Official S65 Rod Bearing Condition Example Thread

[Assimilator1]

Awesome! Thanks , you sure btw?

[Helmsman]

Originally Posted by Assimilator1

Awesome! Thanks , you sure btw?

Yep, I'll send it over during the week mate.

[Assimilator1]

I wonder, has anyone seen an LCI bearing break up like some of the lead/copper ones do? In the 525 I looked at I didn't find one, but their are some LCI engines in the 'blown motors' thread.....

PS FB links corrected in my photo list post (and moved one up a group).

[IamFODI]

If you want to know what a bearing is made of, the only way is through a metallurgical analysis by a competent lab.

One US-based example (pardon the website): http://www.element.com/

Anything short of that is guesswork.

[Assimilator1]

Well that would be ideal (I'm still waiting for your crowdfunding thread for that btw ), but atm all I want to do is to see what colours are shown as you go through the layers. And especially if the coppery layer stands out as it's exposed.

As for my previous post, I just wondered if anyone had seen them disintegrate.

[drrust]

Originally Posted by IamFODI

If you want to know what a bearing is made of, the only way is through a metallurgical analysis by a competent lab.

One US-based example (pardon the website): http://www.arrowlab.com/

Anything short of that is guesswork.

Automotive companies have detailed specifications for the parts they buy. One can be confident that the supplier used the same grade of steel in terms material and utilized the coating specified by BMW. I work for an automotive supplier and one must jump through many hoops and go through period audits to verify you are supplying what the specification calls for. If you want to pay for a full blown metallurgical analysis you will have to pay several thousands of dollars for all of the work entailed. Because there is a multi layered coating, cross sections would be necessary. The radius of the bearing would make some analysis methods such as Optical Emission Spectroscopy (OES) complicated as one needs a fairly flat piece. Same with Glow Discharge Spectroscopy (GDS) which can burn through the layers of the coating.

The bearing is designed to have an oil film between the two surfaces, so in theory there shouldn't be metal to metal contact. This whole thread shows that isn't the case.

[Assimilator1]

I think he knows that (oil film and expense of analysis) , he/we want to know the composition of the LCI bearings.

[JEREM3Y]

RBs replaced at 60k miles, 09 E92 M3 completely stock. Replaced with WPC Treated RBs

[Assimilator1]

Don't appear too bad (still excessive though), quite even wear at least.

Could you see any copper at the edges? (hard to see the parting line edges in that photo).

[osukf09]

Finally bit the bullet and changed RB's and motor mounts as my car just came off extended warranty.

2011 e92 M3, 100k miles on the dot

Replaced with VAC extra clearance and ARP bolts. Stayed with OE motor mounts. Originally considered BE/BE-ARP, but got tired of waiting.

Original bearings have wear, obviously, but they don't look too terrible given the mileage. The pictures actually show more contrast in color of the bearings than appeared in person. They look like many LCI bearings I've seen in this thread. Oil changes were done every 5-7k with 10w60. Motor mounts were obviously thrashed. Car feels so much better now with fresh mounts.

Thanks to Greg at Performance Dynamic down in Santa Clara for the great work and pricing.

[Contra]

2008 6MT E92 with 72k miles. Replaced at Markert Motorworks (now True Automotive) with VAC bearings and ARP bolts. Definitely worn, but not as badly as I expected.

[DRLane]

Originally Posted by Contra

2008 6MT E92 with 72k miles. Replaced at Markert Motorworks (now True Automotive) with VAC bearings and ARP bolts. Definitely worn, but not as badly as I expected.

😳 2,3,4 upper looks rough...

[Assimilator1]

Yea they are quite worn.
Contra Have you still got the original bolts to hand?

Actually, has anyone got OEM rod bolts to hand?

[Helmsman]

Originally Posted by Assimilator1

Yea they are quite worn.
Contra Have you still got the original bolts to hand?

Actually, has anyone got OEM rod bolts to hand?

Why, planning to measure the stretch mate..😉

[Contra]

Originally Posted by Assimilator1

Yea they are quite worn.
Contra Have you still got the original bolts to hand?

Actually, has anyone got OEM rod bolts to hand?

Yeah I still have the bolts. Why?

[supercleanm3]

hi, just did a replacement on con rod bearing, surprise condition was good, will update photo sooner.

After did the replacement mechanic told to drive below 3k rpm,
what is the purpose behind this?

[///M Power-Belgium]

Originally Posted by supercleanm3

hi, just did a replacement on con rod bearing, surprise condition was good, will update photo sooner.

After did the replacement mechanic told to drive below 3k rpm,
what is the purpose behind this?

Mate It's like a new wife . Drive it tender and gentle !

[Scharbag]

Originally Posted by supercleanm3

hi, just did a replacement on con rod bearing, surprise condition was good, will update photo sooner.

After did the replacement mechanic told to drive below 3k rpm,
what is the purpose behind this?

There is zero point to babying after bearings are changed. Drive it normally.

[Richbot]

More to make sure if anything shakes loose because of a mistake, it has a better chance of not being catastrophic. After a few dozen miles I'd say, hit it.

I also like to do an oil change pretty quick after any internal engine work, anytime a cylinder head or oil pan is off, but that's mostly superstition. I did a quick oil change about 300 miles after the bearings were done.

[Helmsman]

Originally Posted by supercleanm3

hi, just did a replacement on con rod bearing, surprise condition was good, will update photo sooner.

After did the replacement mechanic told to drive below 3k rpm,
what is the purpose behind this?

Pics or they're not Superclean as claimed.

[Assimilator1]

Helmsman
I finally rubbed down part of your shell today , will post pics tomorrow.
JFYI, their is a clearly visible copper layer. So it's interesting that the LCI shells rarely get there.

Originally Posted by Contra

Yeah I still have the bolts. Why?

I'm after the dimensions of the bolts, info for this thread.
I'm after UHL (length from under the head to the end of the threads), grip length (the unthreaded bit under the head) and the thread length (other dimensions are a bonus ).


Btw guys, I am aware that used OEM bolts will have stretched, but it shouldn't be much right? 0.5-1mm?? Does anyone know?

[Helmsman]

Originally Posted by Assimilator1

Helmsman
I finally rubbed down part of your shell today , will post pics tomorrow.
JFYI, their is a clearly visible copper layer. So it's interesting that the LCI shells rarely get there.

That sounds interesting, make sure you bring out the nice camera with the big zoom scope! Maybe dig up and post in Deansbimmers earlier thread with close up pictures.