Official S65 Bearing Specification/Clearance Wiki

[swamp2]

Originally Posted by BMRLVR

Hello All, just wanted to take a few minutes to add this graph of the data that is being collected to help us understand the S65 rod bearings and lubrication system a little better.
...
This graph signifies 30 minutes of engine operation/driving......... And....... There will be a LOT more data to come including track days with both OEM and new Clevite added clearance bearings.

*Oil temp is in degrees C / 10 on the right axis
*Oil pressure is in PSI / 10 on the right axis
*Flow is in GPM on the right axis
*RPM is on the left axis
*Bearings are OEM 702/703
*Oil is Castrol TWS 10w60
*Engine is completely stock with OEM software and stock exhaust

Interesting but somewhat in sync with the overall theme of much data here - more data, less explanation/synthesis/analysis...

rpm and pressure seem very well correlated as expected. However, flow volume and rpm do not exhibit the same sort of correlation. Seems like that may be a red flag of sorts. Then there appears to almost be more significant anomalies in the data. Specifically look at what happens around the 19177 time mark, rpm and pressure are relatively constant (with expected jitter) and flow volume takes a huge and long term nose dive.

Lastly, would be good to know the horizontal axis, it isn't seconds...

[Leonardo629]

I assume when the flow rate (GPM) dips below 2, it means the engine was in cruise mode judging by the less erratic movement of RPM?

[BMRLVR]

Originally Posted by swamp2

Interesting but somewhat in sync with the overall theme of much data here - more data, less explanation/synthesis/analysis...

rpm and pressure seem very well correlated as expected. However, flow volume and rpm do not exhibit the same sort of correlation. Seems like that may be a red flag of sorts. Then there appears to almost be more significant anomalies in the data. Specifically look at what happens around the 19177 time mark, rpm and pressure are relatively constant (with expected jitter) and flow volume takes a huge and long term nose dive.

Lastly, would be good to know the horizontal axis, it isn't seconds...

Just to clarify swamp, this testing is in its infancy since this is the first data that included oil pressure which makes it the first data captured that is of any real use.

The flow volume is not a red flag since pressure is staying consistent, honestly when I got sent the first data files that were devoid of pressure data I thought the same thing. Since the main oil pump in the S65 is a variable displacement vane pump it regulates flow based on the system pressure which means that it strokes back (reduces it's displacement) or strokes up (increases it's displacement) as is necessary to maintain pressure nearly constant. To comment on the flow nose dive, the conditions on the graph show that the pressure stays dead constant through this area and the RPM stays fairly constant too. Something to consider is that the VANOS system requires lots of oil flow which is I think is one of the main reasons for a variable displacement oil pump to be used. When the DME is requesting camshaft adjustment the demand for oil flow is going to increase greatly and hence the pump will be stroked up to maintain a consistent oil pressure for the VANOS system to be able to consistently and accurately adjust the camshafts at the proper rate of adjustment during times of added flow demand. Since the RPM is fairly stable in this area of low pump flow, the VANOS was not requiring much if any oil flow since the cams were not being adjusted during this constant RPM area of operation. The only oil flow required during this part on the graph would be to maintain pressure in the main oil gallery for engine lubrication.

Another plus of using a variable displacement pump is that it is not always sending oil over the relief valve like a fixed displacement pump. Oil going over relief creates unnecessary heat and places unnecessary load on the engine. As long as the pressure is consistent regardless of what type of pump is used, fixed or variable displacement, the oil that is over the pressure setting in the system relief or over the setting in the compensator in the pump is not going to be sent to the main oil gallery in the engine. In a lubrication system with a fixed displacement pump all additional unneeded oil flow is going to go over relief, and in a system with a variable displacement pump the pump will just reduce displacement and hence flow until pressure drops enough to cause the pump to stroke again up and make additional flow when it is needed.

As far as explanation/synthesis/analysis goes, this testing was mainly done to compare the oil flow, pressure, and temperature at given RPM's between the OEM bearings and the Clevite bearings with added clearance. No real testing method was developed and the only intention was to prove that the bearings with the added clearance were still within the OEM specs for oil pressure. With my trade as a heavy equipment technician I maintain, troubleshoot and repair hydraulics and according to my limited knowledge of the S65 lubrication system it appears this one is operating properly and according to the principles in any basic hydraulic system. In fact I am impressed how consistent the pressures stay without any accumulator in the system, they really have the pump compensator dialled in very precisely. On the average system I see, the cut in an cut out pressure of the pump will be separated by 500-600 psi on a ~3500PSI operating pressure running an accumulator to smooth out pressure peaks and valleys and provide for emergency flow for steering and brakes in the event of a system or engine failure.

