Looks pretty clear to me it was an oiling issue....No way no how I would run the clearances that tight for sure. Not 100% familiar with windsor oiling but if you really think it wasnt a bearing clearance isseu(which is hard to believe)then I woudl start looking there as to where oil travels in the engine. Hard to tell from pics but looks like it had plenty of "stuff" going through it too, but could just be the pics and lighting.