Scary rod bearing thread s85

[VCMpower]

Originally Posted by kawasaki00

.0003, sorry. That is why mahle doesn't make .0005 increments. The tolerance overlaps too much.
Probably why some have seen a range of .00096 to .0015, that makes sense.
If the demand is high enough they will make -.001 bearings.

Perfect. Thanks. Possibly why some of us do not get along so well. Hopefully that can change as well.

[BMRLVR]

Originally Posted by VCMpower

Now now, condescending? Reg guy gave me the data I was looking for, thanks.

I had the info from Regular Guy long before this and I shared it with you....... At that point you were still recommending bearings as preventative maintenance items!

[VCMpower]

Originally Posted by BMRLVR

I had the info from Regular Guy long before this and I shared it with you....... At that point you were still recommending bearings as preventative maintenance items!

Agree, and now more details came out that help me understand your points. You would not just go on heresay. I have credible info on oil pressures as well and you questioned that. Whether the lower psi's were fine or not. I am glad we can understand the same info now.

[Alekshop]

Originally Posted by kawasaki00

Well you just made my mind up, I would never put coated bearing in my engine from Calico, we have failed so many of those bearings it is not even funny. Calico was good before they got bought out, now not so much.
Mahle also recommends thinner oils....Imagine that.
If they are Mahle bearings that also means they are quite inconsistent from batch to batch. Mahle has a tolerance of about +-.003 on the shells.

You should definitely consider Clevite 77 Tri-Armor instead.

Looking at the pictures of the Calico bearings that VAC is selling, you can see that parting lines are also coated.

Coating parting lines is an issues
since it can increase the total crush effect by .0012 (.0003 x 4).

Initially, this causes the bore to become distorted.

Then overtime as the coating extrudes from the parting line faces, the bearing loses its tight fit in the housing potentially causing additional problems.

No one seems to cover that so hopefully it helps.

[VCMpower]

Originally Posted by Alekshop

You should definitely consider Clevite 77 Tri-Armor instead.

Looking at the pictures of the Calico bearings that VAC is selling, you can see that parting lines are also coated.

Coating parting lines is an issues
since it can increase the total crush effect by .0012 (.0003 x 4).

Initially, this causes the bore to become distorted.

Then overtime as the coating extrudes from the parting line faces, the bearing loses its tight fit in the housing potentially causing additional problems.

No one seem to cover that so hopefully it helps.

I literally just sat here and measured VAC and oem bearings( both new ). Surprisingly the vac's measured at .0765 and stock .077. Go figure. For curiosity I used emery and the ends of the bearings that are coated can easily be removed. I can't see the end coating being a issue though.

[BMRLVR]

Good info, the coating on the parting line could be a huge issue...... It could cause the bearing crush to be wrong as pointed out by Alekshop which would make it not fit the journal properly!

[Alekshop]

Originally Posted by VCMpower

I literally just sat here and measured VAC and oem bearings( both new ). Surprisingly the vac's measured at .0765 and stock .077. Go figure. For curiosity I used emery and the ends of the bearings that are coated can easily be removed. I can't see the end coating being a issue though.

Non of it can be considered as an issue unless you know about it.

Why removing something when you can buy a product that was properly coated in the first place.

[VCMpower]

Originally Posted by Alekshop

Non of it can be considered as an issue unless you know about it.

Why removing something when you can buy a product that was properly coated in the first place.

I hear ya. Sounds like a quote from Galileo Galilei.

[vinniechin]

Great thread guys! Thanks for all the information.

[US///M3]

I think for those who track their M3's, oil pan baffles, a dry sump oil kit maybe what's needed.
I think under certain conditions the oil pump isn't sending the right amount of oil/ oil pressure.
BMW sensors usually are slow to notice a quick drop in oil pressure.
There must be a reason the E36 LTW (dual oil pick-up sumps), E46 M3 CSL received similar upgrades.