To comment on the x-axis, it is the number of samples at 10HZ sampling rate. I was wrong in telling you that this graph covers 30 minutes of engine operation, it is indeed 50 minutes. 30000 samples /10 = 3000 seconds. 50 minutes x 60 seconds = 3000 seconds.

Please feel free to critique and or add to this conversation if you feel that there is anything that we are missing or that we should be doing.

Originally Posted by Leonardo629

I assume when the flow rate (GPM) dips below 2, it means the engine was in cruise mode judging by the less erratic movement of RPM?

That is correct.

[swamp2]

Originally Posted by BMRLVR

The flow volume is not a red flag since pressure is staying consistent, honestly when I got sent the first data files that were devoid of pressure data I thought the same thing. Since the main oil pump in the S65 is a variable displacement vane pump it regulates flow based on the system pressure which means that it strokes back (reduces it's displacement) or strokes up (increases it's displacement) as is necessary to maintain pressure nearly constant.
...
To comment on the x-axis, it is the number of samples at 10HZ sampling rate. I was wrong in telling you that this graph covers 30 minutes of engine operation, it is indeed 50 minutes. 30000 samples /10 = 3000 seconds. 50 minutes x 60 seconds = 3000 seconds.

There we go, that is the analysis/synthesis I was hoping to hear. Excellent. I suspected that the variable displacement pump was likely the key to better understanding the graph.

[BMRLVR]

Originally Posted by swamp2

There we go, that is the analysis/synthesis I was hoping to hear. Excellent. I suspected that the variable displacement pump was likely the key to better understanding the graph.

By the way, here is a picture of the flow meter that is being used to get oil flow data on the S65.

[Grk_M3]

Greetings guys.

So much nice and interesting facts in this post. Being a recent victim too of the rod bearing curse, there is plenty here to help me with my engine rebuild. I was fortunate enough not to blow a rod out the case, unfortunate tho as the metal filings hit the oil pump, and also scared some of my cylinders.

I am trying to contact Regular guy, anyone know how I can get a hold of him, please pm any details as he cant receive pm.

Thanks in advance!

[theboss1853]

Originally Posted by Grk_M3

Greetings guys.

So much nice and interesting facts in this post. Being a recent victim too of the rod bearing curse, there is plenty here to help me with my engine rebuild. I was fortunate enough not to blow a rod out the case, unfortunate tho as the metal filings hit the oil pump, and also scared some of my cylinders.

I am trying to contact Regular guy, anyone know how I can get a hold of him, please pm any details as he cant receive pm.

Thanks in advance!

First my condolences.. sorry this happened to you. I just got my car back after many months of rebuilding it. What's the manufacture date of your S65? Did you hear the "ticking" noise a low RPMs? How fast were you going and what RPMs when the bearing spun? How many miles on the engine? I can help out for sure as I worked closely with RG on my rebuild and have all the info and the parts list if you plan to rebuild. Hope you have a good mechanic...

[atruelunatic]

Originally Posted by Grk_M3

Greetings guys.

So much nice and interesting facts in this post. Being a recent victim too of the rod bearing curse, there is plenty here to help me with my engine rebuild. I was fortunate enough not to blow a rod out the case, unfortunate tho as the metal filings hit the oil pump, and also scared some of my cylinders.

I am trying to contact Regular guy, anyone know how I can get a hold of him, please pm any details as he cant receive pm.

Thanks in advance!

regular guy

Hopefully this'll help him see you! (assuming the tag works)

[Bx Tpr]

Good stuff and thanks to everyone involved for all the work. There is some real good info on this thread.

[Green-Eggs]

The BMW 702/703 bearings are made by Glyco, not King. If you can't see the logo in this picture, click on it for a closer look.



