Yet Another 08 Rod Bearing Replacement

[hebert51]

Brief history on the car......I bought it from an independent used car lot with 43k miles. Extremely clean inside and out and a clean car fax with two previous owners.

Going into this (my first M car purchase) i was well aware of the rod bearing problems and was prepared to do the maintenance. Although i obvioulsy was hopiing my oil analysis was going to tell me it wasnt needed....lol

I got the car and put about 1500 miles on it and then took an oil sample.

Ive attached the sample as well as a few photos of the bearings worn completely down to the copper.....

[marksae]

thanks for posting that. It's good to see a Blackstone report correlated with bearing condition.

[OzCraig]

Thanks for posting Herbert.
Just an FYI - You may wish to alter some of your contact info on the PDF and re-attach it

Cheers,
Craig

[javarithms]

Originally Posted by OzCraig

Thanks for posting Herbert.
Just an FYI - You may wish to alter some of your contact info on the PDF and re-attach it

Cheers,
Craig

This.

[javarithms]

OP can you post some high resolution pictures?

[w0ady]

So keep an eye out for copper AND lead on oil analysis, thanks.

[///M Power-Belgium]

Originally Posted by javarithms

OP can you post some high resolution pictures?

No need to post high reso. pics , because they look like crap .
Good from OP for replacing the bearings , because it was about time .
Thanks for sharing the pics..

[Froglet]

Did you have any sounds coming from the engine that made you think it would be good to replace the rod bearings, or did you do it based on the report?

Thanks

[pbonsalb]

We have yet to see a set come out that looks fine. Mine looked better than yours and I had 50% more miles -- 61k, but they still showed inconsistent wear and copper along some bearing edges.

What I don't know and no one has ever elaborated on, is how much longer bearings that look like the OP's would have gone if left alone. 10k? 50k? 100k? 150k

[hebert51]

Originally Posted by Froglet

Did you have any sounds coming from the engine that made you think it would be good to replace the rod bearings, or did you do it based on the report?

Thanks

When the car was started cold......for instance after sitting in the garage for 8-12 hours...or a few days i could always hear about 3-4 knocks/taps as soon as the engine started.

After the engine was warm or driven for a few minutes the noise was gone on re-starts. This along with the oil report had me convinced that i had gained some excess bearing clearance.

Regarding the question as to how much longer they would have lasted.....
I think that is pretty hard to predict......but what i will say is that looking at the condition of these in person.....If i would have known how bad they were i wouldn not have driven it at all.

The photos arent that great but every single upper half bearing had worn through the babbit some. Three of them were showing copper...not just on the edges but in the center as well.

[Killerfish2012]

Are these bearings starting to wear? Yes. Are they done? NO. They are still thick. Worn bearings that make noise are very thin, almost like paper, and they slide in and out of the rod making the infamous ticking noises people hear. OP what did you replace them with? Clevite oem, or Clevite coated aftermarket?

[Z K]

Originally Posted by Killerfish2012

Are these bearings starting to wear? Yes. Are they done? NO. They are still thick. Worn bearings that make noise are very thin, almost like paper, and they slide in and out of the rod making the infamous ticking noises people hear. OP what did you replace them with? Clevite oem, or Clevite coated aftermarket?

Not really, I've seen rod bearings seize on BMW engines without any warning at all. Running perfectly and then it blows. Rod bearings can go very quickly.

[Killerfish2012]

Originally Posted by Z K

Not really, I've seen rod bearings seize on BMW engines without any warning at all. Running perfectly and then it blows. Rod bearings can go very quickly.

You're right. We've seen 2 engines go, with coated bearings after 5K miles.

[tdott]

While they do display some wear, they do not look that bad. There have been much worst.

Maybe the pictures aren't clear enough for me, but i'm not seeing any copper.

[squartus]

Think its just the camera, that 2nd shade of wear in the silver should be bright copper. These picks only showing it a slightly darker shade of silver which is not what the next layer is.

[Z K]

Originally Posted by squartus

Think its just the camera, that 2nd shade of wear in the silver should be bright copper. These picks only showing it a slightly darker shade of silver which is not what the next layer is.

The brown/orange color on the bearings is the copper showing.

[pbonsalb]

Originally Posted by Killerfish2012

Are these bearings starting to wear? Yes. Are they done? NO. They are still thick.

Seriously? Wear to the copper is "starting to wear?" They are "still thick" so they are good?

Spun bearings are still thick so they must still be good.

