Bearing clearance discussion!

[KmndntKlink]

I also must thank you for your comments on that doozie of a thread. I am now armed with more knowledge to make sure my car lasts forever. Much appreciated good sir!

[Sapper_M3]

Originally Posted by pkim1079

Good idea but id rather not have bmw deny warranty on a blown motor because of not using the recommended oil. Maybe after warranty.

While I definitely appreciate outside input from automotive professionals, pkim makes a very good point here. Until I'm out of warranty, I'm going to keep following BMW's guidelines.

It would be a shame if that reduces the life of my engine, but that's the game of chance I'm playing to protect myself against BMW denying me any potential major warranty claims.

[JTO24]

I just started as an applications engineer at a global bearing company! So keep up the posts; it gives me an excuse to be on the site at work I'll tell em it's supplemental training.

[BMRLVR]

Originally Posted by JTO24

I just started as an applications engineer at a global bearing company! So keep up the posts; it gives me an excuse to be on the site at work I'll tell em it's supplemental training.

Hopefully you can be a contributor to our discussion! Good to have a person working in the bearing field on here!

[lsmkr01]

Keep sharing your knowledge because I for one will continue to read your posts.

[JEllis]

Personally I enjoy the conversation and I have to admit, some of the points about oil weight are extremely compelling despite my initial "outrage".

[IMG]

Originally Posted by regular guy

We all thought the same thing and many arguments have been fought over this topic. But a few weeks ago, I got to the bottom of it. Realoem removed the old part number from their database, and this is why we all thought the rod bearing part number had not changed.

Here's what I posted in another thread:

Got a lot more information. There have apparently been three different S65 crankshafts, and two sets of connecting rods. Maybe somebody with better BMW connections (hint, hint, Tom@EAS) can fill in the blanks. You will be surprised, I even found +.001 bearings and they are currently available!

BTW, this wasn't easy to track down. Had to look in catalogs out of country, etc. Called local dealer and confirmed they are all valid part numbers, and +size bearings are still available using these part numbers.

Crankshafts:
11 21 7 838 641 Crankshaft, Ended (no date given), no weight given
11 21 7 841 658 Crankshaft, Ended (October 2008), 20.400 kg
11 21 0 443 639 Crankshaft, Current production, 23.840 kg

Main Bearings:
11 21 7 841 488 Main Bearing Top, Yellow, Ended (October 2008)
11 21 7 841 609 Main Bearing Top, Yellow, Replaced 488 bearing
11 21 7 841 489 Main Bearing Top, Green, Ended (October 2008)
11 21 7 841 610 Main Bearing Top, Green, Replaced 489 bearing
11 21 7 841 490 Main Bearing Top, Violet, Ended (October 2008)
11 21 7 841 611 Main Bearing Top, Violet, Replaced 490 bearing
11 21 7 841 483 Main Bearing Bottom, Yellow, Ended (October 2008)
11 21 7 841 605 Main Bearing Bottom, Yellow, Replaced 483 bearing
11 21 7 841 484 Main Bearing Bottom, Green, Ended (October 2008)
11 21 7 841 606 Main Bearing Bottom, Green, Replaced 484 bearing
11 21 7 841 485 Main Bearing Bottom, Violet, Ended (October 2008)
11 21 7 841 607 Main Bearing Bottom, Violet, Replaced 485 bearing

Rod Bearings:
11 24 7 838 089 Rod Bearing Blue, 53.000 mm, +0.000 mm, Ended (no date given, but hints at July '08)
11 24 7 841 703 Rod Bearing Blue, 53.000 mm, +0.000 mm, Replacement for 089 bearing.
11 24 7 838 091 Rod Bearing Blue, 52.750 mm, +0.250 mm, Currently available

11 24 7 838 088 Rod Bearing Red, 53.000 mm, +0.000 mm, Ended (no date given, but hints at July '08)
11 24 7 841 702 Rod Bearing Red, 53.000 mm, +0.000 mm, Replacement for 088 bearing.
11 24 7 838 090 Rod Bearing Red, 52.750 mm, +0.250 mm, Currently available

I have verbal confirmation that some bearings replaced at another SoCal shop have 088/089 stamped on the back. So this would be pretty strong evidence along with information posted by Tom & B767capt that the rod bearings have indeed been superseded since production began. Most likely they were superseded in October 2008 when the crankshaft and main bearings were superseded. I will take pictures when I see these bearings in person.

