Rod bearings on a tuned f10 m5

[ajm]

I had the rod bearings replaced on my tuned F10 M5 at 92,xxx kms as and by way of preventative maintenance. These are the used bearings. What do you guys think? Car has been very well maintained - 5w40 oil (Motul / Ravenol) changed every 4,000 to 5,000 kms

 

[TurboLlew]

I've asked the owner for permission to post the ones off my old car after 180000km (high 170k rounded up).
BootMod3, 730-odd whp so you have a reference point.

Not sure if this is useful.

This car had 7500km oil changes basically the time I owned it (IIRC 40K)

Mains



Didn't look too different.




The carbon build up was also not bad.



He is replacing rods (FCP) and bearings (ACL). Doing some other stuff as well apparently like nitriding the crank and more bearing clearance. Not replacing pistons but refreshing rings too. The valve guides and exhaust valves were the worst offenders in terms of wear. Oil delivery system looked good.

There was some pitting after cleaning so he will be doing new valves. Guides are not available from BMW so using Supertech IIRC.

 

[ajm]

Thanks Llew. Given the mileage on your previously owned M5, the wear-rate looks remarkably good. I have had several oil analyses done on mine and they indicate a high percentage of fuel dilution in the oil, but without any unusual metal wear. This seems not to be a mechanical issue. I have had new injectors and high-pressure fuel pumps fitted. A leak down test revealed no issues and the car uses no oil at all between oil changes and emits no smoke at all from the exhaust. I have concluded that the fuel dilution is tune-related and, as an added precaution, I am now using Motul Competition 300 V 5W 40. That aside, the car is a beast and runs perfectly. I also have several tunes to play with - ranging from mild to aggressive - so that keeps me excited.