Official S65 Rod Bearing Condition Example Thread

I have a 2011 with 53k right now. Nice to see 2 recent examples at the same mileage, they look great as expected.

TboneS54 wrote

I have a 2011 with 53k right now. Nice to see 2 recent examples at the same mileage, they look great as expected.

Not that I’ve seen everything, but I don’t think I’ve ever seen a set of the updated bearings worn down to the copper. Tons of pics in this thread alone, and the only ones showing copper are the ones that have been sanded to find it.

FWIW, might want to check your build date. I feel like I remember hearing that some 2011s still came with leaded rod bearings.

Thanks. I have an 2011.5 so I'm good from what I remember reading, but I'll double check again.

IamFODI wrote

Not that I’ve seen everything, but I don’t think I’ve ever seen a set of the updated bearings worn down to the copper. Tons of pics in this thread alone, and the only ones showing copper are the ones that have been sanded to find it.

FWIW, might want to check your build date. I feel like I remember hearing that some 2011s still came with leaded rod bearings.

because the updated bearings are aluminum and tin, and have no copper

Tommysalami wrote

because the updated bearings are aluminum and tin, and have no copper

o boy

jvictormp wrote

o boy

Yeah, this myth is going to take quite a while to die.

2012 e92 m3

Purchased the car last month at 65k miles with no history of rod bearings. Car had 665xx miles when rod bearing service was scheduled this month.

Replaced with BE bearings and ARP bolts

So, is there a consensus yet on V2 vs V1 BE bearings? Getting ready to do this work. Thx.

Way too early to know that I think. We still only have a tiny amount of data on how BE (v1) and other aftermarket bearings fair after some use.

Tommysalami wrote

because the updated bearings are aluminium and tin, and have no copper

Incorrect.
This is a photo of a tin/alu bearing (which I've posted earlier) that I partially rubbed down with emery paper. You can clearly see the copper.
But I've yet to see one that's actually worn through to the copper during use.

Assimilator1 wrote

Way too early to know that I think. We still only have a tiny amount of data on how BE (v1) and other aftermarket bearings fair after some use.



Incorrect.
This is a photo of a tin/alu bearing (which I've posted earlier) that I partially rubbed down with emery paper. You can clearly see the copper.
But I've yet to see one that's actually worn through to the copper during use.

Hey, long time mate hope all good.
Haven't followed your investigation lately, have you seen 702/703 shells even coming down to the copper (i.e. not through)?

Hey , I'm ok, hope you are too.
Can't remember if I've already mentioned it, but I've now done 2 track days in my M3 , one at Brands Hatch indie, the other at Cadwell park. Have you done any?
Re 70x bearings. This photo by nicke_1 is possibly the 1st photo showing one worn to copper (you've seen it already), but tbh it isn't a great picture as the bearings are showing very dark, so we can't be sure.

Also Fezza seemed to think his bearings are 70x bearings and are definitely showing copper, but I wonder if they are the earlier type. I need to chase them both up about that, thanks for reminding me

Oh and only 1 other person (Fezza) has done the little experiment on their old 70x shells, no one else seems interested .

nicke_1 wrote

I guess that you mean cyl #7, top bearing (once again, sorry for the bad picture, a new one has been uploaded - see my previous post). Measured the play for the old bearings for cyl # 4 and 5. For cyl #5 I got 0,051mm for the old bearing and 0,038mm for the new BE Bearing... Weird. I'm going to remove it tonight and do a new measurement. Good thing that I choose reusable ARP-bolts...

Hi nicke, sorry to ask again, but even in the better photo the bearings come up looking very dark (probably because the bearings are on a white background and the flash was used).
If you could take a photo of them again on a slightly darker background and with natural daylight, and without the flash, they should come up much better . We would appreciate it.

Fezza wrote

I posted this a while back from a friend's LCI after 125k miles: https://www.m3post.com/forums/showpost.php?p=26312408&postcount=1688 maybe that was the first one you saw showing copper?
..........