[hebert51]

Originally Posted by Killerfish2012

Are these bearings starting to wear? Yes. Are they done? NO. They are still thick. Worn bearings that make noise are very thin, almost like paper, and they slide in and out of the rod making the infamous ticking noises people hear. OP what did you replace them with? Clevite oem, or Clevite coated aftermarket?

You can believe whatever you would like.....but from what i have seen and what i know.....these bearings are DONE......would you feel comfortable running these in your car at 6-8k rpms around a race track ?

The bearing shell with babbit is rougly .078" thick......a piece of notebook paper is about .003" thick. The bearing shell ID is about 2.093", I can guarantee you that if you had .020" clearance between the rod bearing ID and the crank journal OD it would be knocking so loud you would be scared to run it......



I am not sure how much experience you guys have with hydro-dynamic bearing design but the condition of these bearings would be totally unacceptable in any piece of rotating equipment such as.....internal combustion engines, gas turbines, electric motors, steam turbines etc......


I dont know what the stock clearance was but i see this problem as mostly being caused by the babbit formula.....


The original intent of my post was just to make people aware...again....that there is a genuine concern/problem with the rod bearings in these engines. Also i want to say thank you to all who contribute here......without reading you guys post i would have never been aware of this problem and destroyed this engine

[Killerfish2012]

Originally Posted by hebert51

The original intent of my post was just to make people aware...again....that there is a genuine concern/problem with the rod bearings in these engines. Also i want to say thank you to all who contribute here......without reading you guys post i would have never been aware of this problem and destroyed this engine

Ok, so you're in camp imminent danger. The majority of S65s, are vastly approaching 100K miles, with many like myself on this forum with well over 100K. We're in a different camp. Camp confidence. We let problems find us, and not the other way around. Again for the last time, ignoring our disagreement on imminent danger for a second. With brand new rod bearings, all you did was...

1. combine new rod bearings with stretched out old rods
2. leave your main bearings untouched (main and rod bearing wear mirror each other).
3. Leave yourself to the mercy of your installation quality. i.e at least 30K miles, to know whether you're clear of any issues, like incorrect torquing specifications, or dirt under the bearings, just to name a few.

[aussiem3]

Originally Posted by hebert51

You can believe whatever you would like.....but from what i have seen and what i know.....these bearings are DONE......would you feel comfortable running these in your car at 6-8k rpms around a race track ?

The bearing shell with babbit is rougly .078" thick......a piece of notebook paper is about .003" thick. The bearing shell ID is about 2.093", I can guarantee you that if you had .020" clearance between the rod bearing ID and the crank journal OD it would be knocking so loud you would be scared to run it......



I am not sure how much experience you guys have with hydro-dynamic bearing design but the condition of these bearings would be totally unacceptable in any piece of rotating equipment such as.....internal combustion engines, gas turbines, electric motors, steam turbines etc......


I dont know what the stock clearance was but i see this problem as mostly being caused by the babbit formula.....


The original intent of my post was just to make people aware...again....that there is a genuine concern/problem with the rod bearings in these engines. Also i want to say thank you to all who contribute here......without reading you guys post i would have never been aware of this problem and destroyed this engine

No one here has the experience or knowledge to say, as to how the bearing should look after certain number of kms. Looking at the pictures posted, it looks like normal wear. That's why OP said to post high res. pictures, so people like RD, Kawasaki00 and few others can see and post their 2c.

True, BL report is showing exaggerated Lead reading, and cause for concern. But just looking at the bearings alone don't say much. So you took a precautionary measure. Only a handful of people, paranoid about the BF issue do it. Others get on with life ...

[IIAp3x]

Bearings look pretty bad... Upper halves are all damaged...

Detonation or cold start damage...?

It gets pretty hot and cold in Texas, so take your pick...

Congrats on catching it in time!

Judging by the audible sounds of these engines upon first start up in the winter time, the oil is definitely too damn thick...

Starting to think that these guys running 0w 40 are on to something...

Why isn't there a good streetable 0w 60!!

[pbonsalb]

Originally Posted by Killerfish2012

Ok, so you're in camp imminent danger. The majority of S65s, are vastly approaching 100K miles, with many like myself on this forum with well over 100K. We're in a different camp. Camp confidence. We let problems find us, and not the other way around. Again for the last time, ignoring our disagreement on imminent danger for a second. With brand new rod bearings, all you did was...

1. combine new rod bearings with stretched out old rods
2. leave your main bearings untouched (main and rod bearing wear mirror each other).
3. Leave yourself to the mercy of your install i.e at least 30K miles, to know whether you're clear of any issues, like incorrect torqueing specifications, or dirt under the bearings to name a few.

You are most likely wrong on all 3 points.