This doesn't look good, was this the worst looking one?

 

I only pulled #10 as I'm going to R/R as I move up the crank. 9 more to go, waiting on parts.

 

I gotta stop reading this board... all these rod bearing posts are getting me paranoid (glad you found out about it before it went though!)

 

That is bad!

 

Was there much play in it?

 

None, very tight. If you move your finger over the worn part, you'd never know it. Very smooth. This is why I'm doing it early. Keeping my fingers crossed on the other 9. I guess I'll do it again at 100K.


I want to thank a few people as I really researched and asked a lot of questions before I dove into this. Vincent at Bimmerzone got all my parts and was a great help. Duschanio and GJS also helped answering a lot questions that l PM'ed them with. Thanks for that. I will post more pictures and the other bearings.

 

how long did it take you to get to the bearings?

 

I took my time and had the top done yesterday. Lifted it this morning and it probably took 3 hours to finally get the pan off. The pan bolts are a very slow process. Put the pan bolts in holes on a piece of cardboard with a drawing of the shape of the pan so I wouldn't mix them up. There are a bunch of different size bolts all the way around the pan. I'll post more pics tomorrow.

 

Thanks a lot for taking the time to document all of your work!

Out of curiosity what is your oil change interval, do you use TWS, and how many miles have you owned the car for?

Thanks again:applause:

 

Thanks a lot for taking the time to document all of your work!

Out of curiosity what is your oil change interval, do you use TWS, and how many miles have you owned the car for?

Thanks again:applause:

I am the second owner. Bought it from the BMW dealer that sold it new. I have all maintenance records and I'm sure it hasn't been tracked. It was very pristine when I bought it at 40k. I have done 2 oil changes and now use LM. It has the original clutch in it and that part has been perfect. Compression is great, all near 140. I have a new FW and clutch in the garage waiting but the thing runs perfect. My UOA showed 8 parts lead where the universal average is 13. I sent another sample in today when I drained the oil. There was no hint that showed bearing wear. I just did it because half the fun for me owning the car for me is working on it. I got nervous seeing what had happen so for a few hundred dollars, I decided to take a look. We need this process documented. To me letting it go too far was no option so I had to take a look.

Here are the pan bolts. If you don't keep track, it can get out of hand fast. I bagged and tagged all other bolts for the different components.

 

You will be well versed just in time to do mine.

BTW, how much was the vanos hose?

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Wow! Thanks for sharing.

My 84,000 mile Beast is with my Indy now. Work is scheduled to start on Monday. I'm really glad I decided to do the bearings.

 

Hmm maybe just like the S62 engine? Most likely #10 will be the worst. It's furthest away from the oil pump.. I'll be checking in on this thread to see if my theory is correct? (Just browsing doing research as an E60 or E63 purchase is in my future LOL)

Lol! Gotta admit, some of my techs at my dealer do this. But a majority of the ones label them or organize them in some way to know where they go during reassembly.


I got 48k miles on my car and this has got me scratching my head. I don't know if I should go digging in and replacing my rod bearings now.. My oil analysis's have been fairly low in lead particles. But than again so were the OP's. This seems like such low mileage to be doing something of this extent? Of course I would rather be safe than sorry.

I see you're in DFW area, which dealer do these techs work at? I'd like them to do the work on my car!

If your motor was broken in properly and you wait for the oil to be at full operating temp before hammering it I think your bearings should be good to 100K, and use the correct oil. I've seen a few S85's around now with well over 100K miles still running fine.

 

Man I wish I had the resources and know-how on how to do this. Too bad I'd have to take it to a shop and pay mucho dinero just to even check.


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Man I wish I had the resources and know-how on how to do this. Too bad I'd have to take it to a shop and pay mucho dinero just to even check.


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Only way to check surely I know it to take it apart and get your hands on them physically for looseness, or just pull the caps and inspect. If your shop has it that far apart they might as well put new shells in while they're there, the shells very cheap compared to the labor. Just to inspect they'll be charging you 90% of the cost just to change them.

 

Here are more pictures that I promised. Finally got the computer to recognize the memory card. I don't know how to put comments next to each picture. One picture has the vanos pump out and you can see the braided line I'm going to replace. One picture you can see the suspension lowered and how much room there is to remove the pan.

