BE Bearings In-Depth: Oil Flow, Oil Pressure Analysis

[Leonardo629]

Thanks for the input

[AutoTalent]

December 2016 update: Archived at BE Bearings wiki page by clicking the following link.

• 2016-12-31

[AutoTalent]

Here's the easiest way to read the December 2016 update.

• See the post immediately above, or post #2.
• Search for "Trend 2016-12"
• All graphs are updated with new data
• If you want to see the older updates or historical data, click any of the "Previous Snapshot" links.

Statistical median and mode data is now available for download from the main wiki page. See links in post #1 or click below.
http://wiki.rcollins.org/core/index...._Flow_Analysis

The data file formats are also described at the main wiki page.

[Green-Eggs]

Originally Posted by Leonardo629

Let me ask again, possible 0w40 testing? It will add a lot of insight to why BMW chose 10w60.

It's a long shot. The oil flow sensor is temperature and viscosity calibrated to the specific oil in use. Extra calibrations cost extra. I think we bought three calibrations, but not sure what they were. Regardless, this already takes up a huge amount of time, and not sure we're willing to go for round #3.

[Wazza]

My brain hurts, anyway ordered the bearings and bolts and should have them installed in the next 6 weeks.

[SDPLV]

Please speaka da English.

[kawasaki00]

This is the only graph we need to pay attention to.
Rod bearings will not live over 7500rpm with under 4 gpm. We have tested it raced it and failed it over and over. That big spike at 7600 is where the cavitaion occurs in teh rod bearings. The oil itself detonates and creates tiny explosions. When that happens air bubbles and pockets scatter out across the face of the bearing and journal. The flow goes way up right after that becuase it is trying to refill that air void.
When going to the bigger clearance the graph shows a much more standard of oil flow for a engine that spins over 8k rpm. Flow should always rise as rpms do.
In a perfect world I would like to see about 80psi at 8k but the increase in flow far outweighs and offsets the 4psi drop in pressure. The pressure drop would only matter if the flow didnt increase such as just taking oil pressure out of it (although not easily feasable)
The pressure graph shows that the pump is EASILY keeping up with demand. Once the pump is being taxed the pressure graph will have a much more linear line from low to high. You only need 10psi per 1k rpm. That has been a rule for i dont know 60yrs. and it still hold true today, being that we are at full pressure down around 3k the pump still has tons of reserve. There is nothing wrong with more pressure down low other than you are wasting efficiency and it drags the engine down ALOT at those lower revs. That being said though it just adds life to the engine by never running out of oil supply.

I am not going to argue with people on here about this graph. If you dont understand it its because you just dont know how this stuff works. Not trying to be a dick but I know one on here that always discredits everything.

In conclusion the data logging has proven that the oil/clearance issue that bmw designed was wrong. You just cant spin a engine over 8k rpm with barely 4gpm of oil flow. We all see the results of it. Furthermore we build all types of race engines. Not a single one,even a restrictor plate engine can survive on that flow. Yea we might only run 40psi at 9k but it still has even more than 7gpm. Even then the rob bearings are so beat out of it after a race they wont even stay in the rod by them self anymore.
I enjoy helping out and bringing real racing experience to the forum (I cant talk about everything) but try as much as possible. I took a hiatus from here for a while because of all the banter for so long.
I will answer and help with any questions on here but wont argue about a 4psi loss of oil pressure when flow goes from 4 to 7.
Thank you everyone for sticking with us with the bearings, the +.001 shells we have now will allow for even better fine tuning for those who desire a full teardown rebuild. The s/c guys that run aftermarket rods will be pleased to know the clearance can be set right where it should.

[O2ShootTheJ]

So i'm sure i'm not the only one, but would someone be able to summarize the findngs in lamens terms for those of us that aren't engineers? I can't seem to make sense of the findings that were presenting

[Sneaky Pete]

Originally Posted by kawasaki00

Not trying to be a dick

and yet there you are.

Simple question then...what does an increase in RB clearance from say 0.0017 to 0.0025 predict in increased oil flow in approx % terms?

[FazerBoy]

I just don't understand how it can happen that an organisation as experienced at engine-building and as well-funded as BMW, with all their experts and technological assistance can get such a basic thing wrong. How is that possible?

