----------I once had a case welded across the oil cooler web.  The guy 
almost burned up his shop before he realized it was magnesium.  Then he did 
a nice bead, but it cracked again after a rebuild.  I believe a case that 
has cracked should be junked, there is a reason it cracked.  I think that 
over-tightening the head studs is what whipped that engine case.  I'll 
never try it again.

Can't do it on an older case say's I.  Aluminum?  Duh, don't know.

Eug,