Official S65 Bearing Specification/Clearance Wiki

[SenorFunkyPants]

Originally Posted by jcolley

I'll just go back to reading and learning.

That would be a great shame...the topic needs as many clear, informed and articulate heads as possible. Especially one who can put his hands up to a comment written in frustration. I think the S85 issues have great relevance as they give context to those that the S65 may or may not have.

[catpat8000]

Originally Posted by regular guy

Recommended values of eccentricity:

For passenger cars: 0.0002 - 0.0008” For high performance cars: 0.0006 - 0.0012”

Dr. Dmitri Kopeliovich: Geometrical parameters of engine bearings[/COLOR][/I][/INDENT]
Conclusions:

Minimum eccentricity: 0.00090"
Maximum eccentricity: 0.00170"
Expected results: 0.00060" - 0.00012"
# Within recommendation: 6
# Outside recommendation: 10

As measured we can certainly see some bearing eccentricity. According to the article quoted above, the expected results should range between 0.00060" - 0.00120" for high performance cars.

I've been reading this article and have a question. It looks like the bearing eccentricity is well outside the range the article quotes for "passenger cars" and slightly higher than the range quoted for "high performance" cars.

Also in the article, it says this:
"With regards to the hydrodynamic conditions the bearing with an eccentricity is equivalent to the bearing with an increased diameter (or increased oil clearance). The oil wedge of the bearing with eccentricity is the same as the wedge formed by the bearing with an increased diameter (”effective bearing diameter”). On the other hand the actual bearing diameter is not changed..."

So my question is: could this reasoning explain BMW's use of tight con rod bearing clearances? The fact that they go higher on bearing eccentricity? Is that the point of this eccentricity test?

Sorry if these are dumb or repeated questions. I'm really trying to keep up!

Pat

[regular guy]

Originally Posted by catpat8000

I've been reading this article and have a question. It looks like the bearing eccentricity is well outside the range the article quotes for "passenger cars" and slightly higher than the range quoted for "high performance" cars.

Also in the article, it says this:
"With regards to the hydrodynamic conditions the bearing with an eccentricity is equivalent to the bearing with an increased diameter (or increased oil clearance). The oil wedge of the bearing with eccentricity is the same as the wedge formed by the bearing with an increased diameter (”effective bearing diameter”). On the other hand the actual bearing diameter is not changed..."

So my question is: could this reasoning explain BMW's use of tight con rod bearing clearances? The fact that they go higher on bearing eccentricity? Is that the point of this eccentricity test?

Sorry if these are dumb or repeated questions. I'm really trying to keep up!

Pat

Sounds plausible to me. Let's see what Kawasaki comes up with for real measurements, then we'll have a better picture of this topic.

[swamp2]

Originally Posted by catpat8000

I've been reading this article and have a question. It looks like the bearing eccentricity is well outside the range the article quotes for "passenger cars" and slightly higher than the range quoted for "high performance" cars.
...
So my question is: could this reasoning explain BMW's use of tight con rod bearing clearances? The fact that they go higher on bearing eccentricity? Is that the point of this eccentricity test?

It could be one factor on BMWs side that they know about and was part of the design that enables tighter than normal clearances. However, a few tenths (for the sake of simplicity just added to the existing clearance) does not get ratios as tight at 0.0006 in/in anywhere near the 0.0015 in/in minimum Clevite spec.

1. These number are preliminary based on used parts. Thus the new part numbers are more likely to be closer to the standard.
2. 3/8 ths of the shells are within the spec.
3. The spec is just like the Clevite spec, a basic guideline not a firm unbreakable rule.
4. The spec is pretty wide - a factor of 2, as are the measured values.

I like the thinking and again would not be a bit surprised if it is a contributing factor to BMWs alleged way to tight spec, but I certainly don't think this solves the mystery.

[swamp2]

Originally Posted by jcolley

My frustation plays out in the manner in which these potential issues are discovered and the lack of any acknowledgement by the manufacturer or effort to improve. What makes these cars different is the emotion and passion from the enthusiasts who own them. I have to believe that the engineers at ///M have every bit of the same and it's hard to come to terms that in the end, willfully or not, they are bound by the rules of business and maintaining corporate image and profit margin. If these cars were marketed purely at die-hard enthusiasts, they could embrace subjects like this, work collaboratively with their consumers, and bolster their own reputation and sales doing so. But they're not; they market the cars with enough performance to hold our attention, but still civil enough to produce large enough numbers for mass consumption of much, much larger target audience. More than likely, corporate acknowledgement of this, or any other for that matter, potential problem with a product would damage either current sales or stock value. So until it reaches a point where not dealing with a problem becomes more expensive than dealing with it, the casual consumers and die-hards are equally let down. The difference is, the casual consumers will move on and those who really love and embraced the platform are left to figure out how to prolong it. It's really a rant against an inevitable thing, so I'll keep my tone in check better.