That's the same logo found here:


But here's the interesting part. This bearing is made from the Glyco Bimetal Aluminum. Here's what the Glyco catalog says about it:

Provides greater seizure resistance and surface hardness than tri-metal materials, while dramatically reducing or eliminating bearing wear in a wide range of automotive and truck engines. Bored inside diameters improve the bearing’s oil retention utilizing hundreds of micro-grooves to provide channels in which debris is flushed away.

So that confirms the measurements in this wiki that these bearings are indeed much harder than the original 088/089 bearings, and explains why we see those little grooves in the pictures of people who replace these bearings.

But here's the sad part. There are six different Glyco bearing compositions, from best to worst. This Bimetal Aluminum bearing is fourth in the pecking order. That tells me it might not be a very high quality part and may have been chosen for cost savings. The next one up their quality list is the Trimetal lead/copper bearing. YMMV

[G80indy]

You didn't include all the relevant info :

"The Future is Aluminum--
Overplated copper-lead (?tri-metal?) has been the dominant engine bearing material for the past 20 years. But no longer. Over time, major domestic and overseas engine manufacturers have virtually eliminated it from their designs. And in the aftermarket, leading engine builders are phasing it out as well. The reason! A new breakthrough in engine bearing technology. Sealed Power A-Series engine bearings with aluminum-silicon bi-metal alloy. A-Series? bi-metal alloy delivers greater seizure resistance than tri-metal materials, while dramatically reducing or eliminating bearing wear in a wide range of automotive and truck engines. The increased wear resistance is due in large part to the use of silicon, which produces significantly greater surface hardness. The silicon particles also help polish the crank surface during engine operation, further reducing friction and related wear. An additional benefit of A-Series bearings is their precise bearing wall size control. Because these bearings are unplated, manufactured wall variances can be reduced by as much as 40 percent. This improves oil clearance tolerances ? and in fact makes it possible to maintain OEM clearances over the life of the engine ? thereby reducing operating noise, vibration and harshness. Sealed Power A-Series bearings feature bored, rather than ?broached?, ID?s. Boring is a more exacting process and one that improves the bearing?s oil retention, seizure resistance and fatigue strength. Most OEMs now specify aluminum bearings that are bored, and this technology is expected to become the dominant choice of engine builders in the near future. Rather than embedding debris where it can remain and cause damage, A-Series bearings utilize hundreds of oil filled micro-grooves to provide channels in which debris is flushed away and later caught by the oil filter. Potentially damaging particles never have a chance to score the crankshaft."

[OM VT3]

Originally Posted by 330indy

You didn't include all the relevant info :

"The Future is Aluminum--
Overplated copper-lead (?tri-metal?) has been the dominant engine bearing material for the past 20 years. But no longer. Over time, major domestic and overseas engine manufacturers have virtually eliminated it from their designs. And in the aftermarket, leading engine builders are phasing it out as well. The reason! A new breakthrough in engine bearing technology. Sealed Power A-Series engine bearings with aluminum-silicon bi-metal alloy. A-Series? bi-metal alloy delivers greater seizure resistance than tri-metal materials, while dramatically reducing or eliminating bearing wear in a wide range of automotive and truck engines. The increased wear resistance is due in large part to the use of silicon, which produces significantly greater surface hardness. The silicon particles also help polish the crank surface during engine operation, further reducing friction and related wear. An additional benefit of A-Series bearings is their precise bearing wall size control. Because these bearings are unplated, manufactured wall variances can be reduced by as much as 40 percent. This improves oil clearance tolerances ? and in fact makes it possible to maintain OEM clearances over the life of the engine ? thereby reducing operating noise, vibration and harshness. Sealed Power A-Series bearings feature bored, rather than ?broached?, ID?s. Boring is a more exacting process and one that improves the bearing?s oil retention, seizure resistance and fatigue strength. Most OEMs now specify aluminum bearings that are bored, and this technology is expected to become the dominant choice of engine builders in the near future. Rather than embedding debris where it can remain and cause damage, A-Series bearings utilize hundreds of oil filled micro-grooves to provide channels in which debris is flushed away and later caught by the oil filter. Potentially damaging particles never have a chance to score the crankshaft."

Only because in europe they cant use lead anymore not because its better

[pbonsalb]

I wonder whether wpc treatment, which many of us have had done on the newer bearings, closes up all those miscroscopic bores designed to channel away debris that could otherwise scratch journals.

