Official S65 Bearing Specification/Clearance Wiki

[regular guy]

Originally Posted by swamp2

It's not that mode is incorrect, it is just non-standard and less mathematically useful. My response suggesting mode was only putting into words your preference for choosing the most common value, even back then I suggested mean. Either way, since you are generous and thorough enough with the original measurement, its not at all a big deal if mean and standard deviation and the like are missing. Cheers.

OK, I understand what you're saying. I was always thinking of two things, but which make MODE sound more useful to me. 1) I wanted to find the most likely value BMW chose themselves. It seems like the most commonly occuring number would be that value. 2) I wanted people to be able to verify my measurements with similar equipment. Using MEAN instead of MODE would make that less likely. So for me, it still sounds like MODE is what I'm looking for. It also sounds like anybody who wants the mean and stddev can get them from the data I presented -- since all of the data is there in the open.

[catpat8000]

Originally Posted by regular guy

It also sounds like anybody who wants the mean and stddev can get them from the data I presented -- since all of the data is there in the open.

Yes, as long as the basic measurements are there, anyone can calculate the mean, variance, std deviation, etc.

[regular guy]

Great Bearing Measurements of 2014

Preparation for clearance measurements

I wanted the clearance measurements to be as controlled as possible. To me, this meant following the manufacturer’s specification and maintaining a proper and controlled temperature environment. Each bearing was installed in the rod and the rod bolts were properly stretched. The fitted rods were placed out on an open table along with the measuring equipment for two hours before measuring. The room temperatures were set to approximately 74-77 degrees Fahrenheit to match the conditions at Van Dyne Engineering during the original tests. (To be honest, I didn't have my portable weather gauge with me at Van Dyne during the original tests, so I'm only guestimating the original temperature.) I am hoping these procedures will gain uniformity between all of the temperatures, measurements, and measuring equipment.

Selecting bearing pairs to match rod bearing bores

I wanted to simulate the possible effects of tolerance stack up. So before beginning to assemble the rods and bearings, I had previously measured all of the rod bearing bores. These measurements were as follows:

	R1	R2	R3	R4	R5	R6	R7	R8	MIN	Max	Official	Min Dev.	Max Dev.
Rod B.E. Bore	2.20530	2.20520	2.20520	2.20530	2.20530	2.20520	2.20520	2.20520	2.20520	2.20530	2.20520	0.00000	0.00010
Rod B.E. Thickness	0.72505	0.72515	0.72445	0.72500	0.72480	0.72520	0.72465	0.72450	0.72445	0.72520	0.72500	-0.00055	0.00020

To simulate the tolerance stack up, I wanted to select bearings as described below. Since it might not be possible to simulate all combinations, the following table describes my order of preference.

• Small rod bore + thicker bearings
• Small rod bore + nominal bearings
• Nominal rod bore + nominal bearings
• Large rod bore + thicker bearings
• Large rod bore + nominal bearings
• Nominal rod bore + thicker bearings

Using these criteria above, I came up with the following rod/bearing combinations.

702/703 Stack Up	R1	R2	R3	R4	R5	R6	R7	R8	MIN	Max	Official	Min Dev.	Max Dev.
Rod B.E. Bore	2.20530	2.20520	2.20520	2.20530	2.20530	2.20520	2.20520	2.20520	2.20520	2.20530	2.20520	0.00000	0.00010
Top (Blue)	0.07870	0.07870	0.07865	0.07865	0.07865	0.07865	0.07865	0.07865	0.07865	0.07870	0.07865	0.00000	0.00005
Bottom (Red)	0.07855	0.07855	0.07850	0.07850	0.07850	0.07855	0.07850	0.07850	0.07850	0.07855	0.07850	0.00000	0.00005
Combined Thickness	0.15725	0.15725	0.15715	0.15715	0.15715	0.15720	0.15715	0.15715	0.15715	0.15725	0.15715	0.00000	0.00010
Bore - CT	2.04805	2.04795	2.04805	2.04815	2.04815	2.04800	2.04805	2.04805	2.04795	2.04815	2.04805	-0.00010	0.00010
Bearing ID's (top/bottom)	V08/V02	V03/V05	V01/V01	V02/V03	V04/V04	V05/V06	V06/V07	V07/V08

