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07-21-2016, 03:14 PM | #3191 | |
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I know this is old but this guy is annoying and ignorant...
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09-06-2016, 04:36 AM | #3192 |
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Question: my rod bearings clearance were measured at 0.063mm. Are they out of spec for my engine?
Mileage is about 82000 km. I need advice as BMW AG claims max clearance is 0.07mm My ride is E92M3. Thank you! Last edited by masschaoz; 09-06-2016 at 05:44 AM.. |
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09-06-2016, 10:12 AM | #3193 | |
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If I'm reading his post right it seems he thinks pre ignition and detonation are the same though, which is incorrect. Here's a great read on the subject: http://www.contactmagazine.com/Issue...ineBasics.html |
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10-27-2016, 12:25 AM | #3194 |
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With all the recent talk that VAC bearings were designed for extra clearance, I did a little digging today and here's what I found. Not sure how many people are familiar with this, but there's a place where you can look up archived web pages. It's called the "wayback machine." So I looked up the old VAC bearing pages, and here's what came up.
July 1st, 2014: Old VAC bearings (see the price): https://web.archive.org/web/20140701...ine-p2932.aspx January 10, 2015: VAC web page updated for new bearings and new prices. Notice NO MENTION OF EXTRA CLEARANCE! https://web.archive.org/web/20150323...ine-p2932.aspx February 10, 2015: VAC announces new bearings on their Facebook page. VAC calls them "extra clearance" but explain that as follows: "These bearings will give an additional 0.0005" clearance to the OE bearing size. So with the coated bearing shells you will have the OE clearance." That alone settles all doubts what VAC intended with these bearings -- factory clearance was the target. But wait, there's more! VAC goes on to say: "The reality is that you only need enough clearance to get oil to flow into the bearing and the extra clearance is not really necessary." https://www.facebook.com/vacmotorspo...53144927883169 February 16, 2015: VAC updated web page. Still doesn't call them "extra clearance" bearings. https://web.archive.org/web/20150216...ine-p2932.aspx March 12, 2015 First reported on m3post that VAC has new Clevite designed bearings: http://www.m3post.com/forums/showpos...postcount=2408 March 13, 2015: RG call VAC and was told new bearings are NOT extra clearance, but match factory clearance. http://www.m3post.com/forums/showpos...postcount=2421 March 18, 2015: RG measures VAC/Clevite bearings. His measurements show 0.0020 inch clearance (0.0003 inch bigger than stock). http://www.m3post.com/forums/showpos...postcount=2470 March 23, 2015: VAC updates web page. Still no mention of "extra clearance" bearings. https://web.archive.org/web/20150323...ine-p2932.aspx March-1 - September 1, 2015: BE Bearings forms, announces extra clearance bearings. September 20, 2015: VAC changes web site, finally calls them "extra clearance" bearings. https://web.archive.org/web/20150920...s65-p2932.aspx From VAC's own words on their FB page, they are clear what they mean. VAC designed the bearings with 0.0005 inch extra clearance such that once they add the coating on top, it will equal factory clearance. There's plenty more I didn't quote from their FB page where they start talking about how extra clearance isn't all that important, it's the coating that makes the difference. So I think what we have here is an example of VAC bowing to public pressure and changing their marketing to match what the market demanded -- extra clearance. By VAC's own words, they are not offering extra clearance bearings. But if you look at their web site, and the comments of people on this site, you'd think VAC is offering extra clearance bearings, when in fact they're not. |
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10-27-2016, 08:12 AM | #3195 |
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Damn that's a lot of work dude thanks. Problem though. I purchased Vac's bearings in June of 2015 and the website clearly said extra clearance at that time. RG is the one who suggested them to me as the BE's weren't out yet. September 20, 2015 was not the first time the website called them extra clearance, such that it matters.
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10-27-2016, 08:23 AM | #3196 | |
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Who cares? It's business. They're in the business to make money. Either way, their bearings work...sooo I don't see the problem. "Technically" the bearing has extra clearance. If you actually wore through the coating.
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10-27-2016, 09:37 AM | #3198 |
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Ah that explains it. Sure is a lot of time and effort to attempt to bash one of the communities best supporters.
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10-27-2016, 10:57 AM | #3199 | |
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08-07-2017, 10:51 PM | #3201 |
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Here's a new article on bearing selection and clearance found in Hot Rod Magazine. Clevite plays a significant contributing role in the article.
