Bearing clearance discussion!

[OM VT3]

Originally Posted by M3PO

Keep posting, this is valuable information about a REAL issue. My bearings are well on their way to failing.

How do you know that?

[kawasaki00]

Originally Posted by flipmeraz

What should the pressure be at during idle? Operating temp under load?

25psi is the minimum I would want to see. I have had mine to 240ish and it still was at 32 at idle.

[Yellow Snow]

I have the journal measurements of an S85 (same spec as S65)that I worked on last year. All journals were as near as makes no difference 51.982 diameter. This car showed no abnormal signs of wear at 78k miles, so the old shells went back in.

I also have a new pair of rod bearings in front of me. They are measuring:

.0785" (1.9939mm) in the centre of the blue 703 bearing, .077 ish near the split
.0783" (1.9888mm) in the centre of the red 702 bearing, with .077" again near the split.









Assuming the rod was at mid limit of 56.007mm, this would give a clearance value of .0016" (.042mm) at 90 degrees to the split line. Clearance at the split line oval bore would be .0044" (.11mm)

This clearance seems fair enough for an 8,400rpm motor when allowing for rod stretch.

What concerned me about the bearings is the split lines aren't as flat as they should be. Any good engine builder will wipe a fine stone across the splits before assembly to remove slight burring and subsequent distortion. Was this done at the factory assembly stage?

Both bearings are identical apart from the .0002" thickness reduction. Why do the blues cost 50% more? Different material?

The crank that I measured gave good clearance out of the box. If the journals had been ground to top limit and used with a rod set at bottom limit, clearance would be close to .001"

It would be interesting to see a log file of actual journal measurements from anyone who has the opportunity to mic a crank

Could the sporadic nature of this problem be down to one bad assembly worker

[thekurgan]

Those bearings (703/702) look like the aluminum bi-metal type?

[regular guy]

Originally Posted by Yellow Snow

I have the journal measurements of an S85 (same spec as S65)that I worked on last year. All journals were as near as makes no difference 48.982 diameter. This car showed no abnormal signs of wear at 78k miles, so the old shells went back in.

I also have a new pair of rod bearings in front of me. They are measuring:

.0785" (1.9939mm) in the centre of the blue 703 bearing, .077 ish near the split
.0783" (1.9888mm) in the centre of the red 702 bearing, with .077" again near the split.









Assuming the rod was at mid limit of 53.007mm, this would give a clearance value of .0016" (.042mm) at 90 degrees to the split line. Clearance at the split line oval bore would be .0044" (.11mm)

This clearance seems fair enough for an 8,400rpm motor when allowing for rod stretch.

What concerned me about the bearings is the split lines aren't as flat as they should be. Any good engine builder will wipe a fine stone across the splits before assembly to remove slight burring and subsequent distortion. Was this done at the factory assembly stage?

Both bearings are identical apart from the .0002" thickness reduction. Why do the blues cost 50% more? Different material?

The crank that I measured gave good clearance out of the box. If the journals had been ground to top limit and used with a rod set at bottom limit, clearance would be close to .001"

It would be interesting to see a log file of actual journal measurements from anyone who has the opportunity to mic a crank

Could the sporadic nature of this problem be down to one bad assembly worker

Here's a couple of things I've learned along the way. Be sure to measure the journals and bearing clearance at the same temperature range -- typically at the same sitting. I've measured them change size with temperature. The rod/bearing bore can't be measured untorqued by subtracting bearing thickness from rod bore diameter. Bearing thickness can't be calculated that way. The rod must be torqued with the bearing in place, and measurements taken with a bore gauge on the assembly. Ideally you would calibrate the bore gauge to actual journal measurement micrometer and then use the bore gauge to show the delta (clearance). Kawasaki and my own engine builder helped steer me in the right direction for best practice in measuring bearing clearance.

Previously, I've posted journal measurements on three different cranks journals. Mics were 0.00005 accuracy. I don't have the links handy at the moment, but they shouldn't be too hard to find. This weekend I'll be finalizing some of the latest measurements with my engine builder and then will be posting the full set of measurements next week on an engine we disassembled a week ago.

Regarding blue/red rod bearings. I don't think anybody here has posted a definitive answer yet. BMW engine builders swear they are different bearings (upper/lower). Here's something I found on another site.

