Found these parts in the sump, help me identify where they came off

[Pete.J]

Hi guys, as per the title, I found the parts pictured below in the sump of a N55 engine.

Background on the car:

This is F20 M135i with the N55 engine and PWG turbo, the car is used for racing competitively, we have a race coming up, and we found some metal shavings in the oil filter when doing an oil change.

So we popped the sump off, and found the below pictured parts.

The metal rings are alloy, and black piece is plastic.

Would be great if we could identify what part of the engine they came off.

Thanks in advance!

Peter

 

[JimboFresh206]

Chain guide?