"smjmitchell" wrote in message [...] 5.
Galvanic corrosion .. magnesium is at -1.6 V and alumnium at -0.75 V on
the galvanic table. That is a big different. You definitely need something
to separate the two or the magnesium is going to get gobbled up !!


Interesting comment but the rear case on many A-65 Continentals, and on most
C-85's, is magnesium bolted to an aluminum alloy crankcase. The bolts, of
course, are cad-plated steel and there's a fat gasket between the cases.
Whenever I rebuild one of these engines I always use magnedyne to passivate
the magnesium and alodine for the aluminum case. Magnesium doesn't need
any contact with another metal to corrode like crazy, but it sure does make
a nice lightweight accessory case, including good bearing pockets for the
oil pump and its shafts. So you magnedyne it and paint it, and of course
paint the crankcase too after passivating it, just like the Continental
overhaul manual advises.

Aileron hinges on the later Taylorcrafts are magnesium, and so are the
yokes, and so are the wheels. Beautiful castings but they must be treated
and preserved with great care.