I think this is a great idea George. Much much better than my original
concept. If you don't mind doing the pattern over. Better cosmetically
as well.

I added an idea.
Instead of using that great big 15 mm 180 mm diameter thick plate
in the center use a stiffening cylinder just a little larger than
Tracy's PSRU. The cylinder should be about 40 mm high.

Only a 15 mm thick  50 mm diameter slug of metal in the center
where the input shaft seal is located is all that is needed.

Also taper the ribs as suggested by somebody just a while ago.

And for good measure and the last little bit of weight saving
cast in the pie shaped holes between all the ribs. Not shown
in this illustration.

Good idea and good work George.

Paul Lamar

Paul,
I need a fairly flat and wide surface to bolt down the bellhousing for
machining purposes.
The ribs as they are now have been machined flat to give that surface.
The original s were deeper at the bottom of the housing originally.
Not having that flat surface to work from causes vibrations which play havoc
on the machining process.

The center cylinder can and will serve that purpose. I use a similar
trick to machine the water pumps. use a 12 or 15 mm bolt through the
center hole to hold the whole works down. Also a few holes out in the
wings would not hurt.

Also you can cast in three or four towers out near the edges to be cut off 
after the engine side of the bell housing is machined. I don't think
these are really necessary but would add support.

Paul Lamar

We have to keep those machining costs down to make the price reasonable.
Having to shim the face which will vary slightly from housing top housing
EATS too much time. The flat back face is less difficult to hold down and
in fact I have to 'build-in' hold down tabs (on the MM plate) to allow for
the uninterrupted milling process. These will be milled-off when the face of
the MM is finished-off.

So for production reasons I will keep the ribs as they are, as I need them.

I will however take your suggestion of indenting the internal pad on the
inside.

I will be very, very careful with the thicknesses in this pattern as I am
becoming more aware of the effect of a little extra here and there.

I'm glad your pleased with the changes, I was concerned you might not like
them - I feel it's a logical step in the right direction and I agree
aesthetically it's better also!

I will start ASAP.

George (down under)

Be careful on that wall thickness.

Paul Lamar
 
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