deansbimmer wroteSo aren't these the standard bearings with their coating? So standard clearances minus a little for the coating?Fixed the pics. They're VAC/Clevite.
Very clean bearings anyway!
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And after finally going through this whole thread! (not read it all though), a couple of interesting observations I'd like to note of all the dozens of photos posted here of RBs (I've looked at them all, obviously not including ones that now have a broken link), only 2 posts of photos of OEM RBs are shown in good condition with slight typical wear expected with any engine!
The newer Alu/tin bearings mostly seem to fair better (unless that's a limitation of just looking at photos?), although they seem to often get those dark spots from embedded debris.
With that, I want to reply/ask questions to a few people.
Why do people say the latter OEM alu/tin bearings have no extra clearance over the earlier ones when they do? At least according to the bearing wiki. The minimum variance has been increased from -0.00090" to -0.00035". (And maybe that's why they appear to fare a little better?)
Why do people say a new crank for these is ~$10k, when a quick search I did today shows them to go for about £/$3k? (not that that's cheap by any means though!
) (was I looking at old posts??).serranot You said - I think that’s my point. If it has wear, it’s not ok. How is one supposed to know what “ok” is vs “not ok"
As far as the copper/lead bearings go, not ok is through to the copper, at this stage scouring & galling is possible & increasingly likely as more of the lead is worn away.
Ok* is where their is still lead completely covering the wearing surface, the bearing isn't at risk of imminent** failure.
*and when I say ok, I don't mean it's in normal condition for the mileage of the engine compared to engines generally. I mean it's ok for S65's & isn't in immediate danger of causing damage.
**how long is imminent? Not a foggiest lol! So whether this wear has been picked up by oil reports, or by the RBs being removed, knowing that these engines suffer from premature RB wear &/or failure it's still worth changing them then.
ThatM3guy wroteYou/we can't know that, my belief is that based on the tight clearances they're likely to start with, most of the wear occurs early on*, in your case, yes I think most of that lead was 'ground' away within it's 1st 55k miles. Otherwise the oil reports would've picked it up, although this leads on to something IamFODI said......It’s even more concerning as I am showing strong, consistently healthy oil reports and yet the bearings have wear and some have significant wear. You could argue that occurred in the first 55k, but I doubt all wear occurred then. Interesting huh?
*I know Deansbimmer is sceptical of this idea, saying something along the lines of the babbet layer being 'ground' away like this causes damage to the remaining layer & hence faster than normal wear, (not saying he's wrong as he has vastly more experience than me on building engines
), but enough of the babbet layer could be left to account for the wide range of mileages that these engines achieve.Both points could be right, heavy wear occurs early on and where the RB doesn't fail then, the fractional extra gap achieved & if enough of the (damaged) babbet layer is left, it keeps the engine going for (usually) several 10k's of miles, but of course if the engine is stripped down at any point after the early stages the bearings will be found to have premature wear.
IamFODI wroteRef acid attacks from extended oil changes, I think it's fair to say that with the vast majority of RB photos posted here plus the OCI info shown, bar 1, they have all changed oil under the standard interval, so this is not a likely scenario. Also, surely the oil report would find other signs of extended OCIs? (even if the oil life wasn't reported).Well... yes and no.
Like most oil analysis labs, Blackstone gets its wear metals counts from ICP spectroscopy, which only catches particles up to a certain size -- and not all mechanical wear chucks out particles in that size range. Some wear modes produce bigger particles, to which ICP spectroscopy is completely blind. Furthermore, ICP-detectable particles can come from chemical processes that have nothing to do with what most people would consider mechanical wear -- processes like acid attack from overextended oil change intervals, or highly active surface chemistry from aggressive anti-wear additives in the oil. So, if you see big numbers, it's difficult or impossible to say whether they're anything to worry about. And if you see low numbers, maybe everything's fine, or maybe there's a wear mode that ICP spectroscopy can't detect. You have no idea just from looking at the report.
S65s with the original BMW rod bearings are lucky in that they sometimes produce lead and copper particles in ICP-detectable sizes when their rod bearings wear abnormally, AND they don't seem to produce ICP-detectable lead or copper in significant quantities for any other reason (barring leaded fuel or new oil cooler hardware or something). So, if you see those high numbers from one of those engines, then yeah, it's probably rod bearings. But again, if you don't see those numbers, you have no idea.
We don't know how or to what extent the updated BMW rod bearings or any aftermarket rod bearings will show wear on ICP spectroscopy, if they even do at all. Aftermarket bearing manufacturers will say they went for leaded bearings to facilitate oil analysis, but there's been no rigorous testing of that idea and the data from the field is incomplete. What little evidence we have on the updated BMW bearings is not favorable, though we don't even know what we're looking for because we don't know what they're made of.
