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I posted a way back that I had consistently more wear on all the upper shells on the driver's side than on the passenger side which I thought odd but couldn't explain. When I saw the pics above I remembered 113 stamp is the same that I have on my old bearings and then I decided to investigate a bit further and found something pretty interesting. All of my lower shells are marked 706, all of the worst upper shells from the driver's bank are also marked 706, while all the shells from passenger side bank are marked 705 and have considerably less wear... Also worth mentioning that the 113 stamp is a different die on the 705 shells. Did anyone else find this with their bearings?

932903


Bearings are in the same position in both pics.

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I know very little about the bearing manufacturing process, but I expect that these 705/706 markings might be a batch/lot number and that this perhaps shows that there was some inconsistency in the way that the bearings were made or at least in the selection process?

I'm finally nearly finished with my bearing job and did recheck the vanos pump gear lash with a lever style dial test indicator and found that the lash was identical to what I got with the plunge dial indicator, however I will admit that I have the added piece of mind that my measurement is precise and will have less worry about it when I close this thing up and run the engine for the first time. Also while the plunge indicator seems to have achieved what I needed I have to say that setting that up was way more difficult than the lever indicator. Here's a link to the vid on that if anyone is interested.

I have a question for all you oil gurus out there. (yep an oil question, everyone loves those.) Would those in the know recommend running the bearings in with a cheaper lighter viscosity oil like a 0W40 or run a 0W40 exclusively? I read on FAMS that the BE bearings were made to run with the 10W60 syrup. Finally how many kms would you run the first batch of oil before checking the filter/replacing the oil?

Thanks in advance for thoughts and comments.
 

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2008 with 86,000 miles. The "flat" parts of the bearings seem okish, but it is the edges that have quite a bit of wear and exposed copper. The wear on edges is actually more concerning since that indicates more force over less area which could set up to gouge the crank surface. In fact the wear on the leading edges indicate that there was some fore/aft movement along the axis of the crankshaft, but these are not thrust bearings. In any event this wear is unacceptable so it was the right thing to replace them preventatively. I'm sure I could have gone another 20k miles but that is foolish. I have another M5 that has 120K+ miles that I will tear into when it gets warmer again, I'm sure those are really bad.
933803

It is a bit hard to tell but in some of the close ups circled you can see the very dark areas on the edges are actually copper.

933800


933801
933802
 

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The oil pressure is highest at center of bearing and lowest at edges.

Thus hydrodynamic floating of crank at center of bearing.
Perhaps only mixed lubrication at edges where oil pressure approaches zero.

it would only be a concern if for some reason center of combustion pressure via piston pin is not aligned with center of rod bearing running surface
 

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The wear on the leading/trailing edges may be due to it also rubbing on the radius or chamfer. I was a bit surprised to see as much wear as I did on the end edge where the upper and lower butt up against each other. Looking back at other people's pictures in this thread, I see it is present also but hard to see since most people take their pictures at an "plan view" angle that makes it hard to see those edges. Seeing it in person, I can definitely see why excessive amounts of copper would show up in a oil analysis.
 

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Hi! 200.000km with no rod bearings change yet! Very careful starting the engine and driving till the temperature is fine. I did not know any issue about the rod bearings even when I have had problems with them twice in my 330 e46 (500.000 km) due to some low oil level (yellow warning) that I think caused the break of one RB without any other problem. As far as I have read here I am running a big risk till I change them! Thanks for the thread!!!
 

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Hi! 200.000km with no rod bearings change yet! Very careful starting the engine and driving till the temperature is fine. I did not know any issue about the rod bearings even when I have had problems with them twice in my 330 e46 (500.000 km) due to some low oil level (yellow warning) that I think caused the break of one RB without any other problem. As far as I have read here I am running a big risk till I change them! Thanks for the thread!!!
Same here, I’m at 125,000 miles on (I believe) original 06 rod bearings. Not planning on keeping them in though, I don’t drive the car often but I want to have them changed some time this year. No rod knock yet... “knock” on wood
 

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Same here, I’m at 125,000 miles on (I believe) original 06 rod bearings. Not planning on keeping them in though, I don’t drive the car often but I want to have them changed some time this year. No rod knock yet... “knock” on wood
good luck to you!! hope it works out! a friend of mine said those exact words in the summer, he's now shopping for an f80 M3 because his rod bearings failed
 

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For what it's worth, on the German speaking forums for the M3 and M5, they recommend the bearings being serviced every 100k kilometers (62k miles). The germans are very anal and proud of vehicle maintenance and upkeep.
 

