Official S65 Rod Bearing Condition Example Thread

[IamFODI]

Originally Posted by rantarM3

Perhaps I've missed it but it seems that no one has published a comprehensive S65 clearance analysis that takes into account the multitude of factors mentioned in the articles. Maybe there's a reason for that - who knows.

Consider this: The work done by BE -- which is widely and not-altogether-unreasonably considered definitive and complete -- was WAY more demanding and thorough than most people would even attempt. A truly comprehensive analysis would be vastly more demanding than that. That's a hell of a lot of time, money, and talent for something that isn't guaranteed to yield anything useful. I don't think we'll be seeing it any time soon.

[rantarM3]

Originally Posted by pbonsalb

Which means your bearings might be fine or might be excessively worn or might be on the verge of failure. Which condition are yours in?

I'm not too concerned about it. And trying to find a shop I'd trust enough to open the engine and replace the bearings here in Florida is like trying to find a monkey that doesn't like bananas. With my luck with shops here, the engine would probably blow right after the bearing replacement.

It's all about probabilities. Most S65's are still driving around on original bearings and they're not blowing up; sure some do, but most don't. Then consider the main bearings - you might replace the rod bearings but in what shape are the mains? The only way I'd do bearings is through a complete engine out rebuild.

[rantarM3]

Originally Posted by IamFODI

Consider this: The work done by BE -- which is widely and not-altogether-unreasonably considered definitive and complete -- was WAY more demanding and thorough than most people would even attempt. A truly comprehensive analysis would be vastly more demanding than that. That's a hell of a lot of time, money, and talent for something that isn't guaranteed to yield anything useful. I don't think we'll be seeing it any time soon.

I agree with you. The only ones that will do that analysis are those getting strokers built. As extensive as BE's work might be, it does not give me enough comfort to go ahead and just replace the rod bearings. That's just my opinion at this point in time.

[Willem3]

My bearings after 84.000km

[BimmerMan33]

Originally Posted by Willem3

My bearings after 84.000km

To me they appear to be a little more worn than others at this mileage...
What year is the car?
Does the car get driven a lot in traffic? Does it get to see the redline often?

Glad you got them changed
Now enjoy the car, with more peace of mind!

[Helmsman]

Originally Posted by BimmerMan33

To me they appear to be a little more worn than others at this mileage...
What year is the car?
Does the car get driven a lot in traffic? Does it get to see the redline often?

Glad you got them changed
Now enjoy the car, with more peace of mind!

Ha, all these bearing pictures! To me they look really quite good compared to most I've seen but there you go.

[Willem3]

The mechanic said the bearings looks fine for the mileage.

It’s a manual 2008 E90, having the car since 60k km.
Service history. every 10.000-15.000km service
No history of track use.
Driving style, drive the car all year round but only occasionally and fun rides.

No traffic use, very easy when cold en when its nicely warmed up I like the sound of the screaming V8, driving style is very 50% sporty and 50% cruising.

[Scharbag]

Originally Posted by BimmerMan33

Agree with Solo M Tech's post above, changing rod bearings is probably a band aid but with increased clearance bearings the band aid might last to 175-200K miles, at which point this platform would be quite old and most people might move on to other cars/newer M3s.
For those who still hang on to their cars, might then consider an engine out rebuild and refresh/upgrade a bunch of other engine components as well, including main bearings, maybe make it a stroker motor or other etc...

I am unsure why the following post has not been cited more often than it has.

Originally Posted by toolshed

This is my pics of BE rod bearing #8 after 50,000 km on M1 0W-40.
Looks like new.
Outside temps from -25C up to +30C.

That is what bearings should look like after 50,000KM. Zero wear. Even the Clevite tri-armour coating is intact.