Using a clean-room wipe and isopropyl alcohol, carefully clean each rod bearing (see Photo 4). Install each bearing into the rod cap and rod half. Depending upon which engine you have, there may be upper and lower bearing shell halves (blue for the top side and red for the lower side near the rod cap).

http://www.pelicanparts.com/bmw/tech...d-Bearings.htm

I hope this helps...

[jcolley]

Seems I need to visit here more often. Missed this thread, but tagging along now.

I have a set of bearings in-hand for swap in my S85 in a couple of weeks. I'm doing this as a preventive item in-car, so the discussion of the oversized bearings now has me wondering.

If you (anyone here) were given the choice of .25mm oversized bearings and TWS or original spec and 0W-40, which would you go with? I'm not going to lie, I was looking forward to $60 oil changes...

Combine that with a 5 mile round trip work commute and Maine winter temps, am I out of the box to think the oversize bearings are the real solution and the Mobil1 0-40W is my winter oil of choice and TWS when the snow tires come off?

[e92zero]

Originally Posted by regular guy

Here's a couple of things I've learned along the way. Be sure to measure the journals and bearing clearance at the same temperature range -- typically at the same sitting. I've measured them change size with temperature. The rod/bearing bore can't be measured untorqued by subtracting bearing thickness from rod bore diameter. Bearing thickness can't be calculated that way. The rod must be torqued with the bearing in place, and measurements taken with a bore gauge on the assembly. Ideally you would calibrate the bore gauge to actual journal measurement micrometer and then use the bore gauge to show the delta (clearance). Kawasaki and my own engine builder helped steer me in the right direction for best practice in measuring bearing clearance.

Previously, I've posted journal measurements on three different cranks journals. Mics were 0.00005 accuracy. I don't have the links handy at the moment, but they shouldn't be too hard to find. This weekend I'll be finalizing some of the latest measurements with my engine builder and then will be posting the full set of measurements next week on an engine we disassembled a week ago.

Regarding blue/red rod bearings. I don't think anybody here has posted a definitive answer yet. BMW engine builders swear they are different bearings (upper/lower). Here's something I found on another site.

Using a clean-room wipe and isopropyl alcohol, carefully clean each rod bearing (see Photo 4). Install each bearing into the rod cap and rod half. Depending upon which engine you have, there may be upper and lower bearing shell halves (blue for the top side and red for the lower side near the rod cap).

http://www.pelicanparts.com/bmw/tech...d-Bearings.htm

I hope this helps...

I guess this means that we cannot use 2 red bearings to increase the clearance then?

[kawasaki00]

Originally Posted by e92zero

I guess this means that we cannot use 2 red bearings to increase the clearance then?

Originally Posted by regular guy

Here's a couple of things I've learned along the way. Be sure to measure the journals and bearing clearance at the same temperature range -- typically at the same sitting. I've measured them change size with temperature. The rod/bearing bore can't be measured untorqued by subtracting bearing thickness from rod bore diameter. Bearing thickness can't be calculated that way. The rod must be torqued with the bearing in place, and measurements taken with a bore gauge on the assembly. Ideally you would calibrate the bore gauge to actual journal measurement micrometer and then use the bore gauge to show the delta (clearance). Kawasaki and my own engine builder helped steer me in the right direction for best practice in measuring bearing clearance.

Previously, I've posted journal measurements on three different cranks journals. Mics were 0.00005 accuracy. I don't have the links handy at the moment, but they shouldn't be too hard to find. This weekend I'll be finalizing some of the latest measurements with my engine builder and then will be posting the full set of measurements next week on an engine we disassembled a week ago.

Regarding blue/red rod bearings. I don't think anybody here has posted a definitive answer yet. BMW engine builders swear they are different bearings (upper/lower). Here's something I found on another site.

Using a clean-room wipe and isopropyl alcohol, carefully clean each rod bearing (see Photo 4). Install each bearing into the rod cap and rod half. Depending upon which engine you have, there may be upper and lower bearing shell halves (blue for the top side and red for the lower side near the rod cap).

http://www.pelicanparts.com/bmw/tech...d-Bearings.htm

I hope this helps...

If someone would be so kind as to send me one of each I will call my buddie at Clevite and find out. With out a specimen in front of me I really cant comment on the bearing itself. Hint Hint lol

[M3PO]

Originally Posted by leigh

How do you know that?

I have consistently had bad UOAs. My oil is showing significant levels of copper, signifying that I have worn into the intermediate layer. Also, I think it is beginning to develop a tick. I need to listen to some cars to make sure what I am hearing is not normal though.

