Official S65 Rod Bearing Condition Example Thread

[DrFerry]

Originally Posted by OatsMalone

49k, 08:

They look about as expected for the mileage and year. Sleep better now that you have them done. What type of bearings and bolts did you replace them with?

[OatsMalone]

Originally Posted by DrFerry

They look about as expected for the mileage and year. Sleep better now that you have them done. What type of bearings and bolts did you replace them with?

That was my impression, not scary wear but as expected and happy to have it done. Shop used VAC kit for the replacement.

[0-60Motorsports]

Originally Posted by Helmsman

Thanks a lot for the pictures. Looks fairly good in the pics, whats your judgement looking close up?

Ps. Looked at Mahle's S65 bearings at all as an alternative?

Can you link me to the MAHLE ones?

[Helmsman]

Originally Posted by 0-60Motorsports

Can you link me to the MAHLE ones?

https://marmotorsport.com/bmw-s65b40...peekQ8K1OVQWYC

There is a quite extensive discussion with a Mahle rep on this board as well as on the UK m3cutters (Mahle is UK) which I found quite interesting.

[0-60Motorsports]

Originally Posted by Helmsman

https://marmotorsport.com/bmw-s65b40-m3-e90-e92-e93-mahle-motorsport-conrod-bearings/?srsltid=AfmBOoqpKhHfM1643e3uTd9XXSG8qAVkkenYFengl opeekQ8K1OVQWYC

There is a quite extensive discussion with a Mahle rep on this board as well as on the UK m3cutters (Mahle is UK) which I found quite interesting.

Thank you

[DW_CT9A]

Originally Posted by Helmsman

There is a quite extensive discussion with a Mahle rep on this board as well as on the UK m3cutters (Mahle is UK) which I found quite interesting.

Indeed. Good stuff. In case anyone is interested:

https://www.m3post.com/forums/showthread.php?t=2086170

[Helmsman]

Originally Posted by 0-60Motorsports

Thank you

Here's a couple on the subject.

https://forums.m3cutters.co.uk/threa...arance.266859/

https://forums.m3cutters.co.uk/threa...arings.267487/

[Assimilator1]

Originally Posted by Helmsman

Got it, thanks. Although BE made measurements and claimed the ARP 2000 provided better roundness (can't find this info any longer, seems they have taken it down?), the ARP 625 is certainly being used for the S65 by various shops. It is also promoted for the S65 rod bolts by ARP, which surely must be worth something. I personally wouldn't hesitate to have them reused but will be interesting to hear about your final decision and finding.
Ps. I guess you will be able to see on shells wear if the roundness is totally out of whack.

And again, really looking forward to some high resolution pictures on the shells!

Thanks

Looks like the S65 bearing wiki has been taken down .

Originally Posted by pitkin_g

Unknown mileage. My car has 125K and i purchased it at 120K.

Damn, that's a shame, so no receipts correspond to the ACL shells & ARP 625s?
Any idea when the previous owner bought it? (year/mileage).

[pitkin_g]

Originally Posted by Assimilator1

Damn, that's a shame, so no receipts correspond to the ACL shells & ARP 625s?
Any idea when the previous owner bought it? (year/mileage).

Nope, no data

[TassieBMW]

Here's mine which I just changed. 170,000km, 09 E90 DCT, original 088/089 bearings. Looked like the car had BMW service intervals for most of its life with a few exceptions.

[Assimilator1]

Originally Posted by TassieBMW

Here's mine which I just changed. 170,000km, 09 E90 DCT, original 088/089 bearings. Looked like the car had BMW service intervals for most of its life with a few exceptions.

Ooff, they were in a bad state! But pretty much what we expect for those type bearings and with that mileage.

[TassieBMW]

Originally Posted by Assimilator1

Oof, they were in a bad state! But pretty much what we expect for those type bearings and with that mileage.

My worry is if they looked that bad, how are the main bearings....

My original plan was to do both at once; drop the bed plate with engine in car and roll in the upper mains as one specialist shop here in Australia does.
I ended up deciding not to as I couldn't understand how to properly seal the bedplate and block back together without access to the front and rear main seals to apply the BMW primer stuff and seal off the sealant channels.

