Check these bad boys out! (Rod Bearings)

[FOURSIXTEEN]

Originally Posted by Helmsman

And the work shop who did the job couldn't simply done it wrong, too much torque etc? Not suggesting anything, just curious.

Cheers

Done by BMW, or so I was lead to believe.

[Sneaky Pete]

Originally Posted by kawasaki00

Maybe you need to search again, quite a few people changed over to a thinner oil years ago on that site. Leonardo629 was one of the first

Yes they have..nevertheless, the OEM spec oil viscosity is to cover heavy duty usage at high ambient temps. If you are not in that group then you may well risk a lower viscosity oil.
That this is now the third engine (at least) that has suffered problems while using 0W40 weight oil, should caution anyone considering that oil weight if they are a hard user in a hot climate.

[Sneaky Pete]

Originally Posted by pbonsalb

Why is the ethanol problem limited to E9xM3s? If your theory is correct, every brand and every motor in every brand should be experiencing ethanol related bearing failures. But we don't read much about this. And E9xM3 are not the only high rpm motors around. And some other cars are tracked just as much.

It would be nice to find a simple explanation, but I am not sure there is one.

I have no idea whether fuel dilution of the oil is a problem with the S65....but It would be interesting to know if varying levels of ethanol in fuel has any effect on the ion sensing anti knock system. Google isn't being very helpful on this.

[jcolley]

Originally Posted by Sneaky Pete

Yes they have..nevertheless, the OEM spec oil viscosity is to cover heavy duty usage at high ambient temps. If you are not in that group then you may well risk a lower viscosity oil.
That this is now the third engine (at least) that has suffered problems while using 0W40 weight oil, should caution anyone considering that oil weight if they are a hard user in a hot climate.

Curiously, it's also the the third engine with very tight oil clearance, maybe that's something we should look into. Seems like correlation to me.

[Sneaky Pete]

Originally Posted by jcolley

Curiously, it's also the the third engine with very tight oil clearance, maybe that's something we should look into. Seems like correlation to me.

Thats probably it then...the OP should definitely stick with the Motul 0W40 seeing as it worked out so well for him the last time!

[jcolley]

Originally Posted by Sneaky Pete

Thats probably it then...the OP should definitely stick with the Motul 0W40 seeing as it worked out so well for him the last time!

Not sure I implied that. I don't think thinner oil helps. Personally I like the idea of fixing the problem, that's just me.

[BMRLVR]

Originally Posted by Sneaky Pete

Yes they have..nevertheless, the OEM spec oil viscosity is to cover heavy duty usage at high ambient temps. If you are not in that group then you may well risk a lower viscosity oil.
That this is now the third engine (at least) that has suffered problems while using 0W40 weight oil, should caution anyone considering that oil weight if they are a hard user in a hot climate.

No one said oil would fix the issue with the S65, it was just suggested that a 0W40 was a better fit for the type of usage and clearances ran in the S65. Besides, a 40 grade is hardly a thin oil. Many, I'd even venture to say "most" performance cars out there run a 40 grade engine oil or lighter with a few but very few speccing a 50 grade. In the automotive world a 60 is not a common engine oil at all, and it's spec by BMW as the only oil regardless of climate or usage is strange to me. But I'm gonna leave the oil talk alone at that since the horse is dead so I'm gonna stop beating it.

This engine had other problems that was not oil related..... But we've beaten the dead horse so many times on that one too. Heck if you look you may find lots of data around that issue on this forum with lots of commentary from many experienced engine builders that are among the best in the industry.

[pbonsalb]

http://www.sciencedirect.com/science...96890415010195

Originally Posted by Sneaky Pete

I have no idea whether fuel dilution of the oil is a problem with the S65....but It would be interesting to know if varying levels of ethanol in fuel has any effect on the ion sensing anti knock system. Google isn't being very helpful on this.

[Hujan]

I am very tempted to try Motul 300v 15w50 in my M3. It actually yields a slightly higher HTHS than Castrol TWS (5.3 vs. 5.1). The question is how the cold flow compares at startup. I still fear that much of the damage to the rod bearings we've seen is from startup wear. And, obviously, the high ester content and aggressive additive package can only help. Plus the cost is not much worse than Castrol TWS.

