Pulled my oil pan as part of a partial rebuild of my R56 N14 2009 Cooper S. No metal shavings or metal particles other than this roller. Anybody have a clue where this came from? I expected to find (and did) plastic pieces of the timing chain tensioner/guide because it's messed up but not this...

 

At first, I was thinking it could be some sort of bushing. A hell of a lot of the hardware holes in the have similar bushings. I think that its a little too thick-walled for that. Maybe a guide pin?

 

Still not sure exactly. Cylinder Head still in the shop, maybe the Head guy will know....

 

The tapered ends make me believe it's a guide pin, but the hole looks pretty small.Some, but not all guide pins have holes, i.e., one for mounting the starter. And the wear pattern looks like it was a "roller" of some kind, and the hole is where the "axle" was. What's the largest diameter metric bolt that will fit?

Have you checked the RealOEM parts lists --- https://www.realoem.com/bmw/enUS/select ? Both cylinder head and engine block have parts similar to your unknown.

 

Looks kinda like the pin on the rocker arm roller, but that may not have the hole in the center.