How to Select and Install High-Performance Engine Bearings http://www.hotrod.com/articles/selec...gine-bearings/ |
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08-11-2017, 07:19 PM | #3202 | |
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A colleague of mine who's ex-army who used to command and service tanks saw the bearings and thought it was good to replace, but added the caveat that any time you work on an engine you introduce the possibility of other failure -- particularly with stuff like rod bearings. However, I'm happy to have done it. The engine may still detonate later -- I hope not -- but I've done the best with my limited knowledge to prevent it. |
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09-07-2017, 12:52 PM | #3203 | |
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I have often wondered if the ionic current method BMW uses for knock control on the s65/85 is completely effective, especially with worn out spark plugs (which are used as the sensing element)? |
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10-13-2017, 04:23 PM | #3204 |
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New to owning a 2011 E92 M3. Lots of reading in the last month to familiarize myself with the E92. It is a great car so far, always wanted an M3, now I think I have the nicest style they have made to date (love them all, just love the E9x the most right now).
I would just like to thank the OP (Regular Guy) for all of the hard work that went into this thread (like boat loads, buckets, barrels, bails). It did take me a while to get through some of the banter but at the end of the day, there are a number of very dedicated members that have shared good empirical data with the community. Hats off to you all. I have raced many cars for many years (mostly Honda, but an E36 318 as well) and a B18A1 with 180,000km of street use (no clue how well the engine was maintained as it came out of salvage) plus 7500km of endurance racing shows almost no wear on its rod bearings (we inspected and re-used the rod bearings they looked so good). I realize it does not rev to 8400 RPM but has lived at 5K+ RPM for the last 3 race seasons. My opinion (cause everyone has one): Bearing wear such as is seen in the S65/S85 cannot be considered normal. The literature and information discussed here does support the conclusion that BMW made it a "wee" bit too tight in there. I personally think it is great that there are solutions to this provided by a few different sources. It gives each of us a chance to choose our preferred method to reduce the risk of engine failure. I personally have chosen to go with a bit more clearance, to meet the accepted best practice of engine builders around the world, and I am confident that the new bearings will help extend the life of my expensive S65 lump. I will be swapping out my rod bearings in the near future (currently have 30,000km on it) as a preventative measure to ensure my M3 has a long and happy life of burning petroleum distillates. Again, thank you to all the contributors that shared such great data with the members of this forum. |
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10-18-2017, 07:14 AM | #3205 |
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Came across a very extensive oil testing blog by a ME. He devotes an entire section to S85/65s. I found some of the information interesting.
https://540ratblog.wordpress.com/201...-test-ranking/ "29. Eliminating BMW M3/M5 Rod Bearing Failures . The BMW M3/M5 models have had an ongoing problem with rod bearing failures for a number of years now. The M3’s S65 V-8 engine was derived from the M5’s S85 V-10 engine. They share the same basic architecture and aluminum construction. . And I was asked if I could offer a recommendation on how to deal with this problem, by reviewing a comprehensive rod bearing failure thread on the M5Board Forum with many, many failed rod bearing pictures as well as additional supporting data, which also included an M3 link to extensive engine tear down inspection/examination data, as well as additional M3/M5 information and data. This is an enormously long Forum thread (it had reached nearly 70 pages when I was looking at it) that was started in 2013 and was still going in 2016. . After going through all that, it turned out that the root cause of all those failures was that BMW had designed/built the engines with insufficient rod bearing clearance (barely large enough for 5W30 motor oil and WAY too tight for super thick oil), insufficient connecting rod side clearance, and they called for insanely thick 10W60 motor oil, which is WAY too thick for acceptable oil flow/lubrication/cooling. It was a perfect storm of doing multiple things completely wrong to actually “cause” rod bearing failures. It was extremely disappointing to see BMW do such a poor job at designing/building those engines. They actually unintentionally designed the engines so that the rod bearings “would” fail. I would have expected far better from them. . It was noted that along the way since all this began, that BMW has increased the rod bearing clearance a little, and now also allows the use of thinner oil (though many owners still seem to think they should use super thick oil for protection). But, there was no mention of them increasing the rod side clearance, which needs to be correct in order for oil to properly flow through and out of the rod bearings to provide the critical lubrication