There is also a very detailed thread discussing oil flow and how it is affected by bearing clearance here:

Originally Posted by AutoTalent

February 2017 update:

Table of Contents

• Testing Results: BE Bearings SP1527H
  • Overview
  • Cold/Warm Start Analysis
    • Cold/Warm Start Data
    • Cold Start Graphs
    • Warm Start Graphs
  • Oil Pressure Analysis
    • Average Oil Pressure at various temperatures vs. RPM
    • RPM of minimum oil pressure (4-BAR, 58-PSI)
    • Absolute Minimum Oil Pressure at various temperatures vs. RPM
    • Absolute Maximum Oil Pressure at various temperatures vs. RPM
  • Oil Flow Analysis
    • How oil flow changes with different oil temperatures and RPM
  • Average Oil Pressure and Oil Flow

Testing Results: BE Bearings SP1527HK

Current Snapshot: 2017-02-28

Previous Snapshots:

• 2017-01-31
• 2016-12-31
• 2016-11-30

Overview

Cold Start Analysis

Summary Oil Pressure, Oil Flow Tests

Once you start your car, have you ever wondered how long it takes for oil pressure to build and oil flow to start? This is the section that shows what it looks like.

The following chart amd graphs will show what it looks like from the time you press the "START" button to 30-seconds later. The chart shows how long from “START” until 70% and 90% oil pressure is attained. After analyzing some of the data, it appears the throttle input might have been influencing the maximum oil pressure and flow. Had I known this, I would have not introduced any throttle until 30+ seconds after starting the car.

BE Bearings


BMW Factory 702/703 Bearings

• Most likely outlying data caused to throttle input

Summary
According to this chart, the BE Bearings take less time to reach 70% and 90% oil pressure compared to their BMW OEM counterparts. Not only is it less time to reach full oil pressure, it seems significantly less time to reach full oil pressure. This is a bit of a shock to me and something I never expected to see.

Trend 2017-02
Two more temperature ranges showed improvement over previous baseline. No temperature ranges got worse.
Trend 2017-01
Three temperature ranges showed improvement over previous baseline, one temperature range gave back 0.1 second over previous baseline.
Trend 2016-12
Four of six temperature ranges showed improvement over previous baseline.

Cold Start Graphs

Summary
These graphs show both BE Bearing and BMW Factory bearings (as lighter colors). It's very clear from these graphs, that the oil pressure comes up faster with BE Bearings than BMW Factory bearings. Having oil pressure come up faster and lubricating the bearings is a huge benefit to reduce bearing wear and increase bearing longevity. This was an unexpected surprise that we didn't anticipate. The graphs also show no decrease in oil pressure over factory bearings. This should allay fears that increased clearance would decrease oil pressure, especially during this critical "Cold Start" time period.

Oil flow does seem to modestly increase as well. This was an anticipated outcome, but it's good to see it on the graphs.

Warm Start Graphs

Summary
The trend with continues from our Cold Start graphs to our Warm Start graphs. Oil pressure comes up faster with BE Bearings than BMW factory bearings. Oil flow shows modest increases as well, but we'd say this is fairly inconclusive -- especially above 80c. Those graphs contained too much throttle input, and we think that contaminates the results. Now that we know this, we will see if we can filter out the results containing too much throttle, and moving forward will capture results without any throttle until 30-seconds has passed since starting the engine.

Oil Pressure Analysis

Average Oil Pressure at various temperatures vs. RPM

These graphs show the oil pressure average of all available samples at various temperatures and throttle ranges over RPM. The graphs do change slightly between 5%, 30%, and 50% throttle. The primary graph, 50% throttle is shown here. Click the thumbnails of the other graphs to enlarge each one.

RPM of minimum oil pressure (4-BAR, 58-PSI)

If minimum oil operating oils pressure is 4-BAR (58 PSI), then it’s interesting to see on this graph at what RPM that goal is achieved. Again, that answer depends on oil temperature – as oil is more viscous and produces more pressure the colder it is. As these graphs show, the minimum operating oil pressure at minimum RPM appears to be right around 2500; that’s where we get minimum 4-bar pressure regardless of oil temperature.

