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07-20-2017, 01:15 AM | #287 |
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So someone confirmed why BMW designed the bearings the way they did and then repeatedly didn't go with the seemingly obvious solution that BE came up with? Or is it that BMW went through what was likely a financial/PR shitmare with S54 rod bearing recall, and then assigned an intern to design rod bearings on the S65 who forgot/overlooked/was oblivious of the industry standards for clearances? I doubt that.
To be clear, I think BE could potentially be a great solution, and just because BMW is a big OEM certainly doesn't mean they're right. But I have a sneaking suspicion that they had a compelling reason to go with their bearing design. Today and yesterday I called 7 different very very competent and well known BMW tuners and engine builders in the US who unanimously agreed with the following: 1. WPC treated OEM bearings are an improvement that is proven and low risk 2. BE bearings have good logic but we don't really know yet if it's been validated. They do not recommend using them yet but also don't recommend avoiding them. What are the downsides of the extra clearance that BMW didn't want? 3. They all put WPC treated bearings in all of their race builds and street engines BE has not been validated enough for me to feel comfortable. I'm making an appointment to get WPC bearings installed, and maybe next round will be BE if a more compelling amount of real world data is available (it will be). Forums have a very good but also very dangerous tendency to groupthink. What is the consensus here isn't necessarily in agreement with the majority of professionals who are dealing with dozens of S65s regularly. |
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07-20-2017, 09:32 AM | #288 | |
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There's also quite a bit of real data posted here: http://www.m3post.com/forums/showthread.php?t=1337998 Bert @ BE Bearings lives in your area. Why don't you sit down and have coffee with him and pick his brain? I'm sure he can tell you the whole history and give you much more information than I can. Send me a PM if interested and I'll put him in touch with you. |
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07-20-2017, 09:46 AM | #289 | |
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07-20-2017, 11:24 AM | #290 | |
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It makes sense from a technical analytical standpoint that BE bearings would be better. I have said repeatedly that I understand and mostly agree with BE design. I've read that thread you linked and every other thread I could find on the subject. Even on the last page in that very thread someone brought up that "it could be more complicated than this" As a mechanical engineer myself, I have seen beautifully engineered mechanical systems, with millions of dollars worth of resources spent designing and prototype testing said system, end up having an "oh wow" realization when it gets to testing hundreds/thousands of units for long periods of time. It is completely unreasonable and impractical to expect BE to be able to do that prior to selling their product, so to me right now there are lots of helpful test cars out on the roads validating BE design. Since I'm not personally willing to make that leap, I'm going to go with an option where it is pretty well understood how it performs in the field. The BE warranty as described in the thread you linked seems pretty tedious, and reasonably so from their standpoint, and not something that would be enough to wipe away my concerns. I still see nobody has found out why BMW didn't want that clearance, or at least they haven't posted it here from what I've seen. You won't be able to convince me that BMW S65 engineers didn't evaluate or test bearings at the industry standard clearance for this motor by just saying "they messed up." To me it is even more likely that they started there and moved away from it for a reason. |
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07-20-2017, 11:59 AM | #291 | |
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In any event, the whole system of the hydrodynamic bearing consisting of the shells, crank, rods and rod bolts, oil supply (especially the oil supply, i.e. entrained vapor being a particularly interesting aspect), etc, etc, is a profoundly complicated subject as you know. I specialized in fluid dynamics and heat transfer in graduate school (granted this was 35 years ago now), and I can say without question tribology is a very complicated subject and especially if you look into numerical modeling (given the constraints of the CFD models). One aside in this whole subject is lack of discussion about the non-Newtonian behavior of multi-weight oil which massively complicates any analysis since it has a non-linear viscosity versus shear rate. Now add in the *huge* changes in local shear rate in the squish zone of the bearing along with large local temperature changes, and you have a local viscosity that becomes a very complicated function of local shear rate and local temperature in the bearing squish zone. Hence the reason "industry commonplace rules of thumb" have long been used...then when something "doesn't work", it becomes guesswork with sometimes educated guesses and sometimes not. A good book to crack the surface on the subject is Engineering Tribology by Stachowiak and Batchelor.