088/089 Stack Up	R1	R2	R3	R4	R5	R6	R7	R8	MIN	Max	Official	Min Dev.	Max Dev.
Rod B.E. Bore	2.20530	2.20520	2.20520	2.20530	2.20530	2.20520	2.20520	2.20520	2.20520	2.20530	2.20520	0.00000	0.00010
Top (Blue)	0.07890	0.07890	0.07885	0.07880	0.07885	0.07885	0.07885	0.07885	0.07880	0.07890	0.07885	-0.00005	0.00005
Bottom (Red)	0.07875	0.07880	0.07860	0.07860	0.07865	0.07865	0.07865	0.07865	0.07860	0.07880	0.07865	-0.00005	0.00015
Combined Thickness	0.15765	0.15770	0.15745	0.15740	0.15750	0.15750	0.15750	0.15750	0.15740	0.15770	0.15750	-0.00010	0.00020
Bore - CT	2.04765	2.04750	2.04775	2.04790	2.04780	2.04770	2.04770	2.04770	2.04750	2.04790	2.04770	-0.00020	0.00020
Bearing ID's (top/bottom)	V03/220.07	V01/220.03	V02/Z03	V08/Z07	V04/Z02	V05/Z04	V06/Z05	V07/Z06

Stretching rod bolts and installing bearings

Both sets of bearings (702/703 and 088/089) were given new rod bolts so the tests would be as equal as possible. New S65 rod bolts must be stretched before use. The stretching procedure is very specific. You must torque and release two times prior to final torque and use. The following procedure is documented in the BMS TIS guide for building the S65 engine.

Replace screws Screws washed and oiled
1. Jointing torque	6 Nm
2. Setting torque	20 Nm
3. Angle of rotation	130-Degrees
Important 4. Release connecting rod bolts.
5. Jointing torque	6 Nm
6. Setting torque	20 Nm
7. Angle of rotation	130-Degrees
Important 8. Release connecting rod bolts.
9. Jointing torque	6 Nm
10. Setting torque	20 Nm
11. Angle of rotation	130-Degrees

This procedure would normally require two different tools. First you would need to use the torque wrench to torque to 6 NM then 20 NM. Second you would need to change to the torque angle gauge. The pictures below show the procedure with a normal (albeit electronic) torque wrench + torque angle gauge.



The normal procedure shown above is good, but is prone to minor errors. That type of torque angle gauge is can slip a little -- making the torque angle less accurate. This error happened to me repeatedly while stretching the rod bolts. So before the final rod bolt stretch, I decided it was time to upgrade my torque wrench anyways. I bought the all-in-one electronic Snapon ATECH3FR250B TECHANGLE torque wrench/torque angle gauge. This is a very nice torque wrench that is capable of switching between torque and torque angle. The electronics in the device make it possible to switch between units of torque at the press of a button (ft-lbs, in-lbs, Nm, dNm, Kcgm, and torque angle). The wrench supports different pre-sets too. So I was able to set the 20 Nm on one setting, then hit the button and switch to 130 degree torque angle. With this tool, there is no need to switch between two different devices.

Before the final stretch, all the rod bolts were completely removed. Each bolt was re-oiled, and the rod bolt under-cap was re-oiled as well. This ensures no galling could take place and an accurate final setting. The vice is also fitted with hard rubber boots to prevent damage to the connecting rods when they are clamped in.











Final Preparations

I'm almost ready to begin measuring. There's just a few more things I need to do. I promised to provide eccentricity measurements, so I need to mark the connecting rods at 5, 45, 90, 135, and 175 degrees.