Since I posted this, I ordered and received samples of each of these rod bearings including the oversized bearings. Yesterday, I measured and photographed all of the rod bearings.

Rod Bearings:
11 24 7 838 089 Blue, 53.000 mm, +0.000 mm, 0.07890" Thick, Ended
11 24 7 841 703 Blue, 53.000 mm, +0.000 mm, 0.07890" Thick, Replacement for 089 bearing
11 24 7 838 091 Blue, 52.750 mm, +0.250 mm, 0.08370" Thick, Currently available

11 24 7 838 088 Red, 53.000 mm, +0.000 mm, 0.07875" Thick, Ended
11 24 7 841 702 Red, 53.000 mm, +0.000 mm, 0.07875" Thick, Replacement for 088 bearing
11 24 7 838 090 Red, 52.750 mm, +0.250 mm, 0.08370" Thick, Currently available

Here's a photo of the old and new bearings side-by-side with part numbers shown. As seen in the photo, the bearing surfaces are quite different.

Attachment 913003

Very informative as well, +1

[klammer]

Tons of great info, love the detail and insight, keep posting!!!

[GIdriver]

Originally Posted by regular guy

We all thought the same thing and many arguments have been fought over this topic. But a few weeks ago, I got to the bottom of it. Realoem removed the old part number from their database, and this is why we all thought the rod bearing part number had not changed.

Here's what I posted in another thread:

Got a lot more information. There have apparently been three different S65 crankshafts, and two sets of connecting rods. Maybe somebody with better BMW connections (hint, hint, Tom@EAS) can fill in the blanks. You will be surprised, I even found +.001 bearings and they are currently available!

BTW, this wasn't easy to track down. Had to look in catalogs out of country, etc. Called local dealer and confirmed they are all valid part numbers, and +size bearings are still available using these part numbers.

Crankshafts:
11 21 7 838 641 Crankshaft, Ended (no date given), no weight given
11 21 7 841 658 Crankshaft, Ended (October 2008), 20.400 kg
11 21 0 443 639 Crankshaft, Current production, 23.840 kg

Main Bearings:
11 21 7 841 488 Main Bearing Top, Yellow, Ended (October 2008)
11 21 7 841 609 Main Bearing Top, Yellow, Replaced 488 bearing
11 21 7 841 489 Main Bearing Top, Green, Ended (October 2008)
11 21 7 841 610 Main Bearing Top, Green, Replaced 489 bearing
11 21 7 841 490 Main Bearing Top, Violet, Ended (October 2008)
11 21 7 841 611 Main Bearing Top, Violet, Replaced 490 bearing
11 21 7 841 483 Main Bearing Bottom, Yellow, Ended (October 2008)
11 21 7 841 605 Main Bearing Bottom, Yellow, Replaced 483 bearing
11 21 7 841 484 Main Bearing Bottom, Green, Ended (October 2008)
11 21 7 841 606 Main Bearing Bottom, Green, Replaced 484 bearing
11 21 7 841 485 Main Bearing Bottom, Violet, Ended (October 2008)
11 21 7 841 607 Main Bearing Bottom, Violet, Replaced 485 bearing

Rod Bearings:
11 24 7 838 089 Rod Bearing Blue, 53.000 mm, +0.000 mm, Ended (no date given, but hints at July '08)
11 24 7 841 703 Rod Bearing Blue, 53.000 mm, +0.000 mm, Replacement for 089 bearing.
11 24 7 838 091 Rod Bearing Blue, 52.750 mm, +0.250 mm, Currently available

11 24 7 838 088 Rod Bearing Red, 53.000 mm, +0.000 mm, Ended (no date given, but hints at July '08)
11 24 7 841 702 Rod Bearing Red, 53.000 mm, +0.000 mm, Replacement for 088 bearing.
11 24 7 838 090 Rod Bearing Red, 52.750 mm, +0.250 mm, Currently available

I have verbal confirmation that some bearings replaced at another SoCal shop have 088/089 stamped on the back. So this would be pretty strong evidence along with information posted by Tom & B767capt that the rod bearings have indeed been superseded since production began. Most likely they were superseded in October 2008 when the crankshaft and main bearings were superseded. I will take pictures when I see these bearings in person.

