Re: Dumb question about the main bearings
When the rear cap is set for the the rear main, the center main should have about the same amount of clearance on each side of the center main, gap that is.
End play is not under .003, and not over .004.
You never know where the cap will come out for how much babbitt you will have on either end of the cap, especially if the crank is not from that block.
You could have most of the babbitt off either end, or anywhere in the middle.
But you have to have the center main right, and to have the cam and crank gear come out right, as the crank expands forward it has to have the gears that align.
We have built many Model T's with babbitt thrust on the blocks, as thrust does last longer, as you are doubling the thrust area.
Picture 1. is showing the rear cap with two thickness of babbitt on the front and rear of the cap.
Picture 2. is showing how the crank has to be centered in the block.
Picture 3. is showing how the fronts gap should look for forward crank expansion.
Picture 4. shows where the front of the gear should come out when the crank is set.
The last thing, all the measuring to center the crank has to start from the center main, it can't be done from any other point, not the rear, or front.
All the other places are not consistent.
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