Before measuring, I let all of the rods sit for two hours in the open air room temperature with thermostat set to ~76 degrees. The measuring equipment sits at the same location at the same temperatures. The Kestrel 4500 portable weather station is the small green device sitting on the lower left near rod #5 in the first photo, and upper left near rod #1 in the second photo. You see these on TV shows like Deadliest Catch. They are very nice and very accurate. This particular model will data log all environmental conditions and allows me to take individual snapshots in addition to a continuous data logs.



Last but not least, after letting everything sit for a few hours, I re-measured the crankshaft journals. No surprises here, they measured exactly the same as before, although in a different order. By that I mean, the measurement spread was identical to before, but the measurements seemed to change order on the journals. When you're talking about measuring tenths (0.00010 inch) and half-tenths (0.00005 inch), I'm told this is quite normal. Just to make sure, I called Van Dyne for advice. Van Dyne told me: "If you try to understand it and don't ignore it, you'll never get anything done."

Crank Journals	R1	R2	R3	R4	R5	R6	R7	R8	MIN	Max	Official	Min Dev.	Max Dev.
New	2.04655	2.04660	2.04660	2.04655	2.04655	2.04655	2.04655	2.04650	2.04650	2.04660	2.04655	-0.00005	0.00005
Old	2.04655	2.04650	2.04655	2.04660	2.04650	2.04655	2.04660	2.04650	2.04650	2.04660	2.04655	-0.00005	0.00005

The Results:
088/089 Bearing Clearances

Calibration and set up:

088/089 Results	R1	R2	R3	R4	R5	R6	R7	R8	MIN	Max	Official	Min Dev.	Max Dev.
Rod B.E. Bore	2.20530	2.20520	2.20520	2.20530	2.20530	2.20520	2.20520	2.20520	2.20520	2.20530	2.20520	0.00000	0.00010
Top (Blue)	0.07890	0.07890	0.07885	0.07880	0.07885	0.07885	0.07885	0.07885	0.07880	0.07890	0.07885	-0.00005	0.00005
Bottom (Red)	0.07875	0.07880	0.07860	0.07860	0.07865	0.07865	0.07865	0.07865	0.07860	0.07880	0.07865	-0.00005	0.00015
Combined Thickness	0.15765	0.15770	0.15745	0.15740	0.15750	0.15750	0.15750	0.15750	0.15740	0.15770	0.15750	-0.00010	0.00020
Bore - CT	2.04765	2.04750	2.04775	2.04790	2.04780	2.04770	2.04770	2.04770	2.04750	2.04790	2.04770	-0.00020	0.00020
Bearing Measurements	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
Nominal Bearing Clearance	0.00130	0.00135	0.00140	0.00140	0.00145	0.00140	0.00145	0.00145	0.00130	0.00145	0.00140	-0.00015	0.00010
Min Stack Up Clearance	0.00125	0.00130	0.00135	0.00135	0.00140	0.00135	0.00140	0.00140	0.00125
Max Stack Up Clearance	0.00135	0.00140	0.00145	0.00145	0.00150	0.00145	0.00150	0.00150		0.00150
Bearing ID's (top/bottom)	V03/220.07	V01/220.03	V02/Z03	V08/Z07	V04/Z02	V05/Z04	V06/Z05	V07/Z06
Bearing ID Photos
Clearance Photos

