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      08-13-2022, 10:37 PM   #2619
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Quote:
Originally Posted by Davisca455 View Post
Quote:
Originally Posted by turbotko View Post
Strangely this is the first set I've done with the top bearings looking pretty ragged and the bottom bearings not so bad. It's been bugging me these last few days but all I can come with is possibly it had a blower on it at some point
All of the top bearings out of my car looked worse than the bottoms, which made sense to me.

In my mind I picture the top bearing having to deal with the explosion on the power stroke, while all the bottom bearing has to do is keep the piston from smacking the cylinder head.


Top on the left.
Pretty sure back in the day we calculated engine stress and it turns out the most rod stress is at top dead center of the exhaust stroke. This was because the piston really just wants to keep going out of the engine…

From what I recall, that is also when rod bolts are under the most stress.

We were using cubic splines to model the rotating mass. It was 20+ years ago and perhaps my memory is off.

Green-Eggs can you comment on where maximum stress occurs?

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      08-14-2022, 03:40 AM   #2620
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Coming from the bmw dealer as i told him to stop the job when i saw the damage. Need to find a good used engine now
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      08-14-2022, 06:31 AM   #2621
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Oh damn!! I am in the process of scheduling mine for the RB replacements...

Quote:
Originally Posted by lauz View Post
Uftw post, i would like to know also the reason of thoses verticales lines as, itssimilar to mine who spun a bearing…
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      08-14-2022, 07:40 PM   #2622
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Quote:
Originally Posted by Scharbag View Post
Pretty sure back in the day we calculated engine stress and it turns out the most rod stress is at top dead center of the exhaust stroke. This was because the piston really just wants to keep going out of the engine…

From what I recall, that is also when rod bolts are under the most stress.

We were using cubic splines to model the rotating mass. It was 20+ years ago and perhaps my memory is off.

Green-Eggs can you comment on where maximum stress occurs?

Cheers,

Well I’m no Green Eggs but in all my automotive training and schooling over the years we were always told that if a rod breaks it will almost always happen on at or just past TDC on the exhaust stroke as there is no compression to help the assembly change directions…makes sense to me at least if the failure was rpm related. Bending/breaking a rod from too much combustion pressure is a different story.

As I said I’ve only done a few sets of S65 bearings myself so maybe the upper bearing wear is normal idk, still with the way this car is modded along with a few other hints around the engine I’m sticking with my theory of it having a blower on it at some point. No worries for me as all of the bores looked great as did everything else in the engine. Some new BE bearings in it now and it’s seen 8400rpm multiple times everyday for the past couple weeks. No problems yet ����
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      08-14-2022, 08:21 PM   #2623
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Quote:
Originally Posted by turbotko View Post
Quote:
Originally Posted by Scharbag View Post
Pretty sure back in the day we calculated engine stress and it turns out the most rod stress is at top dead center of the exhaust stroke. This was because the piston really just wants to keep going out of the engine…

From what I recall, that is also when rod bolts are under the most stress.

We were using cubic splines to model the rotating mass. It was 20+ years ago and perhaps my memory is off.

Green-Eggs can you comment on where maximum stress occurs?

Cheers,

Well I'm no Green Eggs but in all my automotive training and schooling over the years we were always told that if a rod breaks it will almost always happen on at or just past TDC on the exhaust stroke as there is no compression to help the assembly change directions…makes sense to me at least if the failure was rpm related. Bending/breaking a rod from too much combustion pressure is a different story.

As I said I've only done a few sets of S65 bearings myself so maybe the upper bearing wear is normal idk, still with the way this car is modded along with a few other hints around the engine I'm sticking with my theory of it having a blower on it at some point. No worries for me as all of the bores looked great as did everything else in the engine. Some new BE bearings in it now and it's seen 8400rpm multiple times everyday for the past couple weeks. No problems yet ����
It wouldn't surprise me at all if most rod failures were when they were experiencing tension, rather than compressive forces.

I imagine that on the power stroke, the connecting rod is smashing down onto the crank journal, so the rod is experiencing compressive forces.
On the exhaust stroke the inertia of the piston is yanking on the rod as it turns around at the top, putting the rod assembly in tension.
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      08-16-2022, 01:56 PM   #2624
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What he said ^
AFAIK combustion is the most strain for the bearings, exhaust stroke (nr TDC) for the rod.