The following chart shows average oil pressure vs. RPM. It shows what RPM achieves minimum recommended 4-BAR (58-PSI) oil pressure. This chart highlights areas that have increased performance, decreased performance, or stayed the same. Areas marked in GREEN show an increase in performance. Areas marked in RED show a decrease in performance. Everything else is unchanged.



Summary: There was one area of decreased performance, but multiple areas of increased performance. The increased performance is starting to make more sense after seeing how cold and warm starts come up to pressure quicker with BE Bearings than factory BMW bearings. The same phenomenon may be at play here, or may be something difference.

Trend 2017-02:

• 5% Throttle: no change
• 30% Throttle: no change
• 50% Throttle: No change, except there's now data for 110-110c

Trend 2017-01:

• 5% Throttle: no change
• 30% Throttle: no change
• 50% Throttle: returned to normal at 96-97c, 100-101c

Trend 2016-12:

• 5% Throttle: no change
• 30% Throttle: improved at 102-103c
• 50% Throttle: improved at 96-97c

Absolute Minimum Oil Pressure at various temperatures vs. RPM

So far, the data being shown are averages across millions of samples. But what about absolute minimum and absolute maximums?

These are the same set of graphs as above, but show the absolute minimums. The absolute minimums are the minimum oil pressures collected across all temperature ranges. They are graphed here to show just how low the pressure can go. Some of this may have been observed during hard cornering (more on that later). So it's hard to draw any hard conclusions based on these graphs. They are offered for informational purposes only to let the reader draw their own conclusions.

Absolute Maximum Oil Pressure at various temperatures vs. RPM

Conversely, the final graph in this set shows the absolute maximums. There's no need to show maximum graphs for different throttle levels because the maximums are absolute and every graph would be the same.

Oil Flow Analysis

How oil flow changes with different oil temperatures and RPM

These graphs show the oil flow average of all available samples at various temperatures and throttle ranges over RPM. The graphs do change slightly between 5%, 30%, and 50% throttle. The primary graph, 50% throttle is shown here. Click the thumbnails of the other graphs to enlarge each one.





Summary
Overall, oil flow increased with BE Bearings over factory BMW 702/703 bearings. For upper oil operating temperatures, the oil flow seems to have increased substantially. At lower oil operating temperatures, the results are inconclusive -- just by looking at the graphs.

Our hopes with BE Bearings were to allow a modest drop in oil pressure, so long as it was accompanied by an increase in oil flow. These graphs don't tell us much about pressure yet, but they do show rather significant increases in oil flow.

Trend 2017-02

• 5% Throttle: Oil flow at many temperatures improved. Both low temperature ranges and higher temperature ranges showed some improvement over the last snapshot.
• 30% Throttle: Oil flow at two lower RPM bands increased, and also increased at 89-90c. Oil flow @ 20-40c was slightly lower on mid-RPM ranges (0.25 GPM lower). All others appear to be about the same.
• 50% Throttle: Oil flow at all higher temperature ranges seemed to improve. In fact, oil flow at almost all temperature ranges seemed to improve. The only exception was the same one noted in the 30% sample: 20-40c was about 0.025 GPM lower.

Trend 2017-01

• 5% Throttle: Oil flow at all temperature ranges below 100c stayed about the same. Oil flow above 100c continues to get higher and higher, especially in the mid-RPM ranges; not so much, if any at high-RPM ranges though.
• 30% Throttle: Oil flow at all temperature ranges below 102c stayed about the same. Oil flow above 102c continues to get higher and higher, similar to 5% throttle observations.
• 50% Throttle: Same as 30% Throttle. Oil flow at mid-RPM to upper-RPM ranges for 100c and above shows nice gains.

Trend 2016-12

• 5% Throttle: As more data samples become available over time, the data starts to converge. Oil flow increased 0.25 - 0.50 GPM almost across the board in all temperature ranges and RPM bands.
• 30% Throttle: Same observations as 5% throttle.
• 50% Throttle: Same observations as 5% throttle.