Official 088/089 Bearing Thickness and Clearance Specifications

Engine	S65B40
Bearing Dimensions (088/089 Bearings)	Metric Dimensions	SAE (Inch) Dimensions
Rod + Bearing Dimensions	52.0180 mm	2.04795 inch
Rod + Bearing Variance (1)	52.0141 - 52.0281 mm	2.04780 - 2.04835 inch
Nominal Rod Bearing Clearance	0.0357 mm	0.00140 inch
Bearing Clearance Variance (1)	0.0305 - 0.0470 mm	0.00120 - 00185 inch
Bearing Clearance Tolerance	-0.0051 - +0.0114 mm	-0.00020, +0.00045 inch
Bearing Clearance per Journal inch		0.00068 inch/inch
Bearing Clearance per Journal Inch Variance (1)		0.00059 - 0.00090 inch/inch
Nominal Bearing Thickness (Top, Blue)	2.0028 mm	0.07885 inch
Nominal Bearing Thickness (Bottom, Red)	1.9977 mm	0.07865 inch
Bearing Thickness Variance (Top, Blue)	2.0015 - 2.0041 mm	0.07880 - 0.07890 inch
Bearing Thickness Variance (Bottom, Red)	1.9964 - 2.0015 mm	0.07860 - 0.07880 inch
Bearing Tolerance (Top, Blue)	-0.0013, +0.0013 mm	-0.00005, +0.00005 inch
Bearing Tolerance (Bottom, Red)	-0.0013, +0.0038 mm	-0.00005, +0.00015 inch

Notes: (1) Includes previous measurement results from Van Dyne Engineering

When comparing to the original Van Dyne measurements, there seem to be no surprises here. The crankshaft journals measured within the same ranges, as did the connecting rod + bearing assemblies. With the addition of the newer virgin 089 bearings, I have changed the "official" estimate of 0.00125 inch clearance to 0.00140 inch clearance. That's a 0.00015 inch increase over the previous nominal measurements. That increases the nominal clearance-to-journal/inch ratio from 0.00061 inch/inch to 0.00068 inch/inch, which is still lower than the minimum Clevite recommendation of 0.00075 inch/inch.

702/703 Bearing Clearances

Calibration and set up:

702/703 Results	R1	R2	R3	R4	R5	R6	R7	R8	MIN	Max	Official	Min Dev.	Max Dev.
Rod B.E. Bore	2.20530	2.20520	2.20520	2.20530	2.20530	2.20520	2.20520	2.20520	2.20520	2.20530	2.20520	0.00000	0.00010
Top (Blue)	0.07870	0.07870	0.07865	0.07865	0.07865	0.07865	0.07865	0.07865	0.07865	0.07870	0.07865	0.00000	0.00005
Bottom (Red)	0.07855	0.07855	0.07850	0.07850	0.07850	0.07855	0.07850	0.07850	0.07850	0.07855	0.07850	0.00000	0.00005
Combined Thickness	0.15725	0.15725	0.15715	0.15715	0.15715	0.15720	0.15715	0.15715	0.15715	0.15725	0.15715	0.00000	0.00010
Bore - CT	2.04805	2.04795	2.04805	2.04815	2.04815	2.04800	2.04805	2.04805	2.04795	2.04815	2.04805	-0.00010	0.00010
Bearing Measurements	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
Nominal Bearing Clearance	0.00175	0.00160	0.00185	0.00165	0.00180	0.00175	0.00165	0.00165	0.00160	0.00185	0.00165	-0.00010	0.00025
Min Stack Up Clearance	0.00170	0.00155	0.00180	0.00160	0.00175	0.00170	0.00160	0.00160	0.00155
Max Stack Up Clearance	0.00180	0.00165	0.00190	0.00170	0.00185	0.00180	0.00170	0.00170		0.00190
Bearing ID's (top/bottom)	V08/V02	V03/V05	V01/V01	V02/V03	V04/V04	V05/V06	V06/V07	V07/V08
Bearing ID Photos
Clearance Photos

