[oliverguy]

I would try it, what do you have to loose if it's a big ball of rust now. I'm using electrolysis a lot now, but never did anything like an engine. A carb casting cleans up nice. Nothing seems brittle to me afterwards.After the part is done I soak it in vingar for a little while to loosen the carbon (I use a carbon cutting electrode). The speed is based on the size of your electrodes, the concentraion of your solution and the amount of amps you put to it. It's fun to do. For something big I'd suggest doing it outside.

I strain off the garbage and reuse the water, just adding more occationally.