[Longwong]

Can someone summarize what we have learned here for us mere mortals? What my take away is

1. The issue is bmw made the clearence for oil to properly lubricate the bearings so ridiculously small because speculation that they were doing it for noise reduction or increase in power? At the expense of not having enough clearence for the thick oil they recommend

2.Mahle recommends 5w30 with the clearences bmw is using. So why don't we all switch to 5w 30? Can someone explain the cost vs benefit of those who don't know how 5w 30 may hold up at 8k rpm?

3. No point to coated bearings for 2 reasons. First it may worsen the problem since the coating further reduces the clearences. Second even if not, it still does not fix the problem of under lubrication and the coated ones will fail as well

Last are we all just doomed if we drive our cars hard? I feel like it could go at any day.

So is there literally nothing anyone can do?

Honestly with this information I cannot see how anyone in their right mind would supercharge this car. I was going to but no way in hell now.

Any particular driving habits worse for bearing starvation? Is it a high rpm issue or hard banking on turns issue? Can someone explain

[VCMpower]

This is the type of feedback we need if BMW is going to pay any attention, just don't say you're going to run out and bye a M4! Lol

[regular guy]

For all you supercharged guys, if you want the real bombshell, here it is. Instead of using my own words, I'll quote this directly from a Mahle-Clevite white paper on bearing clearance, then I'll summarize at the end.

For most applications .00075 to .0010” (three quarters to one thousandth of an inch) of clearance per inch of shaft diameter is a reasonable starting point.

...

Using this formula will provide a safe starting point for most applications. For High Performance engines it is recommended that .0005” be added to the maximum value determined by the above calculation. The recommendation for our 2.000” shaft would be .0025” of clearance.

...

High Performance engines on the other hand, typically employ greater bearing clearances for a number of reasons. Their higher operating speeds result in considerably higher oil temperatures and an accompanying loss in oil viscosity due to fluid film friction that increases with shaft speed. Increased clearance provides less sensitivity to shaft, block, and connecting rod deflections and the resulting misalignments that result from the higher levels of loading in these engines. Use of synthetic oils with their better flow properties
can help to reduce fluid film friction.

...

Use of these coated bearings may result in slightly less clearance than the uncoated CLEVITE 77® high performance parts for the same application. This will typically be in the range of .0005.” This is because the coating, although expected to remain in place during service, is considered to be somewhat of a sacrificial layer. Some amount of the coating will be removed during break-in and operation, resulting in a slight increase in clearance.

Here's what this means to you. If you run high horsepower and high RPM, then you need extra bearing clearance, not less of it. The coated bearings are great, but you have to size your journals for them; and as Alekshop mentioned, you shouldn't have coated parting lines. If you have coated parting lines you must remove the coating in this area before using these bearings.

Mahle-Clevite recommends adding an extra 0.0005 for good measure for high horsepower, high RPM, and coated bearing applications. To see some numbers in real life, please see the following examples.

Factory clearance: 0.0010
Factory clearance with Calico coated bearings: 0.0006 - 0.0008 (20-40% smaller).
Factory clearance with TriArmor coated bearigns: 0.0005 - 0.0007 (30-50% smaller).

Recommended clearance for mains (70mm journal):
0.00100/inch + 0.0005 = 0.00325
0.00075/inch + 0.0005 = 0.00256

Recommended clearance for rods (53mm journal):
0.00100/inch + 0.0005 = 0.00258
0.00075/inch + 0.0005 = 0.00206

So there you have it: ideal mains should be 0.0025 - 0.0032 and ideal rods should be 0.0020 - 0.0025. You're given 0.0010 clearance from the factory and some may be thinking of reducing it another 20-50% with coated bearings without sizing the journals because they believe it gives them extra protection. The extra protection is true if you kept all things the same including the bearing clearance; but reducing the bearing clearance by 20-50% to get the extra protection of the coating is not recommended.

