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09-27-2013, 10:58 AM | #89 |
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Has anyone thought about the reason BMW Chose 10w-60 when there is such a tight bearing clearance? Is it because it holds up better when you track the car often?
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09-27-2013, 12:02 PM | #91 | |
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Told me were way too tight for any engine, be it a street or race engine! Carillo rods for the S65 are made to BMW OEM dimensions on both width and bore size. If a custom rod dimension is required it must be requested. The choices made by BMW on these clearances are also quite odd! When I build a small displacement engine I look for between 0.012"-0.020" side clearance for a minimum but on the S65 and the fact that it revs so high I would be more comfortable with 0.020"-0.030". As for your bearing measurements, please tell me why you think that blue and red shells are the same thickness? Why would they have different colors and part numbers if they are exactly the same dimensions??? I would be more inclined to think your measurements were off rather than the bearings being the same thickness. To regular guy, GREAT JOB!!! Lots of info, well written and well organized! Sorry I haven't been participating in this great thread....... Between work, selling my current home and building a new one it is next to impossible to get a 1/2 hour to take in the forums! |
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09-27-2013, 02:02 PM | #92 |
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Kawasaki00, How do you feel about the MOTUL 300V 0w40 compared to the Castrol TWS 10w60 and the MOBIL 1 0W40? The MOTUL and MOBIL 1 seem very similar.
Viscosity grade SAE J 300 SAE 0W-40 Density at 20°C (68°F) ASTM D1298 0.848 Viscosity at 40°C (104°F) ASTM D445 75.7 mm²/s Viscosity at 100°C (212°F) ASTM D445 13.6 mm²/s HTHS viscosity at 150°C (302°F) ASTM D4741 3.9 mPa.s Viscosity Index ASTM D2270 186 Pour point ASTM D97 -51°C / -59.8°F Flash point ASTM D92 222°C / 431.6°F TBN ASTM D2896 8.25 mg KOH/g |
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09-27-2013, 02:03 PM | #93 | |
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My money is on both bearing being made of different material, hence the colour designations. |
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09-27-2013, 03:37 PM | #94 | ||||
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At the end of the day, the discussion of bearing thickness seems academic because the measurements aren't used to calculate bearing clearance. The only thing that matters is the clearance between the rod+bearing bore and the rod journal. Regardless, after making the bearing thickness measurements, we also placed red+red into a connecting rod, and torqued them before making proper bore/clearance measurements. This information was originally posted here: http://www.m3post.com/forums/showpos...&postcount=107 For red+blue: 2.0483 For red+red: 2.0486 Difference: 0.00030 Notice that difference matches our bearing thickness measurements quite well. BTW, lots of things affect bearing clearance, not just bearing thickness. Did you also measure this at the same time? |
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09-27-2013, 04:05 PM | #96 |
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Some people, me included were interested to see a comparison of these clearances specs to other engines. It is difficult to get access to that documentation for more recent engines so if you have something more recent by all mean provide that info but here are some older high performance engines. A few of these are by now historical cars but the clearance numbers cannot be questionned as they come straight from the corresponding manufacturer.
(and think metric) S65B40 (repeated for the comparison) Main Bearing Clearance [mm]: 0.0291 - 0.0458 Rod Bearing Clearance [mm]: 0.0293 - 0.0469 ----------------------------------------------- Ferrari Mondial 8/QV Main Bearing Clearance [mm]: 0.0290 - 0.0640 Rod Bearing Clearance [mm]: 0.0460 - 0.0890 (source: pages B11 and B19 in the 281/83 Mondial 8/QV WSM specs) Ferrari 328 GTS Main Bearing Clearance [mm]: 0.0130 - 0.0510 Rod Bearing Clearance [mm]: (source: Ferrari Technical Specs, Service bulletin, page 6, total 147 pages) Porsche 924 Main Bearing Clearance [mm]: 0.0200 - 0.0800 Rod Bearing Clearance [mm]: 0.0200 - 0.0700 (source Porsche engine specs) Porsche 912,911, 911T,911L,911S Main Bearing Clearance [mm]: 0.0100 - 0.0720 Rod Bearing Clearance [mm]: 0.0300 - 0.0880 (source Workshop Manual on