and cooling they need to survive. . For owners of one of these models, there isn’t a lot most of them can do about the rod side clearance problem, or about the rod bearing clearance issue that their particular model year may have, unless they tear down the engine and have it rebuilt correctly. However, there is one thing owners can easily do to significantly help with this problem. . First of all, everyone needs to understand that motor oil “viscosity” is NOT what determines wear protection. That is just an old MYTH, which some people who don’t understand anything about motor, still believe. So, ignore anything you’ve been told about needing thick oil for wear protection, because using thick oil is one of the worst things you can do to your engine. . Consider the following: . Below is actual motor oil viscosity test data that came out of my Engineering Tests on Motor Oil film strength/load carrying capability/shear resistance: . 20 wt oils rank between number 4 and 191 . 30 wt oils rank between number 1 and 202 . 40 wt oils rank between number 3 and 190 . 50 wt oils rank between number 35 and 199 . The one 60wt oil tested ranks 85 out of 202 The one 70wt oil tested ranks 148 out of 202 . So, as you can see, the various oil viscosities all overlap each other regarding their wear protection ranking position, which clearly shows that oil viscosity does NOT play a role in an oil’s wear protection capability. An oil’s wear protection capability is determined by its base oil and its additive package “as a whole”, with the primary emphasis on the additive package, which contains the extreme pressure anti-wear components. And that has nothing to do with viscosity. . Oil “flow” is lubrication, and using thicker oil will simply reduce critical oil flow for no good reason. Plain bearings, such as rod and main bearings, are components that are not designed to be lubricated just by an oil film, they are designed to be lubricated by a flow of liquid oil. Keep in mind that oil pressure is NOT what keeps these parts separated. Oil pressure is a measurement of resistance to flow, and the pressure only serves to supply/move the oil to the clearance between the bearings and the crankshaft journals, and of course to move oil throughout the entire engine. The crankshaft journals and its bearing shells are kept separated by an incompressible hydrodynamic liquid oil wedge that is formed as the liquid oil is pulled in between the spinning parts. All liquids are incompressible (that’s how hydraulics work, including brakes with their watery thin brake fluid), so it does NOT matter what the viscosity of any liquid is. Thick oil or thin oil will create the same incompressible liquid oil wedge. . As long as sufficient oil is supplied by reasonable oil pressure to maintain that critical incompressible hydrodynamic liquid oil wedge, the crank journals and bearings cannot come in contact with each other, so no wear can occur. And the higher flow rate of thinner oil, supplies more oil volume to the main and rod bearings, which helps ensure that the critical incompressible hydrodynamic liquid oil wedge is always maintained. . Thinner oil will of course flow out from the bearing clearance quicker than thicker oil will. But, by making sure the engine provides “sufficient oil pressure”, the oil supply will always be greater than the oil flowing out, which will maintain that all important incompressible hydrodynamic liquid oil wedge. As long as an M3/M5 engine generates at least 65 psi of oil pressure at higher rpm with thin oil, it will be in good shape. . Oil flow is also what carries heat away from internal engine components. Those engine components are DIRECTLY oil cooled, but only INdirectly water cooled. And better flowing thinner oil will keep critical engine components cooler because it carries heat away faster than slower flowing thicker oil can. This is especially important with plain main and rod bearings, since the flow of oil through the bearings is what cools them. If you run thicker oil than needed, you will needlessly drive up engine component temps. . Here are some comparison numbers from an 830 HP road race engine on the track: . 15W50 oil = 80 psi = 265* oil sump temperature . 5W20 oil = 65 psi = 240* oil sump temperature . Here you can see how the thicker oil flowed more slowly through the bearings, thus getting hotter, driving up bearing temperatures and increasing sump temperatures. And the thinner oil flowed more freely and quickly through the bearings, thus cooling and lubricating them better than thicker oil. And this means the oil coming out from the bearings, and going into the sump, is also cooler. And that is why we see the cooler sump temps with this road race engine example. . If an engine is running hot, use a thinner oil to increase flow, increase internal component cooling, and help keep sump temperatures down. Keeping oil temps down is important to help keep oil below the threshold of thermal breakdown. . Almost no engine should ever need to run oil thicker than a multi-viscosity 30 weight. The lower the hot viscosity rating, the number after the W, the better the hot flow. For example, hot 5W30 flows WAY better than hot 10W60. Thinner oil will also typically increase HP because of less viscous drag and reduced pumping losses, compared to thicker oils. . The churning action of rotating and reciprocating internal engine components, along with oil spraying out from between pressurized components, and