Since I posted this, I ordered and received samples of each of these rod bearings including the oversized bearings. Yesterday, I measured and photographed all of the rod bearings.

Rod Bearings:
11 24 7 838 089 Blue, 53.000 mm, +0.000 mm, 0.07890" Thick, Ended
11 24 7 841 703 Blue, 53.000 mm, +0.000 mm, 0.07890" Thick, Replacement for 089 bearing
11 24 7 838 091 Blue, 52.750 mm, +0.250 mm, 0.08370" Thick, Currently available

11 24 7 838 088 Red, 53.000 mm, +0.000 mm, 0.07875" Thick, Ended
11 24 7 841 702 Red, 53.000 mm, +0.000 mm, 0.07875" Thick, Replacement for 088 bearing
11 24 7 838 090 Red, 52.750 mm, +0.250 mm, 0.08370" Thick, Currently available

Here's a photo of the old and new bearings side-by-side with part numbers shown. As seen in the photo, the bearing surfaces are quite different.

Attachment 913003

Thanks a lot for the info!!!

[CanAutM3]

I love reading your posts. I learn something everytime and they force me to think. Keep 'em coming

[red998]

Wait, there is something wrong with the engine?
It's a new car. That can't be right.

[thekurgan]

Originally Posted by regular guy

If BMW always knows best, and they are always right, then they wouldn't be on the third crankshaft revision for S65, and the rod bearings wouldn't have changed material from 088/089 to 702/703. That alone says they didn't think they got it right if they had to change it.

I realize the bearing change might have been mandated by law, but the crankshaft change wasn't. And if the new bearings really are better than the old, then BMW would have chosen those to begin with instead of changing them after only 12 months of production.

Just my $0.02, and please keep posting BMRLVR.

... is the Babbit layer changed to tin? Has anyone had these new part numbers utilized in a replacement?

[e92zero]

Originally Posted by regular guy

We all thought the same thing and many arguments have been fought over this topic. But a few weeks ago, I got to the bottom of it. Realoem removed the old part number from their database, and this is why we all thought the rod bearing part number had not changed.

Here's what I posted in another thread:

Got a lot more information. There have apparently been three different S65 crankshafts, and two sets of connecting rods. Maybe somebody with better BMW connections (hint, hint, Tom@EAS) can fill in the blanks. You will be surprised, I even found +.001 bearings and they are currently available!

BTW, this wasn't easy to track down. Had to look in catalogs out of country, etc. Called local dealer and confirmed they are all valid part numbers, and +size bearings are still available using these part numbers.

Crankshafts:
11 21 7 838 641 Crankshaft, Ended (no date given), no weight given
11 21 7 841 658 Crankshaft, Ended (October 2008), 20.400 kg
11 21 0 443 639 Crankshaft, Current production, 23.840 kg

Main Bearings:
11 21 7 841 488 Main Bearing Top, Yellow, Ended (October 2008)
11 21 7 841 609 Main Bearing Top, Yellow, Replaced 488 bearing
11 21 7 841 489 Main Bearing Top, Green, Ended (October 2008)
11 21 7 841 610 Main Bearing Top, Green, Replaced 489 bearing
11 21 7 841 490 Main Bearing Top, Violet, Ended (October 2008)
11 21 7 841 611 Main Bearing Top, Violet, Replaced 490 bearing
11 21 7 841 483 Main Bearing Bottom, Yellow, Ended (October 2008)
11 21 7 841 605 Main Bearing Bottom, Yellow, Replaced 483 bearing
11 21 7 841 484 Main Bearing Bottom, Green, Ended (October 2008)
11 21 7 841 606 Main Bearing Bottom, Green, Replaced 484 bearing
11 21 7 841 485 Main Bearing Bottom, Violet, Ended (October 2008)
11 21 7 841 607 Main Bearing Bottom, Violet, Replaced 485 bearing