[Assimilator1]

Hmm, Deansbimmer, whose workshop rebuilds S65s has said (paraphrasing), it is very dubious to do the mains in situ. IIRC the issue is, how do you carefully guide the crank in when it's over your head?

As for the mains, yea I think many of us wonder that too, but it is rare for mains to fail.
So far, from our (non-exhaustive) blown engines list, 34 engines have been confirmed with mains failure and 6 suspected. (Their maybe a few to add from the m3cutters list from the UK).

[jvictormp]

Originally Posted by TassieBMW

My worry is if they looked that bad, how are the main bearings....

My original plan was to do both at once; drop the bed plate with engine in car and roll in the upper mains as one specialist shop here in Australia does.
I ended up deciding not to as I couldn't understand how to properly seal the bedplate and block back together without access to the front and rear main seals to apply the BMW primer stuff and seal off the sealant channels.

IIRC, the BMW sealant syringe is not produced anymore, so mechs need to apply the sealant the old way. I'm not sure of that, I just think I saw somewhere.

Originally Posted by Assimilator1

Hmm, Deansbimmer, whose workshop rebuilds S65s has said (paraphrasing), it is very dubious to do the mains in situ. IIRC the issue is, how do you carefully guide the crank in when it's over your head?

As for the mains, yea I think many of us wonder that too, but it is rare for mains to fail.
So far, from our (non-exhaustive) blown engines list, 34 engines have been confirmed with mains failure and 6 suspected. (Their maybe a few to add from the m3cutters list from the UK).

You know what some say about the main bearings problem being due to quick engine stops, I mean, under a minute or so?

Like a start-stop system, or turning engine off to wait your line on drive-through to move on.

They say, the chain tensioner plays a substancial amount of force on the crank, which is pretty fine to support if main bearings have oil pressure enough.

But when you turn engine off, pressure goes 0, but chain tensioner has a check-valve that doesn't allow the tensioner pressure itself to go 0 too, so it keeps the force on for several seconds (or some minutes), because luckily the check-valve is not a perfect seal.

That would explain the numbers on main #1 failure, cause people wouldn't do that "misbehaviour" on purpose, but they would.

[Assimilator1]

Originally Posted by jvictormp

IIRC, the BMW sealant syringe is not produced anymore, so mechs need to apply the sealant the old way. I'm not sure of that, I just think I saw somewhere.




You know what some say about the main bearings problem being due to quick engine stops, I mean, under a minute or so?

Like a start-stop system, or turning engine off to wait your line on drive-through to move on.

They say, the chain tensioner plays a substantial amount of force on the crank, which is pretty fine to support if main bearings have oil pressure enough.

But when you turn engine off, pressure goes 0, but chain tensioner has a check-valve that doesn't allow the tensioner pressure itself to go 0 too, so it keeps the force on for several seconds (or some minutes), because luckily the check-valve is not a perfect seal.

That would explain the numbers on main #1 failure, cause people wouldn't do that "misbehaviour" on purpose, but they would.

Are you sure about the tensioner having a check valve? Not come across that with other engine's, there's just a spring putting pressure on the tensioner's piston to maintain chain tension when the engine's off.
I don't see any check valves for the tensioners in the S65 engine pdf either (see attached), but I do for the chain lubrication and VANOS units.

Btw, it's not about the speed of the engine stops (that can't be altered), it's about the frequency of engine stops, anytime time you start any engine their is briefly contact between bearings and crank until oil pressure builds up. So more starts = more wear.

[jvictormp]

Originally Posted by Assimilator1

... more starts = more wear.

That's normal for every car, but S65 has a different scenario that adds to that.

I don't know if the link will work, so I'll paste the text below it:

https://www.facebook.com/share/p/1BfV542PQ2/

Gareth Howell
22nd october 2024

Main bearing S65 issues.
Please understand this is an opinion / observation regarding a problem we have been studying in recent months. After six lci engines suffering main bearing failure on main bearing 1.
Again, you are all entitled to your own opinions but please don’t shoot me down for trying to explain our recent findings and our humble opinion on what may be causing a problem on LCI stop start engined cars.
We no longer take customers vehicles in for engine rebuilds so please understand, this is not a scare mongering exercise to generate work, we don’t need any more but more a piece of hopefully useful information to help those who may be affected and potentially extending the life of their engines.
We now only build engines to order and provide engine Dyno sessions for S65 and S85 engines and build ecu’s and our own race cars.
We have spent several weeks trying to understand why no1 main on LCI engined cars are failing. We have built rigs and measuring equipment and have concluded the following.
When I say OK below, I’m saying relatively normal.
S85 mains ….ok
S65 pre lci e9x mains ….ok
S65 palmer sport deactivated stop start cars mains…..ok
S65 lci stop start active, mains….. looking problematic.
Observation / conclusion 1.
Unaffected engines above, when they start cold, there is a delay before engine oil pressure is achieved. However there is no oil pressure anywhere and there is no load from tensioners pulling the crank into the relatively dry front main bearing. Hence why you may hear chain rattle on start up.
When the engine is stopped, in most instances we believe the engine will more often than not, be left for a few minutes before restarting. Ie an amount of time exceeding the time the tensioner holds onto chain tension.
Observation /conclusion 2
The hydraulic cylinder for chain tension has an internal one way valve. (We have cut apart to verify). This is not particularly efficient, however, it does provide tension for about two minutes.
THIS IS WHERE THE PROBLEM MAY LIE.
On a stop start car, we believe the tension on the chain remains in existence, the oil pump drops its oil due to its type and upon start up there is a delay of oil pressure to the bearings which is measurable and there is a pre existing load from the chain tensioner system which is also measurable on a rig we have made. This is where we believe the problem lies, with load being applied to the main bearing by the tensioning system with no lubrication until the oil pump provides its delayed feed to main bearings. This potentially explains the main bearing failure we are seeing which is predominantly seen on main bearing 1. The bearing most loaded by the chain tensioner.
Studying all the engine types that use this exact bearing, bearing clearance, chain tensioner system, we can only deduce that the main bearing failure is far more likely to occur on the stop start cars.
Therefore
Cold start after a long period
Zero chain pulling crank upwards
The potential problem.
On stop start, the crank will be getting pulled upwards before oil pressure is achieved. Ie. Car pulls up, engine stops, tension is retained before bleed off, no oil pressure at bearings, car restarts within 2 mins, load on front main from tensioner until oil pressure is reached.
In conclusion.
On an average journey, stop start could occur 10 times, that is 10 main bearing, tensioner pre-loaded starts.
Compared with zero main bearing pre-loaded tensioner starts on non stop start engines.
One selfish reason I have posted this report is, unlike the big end bearing problem caused by a different problem on non stop start cars, this particular problem usually destroys the main bearing surfaces of the engine block, this means the rebuild will require an engine block, we are all going to struggle in the future if engine blocks are not recycled.

[Helmsman]

Originally Posted by jvictormp

That's normal for every car, but S65 has a different scenario that adds to that.

I don't know if the link will work, so I'll paste the text below it:

https://www.facebook.com/share/p/1BfV542PQ2/

Interesting!

Ps. Coded out the stop/start function first thing when I got the car. To avoid repeat start/prior being warm, but seems it may have provided additional upside.

[Assimilator1]

Originally Posted by jvictormp

That's normal for every car, but S65 has a different scenario that adds to that.

I don't know if the link will work, so I'll paste the text below it:

https://www.facebook.com/share/p/1BfV542PQ2/

Interesting, I will have to ask them about the 1 way valve in the tensioner, seems to contradict the pdfs on the face of it.

[Assimilator1]

I don't believe this case has been posted here, if it has, LMK!

I stumbled across it in the E9X M3V8 UK FB group.
208k miles! MY 2013. Strangely, despite it's year, it appears to have the earlier lead-copper bearings, so unsurprisingly the bottom bearings are all showing a lot of wear!

Photo shown here - https://www.facebook.com/photo?fbid=...06918150019459
LMK if you can't see it.

Video here -

[boxeeh]

Recently had the RBs done on my 2013 E92 M3 w/ 40,723 miles. Went with BE Bearings + BE ARP bolts.

[e36mikee]

49k miles 2010. Rate my bearings :

[rdoctor]

Not the worst I've seen but pretty damn worn. Good call getting them swapped out. It would be helpful to know the oil change info leading up to this service. Type/weight/frequency.