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      01-08-2014, 12:09 AM   #1783
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It was early November when I had some work done. Yes, I knew about the ownership change, but Steve Dinan is still intimately involved in the business.

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When was this? How recently? Dinan sold the company about six months ago. Steve Dinan is no longer the owner. They are big corporation owned now.
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      01-08-2014, 01:14 AM   #1784
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When was this? How recently? Dinan sold the company about six months ago. Steve Dinan is no longer the owner. They are big corporation owned now.
That's fascinating! I had no idea. Do you know who bought the company?

Edit: Wikipedia says B&M Racing & Performance Inc.

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      01-08-2014, 01:19 AM   #1785
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Bearing Eccentricity

Article: Geometrical parameters of engine bearings
Article: Hydrodynamic Bearings
Article: Fundamentals of Fluid Film Journal Bearing Operation and Modeling


I've got to be honest, I didn't know anything about bearing eccentricity when I created this thread, and I doubt I'll be able to add any insight into the subject. As I learned, the bearing is not round, it is slightly oval shaped. The bearing clearance is the smallest at 90 degrees to the parting line, and largest at the parting line. This ratio between the two is called "eccentricity" and as I understand it is designed to allow oil to escape and be replenished. If there is too little eccentricity, it would be harder for oil to esscape. If the oil doesn't escape then the trapped oil can become super heated and cause both bearing and connecting rod damage. This could be one explanation why connecting rods such as the ones below shows signs of super heating that lead to catastrophic failures.





According to the first article above, these are values one could expect to measure for bearing eccentricity:
For passenger cars: 0.0002 - 0.0008” For high performance cars: 0.0006 - 0.0012”
The values above represent a fixed value, not a ratio of rod journal diameter or surface area. So to me, that spec above doesn't make sense. I would expect it to be more of a ratio of journal surface area instead of a fixed value. Regardless, the information above is valuable for our understanding.

Where to measure

According to the article above, I should measure eccentricity at 3/8 inch above the parting line for journals between 1.6 - 3.4 inch diameter. At first, this is not what I did. I had completed the measurements and I had already written 90% of this article and prepared 100% of the charts and graphs. But the perfectionist in me wouldn't let it go. The 702/703's were still installed in the rods, so I quickly took the measurements. The following night, I replaced the 702/703's with the 088/089's and took those measurements too.

Marking and Measuring

For this article, I had measured at 5, 45, 90, 135, and 175 degrees on 088/089 and 702/703 bearings. To capture the "official" eccentricity measurements according to the abovementioned article, I also measured at 20 and 160 degrees as well. Before taking any measurements, I did some quick calculations and marked the connecting rod locations as shown below.





088/089 Bearing Eccentricity (while measuring)






702/703 Bearing Eccentricity (while practicing)







Data Results
088/089 Bearing Results

Bearing Bore Measurements by Angle

088/089 Ecc. Meas.
R1
R2
R3
R4
R5
R6
R7
R8
MIN
Max
Official
Min Dev.
Max Dev.
005 Degrees
2.05070
2.05040
2.05035
2.05055
2.05060
2.05050
2.05035
2.05050
2.05035
2.05070
2.05049
-0.00014
0.00021
020 Degrees
2.04860
2.04860
2.04880
2.04880
2.04880
2.04885
2.04885
2.04885
2.04860
2.04885
2.04877
-0.00017
0.00008
045 Degrees
2.04815
2.04800
2.04840
2.04815
2.04830
2.04805
2.04835
2.04830
2.04800
2.04840
2.04821
-0.00021
0.00019
090 Degrees
2.04785
2.04790
2.04795
2.04795
2.04800
2.04795
2.04800
2.04800
2.04785
2.04800
2.04795
-0.00010
0.00005
135 Degrees
2.04800
2.04820
2.04820
2.04840
2.04820
2.04810
2.04840
2.04820
2.04800
2.04840
2.04821
-0.00021
0.00019
160 Degrees
2.04860
2.04860
2.04880
2.04870
2.04885
2.04880
2.04870
2.04885
2.04860
2.04885
2.04874
-0.00014
0.00011
175 Degrees
2.05060
2.05100
2.05035
2.05060
2.05055
2.05015
2.05050
2.05055
2.05015
2.05100
2.05054
-0.00039
0.00046