overall windage, all contribute in varying degrees, to causing the engine oil to become aerated, which is exhibited by air bubbles/foam in the oil. Air bubble-filled foamy oil, is what typically causes engines running on a dyno to experience oil pressure drops, assuming they have acceptable oil drain-back from the top end, and are keeping the oil pump pickup submerged. Also, air bubble-filled foamy oil, is what typically causes engines being run hard in cars, to experience drops in oil pressure, assuming the oil pump pickup is still submerged in oil. And if that isn’t bad enough, air bubble-filled, foamy oil cannot lubricate critical internal components properly. For proper lubrication of critical components, you need incompressible “liquid” oil, NOT compressible air bubble-filled foamy oil. . This is an issue to take very seriously, if you want to provide your engine with the best possible lubrication protection. If this aerated oil issue is bad enough, it can cause wear, damage or outright engine failure. And it can be extremely difficult to diagnose, in the event of an outright engine failure. Because when you take the engine apart for examination, you typically can’t find anything wrong at all, other than say the rod and/or main bearings that failed. That’s because the air bubbles/foam are long gone by then. . Heavy thick oil such as 10W60, is of course 60 weight oil at normal operating temperature, is slower to release and eliminate air bubbles/foam, than thinner oil such as 5W30 which is 30 weight oil at normal operating temperature. Motor oils do of course contain anti-foaming agents to help control (though not altogether eliminate) air bubbles/foam. But, the air bubbles that will still be present in the oil anyway, have to travel through the oil to be released. And thicker heavier oils slow down that process, leaving compromised lubrication. However, thinner oil such as 5W30, allows air bubbles to travel through the oil and be released quicker, making it a better viscosity choice to fight motor oil aeration issues, and provide the best possible lubrication protection for your engine. . Thinner oil will also drain quicker back to the sump, to help keep the oil level high enough to prevent the oil pump pickup from sucking air during hard braking or cornering, in wet sump systems. . CONCLUSION . Short of rebuilding those engines correctly with proper clearances, which is what is actually needed, the one thing owners can easily do to significantly help with this rod bearing problem, is to run a much thinner oil than the insanely thick 10W60 that BMW had specified for years. I recommend selecting a highly ranked 5W30 API SN oil from my Wear Protection Ranking List, which will make a HUGE improvement in rod bearing oil flow/lubrication/cooling, compared to the more commonly used super thick 10W60. This one significant change may well prevent having to rebuild those engines, and would go a long way toward eliminating rod bearing failures in many M3/M5’s." Last edited by Ngilbe36; 10-18-2017 at 07:58 AM.. |
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10-18-2017, 07:38 AM | #3206 |
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Wow, this guy is far from a tribology expert. His statement "All liquids are incompressible (that’s how hydraulics work, including brakes with their watery thin brake fluid), so it does NOT matter what the viscosity of any liquid is. Thick oil or thin oil will create the same incompressible liquid oil wedge." is 100% false.
Viscosity plays a large role in how the oil wedge in a hydrodynamic bearing behaves, especially "local" viscosity since there is a large temperature gradient in the oil wedge in a hydrodynamic bearing. Actual viscosity of the oil in the wedge is the primary fluid variable in the load carrying capacity of bearing. In fact, the use of high levels of polymer additives in wide-range multi-weight oils creates a non-Newtonian behavior of the oil which becomes especially important in the behavior (and load carrying capacity) of the oil film under high strain conditions. The normal linear relationship between strain rate and sheer stress of the oil becomes a non-linear relationship under high rates of strain whereby you see a fall off in viscosity with high strain rate -- which immediately comes back once the strain rate declines. This is the situation in the oil wedge of the bearing -- extreme rates of strain; hence localized viscosity is profoundly important to the successful operation and load carrying capacity of the bearing. I would strongly suggest the writer of the material spend some time studying Tribology prior to making such statements. A good reference is "Engineering Tribology" by Stachowiak and Batchelor.
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10-24-2017, 11:50 AM | #3207 | |
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We can at least address the rod bearings without a total tear-down... :|
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10-24-2017, 12:08 PM | #3208 | |
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02-26-2018, 03:01 PM | #3210 |
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02-27-2018, 10:44 AM | #3211 |
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03-12-2018, 06:34 PM | #3212 | |
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With supercharger On ORIGINAL BEARINGS WITH TRACK DAYS That's insane!! |
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