Lude Generation

While working on his ATR engine (a7), Jan found some unwanted aliens in the sump. They appear to be made of aluminium alloy.
Any ideas?

hmmm, not an expert but after searching google images for 'found in oil pan', it looks like the remains of a bolt / bolt head. That's the only thing that looks similar.

It could have fallen down from the top end (cam carrier or similar) or from underneath in the block (oil squirters? oil pump pickup etc).

Could have been left in there from previous work?

Seems to be common on bimmer forums (to find bolts in the sump lol).

Looks like the left philange...... Or if nothing has failed...

yet...... it been left in there.
Bar opening up and checking, it's definitely the left philange.

If its aluminium, I can't think what it is. There's not really any ally nuts in the engine.

Looks like a rivet you find on jeans.

https://images.app.goo.gl/qYpv2sbwqBfQHvfL7

not as mangled as your example but enough of a similarity i think.

We think the culprit might be an aftermarket oil filler cap shedding its bits:

i agree, it doesn't look OEM

Hard to tell, if you can get hold of an identical one perhaps you can check what should be there? It would be unusual for a 'billet' oil cap to be 2 piece bolted or rivetted together, unless it was an ebay cheapy.

I had a good look through ebay but nothing shows the inside, every angle but the underside!