I need to remove a lot of steel bolts from an aluminum engine block, they feel like "welded" in there because the level of rust. Just turning them would crack the part, or break the bolts. I wonder what's the best/fast way to remove them, with minimum parts damage. I know:
- Use a propane torch to heat the bolt
- Cut the bolt at almost surface level then
- Do a cone drill and a cone bolt tip, arc weld the bolt
- Do a passing-through drill almost the bolt diameter to make it weak, then pass another threader, and then the one the bolt was
- Use salted water electrolysis to dissolve steel
Then finish unscrew it by any means :)
- Propane torch, very few tries, but see they need a lot of heat
- Arc welding a bolt on top: a few times, but difficult to control for small bolts
- Drill to make it weak and thread: needs a lot of work, basically re thread with new bigger sizes on each try...first M10, then M8, then M6.
Electrolysis...I'll put this aside as it is "special" and unorthodox for this, I believe. Once upon a time :) I "had" a long-term hobby making art blades, swords, knives and used it for engraving. Now the hobby time is going to the the darn car :) Anyway, it eats steel "fast", but need prep work. Salted water electrolysis won't eat aluminum.
Any other ideas? I need to extract about 15 old rusted bolts like those: