\ 2008 82k miles Stock Rod Bearing Replacement /

[VF-Engineering]

Earlier this summer, by request of a local owner, we investigated the condition of the rod bearings in his 2008 DCT 82k mile, stock E90 M3 prior to installation of a supercharger system. Not knowing what we would find, our tech was prepared with a set of VAC upgraded bearings as a precaution. Below are the pictures of the condition of the bearings(!) which the owner was not too happy about. The new bearings were installed and tolerances verified before closing up the new VAC performance baffled oil pan.

It is becoming more apparent that rod bearings are a more important service item than one would expect, and wear heavily on these engines with or without supercharger enhancements.

If anyone has any Technical questions, please feel free to email us Technical@vf-engineering.com

[kawasaki00]

Thanks for the pictures and info.
Still not understanding why people do not think this is a problem. As engines get older and higher mileage I think we are going to see a heap of failures start creeping up.

[jacobe92]

My 2011 M3 had a rod bearing failure at 31,000 miles and I wasn't SC. At the time I was doing an oil change every 4 track dates or 4000 miles. I believe this Rod Bearing problem is not an inherently a high mileage M3 problem.

[Ezio]

If i had a high mile and out of warrnety S65. replacing the rod bearings is something i would be thinking about.

[Verify]

welp.. im sold. too many shown not to give it a shot.

Time to order the VAC kit and go to work

[metro44m3]

I'll be changing mine at 50,000 miles as a precautionary

[a burrito]

Could someone explain what the rod bearings should look like at 100k miles? I understand that it cannot look like new so there will be some signs of wear (scratching or some etching on the bearing) but how do you know that this is far out of tolerances? On EAS's thread, I can see that one of the bearings that they took out (#8) was obliterated since there were chunks missing off the bearing but this bearing just looks worn.. Is the answer if the bearing starts to sheer into a different color in the center, then its shot?

Can someone also explain how to prevent this or if this is purely a flaw in BMW's design.

[MilehighM3]

Since no one has pulled bearings on a car at the first oil service and every one thereafter to establish a timeline, there is no way to determine what mileage this should be done at. Especially considering these threads that have no oil analysis to back up the observation of bearing wear. Obviously those bearings are toast, but how do you know they haven't looked that way for the last 50k? How do you know whether or not they would go another 100k? Was the bottom end noisy? Was the car pulling timing or running poorly? I've pulled S54 bearings at 1200 miles during the recall days and seen them look like that. Obviously a lot of those cars were failing at the time, but it was determined to be an assembly contamination issue. I also just replaced some S54 bearings less than a month ago that were never done on an 03. The car had an HPF stage 1.5 kit installed at 56k miles and had 87k on the clock. They looked basically normal for the mileage with very little wear, especially considering the client follows the service indicator for his oil services. So we can't say all M engines running 10W-60 have issues can we?
Btw is every vendor jumping on the band wagon to start a rod bearing thread? Who's next, Gintani? Must be the cool thing to do these days. :

[DLSJ5]

The S54 is often brought up and used as an analogy, I'm curious to know what the clearances are on those bearings.

[MilehighM3]

Originally Posted by DLSJ5

The S54 is often brought up and used as an analogy, I'm curious to know what the clearances are on those bearings.

From what I remember, it's .001 like the S65

[Endless619]

Originally Posted by Bmw135er

Since no one has pulled bearings on a car at the first oil service and every one thereafter to establish a timeline, there is no way to determine what mileage this should be done at. Especially considering these threads that have no oil analysis to back up the observation of bearing wear. Obviously those bearings are toast, but how do you know they haven't looked that way for the last 50k? How do you know whether or not they would go another 100k? Was the bottom end noisy? Was the car pulling timing or running poorly? I've pulled S54 bearings at 1200 miles during the recall days and seen them look like that. Obviously a lot of those cars were failing at the time, but it was determined to be an assembly contamination issue. I also just replaced some S54 bearings less than a month ago that were never done on an 03. The car had an HPF stage 1.5 kit installed at 56k miles and had 87k on the clock. They looked basically normal for the mileage with very little wear, especially considering the client follows the service indicator for his oil services. So we can't say all M engines running 10W-60 have issues can we?
Btw is every vendor jumping on the band wagon to start a rod bearing thread? Who's next, Gintani? Must be the cool thing to do these days. :

Some good points here. I agree with you. We don't know they looked like that the last 50k miles.

[DLSJ5]

Originally Posted by Bmw135er

From what I remember, it's .001 like the S65

I didn't do a lot of digging but found that on the S54 they increased the bearings from .03 to .04 after the rod bearing issues, so that's quite a difference if true.

Edit: that's in metric, so it's not a huge difference, but still some. 03mm to .04mm is .0012 to .0016 inch.

Here's a thread discussing it back in 2002:

http://forums.bimmerforums.com/forum...amp-other-info

[1MOREMOD]

bryan is that second portion of the article true about not replacing connecting rod bolts? why would that be? i still was planning the BW kit with ARP bolts, at some point as a precautionary measure.

[MilehighM3]

Originally Posted by 1MOREMOD

bryan is that second portion of the article true about not replacing connecting rod bolts? why would that be? i still was planning the BW kit with ARP bolts, at some point as a precautionary measure.

That article was written by someone that loves to copy and paste, in 11/01. The bolts are reused on vehicles with original engines produced up to 12/02 if memory serves me correctly. They are also 11mm vs 10mm produced after that. The later production bolts have to be torqued and stretched 3 times in order to attain the proper stretched length. It is also important to reinstall them on the same side of the rod to retain the balance of the rotating assembly as well as possible.