Hi Fezza, sorry I seemed to have missed or forgotten about that part of your post, are you completely sure they are the later 702/703 bearings? To me they look like the earlier 088/089 bearings. Just because your car is an LCI variant doesn't mean it has the later bearings. Not sure if you just going by your car's year?

Assimilator1 wrote

Oh and only 1 other person (Fezza) has done the little experiment on their old 70x shells, no one else seems interested .

Hey, I answered when you asked about the experiment, but you didn't follow up then.

I've got 70x shells at home.

Will message you when I can sand them, ok?

jvictormp wrote

Hey, I answered when you asked about the experiment, but you didn't follow up then.

I've got 70x shells at home.

Will message you when I can sand them, ok?

You did? Apologies if I missed that (was that in a thread or via PM? [edit, Don't see you listed in my PMs]).

And yea great if you can , if you can sand 1 or 2 of the worst worn shells across the middle of their wear patch, like I did in the photo I posted here on the 19th (you don't need to go through to copper if the silver layer is revealed).

Hi folks,

I haven't posted or been active in forever. My 2012 E92 6MT is at 102K miles. it has become my daily driver, so no tracking or mods. I've been doing regular scheduled maintenance and oil changes at approx every 7K miles.

Since I've not been keeping up, what are the current thoughts on rod bearings. I know its a very polarizing topic. I'd like to hear about the various points of view and if there are any best practices.

Is my car less susceptible since it is at the tail end of the generation? Any other bugaboos I need to know about? My only issues over time have been the idle control valve.

Thanks in advance!

Peahi wrote

Hi folks,

I haven't posted or been active in forever. My 2012 E92 6MT is at 102K miles. it has become my daily driver, so no tracking or mods. I've been doing regular scheduled maintenance and oil changes at approx every 7K miles.

Since I've not been keeping up, what are the current thoughts on rod bearings. I know its a very polarizing topic. I'd like to hear about the various points of view and if there are any best practices.

Is my car less susceptible since it is at the tail end of the generation? ...

No. Poorly spec'd tolerances didn't change with generation, only bearing materials.

Peahi wrote

Hi folks,

I haven't posted or been active in forever. My 2012 E92 6MT is at 102K miles. it has become my daily driver, so no tracking or mods. I've been doing regular scheduled maintenance and oil changes at approx every 7K miles.

Since I've not been keeping up, what are the current thoughts on rod bearings. I know its a very polarizing topic. I'd like to hear about the various points of view and if there are any best practices.

Is my car less susceptible since it is at the tail end of the generation? Any other bugaboos I need to know about? My only issues over time have been the idle control valve.

Thanks in advance!

Best practice = BE Bearings with ARP Bolts. Both are available from BE Bearings website.

Your Throttle Actuators should probably be replaced before they fail.

Peahi wrote

Hi folks,

I haven't posted or been active in forever. My 2012 E92 6MT is at 102K miles. it has become my daily driver, so no tracking or mods. I've been doing regular scheduled maintenance and oil changes at approx every 7K miles.

Since I've not been keeping up, what are the current thoughts on rod bearings. I know its a very polarizing topic. I'd like to hear about the various points of view and if there are any best practices.

Is my car less susceptible since it is at the tail end of the generation? Any other bugaboos I need to know about? My only issues over time have been the idle control valve.

Thanks in advance!

Much less controversial than it used to be I think, dare I say there's a general consensus(?) that regardless of bearing type, the tolerances seem to be inadequate and the bearings should be changed.

And whilst the later tin/alu (and yes they do have copper too) do seem to suffer less wear in general (e.g at most it is very rare their copper is exposed) compared to the earlier lead/copper bearings, they still suffer more wear than should happen to rod bearings in an engine, and they're not immune to bearings being spun either, although it seems less likely.
IMO if you chose not to do the bearings in an earlier engine with lead/copper bearings, you're bonkers! lol. If you chose not to in a later engine, although a lesser risk, it's still a dubious risk.

Btw, mixed ACL bearings hand measured (i.e not simply 2 1/2 packs of std and large shells boxed together!) are a worthy alternative to BE bearings. If you can find someone to hand measure them (Mporium do).
New OEM rod bolts are ok to use but are a right rigmarole to fit, so the extra labour cost of fitting those might offset the saving from the cost of the bolts (and ARP rod bolts are reusable).

