Scary rod bearing thread s85

[CSBM5]

Originally Posted by ///M Power-Belgium

Agreed,but without hours of labor and that counts too,actualy a lot ?

It's not that big of a deal to swap a differential. A pretty easy DIY with a lift. Any indy should be able to do the job for you in 2-3 hours, so perhaps figure on $2-300 labor if you're not going to DIY.

[VCMpower]

start a differential thread.

[aussiem3]

Originally Posted by W///

That's a brand new car!
Do you guys in Aussie have a way to get your oil analyzed?

Yes, there is a local company and when I do the oil change in November/December I will send a sample for testing. Would like to see what the outcome is.

[aussiem3]

Originally Posted by kawasaki00

... Furthermore I run the rotella 5-40 and I change it every 4k miles. The cost of the oil allows me to change it more often. I have NEVER had to add oil because the 4k miles or the 6 months always comes up first.
I am not knocking the tws because it really is a superior oil to almost anything on the market today. The big problem is that it is a 10-60. I am by NO means telling people what to run. If others want to run something different more power to them, or those who choose to stick with the tws that is on there own account.

So any 5w-40 would be fine then. I don't care about the consumption and I can always top it up given it will be a lot cheaper than 10w-60.

I am just thinking whether using Liqui Moly 10w-60 Race Tech will help in terms of its oil properties.

I am going to run Castrol Edge 5w-40 for the second half of the year and then 10w-60 for the first half which is lot warmer in our part of Australia. I think running a slightly thinner oil during cold weather and not redlining the car all the time with 5w-40 should to a degree alleviate or prolong the failure. This way some of the lubrication with 5w-40 should remain while 10w-60 is running for 6 months. Some lubrication is better than nothing.

Both Castrol Edge 10w-60 and 5w-40 have the same Titanium Fluid Strength Technology and confirm to the industry standards ACEA A3/B4 and API SN/CF.

http://castroledge.com.au/oils/5w-40-sn

I would like some input from some of you experts.

[BMRLVR]

Originally Posted by kawasaki00

I hate to say it but almost every one of those pictures is not because of a clearance problem. It is a oil starvation problem. The picture of the set that the bottom look good and the top look bad is a big indication of no oil. Also the main bearings that have the cavitation dots at pretty much the same angle across the set is another indicator. There are 2 ways it usually happens. 1 is the 10-60 is too damn thick for a good start up lubrication and 2 at 5-7k rpm there is probably sufficient flow to the oil system. At 8000-8500 the oil pump could be hurting to keep up with flow trying to push a oil that heavy through the system. Remember oil pressure has virtually nothing to do with what we are talking about here, it is all about flow when dealing with rpm. I still firmly believe that a 5-40 oil is the better option for us normal street drivers. If tracking the car and seeing 300 on the oil then the stock oil is probably a better option. Although we run a 5-40 at 10k rpm and 320 on the oil for hours on end with no issues.

In my experience, a bearing with marginal clearance will look almost exactly like oil starvation when it fails! I have seen both tight bearings and restricted oil pump screens resulting in bearings with wear that you wouldn't tell the difference in. In your line of work your clearances are most likely double and triple checked so you wouldn't see many engines with tight clearances?

100% agreement on the 10W60 though too heavy for all but track usage since the oil takes so long to warm up, and sometimes may never warm up depending on the usage of the car!

[e92zero]

Originally Posted by VCMpower

Chances are , if you are doing this correct, your rpm when you go to rev match will not be starting from 850rpm. Oil pressure should already be there. This sound right?

I see. I didn't know it was about the oil pressure vs the free reving the engine.

[kawasaki00]

Originally Posted by aussiem3

So any 5w-40 would be fine then. I don't care about the consumption and I can always top it up given it will be a lot cheaper than 10w-60.

I am just thinking whether using Liqui Moly 10w-60 Race Tech will help in terms of its oil properties.

I am going to run Castrol Edge 5w-40 for the second half of the year and then 10w-60 for the first half which is lot warmer in our part of Australia. I think running a slightly thinner oil during cold weather and not redlining the car all the time with 5w-40 should to a degree alleviate or prolong the failure. This way some of the lubrication with 5w-40 should remain while 10w-60 is running for 6 months. Some lubrication is better than nothing.

Both Castrol Edge 10w-60 and 5w-40 have the same Titanium Fluid Strength Technology and confirm to the industry standards ACEA A3/B4 and API SN/CF.

http://castroledge.com.au/oils/5w-40-sn

I would like some input from some of you experts.

I would be wary of just any ol 5-40, I can run a test on the edge and check the additive package. I choose the rotella because it is still high on zinc and mag numbers. Most other oils have most of that stripped out. I will get a bottle and get back to you.

[VCMpower]

Very nice of you sir.

Originally Posted by kawasaki00

I would be wary of just any ol 5-40, I can run a test on the edge and check the additive package. I choose the rotella because it is still high on zinc and mag numbers. Most other oils have most of that stripped out. I will get a bottle and get back to you.

[aussiem3]

Originally Posted by kawasaki00

I would be wary of just any ol 5-40, I can run a test on the edge and check the additive package. I choose the rotella because it is still high on zinc and mag numbers. Most other oils have most of that stripped out. I will get a bottle and get back to you.

