N62 Extreme Cylinder Wall Damage - Causes?

[Clavurion]

You've already seen Sreten's project Chicago episodes?

[BimmerBreaker]

Seems my earlier suspicions of this being a result of the piston dragging against the cylinder wall was correct



And my thoughts that it likely happened due to overheating is also probably correct. All cylinders showed some signs of this occurring



I think what happened is the engine overheated and all of the piston skirts started dragging against the cylinder walls. On most it wasn't bad enough to damage the cylinder wall dramatically, but cylinder 7 - maybe because it was the hottest, or maybe for... who knows why - started gouging into the cylinder. This certainly made some sort of scary noise, at which point I presume the previous owner shut it off. Then they removed the engine and sold it to me, lol


It is annoying that this happened. I rebuilt pretty much the whole engine (sans taking the heads off) and it had no leaks and ran great... it just smoked a lot. It really is quite odd how well it ran given the condition inside here. I think the N62 is a fairly durable engine, even if not always reliable...

But there is a silver lining because I had always planned on putting a 4.8 in there but at some point along the line I convinced myself I was ok with the 4.4 ...now that this happened, 4.8 was the only option. An extra ~30hp and ~50 N-m of torque

I will also be working on installing upgraded M62 headers or S65 headers. Once they got here I started to seriously doubt the S65 headers could be made to fit due to chassis clearance, but the M62 ones ... maybe. I'll be using the 4.4 to mock up header fitment and see how it fits in the engine bay

I think M62 headers could be good to get the N62 to ~370-375 and 510-520n-m which is spitting distance to an S62. The stock headers are awful

Originally Posted by X5chemist

Will a 4.8 N62B48(?) work? There's one in Austin for $1000. Seller says working perfectly. It's listed on MP, user Alex Mzhinskii. It has a video and pics. It's on pallet ready to go! Listed from an E70 X5.

I already have a 4.8 here



If the price was right I'd consider buying a spare but I think shipping would make it cost prohibitive...

But yes 4.8 fitment is the same as 4.4, and can be run on stock 4.4 engine management. Fuel injectors even seem to be the same per realoem

Originally Posted by Clavurion

You've already seen Sreten's project Chicago episodes?

No I have not

[Clavurion]

Project Chicago. It's about the Alpina supercharged version of N62 but very interesting to see all episodes. Actually this is the other of the only two Youtube channels I follow.

https://www.youtube.com/watch?v=SVM3xeCWuY8&t=1056s