Average Oil Pressure and Oil Flow

These graphs show the average oil pressure and average oil flow average of all samples between 98-119c, and throttle ranges over RPM. The graphs do change slightly between 5%, 30%, and 50% throttle. The primary graph, 50% throttle is shown here. Click the thumbnails of the other graphs to enlarge each one.





Summary
Primarily, we want to know if BE Bearings cause an average decrease in oil pressure, and if so: how much? We also want to know if the BE Bearings increase average oil flow, and if so: how much?

This is the graph answers both of those questions in a rather obvious way.

• Oil Pressure: Oil pressure does seem to decrease slightly with BE Bearings. This is most likely due to the extra clearance. But the amount of decrease is between 2-3 PSI, over a 70+ PSI average. Assuming the 73 PSI average, a 3 PSI pressure drop is equal to 4% of the total. Whether it was the 5%, 30%, or 50% throttle input, the results were all the same: a 2-3 PSI drop over a 73 PSI average. This is proof positive that the S65 variable displacement oil pump is doing its job.
• Oil Flow: The most significant change between factory and BE Bearings is the oil flow. We were hoping for a modest increase in oil flow to offset a modest decrease in oil pressure. But the resulting oil flow is nearly double with BE Bearings over the BMW 702/703 bearing counterparts. Having double oil flow over the bearing surface increases the wedge strength and keeps the bearings cooler. The results with BE Bearings seems to be a huge win, much bigger than any of us expected.

Trend 2017-02

• 5% Throttle: Oil pressure stayed about the same as the last sample. However, oil flow from 400-7600 RPM increased about another 0.25 - 0.50 GPM. This is another net increase of oil flow across the entire RPM range. This is '''VERY STRONG''' showing.
• 30% Throttle: Just like the 5% throttle, oil pressure stayed about the same as the last sample. Also like the 5% sample, oil flow from 400-7600 RPM increased about another 0.25 - 0.50 GPM. This is another net increase of oil flow across the entire RPM range. This is another '''VERY STRONG''' showing.
• 50% Throttle: Results at 50% throttle match results at 30% throttle. Oil pressure stayed about the same, but oil flow from 400-7600 gained about another 0.25 - 0.50 GPM.

Trend 2017-01

• 5% Throttle: Oil pressure showed about a 1-PSI drop in high mid-to-upper RPM ranges. However, oil flow made very strong gains in the same area and all the way to high RPMs. Oil flow increased approximately 1-GPM over the last sample period. This is a VERY STRONG showing.
• 30% Throttle: Like 5% throttle, oil pressure showed about a 0.5 to 1-PSI drop in mid-RPM ranges. Oil flow also made very strong gains in the same area and all the way to high RPMs. Oil flow increased approximately 0.75-GPM over the last sample period. This is another VERY STRONG showing.
• 50% Throttle: Same results as 5% and 50% throttle, with oil flow increasing about 0.5 - 0.75 GPM instead of 0.75 - 1.0 GPM.

Trend 2016-12

• 5% Throttle: As more data samples become available over time, the data starts to converge. Oil pressure began to converge to BMW 702 pressure levels. What was a 2-3 PSI drop with BE Bearings, has gone down so about a 2.5 PSI drop. Oil flow showed a reasonable increase in all RPM bands above 5000. The wild variations seen in previous data start to disappear as more data samples are available.
• 30% Throttle: Oil pressure got smoother, but otherwise didn't change enough to mention. Oil flow showed a reasonable increase in all RPM bands above 4000.
• 50% Throttle: Oil pressure got smoother, but otherwise didn't change enough to mention. Oil flow showed a reasonable increase in all RPM bands above 3600.

I would suggest that there is enough information available to support that changing the rod bearings is not a band-aid, but a solution to the rod bearing problem. All of the data is available for anyone to analyse however they see fit.