Oh, throttle actuators are another major bugbear of our M3s (as DrFerry mentioned), don't waste your money with new OEM ones, get rebuilt ones by rebuild.org (their maybe others?), or whoever supplies them.

Peahi wrote

Hi folks,

I haven't posted or been active in forever. My 2012 E92 6MT is at 102K miles. it has become my daily driver, so no tracking or mods. I've been doing regular scheduled maintenance and oil changes at approx every 7K miles.

Since I've not been keeping up, what are the current thoughts on rod bearings. I know its a very polarizing topic. I'd like to hear about the various points of view and if there are any best practices.

Is my car less susceptible since it is at the tail end of the generation? Any other bugaboos I need to know about? My only issues over time have been the idle control valve.

Thanks in advance!

We now know most of the "wear" we've seen on the later (702/703) rod bearings is actually superficial discoloration. And we are still struggling to find a single instance of 702/703 bearings that have clearly been worn down to the copper we now know they contain. Given that, I think it's safe to say 702/703 rod bearing longevity has been greatly underestimated.

With no one actually measuring 702/703 bearings to see how much they've worn, the only real evidence of premature wear are the engine failures that have occurred. Those are real, but extremely rare as a percentage of engines built, and most seem to have been at lower mileage than yours (raising the probability of defects, assembly issues, and/or abuse).

Also, the idea that wear on the 702/703 bearings is impossible to track via oil analysis is now in serious question. They don't have lead but they do have copper, so you could still look out for a copper spike (though a lack of one would NOT mean all is well).

Keep in mind that rod bearings don't have to last forever. They just have to last until the engine needs a complete teardown (because at that point you're replacing the rod bearings anyway as part of the rebuild). 088/089 bearings (the ones in earlier cars) seemed to fail that test pretty regularly, with pic after pic showing copper. The same does not seem to be true of 702/703 bearings.

So, I'm not saying your rod bearings will last forever, but... TBH, I wouldn't be worried if I were you. Could it blow up tomorrow? In theory, absolutely. The question is whether the risk is high enough to be worth tearing into an engine and introducing the possibility of assembly errors etc. A couple of years ago, I'd probably have said yes. These days, I don't think so.

I had my original 088/089 rod bearings replaced with 702/703 bearings. OE rod bolts, too. 4 years, 68k street miles, and 9 track days since then. Knock on wood, but zero sign of issues so far. #ShrugLife

Bearings are up on my list next! My shop is recommending BE bearings with their ARP bolts. Seems many have used these with good results.

The comment about 702/703 shells causing fewer engine failures is incorrect. There is only one set of data that I've seen on the subject a few years ago. It that data set, 702/703 shells had numerical higher instances of bearing failure than the earlier 088/089 shells. I don't know the production numbers of each, so I can't tell you if that is less per-capita than 088/089 shells; but in actual numbers, they were greater...and when failed, they tended to cause more damage (e.g. holes in the block, etc.).

IamFODI wrote

With no one actually measuring 702/703 bearings to see how much they've worn, the only real evidence of premature wear are the engine failures that have occurred. Those are real, but extremely rare as a percentage of engines built, and most seem to have been at lower mileage than yours (raising the probability of defects, assembly issues, and/or abuse).

BE is in the process of purchasing a custom made measuring device that will measure shells to 0.000001 inch accuracy. If anybody wants to send used shells their way, I'm sure they'll be happy to measure them. However, I don't know what good that will do because you don't have a baseline of the same shells when they were new.

Green-Eggs wrote

The comment about 702/703 shells causing fewer engine failures is incorrect. There is only one set of data that I've seen on the subject a few years ago. It that data set, 702/703 shells had numerical higher instances of bearing failure than the earlier 088/089 shells. I don't know the production numbers of each, so I can't tell you if that is less per-capita than 088/089 shells; but in actual numbers, they were greater...and when failed, they tended to cause more damage (e.g. holes in the block, etc.).

What data set?