Bearing Clearance Measurements by Angle

088/089 Ecc. Clr.
R1
R2
R3
R4
R5
R6
R7
R8
MIN
Max
Official
Min Dev.
Max Dev.
005 Degrees
0.00285
0.00250
0.00240
0.00260
0.00260
0.00255
0.00235
0.00250
0.00235
0.00285
0.00254
-0.00019
0.00031
020 Degrees
0.00075
0.00070
0.00085
0.00085
0.00080
0.00090
0.00085
0.00085
0.00070
0.00090
0.00085
-0.00015
0.00005
045 Degrees
0.00030
0.00010
0.00045
0.00020
0.00030
0.00010
0.00035
0.00030
0.00010
0.00045
0.00026
-0.00016
0.00019
090 Degrees
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
135 Degrees
0.00015
0.00030
0.00025
0.00045
0.00020
0.00015
0.00040
0.00020
0.00015
0.00045
0.00026
-0.00011
0.00019
160 Degrees
0.00075
0.00070
0.00085
0.00075
0.00085
0.00085
0.00070
0.00085
0.00070
0.00085
0.00079
-0.00009
0.00006
175 Degrees
0.00275
0.00310
0.00240
0.00265
0.00255
0.00220
0.00250
0.00255
0.00220
0.00310
0.00259
-0.00039
0.00051


Complete 088/089 Bearing Specifications with Eccentricity

EngineS65B40
Bearing Dimensions (088/089 Bearings)Metric DimensionsSAE (Inch) Dimensions
Rod + Bearing Dimensions52.0180 mm2.04795 inch
Rod + Bearing Variance (1)52.0141 - 52.0281 mm2.04780 - 2.04835 inch
Nominal Rod Bearing Clearance0.0357 mm0.00140 inch
Bearing Clearance Variance (1)0.0305 - 0.0470 mm0.00120 - 00185 inch
Bearing Clearance Tolerance-0.0051 - +0.0114 mm-0.00020, +0.00045 inch
Bearing Clearance per Journal inch0.00068 inch/inch
Bearing Clearance per Journal Inch Variance (1)0.00059 - 0.00090 inch/inch
Bearing Eccentricity0.0203 mm0.00080 inch
Bearing Eccentricity Variance0.0178 - 0.0216 mm0.00070 - 0.00085 inch
Bearing Eccentricity Tolerance-0.0038, +0.0013 mm-0.00015, +0.00005 inch


702/703Bearing Results

Bearing Bore Measurements by Angle

702/703 Ecc. Meas.
R1
R2
R3
R4
R5
R6
R7
R8
MIN
Max
Official
Min Dev.
Max Dev.
005 Degrees
2.05280
2.05290
2.05290
2.05280
2.05250
2.05260
2.05270
2.05290
2.05250
2.05290
2.05276
-0.00026
0.00014
020 Degrees
2.05045
2.05035
2.05035
2.05020
2.05010
2.05020
2.05035
2.05035
2.05010
2.05045
2.05029
-0.00019
0.00016
045 Degrees
2.04900
2.04880
2.04880
2.04920
2.04870
2.04890
2.04880
2.04890
2.04870
2.04920
2.04889
-0.00019
0.00031
090 Degrees
2.04830
2.04815
2.04840
2.04820
2.04835
2.04830
2.04820
2.04820
2.04815
2.04840
2.04820
-0.00005
0.00020
135 Degrees
2.04900
2.04890
2.04900
2.04885
2.04900
2.04890
2.04890
2.04885
2.04885
2.04900
2.04893
-0.00007
0.00008
160 Degrees
2.05035
2.05045
2.05035
2.05020
2.05040
2.05040
2.05035
2.05020
2.05020
2.05045
2.05034
-0.00014
0.00011
175 Degrees
2.05280
2.05300
2.05270
2.05280
2.05285
2.05290
2.05285
2.05300
2.05270
2.05300
2.05286
-0.00016
0.00014