 

Great job! Just put my lift in, but didn't want this to be my first job! That is an ugly looking bearing for 50k of "regular" service. Looking forward to the rest of the pics. I have 64k on the clock and need some Valium.

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I'm hoping that since #10 is furthest from the oil pump, it's the worst one. I won't get back to it until Monday.

 

the S85 V10 has what is called "fracture-split forged powdered metal connecting rods". These rods shrink after extended use from heat. Which means as they shrink ~ they put a tighter and tighter grip on the crank journal. This causes you to have unequal wear on the rod bearing as seen in this pic. It is a poor design... actually a terrible design.

I have taken apart eleven of this in the past month & have sold over 35 S85 in four months. Every one of these motors will do this at a certain mileage. Some quicker than others depending on driving habits and maintenance schedules. The only way around this is to change the rods.

OP: I hope you are not putting back in the stock rods. If so, it will blow up within a few thousand miles. pm me if you want details. or email me. troyjeup at hotmail. kinggf

 

the S85 V10 has what is called "fracture-split forged powdered metal connecting rods". These rods shrink after extended use from heat. Which means as they shrink ~ they put a tighter and tighter grip on the crank journal. This causes you to have unequal wear on the rod bearing as seen in this pic. It is a poor design... actually a terrible design.

As if we didn't have enough to worry about! I did a quick look around and it seems this type of con rod is being widely used because it is cheaper to make. That is disturbing by itself to read as a consideration for a part selected to use in a high-performance engine. I saw nothing about age-related shrinkage being an issue, but fatigue life may be somewhat lower than a comparable conventional forged rod. Metal fatigue could lead to distortion and bearing wear issues or catastrophic rod failure. Below is an excerpt of one study.

"During compacting, trapped oxygen in the powder results in porosity, decarb, and oxide penetration.
The density can vary within powder metal connecting rod.
Costly part density modification or infiltration is required to prevent powder metal defect.
From tensile tests and monotonic curves it is concluded that forged steel is considerably stronger than the powder metal.
Yield strength of forged steel is 19% higher than that for the powder metal. Ultimate tensile strength of forged steel is 8% higher than that for the powder metal.
Better fatigue resistance of the forged steel material, as compared with the powder metal material was observed.
Based on strain-life fatigue behavior, the forged steel provides about a factor of 7.
longer life than the powder metal in the high cycle regime.
Fatigue limit (Nf = 106 ) for powder metal is 79% of that for the forged steel."

Here is a link to another study: Study Confirms Forged Crackable Steel Connecting Rods Cost Less and Perform Better Than Forged Powder Metal Rods

I don't know for a fact that S85 rods are forged powder, has anyone else confirmed this?:dunno:

 

I haven't pulled the motor, just rod bearings from the bottom. I have only pulled #10. My new bearings just showed up and was going to put in new oem bearings and new oem rod bolts. Tell me what you know, I'm all ears.
Bill

 

Here's a great article for those interested ...

http://www.eng.utoledo.edu/mime/fac...du/mime/faculty_staff/faculty/afatemi/papers/2004SAEAfzalFatemi2004-01-1529.pdf




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From the "BMW Technical Training: E60 M5 Complete Vehical" manual

"The connecting rods are forged steel and use the 'cracked' configuration on the 'big end.' For weight reduction, the small end of the connecting rod is trapezoidal and uses a tapered piston pin.

The connecting rod weighs 582 gms +/- 2 gms. The rods are of an assymetric construction which allows for a narrower connecting rod. The narrower rods contribute to the overall reduction in engine length. The rods can only be installed one way. Refer to repair instructions during installation."

Clearly Jeuprx-8 has extensive experience with the S85....I am certainly not arguing with his personal observations...just offering what BMW has published about the connecting rods...

 

From the "BMW Technical Training: E60 M5 Complete Vehical" manual

"The connecting rods are forged steel and use the 'cracked' configuration on the 'big end.' For weight reduction, the small end of the connecting rod is trapezoidal and uses a tapered piston pin.

