Untill you confirm bent valves no reason to give up on the motor. Even then not a reason.

I've helpee bring an m62tu back from the dead where timing chain broke while running and took out 8 valves. (Annoyingly not same head).

The marks on the cylinder can just be carbon and close calls.

If you look at a new piston you'll see thru have dents for the valves to get very very close.

Get a compression test and start there

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)