Yes, replacing rod bearings does not address main bearing clearance concerns. That said, the main bearings have not been shown to be a significant problem on the S65 as very few main bearing only failures have been documented IIRC. Perhaps someone could chime in on the actual numbers if they have them handy.

To conclude: inadequate rod bearing clearance will lead to premature bearing failure, and likely a ruined engine. Certainly, it will be an engine-out repair.

Statistics and probability demand that a certain percentage of S65 engines have less than acceptable rod bearing clearance. Installing any rod bearing that establishes appropriate bearing clearance will resolve THAT specific problem.

Cheers,

[pbonsalb]

There are only several posts of replaced rod bearings. Not enough to draw any conclusions yet. There is one showing nice looking replaced WPC treated bearings, there is one showing nice looking VAC coated bearings, and there is one showing nice looking BE bearings.

[IamFODI]

One bearing shell from one engine after 30k miles, not even clean in the pic, and that's supposed to confirm a solution for all bearings in thousands of engines for 60k-100k+ miles?

[Scharbag]

Originally Posted by pbonsalb

There are only several posts of replaced rod bearings. Not enough to draw any conclusions yet. There is one showing nice looking replaced WPC treated bearings, there is one showing nice looking VAC coated bearings, and there is one showing nice looking BE bearings.

I know one example does not prove a solution. It simply shows that the solution is performing as expected.

Take the flow data and photos for what it is worth and draw your own conclusions. The photo shows, but it does not prove, that the BE bearing is doing EXACTLY what it was designed to do: operate as a proper hydrodynamic bearing. That is a good start.

I really do look forward to more people pulling BE bearings with high mileage from their engines to show how they perform. Given the fundamentals followed by BE, I would suggest they will look great in all cases. If I am wrong, I am wrong.

Personally, I choose to put my trust in the professional engine builders who identified the issue, measured a number of engines, designed the new bearings, tested the solution and shared the data with us. I am not saying to anyone that BE is the ONLY solution. That was a personal choice I made. IMHO, if we do not support people like BE now, why would anyone go through the effort they did in the future?

What I am saying is that when replacing your rod bearings, the choice should be one with proper clearance. There are a few different choices on the market at this time that offer increased clearance. Pick the one you comfortable with and install them.

Cheers,

[pbonsalb]

You could say the picture of the WPC bearings, which had more miles on them, show that stock clearance is fine and that just WPC treatment is needed. And you could say the picture of the VAC coated stock bearing, the mileage of which I don’t recall but Malek posted it a couple of years ago, shows that just a coating is needed even if it slightly reduces stock clearance.

I think replacing the bearings is a good choice, and that probably the later VAC increased clearance bearings, the BE increased clearance bearings and the ACL increased clearance bearings are an even better choice.

[NeverL8]

Originally Posted by pbonsalb

You could say the picture of the WPC bearings, which had more miles on them, show that stock clearance is fine and that just WPC treatment is needed. And you could say the picture of the VAC coated stock bearing, the mileage of which I don’t recall but Malek posted it a couple of years ago, shows that just a coating is needed even if it slightly reduces stock clearance.

I think replacing the bearings is a good choice, and that probably the later VAC increased clearance bearings, the BE increased clearance bearings and the ACL increased clearance bearings are an even better choice.

I believe those VAC bearing that Malek pulled had ~35k miles on them and they were extra clearance ones

[RedScytheM3]

Originally Posted by Scharbag

I am unsure why the following post has not been cited more often than it has.

That is what bearings should look like after 50,000KM. Zero wear. Even the Clevite tri-armour coating is intact.

There is also a very detailed thread discussing oil flow and how it is affected by bearing clearance here:

I would suggest that there is enough information available to support that changing the rod bearings is not a band-aid, but a solution to the rod bearing problem. All of the data is available for anyone to analyse however they see fit.

Yes, replacing rod bearings does not address main bearing clearance concerns. That said, the main bearings have not been shown to be a significant problem on the S65 as very few main bearing only failures have been documented IIRC. Perhaps someone could chime in on the actual numbers if they have them handy.

