Rod bearings look like poop - 85k ESS-Supercharged

[bvrider1]

I picked up an 08 supercharged M3 and some goodies this spring. I sent in oil report once I got the car back home. It's winter and I was planning on doing the rod bearings and went with ARP bolts and wpc coated bearings. With the help of many member's tutorials and feedback I was able to do mine. I wanted to contribute to the site so other's can learn too. As you can see I needed to replace these bearings.

Enjoy the pics!!!!!

Oil Report performed at 77K when I got home, Current miles is 84k when the bearings were pulled out.



Toasted Motor mounts



1-5



5-8



All

[Doc Oc]

Conclusive evidence that oil reports can be very effective.

[Harrry]

Originally Posted by Doc Oc

Conclusive evidence that oil reports can be very effective.

100%... about to send mine in.

[admranger]

Originally Posted by Doc Oc

Conclusive evidence that oil reports can be very effective.

Right up until the bearing material change, then they became much less effective (though I still do them).

[CHE///MIST3]

I wonder if oil reports stop showing lead once the most prone-to-wear spots of the bearings have lost as much lead and copper as the tolerance allows...

GM

[Harrry]

Stupid question but what level of lead would be acceptable on an oil report?

[Datka]

Originally Posted by Harrry

Stupid question but what level of lead would be acceptable on an oil report?

8

[Spoolin1]

Increases in copper and lead are probably the two that should be watched the closest, no?

[deansbimmer]

Originally Posted by GMCHEM83

I wonder if oil reports stop showing lead once the most prone-to-wear spots of the bearings have lost as much lead and copper as the tolerance allows...

GM

Although thats a very unlikely scenario, if the crank wore all the way through the lead and copper to the steel substrate, then you'd probably hear some knocking and the bearing would gall/seize and spin right after. You wouldn't stop seeing copper or lead. The engine would fail first.

OP: Great job on the preventative maintenance. I know you're relaxing after a job well done, but with rod bearings in that kind of shape I would highly advise looking at the main bearings. If there is any lead or copper in the next report then consider them ticking time bombs.

[Mvy]

Looks like the original owner didn't change bearings before supercharging. That's foolish in my opinion.

[Rat3d ///M]

Originally Posted by Mvy

Looks like the original owner didn't change bearings before supercharging. That's foolish in my opinion.

Looks like he didn't change the oil too often either.

And changing bearings before supercharging isn't a must.

[Mvy]

Originally Posted by Rat3d ///M

And changing bearings before supercharging isn't a must.

I have to disagree with this statement. Why would you put a ton of money into your car with a supercharger and all the fixings and not change the bearings? All the major SC builders recommend this. And considering the german lottery, it makes a lot of sense to be sure things are in order before you put so much extra stress on the low end.

[Rajmun340]

Originally Posted by deansbimmer

Although thats a very unlikely scenario, if the crank wore all the way through the lead and copper to the steel substrate, then you'd probably hear some knocking and the bearing would gall/seize and spin right after. You wouldn't stop seeing copper or lead. The engine would fail first.

OP: Great job on the preventative maintenance. I know you're relaxing after a job well done, but with rod bearings in that kind of shape I would highly advise looking at the main bearings. If there is any lead or copper in the next report then consider them ticking time bombs.

replacing main bearings is not a DIY it's more involved. Besides all what he did is to make himself feel better. There is no evidence that this type of bearing wear correlates with engine failure at all, the link only exist in people's mind not in reality. Each engine crank will leave its own footprint on the bearings. This is why the wear is not homogeneous from one bearing to the next. In other words he paid $$$ for a big placebo. The reason for this abnormal bearing wear is BMW design removed too much mass from the crankshaft and it vibrates and distorts too much.

[deansbimmer]

Originally Posted by JoeM3SSII

replacing main bearings is not a DIY it's more involved. Besides all what he did is to make himself feel better. There is no evidence that this type of bearing wear correlates with engine failure at all, the link only exist in people's mind not in reality. Each engine crank will leave its own footprint on the bearings. This is why the wear is not homogeneous from one bearing to the next. In other words he paid $$$ for a big placebo. The reason for this abnormal bearing wear is BMW design removed too much mass from the crankshaft and it vibrates and distorts too much.

So let me understand... Your opinion is that these bearings didn't need to be replaced and the owner wasted his money on a "placebo" service?

Also, it's an almost universally held understanding that the S65's bearing wear is due to low and inconsistent bearing clearances, but you believe it's actually due to a lower mass crankshaft design and resulting distortion? Where is the evidence and documentation for that school of thought?

