-- Better Bearings for your BMW

BMW Bearings Calico, VAC, WPC BE Bearing Design Buy BE Bearings Contact Us
Explains engine failures Previous attempts and stopgap measures Our bearings aren't a stopgap, they're a fix Custom bearing selection and purchasing details Who are we and what do we do here?

Take aways of this article:

Table of Contents


Factory bearing primer

The original 088/089 BMW factory bearings were made by Clevite as a "Tri-Metal" design.  Tri-Metal is a three metal process.  The base steel layer, topped with copper, topped with lead.  These are a very soft bearing and good for your crankshaft.  The lead is soft and can absorb small foreign particles without damaging the crankshaft.  The original factory bearings may not be of sufficient clearance, but they are a great design (no design flaw).  In addition to being very maleable and soft on the crankshaft, the lead-copper bearings provide great early warnings of engine failure through Blackstone oil analysis.  Having your oil analyzed regularly, one experiencing excessive wear would see elevated lead and copper in the oil analysis.

But the European Union (EU) mandated that all vehicles, except those already in production, and made 2011 or later, must remove the lead from the bearing material.  Even though BMW had the choice to keep the 088/089 Clevite lead-copper bearings, they chose to make a new bearing.  The new bearing manufacturer is a bit unknown, but it's believed to be "King" Bearings out of Israel.

The new 702/703 bearing has about the same clearance as the older 088/089 Clevite bearing, but instead of being made of lead-copper, it is made out of tin-aluminum.  The tin-aluminum is much harder at the surface, and much harder on the crankshaft.  It is this extra hardless that is believed to contribute to increased engine failures on these engines with 702/703 bearings.  In addition to extra hardness, early bearing wear is much more difficult to detect with a Blackstone oil analysis (due to lack of lead and copper).

S65/S85 Bearing Hardness Issues:

What has been observed is the original 088/089 bearings are a copper/lead content while the 702/703 bearings are of an aluminized tin/silicon compound.  Measurements with my mic are as follows and the clearance for the final outcome.
BMW Part Number Thickness Hardness
088 0.07875 16.2 B Scale
089 0.07885 16.2 B Scale
091 0.08370 16.2 B Scale
090 0.08360 16.2 B Scale
702 0.07855 61.8 B Scale
703 0.07875 61.8 B Scale

These measurements align with what other people have measured as well. What is a MASSIVE change is the hardness of the bearings. The new 702/703 bearings are a huge jump in hardness:

The new 702/703 tin-aluminum bearings are nearly 4-times harder than the previous Clevite 088/089 lead-copper bearings.
















VAC/Calico Coated Bearings (See Update*)


One popular solution was the use of the VAC/Calico coated bearings. Many engine builders frown upon the use of coated bearings because they add to the bearing thickness, and the coating wears quickly and unevenly. The Calico web site specifies the added thickness between 0.00020 - 0.00040 inch. For the S65 with a potential bearing clearance issue, this could be the wrong approach. On the flip side, hot rodders love them because they decrease the bearing surface friction. But until now, no data was available to know one way or the other.

On my recent data gathering trip, Tom @ EAS was gracious enough to allow me to measure some VAC/Calico coated bearings he was installing on their shop/track car. I didn't measure all of the bearings; I only measured two. I also didn't have a chance to a proper clearance test on these bearings.. However I did measure the bearing thickness and compared it to a reference sample of factory bearing. Using the factory bearing as reference, it's easy to see whether or not the bearings are thicker, thinner, or relatively the same as factory. These are my measurements exactly as I wrote them down.

Factory Reference
VAC-1
VAC-2
Top (Blue)
0.07885
0.07880
0.07885
Bottom (Red)
0.07865
0.07890
0.07895


First thing to notice are the VAC Uppers are thinner than VAC Lowers. It looks very clearly like the bearing shells are reversed becaused the uppers are supposed to be thicker than the lowers. But in these sample measurements, the lowers were thicker than the uppers. This is why I concluded the bearings were mislabled. In the chart below, I corrected the measurements to correctly correspond with the BMW upper and lower bearing shells.