Official 702/703 Bearing Thickness and Clearance Specifications

Engine	S65B40
Bearing Dimensions (702/703 Bearings)	Metric Dimensions	SAE (Inch) Dimensions
Rod + Bearing Dimensions	52.0243 mm	2.04820 inch
Rod + Bearing Variance	52.0230 - 52.0294mm	2.04815 - 2.04840 inch
Nominal Rod Bearing Clearance	0.0419 mm	0.00165 inch
Bearing Clearance Variance	0.0394 - 0.0483 mm	0.00155 - 0.00190 inch
Bearing Clearance Tolerance	-0.0025 - +0.0064 mm	-.00010 - 0.00025 inch
Bearing Clearance per Journal inch		0.00081 inch/inch
Bearing Clearance per Journal Inch Variance		0.00076 - 0.00093 inch/inch
Nominal Bearing Thickness (Top, Blue)	1.9977 mm	0.07865 inch
Nominal Bearing Thickness (Bottom, Red)	1.9939 mm	0.07850 inch
Bearing Thickness Variance (Top, Blue)	1.9977 - 1.9990 mm	0.07865 - 0.07870 inch
Bearing Thickness Variance (Bottom, Red)	1.9939 - 1.9952 mm	0.07850 - 0.07855 inch
Bearing Tolerance (Top, Blue)	-0.0000, +0.0013 mm	-0.00000, +0.00005 inch
Bearing Tolerance (Bottom, Red)	-0.0000, +0.0013 mm	-0.00000, +0.00005 inch

For me, there were no surprises here as well. Kawasaki00 had measured a full set of 702/703 rods with better equipment and detected a 0.00030 inch increase in clearance. The measurements above confirm that, and found a 0.00025 inch increase in clearance (effectively the same thing as kawasaki00's findings).

Conclusions

This was an enormous amount of work. I tried to be as meticulous as possible. I was willing to let the data show, what the data shows. There are some slight inconsistencies and deviations from the previous measurements, but those deviations are in the noise (0.00005 differences). All in all, everything turned out the same.

Putting together the charts and tables is very time consuming work. There was a lot of cut-paste from one table to another. Even though I tried to cross reference very data entry with photos, it's very possible I made some mistakes here when I cut-paste some entries. If any such errors are found, please point them out and I will fix them.

The front page clearances have been updated to reflect these new findings.

Still to come:

1. I have finished the eccentricity measurements. I believe that topic requires a separate post of its own. There's a bunch of data, photos, and graphs to present. I'll leave you with this teaser: if the measurements above were no surprise, the eccentricity measurements might be. Stay tuned...hopefully I will have them posted later tonight.
2. I also have a set of Calico coated bearings. I will install, torque, and measure these in the coming weeks.
3. I plan to send out half of the 702/703's to Calico, and the other half to WPC. Plan to mark each bearing, and compare the results when they return. After they return, I will installed and remeasure to present the results.
4. Probably a few more things I'm forgetting at the moment.

[aus]

WOW!!!
Thanks for all that CRAZY work and the work you have planned ahead.

.

[Yellow Snow]

Originally Posted by regular guy

For me, there were no surprises here as well.

I'm a bit confused here. From your logs it seems there is a .00081" per inch rod clearance, which is in the middle of the Clevite recommendation.

Isn't this whole thread based around your claim that the clearance was way out of the Clevite 'Best practice' spec?

Nice torque wrench BTW

[regular guy]

Originally Posted by Yellow Snow

I'm a bit confused here. From your logs it seems there is a .00081" per inch rod clearance, which is in the middle of the Clevite recommendation.

Isn't this whole thread based around your claim that the clearance was way out of the Clevite 'Best practice' spec?

You already know the answer; why pretend like you don't? It's even the second or third time we've discussed it.

Why don't you tell me the answer this time?

Nice torque wrench BTW

Thanks.

[swamp2]

Nice work RG, a few comments, suggestions and observations.

But first...

Originally Posted by Yellow Snow

I'm a bit confused here. From your logs it seems there is a .00081" per inch rod clearance, which is in the middle of the Clevite recommendation.

Isn't this whole thread based around your claim that the clearance was way out of the Clevite 'Best practice' spec?