I have observed first hand bearing wear similar to that of the first post in dozens of S65's that I've serviced, upgraded, or dismantled. The bearings worn that far into the copper were either next to other bearings that seized, or were present in engines with main bearing seizure. So to call the service an unnecessary placebo cure or to dismiss the mains based on an unfounded belief seems quite foolish when so much documented evidence suggests otherwise.

[pbonsalb]

Originally Posted by JoeM3SSII

The reason for this abnormal bearing wear is BMW design removed too much mass from the crankshaft and it vibrates and distorts too much.

Interesting theory. Had not read that one before. BMW changed the crank about 3 times on the S65. They all weigh different amounts, with a 10% maximum variation -- 41 to 45 lbs.

http://wiki.rcollins.org/core/index....S65_Crankshaft

So the S65 with the heaviest one should have the fewest rod bearing issues?

[BMRLVR]

Originally Posted by JoeM3SSII

replacing main bearings is not a DIY it's more involved. Besides all what he did is to make himself feel better. There is no evidence that this type of bearing wear correlates with engine failure at all, the link only exist in people's mind not in reality. Each engine crank will leave its own footprint on the bearings. This is why the wear is not homogeneous from one bearing to the next. In other words he paid $$$ for a big placebo. The reason for this abnormal bearing wear is BMW design removed too much mass from the crankshaft and it vibrates and distorts too much.

The reason for the bearing wear is inconsistent sizes from journal to journal. If you look at bearing pairs 1 and 5, 2 and 6, 3 and 7 and 4 and 8 you will notice they have somewhat similar wear patterns, this is due to the pairs on the larger journals having less clearance. One thing that has been shown is that BMW S65 Rod big end bores are fairly consistently sized, however crank journals tend to show more variance. My theory is that the tightest clearances (biggest journals) produced the worse looking bearings.

[whats77inaname]

Originally Posted by Mvy

I have to disagree with this statement. Why would you put a ton of money into your car with a supercharger and all the fixings and not change the bearings? All the major SC builders recommend this. And considering the german lottery, it makes a lot of sense to be sure things are in order before you put so much extra stress on the low end.

Technically, you're incorrect. The companies producing superchargers recommend bearing changes on 08s only. Although I do agree with your position that an ounce of prevention equals a pound of cure.

[pbonsalb]

Are you sure bearing changes are recommended for 08 models only?

[///M Power-Belgium]

Originally Posted by pbonsalb

Are you sure bearing changes are recommended for 08 models only?

Negative .

[drrust]

In examining the surfaces of the bearings pulled from my 09 at 109K miles, there were variable amounts of wear between the different cylinders. This variation may have several different causes: crank deflection, block alignment, rod deflection, ... (I really don't know, but my point is that there could be multiple causes.)

Bearings with isolated spots seemed to have "pull out" that is an abrupt change between the two different surfaces. In the OP's pics similar to areas on the bottom halves of several cylinders. If one refers to Clevites' failure guide, it may indicate surface fatigue. This may be why BMW switched bearing types.

http://www.wilmink.nl/Clevite/Clevit..._tech_info.pdf

Although there have been many pictures of worn bearings, there has not been a detailed failure analysis of the surfaces. Neither has there been any finite element modeling published of the S65/S85 rod bearings. From what I could glean from published literature of a generic rod/crank system, the stiffness of the rod also plays a role. I'm sure BMW has done this as well as their suppliers. However as nobody will ever admit to an error, I doubt that they will be made public.

I'm not sure what is considered an expected motor life, 150K, 200K or longer. Conversely some race motors are expected to have considerably shorter lives. My hope is that changing the rod bearings will extend the life to ~200K.

One additional wrench go throw in. Do the Germans still have beer dispensing machines in their factories?

[Rat3d ///M]

Originally Posted by Mvy

Why would you put a ton of money into your car with a supercharger and all the fixings and not change the bearings?

Because I think it's an overblown issue that isn't nearly as common as people make it out to be

The 550 kit is low boost and adds very little extra strain to the engine. You aren't much more likely (if any more likely) to spin a bearing with a 550 kit than with a 100% stock car. I wouldn't do a pointless rod bearing change without an ESS kit, why would I do one with an ESS kit? But that's just the difference between me and a lot of other people. I don't buy into all the hysteria.

[monterey]

Doesn't a bearing need to disintegrate to cause problems?