Rod Bearings:
11 24 7 838 089 Rod Bearing Blue, 53.000 mm, +0.000 mm, Ended (no date given, but hints at July '08)
11 24 7 841 703 Rod Bearing Blue, 53.000 mm, +0.000 mm, Replacement for 089 bearing.
11 24 7 838 091 Rod Bearing Blue, 52.750 mm, +0.250 mm, Currently available

11 24 7 838 088 Rod Bearing Red, 53.000 mm, +0.000 mm, Ended (no date given, but hints at July '08)
11 24 7 841 702 Rod Bearing Red, 53.000 mm, +0.000 mm, Replacement for 088 bearing.
11 24 7 838 090 Rod Bearing Red, 52.750 mm, +0.250 mm, Currently available

I have verbal confirmation that some bearings replaced at another SoCal shop have 088/089 stamped on the back. So this would be pretty strong evidence along with information posted by Tom & B767capt that the rod bearings have indeed been superseded since production began. Most likely they were superseded in October 2008 when the crankshaft and main bearings were superseded. I will take pictures when I see these bearings in person.

Since I posted this, I ordered and received samples of each of these rod bearings including the oversized bearings. Yesterday, I measured and photographed all of the rod bearings.

Rod Bearings:
11 24 7 838 089 Blue, 53.000 mm, +0.000 mm, 0.07890" Thick, Ended
11 24 7 841 703 Blue, 53.000 mm, +0.000 mm, 0.07890" Thick, Replacement for 089 bearing
11 24 7 838 091 Blue, 52.750 mm, +0.250 mm, 0.08370" Thick, Currently available

11 24 7 838 088 Red, 53.000 mm, +0.000 mm, 0.07875" Thick, Ended
11 24 7 841 702 Red, 53.000 mm, +0.000 mm, 0.07875" Thick, Replacement for 088 bearing
11 24 7 838 090 Red, 52.750 mm, +0.250 mm, 0.08370" Thick, Currently available

Here's a photo of the old and new bearings side-by-side with part numbers shown. As seen in the photo, the bearing surfaces are quite different.

Attachment 913003

Very informative! Based on this info, if one were to use 2 Red bearings, we would gain another .00015" clearance? That would be a 15% increase?

[Yellow Snow]

Originally Posted by e92zero

Very informative! Based on this info, if one were to use 2 Red bearings, we would gain another .00015" clearance? That would be a 15% increase?

That would give .00007" extra clearance, not .00015"

[jbraslins]

Keep them coming BMRLVR! People like you who contribute in educated and concise manner are the reason why I keep coming to this otherwise marketing forum.

[PhillyNate]

Alright. I've been silent on this issue but now have some noob questions. Is this a cold engine start up issue primarily or throughout? My car is in a warm garage always NEVER tracked and is only driven about 5.5k miles a year. Is this is an issue I should be worried about? I plan on this M3 being the first car I've kept for a significant period and want it to last accordingly. I know 10w60 is a thick oil but since I'm garaged and don't track, I don't really see this as a problem. Do you?
I got enough shit to worry about( some valid and some invalid) blowing up a $25k engine shouldn't be one more thing.

[kawasaki00]

Originally Posted by PhillyNate

Alright. I've been silent on this issue but now have some noob questions. Is this a cold engine start up issue primarily or throughout? My car is in a warm garage always NEVER tracked and is only driven about 5.5k miles a year. Is this is an issue I should be worried about? I plan on this M3 being the first car I've kept for a significant period and want it to last accordingly. I know 10w60 is a thick oil but since I'm garaged and don't track, I don't really see this as a problem. Do you?
I got enough shit to worry about( some valid and some invalid) blowing up a $25k engine shouldn't be one more thing.