Our next engine will get the Mahle-Clevite TriArmor bearings if we can still find them -- of course with proper clearance to match.

I hope this helps.

[Longwong]

If I read that correctly, part of the problem with low clearence is the chance the oil will sheer and especially at high performance and high engine speeds will cause the thinner oils to lose protective layer. So this means that is likely why bmw uses the thicker TWS oil (remember the e46 m3 started with 5w30 and switched to TWS after the bearing issues) so going to a thinner oil would in theory "fix" the problem of oil getting into the lower clearence areas but would sheer and the protection would be useless and thus it looks like TWS is the best protection for a low clearence situation like we have.

I just have no clue how bmw could not have caught this and did it again with the s85/s65 blocks/engines after the s54. Such a small little detail yet so catastrophic.

So essentially coated bearingas are not the answer. Thinner oil is not the answer. Praying that we have the bearings with a bit more clearence than the next guys is the only hope!

[Longwong]

If I read that correctly, part of the problem with low clearence is the chance the oil will sheer and especially at high performance and high engine speeds will cause the thinner oils to lose protective layer. So this means that is likely why bmw uses the thicker TWS oil (remember the e46 m3 started with 5w30 and switched to TWS after the bearing issues) so going to a thinner oil would in theory "fix" the problem of oil getting into the lower clearence areas but would sheer and the protection would be useless and thus it looks like TWS is the best protection for a low clearence situation like we have.

I just have no clue how bmw could not have caught this and did it again with the s85/s65 blocks/engines after the s54. Such a small little detail yet so catastrophic.

So essentially coated bearingas are not the answer. Thinner oil is not the answer. Praying that we have the bearings with a bit more clearence than the next guys is the only hope!

[BIU]

Appreciating all this discussion with very valuable info. from the technical gurus and Longwong for somewhat breaking it down to caveman lingo for the avg. joe

[Transfer]

Wow have I learned a ton in this thread. Thank you to all contributing who know so much about this stuff because some of us are totally in the dark. Subscribed!

[aussiem3]

Originally Posted by regular guy

For all you supercharged guys, if you want the real bombshell, here it is. Instead of using my own words, I'll quote this directly from a Mahle-Clevite white paper on bearing clearance, then I'll summarize at the end.

For most applications .00075 to .0010” (three quarters to one thousandth of an inch) of clearance per inch of shaft diameter is a reasonable starting point.

...

Using this formula will provide a safe starting point for most applications. For High Performance engines it is recommended that .0005” be added to the maximum value determined by the above calculation. The recommendation for our 2.000” shaft would be .0025” of clearance.

...

High Performance engines on the other hand, typically employ greater bearing clearances for a number of reasons. Their higher operating speeds result in considerably higher oil temperatures and an accompanying loss in oil viscosity due to fluid film friction that increases with shaft speed. Increased clearance provides less sensitivity to shaft, block, and connecting rod deflections and the resulting misalignments that result from the higher levels of loading in these engines. Use of synthetic oils with their better flow properties
can help to reduce fluid film friction.

...

Use of these coated bearings may result in slightly less clearance than the uncoated CLEVITE 77® high performance parts for the same application. This will typically be in the range of .0005.” This is because the coating, although expected to remain in place during service, is considered to be somewhat of a sacrificial layer. Some amount of the coating will be removed during break-in and operation, resulting in a slight increase in clearance.

Here's what this means to you. If you run high horsepower and high RPM, then you need extra bearing clearance, not less of it. The coated bearings are great, but you have to size your journals for them; and as Alekshop mentioned, you shouldn't have coated parting lines. If you have coated parting lines you must remove the coating in this area before using these bearings.

Mahle-Clevite recommends adding an extra 0.0005 for good measure for high horsepower, high RPM, and coated bearing applications. To see some numbers in real life, please see the following examples.

