Official S65 Bearing Specification/Clearance Wiki

[Billj747]

Originally Posted by e92zero

So the S65/S85 are the only engines where the max is outside the Clevite's recommendation and with thick oil? Does compression ratio matter to the force exerted on the rod bearings?

No, the E46, NSX, and S2000's main bearings' Max are all outside Clevite's recommendation. The S65/85 have both the rods and mains tighter.

I'm not a motor builder, but I would imagine the total compression in the cylinder (more for high compression and FI), the piston speed, RPM, stroke, rod ratio, etc... all affect the force exerted on the rod bearings.

I think there is a reason you typically see larger clearances for turbo cars.

[kawasaki00]

On top of rod bearings the longer the rod the greater the dwell time while the piston is at -10 to 10 degrees, it is much harder on the pin end of the rod and pin bores.
Thanks for all the info, the 30wts fit the specs of the honda motors nicely. Also notice how the 10-30 is relatively the same as the 0-40 nowadays.

[Billj747]

Originally Posted by kawasaki00

On top of rod bearings the longer the rod the greater the dwell time while the piston is at -10 to 10 degrees, it is much harder on the pin end of the rod and pin bores.
Thanks for all the info, the 30wts fit the specs of the honda motors nicely. Also notice how the 10-30 is relatively the same as the 0-40 nowadays.

So (with all things constant), a longer rod = less side load on the cylinder walls, lower piston speed at TDC, and greater the dwell time at -10 to 10 degrees which is harder on the pin end of the rod/pin bores?

How would a slower piston speed at TDC be harder on the pin? I would think it would be easier since change of direction for the piston at TDC is slower? But doesn't a longer dwell make better use of the combustion pressure and turning the pressure into torque, improving volumetric efficiency at higher rpms?

I know there's a lot more to the picture but I thought the longer the rod/higher the rod ratio makes for a higher revving motor? (A Toyota F1 engine has a 2.72:1 ratio but a tiny stroke):

http://www.motoiq.com/MagazineArticl...th-Matter.aspx

-Just asking for self-edification and understanding.

[e92zero]

Originally Posted by Billj747

No, the E46, NSX, and S2000's main bearings' Max are all outside Clevite's recommendation. The S65/85 have both the rods and mains tighter.

I'm not a motor builder, but I would imagine the total compression in the cylinder (more for high compression and FI), the piston speed, RPM, stroke, rod ratio, etc... all affect the force exerted on the rod bearings.

I think there is a reason you typically see larger clearances for turbo cars.

oops, my bad. I meant to say the max for the rod clearance are still outside the recommendation. Thanks for finding and listing the info.

[kawasaki00]

Originally Posted by Billj747

So (with all things constant), a longer rod = less side load on the cylinder walls, lower piston speed at TDC, and greater the dwell time at -10 to 10 degrees which is harder on the pin end of the rod/pin bores?

How would a slower piston speed at TDC be harder on the pin? I would think it would be easier since change of direction for the piston at TDC is slower? But doesn't a longer dwell make better use of the combustion pressure and turning the pressure into torque, improving volumetric efficiency at higher rpms?

I know there's a lot more to the picture but I thought the longer the rod/higher the rod ratio makes for a higher revving motor? (A Toyota F1 engine has a 2.72:1 ratio but a tiny stroke):

http://www.motoiq.com/MagazineArticl...th-Matter.aspx

-Just asking for self-edification and understanding.

A longer rod will speed to the top of the bore faster, hang out at the top longer and speed back down faster.
Imagine 1 second from bottom to top then back to bottom in another second in a linear pattern just for demo sake. Then put a longer rod in and it will get to almost the top faster then slow down across the top then speed back up and still be at the bottom of the bore at the same time. The longer the piston is at the top of the bore the longer the peak cylinder pressure is hammering the pin bore. It also makes it more fickle with what is called CA50 numbers, this is the number of cycles the peak cylinder pressure happen sooner than 4 degrees BTDC, this number is different for every cylinder also. This is why running different timing figures in each cylinder is normal for race engines. These numbers are only obtained with the usage of combustion analysis equipment either in car or running a entire race on a motoring dyno.
You must consider the bore size and overall stroke though relative to the F1 engine. It is not moving near as much mass as a normal engine because of the ultra small bore, hence they can get away with the higher ratio. The latest generation of F1 stuff might be a little difference but for many years our piston speeds were the highest in all of racing. Around 97ish feet per second.
I am sure if you look around a little bit you can find some college guy that already knows all this stuff and has this documentation though- There is my stab for the night