I appreciate all the knowledge and experiences being shared. This makes the forum the great resource it is.

I'd just like to confirm if the S85 rods are forged from powdered metal or steel blanks. Anyone have some confirmation on this?

The clearance issue can be checked with Plastigage during assembly. Highly recommend this if you want some peace of mind after spending all the time to change the bearings. It still leaves you wondering about out-of-roundness and cracks though. That would require pulling the heads, pistons... might as well replace the rods at that point anyway.

Personally, I'm going to change the oil at 5K intervals and run it to failure or until the warranty runs out (near 100K), then consider a complete overhaul and upgraded internals.

Why lose sleep over this or not enjoy the car because of unknowns.

 

The rods are actually very large & bulky to be honest. The first time I showed it to my race shop that Bult my ls7, they are shocked that BMW put that rod inthe s85 (it is also the same as the s65).

If you are trying to do a complete bearing swap, I strongly advise pulling the heads and having the rods sent out to be machined to be true again. The inside diameter of the rod has shrunk and needs to be opened up to the stock specs so they match the new bearings you have. If this is not done, your shrunken rods that have a smaller ID than when the motor was new ~ will squeeze on your new bearings too tightly and you will spin one of your new bearings very quickly.

Seven of nine motors I got back as cores from customers were recent rebuilds with new bearings. I am a firm believer that there is really only one way to rebuild this motor to be successful & that requires a complete teardown. Once you crack it open, there is no turning back or you will regret it unfortunately. It is the sole reason why I do not sell reman. S85. The cost to do this correctly is around $6 or $7k & that is how much I sell a perfectly fine motor for that has never been opened.

If you change the rods & put some ACL bearings in it, you will be good for 100,000-miles. The rods are the reason these are blowing up left and right, along with 15,000-mile oil change intervals.

 

Not withstanding Troy's business practices, am I the only one concerned that a bearing swap may not be the solution as some are advocating?

 

I agree Troy, one reason why I decided on a complete rebuild and not just changing out the bearings only.....especially with OEM ones again.

 

so it would be better to drive it until it blow up then rebuilt, since you have to tear the engine down anyway. maybe the best way to enjoy our beast is to stop reading the forums. ignorant sometimes is a blessing.

 

so it would be better to drive it until it blow up then rebuilt, since you have to tear the engine down anyway. maybe the best way to enjoy our beast is to stop reading the forums. ignorant sometimes is a blessing.

No as you do not want to ruin the block itself or have cylinder wall damage. Boring out the alusil material on this engine is not like any normal engine block and has to be done in a special way.....DINAN has it down but price aint cheap.

 

This would be an EPIC DIY....

 

So it looks like we agree that the problem is tight bearing clearance, some say the motor was built that way, other says rods are shrinking/deforming , eithr way = a complete engine teardown im at 41k miles, hopefully my beast last long enough till I can afford a F10 (3 more years) .

 

I'm torn now. All parts here and ready to go. I did measure the old and new bearings and the thickness is the same. I will buy and use plastigage just to see where the new ones are. The drama is building. I did throw in the new internal vanos hose last night along with the tiny filter just above the vanos pump. It sits in the block housing. The screen on the old one was all pulled or sucked in compared to the new one. I'll have pictures of that.

 

I'm torn now. All parts here and ready to go. I did measure the old and new bearings and the thickness is the same. I will buy and use plastigage just to see where the new ones are. The drama is building. I did throw in the new internal vanos hose last night along with the tiny filter just above the vanos pump. It sits in the block housing. The screen on the old one was all pulled or sucked in compared to the new one. I'll have pictures of that.

Good call on Plastigage check. Just proceed on, button it up, and relax for another 50K. There's too much speculation and not enough hard evidence of root cause to worry. I'll let you know when/if mine go wrong! :byebye:

 

Thanks, I think that's what I'll do. I just put this up on the other M3 forum where they have been having the same problem and discussion. A lot of knowledgeable people and engine builders over there. Haven't seen the connecting rod mentioned as the issue so I threw that into the mix. This will get good.

 

After you finish do you plan to still use 10w60 or has any one considered a thinner oil? 5w40 maybe?