Matt865 Posted August 18, 2023 Share Posted August 18, 2023 After discovering metallic flakes in the filter while doing an oil change on our 2012 520D F10 N47, I have decided to rebuild the engine. The sump was full of metal scraps, including the brass pieces shown above; to provide scale, I set a pen next to one of the pieces to illustrate its size; it seems to be a bushing; and, to date, I have removed the head, the crank, the pistons, and the connecting rods without locating it. The shards of metal are the result of the common issue of a faulty large end bearing. Leave a comment if you recognize these pieces, and I'll update this post if I'm able to track out their origin. Quote Link to comment Share on other sites More sharing options...
Paqngo Posted August 18, 2023 Share Posted August 18, 2023 Bushes for chain tensioners. He won't be gone for long, and will know it. Quote Link to comment Share on other sites More sharing options...
DreamWeaver Posted August 18, 2023 Share Posted August 18, 2023 I can't place it, and it's not completely bizarre, so I have no idea what to make of it. Perhaps it's related to the balancing shafts. Quote Link to comment Share on other sites More sharing options...
Paqngo Posted August 18, 2023 Share Posted August 18, 2023 Sure seems odd. You'd think it would make a racket if it was at the right place.If you follow me here... Quote Link to comment Share on other sites More sharing options...
Matt865 Posted August 18, 2023 Author Share Posted August 18, 2023 I made a thorough inspection when I took out the timing chains, and everything seemed OK. I haven't taken off the balancing shaft yet, but it spins easily. Quote Link to comment Share on other sites More sharing options...
Matt865 Posted August 18, 2023 Author Share Posted August 18, 2023 I knew going in that this 520's motor was shot, so I've never even heard it start. Quote Link to comment Share on other sites More sharing options...
Matt865 Posted August 18, 2023 Author Share Posted August 18, 2023 At first glance, I thought it may be the timing chain or tensioner, but with further inspection, I saw no cause for concern. Quote Link to comment Share on other sites More sharing options...
DreamWeaver Posted August 18, 2023 Share Posted August 18, 2023 Please share your findings with us if you do. Quote Link to comment Share on other sites More sharing options...
Motoman Posted August 18, 2023 Share Posted August 18, 2023 The central part resembles a valve collet. Quote Link to comment Share on other sites More sharing options...
Mistral Posted August 18, 2023 Share Posted August 18, 2023 Somewhat like a supercharged Bush. Quote Link to comment Share on other sites More sharing options...
DreamWeaver Posted August 18, 2023 Share Posted August 18, 2023 My initial thought was collet, but you undoubtedly already know that. Quote Link to comment Share on other sites More sharing options...
ByteStorm Posted August 18, 2023 Share Posted August 18, 2023 The holes are the incorrect size for a valve collet, but the center one does seem a little like a turbo bearing outer race (holes to allow oil in). Quote Link to comment Share on other sites More sharing options...
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