Rod Knock and Bearings, Crankshaft Damage?

I recently picked up my 2008 E92 M3 and after a few days of driving I parked and started to hear rod knock and when I got home I listen carefully and by my best guess cylinder 8's bearing is going. I have a scheduled appointment to do the bearings at a local shop on Monday and am going to tow the car down. I was wondering if there is any way to tell if I damaged the crankshaft or any signs in the car's behavior that would indicate I did? I guessing (and hoping) I didn't because when carefully driving home I didn't notice a significant drop off in power which probably means I didn't spin and bearing and hopefully didn't hurt the crankshaft. Any and all comments/help is appreciated thank you!

Only way to confirm whether the crankshaft is damaged is to look at the RBs and determine if any had spun. You might get lucky and find a single RB that’s about to spin and the crankshaft has not sustained any damage. Either way, if you’re hearing rod knock, then it’s time to pull the RBs and replace them with a set of BE, ACL, Mahle, or VAC RBs and BE/ARP rod bolts. I have BE V1 and BE/ARP 2000 rod bolts installed in both of my e92 M3s.

M3SQRD wrote

Only way to confirm whether the crankshaft is damaged is to look at the RBs and determine if any had spun. You might get lucky and find a single RB that’s about to spin and the crankshaft has not sustained any damage. Either way, if you’re hearing rod knock, then it’s time to pull the RBs and replace them with a set of BE, ACL, Mahle, or VAC RBs and BE/ARP rod bolts. I have BE V1 and BE/ARP 2000 rod bolts installed in both of my e92 M3s.

Yea I was pretty sure that's the case. I guess I'll see on Monday when it gets towed to the shop and they take out the RBs. I hoping I got lucky and its only cylinder 8 and it didn't spin... Thank you for the advice!

m3seb wrote

Yea I was pretty sure that's the case. I guess I'll see on Monday when it gets towed to the shop and they take out the RBs. I hoping I got lucky and its only cylinder 8 and it didn't spin... Thank you for the advice!

I wish you the best! There have been some really horrible looking RBs yet the s65 crankshaft remains undamaged.

M3SQRD wrote

I wish you the best! There have been some really horrible looking RBs yet the s65 crankshaft remains undamaged.

Thank you! The shop said they use VAC RBs and ARP bolts so I should be all set.

Hope for the best. If it is indeed “Rod Knock”, it’s not going to be good.