[8k3]

Originally Posted by M3PO

I have consistently had bad UOAs. My oil is showing significant levels of copper, signifying that I have worn into the intermediate layer. Also, I think it is beginning to develop a tick. I need to listen to some cars to make sure what I am hearing is not normal though.

how many miles?

[OM VT3]

Originally Posted by M3PO

I have consistently had bad UOAs. My oil is showing significant levels of copper, signifying that I have worn into the intermediate layer. Also, I think it is beginning to develop a tick. I need to listen to some cars to make sure what I am hearing is not normal though.

I always think mine has a tick but there all the same

[regular guy]

Originally Posted by kawasaki00

If someone would be so kind as to send me one of each I will call my buddie at Clevite and find out. With out a specimen in front of me I really cant comment on the bearing itself. Hint Hint lol

I could send you the 090/091's oversize bearings early next week. I assume you don't need the 088/089's...right? We have plans for the 088/089's to have them "treated" to see how the thickness changes.

[regular guy]

Originally Posted by Yellow Snow

I have the journal measurements of an S85 (same spec as S65)that I worked on last year. All journals were as near as makes no difference 48.982 diameter. This car showed no abnormal signs of wear at 78k miles, so the old shells went back in.

Shouldn't the rod journals be closer to 52mm?

Could the sporadic nature of this problem be down to one bad assembly worker

Possible. Another possibility is a journal at the upper tolerance spec mated with a rod/bearing at the lower tolerance spec. Put the two together...and boom goes the dynamite. But there aren't enough measurements collected yet to know if that's the case.

[Yellow Snow]

Originally Posted by regular guy

Shouldn't the rod journals be closer to 52mm?



Possible. Another possibility is a journal at the upper tolerance spec mated with a rod/bearing at the lower tolerance spec. Put the two together...and boom goes the dynamite. But there aren't enough measurements collected yet to know if that's the case.

Sorry yes, my mistake they are a nominal 52mm. I have figures noted here at -.018mm, so I should have said 51.982mm. I will edit.

That's what I mean about the bad builder. If they mixed a low end tolerance rod end with a high end tolerance journal things will be getting tight. Mix that with a distorted shell and it's not good news

[aussiem3]

One of the local master technicians met with the senior /// engineer from Germany. The word is that BMW acknowledges that there is bearing issue due to tight clearance. But BMW will assess each failure on a case-by-case basis and extend a goodwill warranty cover. The catch is that, the car must have an ongoing dealership service history, at least oil changes, to confirm factory spec oil and filter have been used each time. If this is the case, regardless of the miles or years, BMW will help owners out.

I've heard this from a very reliable third party. I am just putting it out there for information only. No flame please.

Also the same /// engineer was quoted saying, hang on to the ///3s with S65 engines because it's last of the /// cars with /// DNA and built at the /// centre (I don't know much about this one). All current and future /// cars including 3, 5 and 6 will be series builds along with other non-/// cars.

[thekurgan]

Originally Posted by aussiem3

One of the local master technicians met with the senior /// engineer from Germany. The word is that BMW acknowledges that there is bearing issue due to tight clearance. But BMW will assess each failure on a case-by-case basis and extend a goodwill warranty cover. The catch is that, the car must have an ongoing dealership service history, at least oil changes, to confirm factory spec oil and filter have been used each time. If this is the case, regardless of the miles or years, BMW will help owners out.

I've heard this from a very reliable third party. I am just putting it out there for information only. No flame please.

Also the same /// engineer was quoted saying, hang on to the ///3s with S65 engines because it's last of the /// cars with /// DNA and built at the /// centre (I don't know much about this one). All current and future /// cars including 3, 5 and 6 will be series builds along with other non-/// cars.

Goodwill with the Castrol TWS eh?

[lsmkr01]

Originally Posted by aussiem3

One of the local master technicians met with the senior /// engineer from Germany. The word is that BMW acknowledges that there is bearing issue due to tight clearance. But BMW will assess each failure on a case-by-case basis and extend a goodwill warranty cover. The catch is that, the car must have an ongoing dealership service history, at least oil changes, to confirm factory spec oil and filter have been used each time. If this is the case, regardless of the miles or years, BMW will help owners out.

Also the same /// engineer was quoted saying, hang on to the ///3s with S65 engines because it's last of the /// cars with /// DNA and built at the /// centre (I don't know much about this one). All current and future /// cars including 3, 5 and 6 will be series builds along with other non-/// cars.

