S65 Oil reports collation - does oil analysis work for tracking bearing wear?

Davisca455 wrote

Scharbag wrote

Davisca455 wrote

Not an opinion, but an observation/question.
In an earlier post in this thread, it seemed like it was stated that the bearing tang was only for installation purposes?
Not sure if that is what was meant, so it generated the next question.
I get that they have to be installed correctly, and that tang to slot helps us do this, but when I looked at the rods, caps and bearing/tangs as an assembly, it looked to me that tangs serve more purpose than just installation of the bearing?
It looks like they are the only location feature to limit lateral movement along the axis of rotation, and the tang also seems to be the only feature that would prevent rotation of the two shells once the connecting rod/cap are assembled?
Or is there some other more subtle thing going on that I don't yet understand?

There are lots of tangless bearings out there. The tang does nothing but help installation.

Once the rod cap is tightened, the bearing is held in place by that force. As it has been said, 10 pounds of stuff in a 5 pound sack is an apt way to describe it.

Cheers,

Ahh, that makes sense, so the bearing shell assembly has a slight interference fit with the connecting rod assembly once everything is clamped up.

Yup. She is squished in there real tight. This is where rod bolt strength and stretch comes into play with bearing eccentricity.

A lot of really precise nerdy sh!t going on in there.

Lol, yep!

New case added of OA didn't showing any bearing problems where their clearly was.
The earlier poster Davisca455 added, (thanks for the PM btw ).

First - hats off to the compilation, and adding the link to your signature in your posts; caught my eye right away as I am considering changing my rod bearings (2011 LCI, currently @ 55k miles, still on original RB, but never tracked or auto-crossed, and never let RPM > 2k until oil temp reaches mid point).

Mr. Miller (Roundel) gave a suggestion to a place to do it in the north-east, and so I will probably do it as a preventive maintenance in a few months. But I digress.

Saw this nice recent video on a recent RB change @ Performance Dynamics (west coast shop) on a 2013 that had 30k miles.

Video also dwells a bit into how the previous RBs were vs. the later ones, and if oil analysis can be helpful.

Plus, the youtube poster is offering a group buy/discount for those interested. Nice effort by that person.

So, hope it is useful.

Added 2 new cases, Brap M and InnerBlueSkies, 1 showing OA worked for them, 1 showing it didn't.

BimmerRules!
Thanks , I hope people are finding it useful.
Just watched that video.

For anyone who wants to watch that video, most of the 1st 2 mins is the guys showing off his car (which is nice to be fair ), the bearings are shown at 2:17, they are quite worn but not terrible (for S65), typical for LCI bearings, although they have only done 31k miles. The oil analysis discussion starts at 3:25
Interesting video, but their are lots of mistakes he makes (which I commented there for anyone who cares).

Added my case to the list, the single oil test I had done shortly prior to the bearing change showed no sign of trouble.

Looks like there's a new case of an engine blowing not long after a good oil report. kmberger8's engine grenaded itself recently causing a lot of damage

I just need to find out the mileage interval between the oil report and it blowing up, before adding it to my 'missed' list.