Bearing Bore Measurements by Angle

702/703 Ecc. Clr.
R1
R2
R3
R4
R5
R6
R7
R8
MIN
Max
Official
Min Dev.
Max Dev.
005 Degrees
0.00450
0.00475
0.00450
0.00460
0.00415
0.00430
0.00450
0.00470
0.00415
0.00475
0.00450
-0.00035
0.00025
020 Degrees
0.00215
0.00220
0.00195
0.00200
0.00175
0.00190
0.00215
0.00215
0.00175
0.00220
0.00215
-0.00040
0.00005
045 Degrees
0.00070
0.00065
0.00040
0.00100
0.00035
0.00060
0.00060
0.00070
0.00035
0.00100
0.00063
-0.00027
0.00037
090 Degrees
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
135 Degrees
0.00070
0.00075
0.00060
0.00065
0.00065
0.00060
0.00070
0.00065
0.00060
0.00075
0.00066
-0.00006
0.00009
160 Degrees
0.00205
0.00230
0.00195
0.00200
0.00205
0.00210
0.00215
0.00200
0.00195
0.00230
0.00200
-0.00005
0.00030
175 Degrees
0.00450
0.00485
0.00430
0.00460
0.00450
0.00460
0.00465
0.00480
0.00430
0.00485
0.00460
-0.00030
0.00025


Complete 702/703 Bearing Specifications with Eccentricity

EngineS65B40
Bearing Dimensions (702/703 Bearings)Metric DimensionsSAE (Inch) Dimensions
Rod + Bearing Dimensions52.0243 mm2.04820 inch
Rod + Bearing Variance52.0230 - 52.0294mm2.04815 - 2.04840 inch
Nominal Rod Bearing Clearance0.0419 mm0.00165 inch
Bearing Clearance Variance0.0394 - 0.0483 mm0.00155 - 0.00190 inch
Bearing Clearance Tolerance-0.0025 - +0.0064 mm-.00010 - 0.00025 inch
Bearing Clearance per Journal inch0.00081 inch/inch
Bearing Clearance per Journal Inch Variance0.00076 - 0.00093 inch/inch
Bearing Eccentricity0.0508 mm0.00200 inch
Bearing Eccentricity Variance0.0445 - 0.0584 mm0.00175 - 0.00230 inch
Bearing Eccentricity Tolerance-0.0064, +0.0076 mm-0.00025, +0.00030 inch


Even in this manner, it's hard to get a feel for the data. So graphing is the only way to look at it to see what's really going on. Even though the charts and specifications all say there's a difference, just what does it look like on a graph?

Graphs and Conclusions

I created the graphcs as a scatter plot with a "best fit" polynomial line to follow the contour of the measurements. That's when the results really jumped out and you could visually see for the first time how these bearings have changed. Not only did the bearing clearance change between 088/089 and 702/703, but so did the eccentricity. The eccentricity didn't change by a little, it seems to have changed by a LOT! See for yourself.

"Common" Eccentricity


Conclusions and my $0.02

When I was asked to measure bearing eccentricity, I had no idea what I would find. I guess I presumed that 088/089 bearings would both follow the same guidelines and show the same eccentricity. Even when I was measuring and looking at the numbers, I was making that presumption and didn't notice any differences. It wasn't until I looked at the graph that it became very obvious that something radical had changed.

The bearing eccentricity changed from 0.00085 inch on the 088/089 bearings to 0.00200 inch on the 702/703 bearings. That's a 2.5 times increase in eccentricity clearance which will allow the oil to escape the rods that much better.

It wasn't too long ago that I thought there was only one bearing part number. But that proved wrong! Between the S85 and S65 lifespan there were a total of FOUR different bearing designs, but I believe only two of those ever saw production on the S65. The older designs are long gone and we'll never get a fresh set of those bearings to test and see how they differ from these (I already tried).

After I discovered the new bearing designs (702/703's), I thought they shared the same dimensions as the originals (088/089's). But that proved wrong too. These new measurements proved that the 702/703 bearings changed material, clearance, and pretty radically changed eccentricity.

By now I think I have a much clearer picture than when I started. Some will say (and have already said) that the 702/703 bearings changed dimensions because of the materials change. I've got to be honest, that sounds very compelling on the surface but there's one thing about it that really bugs me. Nobody has explained why the harder material would require extra clearance when 1) the bearing is never supposed to touch the journal, and 2) it would seem that it has less friction than the older lead/copper design. So to me, the dimensional changes of the new bearing weren't based on a simple materials change, but were much more deliberate.