Again, if you haven't seen the great movie:

Your desire is understood and certainly partially shared yet at the same time it's also naive.

Originally Posted by jcolley

That was the point of starting the S85 failure registry. We have great data on total numbers produced, but little energy going into the figuring out the numerator. As mentioned by someone else, someone has the data already, but we'll never see it.

Who exactly has the data on S85 failure numbers? BMW only has them for in warranty vehicles.

Originally Posted by jcolley

Can we take action to try and mitigate the wear? Sure, run lighter oil and never less than 93 octane (US).

93 is generally not available to me. I'd run it exclusively if it were.

Originally Posted by jcolley

Again, apologies if coming across as hostile, it was not the intent. There's enough drama in this thread already, I'll just go back to reading and learning.

I didn't really find your post too hostile myself, I didn't really agree with it but I don't think it was "hostile". You've definitely contributed to this ongoing discussion and I'd encourage you to keep on doing so!

[FogCityM3]

Interesting. At WOT after 7,500 rpm, stock timing target is 32 degrees. At what point does advancing timing become too dangerous? Think most tuners don't target more than a couple of degrees higher than stock.

Originally Posted by SenorFunkyPants

So here it is...SFP theory V1.

Owners who have data logged their M3s report that with 91Aki fuel the ionic current system is constantly pulling the timing to counter detonation. A key question, would you expect a car running constantly at the edge of detonation to put more load on the rod bearing environment than the same car running normally on 93 Aki all else being equal? I don't know, what is certain though is that as octane levels fall so will the ability of the ionic current anti knock system to efficiently control detonation as the combustion event becomes more chaotic. One tank of 87 octane alone could be sufficient to cause significant accelerated wear on the rod bearings with no other impact other than to be present when the engine is opened up at some time in the future.

© Pants industries.

[SenorFunkyPants]

Originally Posted by FogCityM3

Interesting. At WOT after 7,500 rpm, stock timing target is 32 degrees. At what point does advancing timing become too dangerous? Think most tuners don't target more than a couple of degrees higher than stock.

I've also read that in a stock car, 32 degrees is the max advance and also that there is a fixed amount of retardation that the ECU will apply to counter detonation and once you have reached that point, that is it (apparently the ECU can adapt to run 90 Aki fuel).
You do have to wonder about the benefit of trying to add extra degrees of advance to a engine that is already having to pull back the timing to hold it at the edge of detonation on 91 Aki at high load...Surely the only performance benefit would be if this then translated into less retardation of the timing as the ionic current sensing system was trying to control detonation....and that would not seem to be a good idea at all in the long term.
Also back a hundred posts or so when Yellow Snow queried why we aren't seeing any recorded engine failures in the UK...fuel was the only thing that occurred to me. But there is something else, UK owners as a rule don't tend to modify their engines in new or newish expensive cars like the M3. The demographic for the typical new UK M3 owner is for a much older professional compared to that say of California.
So here is an thought...could it be that the reason that Ca sees more than its fair share of failures is due to the fact that an M3 is far more likely to be (engine) modded in California than anywhere else in the world? Which when combined with 91 Aki only further increases the potential for damage.
It would also help account for why most undamaged engines that are opened find increased bearing wear....as who else is most likely to open up an engine (in preparation to say fit a supercharger) than someone who is into engine modifications and may well have run some sort of tune.
Bit of a stretch but it might be a factor.

[SenorFunkyPants]

Originally Posted by jcolley

A few minutes of searching over there yields a few more:

http://www.m5board.com/vbulletin/e60...lp-advice.html

Here's the UK failure:
http://www.m5board.com/vbulletin/e60...hese-v10s.html

http://www.m5board.com/vbulletin/e60...wn-engine.html

http://www.m5board.com/vbulletin/e60...ml#post1782187

http://www.m5board.com/vbulletin/e60...se-advice.html

http://www.m5board.com/vbulletin/e60...ml#post2270701

as well as the registry I was trying to start:

http://www.m5board.com/vbulletin/e60...-registry.html

Again, I'll be the first to state that not all were strictly bearing failures without cause.

