that will look kind of funny. best not to scratch, grind, or otherwise mar up the case surface. looks unprofessional.

It is not really a "Hot" tank, it is a 55 gallon drum full of carb cleaner. We let the mag cases soak 4 to 6 hours, and the alum cases 6 to 8 hours. We then clean them off with solvent(Safety-Kleen) and then blow dry them off. We then scotch brite all the mating surfaces. Here in the aerospace area of Southern CA. there are ultrasonic places that will ultrasonic a M-1A tank.

Got it Otto! The hot tank I'm thinking of is a caustic soda tank, heated.
Alloy doesn't last too long in there!
Ultrasonic cleaning an M-1A!!! I love it!!
Don't you just love America, everything is big in the States!!!

Your original question was regarding the removal of paint that some unknowing previous owner had placed on the case. Unless you get some chemicals that will definitely remove the paint, then you'll have to do significant work when it comes back. Most carb cleaner I know of does not remove paint (some brands damage paint, but they don't remove it).

Before going the blasting route, I would try using some spread-on paint stripper on the external areas of the case. I'm not sure whether it would be best to use it before, or after you cleaned the case in any tank though...

-Wayne

Oh, and in case anyone doesn't know this already - painting the heads and case is like placing a thermal blanket on your engine - it prevents proper heat transfer, and will cause your engine to run hotter than it should...

-Wayne

I will retell a story told to me by George at Ollies ( the best Porsche engine machining guru and Porsche machine shop in the country). I had once asked him to bead blast a case for me, he said NO WAY, not even a little bit of the case. It seems that they once tried to clean a customers case for one of those outlandlishly expensive engines. They took all precautions to the extreem in terms of plugging up holes and openings to prevent beads from getting inside. They cleaned and cleaned and very carfully inspected the case for residual beads. the engine was assembled and only ran for a few minutes before it became aparent there were big problems. Somehow some beads were missed and completely RUINED EVERY single part in a VERY VERY expensive engine. They have a picture of it on the wall. Consequently they will not ever bead blast a case again.

As for my own experience I have recently repaired a Porsche engine that had been bead blasted by someone, it almost ruined every part in the engine. The crank had to be reground, all the new bearings replaced. What a mess it was.

Some of the secret hiding places for the beads are:
1. behind the plugs in the crank shaft. Unless the plugs are completely removed you CANNOT get all the beads out.
2. Behind all the oil galley plugs in the case. All the galley plugs MUST be replaced.
3. The oil tubes in the heads, and again behind the plugs.

There are probably more but I forget, off hand.