Factory Reference
VAC-1
VAC-2
Top (Blue)
0.07885
0.07890
0.07895
Bottom (Red)
0.07865
0.07880
0.07885


Next thing to notice are the bearings are indeed thicker than factory bearings. Using these two examples, the extra thickness ranges between 0.00020 - 0.00030 inch, exactly where Calico specifications say they should be. Even though I didn't have a chance to place these bearings into a connecting rod and measure the clearance, using these measurements above, it's fairly clear to see how the clearance would be affected. I know this isn't a scientific test as the measurements are a mere approximation. Once actual measurements become available, the data below will be replaced with actual clearance measurements.

Best Case FCT+VAC
Worst Case FCT+VAC
Best Case CARR+VAC
Worst Case CARR+VAC
Crank Journal
2.04650
2.04660
2.04650
2.04660
Rod Bore
2.04815
2.04750
2.04760
2.04745
Bearing Clearance
0.00165
0.00090
0.00110
0.00085


Before leaving, I was able to talk to Tom and Steve at EAS. I told them my findings. At first I thought the bearings were relatively unchanged versus factory. But after closer inspection, I could clearly see they were approximately 0.00010 - 0.00015 thicker than stock. Add the two half bearings shells together and you get the exact Calico specification of 0.00020 - 0.00040 thickness of their coating. I also alerted Tom and Steve to what I believed were the mislabeled bearing shells: uppers marked as lowers, and visa versa. Therefore as one final test, we put one of the VAC/Calico bearings into a factory connecting rod I brought with me. We measured 0.00290 inch clearance, which is far larger than anything I measured before; in fact it's too large. I'm still perplexed by this result, but it may have been because we didn't have time to remove the coating from the parting lines on the bearing shells -- which I'm told will invalidate the results. So until I get a full set of VAC/Calico bearings to measure, the full set of VAC results are somewhat inconclusive.

Thanks to Tom and Steve @ EAS for letting me take these measurements and share them with the community.

Comparison between Virgin 702/703 bearings and Calico Coated bearings

702/703 Results
R1
R2
R3
R4
R5
R6
R7
R8
MIN
Max
Official
Min Dev.
Max Dev.
Top (Blue)
0.07870
0.07870
0.07865
0.07865
0.07865
0.07865
0.07865
0.07865
0.07865
0.07870
0.07870
-0.00005
0.00000
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
Calico Results
R1
R2
R3
R4
R5
R6
R7
R8
MIN
Max
Official
Min Dev.
Max Dev.
Top 0.07850 0.07860 0.07855 0.07850 0.07860 0.07860 0.07850 0.07855
0.07850
0.07860
0.07860
-0.00010
0.00000
Bottom 0.07870 0.07875 0.07885 0.07875 0.07870 0.07875 0.07885 0.07885
0.07870
0.07885
0.07880
-0.00010
0.00005


Notes:

Conclusions:

This was a stopgap measure to add a non-friction coating to the bearings.  It was well intended, but poorly executed.  Simply said: it was the wrong solution for the problem.  Instead of increasing clearance, this reduced it.  Recommendation to stay away from this approach.

Update*

These bearing measurements are the first measurements made during the "m3post bearing wiki" investigation and discovery phase.  Updated measurements and the most latest specifications are available at the BE Bearings wiki pages.
http://wiki.rcollins.org/core/index.php/Engine_Specs_-_S65_Rod_Bearings#Bearing_Clearance_Specifications_6

 

WPC Treated Bearings (See Update*)


Pictures show factory bearings (left) compared to WPC treated bearings (right).

Here's a very popular stopgap solution that was introduced by Auto Talent in Los Angeles.  WPC has a micro shot peening process that they say reduces friction without changing dimensions of the treated surface. WPC uses this treatment on many surfaces including engine bearings. It's hard to imagine engine bearing thickness wouldn't be affected by the WPC treatment because we're looking at clearances in the ten-thousandths of an inch. M3post user E92Zero proposed to send my reference bearings to WPC for treatment then let me take proper measurements when they returned. But as pure luck would have it, Auto Talent had already sent out a complete set of bearings for the WPC treatment and they arrived while I was in the area collecting all of the data for this article.

