[Rsnellie]

Ok I’ve got two thoughts.

First and what I see as most likely of my two opinions is that the ring gear isn’t seated all the way. I suspect the person who built it removed it and didn’t reinstall by heating it up and allowing it to rest all the way down on the pressure plate. My original pressure plates needed heat to remove the ring gear. The ring gear gets removed so that you can use it to lock the flywheel in place to tighten the flywheel bolts. They only require like 16-17lbs of torque so it won’t draw the ring gear flush. This would account for the ring gear rubbing the back of the gearbox. It’s hard to tell because the ring is recessed on the mating side so it will look like it’s fully seated when it is not. I fortunately caught this on my clutch job when reinstalling. We need an actual measurement just like you took to be sure, but at first glance it looks to me like the rivets are sitting to far down in the ring. Most photos I see including my own they are almost flush to the starter ring gear.

Second, seeing how this looks to maybe be an older pressure plate and flywheel… perhaps they were original to each other and balanced together. I know older tolerances often times weren’t as accurate on some parts. Is it possible the mounting locations for each bolt securing the pressure plate to the flywheel aren’t exactly the same.. so that if you clock it incorrectly it could be offset slightly and causing the interference only on half of a rotation? Can it be reclocked so that it turns true? Is that something worth checking? Just throwing out random thoughts for you and sorry if it’s a waist of time.

I’ve always been taught to put indexing marks when separating pieces like pressure plates and flywheel. I don’t see them here, but it could be a scribe line not obvious in the photos