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Hi everyone. I just bought an 08 6 speed M5. It has 137k on it. Motor was replaced under warranty at 65k. The new motor should have the tin aluminum bearings in it. I'm really curious to see what they look like after 77k. I'll be DIYing them in the next month. I have selected +.001 ACL bearings and ARP bolts. I'll post my findings when I get to it.
 

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Not a pic of my bearings but my last BS report. Neal is the owner of OMS.

BE bearings

A0401A5B-CD03-4043-BDCD-F83E8A097132.png
8EF34552-06B6-40F1-A4FB-0E16765074B7.png
 

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I'll play along. I did BS to make sure oil was good at 10k miles, hence the TBN analysis. Castrol TWS used for about 14 months from Sep/18 thru end of Oct/19 (including Chicago winters brrrr that thick TWS boo).

935305
 

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@Fiftytwoeighty I'm sure it's buried within the 50+ pages of this thread, but are you running 10W60 on these bearings or have you taken the 0W40 approach like some others?
This is what broken-in OEM rod bearings look like after 60,000 miles of hard driving, but never put away wet. I thought I’d start a separate thread on my latest rod bearing journey. You can run 10w60 motorcycle oil, if you know how to drive this engine.



This is also a big middle finger to all the FU-Tube s85 “Top Five Things I Hate” experts. These cars are only as good as the previous owner commitment (financial) to the health of this platform. Think about this parallel with your own health. What would happen if you didn’t go to the dentist in 5 years, or 10 years? Your mouth would be all jacked up, if you only brushed and flossed. Some of these cars have never been to the dentist for a deep cleaning, outside of the laughable free scheduled maintenance, which probably ended three to five years ago.

It always cracks me up, when I read a classified that states their car was “responsibly driven” and then the seller adds “never tracked!” These cars can be responsibly driven AND tracked.

This time around, I had OMS use BE bearings from FAMS. BE was not available at the time of my last replacement in 2013.

For me, it was either OEM-L (leaded) or BE. The OEM-L is traceable and well documented, while the updated 702/703 are not able to be traced with a BS report.

Running total of my bearing life:

1. OEM (leaded) 0 to 80,0000 miles.
2. OEM (leaded) 80,000 to 150,000 miles.
3. BE 150,000 to present.

I’ve driven about 120/130 of the 150,000 miles. My clutch was replaced by the previous owner at about 18,000 miles before I bought the car. My throttle actuators are original too. I have never seen my after-thought 6MT transmission overheat at the track — which was all the talk in the early years.

I also replaced both electric oil pumps, and all my VANOS related items, which lasted for 150,000 miles.

Originally, I replaced my first set at 80,000ish. They were trashed. Thread can be found here:
Rod bearings at 84,000 miles

My last BS report before this replacement:
137,000 mile update on rod bearings replaced 53,000 miles ago. Today, I'm at 142,000 miles.

Since my last replacement in 2013, I continued to follow my “normal” start-up and driving procedures — track days included. 3000 mile-ish oil interval on 10w60 Motul motorcycle oil.

I’m looking forward to another 60,000 miles.


Sent from my iPhone using Tapatalk
See above quote. 10w60 Motul Motorcycle oil.
 

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You have a motor in very good condition, minimal blow by that contaminates oil.

your oil viscosity is close to new and so is your flash point for for a type 3 synthetic

the type 5 ester that is motul always will show a higher flash point

I would never have thought an m5 driven in Chicago winters would do this well
 

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I'll play along. I did BS to make sure oil was good at 10k miles, hence the TBN analysis. Castrol TWS used for about 14 months from Sep/18 thru end of Oct/19 (including Chicago winters brrrr that thick TWS boo).
You have a motor in very good condition, minimal blow by that contaminates oil.

your oil viscosity is close to new and so is your flash point for for a type 3 synthetic

the type 5 ester that is motul always will show a higher flash point

I would never have thought an m5 driven in Chicago winters would do this well


I think fiftytwoeighty is in SoCal...
Corrected, tried doing quote on cell phone, messed up
 

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Once decided to replace the RB and with the engine opened...what would you replace too in order to avoid spend more money in a near future?
 

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Once decided to replace the RB and with the engine opened...what would you replace too in order to avoid spend more money in a near future?
I replaced the following with my RB job:

Internal high pressure vanos line
Vanos filter
Plastic guides and tensioner on the vanos and oil pump chain
Upgraded the oil squirters to the more recent design
Added a second drain plug to the oil pan
Oil pick up seals


I also took the opportunity to change the plugs and coils because I had them all out during the job. You could also check the engine mounts and replace them if they seem worn, but I didn't do that.
 
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