So I own this 2003 Cooper s and have recently been deprived of my driving ability. The car got an oil chain(royalpurple) a new timing chain tensioner, and since has started making an extremely audible knocking and squealing. I initially thought that one of the chain guides has broken so naturally I started my journey of disassembling my little engine. After dropping the oil pan I have discovered this mysterious piece of metal. I would be greatly honored if someone could help me identify it.

Please and thanks. Love Kirby

 

Going to move you to the Stock Problems/Issues area. First thought was part of the oil pump but below is a link to a recent thread on the matter and do not really see a shape similar to what you have in your picture. I put a different cam in so know what under the valve cover looks like but don't remember anything like that there either.

https://www.northamericanmotoring.co...ain-cover.html

 

Looks like the side of one of the main bearings, unfortunately.

Nik

 

Check out the below, does look like a main engine bearing piece.

http://www.autohausaz.com/images/MI-11217829946.jpg

 

I was going say it looks like part of this:

https://www.ecstuning.com/b-genuine-...l/11217829949/

Thats really the only thing that has that half moon shape:

https://www.ecstuning.com/Mini-2003-...e/Mechanical/2

I would be very concerned about that bottom end and would pull the pain off and see whats going on in there.