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07-20-2017, 12:05 PM | #292 |
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The Blackstone analysis will be of limited use -- there will be a lot of weird particulate counts due to break-in and assembly.
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07-20-2017, 01:05 PM | #293 | |
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07-20-2017, 03:06 PM | #294 |
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Doing mine on aug 3rd ftw
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07-20-2017, 06:38 PM | #295 | |
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I agree that there is not loads of data out there for either aftermarket solution, yet you have nothing from BMW either other than they are still in business. I went with BE. There was data and valid engineering assumptions. That, to me, is better than reputation. |
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07-20-2017, 07:22 PM | #296 | |
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The bearing clearances on the S65 are wrong by what metric? Because you compared them to the rule of thumb? Or because the bearings have x% of field failures which are for sure attributed to the clearance? What is the actual data you are referring to? |
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07-20-2017, 09:32 PM | #297 |
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There is no data that proves the clearance is the problem. It is all hypothetical arguments and there are valid arguments that it is something else (bolts, improper care etc).
The only thing that is clear is there is a problem, that can cause bearing wear, that can also cause a catastrophic failure. It also seems by replacing the bearings and bolts (with any of a varied choice of replacements) the risk of this failure is greatly mitigated. This problem is varied randomly across cars from being evident early to not being evident at all and there is probably only a very small % of cars affected. I have chosen to go with VAC, but was also considering BE, though it seems the WPC coated ones are fine also. I am getting the VAC ARP bolts. I am yet to see any evidence that any one of these choices is better than the other, or worse for that matter. It is all opinions, and frankly opinions hold water like an onion bag. I still would not be surprised if these solutions also failed at some stage, it is a high performance engine and this is a by product of the stresses it faces. I hope it doesn't happen any time soon though!! |
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07-20-2017, 10:06 PM | #298 |
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Good read, especially from the skeptics... who seem to have a LOT of trust in BMW.
We all know about the S54 bearing issue. There's the Nikasil nightmare from the E39 V8's. Let's not forget about the VANOS failures on the S54, which has been corrected by the aftermarket. Then there's that damn rear subframe issues that went from the E36 to the E46 models, that has also been corrected by the aftermarket. Radiators necks used to pop all the time on E36 models. We also have to deal with failing throttle body actuators, and idle control valves and don't even get me started on the N54 and all its issues. I was lucky and only had about 3 recalls and no engine or turbo failures. BMW doesn't own up to most of it's failures until a lawsuit or the media takes hold. As for the BE not being proven, that is true, but Malek has changed out MANY sets of VAC bearings and inspected them later on and they have all been perfect according to his thread. From what's he's said, the VAC are pretty similar to the BE in terms of clearance and both are coated. It's a good initial sampling, as opposed to almost all OEM bearings that have been changed out having considerable wear for the mileage. . This last point is strange to me since most people do feel the defect only affects a small percentage of cars, but almost all the bearings that have been changed out looked pretty bad. At least, that's what I've noticed when I'm on the boards. .
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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07-20-2017, 10:11 PM | #299 | |
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What sets the S65 apart in your mind that makes BMW's decisions the right ones and the rest of the industry wrong? The "rule of thumb" that sounds so dumb is mentioned in multiple books on the subject and engine design. That rule is mentioned side-by-side with the warning that higher output and higher RPMs need greater clearance, not less; but if you use less clearance, you must use thinner oils. BMW ignored all aspects of that dumb rule on the S65/S85 and they're the ones who seem to have the problem on those motors. There's nothing different about the S65 that makes it immune to these same rules, if there is, I'd like to know what sets it apart. So my recommendation is for you not to change anything at all because the WPC treated bearings are still stock bearings. If there's no issue with the stock bearings, I don't think you should run the extra risk of replacing them with more stock bearings. BTW, out of curiosity, how did you manage to call seven shops in your area, and not run into four of the biggest shops in your area all using BE Bearings? I don't think I'd trust a no-name shop with advice or work on the S65. Last edited by Green-Eggs; 07-20-2017 at 10:20 PM.. |
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07-20-2017, 10:14 PM | #300 | |
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The test sample is too small and it is not a double blind study. We are only hearing from people who have had issues. |
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07-20-2017, 10:24 PM | #301 |
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We'll NEVER have a randomly assigned, double blinded study here. My point is, there are many who changed their bearings out WITHOUT a problem, and the vast majority show heavy wear.