[jcolley]

Another S85 preventive based on BS report. ESS VT2 S/C, but not a failure.

http://www.m5board.com/vbulletin/e60...ml#post3984913

[MFL]

Originally Posted by jcolley

Another S85 preventive based on BS report. ESS VT2 S/C, but not a failure.

http://www.m5board.com/vbulletin/e60...ml#post3984913

I love how his repair is pushed back a week due to rod bolts being on BACKORDER. Nope, nothing to see here folks, move along.



I just hope my shit grenades before my warranty does!

[regular guy]

Here's some bearing photos from a 2012 M3. The original engine sustained motor damage and was replaced with a 2008 M3 engine. The 2008 engine was purchased as a short block with 27000 miles. Every inch of the short block was inspected and cleaned before fastening the cylinder heads from the 2012 engine. Before installing into the car, the engine was outfitted with an ESS VT2-625 Supercharger.

After 3000 miles of driving (when the engine had 30000 miles on it), a Blackstone oil report was taken that shows excessively high lead levels. A decision was made to replace the bearings. The bearing photos below were taken approximately 1000 miles after the Blackstone oil report.

Blackstone Oil Report:


S65, 31000 Miles, Naturally Aspirated, 2008. More Photos
Factory Bearings: 088/089
Category: 04-Moderate
Description: 27,000 Miles Naturally Aspirated, 4000 Miles Supercharged

1	2	3	4
5	6	7	8

[SenorFunkyPants]

Originally Posted by regular guy

Please explain your theory for fuel quality affecting bearing clearance and oil starvation.

To recap:
Poster A wonders why there are no known reports of bearing related engine failures in the UK
Poster B queries what could possibly cause that anomaly (in a rather arsey manner it must be said).
So: given that the UK market has the same engine, uses the same oil and the same service schedule the only variable is the fuel.
And in the UK there is no low octane fuel available (you can't buy 87 rated fuel)...our standard U/L fuel is equivalent to a USA rating of ~91 with equivalents of ~94 or ~95 available at most every station.
The question is: if you ran two identical cars, one using standard octane fuel and the other using low octane fuel for say 50,000 miles would you expect to find any significant difference in bearing wear between the 2 engines?
Talking into account the benefits of the antiknock sensors but tempered by the failure of at least one S/Ced engine attributed by the builder to the use of low octane fuel.

[kawasaki00]

Originally Posted by SenorFunkyPants

To recap:
Poster A wonders why there are no known reports of bearing related engine failures in the UK
Poster B queries what could possibly cause that anomaly (in a rather arsey manner it must be said).
So: given that the UK market has the same engine, uses the same oil and the same service schedule the only variable is the fuel.
And in the UK there is no low octane fuel available (you can't buy 87 rated fuel)...our standard U/L fuel is equivalent to a USA rating of ~91 with equivalents of ~94 or ~95 available at most every station.
The question is: if you ran two identical cars, one using standard octane fuel and the other using low octane fuel for say 50,000 miles would you expect to find any significant difference in bearing wear between the 2 engines?
Talking into account the benefits of the antiknock sensors but tempered by the failure of at least one S/Ced engine attributed by the builder to the use of low octane fuel.

I remember that thread about the blown engine with the guy running the low octane fuel. The lower the octane the faster it burns which adds timing, it is a snow ball deal, not only does it run leaner it also adds timing. Kaboom
So the lowest octane you guys have is 91 and the highest is 94, does it have ethanol in it?

[SenorFunkyPants]

Originally Posted by kawasaki00

So the lowest octane you guys have is 91 and the highest is 94, does it have ethanol in it?

Yep We have 95 Ron standard U/L equates to ~91 USA rated.
And Super U/L 97, 98 or 99 Ron - equates to ~93 to ~95 USA rated.
A quick check shows some brands include 5% Ethanol in standard U/L while others don't...Most super U/L brands are Ethanol free. Upcoming changes in EU regulations may see this change sometime soon.
Its rare to come across a UK M3 owner who doesn't put Super U/L in their car - our fuel is already so expensive that a few more pennies for the good stuff doesn't make much difference.