While on my way to EAS to measure the VAC coated bearings, Auto Talent was gracious enough to allow to measure two sets of bearing shells (two uppers, two lowers). I documented and photographed the results as follows: 

Factory Reference
WPC-1
WPC-2
Top (Blue)
0.07885
0.07875
0.07870
Bottom (Red)
0.07865
0.07860
0.07850


Just as I had hoped, the bearings were thinner than stock. After collecting the measurements, Auto Talent allowed me to take the same two specimens to Van Dyne Engineering for our much more thorough bearing measurement tests. While at Van Dyne Engineering, we put the WPC coated bearings in our factory connecting rods to obtain proper clearance measurements. I torqued the WPC treated bearings into two factory connecting rods to obtain the data listed below.

WPC-1
WPC-2
Crank Journal
2.04655
2.04660
Rod Bore
2.04825
2.04820
Bearing Clearance
0.00170
0.00160

Conclusions

This became a very popular stopgap measure.  Until custom bearings could be made, this was the #1 solution provided to S65/S85 owners.  As a stopgap, it was pretty good.  But at the end of the day, it was still a stopgap and not a solution.

Update*

These bearing measurements are the first measurements made during the "m3post bearing wiki" investigation and discovery phase.  Updated measurements and the most latest specifications are available at the BE Bearings wiki pages.
http://wiki.rcollins.org/core/index.php/Engine_Specs_-_S65_Rod_Bearings#Bearing_Clearance_Specifications_5

VAC Clevite Coated Bearings (See Update*)

Background

Early 2015, m3post member "Malloy" gave us all a tip that VAC had custom made bearings from Clevite. Back in post #2421 of this thread, I got to the bottom of this and discovered that VAC and Clevite had indeed made some custom S65/S85 rod bearings. I purchased a set, had them shipped overnight, Saturday delivery so I could measure them over the weekend.

There was just two problems with what I was trying to do: 1) I had loaned out all of my virgin rod bolts, and 2) I had shipped out and sold my OEM connecting rods. Getting rod bolts on the weekend was tough (real tough when you hear what I mean). I found a full set down in Monterey, California, on the coast, at the beach, only a few miles from Laguna Seca Raceway. It was a very tough ride, all 45 miles of it, sun beating down and beautiful at 85 degrees. I had also arranged to borrow a set of OEM connecting rods over the weekend. These came from a local shop, straight out of the box, OEM remanufactured connecting rods from BMW. It looks like the remanufactured rods were re-honed, and the rod bolt surface was remachined. These rods had bolts in them, and were untorqued when they arrived.

VAC-Clevite bearings

Right before leaving for that difficult ride to the beach, the VAC-Clevite bearings had arrived. I opened them immediately and discovered they were indeed custom made bearings.








VAC had given me preliminary specifications during my phone call the week prior. This is what they said.
Engine guy calls me back a few minutes later and says it's true...they did contract with Clevite to make some custom rod bearings. The new bearings, as he explained, were designed with 0.0005 inch extra clearance. VAC still adds the Calico coating, which he acknowledged takes up the extra 0.0005 inch -- returning the new bearings back to stock clearance.

So the bearings start life with 0.0005 inch extra clearance, have Calico coating added (which reduces by 0.0005 inch), and you end up with factory rod bearing clearance again.

Now it's time to put that to the test. But first, there's one more thing I need to do.

The Calico coated bearings don't mask off the material from the parting lines, so they must be removed before using. Failure to do this could result in improper bearing crush, which also translates to improper clearance and eccentricity. I'm not sure how many people know this, or do this, which is one reason I'm critical of Calico Coatings in the first place.

It's a simple process. I used 800 grit wet-dry sandpaper and swiped the bearings back and fourth 4 to 6 times in each direction.







Removing the material from the parting lines is a simple, easy, but an essential process. Once it's finished, the bearings should look like this:







Preparing to Measure

Preparing to measure always takes some time. With the new rod bolts, I had to pre-stretch them according to BMW specifications. Once stretched, they're ready to measure.

I also wanted to measure the new bearing eccentricity, so I came up with this nice little diagram to help locate the places I wanted to measure.



Next, it's time to calibrate the instruments, then time to measure.



