Quote:
Originally Posted by 400A
Hi Terry, that's a real nice looking housing! Will it work with all stock OEM parts (Engine block, bell housing, etc) and does it look exactly like an original from the outside? Seems like a wonderful upgrade over the OEM housing.
Many thanks for all that you have done for the Model "A" hobby.
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The initial design of the flywheel housing (Part #A-6395) was revised 8 times during the 4 years of production. I believe the exterior was identical for the first 7 revisions, and each revision added more material to the inside hidden area in an attempt to make the housing stronger. The 8th revision on Oct 26, 1931, added external ribs at the bell housing bolt hole locations. This 8th revision was used on very late 1931 vehicles, was an over-the-counter part that was available at Ford parts counters. The 8th revision didn't solve the basic strength problem.
The basic problem is that the housing is too thin where the 4 attachment bolts are. All 8 revisions were 1/2-inch thick. The new housing is 7/8-inch thick and based on the 7th revision.
Flywheel housing loads come from the front axle wishbone. The wishbone is in compression during acceleration, braking, and when hitting a pothole or curb. This compression is transferred to the bellhousing and then the flywheel housing, causing it to crack at the 2 lower bolt holes.
The lower part of the housing, located below the two lower attachment bolts, is a cantilever beam.
The cantilever beam formula for strength is based on width x height cubed.
For simplicity, imagine a 1 x 4 piece of wood as a cantilever beam. If placed with the 4-inch side down, the strength is 4 x 1 x 1 x 1 = 4. If placed with the 1-inch side down, the strength is 1 x 4 x 4 x 4 = 64.
The new flywheel housing is 7/8-inch thick, and the thick area is 3 times wider at the lower attachment bolts than a stock housing. Doing the math, the original housing is 1 x 1/2 x 1/2 x 1/2 = 0.13, and the new housing is 3 x 7/8 x 7/8 x 7/8 = 2.01.
The new housing is 2.01/0.13 = 15.46 times stronger.
All of our parts have the appearance and interfaces as original Ford parts.
An O-ring is supplied to seal the rear camshaft, so a gasket and upper shims are not required unless you are building a "points" car for judging.