To conclude: inadequate rod bearing clearance will lead to premature bearing failure, and likely a ruined engine. Certainly, it will be an engine-out repair.

Statistics and probability demand that a certain percentage of S65 engines have less than acceptable rod bearing clearance. Installing any rod bearing that establishes appropriate bearing clearance will resolve THAT specific problem.

Cheers,

Aside from those bearings being beautiful after that much work, people, wear gloves when you handle used oil!

[strokemycocktus]

Here's a post I found on MRF Engineering Facebook page, showing WPC bearings removed after just 3k miles. Aside from the cyl 1 which is smashed, all the rest seems to be also wearing pretty badly.
I wonder which bolts were used there.

https://www.facebook.com/mrfengineer...type=3&theater

[eswaroop]

Any good shop recommended to get the rod bearings done here near Austin Texas ?

[deansbimmer]

Originally Posted by eswaroop

Any good shop recommended to get the rod bearings done here near Austin Texas ?

Our shop is in Dallas. We get Austin/Houston folks driving up all the time.

[RedScytheM3]

Originally Posted by deansbimmer

Our shop is in Dallas. We get Austin/Houston folks driving up all the time.

This is perfect for me. I live in Houston and have family in Dallas (:

[eswaroop]

I don’t know if this has been answered before but if there’s abnormal bearing wear due to tight clearances doesn’t the problem self correct after some wear?

Or is it a downhill process that once wear starts it doesn’t stop?

[pbonsalb]

That has been raised before. Probably to some degree it is true, or at least true that wear slows after that initial wear. It is also possible that once you wear away the surface of the bearing that is designed to maintain the oil film, the film may not be as correct and friction may go up.

[deansbimmer]

Originally Posted by eswaroop

I don’t know if this has been answered before but if there’s abnormal bearing wear due to tight clearances doesn’t the problem self correct after some wear?

Or is it a downhill process that once wear starts it doesn’t stop?

I've seen this "self correction" concept spread around on FB pages and it only spreads misinformation.

There is a designed bore shape that the bearing is supposed to maintain through its life. An inadequate oil clearance causing erosion of the bearing surface is not desirable and affects how the hydrodynamic bearing oil wedge functions. Since the wear does not occur to the entire 360 degrees of the journal surface, the bore shape becomes more eccentric over time which has undesirable effects to its function.

Additionally, this abnormal wear is removing the soft babbit layer of the bearing surface which is intended to embed debris that may otherwise damage the crankshaft journal or other parts. With excessive wear removing the soft babbit and exposing the harder binding layers, the risk of debris scoring the journals and leading to seizure increases exponentially.

There is a great document here about how bearings work here. Especially note page 4 on this topic.
http://kingbearings.com/files/Engine..._They_Work.pdf

[eswaroop]

Originally Posted by deansbimmer

I've seen this "self correction" concept spread around on FB pages and it only spreads misinformation.

There is a designed bore shape that the bearing is supposed to maintain through its life. An inadequate oil clearance causing erosion of the bearing surface is not desirable and affects how the hydrodynamic bearing oil wedge functions. Since the wear does not occur to the entire 360 degrees of the journal surface, the bore shape becomes more eccentric over time which has undesirable effects to its function.

Additionally, this abnormal wear is removing the soft babbit layer of the bearing surface which is intended to embed debris that may otherwise damage the crankshaft journal or other parts. With excessive wear removing the soft babbit and exposing the harder binding layers, the risk of debris scoring the journals and leading to seizure increases exponentially.

There is a great document here about how bearings work here. Especially note page 4 on this topic.
http://kingbearings.com/files/Engine..._They_Work.pdf

Thank for sharing - good info there! So how do the new bearings address the issue? Are they harder material (which seems to be detrimental from the article) or are they built with more clearance ? (Which could make things worse if the original tolerances properly stacked up for a particular car ) Or are they replacing the worn parts but not necessarily addressing the issue longer term and will need to be eventually replaced again)