On Jun 3, 3:36 am, Stealth Pilot
wrote:

I've been dithering for weeks whether I'd bolt the halves back
together, tape up all the port faces and lightly bead blast the outer
faces of the block.
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I've had mixed results using beads -- glass and phenolic -- on
magnesium, in that specs of corrosion would appear after six months or
so. With walnut shells, I've had engines come back through the shop
after many years with the original paint intact.

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The paint I'm going to use is tempo aircraft engine enamel in the
rattle cans.
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Probably over-kill.

See if you can find a junked VW crankcase -- real junk; totally
unusable. Clean small areas using different methods; paint with
different paints. Keep good notes. Throw it out back of the shop
where the weather can get at it. Check it every now & then, and
update your notes. (Ditto for steel, WOOD(!), fibergals, aluminum and
so forth.) I think you'll be surprised at how well some of the
traditional methods/finishes hold up.

-R.S.Hoover