Strange discovery on Mc 7 restoration

[steveohara]

Terry,

On this Mc 7 block the bore in the alloy block on the PTO side is one continuous size from the inside of the block to the outer edge of the seal boss. What you described would make sense but it occures to me that this discovery has ramifications that go beyond the seal alignment. I'm thinking of the guys that use gear boxes like the Dyna Drive and similar setups... since the boxes index off the outside diameter of the seal boss these engines with the bore in the bronze bushing way off center will have some poor gear fit problems depending on which way the bore is offset. On my Mc 7 the position of the crank is around .015" off center of the OD of the seal boss in the direction toward the carb. That would pull the main drive gear that mounts on the crank way out of proper mesh with the intermediate gear in the Dyna Drive box. If it were offset the other way it my not even be possible to assemble depending on how close the tolerances are in the old gear boxes.
Steve O'Hara

[Terry Bentley]

I dug out some nos bushings. Guess what? The ID is 0.035" undersized. That might just confirm whats been discussed so far.

[steveohara]

Certainly does. Thanks for the info.
Steve O'Hara