Thank you very much. We don't have Rotella in Australia. The other option is to add some oil additives from Liqui Moly and improve the properties in 5w-40. Just a thought? You're a god send to this forum and topic. Cheers.

[BMRLVR]

Originally Posted by kawasaki00

I would be wary of just any ol 5-40, I can run a test on the edge and check the additive package. I choose the rotella because it is still high on zinc and mag numbers. Most other oils have most of that stripped out. I will get a bottle and get back to you.

+1 Most current oils have the traditional anti-wear additives removed due to their detremental effects on catalysts.

[Longwong]

I have never burned an ounce in 50k miles so what does that mean if it is supposed to happen to these engines?

Also could bmw really have overlooked something like this or are we all focusing on very very few failures that likely are secondary to both random bad luck and maybe some other contributing factors that we do not know about on a case by case basis?

Seems given this engine started in the m5 and then the m3 they would know how to provide proper clearance for bearings. I mean this can't have been overlooked?

[regular guy]

Originally Posted by kawasaki00

I hate to say it but almost every one of those pictures is not because of a clearance problem.

I realize you were responding to Obioban. But I'm curious what your opinion is regarding the bearing samples I showed. My methods were rather simple: I looked at the bearing pictures I found posted, and tried to match them best I could to the Mahle-Clevite bearing failure examples. I have some other S65 bearing samples that match the "wiped" pathologies in the bearing failure page (example #16 in the failure page). I didn't post those pictures however.

Originally Posted by Longwong

Also could bmw really have overlooked something like this or are we all focusing on very very few failures that likely are secondary to both random bad luck and maybe some other contributing factors that we do not know about on a case by case basis?

I think the answer depends on which question you're asking. For the guys whose engines fail for random reasons, I think we're talking very small numbers -- a fraction of one percent. Those are the guys whose bearings and engines failed because of two or more of the clearance issues I listed above. For guys with only one (or zero) of those errors, I would think only the hard-driven track cars, or the guys who go full throttle from cold start should be worried. All we're doing here is trying to put a consistent explanation to the evidence that's available at this time.

If you're building a dedicated track car that will consistently see upper RPM's, you are the guy who needs extra clearance. If you have a supercharged car, you probably shouldn't do anything that will reduce your clearance any smaller than it already is.

I hope this helps.

[BIU]

Originally Posted by regular guy

If you're building a dedicated track car that will consistently see upper RPM's, you are the guy who needs extra clearance. If you have a supercharged car, you probably shouldn't do anything that will reduce your clearance any smaller than it already is.

I hope this helps.

So does this mean we DD guys wont have to worry?

I dont know how this whole thing ties into the infamous cold start-up "clack".. but I do have this issue on and off..

[regular guy]

Originally Posted by mtbkr31

On page 7 (Engine-4: Stock internals, supercharged, Mileage: 72,000), that is my engine. I replaced the bearings with the VAC coated units. Active Auto did all the work and they measured the VAC coated units with OEM stock units...the clearance was the same.

Thanks for contributing to the discussion. It would be nice if your shop could chime in and discuss their procedure for this type of comparison. VCMPower, I believe you said you've done it as well. Could you explain your procedure for doing this comparison? You're an "engine in guy" when you measure, and we're "engine out and disassembled" guys when we measure. Did you use fresh bearings for before/after measurements? Did you use the same connecting rods and measure against the same journal? Did you torque the bolts until yield, or slightly before yield (doesn't matter...just curious). How many did you measure?

[regular guy]

Originally Posted by BIU

So does this mean we DD guys wont have to worry?

That's my opinion; but others might differ. To me, here's the biggest take away from this entire discussion:

1. You have very small clearance already. It's smaller than it probably should be.
2. Don't do anything to make it worse (e.g. coated bearings without adding extra clearance).

To me, it boils down to that simple rule in #2.

I dont know how this whole thing ties into the infamous cold start-up "clack".. but I do have this issue on and off..

I'm not familiar with this issue. Sorry.

[aussiem3]

I found this when I was looking for Rotella in Australia:

http://www.shell.com/rotella/products/tpl-pro.html

[BMRLVR]

Originally Posted by kawasaki00

I hate to say it but almost every one of those pictures is not because of a clearance problem. It is a oil starvation problem. The picture of the set that the bottom look good and the top look bad is a big indication of no oil. Also the main bearings that have the cavitation dots at pretty much the same angle across the set is another indicator. There are 2 ways it usually happens. 1 is the 10-60 is too damn thick for a good start up lubrication and 2 at 5-7k rpm there is probably sufficient flow to the oil system. At 8000-8500 the oil pump could be hurting to keep up with flow trying to push a oil that heavy through the system. Remember oil pressure has virtually nothing to do with what we are talking about here, it is all about flow when dealing with rpm. I still firmly believe that a 5-40 oil is the better option for us normal street drivers. If tracking the car and seeing 300 on the oil then the stock oil is probably a better option. Although we run a 5-40 at 10k rpm and 320 on the oil for hours on end with no issues.