Measuring Eccentricity

Eccentricity
5 degrees
19.75 degrees
45 degrees
90 degrees
175 degrees
161.25 degrees
135 degrees

 

Measuring Virgin 702/703 Bearings for a Baseline

Kawasaki00 recommended that I also measure the virgin 702/703 bearings as a baseline. He appealed to the perfectionist side of me and didn't even need to convince me to do it. I knew it had to be done; and I'm glad I did.

This would be the first time that virgin bearings, virgin rod bolts were placed in virgin rods (remanufactured by BMW) and measured. This baseline was too important to ignore. So I swapped bearings, and re-measured all over again.

Virgin 702/703's
Rod-1
Rod-2
Rod-3
Rod-4
Rod-5
Rod-6
Rod-7
Rod-8

The Results

The results were very conclusive. The baseline measurements on virgin 702/703 bearings, using virgin rod bolts, and virgin (remanufactured) connecting rods showed a perfectly consistent 0.00150 inch clearance. This sets a new baseline for 702/703 bearings. The original baseline measurements used a single crankshaft, and gave a nominal clearance specification of 0.00165 inch. At the time, this was a 0.00020 inch clearance increase over the original 088/089 lead/copper bearings. When the 96 crankshaft journals were rolled up into the measurements, the nominal clearance increased to 0.00170 inch. Now with the addition of these new measurements being rolled up, and the fact that all eight of them were indistinguishable the new baseline for 702/703 bearings goes back down to 0.00150 inch clearance, making it virtually indistinguishable from BMW's original 088/089 bearing clearances we've measured.

With the new baseline established, we can now compare the VAC-Calico custom bearings to see the difference. The original VAC salesman said the new bearings would increase 0.00050 inch before the coating and would equal the same BMW clearance after the Calico coating. The measurements show instead of maintaining stock clearance after the coating, the actually increase the stock clearance by exactly 0.00050 inch after the coating.

Here's the table of measurements.

Virgin 702/703's
Rod-1
Rod-2
Rod-3
Rod-4
Rod-5
Rod-6
Rod-7
Rod-8
Min
Max
Official
Min Dev.
Max Dev.
Rod B.E. Bore
2.20610
2.20600
2.20575
2.20580
2.20580
2.20590
2.20580
2.20570
Rod Journal Diameter
2.04650
2.04650
2.04650
2.04650
2.04650
2.04650
2.04650
2.04650
702/703 Bearings
2.04800
2.04795
2.04800
2.04800
2.04805
2.04800
2.04800
2.04800
702/703 Clearance
0.00150
0.00145
0.00150
0.00150
0.00155
0.00150
0.00150
0.00150
0.00115
0.00200
0.00150
-0.00035
0.00050
VAC-Clevite Clearance
0.00210
0.00190
0.00190
0.00210
0.00210
0.00190
0.00210
0.00210
0.00190
0.00210
0.00200
-0.00010
0.00010
VAC-Clevite Bearings
2.04860
2.04840
2.04840
2.04860
2.04860
2.04840
2.04860
2.04860
Rod Journal Diameter
2.04650
2.04650
2.04650
2.04650
2.04650
2.04650
2.04650
2.04650
Bearing Thickness Top
0.07840
0.07840
0.07840
0.07835
0.07835
0.07835
0.07830
0.07825
0.07825
0.07840
0.07835
-0.00010
0.00005
Bearing Thickness Bottom
0.07840
0.07840
0.07835
0.07835
0.07835
0.07835
0.07830
0.07825

Bearing Eccentricity

Bearing eccentricity may also be of interest. The VAC-Clevite bearings use the same bearing eccentricity as the original BMW (Clevite) 088/089 bearings. The graph clearly shows this distinction.



Conclusions:

The new baseline for 702/703 bearings show the clearance is about the same as the original 088/089 BMW bearings. Folks who have been banking on this 0.00020 inch increase for their arguments in the bearing threads will need to adjust to this new reality.

The VAC-Clevite bearings show an extra 0.00050 inch clearance over stock. The new bearings are a Clevite Tri-Metal construction using lead-copper composition. The lead-copper composition is highly advised for Blackstone oil tracking because it allows to track lead as an indirect indication of bearing wear and life.