E127) Main Bearing Clearance [mm]: 0.0300 - 0.0880 Rod Bearing Clearance [mm]: 0.0300 - 0.0880 (source 912,911, 911T,911L,911S Spec Book) I have not searched the rod side clearance specs for the above but doing a random search: Rod side clearance: 0.015 - 0.025 (inches) (source: Jim Smart Senior editor of Mustang & Ford monthly "Engine Tips - Biggest Engine-Building Mistakes") For information 2 hairs diameter is about 2 X 0.007 inches = 0.014 inches Based on these numbers the S65 engine main/rod bearing clearances are not out of family, they seem to fit right in with these other cars. Of course there are large differences between these cars and a whole set of parameters that would have to be adjusted for : surface harshness of main journals and bearings, surface finishing and treatment, materials, engine horsepower, max RPM, dynamic compression ratio, tune, etc. I will let the expert speak on that. Some engines have failed indeniably something went wrong but I think attributing the problem to the clearances does not seem to add up. It may be an aggravating factor but based on other engines clearances we are not there in terms of finding the root cause. Last edited by V8FunNaturally; 09-27-2013 at 04:27 PM.. |
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09-27-2013, 04:17 PM | #97 | |
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I'm with you on that. Last edited by Yellow Snow; 09-27-2013 at 04:23 PM.. |
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09-27-2013, 04:27 PM | #98 | |||
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BTW, do you mind if I figure out a way to incorporate your data into the table on the first page? |
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09-27-2013, 04:43 PM | #99 | |
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I seriously doubt these engines last past the warranty period or even past 10,000 miles if they had clearance issues. The amount of heat, pressure, and rpm of the parts in the engine would never last past the dyno if the clearance wasn't ideal (imo). I think there are other factors in play... type of oil, miles/time between oil changes, driving habits, climate.... No doubt people have failed motors and the bearings seem to be failing prematurely but my bet is the material of the bearing or oil passage has more to do with it.
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09-27-2013, 05:02 PM | #100 | |
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I am taking a machining class right now and just last class session, it was indicated by the prof and the book that the average diameter for a human hair is 0.003 inch. I would believe this is closer to what Regular Guy had in mind when he said 2 human hair. That would make the side clearance at 0.006 which is much smaller than the average of 0.015-0.030 that I randomly searched on. Last edited by e92zero; 09-27-2013 at 05:13 PM.. |
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09-27-2013, 07:29 PM | #101 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Now, before anybody wants to messenger, let me explain this. All I did was calculate the midpoint as "nominal" bearing clearance and did a very quick internet search to find the factory recommended oil. I took the first thing I could find. In the case of the Porsche, I found a factory manual online; and same for Ferrari 328. For the others, I found other internet postings that talked about factory oil specs. For S65B40, I also used the midpoint method to calculate nominal bearing clearance even though we know that's not correct. The actual nominal clearance values are those I posted in the first post and were determined by looking at two cranks and two sets of rods and selecting the values that came up the most often. For reference, actual nominal S65B40 is: Main Bearing Clearance: 0.03650 mm, 0.00144" Rod Bearing Clearance: 0.03250 mm, 0.00125" The point is: let's not roast the messenger. The idea is to make the data as accurate as possible without bias or agenda. If somebody finds more accurate data, I'll refine and revise the list. I will also add more engines to the list should the data become available:
Last edited by regular guy; 09-27-2013 at 07:43 PM.. |
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09-27-2013, 07:44 PM | #102 |
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I think its great your posting this....and its a great discussion. I just don't think its a clearance problem. There are people with 80-100k on their s65's with no failures. That wouldn't happen with a clearance problem that plagues all s65's. I think its really jumping the gun by taking a shop's opinion on clearances.
