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02-23-2019, 07:32 PM | #903 |
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Consider this: The work done by BE -- which is widely and not-altogether-unreasonably considered definitive and complete -- was WAY more demanding and thorough than most people would even attempt. A truly comprehensive analysis would be vastly more demanding than that. That's a hell of a lot of time, money, and talent for something that isn't guaranteed to yield anything useful. I don't think we'll be seeing it any time soon.
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02-24-2019, 06:36 AM | #904 | |
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It's all about probabilities. Most S65's are still driving around on original bearings and they're not blowing up; sure some do, but most don't. Then consider the main bearings - you might replace the rod bearings but in what shape are the mains? The only way I'd do bearings is through a complete engine out rebuild. |
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02-24-2019, 06:40 AM | #905 | |
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02-25-2019, 03:04 PM | #906 |
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My bearings after 84.000km
Last edited by Willem3; 02-25-2019 at 03:09 PM.. |
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02-26-2019, 07:05 AM | #907 |
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To me they appear to be a little more worn than others at this mileage...
What year is the car? Does the car get driven a lot in traffic? Does it get to see the redline often? Glad you got them changed Now enjoy the car, with more peace of mind! |
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02-26-2019, 07:59 AM | #908 |
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Ha, all these bearing pictures! To me they look really quite good compared to most I've seen but there you go.
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02-26-2019, 08:29 AM | #909 |
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The mechanic said the bearings looks fine for the mileage.
It’s a manual 2008 E90, having the car since 60k km. Service history. every 10.000-15.000km service No history of track use. Driving style, drive the car all year round but only occasionally and fun rides. No traffic use, very easy when cold en when its nicely warmed up I like the sound of the screaming V8, driving style is very 50% sporty and 50% cruising. |
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02-27-2019, 08:41 AM | #910 | |||
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There is also a very detailed thread discussing oil flow and how it is affected by bearing clearance here: Quote:
Yes, replacing rod bearings does not address main bearing clearance concerns. That said, the main bearings have not been shown to be a significant problem on the S65 as very few main bearing only failures have been documented IIRC. Perhaps someone could chime in on the actual numbers if they have them handy. To conclude: inadequate rod bearing clearance will lead to premature bearing failure, and likely a ruined engine. Certainly, it will be an engine-out repair. Statistics and probability demand that a certain percentage of S65 engines have less than acceptable rod bearing clearance. Installing any rod bearing that establishes appropriate bearing clearance will resolve THAT specific problem. Cheers,
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02-27-2019, 09:02 AM | #911 |
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There are only several posts of replaced rod bearings. Not enough to draw any conclusions yet. There is one showing nice looking replaced WPC treated bearings, there is one showing nice looking VAC coated bearings, and there is one showing nice looking BE bearings.
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02-27-2019, 09:22 AM | #912 |
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One bearing shell from one engine after 30k miles, not even clean in the pic, and that's supposed to confirm a solution for all bearings in thousands of engines for 60k-100k+ miles?
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02-27-2019, 12:50 PM | #913 | |
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Take the flow data and photos for what it is worth and draw your own conclusions. The photo shows, but it does not prove, that the BE bearing is doing EXACTLY what it was designed to do: operate as a proper hydrodynamic bearing. That is a good start. I really do look forward to more people pulling BE bearings with high mileage from their engines to show how they perform. Given the fundamentals followed by BE, I would suggest they will look great in all cases. If I am wrong, I am wrong. Personally, I choose to put my trust in the professional engine builders who identified the issue, measured a number of engines, designed the new bearings, tested the solution and shared the data with us. I am not saying to anyone that BE is the ONLY solution. That was a personal choice I made. IMHO, if we do not support people like BE now, why would anyone go through the effort they did in the future? What I am saying is that when replacing your rod bearings, the choice should be one with proper clearance. There are a few different choices on the market at this time that offer increased clearance. Pick the one you comfortable with and install them. Cheers,
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02-27-2019, 02:05 PM | #914 |
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You could say the picture of the WPC bearings, which had more miles on them, show that stock clearance is fine and that just WPC treatment is needed. And you could say the picture of the VAC coated stock bearing, the mileage of which I don’t recall but Malek posted it a couple of years ago, shows that just a coating is needed even if it slightly reduces stock clearance.
I think replacing the bearings is a good choice, and that probably the later VAC increased clearance bearings, the BE increased clearance bearings and the ACL increased clearance bearings are an even better choice. |
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02-27-2019, 03:31 PM | #915 | |
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02-27-2019, 06:29 PM | #916 | ||||
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02-28-2019, 07:14 AM | #917 |
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Here's a post I found on MRF Engineering Facebook page, showing WPC bearings removed after just 3k miles. Aside from the cyl 1 which is smashed, all the rest seems to be also wearing pretty badly.
I wonder which bolts were used there. https://www.facebook.com/mrfengineer...type=3&theater
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03-01-2019, 02:52 PM | #919 |
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03-02-2019, 10:00 AM | #920 |
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This is perfect for me. I live in Houston and have family in Dallas (:
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03-03-2019, 08:34 AM | #921 |
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RB wear question
I don’t know if this has been answered before but if there’s abnormal bearing wear due to tight clearances doesn’t the problem self correct after some wear?
Or is it a downhill process that once wear starts it doesn’t stop? |
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03-03-2019, 08:42 AM | #922 |
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That has been raised before. Probably to some degree it is true, or at least true that wear slows after that initial wear. It is also possible that once you wear away the surface of the bearing that is designed to maintain the oil film, the film may not be as correct and friction may go up.
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03-03-2019, 01:27 PM | #923 | |
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There is a designed bore shape that the bearing is supposed to maintain through its life. An inadequate oil clearance causing erosion of the bearing surface is not desirable and affects how the hydrodynamic bearing oil wedge functions. Since the wear does not occur to the entire 360 degrees of the journal surface, the bore shape becomes more eccentric over time which has undesirable effects to its function. Additionally, this abnormal wear is removing the soft babbit layer of the bearing surface which is intended to embed debris that may otherwise damage the crankshaft journal or other parts. With excessive wear removing the soft babbit and exposing the harder binding layers, the risk of debris scoring the journals and leading to seizure increases exponentially. There is a great document here about how bearings work here. Especially note page 4 on this topic. http://kingbearings.com/files/Engine..._They_Work.pdf |
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03-03-2019, 04:16 PM | #924 | |
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