I have to admit that when I first replied to you that I didn't pick up on the fact that you were commenting on Obioban's bearings, I thought you were commenting on regular guy's photos. It wasn't until I read regular guy's reply and looked back that I realized that.

With regards to the S54 bearing photos posted by Obioban I agree that oil starvation may very well have been an issue there. There are definitely many documented S50, S52 & S54 lubrication issues on track driven cars and I think that the engine that those bearings came out of could definitely benefit from a higher volume oil pump and pickup upgrade.

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.

So during my downtime at work tonight I got paid to learn about the S65..... What a great night! I now have a greater understanding of the lubrication system on the S65 and I have even more confidence in adding clearance to the engine and or running a lighter oil since the lubrication system lookes to be more than up to the task. Now if I only had a pump I could flow test and tear down, that would be excellent!!!

[CSBM5]

Nobody has any thoughts/comments/knowledge sparked by my post?

Originally Posted by CSBM5

Is there any online source for actual bearing analysis, at these clearances, for different oil properties? Is what we need to be most concerned with are the HTHS properties of a given oil? If something like a Mobil 1 0-40W has a high enough HTHS rating, one would think it would be a better daily use oil than TWS? If so, what is "high enough" for the clearances and bearing loads experienced in the S65?

Sorry for so many questions...

So here are some more. Looking at the hydrodynamic film in a spinning bearing, as we increase viscosity, we also increase local temperatures in the wedge. I'm curious what the trade-off here is -- where does the increase in local temperatures in the oil wedge result in local reduction in viscosity such that using a less viscous oil achieves the same local viscosity?

And more...

In the old days of dino oils with lots of VII to achieve wide viscosity ranges, I'm aware that these VI improvers, polymers, tend to align under heavy shear like in a bearing, and that alignment results in a significant reduction in viscosity. Once the shear is removed, the viscosity returns to it's stated value. (not bringing up the subject here of viscosity degradation with time due to shearing -- trying to stay focused on the localized, dynamic situation in the bearing oil wedge for the time being). I have some plots of shear rate versus viscosity showing how multi-weight oils (these are old and are for a dino oil) behave in a strongly non-Newtonian fashion whereas a straight weight oil is almost a textbook Newtonian fluid.

So given the above, is that behavior still present in modern day, high quality, synthetic multi-weight oils? If so, is that viscosity degradation under sheer enough to make this a serious consideration at such tight bearing clearances? You can see the semi-worry here -- localized high temperatures resulting in viscosity reduction coupled with very high shear rates reducing viscosity more due to polymer alignment of the multi-weight oil VII.

Disclaimer: I'm not an engine builder (well, if you count two-storke MX bikes back in the 1970s, then yeah, I guess I am, lol), nor engine designer nor tribologist...just an old engineer who ages ago specialized in fluid dynamics and heat transfer but in a different field.

Sorry for the 50 questions, but there appears to be some serious talent on the board here, and I want to learn.

[Longwong]

Just because the pump is up to the task of using lighter oil that does not mean the lighter oil itself is not potentially providing adequate protection at the high rpm speeds of the engine? sure better for bearings but won't it sacrifice other parts of the engine wear?

[VCMpower]

No oil burning here either. Even after doing my motor build. I believe oil consumption is related to break in procedure. You must have done it well

Originally Posted by Longwong

I have never burned an ounce in 50k miles so what does that mean if it is supposed to happen to these engines?

Also could bmw really have overlooked something like this or are we all focusing on very very few failures that likely are secondary to both random bad luck and maybe some other contributing factors that we do not know about on a case by case basis?

Seems given this engine started in the m5 and then the m3 they would know how to provide proper clearance for bearings. I mean this can't have been overlooked?

[VCMpower]

I was a "engine out guy" for my motor and probably would not do the engine in procedure. I do not like working on a motor looking up. Especially this type of torque sensitive work. I used new factory bearings and ARP bolts. I measured with Plasti(I know some think this is romper room), but I have done this for 25+ years. I know how to use it correctly. I have worked in a machine shop and have also ground cranks and resized rods and taken measurements with calipers when going that far, but when I am not changing clearance and am just checking before reassembly, Plasti works well. I used the original rod bolts and did take them to specs when I check clearance. I measured all 8. Mine were .0013-.0015. Hope this helps.

Originally Posted by regular guy

Thanks for contributing to the discussion. It would be nice if your shop could chime in and discuss their procedure for this type of comparison. VCMPower, I believe you said you've done it as well. Could you explain your procedure for doing this comparison? You're an "engine in guy" when you measure, and we're "engine out and disassembled" guys when we measure. Did you use fresh bearings for before/after measurements? Did you use the same connecting rods and measure against the same journal? Did you torque the bolts until yield, or slightly before yield (doesn't matter...just curious). How many did you measure?

[VCMpower]

I am sticking with Fuchs Titan 10w60. I let my car warm up always before going. And it sees redline ALOT!

Originally Posted by Longwong

Just because the pump is up to the task of using lighter oil that does not mean the lighter oil itself is not potentially providing adequate protection at the high rpm speeds of the engine? sure better for bearings but won't it sacrifice other parts of the engine wear?