best result might be to just find a good machine shop, let them deal with it. If the machinist has any doubts, find a better shop.
PBlaster is great stuff, it chemically attacks the corrosion. So does Kroil--but you have to mail order that.
Torches are nice but can weaken the metal. A CO2 extinguisher or small tank of CO2 from a gas shop can do the same thing by freeze-soaking the parts. Slotting the bolt with a Dremel and using an impact hammer is also good, I'd try the PBlaster and freeze cycling it 3-4 times before whacking away at it, in that sequence. And if none of that worked, THEN center punch it and carefully drill out as much as you can. In the worst case, you overdrill and use Heli-Coils. But a good machine shop can put that engine in a drill press and chew the studs out, or they can weld a crossbar onto them and then just spin them out.
I'm going to guess they'll get rid of the bolts for under $50, as opposed to screwing around all afternoon worrying about it. Hardest part of the job would be finding a good machine shop.