Official S65 Rod Bearing Condition Example Thread

[Assimilator1]

Technical discussions in this thread are nothing new, and are relevant.

Originally Posted by PaulGros

I have the complete data analysis from the OEM bearings that was rerun 02.02.2024 when I asked if the OE drawing could be checked. The following was rechecked:

Contact pressure
Bearing Hoop stress
Housing Hoop stress
Clearances

No anomalies were seen when compared to the original data. Unfortunately I can't share this data.

It's interesting that your list also contains OEM WPC treated bearings. My understanding of the process is it has a negligible impact on material dimensions, yet they are showing no wear even though clearance in theory is unchanged?

So just to confirm, the simulation was re-run with the original OEM bearings and the program confirmed the spec'd 0.046mm clearance is ok?

Re WPC bearings, I was wondering about that too.
Correct me if I'm wrong (memory's rusty here), but aren't WPC treated bearings ones which have had some sort of physical surface treatment (which minisculey increases the clearance, to no significant affect AFAIK) and also has some sort of coating over the bearing?

[PaulGros]

Originally Posted by Assimilator1

Technical discussions in this thread are nothing new, and are relevant.


So just to confirm, the simulation was re-run with the original OEM bearings and the program confirmed the spec'd 0.046mm clearance is ok?

Re WPC bearings, I was wondering about that too.
Correct me if I'm wrong (memory's rusty here), but aren't WPC treated bearings ones which have had some sort of physical surface treatment (which minisculey increases the clearance, to no significant affect AFAIK) and also has some sort of coating over the bearing?

Sorry I missed this post.

Yes, the data from the OEM parts was rerun with the latest software version with no issues found.

As far as I know, WPC is a form of micro bead blasting with no coating applied

[Assimilator1]

Originally Posted by PaulGros

Sorry I missed this post.

Yes, the data from the OEM parts was rerun with the latest software version with no issues found.

As far as I know, WPC is a form of micro bead blasting with no coating applied

Re WPC, yes that's it, I remember now you mention it!

Re OEM parts, are you allowed to tell us what clearance the simulation said it should be?

[Assimilator1]

And this is what rod bearings should look like even after 130k miles! Jump to 2:50s to go directly to the bearing shots (bloody link goes to the beginning, even though 170s is in the link!!).
Thanks to Matt@Evolve for publishing this btw.

PS The fact that it's not a high revving engine is irrelevant (IIRC it's redline is ~7k).

[Helmsman]

Originally Posted by Assimilator1

And this is what rod bearings should look like even after 130k miles! Jump to 2:50s to go directly to the bearing shots (bloody link goes to the beginning, even though 170s is in the link!!).
PS The fact that it's not a high revving engine is irrelevant (IIRC it's redline is ~7k).

I didn't look all though, maybe they said, but anyone who knows what clearance the S55 go with?

[CSBM5]

Originally Posted by Assimilator1

And this is what rod bearings should look like even after 130k miles!
PS The fact that it's not a high revving engine is irrelevant (IIRC it's redline is ~7k).

S55 stock redline is 7600 rpms...at least one day in time would have been considered pretty high revving!

[Assimilator1]

Originally Posted by CSBM5

S55 stock redline is 7600 rpms...at least one day in time would have been considered pretty high revving!

Ah ok, that is a bit higher than I thought, and yes that is still pretty high I'd say . As I recall, the later M3/4s have a lower redline, perhaps that's where I got 7k from.

[rajchalus]

2008 e93 m3 : 50,070 miles
Done at MRF🤩

[Assimilator1]

Originally Posted by rajchalus

2008 e93 m3 : 50,070 miles
Done at MRF🤩

Pics of the old bearings?

[Sammy82]

Here are my previously changed oem rod bearings:
44k km (~27k mls)
Summarized 3 days of trackuse
2 trackdays with BMW M, some laps on public driving (Hockenheim GP, Nürburgring GP, Nordschleife)
Oil was changed 5000-6000 km (3100-3800 mls)


The first rod bearings were replaced ~69k km (43k mls).

[LMBE92]

2010 E92 M3
Original bearings afaik
Replaced with BE Bearings & ARP Bolts by EAS in Anaheim
140,750 miles at the time of replacement

[M3SQRD]

Originally Posted by Assimilator1

Ah ok, that is a bit higher than I thought, and yes that is still pretty high I'd say . As I recall, the later M3/4s have a lower redline, perhaps that's where I got 7k from.

Redline has not changed on the s55 with 425 hp, 444 hp, 454 hp or 493 hp variants.

[Assimilator1]

Originally Posted by Sammy82

Here are my previously changed oem rod bearings:
44k km (~27k mls)
Summarized 3 days of trackuse
2 trackdays with BMW M, some laps on public driving (Hockenheim GP, Nürburgring GP, Nordschleife)
Oil was changed 5000-6000 km (3100-3800 mls)


The first rod bearings were replaced ~69k km (43k mls).

I don't understand you, don't you mean the 2nd rod bearings?

Originally Posted by LMBE92

2010 E92 M3
Original bearings afaik
Replaced with BE Bearings & ARP Bolts by EAS in Anaheim
140,750 miles at the time of replacement

Considering the mileage, and being the earlier type, they're not too terrible!

[januza]

So I just bought a 2009 E93 M3... Primairly city driven by an older lady.. 53.000km.. Should I start by changing the rod bearings now or should I wait.. Cost isnt a big issue.. thanks guys

[Helmsman]

Originally Posted by januza

So I just bought a 2009 E93 M3... Primairly city driven by an older lady.. 53.000km.. Should I start by changing the rod bearings now or should I wait.. Cost isnt a big issue.. thanks guys

Always tricky to know. Could hold up for another 200k km or blow tomorrow. But at 53k km I personally would wait (although replaced at 60k km myself, which turned out to be early). Ps. 2009 I believe use the earlier 088/089 shells which proven to wear more.

[M3SQRD]

Originally Posted by januza

So I just bought a 2009 E93 M3... Primairly city driven by an older lady.. 53.000km.. Should I start by changing the rod bearings now or should I wait.. Cost isnt a big issue.. thanks guys

I’ve changed mine at 25k miles for my ‘09 and 20k miles on my ‘12. With engines failing with < 10k miles, I wanted the oem bearings replaced asap. Went with BE V1 RB with BE ARP 2000 bolts.

[Helmsman]

Originally Posted by januza

So I just bought a 2009 E93 M3... Primairly city driven by an older lady.. 53.000km.. Should I start by changing the rod bearings now or should I wait.. Cost isnt a big issue.. thanks guys

Ps. Sorry for being obvious but while planning possible RB replacement I'd change the oil, cut up the filter and carefully check its absolutely clean from any shavings. And of course...always carefull warm up of engine/oil before stomping....
Most S65s have proven to live along life treated correctly. Key reason to replace the shells really is when buying used and without real knowledge how its has been driven and maintained. Quite a few are stated to have been driven by old ladies...