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Originally Posted by lauz View Post
Uftw post, i would like to know also the reason of those vertical lines as, it's similar to mine who spun a bearing…
Vertical lines? Assuming you're referring to the photo you posted, do you mean the lines going across [edit, as in parallel to] the shell? If so that's where there's been metal to metal contact and scoring.

Quote:
Originally Posted by turbotko View Post
I can add one other interesting thing to this thread. My 2010 E90 had WPC coated bearings and ARP bolts put in it 50-60K miles ago before I owned it. Of course the first thing I did was do them again myself with BE stuff but have pics of what WPC coated bearings look like after 50k miles. I know the previous owner of my E90 and was the only tech allowed to work on it for the 5-6 years he owned it. I know he maintained it religiously including oil analysis (he insisted) and drove the car mildly. It always got the BMW 10-60W oil and filter done by me every 7500 miles.
From one tech to another, hi! (not BM though).
Excellent photos, and thank you very much for posting pulled aftermarket bearings photos, they are nearly as rare as hens teeth! That now puts the total of my aftermarket bearings photo list at just 10.

And re the different bearing wear top and bottom, yes that's normal for the lead/copper bearings, and generally the alu/tin ones fair somewhat better (although not normal wear) and can show minimal difference between top and bottom. I say this based only at looking at about 500 different photos (roughly 1/2 of them from this thread), I've not done them myself. The only ones I've done myself are on my own car (pb/cu type), and they were in a very poor state, the tops ones were all showing copper, with 2 showing purple overheating streaks! Photos here if you're
interested.
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Does oil analysis work for finding wearing rod bearings? Collation of oil analysis reports with some rod bearing photos for the M3's S65.

Last edited by Assimilator1; 08-17-2022 at 12:40 PM..
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      08-16-2022, 06:33 PM   #2625
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Quote:
Originally Posted by lauz View Post
Uftw post, i would like to know also the reason of thoses verticales lines as, itssimilar to mine who spun a bearingÖ
I think you're referring to "particle streaks." A particle streak is when a small piece of dirt, sand, or piece of metal gets in the oil stream, past the filter, and comes out through the oil galley to the rod bearing journals. It scores the bearing. If the bearing is embeddable, like original 088/089 shells, or BE Bearings shells, then it might scratch the bearing a little, but save the journal. For the later 702/703 shells, I don't think they're embeddable. Instead, they have micro grooves in the surface that is supposed to channel the particles out. The end result is probably the same, with no damage to the journal.

If you point me to a specific picture, then I'll let you know if it's a particle streak or not.
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      08-17-2022, 01:06 PM   #2626
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Hmm, I'd have to disagree that the later tin/alu (702/703) bearings don't have an embeddable layer, the tin/alu layer is the embeddable layer. That said, it is harder than lead.

From "Engine Bearing materials By Dr. Dmitri Kopeliovich" of King bearings, talking about their bi-metal tin/alu bearings.

The second layer is the bearing lining. It is relatively thick. Its thickness is about 0.012". Large thickness of the lining is very important feature of bi-metal bearings. It allows accommodation of great misallignments and other geometry irregularities. It also provide good embedability for both large and small foreign particles.
Commonly the lining is made of an aluminum alloy containing 6-20% of tin.
Tin serves as a solid lubricant and provides anti-friction properties (compatibility, conformability, embedability).


*************************************

On a separate note, perhaps the following information (from the same paper) explains why the tin/alu bearings generally fare less worse in the S65s than the lead/copper ones (both with the inadequate OEM clearances).

The third layer is the lead based overlay (or babbitt) applied over the intermediate layer.
The lead based alloy contains about 10% of tin enhancing its corrosion resistance and few percents of copper increasing the overlay strength. Thickness of the overlay is only 0.0005-0.0008". The low overlay thickness of tri-metal bearings limits their anti-friction properties like seizure resistance, conformability and embedability. When the thin overlay is removed (even partially) the anti-friction properties drop dramatically.
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Does oil analysis work for finding wearing rod bearings? Collation of oil analysis reports with some rod bearing photos for the M3's S65.