The S65 started production with 088/089 bearings. But something was wrong: relatively new engines were puking connecting rods. The clearances were too tight, the side clearance was too tight, the eccentricity was too tight, and the oil was too thick. As a result, it seems like tolerance stack up with a bad luck of the draw, and your engine might end up looking like the photos shown above. So BMW decided to do something about it.

When BMW designed the newer 702/703 bearings to comply with lead-free regulations, they made changes. I believe they took steps to mitigate these problems. BMW increased the rod bearing clearance, and they increased the eccentricity by 250%. Those changes mean two of the four possible "trouble spots" I mentioned above have now been addressed.

In August 2013, BMW-NA made a specification change to the oil allowed in the S85/S65. After five years of only allowing 10W60, BMW relaxed the specifications and is now allowing LL-01 approved 0W40, 5W30, and 5W40 weight oils. Three of the four potential trouble areas we identified in the S65 have now been addressed. The only thing that remains is the rod side clearance. With the help of some buddies down the road, I might be able to take measurements on a wide range of BMW S65 crankshafts to see if the rod side clearance has changed throughout the three different crankshafts manufactured for the S65. If that comes to pass, I'll be sure to post the results either way (changed side clearance or not).

Van Dyne identified two of the four potential problems (journal clearance, rod side clearance), Kawasaki00 and BMWLVR were advocates for thinner oils, and we really kind of backed in to the eccentricity discussion and discovered a big change eccentricity clearances.

Some will say it's all a coincidence. They are just as entitled to their opinion as I am mine. I don't think it's a coincidence. For whatever reason, BMW changed (coincidence or not), BMW had three years with old bearing; then three years with new bearings; then changed to allow thinner oils. Sure it may all be a coincidence, but to me, it seems like they were chasing something and were making incremental changes to mitigate what they saw as a problem.

Blast away.

Last edited by regular guy; 01-09-2014 at 07:52 PM.
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      01-08-2014, 01:42 AM   #1786
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RG, first of all thanks for all your time and dedication to this topic.

The eccentricity results are far greater then I had expected. I get your point on what your saying about how BMW has made changes to clearance and oil and what that suggests (that they made a mistake).

However, the only reason why BMW changed to lead/copper free bearings is due to EU regulations. It does not conclude that they did it because something was wrong, they made the change in material because they were following government guidelines.

Thats like saying auto manufactures are choosing turbo engines over NA because its better, its not better and its not their first choice. Its what they are required to do to stay in business.
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      01-08-2014, 01:44 AM   #1787
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Three truths changed from:

Three truths of S65 bearing/side clearance
There are three things we seem to know for a fact:
  1. There is a long standing clearance-to-journal ratio best practice rule that factory and racing engine builders alike have followed for 50+ years. This best practice clearance ratio is well documented in many of web sites, and recommended by Clevite, the maker of the S65 engine bearings. The S65 engine cuts that clearance ratio in half. (1, 2)

To:

Three truths of S65 bearing/side clearance
There are three things we seem to know for a fact:
  1. There is a long standing clearance-to-journal ratio best practice rule that factory and racing engine builders alike have followed for 50+ years. This best practice clearance ratio is well documented in many of web sites, and recommended by Clevite, the maker of three years worth of S65 engine bearings. The S65 clearance ratio for 2008 - ~2010 engines is smaller than this minimum recommended best practice value. (1, 2)
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      01-08-2014, 01:54 AM   #1788
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If BMW were in fact chasing down a problem to mitigate litigation risk by limiting engine oil recommendations, they're doing a terrible job doing so: 1) ambiguously worded info release on newly approved oils; 2) direct questions about LL-1 to BMW NA are given non-or cryptic responses, including reiteration of 10w-60 as the recommended oil; 3) dealers, despite being shown the release, insisting on using 10w-60. The collective impact of which is unlikely to cause the vast majority of people to change to LL-1