[thekurgan]

Originally Posted by regular guy

Here's some bearing photos from a 2012 M3. The original engine sustained motor damage and was replaced with a 2008 M3 engine. The 2008 engine was purchased as a short block with 27000 miles. Every inch of the short block was inspected and cleaned before fastening the cylinder heads from the 2012 engine. Before installing into the car, the engine was outfitted with an ESS VT2-625 Supercharger.

After 3000 miles of driving (when the engine had 30000 miles on it), a Blackstone oil report was taken that shows excessively high lead levels. A decision was made to replace the bearings. The bearing photos below were taken approximately 1000 miles after the Blackstone oil report.

So these are bearings from the '08 motor and not the '12 motor? I wonder when the new bearing material went into production. I'd like to see a set of those with some mileage too, that would be sweet.

[GIdriver]

Originally Posted by thekurgan

So these are bearings from the '08 motor and not the '12 motor? I wonder when the new bearing material went into production. I'd like to see a set of those with some mileage too, that would be sweet.

+1

[kawasaki00]

Originally Posted by regular guy

Blackstone Oil Report:


S65, 31000 Miles, Naturally Aspirated, 2008. More Photos
Factory Bearings: 088/089
Category: 04-Moderate
Description: 27,000 Miles Naturally Aspirated, 4000 Miles Supercharged

A few of those look like the housing bore is not straight, especially number 4 and 7

[regular guy]

Originally Posted by SenorFunkyPants

To recap:
Poster A wonders why there are no known reports of bearing related engine failures in the UK

Actually Poster-A reframed the question from oil clearance, oil starvation, and bearing wear into "known reports of bearing related engine failures...in the UK." The entire premise of the question was invalid to begin with. Poster-A has also been playing pretty fast and loose by making up clearance specs that don't exist and issuing challenges to explain failures on the S54 that he couldn't back up because he didn't have the data. So any information and queries posted by Poster-A needs to be questioned and tested before they can be trusted at face value.

Poster B queries what could possibly cause that anomaly (in a rather arsey manner it must be said).

I'd say it was far less arsey than the way I was asked what's the best outcome of this thread...followed by a big assumption with a highly opinionated comment.

But let's get back to the real question here...something that you didn't address.

So: given that the UK market has the same engine, uses the same oil and the same service schedule the only variable is the fuel.
And in the UK there is no low octane fuel available (you can't buy 87 rated fuel)...our standard U/L fuel is equivalent to a USA rating of ~91 with equivalents of ~94 or ~95 available at most every station.
The question is: if you ran two identical cars, one using standard octane fuel and the other using low octane fuel for say 50,000 miles would you expect to find any significant difference in bearing wear between the 2 engines?

What is your hypothesis as it relates to gasoline octane rating for the failure of low mileage, bone stock engines? Are you suggesting a design flaw at BMW if the engines can't withstand the gasoline they were designed and tested to run on?

I'd also like to know your hypothesis for a gasoline octane connection to rod bearing photos that match the Clevite photos of too little bearing clearance causing oil starvation (found in Clevite online bearing failure web site, example #12).

You said yourself "Any sensible debate has to be argued from both sides. If the assertions can't withstand aggressive scrutiny then what are they worth?" So let's hear your explanation of both questions.

Talking into account the benefits of the antiknock sensors but tempered by the failure of at least one S/Ced engine attributed by the builder to the use of low octane fuel.

I think you're talking about the guy who ran a car rally in SoCal then suffered an engine failures on the way home. That SC failuire was a kit design to run exclusively on 93 octane. If that's the one, it was bought by a guy in California who ran it on 91 octane even after being repeatedly warned via email not to run 91 octane. Then after ignoring the warnings, he filled up with 87 octane and the engine went kaboom. I'm failing to see a connection to this thread at all and that situation. Please explain that too.