The older bearings are just outside of the Clevite spec (about 10% "tighter") but the newer ones are well inside it. Furthermore (not because you are claiming so but just as a preemptive point) any such specification is inherently based on a nominal value thus it is not appropriate to cherry pick the very tightest old (088/089) case at 0.00059 in/in and claim that to be radically outside of the 0.0075 in/in specification.

Also (as suggested prior) since Clevite is not the manufacturer for these bearings we really should not even be holding them to the exact same standard. Either way the notion that the S65 (rod bearing) clearances are radically tighter than this "norm" should now be pretty well laid to rest as false.

Unfortunately, the flip side to this is that BWM did either design in (most likely in my opinion or perhaps accepted as a consequence of manufacturing) a 20% increase (dead between my prior 15-25% estimate based on bearing thicknesses alone) in bearing clearance along with the update from the old (088/089) to new (702/703) bearings. Unfortunately, we'll most likely never know if this was some preemptive effort against premature bearing/engine failures. It seems reasonable that the material itself may simply have required a different actual clearance that is some way is more like the same initial clearance.

RG:

-Good job choosing bearings/bores etc to maximize variations. That was smart. It is interesting to note that even despite this choice the worst case clearance ratio for the 702/703 bearings was still larger than the minimum Clevite specification.

-"Official" really should not be used as a term. This is not a number off of a print, it is an observed sample population mean.

-"Nominal Bearing Clearance" also is not a nominal value, a nominal value is a print/design value simply without a tolerance". This should simply be called a Measured Clearance.

-What are Min and Max Stack Up Clearances? Are they just to account for the additional variation of +/- 0.0005 on the crank?

-Lastly it is a bit odd to also include the Van Dyne measurements here most notably because in the final white/grey tables some include those efforts and some don't.

Observations:

Not to much surprise the difference in the thicknesses of the bearings at 90° to parting directly contribute to the same reduction in installed bearing diameters and clearances. The observed old/new bearing total size difference was about 3.5 tenths difference and the old/new average clearances are different by 2.5 tenths.

There is no overlap in the clearances (total range with min/max values) in the tables for the old/new bearings. Also there is a similar and very large ratio of the difference in the mean clearances for the old/new compared to the standard deviation thus leaving no doubt that the consistency of the measurement is not an issue and is fully capturing a real difference in the assembled parts.

Again,

the notion that the S65 (rod bearing) clearances are radically tighter than the Clevite recommendation should now be pretty well laid to rest as false.

The obvious big remaining question then what is causing the failures on the later model cars that had the newer 702/703 bearings. Perhaps, it's just simple statistics and an unavoidable result of building an engine like the S65 for a mass produced sports sedan and the number of failures/total probability of failure is more or less in the noise (basically my contention all along old or new bearings...)

[swamp2]

Originally Posted by regular guy

You already know the answer; why pretend like you don't? It's even the second or third time we've discussed it.

Why don't you tell me the answer this time?

Although you have not been the strongest proponent of the theory that BMW completely screwed the pooch big time on clearances, you've clearly been in that camp. See below, which you have posted in one form or another a good half dozen times or more:

Originally Posted by regular guy

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)

...

Either way I also don't know the answer to YS's original question.

[BPMSport]

Originally Posted by swamp2

Although you have not been the strongest proponent of the theory that BMW completely screwed the pooch big time on clearances, you've clearly been in that camp. See below, which you have posted in one form or another a good half dozen times or more:

Seems like that's the case based on this post:
http://www.m3post.com/forums/showpos...4&postcount=32

Originally Posted by regular guy

1) BMW changed the spec and increased the clearance on rod bearings in 2011.
2) BMW changed spec on oil to 0W40 in August 2013.

Pretty clear where I'm sitting that BMW didn't think all was well, and that increasing clearance alone didn't fix whatever they were chasing. The question begs back to BMW: if it ain't broke, why did they try to fix it...twice?

I may agree with #1, but #2 I think is speculation at this point (plus it was not "changed" - meaning that the prior oil should no longer be used).