This from a quick look.

M5 S85
Bearing failure - engine tune
Bearing failure at 143000 miles UK
Unknown cause of failure
Oil analysis only
Knock wasn't bearing.
Bearing failure maybe caused by Vanos oil pump failure. Engine tune
Bearing failure - engine tune
Bearing failure - engine tune
Bearing failure - engine tune
Bearing failure
Bearing failure
Bearing failure

12 cases. 10 USA, 1 SA 1 UK.
2 not a failure
1 unknown cause
1 suspected due to Vanos

8 failures where the cause was almost certainly bearing failure.
5 cars had some form of ECU tune.
3 cars that don't state a tune.

Thats not a lot of failures in stock cars.

[SenorFunkyPants]

Had another look at the S65 engine failure registry.
19 links on page 1.

1 failure due oil pump
1 rod snapped.
1 Cylinder/piston damage.
2 crankshaft failures
2 No failure.
2 Valve failures
3 failures of Supercharged engines
7 almost certain rod bearing failure

So there you go...its not as bad as you thought.

[gatorfast]

Originally Posted by SenorFunkyPants

So here is an thought...could it be that the reason that Ca sees more than its fair share of failures is due to the fact that an M3 is far more likely to be (engine) modded in California than anywhere else in the world? Which when combined with 91 Aki only further increases the potential for damage.
It would also help account for why most undamaged engines that are opened find increased bearing wear....as who else is most likely to open up an engine (in preparation to say fit a supercharger) than someone who is into engine modifications and may well have run some sort of tune.
Bit of a stretch but it might be a factor.

It would be interesting to hear some tuners chime in on why their tunes are safe and would not contribute to engine damage.

[CSBM5]

Originally Posted by SenorFunkyPants

But there is something else, UK owners as a rule don't tend to modify their engines in new or newish expensive cars like the M3. The demographic for the typical new UK M3 owner is for a much older professional compared to that say of California.
So here is an thought...could it be that the reason that Ca sees more than its fair share of failures is due to the fact that an M3 is far more likely to be (engine) modded in California than anywhere else in the world?

The further thought has occurred to me about how "the typical driver" probably believes the moving redline is his/her actual guide to how far they can rev the engine at full throttle while it is warming up. Think about that for a moment. Unless one is a knowledgeable enthusiast or an engineer who understands fluid dynamics and lubrication, etc, the probability of someone driving a cold engine hard, perhaps very hard, goes up substantially - thinking of 20-something xbox/playstation raised non-technical based owners here. The type of owner who claims the best way to "break in" a car is to drive it very hard from mile one, goes on to internet quote a Montesa 2-stroke engine builder, and, in addition, the entire time is ignorant to the break-in requirements of the gears in the transmission, especially the important break-in of the bevel gears in the differential, not to mention the clutch discs which need a gradual, moderate break-in to achieve their rated torque capacity...

[catpat8000]

Originally Posted by gatorfast

It would be interesting to hear some tuners chime in on why their tunes are safe and would not contribute to engine damage.

There is no such thing as a "safe" tune. Otherwise tuners would offer drivetrain warranties and the OEMs wouldn't disqualify your warranty upon discovering you have one. Can anyone name a single tuner who will stand behind the factory warranty with their tune? If so, that's the only safe tune.

Factory tunes are set to optimize performance and safety over a broad set of parameters and conditions. A lot of analysis goes into setting up the factory parameters. Most tuners almost certainly don't have that level of investment nor do they have to stand behind their work, economically speaking.

Pat

[gatorfast]

Originally Posted by catpat8000

There is no such thing as a "safe" tune. Otherwise tuners would offer drivetrain warranties and the OEMs wouldn't disqualify your warranty upon discovering you have one. Can anyone name a single tuner who will stand behind the factory warranty with their tune? If so, that's the only safe tune.

Factory tunes are set to optimize performance and safety over a broad set of parameters and conditions. A lot of analysis goes into setting up the factory parameters. Most tuners almost certainly don't have that level of investment nor do they have to stand behind their work, economically speaking.

Pat

Im the sure the main tuners on this board would disagree. Hopefully they will chime in.