Factory clearance: 0.0010
Factory clearance with Calico coated bearings: 0.0006 - 0.0008 (20-40% smaller).
Factory clearance with TriArmor coated bearigns: 0.0005 - 0.0007 (30-50% smaller).

Recommended clearance for mains (70mm journal):
0.00100/inch + 0.0005 = 0.00325
0.00075/inch + 0.0005 = 0.00256

Recommended clearance for rods (53mm journal):
0.00100/inch + 0.0005 = 0.00258
0.00075/inch + 0.0005 = 0.00206

So there you have it: ideal mains should be 0.0025 - 0.0032 and ideal rods should be 0.0020 - 0.0025. You're given 0.0010 clearance from the factory and some may be thinking of reducing it another 20-50% with coated bearings without sizing the journals because they believe it gives them extra protection. The extra protection is true if you kept all things the same including the bearing clearance; but reducing the bearing clearance by 20-50% to get the extra protection of the coating is not recommended.

Our next engine will get the Mahle-Clevite TriArmor bearings if we can still find them -- of course with proper clearance to match.

I hope this helps.

By the way, who are you? You are new here but seem to know a lot more than some of our forum pros. I am sure you would have been living in a cave to sign up now. Anyway, very good information and educating too. Thank you.

[kawasaki00]

The only way to fix it without taking the engine apart is to have mahle make -.001 bearings and swap shells, that would effectively give you about .002 clearance.
Oh I also believe that BMW should pay for it and eat the cost of replacing them. Although many of us have not had failures the simple fact that as the m3 and m5 age more failures are creeping up. The clearance they set the engines at is not acceptable in any machine shop across the entire planet. If they dont have at least some sort of response it is pretty lame if you ask me. Many of us know what it takes to fix it and some of us have all the tools neede to fix it ourself, but I have a problem with pulling a 15 thousand dollar engine out of my car and having to fix it myself. On the other hand most of us sit here and think about it everytime you make a blast up a back road or freeway wondering if it is going to spit the rods out.

[Richbot]

Originally Posted by Longwong

If I read that correctly, part of the problem with low clearence is the chance the oil will sheer and especially at high performance and high engine speeds will cause the thinner oils to lose protective layer. So this means that is likely why bmw uses the thicker TWS oil (remember the e46 m3 started with 5w30 and switched to TWS after the bearing issues) so going to a thinner oil would in theory "fix" the problem of oil getting into the lower clearence areas but would sheer and the protection would be useless and thus it looks like TWS is the best protection for a low clearence situation like we have.

I just have no clue how bmw could not have caught this and did it again with the s85/s65 blocks/engines after the s54. Such a small little detail yet so catastrophic.

So essentially coated bearingas are not the answer. Thinner oil is not the answer. Praying that we have the bearings with a bit more clearence than the next guys is the only hope!

it's obvious this was an intentional decision by BMW, who knows why, only they do probably. Perhaps too reliant on their suppliers to make parts to a tolerance they couldn't meet, perhaps too reliant on the idea that most M car owners use wide open throttle less than once a month...

This is why some have tried race oils like the redline 40wt with good if inconclusive results

[Obioban]

Originally Posted by US///M3

I think for those who track their M3's, oil pan baffles, a dry sump oil kit maybe what's needed.
I think under certain conditions the oil pump isn't sending the right amount of oil/ oil pressure.
BMW sensors usually are slow to notice a quick drop in oil pressure.
There must be a reason the E36 LTW (dual oil pick-up sumps), E46 M3 CSL received similar upgrades.

Got a source on that? Pretty sure the CSL used the standard e46 M3 oiling system in all respects...

[BASELINE]

So...

Basically there is no reasonable recourse at this time. No bolt on upgrade.

Am I incorrect to surmise that if someone wanted to "service" this issue on a higher mileage car at this point going with the stock ones is probably the safest option? I guess one could do the ARP bolts but I'm reading a "NO" on the current coated offerings.

Perhaps