If BMW really means it they would put it in writing. To expect a car to continue to go to the dealer for every oil change (during and after service warranty with the ridiculous 15k mile intervals they specify) is absurd considering how many owners DIY in their own driveway. I also find it hard to believe they will help out regardless of time or miles but i'd love to be proven wrong in this case.

[aussiem3]

I've just got a quote for bearings change A$3500. My car is coming up six years and has done 39k km, and in the process of the change if bearings are on the way out, it will be a warranty claim and I don't have to pay a cent. I am still toying with the idea of outlaying that kind of money for the same bearing and the headache to resurface in a few years time. But the upside is, I might get the job done free even for a few more years of headache free driving.

[aussiem3]

Originally Posted by lsmkr01

If BMW really means it they would put it in writing. To expect a car to continue to go to the dealer for every oil change (during and after service warranty with the ridiculous 15k mile intervals they specify) is absurd considering how many owners DIY in their own driveway. I also find it hard to believe they will help out regardless of time or miles but i'd love to be proven wrong in this case.

The master tech know the real reason behind the tight clearance having heard from this /// engineer. But he won't share it with me.

I am in the same boat with regard to the servicing. The car hasn't seen the dealership since it went out of warranty. But I am thinking now, whether I should take it for an oil service every now and then just so that they have a record of oil visits.

[lsmkr01]

Originally Posted by aussiem3

The master tech know the real reason behind the tight clearance having heard from this /// engineer. But he won't share it with me.

I am in the same boat with regard to the servicing. The car hasn't seen the dealership since it went out of warranty. But I am thinking now, whether I should take it for an oil service every now and then just so that they have a record of oil visits.

I hope this comes to light in the near future. I started a 5k oil interval service so taking it in every 3rd change to keep the record wouldn't be a terrible idea. Please, let us know if you end up hearing more information on this.

[PhillyNate]

Originally Posted by Yellow Snow

I have the journal measurements of an S85 (same spec as S65)that I worked on last year. All journals were as near as makes no difference 51.982 diameter. This car showed no abnormal signs of wear at 78k miles, so the old shells went back in.

I also have a new pair of rod bearings in front of me. They are measuring:

.0785" (1.9939mm) in the centre of the blue 703 bearing, .077 ish near the split
.0783" (1.9888mm) in the centre of the red 702 bearing, with .077" again near the split.









Assuming the rod was at mid limit of 56.007mm, this would give a clearance value of .0016" (.042mm) at 90 degrees to the split line. Clearance at the split line oval bore would be .0044" (.11mm)

This clearance seems fair enough for an 8,400rpm motor when allowing for rod stretch.

What concerned me about the bearings is the split lines aren't as flat as they should be. Any good engine builder will wipe a fine stone across the splits before assembly to remove slight burring and subsequent distortion. Was this done at the factory assembly stage?

Both bearings are identical apart from the .0002" thickness reduction. Why do the blues cost 50% more? Different material?

The crank that I measured gave good clearance out of the box. If the journals had been ground to top limit and used with a rod set at bottom limit, clearance would be close to .001"

It would be interesting to see a log file of actual journal measurements from anyone who has the opportunity to mic a crank

Could the sporadic nature of this problem be down to one bad assembly worker

Now THIS is interesting! Thanks

[kawasaki00]

Originally Posted by aussiem3

One of the local master technicians met with the senior /// engineer from Germany. The word is that BMW acknowledges that there is bearing issue due to tight clearance. But BMW will assess each failure on a case-by-case basis and extend a goodwill warranty cover. The catch is that, the car must have an ongoing dealership service history, at least oil changes, to confirm factory spec oil and filter have been used each time. If this is the case, regardless of the miles or years, BMW will help owners out.

I've heard this from a very reliable third party. I am just putting it out there for information only. No flame please.

Also the same /// engineer was quoted saying, hang on to the ///3s with S65 engines because it's last of the /// cars with /// DNA and built at the /// centre (I don't know much about this one). All current and future /// cars including 3, 5 and 6 will be series builds along with other non-/// cars.

I hope this is true, but I am not going to take a chance of MAYBE they will cover it just because I let the dealership do the oil changes.

Originally Posted by aussiem3

The master tech know the real reason behind the tight clearance having heard from this /// engineer. But he won't share it with me.

I am in the same boat with regard to the servicing. The car hasn't seen the dealership since it went out of warranty. But I am thinking now, whether I should take it for an oil service every now and then just so that they have a record of oil visits.

The real reason is because they screwed up and they dont want to admit it.