Anyway, I've got a supercharged E92 M3 (ESS VT-625) and I want to keep it for the long term. I'm definitely going to do the BE bearings and ARP bolts but I'm wondering whether the main bearings are also a weak point as we have seen some main bearing failures (especially on supercharged engines).

If money was no object and I was prepared to take the motor out of the car, what work could I do to ensure a long engine life at 625bhp? Not looking for more power - just solid reliability and longevity at that power level. Any suggestions ?

Jack

[SDPLV]

So...don't ever rev over 7,600 on stock build or your rod bearings will fail!

[Green-Eggs]

Originally Posted by Sneaky Pete

and yet there you are.

Simple question then...what does an increase in RB clearance from say 0.0017 to 0.0025 predict in increased oil flow in approx % terms?

Hmmm. I knew I remembered seeing that same question somewhere before. It's the same question you refused to answer.

Originally Posted by OM VT3

Go on record and tell me how much oil pressure needs to go down before damage occurs? Can you give me a number...without changing the subject? And what's your prediction about oil flow?

Originally Posted by Sneaky Pete

Without changing the subject...Can you give me a number for how many kms the VAC coating will last?

Originally Posted by OM VT3

http://www.calicocoatings.com/company/coating-faqs/

Over the phone they have told me 25-30k miles. Now will you answer mine? Bet you won't give a number because if the real measurements come out different then you'll still have a way to claim you were right. So go on the record with a real number.

How much pressure loss will damage bearings?
What's your prediction about oil flow?

[Green-Eggs]

Originally Posted by O2ShootTheJ

So i'm sure i'm not the only one, but would someone be able to summarize the findngs in lamens terms for those of us that aren't engineers? I can't seem to make sense of the findings that were presenting

Sure, I'll take a stab at it. In stock engine form, the oil pump has plenty of capacity, but the clearances are so small they restrict oil flow to dangerous levels. BE Bearings were designed to fix this problem. The analysis above shows the factory oil pump has plenty of capacity. It shows the factory bearings have dangerously low oil flow. It shows the BE Bearings open up the clearance, the factory oil pump still has plenty of capacity, and the oil flow is sufficiently increased to much more normal and safer levels than factory bearings.

[Green-Eggs]

Originally Posted by FazerBoy

I just don't understand how it can happen that an organisation as experienced at engine-building and as well-funded as BMW, with all their experts and technological assistance can get such a basic thing wrong. How is that possible?

Anyway, I've got a supercharged E92 M3 (ESS VT-625) and I want to keep it for the long term. I'm definitely going to do the BE bearings and ARP bolts but I'm wondering whether the main bearings are also a weak point as we have seen some main bearing failures (especially on supercharged engines).

If money was no object and I was prepared to take the motor out of the car, what work could I do to ensure a long engine life at 625bhp? Not looking for more power - just solid reliability and longevity at that power level. Any suggestions ?

Jack

Yes, your main bearings might be the next weakest link. If money were no object, I'd have a custom crankshaft made to fix the main bearing clearance, and Carrillo connecting rods, and custom Mahle pistons. A much less expensive route would be to slightly regrind the main bearings on the crankshaft you have now to open up the clearance.

[L4ces]

Originally Posted by Green-Eggs

Yes, your main bearings might be the next weakest link. If money were no object, I'd have a custom crankshaft made to fix the main bearing clearance, and Carrillo connecting rods, and custom Mahle pistons. A much less expensive route would be to slightly regrind the main bearings on the crankshaft you have now to open up the clearance.

What about stroker kit? For some reason I seem to believe all the problems are addressed.

[BMRLVR]

Originally Posted by L4ces

What about stroker kit? For some reason I seem to believe all the problems are addressed.

That is definitely and option, when ordering the kit the main journals on the crank would need to be sized according to the clearance desired on the main bearings.

[Green-Eggs]

Originally Posted by L4ces

What about stroker kit? For some reason I seem to believe all the problems are addressed.

Any stroker kit you buy off of an internet vendor will be made with factory size journals on both mains and rods. So that won't fix the issue with mains. The main bearings do come in different sizes. Assuming all of your journals are perfectly within nominal spec, the main bearings only give you +/- 0.0003 inch. To size the mains properly, you need about an extra 0.00075 to 0.00100 inch (approximately 2.5x the size you get by playing with main bearings).