[SenorFunkyPants]

Originally Posted by gatorfast

It would be interesting to hear some tuners chime in on why their tunes are safe and would not contribute to engine damage.

I suppose that if there is not much wiggle room with the ignition timing then that leaves fueling....what can you do with that, run a bit richer?

[CSBM5]

Originally Posted by catpat8000

There is no such thing as a "safe" tune. Otherwise tuners would offer drivetrain warranties and the OEMs wouldn't disqualify your warranty upon discovering you have one. Can anyone name a single tuner who will stand behind the factory warranty with their tune? If so, that's the only safe tune.

I think Dinan is the only one who matches the factory warranty and is CARB certified too.

[aussiem3]

I would like to hear from Mike Benvo of BPM Sport as to what his thoughts are on this bearing issue especially with ECU modification. His tunes are very conservative compared to others. His input here will be invaluable. But for some unknown reason he is banned from this forum. Forums are all about knowledge sharing and helping each other out but some one on this forum has an axe to grind against Mike, and keep extending his ban even when he is not posting. Isn't that funny.

[thekurgan]

Originally Posted by aussiem3

I would like to hear from Mike Benvo of BPM Sport as to what his thoughts are on this bearing issue especially with ECU modification. His tunes are very conservative compared to others. His input here will be invaluable. But for some unknown reason he is banned from this forum. Forums are all about knowledge sharing and helping each other out but some one on this forum has an axe to grind against Mike, and keep extending his ban even when he is not posting. Isn't that funny.

hashtag: political-ban

[FogCityM3]

Agreed, would be interesting to hear from the major tuners. I have logged (on rolling road) timing with BPM tune and can attest to the conservative timing numbers ie 32-33 degrees at WOT. Would like to know at what point too much is too much before it gets dangerous for the engine.

Originally Posted by aussiem3

I would like to hear from Mike Benvo of BPM Sport as to what his thoughts are on this bearing issue especially with ECU modification. His tunes are very conservative compared to others. His input here will be invaluable. But for some unknown reason he is banned from this forum. Forums are all about knowledge sharing and helping each other out but some one on this forum has an axe to grind against Mike, and keep extending his ban even when he is not posting. Isn't that funny.

[swamp2]

Originally Posted by SenorFunkyPants

Also back a hundred posts or so when Yellow Snow queried why we aren't seeing any recorded engine failures in the UK...fuel was the only thing that occurred to me. But there is something else, UK owners as a rule don't tend to modify their engines in new or newish expensive cars like the M3. The demographic for the typical new UK M3 owner is for a much older professional compared to that say of California.
So here is an thought...could it be that the reason that Ca sees more than its fair share of failures is due to the fact that an M3 is far more likely to be (engine) modded in California than anywhere else in the world? Which when combined with 91 Aki only further increases the potential for damage.
It would also help account for why most undamaged engines that are opened find increased bearing wear....as who else is most likely to open up an engine (in preparation to say fit a supercharger) than someone who is into engine modifications and may well have run some sort of tune.
Bit of a stretch but it might be a factor.

Excellent post, the bold part is very similar to a post I just made in another bearing thread here.

Also great summaries in your posts following this one analyzing and summarizing the cases surrounding the reported S85 and S65 data sets. IIRC regular_guy claimed that no failures here were SC and many/most had no outward signs of problems. There appears to be a fairly large contradiction here??? This same line of reasoning led to my post here long ago in this thread asking why the heck are all of these bottom ends with "NO apparent problems" are being torn down for "inspection". I also made the incorrect claim that if you tear down an engine with outward signs of problem and then find problems, that should not be much of a surprise. regular_guy corrected this mistake of mine which I acknowledged. I think someone else here hinted/stated that one or more companies installing SCs REQUIRE bearing inspection/replacement.

regular_guy and SFP please resolve this somewhat glaring contradiction. According to SFP's review HALF or less than half of the cars are truly "no issues" engines inspected and found to have some significant bearing wear. Depends on if you do or don't want to count the damaged cranks and/or siezed/"grenade" cases.