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      08-17-2022, 01:40 PM   #2627
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Quote:
Originally Posted by Assimilator1 View Post
Hmm, I'd have to disagree that the later tin/alu (702/703) bearings don't have an embeddable layer, the tin/alu layer is the embeddable layer. That said, it is harder than lead.

From "Engine Bearing materials By Dr. Dmitri Kopeliovich" of King bearings, talking about their bi-metal tin/alu bearings.

The second layer is the bearing lining. It is relatively thick. Its thickness is about 0.012". Large thickness of the lining is very important feature of bi-metal bearings. It allows accommodation of great misallignments and other geometry irregularities. It also provide good embedability for both large and small foreign particles.
Commonly the lining is made of an aluminum alloy containing 6-20% of tin.
Tin serves as a solid lubricant and provides anti-friction properties (compatibility, conformability, embedability).


*************************************

On a separate note, perhaps the following information (from the same paper) explains why the tin/alu bearings generally fare less worse in the S65s than the lead/copper ones (both with the inadequate OEM clearances).

The third layer is the lead based overlay (or babbitt) applied over the intermediate layer.
The lead based alloy contains about 10% of tin enhancing its corrosion resistance and few percents of copper increasing the overlay strength. Thickness of the overlay is only 0.0005-0.0008". The low overlay thickness of tri-metal bearings limits their anti-friction properties like seizure resistance, conformability and embedability. When the thin overlay is removed (even partially) the anti-friction properties drop dramatically.
BTW, the 702/703 bearings are tri-metal, not bi-metal as the quote above. They are from Glyco, not King. My info about embeddability and the micro grooves came directly from Glyco. I can only repeat what they said, I can't vouch for it.
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      08-17-2022, 02:56 PM   #2628
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Yea I know the 702/703 bearings are Glyco, not King, I was using their information as general over view of Alu bi and tri-metal etc bearings.

Interesting that the 702/703 are tri-metal, that negates my 2nd point.
But nonetheless, the 702/703 still has an embedding layer AFAIK, I don't recall reading in their literature about a bearing without it, even the one which mentioned the micro grooves (although I can't remember where I read the latter, and I only partially read it tonight).
Is it in the Glyco "Bearings Technical Manual"?
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      08-17-2022, 03:49 PM   #2629
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AFAIK it's not about embeddable vs. not embeddable; it's about more vs. less embeddable. The aluminum alloys are embeddable, but not as embeddable as the lead alloys.
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      08-17-2022, 04:21 PM   #2630
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Quote:
Originally Posted by Assimilator1 View Post
Yea I know the 702/703 bearings are Glyco, not King, I was using their information as general over view of Alu bi and tri-metal etc bearings.

Interesting that the 702/703 are tri-metal, that negates my 2nd point.
But nonetheless, the 702/703 still has an embedding layer AFAIK, I don't recall reading in their literature about a bearing without it, even the one which mentioned the micro grooves (although I can't remember where I read the latter, and I only partially read it tonight).
Is it in the Glyco "Bearings Technical Manual"?
Quote:
Originally Posted by IamFODI View Post
AFAIK it's not about embeddable vs. not embeddable; it's about more vs. less embeddable. The aluminum alloys are embeddable, but not as embeddable as the lead alloys.
And all of this is just an academic discussion which attempted to answer a question: what is causing the wear lines on the bearing shells. I don't think that answer has changed: particle streaks.
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      08-20-2022, 05:10 AM   #2631
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True, but you did say "I don't think they're embeddable", I was just addressing that .
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      08-21-2022, 12:03 AM   #2632
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True, but you did say "I don't think they're embeddable", I was just addressing that .
Well, it is all relative.

IIRC, lead based Babbitt is a far superior material for both conformity and embedment. Given the relative hardness of the crank, both lead and tin are embed-able. That said, one is better than the other for high RPM engines. Unfortunately, EU rules forced a change.

