Been thinking about this bell-housing/motor-mount thing and it
It occurred to me that what we need is a magnesium casting. Yes I know
magnesium burns but not thick parts so easily. VW crankcases
used to be made out of it and there has been lots of VW engine
fires without burning the crank case to my knowledge. I am sure Bill
will correct me if I am wrong on this. In WW II BMW radial aircraft
engines were made with magnesium crank case castings. Mag sand castings 
are not expensive.

The reason we need magnesium is it is tough to find a foundry that
can consistently sand cast thin walls 3/16 inch thick necessary to keep the weight
of this device down. Sure a die casting is light weight but we cannot afford
the tooling cost. With mag we could go to 1/4 inch wall and still be
under the weight  of a sand cast aluminum bell housing.

There used to be a lot of magnesium foundries in LA until the 
environmentalist put them out of business.

I'll look into it and see what I can find.

BTW I weighed Tracy's redrive plate alone without the spacers and bolts
and it came out at 7 pounds. With my motor mounts it is about 10-11 pounds.
Course anything you fabricate for comparable motor mount brackets
bolted to the engine will also weigh a couple of pounds apiece.

I can also cut the weight of the redrive/motor-mount  plate if we pop 
for hydra cutting by designing in some well placed large holes
in low stress areas. See the sketch below.

BTW the rear mount looks like it will come in under two pounds total
1/2 inch tube tripod, rubber bushing, bolts  and engine bracket included.

That makes all the steel motor mount parts not including the redrive/
motor-mount plate less than eight pounds total.
 
Paul Lamar
 
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