ICP spectroscopy can be useful for tracking early-stage wear when you have a lot of background knowledge about the application in question. You have to know in advance whether and how any potential wear problems will show up on oil analysis, and you have to know about any possible sources of false-positives. Then you have to sample frequently enough to catch the wear while it's still in that early stage, before it starts producing particles too big for ICP spectroscopy to detect.
In other words, it requires a bunch of things that are difficult if not impossible for an end user running oil with unknown chemistry on a hand-built car engine with unknown metallurgy operated in the real world under uncontrolled conditions. And that's the main problem here.
It's generally assumed that frequent and regular sampling can reduce the futility of oil analysis in an application like this. That's why I'm doing it. But I'm sampling every 5k miles and using a slightly more extensive analysis package (Polaris Labs Advanced Engine Plus), and I'm not taking low numbers to mean a clean bill of health. I'm already planning to revisit my rod bearings within 60k-80k miles after the first change. What I'm looking for are signs that I might have to do them sooner, as well as signs of other kinds of trouble like fuel dilution and other contaminants -- which, by the way, is where oil analysis is truly useful in a car engine. Maybe that's another thread.
The set of oil analysis reports you had prior to changing your rod bearings wasn't so much a consistent history as a few snapshots over tens of thousands of miles. And again, that's in addition to the serious limitations of oil analysis for tracking wear.
Is what you did better than nothing? Absolutely.
Is it mysterious that oil analysis missed your rod bearing wear? Not in the least.
Re - which only catches particles up to a certain size -- and not all mechanical wear chucks out particles in that size range. Some wear modes produce bigger particles, to which ICP spectroscopy is completely blind
What wear modes? And what particle size?
Not saying you're wrong, (you seem to know something about oil analysis
, where from?), just you're the 1st person I've come across whose actually given a logical plausible reason as to how the oil reports might not pick up bearing issues.Interesting you say about sampling every 5k miles, I'm (still) in the process of looking at any S65 oil reports + photos I'm coming across, and from the small numbers I've found so far (31 to date, I'll be posting a thread about it), it seems that 5k miles is the maximum sampling interval you want to do to stand a good chance of picking up RB problems with the cu/pb bearings before damage is done to the crank.
Btw, my general position on the RB S65 problem is this, I don't question that their is a RB problem with the engine. I do question whether oil reports can miss it (although you might change my mind on that) and I think it's more likely that some people aren't using the oil sampling properly, e.g a massive mileage gap between oil analysis & RB failure or strip down, only doing 1 sample, and when stripped down some people saying the bearings are completely knackered when they're not! (primarily talking about the cu/pb bearings here), e.g not gone through to the copper (not saying that the bearings are fine either!
just not imminent or near imminent failure).And going by what I've read to date it does seem that the OEM bearing clearances are much too tight at the minimum end!
I've got a 2008 M3 with 75k miles which I bought in November, just had the oil sampled by The Oil Lab & it got a good report with 3 & 4 ppm cu & pb
, oil's done 3.3k miles.Atm I'm still looking into this issue whilst I've taken the car off the road for the winter (until April), due to cost reasons I'll only be doing a total 2k miles for my 1st yr with it, may go to 3k/yr afterwards, I plan to do a few track days each yr too.
The oil report is to see if I'll be ok for this year, so far, I believe I am! I plan to oil sample again the end of this year. If I'm 100% sure oil sampling will definitely pick up bearing issues I'll carry on doing that, but even if I'm only 99% sure I'll be changing the RBs next year (probably with ACL ones).
Hopefully I haven't overlooked an obvious points!
Scharbag wroteHow do we know they don't have anymore new engines left?.......
Also, if it were a simple $2500 engine swap, I would not worry about it regardless. Unfortunately, BMW does not have any new S65s in the warehouse because they have all been used due to the horrendous number of failed engines. Used engines are not cheap or easy to find a really good one. Rebuild costs are ridiculously expensive when done properly due to the complexity of the engine and the cost of parts. Regardless to which option you choose, the labor to replace the engine is also not cheap.
But everyone is entitled to their own opinions.
Cheers,
).
That's more than the cost of ACL bearings! lol
Anyways thanks for clarification. BE page still refer to the standard shell claiming not increased clearance but maybe way back when that was the case. All a bit confusing, but if I would guess its the same shell all along since they left the coated OEM. Anyway, some of them comes out in brilliant shape.