Alas, let us not get lost in the weeds. Bottom line, the best Babbitt material will still fail if a proper hydrodynamic wedge is not maintained.
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      08-22-2022, 01:47 PM   #2633
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Yep, agreed!
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      08-22-2022, 04:03 PM   #2634
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Mine after 118000 km
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      08-23-2022, 02:08 PM   #2635
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What year is your car?
And have you got a bigger photo of them?
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      08-23-2022, 03:58 PM   #2636
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Figured I'd chime in. Second owner of a sparkling graphite metallic e93 M3. First owner was my father in law and he babied this thing. Every single service was done at a BMW stealership. Won't ever be going back to them in the future.

Malek at MRF Did the job for me second week after ownership. Told me some of the worst he has recently seen and I maybe had 100 miles tops before something bad happened. One bearing he had to actually pry it off.

He also did a few other things and I must compliment him on his work. Car seems to be running fantastic and I'm no longer paranoid about the RBs.

97k miles
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      08-24-2022, 04:30 AM   #2637
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Originally Posted by Yorksdsu View Post
Figured I'd chime in. Second owner of a sparkling graphite metallic e93 M3. First owner was my father in law and he babied this thing. Every single service was done at a BMW stealership. Won't ever be going back to them in the future.

Malek at MRF Did the job for me second week after ownership. Told me some of the worst he has recently seen and I maybe had 100 miles tops before something bad happened. One bearing he had to actually pry it off.

He also did a few other things and I must compliment him on his work. Car seems to be running fantastic and I'm no longer paranoid about the RBs.

97k miles
Wow, had to pry one off, not a minute too early then. Great S65 save!
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      08-24-2022, 01:22 PM   #2638
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Originally Posted by Yorksdsu View Post
Figured I'd chime in. Second owner of a sparkling graphite metallic e93 M3. First owner was my father in law and he babied this thing. Every single service was done at a BMW stealership. Won't ever be going back to them in the future.

Malek at MRF Did the job for me second week after ownership. Told me some of the worst he has recently seen and I maybe had 100 miles tops before something bad happened. One bearing he had to actually pry it off.

He also did a few other things and I must compliment him on his work. Car seems to be running fantastic and I'm no longer paranoid about the RBs.

97k miles
Very similar knowledge of the prior use of my car.

I believed the S65 rod bearing issue was likely just an internet hoax, but these types of pictures are why I decided to change my RBs.

My bearings looked very similar to yours with only 55k miles.

I was glad I succumbed to the "Rod Bearing Scare".
I also sleep much better.

Good for you having that work performed, and for sharing the pics.
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      08-24-2022, 04:33 PM   #2639
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Quote:
Originally Posted by Yorksdsu View Post
Figured I'd chime in. Second owner of a sparkling graphite metallic e93 M3. First owner was my father in law and he babied this thing. Every single service was done at a BMW stealership. Won't ever be going back to them in the future.

Malek at MRF Did the job for me second week after ownership. Told me some of the worst he has recently seen and I maybe had 100 miles tops before something bad happened. One bearing he had to actually pry it off.

He also did a few other things and I must compliment him on his work. Car seems to be running fantastic and I'm no longer paranoid about the RBs.

97k miles
Yikes! That was close!
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      08-26-2022, 07:50 PM   #2640
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Wow!!! Those bad boys were toast!!! I really was a bit squeamish (spelling?) as to what I would find when I did the ones on my 08 E92 and was thinking oh wow what a save. As mentioned I don't abuse the car but as soon as that oil needle is vertical I usually can't help myself....everyday. So figured the ones I pulled out wouldn't have lasted another week. But after seeing some of these I'm now thinking they weren't so bad.

It's strange to me after being a BMW tech at the same dealer for 20 years now I've yet to see and S65 brought in with a RB failure in our shop. I've done plenty of S65 engines but usually either for hydraulic lock (normally just water) or the one I did with a blower that had a quarter size hole in number 7 sleeve. Car was sold used to a customer from another dealer with the blower installed and it blew up the next day. Anyone wanna guess what octane fuel most dealers put in EVERY single car they sell? Rarely does a sales manager or general manager at any dealership know or care what octane even is or does. Something worth remembering when buying a car from any dealer....it probably has regular gas in it.
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