[Bearman90]

Thanks for the input. I considered A), but the crank was ground down slightly and hence all journals measured in at slightly below stock spec of 50.00mm. If anything, I'd say that would mean clearance was slightly larger. In the previous setup, with stock crank that required no grinding, the same rods put no considerable wear on bearings that ran for 80.000 mi. At B), I ran 5W50 Mobil 1 FS X2, slightly thicker than the first 80.000 mi (0W40) deliberately for reduced wear at cost of slightly worse mileage due to my heavy clutch. I assumed thicker oils had better film strength, but will re-check. C) possible, however again no issues there the 80.000 miles prior so I wouldn't say that's a problem inherent to this engine. D) is possible, I will admit I did not measure inner bore in the rods with just the bearings installed, since they only come in this one size or oversizes anyway. I will measure bearing thickness compared to the OEM Volvo ones.

While I agree any or all of the above might explain the wear on a single bearing, I'm still very puzzled as to why identical patterns were found across multiple journals. Improbable as may be, my thoughts keep falling back to the grinding stone of the machine shop having been out-of-shape causing all the journals to exhibit the same hourglass shape. Especially since the main bearings (all of them) also show wear on the shell edges only.

If all journals were machined to exactly the same deformation, that would explain why the bearings have identical wear patterns, right?

Edit: Your post made me think, and I'm inclined to further investigate A. I've ordered a more precise digital bore gauge and micrometer, and will measure clearance post-mortem.