[MilehighM3]

Originally Posted by DLSJ5

Edit: that's in metric, so it's not a huge difference, but still some. 03mm to .04mm is .0012 to .0016 inch.

Good catch with your edit. I was about to do the math for you when I decided to first finish reading your post. I like it when people post accurate information. I wonder if anyone has the S65 clearance spec down to the .0001? Adding the extra digit puts the clearance closer to .002 than .001.
On a separate note, what did you have your bearing clearance set to?

[BMRLVR]

I am not quite sure why everyone still thinks that it is acceptable to do bearings as a maintenance item!?

The thing is, when you install new bearings without removing the engine, especially coated bearings like everyone seems to be using not only are you taking clearance away due to the added thickness of the coating, but you are also not able to properly measure the journals and rods to calculate an accurate clearance for each individual bearing/journal once assembled. I do realize most mechanics are going to be using plastigauge but lets face it, plastigauge is to give you an idea of clearance and is not a substitute for proper measuring with bore gauges and micrometers.

So while I understand that the most people are not willing to remove their engines and have the cranks ground to achieve proper clearances I caution against installing coated bearings due to the added thickness and inconsistency of the coating. Calico themselves states the coating ranges from 0.0002" to 0.0004" and cautions to use their bearings with clearances of 0.002" to 0.003" and not to worry about the reduction in clearance from the coating. At 0.001" you really need to worry about 0.0002" to 0.0004" of a reduction in clearance.

If you guys want to replace your bearings because you are not interested in removing your engines, please do it with OEM bearings so that you are not rolling the clearance dice with the coated bearings. I am not too versed on the Calico coating used on the bearings, it may be great, but please remember that the main and rod bearings in an engine work on the principle of hydrodynamic lubrication and no coating can replace that. Granted the coating on the bearings may be great, but at some point the coating is going to fail and then what happens?

Just some food for thought...... The bulletin posted above shows that BMW recognized that adding clearance to the S54 would be accepted as a fix. They originally wanted the engines to be built with 0.03mm (~0.0012") of clearance but later wanted 0.04mm (~0.0016") of clearance. Both of these numbers are greater than what most of the measured S65's had for clearance (BMW don't post bearing clearances for the S65). To be honest, if the S65 had 0.0016" of clearance on the rods, although that is still a little tighter than accepted for a high performance engine, I would be comfortable with it an wouldn't be disassembling my engine to add clearance!

[1MOREMOD]

Originally Posted by Bmw135er

That article was written by someone that loves to copy and paste, in 11/01. The bolts are reused on vehicles with original engines produced up to 12/02 if memory serves me correctly. They are also 11mm vs 10mm produced after that. The later production bolts have to be torqued and stretched 3 times in order to attain the proper stretched length. It is also important to reinstall them on the same side of the rod to retain the balance of the rotating assembly as well as possible.

so then having a 10/01 build car the BW kits and others wont work for me and am left with OEM rod bearings and reusing the stock rod bearing bolts?

[BMRLVR]

Originally Posted by Malek@MRF

These are some of the most valid points posted yet in regards to this. There is no empirical data to suggest when these bearings go bad or should be replaced.

What I don't understand is, sure, we know that the tolerances are very tight, we have known this for over a decade now starting with S54's, so why are coated factory bearings being installed which reduce some of the much needed clearance. I have never been a fan of building an engine very tight (for obvious reasons).

It's claimed that this is a common problem on S65 engines, it is not a widespread issue. I would hate to see everyone diminishing their time enjoying their M3's because of constant worry over an issue which is not common.

It is very funny that you say that the issue is not common.......... Every engine that was opened so far showed excessive bearing wear for the mileage!

While many people are not having issues, they are most likely the people who have an issue but don't know about it because they haven't opened up their engines.

[MilehighM3]

Originally Posted by 1MOREMOD

so then having a 10/01 build car the BW kits and others wont work for me and am left with OEM rod bearings and reusing the stock rod bearing bolts?

I am unfamiliar with the bimmerworld (bw?) rod bolt applications. Your car is 10/01 build so you have the 11mm bolts that are reusable. So if you want rod bolts from ARP to install with your new bearings, order accordingly I guess.

[1MOREMOD]

Originally Posted by Bmw135er

I am unfamiliar with the bimmerworld (bw?) rod bolt applications. Your car is 10/01 build so you have the 10mm bolts that are reusable. So if you want rod bolts from ARP to install with your new bearings, order accordingly I guess.

other way i think the kits show m11 which im assuming is 11mm bolts for the earlier years and m10 for later. here it is.

http://store.bimmerworld.com/s54-rod...kit-p1020.aspx

[MilehighM3]

My bad. I contradicted what I had already posted with a fat finger and no proofreading.
I edited my last post, thanks for catching that.

[1MOREMOD]

Originally Posted by Bmw135er

My bad. I contradicted what I had already posted with a fat finger and no proofreading.
I edited my last post, thanks for catching that.

so i do still have an option here for my ancient car. im not in any hurry yet to do this but dont want to be hung out to dry with a spun bearing either and repairs that come with it. also dont know how much an advantage the ARP bolts and modified design of the bearing is? maybe it will be more important for me once i add the turbo, nitrous supercharger ive had my eye on. the turbo feeds exhaust boost to the SC so i can run 87 lbs of boost at max for about 1497 hp and with a 500 shot of nitrous i should be in the ballpark of those wrx-evo hard parker guys.