Because the clearance is tight is can be called a throughout issue .... but the cold start is the real issue. Although many have stated the failure rate is small relative to the cars on the road but it makes you think about it for sure. You might run forever and not have problems or you might be like a few and have been on the verge of failure at 90k or so. That one that eas posted up would not have run for another 2k miles. Everyone has to decide their fate, pull the motor, put new berings in at a set time or not worry about it and drive. Our goal here is to educate so everyone can make a decision on what is best for their own situation.

[PhillyNate]

Originally Posted by kawasaki00

Because the clearance is tight is can be called a throughout issue .... but the cold start is the real issue. Although many have stated the failure rate is small relative to the cars on the road but it makes you think about it for sure. You might run forever and not have problems or you might be like a few and have been on the verge of failure at 90k or so. That one that eas posted up would not have run for another 2k miles. Everyone has to decide their fate, pull the motor, put new berings in at a set time or not worry about it and drive. Our goal here is to educate so everyone can make a decision on what is best for their own situation.

Thank you.

[jbraslins]

Originally Posted by kawasaki00

Because the clearance is tight is can be called a throughout issue .... but the cold start is the real issue. Although many have stated the failure rate is small relative to the cars on the road but it makes you think about it for sure. You might run forever and not have problems or you might be like a few and have been on the verge of failure at 90k or so. That one that eas posted up would not have run for another 2k miles. Everyone has to decide their fate, pull the motor, put new berings in at a set time or not worry about it and drive. Our goal here is to educate so everyone can make a decision on what is best for their own situation.

If I understand things correctly, most of us will not have the $ or access to the quality shop to properly set clearance. That leaves us with simply replacing bearings to prolong the engines lifespan.

At what interval would you recommend one to do it? 50K? 75K?

Does the risk of failure (not doing anything) outweigh the risk of opening the motor and changing bearings? I assume there's always risk doing something like that.

Thanks.

[e92zero]

Originally Posted by Yellow Snow

That would give .00007" extra clearance, not .00015"

Hmm, am I understanding this incorrectly then? Here is the script from reading the Clevite paper:

"Note: Use of a dial bore gauge is always the recommended method for measuring oil clearance. Instead of measuring journal diameter and then measuring installed bearing diameter, zero the bore gauge at the actual journal diameter. When you measure bearing diameter, you’ll obtain a direct clearance reading without the need to perform math procedures, avoiding potential math mistakes."

Based on that, the clearance is the direct difference between the journal diameter and installed bearing diameter and not the radius. If that's the case, then we should gain .00015", right? Can some one confirm this math?

[Yellow Snow]

Originally Posted by e92zero

Hmm, am I understanding this incorrectly then? Here is the script from reading the Clevite paper:

"Note: Use of a dial bore gauge is always the recommended method for measuring oil clearance. Instead of measuring journal diameter and then measuring installed bearing diameter, zero the bore gauge at the actual journal diameter. When you measure bearing diameter, you’ll obtain a direct clearance reading without the need to perform math procedures, avoiding potential math mistakes."

Based on that, the clearance is the direct difference between the journal diameter and installed bearing diameter and not the radius. If that's the case, then we should gain .00015", right? Can some one confirm this math?

Yes, I misread the specs. It does give .00015" more clearance.

I think If I were replacing the bearings I would measure up the Vac coated bearings. Just because they have a .0002" coating doesn't necessarily mean they will reduce clearance by .0004". It's possible they will be exactly the same thickness as the oem bearings. Some coatings soak into the surface by the same amount as the thickness of the coating.

You will only know by actually measuring them.

[regular guy]

Originally Posted by Yellow Snow

Yes, I misread the specs. It does give .00015" more clearance.

I think If I were replacing the bearings I would measure up the Vac coated bearings. Just because they have a .0002" coating doesn't necessarily mean they will reduce clearance by .0004". It's possible they will be exactly the same thickness as the oem bearings. Some coatings soak into the surface by the same amount as the thickness of the coating.

You will only know by actually measuring them.

We should have answers on that real soon. The factory bearings I measured are being sent out next week for Calico Coating. When they get back, I will measure them again, and place them in some rods to measure clearance as well.