To address the main bearing sizes properly, you need to work with somebody who can order the custom crankshaft for you with custom size main journals to go along with it. That's going to be the only way to address the main bearing sizes. I think you'll find that will substantially limit your vendor selection. Only two vendors I know for certain that will do that for you. Both on the west coast if that gives you a hint. Not saying others won't; just saying I don't know of any others.

[Sneaky Pete]

Originally Posted by Green-Eggs

Hmmm. I knew I remembered seeing that same question somewhere before. It's the same question you refused to answer.

Hey I'm not the "expert".
Its a fairly simple question...what did you calculate the expected increase in oil flow to be.

[kawasaki00]

Originally Posted by Sneaky Pete

and yet there you are.

Simple question then...what does an increase in RB clearance from say 0.0017 to 0.0025 predict in increased oil flow in approx % terms?

Just as I suspected. The ONE person on here that would point that out. Funny dont ya think. So why did you change screen names anyway because we all know you are SFP

There is no prediction only way to know is to use the flow meter. The reason we cant predict it is you would have to dyno the oil system with the pump and have specific flow charts for the oiling system. That is just not possible unless someone wants to donate a engine just for testing. Yet to find one.
Realistically didnt care what the increase would be just need to get the clearance right to start with. With the rods all ove rthe place while running( evidence by all the rubbing on the parting lines) just have to start fixing things 1 by 1. We have discussed this before, the rods are just ok for application. BMW cant put carrillo rods in every engine due to cost. I am going on a limb here but I bet a nice set of rods would be 5hp better than the stock ones. Just because of the design and strength.
We have been running a new rod that we never would have believed was 3hp better than the current one. Everytime we tested it there is that 3hp. That is over rods that are already pretty bad ass. Just saying there is alot of power in the bottom end in these things but unlike a sbc or bbc or something like that the cost is just ridiculous.
Rambling but you know what I am getting at.

[kawasaki00]

Originally Posted by FazerBoy

I just don't understand how it can happen that an organisation as experienced at engine-building and as well-funded as BMW, with all their experts and technological assistance can get such a basic thing wrong. How is that possible?

Anyway, I've got a supercharged E92 M3 (ESS VT-625) and I want to keep it for the long term. I'm definitely going to do the BE bearings and ARP bolts but I'm wondering whether the main bearings are also a weak point as we have seen some main bearing failures (especially on supercharged engines).

If money was no object and I was prepared to take the motor out of the car, what work could I do to ensure a long engine life at 625bhp? Not looking for more power - just solid reliability and longevity at that power level. Any suggestions ?

Jack

If you are going to take it out of the car yes you should look at main clearances. Some are not as bad as others but the ones that burn the front main out because of the s/c are probably too tight. I say probably because you cant measure it after it blows up so no way to actually say.
Adjust mains, change rods to a nice H beam and a better set of pistons and it will run forever as long as you dont kill it with a super aggressive tune.

I just saw Eggs replied above, well you see we both agree on what some issues are.

[FazerBoy]

Originally Posted by kawasaki00

If you are going to take it out of the car yes you should look at main clearances. Some are not as bad as others but the ones that burn the front main out because of the s/c are probably too tight. I say probably because you cant measure it after it blows up so no way to actually say.
Adjust mains, change rods to a nice H beam and a better set of pistons and it will run forever as long as you dont kill it with a super aggressive tune.

I just saw Eggs replied above, well you see we both agree on what some issues are.

Thanks for both the replies.

I'm in the UK so don't have access to the specialists in the s65 you have in the US but I have a good engine builder who knows what he is doing.

What pistons and rods would you recommend and will the aftermarket pistons run in the standard coated bore?

Jack

[kawasaki00]

Originally Posted by FazerBoy

Thanks for both the replies.

I'm in the UK so don't have access to the specialists in the s65 you have in the US but I have a good engine builder who knows what he is doing.

What pistons and rods would you recommend and will the aftermarket pistons run in the standard coated bore?

Jack

The carrillo is the only thing I would use. Green Eggs can help you more on pistons. He is well versed in those. I have only delt with a few set so he can steer you in the direction for your application
If you have a guy that knows what he is doing yu will be fine. If doing a teardown make sure you pay attention to the side rod clearance. Not always but have seem ones that are too tight. There is a right and wrong way to fix it so let us know if you need help