Anybody run into this before?
Not me Adam. I wonder if it is of any consequence?
Allan from down under.
Use a thinner gasket!! Adam, I've never seen that before either. Just for fun, why not try another 4th main, and see if it does the same thing.
I don't recognise the rounded shape of the end of the shaft? Looks like it's freshly machined, maybe shortened compared to other driving plate shafts?
Do you have another to measure and compare?
Other option would be if the engine has been altered in some ways, like with a Model A crank shaft and a moved pan where the measures wasn't quite right - but if the hogshead holds the bands right over the drums, then that won't be the problem.
My vote would be on a shortened shaft. If the u-joint is pinned to the drive shaft and if the front shaft on the u-joint goes far enough into the drive plate shaft so it won't break in use, then I think it'll work. The fourth main's babbitt will wear faster than if the whole bearing surface was used - and it might start leaking oil faster, but with the low miles put on most T's every year, it shouldn't be much of a problem?
I suspect that Roger is right. Someone may have machined the shaft to install an accessory 4th main at some point.
Could just be a shadow but looks like a lot of clearance between the shaft and 4th main.
What does the rear main cap setting look like.
If the crank is set to far forward, it will look like that.
Machining the end of the tail shaft makes no sense, as all ball caps, weather stock, or ball bearing have to be the same in length, on the u-joint side from the flange to where the babbitt, or bearing starts, or something is not going to fit, clearance wise.
If it was at all possible to set the crank that far forward, which it is not unless the block has been modified, the engine assembler would have picked up a problem way before fitting the ball cap. The timing gears would be well out of mesh and the crank gear would be by that measurement to far forward to fit the cover.
I'm with the concept that the drive plate has been shortened.