For the S65:

~10 cars for the entire US/Canada production (no separate US figures) is 0.04%

~10 cars for the entire world production is a whopping 0.017%

[regular guy]

SFP is incorrectly lumping together failures that I never included in this discussion and should not be part of this discussion. I've tried to limit the scope of this discussion by excluding blown motors without photographic evidence or forensic failure analysis. The only exception also happens to be a primary focus of this article: bone stock motors with less than 25000 miles (not supercharged motors, and not broken valve springs). You will not notice any comments of mine in the 20+ threads being referenced by SFP. I also have not commented on them here because 1) they lacked relevance because 2) they lacked any evidence to actually discuss. Many of the threads he uses for evidence...contain absolutely no evidence. Those threads are filled with second and third hand hearsay on engines that were never disassembled, let alone photographed, or root caused for failure. Much of the conversations are simply "I think it's X" or "my dealer told me Y" -- even though the dealer never disassembled the motor and simply replaced it with a long/short block from BMW. That's an extremely low threashold of proof that is now incorrectly being considered as iron clad evidence in this discussion. In all of those threads, I only saw one example that related to this discussion as both 1) bearing related, and 2) had any evidence. The main bearing case was very close, but without looking at it further, I'm ambivalent whether it should be included or excluded.

To sum it up, basically everything he keeps bringing up doesn't contradict me because it's not what I've been talking about in the first place. Therefore these differences will always be irreconcscileable as long as I keep talking about apples and he keeps talking about oranges.

We should all be able to agree when we see a thread that says his valve spring broke, that it doesn't belong in this discussion.

[regular guy]

Originally Posted by SenorFunkyPants

I've also read that in a stock car, 32 degrees is the max advance and also that there is a fixed amount of retardation that the ECU will apply to counter detonation and once you have reached that point, that is it (apparently the ECU can adapt to run 90 Aki fuel).
You do have to wonder about the benefit of trying to add extra degrees of advance to a engine that is already having to pull back the timing to hold it at the edge of detonation on 91 Aki at high load...Surely the only performance benefit would be if this then translated into less retardation of the timing as the ionic current sensing system was trying to control detonation....and that would not seem to be a good idea at all in the long term.
Also back a hundred posts or so when Yellow Snow queried why we aren't seeing any recorded engine failures in the UK...fuel was the only thing that occurred to me. But there is something else, UK owners as a rule don't tend to modify their engines in new or newish expensive cars like the M3. The demographic for the typical new UK M3 owner is for a much older professional compared to that say of California.
So here is an thought...could it be that the reason that Ca sees more than its fair share of failures is due to the fact that an M3 is far more likely to be (engine) modded in California than anywhere else in the world? Which when combined with 91 Aki only further increases the potential for damage.
It would also help account for why most undamaged engines that are opened find increased bearing wear....as who else is most likely to open up an engine (in preparation to say fit a supercharger) than someone who is into engine modifications and may well have run some sort of tune.
Bit of a stretch but it might be a factor.

Would you be kind enough to tell us the MINIMUM AKI octane required to run a 12.0:1 compression ratio engine without a knock sensor, and without an advanced ECU spark management system? Once you find the answer, then could you please explain how any high compression engine can do it even with a knock sensor and advanced ECU spark management system? Then please explain why your theory doesn't hold up for other similarly high compression engines running on the same pump gas?

These are serious question you need to answer before your theory can even begin to be accepted. Just add these to the other 10+ unanswered questions.

-- Patiently awaiting some real answers --

[SenorFunkyPants]

Originally Posted by regular guy

SFP is incorrectly lumping together failures that I never included in this discussion and should not be part of this discussion.

In your preamble you wrote:
"The first one or two blown motors showed up on bone stock M3's as well. These cars were totally stock with very low mileage. As time went on, more and more blown motors showed up, again NA motors with low miles. It seemed if you made it past 25,000 miles, then your motor would likely survive the warranty period.
Various theories were discussed to explain this phenomena. The theories ranged from inferior oil pump design to bearing clearance issues."

*You* referenced blown motors at the start but now want to exclude them because the actual low failure rate doesn't suit your theory. If the expected outcome of a tight rod bearing clearance is not an eventual failure then there is no problem and the bearing clearance is fine....and what better ultimate indicator of a rod bearing problem is there is, if its not the failed engine rate?
To be fair I didn't made a forensic analysis of the engines listed in the registry of failed engines. I worked on a simple principle...if a reason was given for the failure other than rod bearing, I noted it. All other failures (specific and non specific) were listed as a rod bearing failure (ie the rod bearing failure rate could be lower but unlikely to be much higher - of the sample in question).