[DLSJ5]

Originally Posted by Mike Benvo

Seems like that's the case based on this post:
http://www.m3post.com/forums/showpos...4&postcount=32



I may agree with #1, but #2 I think is speculation at this point (plus it was not "changed" - meaning that the prior oil should no longer be used).

I think RG is smart enough to know that BMW and most of their dealers are still recommending 10W60 as there first choice. I think you're inferring that he means they only use 0W40 now and no longer 10W60? I didn't read his post that way, we all know that's not the case with TWS. I also know, despite his strong opinion on clearances, that RG has stated before that he doesn't think the vast majority of S65's will blow up from rod bearing failure.

[BPMSport]

Originally Posted by DLSJ5

I think RG is smart enough to know that BMW and most of their dealers are still recommending 10W60 as there first choice. I think you're inferring that he means they only use 0W40 now and no longer 10W60? I didn't read his post that way, we all know that's not the case with TWS. I also know, despite his strong opinion on clearances, that RG has stated before that he doesn't think the vast majority of S65's will blow up from rod bearing failure.

That's not what I was inferring at all. Read the thread in which his post was quoted from and it will make more sense in context. He's stated there that BMW has knowingly made a mistake on the clearances as well as their oil selection of 10w-60, by allowing thinner weight oils later in production. I don't believe that this conclusion is supported by enough evidence and that it's speculation at this point. Allowing 0w-40 is not necessarily a "fix" to an supposedly existing problem that they may be aware of.

Here it is: http://www.m3post.com/forums/showthread.php?t=931268

[DLSJ5]

Originally Posted by Mike Benvo

That's not what I was inferring at all. Read the thread in which his post was quoted from and it will make more sense in context. He's stated there that BMW has knowingly made a mistake on the clearances as well as their oil selection of 10w-60, by allowing thinner weight oils later in production. I don't believe that this conclusion is supported by enough evidence and that it's speculation at this point. Allowing 0w-40 is not necessarily a "fix" to an supposedly existing problem that they may be aware of.

Here it is: http://www.m3post.com/forums/showthread.php?t=931268

Mike, you inferred that RG was claiming that BMW changed the spec to 0W40 instead of 10W60, seeing as your late to the party in this discussion, I can see why you'd infer that, if that's not what you're saying it's cool, I have ZERO desire to discuss anymore what you said or didn't say. BUT, I do agree with you that it's speculation to assume they did it solely because of tight clearances or issues they may be having with bearings, but I also believe that it's a huge coincidence that they did, move along and lets let the experts like RG, Swamp, Kawasaki and the others continue their good work.

[regular guy]

Originally Posted by Mike Benvo

Seems like that's the case based on this post:
http://www.m3post.com/forums/showpos...4&postcount=32

I may agree with #1, but #2 I think is speculation at this point (plus it was not "changed" - meaning that the prior oil should no longer be used).

I don't mind having a hypertechnical debate. But if we do that...here's where it goes.

Since none of us work at BMW and have direct access to the information, that means ALL of our opinions are speculation...your above opinion as well.

Yes "it" was changed. The list of allowed oils changed from strictly TWS-10W60 to TWS-10W60 + all LL01 oils.

[regular guy]

Originally Posted by Mike Benvo

That's not what I was inferring at all. Read the thread in which his post was quoted from and it will make more sense in context. He's stated there that BMW has knowingly made a mistake on the clearances as well as their oil selection of 10w-60, by allowing thinner weight oils later in production. I don't believe that this conclusion is supported by enough evidence and that it's speculation at this point. Allowing 0w-40 is not necessarily a "fix" to an supposedly existing problem that they may be aware of.

Here it is: http://www.m3post.com/forums/showthread.php?t=931268

I did not say or imply any such thing. Let's not "speculate" on what I meant...if I did not say it. I'm usually very literal.