This is different than the cars with blown motors. These are cars that seem to be driving normally but there seems to be a problem with excessive bearing wear. .
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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07-21-2017, 12:51 AM | #302 | |
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You and other posters are misinterpreting what I've repeated many times - BMW could very well have made a mistake, and it wouldn't be their first, but BE hasn't proven, to my level of expectation, that they solved it with no other side consequences. There's a very good chance they did solve it, but I see no upside in taking that risk myself. Reread my comment about the 7 shops. Only one of them was in my area. They are actually members here and are willing to install the BE bearings. They simply recommend WPC OEM until more field data is available. Same for Bimmerworld. Same for the others. Using and recommending are different things. |
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07-21-2017, 10:39 AM | #303 | |
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I agree! I honestly don't think BMW would knowingly jeopardize their product or overlook something as simple as bearing clearance. It would be easier for all of us to sleep at night if BMW would give us a good reason as to why the tolerances are so close, but until then we must believe that they are for a reason. Until we have good evidence that less clearance with smaller bearings has no negative effect, better to just go with same tolerance bearings that have better wear properties. The tight clearance doesn't bother me, its the wear that does. As long as there is a way to keep them from wearing or lubricated, I don't mind the tight tolerances. Especially with an 8250 rpm engine |
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07-21-2017, 11:21 AM | #304 | |
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If you have the older lead/copper bearings, you're probably safer than the newer cars with the newer bearings and you can monitor wear using oil analysis. If you have the newer bearings, the car is a ticking time bomb with no way of monitoring bearing wear. WPC treated bearings are based on the newer bearings so oil analysis won't help to monitor wear. VAC bearings use lead/copper so may be a better choice if sticking to stock clearance bearings. BE Bearings also use lead/copper bearings so it also works.
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07-21-2017, 08:00 PM | #305 | |
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Are they on the bearing registry? .
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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07-22-2017, 02:32 PM | #306 | |
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It's pretty entertaining there are people who think there is not a bearing issue on S65s. What more evidence is needed? Over 90% of the bearings that come out of s65s before failure are worn at levels that makes no sense for their mileage I bought my 2013 brand new and followed the best warming up and oil change procedures, as well as break in, on the planet. Never driven in winter. Always bmw oil. I changed my bearings at 31k miles and they were completely fucked. Someone may think 'oh well but you tracked the car'. Yeah but, i tracked my E46M 10x more and the bearings at 130k miles looked way better than my 30k mile E92. To someone else who said they got arp bolts and there is no proof of what bolts are better: i remind you that the fact that you don't search for it doesn't mean there is no evidence. Since the E46 there has been data which shows the arp bolts distort the bore more than the oem ones. On the e92, be published detailed data on the arp bolts. Either use be-arp bolts or oem ones. This is well established with data behind it. End of story. |
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07-22-2017, 02:46 PM | #307 |
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So for e46 the arp does seem to cause more bore distort. I have go thru the graph and all, overall it seems this is the same case for e92 as well? there are sooo many graphs lol...from what I can tell,overall it seems the arp bolts seem to cause more distort as well , or am I reading the graph(s) wrong? Altho I will most likely go arp bolts when I do it. So much easier to install. |
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07-22-2017, 03:28 PM | #308 | |
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The early ARP 2000 design caused issues, the BE ARP design does not. You didn't fully read everything. Read towards the bottom of this page: http://wiki.rcollins.org/core/index..../S85_Rod_Bolts
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