The new VAC-Clevite bearings are a good option for factory clearances.  I would prefer these over OEM bearings.  But they don't increase the clearance to the point the S65/S85 needs to be.  These bearings are good, but they're not good enough.  A new bearing, BE-Bearings are needed to fix the problem.


Photo journal with additional pictures is available here:
http://rcollins-home.org/photobucket....php?album=235

Update*

These bearing measurements are the first measurements made during the "m3post bearing wiki" investigation and discovery phase.  Updated measurements and the most latest specifications are available at the BE Bearings wiki pages.
http://wiki.rcollins.org/core/index.php/Engine_Specs_-_S65_Rod_Bearings#Bearing_Clearance_Specifications_4

Proposed Solutions: Thinner Oil

I'll be first to tell you that I'm not an oil expert, but I'm very impressed with the information that kawasaki00 and BMRLVR have contributed to this discussion. I'll try to collect some of their best posts and weave it into a cohesive discussion.
I am looking at the Rotella T6 for my car on the next oil change. The T6 must be a stout oil since it has the JASO MA rating on the back...... Not many passenger car/ diesel engine oils meet motorcycle certifications which is a testament to the base stock it is blended from. Motorcycles throw a whole different curve at oils since they have to deal with lubricating a transmission and a wet clutch as well as an engine that can spin upwards of 15000RPM......... But judging by your username I don't need to tell you anything about motorcycles! -- BMRLVR
You are correct on the rotella in the motorcycles, along with my full-time job I also raced a zx-10r for a couple years. There have been some complaints over the last year or so about the t6 though, some of the high power bikes are having a touch of clutch chatter. The zinc and phosphorous levels have dropped from 1600 to about 13-1400 in the new t6. For engine bearings, flat tappet cams and the like that number is still plenty high. The tws oil is about 16-1700 on zinc numbers. BUT although it is higher that doesn't mean it is superior. Mobil 1 racing 4t is being sold as a motorcycle oil but it is really a normal engine oil with about 1500ppm of zinc and phosphorous. The problem is that it is a 10-30 so not really picking up much as far as our clearance problem. -- kawasaki00
Ok, then someone edumacate me. 10w-60 means SAE viscosity of "10" when cold, right? and "60" when at temp, right? soooo, what am I doing wrong here? -- Transfer
http://www.upmpg.com/tech_articles/motoroil_viscosity/

This explains it. 
For this problem we have if there were a 5w-60 that would be the ultimate for us. Unfortunately there is no such grade. The 5w would help a ton at start up but still protect like a 60 weight at temp. This is why the rotella 5-40 is a trade off. It is better at low temps and flows better but the untimate high temp shear strength is not as much as a 60.
The second number is the protection factor not the weight. A 10w-30 and a 10w 60 is till the same weight at cold temp. -- kawasaki00
According to the lubrication system schematic for the S65 on BMW TIS it appears as though the engine uses a pressure compensated variable displacement main oil pump. (There is a signal passage off of the main oil gallery in the schematic which is shown as a dotted line...... In my industry, heavy equipment, dotted lines almost always symbolize signal oil in hydraulic schematics). The fact that the pump is variable flow (variable displacement) it would lead me to believe that pump volume should not be an issue in the S65. Variable displacement pumps are used to ensure that max pump volume is available regardless of engine speed. To me this is great news for any of us looking to run additional clearance or lighter oil. This also helps to explain why VCM power claims that the pressure stays constant from 2000RPM on up to redline........ with a pressure compensated pump pressure can remain nearly constant and the system will never have to go over relief except in the event of a system malfunction. -- BMRLVR
The 0w50 is a fantastic oil. The reason I dont bring it up is you need to be catless and be prepared to replace o2 sensors much quicker than normal. Although for most if the car has a supercharger on it they are not worried about a couple hundred bucks for sensors.

Why does the 0w 50 oil cause 02 sensors to go?

Because the 0w-50 that he is talking about is a racing only oil. It has over twice the zinc around 1850ppm I believe. That much zinc will burn coverters up and leave deposits on o2 sensors that skew the data. Kind of like running leaded fuel, but it just doesnt happen as fast. -- kawasaki00