Instead, one would expect a large corporation such as BMW to better mitigate risk by making the new oil recommendations unambiguous, by BMW NA directly answering customer questions about LL-1 being approved and safe for the engine, and by dealers getting a clear message from corporate that LL-1 is perfectly fine and is carried in stock.
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      01-08-2014, 04:57 AM   #1789
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Quote:
Originally Posted by regular guy View Post
Some will say (and have already said) that the 702/703 bearings changed dimensions because of the materials change. I've got to be honest, that sounds very compelling on the surface but there's one thing about it that really bugs me. Nobody has explained why the harder material would require extra clearance when 1) the bearing is never supposed to touch the journal, and 2) it would seem that it has less friction than the older lead/copper design. So to me, the dimensional changes of the new bearing weren't based on a simple materials change, but were much more deliberate.
A softer lead faced bearing can run a tighter clearance because they are less sensitive to tolerance, misalignment and other issues as should there be any metal to metal contact the softer outer lead layer is sacrificed not the crank journal surface (as would be if using a harder bearing surface). True, in principle, the bearing is not supposed to touch the journal but it is well known (even to BMW) that in real life it can.
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      01-08-2014, 10:28 AM   #1790
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Quote:
Originally Posted by SenorFunkyPants View Post
swamp2: Will not
SFP: Should Not.
Based on the man at BMW telling me it was only a materials change and not a dimension change.
Quote:
Originally Posted by SenorFunkyPants View Post
A softer lead faced bearing can run a tighter clearance because they are less sensitive to tolerance, misalignment and other issues as should there be any metal to metal contact the softer outer lead layer is sacrificed not the crank journal surface (as would be if using a harder bearing surface). True, in principle, the bearing is not supposed to touch the journal but it is well known (even to BMW) that in real life it can.
Only 11 days ago you swore an oath on your supreme contact at BMW that the bearing specifications, dimensions, and clearances haven't changed between 088/089 and 702/703 bearings. But today, it's "magically" expected due to materials change.

Just curious if you have any "magical" sources of data to back that up? Can you compare to other engines before/after to back it up also?

Sorry for the sarcasm, but I'm on a roll in a moment.
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      01-08-2014, 11:48 AM   #1791
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Quote:
Originally Posted by regular guy View Post
The bearing eccentricity changed from 0.00085 inch on the 088/089 bearings to 0.00200 inch on the 702/703 bearings. That's a 2.5 times increase in eccentricity clearance which will allow the oil to escape the rods that much better.

After I discovered the new bearing designs (702/703's), I thought they shared the same dimensions as the originals (088/089's). But that proved wrong too. These new measurements proved that the 702/703 bearings changed material, clearance, and pretty radically changed eccentricity.

By now I think I have a much clearer picture than when I started. Some will say (and have already said) that the 702/703 bearings changed dimensions because of the materials change.

Blast away.
Huge thanks Robert for your massive amount of work. We've all learned a bunch, primarily based on your persistence. I agree with you - the eccentricity change seems far too massive to be coincidental or accidental or a side effect.

Quote:
Originally Posted by 96LTWM3 View Post

However, the only reason why BMW changed to lead/copper free bearings is due to EU regulations. It does not conclude that they did it because something was wrong, they made the change in material because they were following government guidelines.

Thats like saying auto manufactures are choosing turbo engines over NA because its better, its not better and its not their first choice. Its what they are required to do to stay in business.
Yes, BMW changed bearing material because of regulations. But that isn't to say they didn't take advantage of this bearing change already coming to make some other changes, like in eccentricity for example.

Quote:
Originally Posted by FogCityM3 View Post
If BMW were in fact chasing down a problem to mitigate litigation risk by limiting engine oil recommendations, they're doing a terrible job doing so: 1) ambiguously worded info release on newly approved oils; 2) direct questions about LL-1 to BMW NA are given non-or cryptic responses, including reiteration of 10w-60 as the recommended oil; 3) dealers, despite being shown the release, insisting on using 10w-60. The collective impact of which is unlikely to cause the vast majority of people to change to LL-1

Instead, one would expect a large corporation such as BMW to better mitigate risk by making the new oil recommendations unambiguous, by BMW NA directly answering customer questions about LL-1 being approved and safe for the engine, and by dealers getting a clear message from corporate that LL-1 is perfectly fine and is carried in stock.
LOL, I don't know what really happened with the oil change but if you think that large corporations easily manage communications and don't often mess up, you would be mistaken. In this case, the vast majority of owners won't even be aware of the changes so not getting things right and clear doesn't have any real drawback.