[admranger]

Originally Posted by pbonsalb

I wonder whether wpc treatment, which many of us have had done on the newer bearings, closes up all those miscroscopic bores designed to channel away debris that could otherwise scratch journals.

I'd bet money it does.

[aus]

Originally Posted by Grk_M3

Greetings guys.

So much nice and interesting facts in this post. Being a recent victim too of the rod bearing curse, there is plenty here to help me with my engine rebuild. I was fortunate enough not to blow a rod out the case, unfortunate tho as the metal filings hit the oil pump, and also scared some of my cylinders.

I am trying to contact Regular guy, anyone know how I can get a hold of him, please pm any details as he cant receive pm.

Thanks in advance!

Sorry to hear that.
Unfortuately, I added you to the registry.

[BMRLVR]

Hello All, thought I'd post a photo of some bearings that I thought would be relevant to the conversation here.

The background to how this came about is that I started getting an oil pressure light at idle on my 1994 E36 Sedan (S50B30 Euro engine). I changed the pressure switch but the light still stayed on so I got some fittings, a gauge and made up a hose at work and gauged the pressure. Once I had the gauge on the car it came clear what the issue was, the relief valve in the oil pump was stuck partially open and I had next to no oil pressure at idle (2-3 psi at idle even on a cold start) but lots of oil pressure as the revs built (over 100 psi and climbing by 5000 RPM).

Once I finished troubleshooting I ordered a modified oil pump from VAC with the upgraded keyed shaft to prevent the E36 oil pump nut and shaft shearing issues and proceeded to disassemble the car. Part ways through the disassembly I decided since I would probably never drop the subframe and oil pan on this car again I should do the rod bearings. I ordered bearings and bolts and waited for all the parts to show up.

Anyway, the engine is all back together and oil pressure is now within OEM specs so here are the bearings. The engine has 94,000 (151,000KM) original miles on the original bearings (date stamp of 04/94).









One interesting thing to note is that the clearance specs on TIS for the S50B30 are 0.001 - 0.003" (0.028 - 0.070mm) which would put the nominal clearance right at 0.002" (0.050mm). Redline is 7280 and oil weights come from a wide variety of grades in the Xw30 - Xw40. Based on the 50mm rod journal diameter the nominal clearance of 0.002" (0.050mm) would put this engine right at the 0.001"/ inch of journal diameter that many of us have been quoting as best practice for a while now.

Any how, back when BMW was building these engines rod bearings were not known as a big issue and strangely enough they were building engines with tolerances much more in line with what many of us would like to see and right in line with what the new BE bearings are giving us for clearance .

[pbonsalb]

Interesting BMW specs show 0.001 is acceptable.

[BMRLVR]

Originally Posted by pbonsalb

Interesting BMW specs show 0.001 is acceptable.

There has to be a range and when there is a range like that the target is usually right in the middle.

The thing that makes the 0.001" lower side of spec not so crazy is the fact that BMW specs 30 and 40 weight oils for use in this engine, not a 60.

[pbonsalb]

Originally Posted by admranger

I'd bet money it does.

WPC says no issues with micro groove bearings.

[admranger]

Originally Posted by pbonsalb

WPC says no issues with micro groove bearings.

As soon as I see photos that show that, I'll believe it. I don't see how you can make the surface look like WPC does and leave the grooves. I'm not saying I'm right (or that you're wrong), I'm saying I need some proof other than WPC guys saying everything's ok.

[Demon Barber]

Is there a general consensus whether or not Blackstone oil analysis is a reliable indicator of bearing wear for those with lead bearings and those with newer bearings? Has anyone verified accelerated bearing wear with the newer factory aluminum 702/703 bearings and had any indication on their oil analysis that it was occurring? I'm trying to figure out if a bearing replacement would be wise or unsubstantiated at this point.

[Obioban]

Originally Posted by admranger

As soon as I see photos that show that, I'll believe it. I don't see how you can make the surface look like WPC does and leave the grooves. I'm not saying I'm right (or that you're wrong), I'm saying I need some proof other than WPC guys saying everything's ok.

My impression is that the WPC treatment is effectively a nano scale shot peening process. If that is correct, I see no reason they couldn't perform nano scale shot peening on micro scale bearing grooves.