[BPMSport]

Originally Posted by DLSJ5

Mike, you inferred that RG was claiming that BMW changed the spec to 0W40 instead of 10W60, seeing as your late to the party in this discussion, I can see why you'd infer that, if that's not what you're saying it's cool, I have ZERO desire to discuss anymore what you said or didn't say. BUT, I do agree with you that it's speculation to assume they did it solely because of tight clearances or issues they may be having with bearings, but I also believe that it's a huge coincidence that they did, move along and lets let the experts like RG, Swamp, Kawasaki and the others continue their good work.

I quote RG from the other thread
"2) BMW changed spec on oil to 0W40 in August 2013."

There is a difference between CHANGING the spec, and ADDING oils that are approved for use on this engine.

It may be a coincidence, or it may not be - this is what I stated in my reply in the other thread linked.

Edit: I see what you are saying about "changing" the spec. Yes - it was changed. I was only clarifying that it was changed to add more oils, and that the oils previously allowed have not been changed.

[DLSJ5]

Originally Posted by regular guy

I don't mind having a hypertechnical debate. But if we do that...here's where it goes.

Since none of us work at BMW and have direct access to the information, that means ALL of our opinions are speculation...your above opinion as well.

Yes "it" was changed. The list of allowed oils changed from strictly TWS-10W60 to TWS-10W60 + all LL01 oils.

Agreed, most of us get that.

[BPMSport]

Originally Posted by regular guy

I did not say or imply any such thing. Let's not "speculate" on what I meant...if I did not say it.

Sorry, that's what I took from your comment:

"Pretty clear where I'm sitting that BMW didn't think all was well, and that increasing clearance alone didn't fix whatever they were chasing. The question begs back to BMW: if it ain't broke, why did they try to fix it...twice?"

My apologies if I read this the wrong way.

[DLSJ5]

Originally Posted by Mike Benvo

I quote RG from the other thread
"2) BMW changed spec on oil to 0W40 in August 2013."

There is a difference between CHANGING the spec, and ADDING oils that are approved for use on this engine.

It may be a coincidence, or it may not be - this is what I stated in my reply in the other thread linked.

Fair enough.

[regular guy]

Originally Posted by Mike Benvo

I quote RG from the other thread
"2) BMW changed spec on oil to 0W40 in August 2013."

There is a difference between CHANGING the spec, and ADDING oils that are approved for use on this engine.

It may be a coincidence, or it may not be - this is what I stated in my reply in the other thread linked.

If I had added the word "allow" then you would have no point. Ouch. You got me. Quit sniveling over a single word.

[BPMSport]

Originally Posted by regular guy

If I had added the word "allow" then you would have no point. Ouch. You got me. Quit sniveling over a single word.

I'm not trying to "get you".... There is no reason to be aggressive. I think clarification on this point is important, that's all.

[regular guy]

Originally Posted by Mike Benvo

I'm not trying to "get you".... There is no reason to be aggressive. I think clarification on this point is important, that's all.

I don't see the point in carrying on the same conversation in two different threads by pulling quotes from another thread and bringing it here. If clarification is so important, then you can ask and wait for an answer or send a PM. It's usually impolite to pull comments from one thread and bring them over to another. Most people might consider that an aggressive move; but it doesn't bother me to be honest.

[BPMSport]

Originally Posted by regular guy

I don't see the point in carrying on the same conversation in two different threads by pulling quotes from another thread and bringing it here. If clarification is so important, then you can ask and wait for an answer or send a PM. It's usually impolite to pull comments from one thread and bring them over to another. Most people might consider that an aggressive move; but it doesn't bother me to be honest.

If the other thread is relevant, there should be no issue linking it as it pertains to the same issue, and contains comments you made in reference to the subject at hand. I'm sorry if others may take this as an aggressive move, although I don't understand that to be the case. This is common practice and is a discussion forum. The reference was for informational purposes and not an act of aggression.