Lastly, in following along with this thread, I am reminded of the harsh difference between BMW and Chevrolet, with respect to its enthusiasts. The forum equivalent to bimmerpost for Corvette owners is corvetteforum. And in that forum, GM has a presence. They answer questions, they provide information, and they are generally quite involved with the forum community. See these two threads for examples - GM is posting under the moniker of "Chevy Cust Svc". In one of them, GM admits to a fault in the LS7 causing many LS7s to fail.

http://forums.corvetteforum.com/c6-z...post1582048497

http://forums.corvetteforum.com/c6-c...post1585763039

Food for thought BMW.

Last edited by catpat8000; 01-08-2014 at 12:27 PM.
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      01-08-2014, 12:06 PM   #1792
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Sorry, while I recognize that large companies make mistakes all the time, for something as simple/easy as this, I don't buy the excuse unless they are REALLY incompetent. Product litigation and recalls are the fatal flaw of consumer automotive companies and cadres of lawyers and litigation consultants are employed by this industry.

Also, let's assume that BMW changed oil recommendations due to bearing issues, in part brought about by this thread (the timing of the change was highly coincidental maybe too coincidental), which they are probably monitoring. Given what has been pointed out in terms of poor risk management by a major corporation with potential litigation liabilities, one would expect that BMW would give more clear oil recommendations in the near future. Let's see if they do. If they don't and the bearing failure rate is greater than average or God forbid, an engine seizes and causes injury to others, there will likely be litigation and this thread and all its contents will be subpoenaed.

Quote:
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LOL, I don't know what really happened with the oil change but if you think that large corporations easily manage communications and don't often mess up, you would be mistaken. In this case, the vast majority of owners won't even be aware of the changes so not getting things right and clear doesn't have any real drawback.


http://forums.corvetteforum.com/c6-z...post1582048497

http://forums.corvetteforum.com/c6-c...post1585763039

Food for thought BMW.
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      01-08-2014, 12:13 PM   #1793
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Thanks RG…. Impressive findings and commitment
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      01-08-2014, 12:17 PM   #1794
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Sorry, while I recognize that large companies make mistakes all the time, for something as simple/easy as this, I don't buy the excuse unless they are REALLY incompetent. Product litigation and recalls are the fatal flaw of consumer automotive companies and cadres of lawyers and litigation consultants are employed by this industry.

Also, let's assume that BMW changed oil recommendations due to bearing issues, in part brought about by this thread (the timing of the change was highly coincidental maybe too coincidental), which they are probably monitoring. Given what has been pointed out in terms of poor risk management by a major corporation with potential litigation liabilities, one would expect that BMW would give more clear oil recommendations in the near future. Let's see if they do. If they don't and the bearing failure rate is greater than average or God forbid, an engine seizes and causes injury to others, there will likely be litigation and this thread and all its contents will be subpoenaed.
Others have pointed out that the ambiguous oil change wording is intentional to AVOID litigation. They say if BMW were to make the announcement unambiguous and say it's to mitigate a design "flaw" or "limitation" then it would INCREASE the risk of litigation and class action lawsuit. Hench the ambiguous wording.

I would subscribe to that same belief.
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      01-08-2014, 12:19 PM   #1795
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Huge thanks Robert for your massive amount of work. We've all learned a bunch, primarily based on your persistence. I agree with you - the eccentricity change seems far too massive to be coincidental or accidental or a side effect.
Thanks Pat. I learned a lot doing this as well. It's really been eye opening to me too.

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Thanks RG…. Impressive findings and commitment
You're welcome. Thanks for participating.
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      01-08-2014, 12:24 PM   #1796
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Also, let's assume that BMW changed oil recommendations due to bearing issues, in part brought about by this thread (the timing of the change was highly coincidental maybe too coincidental), which they are probably monitoring.
Also highly coincidental that the president of BMWNA was tooling around a "shop" asking questions.
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      01-08-2014, 12:26 PM   #1797
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Thanks Pat. I learned a lot doing this as well. It's really been eye opening to me too.