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09-27-2013, 09:59 PM | #103 | ||||
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09-27-2013, 10:45 PM | #104 | |
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The issue doesn't necessarily plague each and every S65, but it certainly seems like it affects most of them. The proof is in the pudding. There are lots of documented cases of premature bearing wear, there have been numerous engine failures as due to rod bearings seizing and the rod being thrown through the block. Take a good look at the measurements that regular guy has posted...... Do you see an issue? The biggest issue to me is the variance between rods. If a manufacturer wanted to build an engine tight like this and have it last, different bearing sizes should have been made to allow each rod to be dialled in more closely and have an even clearance across all of the eight rods. The Japanese manufacturers do this on even their run of the mill engines, it is not uncommon to see a corolla or civic with three or four different bearing colors. You don't just buy a set of bearings for them, you refer to your colors and put back in what came out. There is no doubt that the S65 has a bearing issue, and listening to a shop is definitely what I would do. Who would you listen to or trust? A manufacturer who has built engines that they had to recall due to clearance issues and seem to be having the same issues all over again? Or would you trust one of the premier engine builders in the world, an engine builder that gas built and designed engines for Indy cars, aircraft, sprint cars......... The list goes on! I know who I would trust! So the info is here, the facts are that BMW is going against the experience of all of us who build engines for a living, and against the bearing manufacturers recommendation regarding clearances and engine oil selection! Look at the facts again and see if you still feel the same way. |
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09-28-2013, 12:23 AM | #105 | |
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We're talking about measuring bearing thickness with a gauge calibrated to 0.001 mm resolution. The inside diameter of the bearing is approximately 52.00 mm. The accuracy of this measurement at that resolution depends on the needle landing exactly in the zero-degree mark of the bearing. If you miss the zero-degree mark by 1/20th of one degree, then your measurement will be off by 0.0035 mm on a 52mm ID bearing; that's 3.5 times the resolution we're trying to measure. To make this work at 0.001 mm resolution, your angle error can't be more than 3/200ths of a single degree (+/- 0.015 of a single degree). Call me a skeptic, but that doesn't seem possible with the technique shown in those pictures. Maybe I'm just unfamiliar with this technique and it's actually easier than it looks. But I'm definitely willing to ask the engine shop if they want to set me up and show me how to use that type of gauge. I've seen that type of gauge in the engine shop, so I know they have them. But it's going to take many weeks before I'll get a chance. |
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09-28-2013, 12:48 AM | #106 |
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I think this is the most overlooked aspect of this discussion. Nobody's saying that all engines have a problem; and nobody's saying that all engines are going to blow. At least, I'm not saying that. But I am looking for explanations for the actual data we see in real life. For example, why do so many bone stock engines fail with less than 25000 miles, but very few stock engines fail between 25000 to warranty expiration? That perplexes me.
So about a year+ ago, a few of us began to theorize that the cause was due to manufacturing variances. If you get an engine where everything is dead center of the tolerance range, then you will be fine. But if you get an engine that even has a single journal at the upper end of the tolerance range and matched with a rod that's at the bottom end of its tolerance range, and you have a recipe for an engine failure. That's been my theory for nearly a year now. But there was no way to know if this was true until I collected all of these measurements. If the measurements didn't show so much variance, I would have posted a slightly different article. I would have said: "Here's the measurements, and I didn't see anything wrong." But that's not how it played out. Instead, we looked there and found exactly what I feared we would find. But I realize this still proves nothing. I think of it as just another piece of data. Last edited by regular guy; 09-28-2013 at 01:23 AM.. |
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09-28-2013, 01:17 AM | #107 |
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Here's a set of bearings that should spark a good discussion. These are the bearings that came from the bone stock engine used for these measurements. These were "Crankshaft-1" journals, rods, and bearings. I've correlated the clearance measurements by cylinder number. This allows one to see the bearings that came from the cylinder with the least and most amount of clearance.
It's sure to spark some discussion, because the first thing I notice are the worst looking bearings coming from the cylinders with the largest bearing clearance. I've got to be honest, I don't quite understand that; but this is also the only engine I know that has correlated the clearance to the actual bearings. As we see more motors taken apart, that's when we'll know if this is the norm or the anomaly. S65, 30000 Miles, Bone Stock, 2008. More Photos Factory Bearings: 088/089 Category: 04/05-Moderate Description: Bone stock engine disassembled to make stroker motor. |
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09-28-2013, 02:26 AM | #108 | |
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09-28-2013, 02:29 AM | #109 | |
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This is a highly accurate way of measuring and surely better for your reference when comparing with other shops across the world than relying on someones mic feel. Your photo's are interesting and seem to indicate that clearance isn't necessarily the problem here. My theory is that the bearings are different material, hence the price difference between the two. Is it beyond the realms of possibility that some motors have been assembled with the wrong bearings top/bottom ie red top, blue bottom? Could you check part numbers or colours on a failed set? I know there have been a few bearing failures but percentage wise across the cars production it's a minute proportion. It's virtually unheard of in the UK. |
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09-28-2013, 06:38 AM | #110 | |
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I work for a company that rebuilds industrial, marine, truck and generator diesel engines. I've seen where a engine was assembled using the wrong sized bearings (believe it or not they were labeled wrong from the factory!..ouch). The engine didn't make it off the dyno. The bearings looked like these pictured and there was metal all through the engine/pan. I believe if this was a clearance issue, the failures would be more common and severe
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