If Motul 300v made a 5w50 or 10w50, it would probably already be in my car.

[Sneaky Pete]

Originally Posted by BMRLVR

it's spec by BMW as the only oil regardless of climate or usage is strange to me.

Well logic suggests that it is used because it gives the best reliability overall.
As the issue is accelerated upper bearing wear occurring during the power stroke then maximising the oil film strength in that area with a high viscosity oil seems like a logical remedy....if so, using a lower viscosity oil appears to be contraindicated.

[IIAp3x]

nonetheless, good save on your bearings!

[Shredicus]

Originally Posted by Sneaky Pete

Well logic suggests that it is used because it gives the best reliability overall.
As the issue is accelerated upper bearing wear occurring during the power stroke then maximising the oil film strength in that area with a high viscosity oil seems like a logical remedy....if so, using a lower viscosity oil appears to be contraindicated.

As long as the oil can get to the bearings the hydrodynamic wedge should be preserved. I'd say flow and pressure are far more important that film strength in this context.

[BrewRifle]

What bearings and bolts did you replace the OEM sets with?

[Rich150001]

Can you share the Blackstone report?

[FOURSIXTEEN]

Originally Posted by Rich150001

Can you share the Blackstone report?

Yeah, let me dig around for them. I will post if I find them

[WhatsADSM]

If anything I would think this aligns well with the tolerance stack up theory as you see dramatically different wear patterns on each of the cylinders.

[Green-Eggs]

I've officially posted my offer to free Polaris oil analysis for the first ten people who are interested and think they qualify. This will help answer that question whether there's any ethanol dilution at all, before anybody wants to debate about what it means.

http://www.m3post.com/forums/showthread.php?t=1227869

[Green-Eggs]

Originally Posted by pbonsalb

http://www.sciencedirect.com/science...96890415010195

If I understand this correctly, the conclusion was that ethanol increases the signal-to-noise ratio of ION sensing for determining detonation and spark/burn quality. Increased SNR is a good thing. So that means the ethanol helps the ION sensing and doesn't hurt it.

[jcolley]

Originally Posted by Green-Eggs

If I understand this correctly, the conclusion was that ethanol increases the signal-to-noise ratio of ION sensing for determining detonation and spark/burn quality. Increased SNR is a good thing. So that means the ethanol helps the ION sensing and doesn't hurt it.

Increasing the signal would effectively raise the integral for a given combustion event effectively reducing the threshold to protective action by the "klopfregelung" function.

In layman's terms, it would be more likely to cause false knock sensing.

However, it would seem likely that BMW adjusted the associated calibration tables for the ion sensing in one of the many software versions since there is a US specific version of each of the major software revisions.

[BMRLVR]

Originally Posted by WhatsADSM

If anything I would think this aligns well with the tolerance stack up theory as you see dramatically different wear patterns on each of the cylinders.

I think this guy is on to something

[Green-Eggs]

Originally Posted by jcolley

In layman's terms, it would be more likely to cause false knock sensing.

Would that be true if it lowered the noise floor instead of amplified the signal? Not sure if that's what happened here as I didn't read too deep into the report.

[Sneaky Pete]

Originally Posted by jcolley

Increasing the signal would effectively raise the integral for a given combustion event effectively reducing the threshold to protective action by the "klopfregelung" function.
In layman's terms, it would be more likely to cause false knock sensing.

Is it not the case that if a (false knock) signal generated exceeds the upper threshold it is simply discarded as being out of range - rather than seen as a knock event and ignition timing pulled?
I suspect how the software handles out of range signals by adjusting the upper threshold is rather complex.
I also wouldn't be surprised if BMW has quietly dropped the ion sensing tech for the F8x M3/4 range (but I could be wrong).

Originally Posted by jcolley

However, it would seem likely that BMW adjusted the associated calibration tables for the ion sensing in one of the many software versions since there is a US specific version of each of the major software revisions.

If ion sensing calibration adjustments in software updates were made to improve reliability then that could conceivably account for the general fall in S65 engine fail rate over the last couple of years (a quick look suggests ~24 engine failures reported by M3post owners in 2014 against roughly 12 in 2015).
It certainly suggests that owners on older software might want to consider paying to get it updated.