You're welcome. Thanks for participating.
Good to see that we agree on how to use a dial bore gauge
Some are still not convinced that two people 3k miles apart can come to virtually the same conclusion.
Appreciate all the work you have done.
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      01-08-2014, 12:39 PM   #1798
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Good to see that we agree on how to use a dial bore gauge
Some are still not convinced that two people 3k miles apart can come to virtually the same conclusion.
Appreciate all the work you have done.
Thank you SOOOO much for all your help. Since the eccentricity is way beyond my area of expertise, I'm wondering if you can comment on it a little. I'm really curious why the huge change and how close I was to correct analysis of what it means.
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      01-08-2014, 12:53 PM   #1799
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The hardest part to digest is the fact BMW has a history with rod bearing issues on past motors. You would think the last thing this motor would have is a problem with its bearings. I actually thought about that prior to purchase. I figured thankfully that won't be issue this time. I find it unacceptable that BMotorW got it wrong. These cars cost a lot of money, at least for me, and this should be a none issue in my book. Thanks everyone for their technical input on this matter.
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      01-08-2014, 01:01 PM   #1800
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Thank you so much for all the work and effort put into this!
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      01-08-2014, 01:14 PM   #1801
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Did.
Did.
Did.

Yes there is. I'll post that next.
As mentioned previously, I quite enjoy being proven wrong when there is proof and thanks to you and the additional funding from the folks here we have that proof.

On a loosely related note I would be quite surprised if the new bearings had a radically reduced capability to capture and embed small particles. It is such an essential feature of journal style bearings.
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      01-08-2014, 01:33 PM   #1802
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Thank you SOOOO much for all your help. Since the eccentricity is way beyond my area of expertise, I'm wondering if you can comment on it a little. I'm really curious why the huge change and how close I was to correct analysis of what it means.
I sure can, give me a day to get some free time.

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As mentioned previously, I quite enjoy being proven wrong when there is proof and thanks to you and the additional funding from the folks here we have that proof.

On a loosely related note I would be quite surprised if the new bearings had a radically reduced capability to capture and embed small particles. It is such an essential feature of journal style bearings.
I agree on this, from our experience that is a drawback of the harder bearing. It is much easier damaged from trash floating around in the system. I have wondered, if the clearance is greater then what is throwing rods out of what seems like the newer cars more than the older cars. The older ones are delaminating and wearing out but the new ones seem to grab and kick the rod out. There was a post on here about a guy that changed his bearings and you could see the large amount of debris that floated through and really damaged the bearing. The filter seems pretty good on the s65. Some of these cheap oil filters on cars really dont filter much, they just sit on the bypass all the time.
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      01-08-2014, 02:15 PM   #1803
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[The 702/703's were still installed in the rods, so I quickly took the measurements. The following night, I replaced the 702/703's with the 088/089's and took those measurements too.
Looks very good so far RG. I think I'm quite close to a fairly strong reversal of my prior overall speculation on this topic.

However, part of bearing installation is a permanent yielding (deformation) of the bearings (called crush). Wouldn't it be a no-no and potentially large source of error to remove and reinstall the 088/089 bearings, measuring only the diameter at 90° in the initial install and then eccentricity after a removal and reinstall? Obviously those older bearings were tough to impossible to get. I'm sure kawasaki00 can provide additional guidance here (not my area of expertise also). If this is an issue, perhaps a quick verification test with 702/703s might be in order (i.e. is eccentricity affected by removal and reinstallaton).

Also on a loosely related point, I was certain that someone mentioned prior in this thread that Clevite is not the S65 bearing manufacturer. That was the source of my prior comment on that particular point.

Also, any idea on if eccentricity can be closely and approximately measured on a new uninstalled bearing? I wouldn't think that eccentricity is due solely to yielding/crush during installation. There must also be a variation in thickness along the virgin bearing shells.

Lastly on the eccentricity and flow. Your description seems a bit imprecise, it is not that small clearances or small eccentricity will stop the flow, it would just reduce the flow. Thus in any given time interval providing less flow rate and hence less cooler oil and cooling.

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      01-08-2014, 02:52 PM   #1804
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It's a shame that eccentricity wasn't mentioned earlier in the thread. It would have saved sooo much time.

Great job RG

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