[SenorFunkyPants]

Firstly I will declare scant knowledge of bearing clearance etc. (the last engine/gearbox/diff rebuilds I did was on a 1967 Mini Cooper S with my Dad back in the day).
So this is from a more logic based position.
When BMW were designing/building the first S65 engines I think its fair to presume that they didn't give a couple of interns a S85 engine, a hacksaw and ask for a V8 to be up and running by the time they got back from the pub!
BMW would have data on wear and failure rates for the S85 and would logically take the opportunity to make improvements for reliability in the S65.
So what changes were made: AFAICT A change to the oil lubrication system and to the Vanos design, a significant upgrade to the ECU and to the knock sensing system seem to be the headline changes.
So, BMW having had all of the S85 engines that failed in the field returned to them for strip down and analysis, didn't make changes to the bearings and clearances (despite having ample opportunities) when designing the S65. Instead they concentrated on improving the knock sensing system aided by a new ECU some 8 times faster than the one used on the S85. That would suggest that BMW thought that protection from poor fuel quality was an important reliability upgrade.
So to my query: "if you ran two identical cars, one using standard octane fuel and the other using low octane fuel for say 50,000 miles would you expect to find any significant difference in bearing wear between the 2 engines?"
The reason I included mention of the S/Ced engine is that it (apparently) failed due to low octane fuel >>despite<< the S65s sophisticated anti knock system.
This not to say that bearing clearance isn't a problem, maybe just not all of the problem.

[Yellow Snow]

Originally Posted by regular guy

Actually Poster-A reframed the question from oil clearance, oil starvation, and bearing wear into "known reports of bearing related engine failures...in the UK." The entire premise of the question was invalid to begin with. Poster-A has also been playing pretty fast and loose by making up clearance specs that don't exist and issuing challenges to explain failures on the S54 that he couldn't back up because he didn't have the data. So any information and queries posted by Poster-A needs to be questioned and tested before they can be trusted at face value.



I'd say it was far less arsey than the way I was asked what's the best outcome of this thread...followed by a big assumption with a highly opinionated comment.

You really are quite obnoxious. How old are you?

[whats77inaname]

Originally Posted by Yellow Snow

You really are quite obnoxious. How old are you?

Oh the irony.....

[Cool Steel]

Before I weed through all of this information I was hoping that there is someone kind enough to briefly give us a consensus agreed upon recommendation ?
Different oil? Oil additive? etc.

If tearing apart the engine is the solution and getting new bearings and connecting rods...than it time for me to trade in and get a Challenger SRT8....lol

I understand their is a bearing issues, however, like another poster mentioned, all high performance engines have problems. The mustang Coyote 5.0 is having problems in their cylinder #8....so we are not alone...I am hoping that this is just in hard driven cars...??
http://www.modularfords.com/threads/...linder-Failure

[regular guy]

Originally Posted by thekurgan

So these are bearings from the '08 motor and not the '12 motor?

Correct.

I wonder when the new bearing material went into production. I'd like to see a set of those with some mileage too, that would be sweet.

I believe it went into production in Oct-2008 because that's when the main bearings changed. But we've seen engines into 2011 with the older 088/089 bearings. So it's really hard to tell if they just used the 088/089's until they ran out of stock or not.

[regular guy]

Originally Posted by Yellow Snow

You really are quite obnoxious. How old are you?

I never wanted this thread to be treated like a medical journal with scientific peer review. But that's what it got turned into. I intended this thread to be written for the layperson, so the layperson could understand. Instead of trusting each other at their word, we ended up pointing out every flaw because that's what was brought into the thread. I realize it sounds obnoxious, but this is how we got here.

I do know of blown motors in the UK. But blown motors only leave pieces of evidence behind, where rod bearing photos give you clues that you can use to put the pieces back together. I've got pictures of three blown motors from the last 4 months. The rods snapped and shot out the block and/or oil pan. Each blown motor has one thing in common: the rod big end suffered tremendous heat damage; they were beyond turning blue. That heat is caused by friction. I can't really prove what caused the friction, but I can look at the bearing photos and see the evidence to see too little oil clearance. Whatever the cause, the rod got super heated and most likely siezed the journal and snapped the rod before shooting out the block. The bearing photos are your best clues to see too little clearance. All you need to do after that is put the rest of the pieces of the puzzle together and you have a good working hypothesis for what's causing these motors to blow.

BTW, I'm old enough to have seen Frank Zappa in concert three times.

Originally Posted by whats77inaname

Oh the irony.....

Quite.

[regular guy]

Originally Posted by SenorFunkyPants

Firstly I will declare scant knowledge of bearing clearance etc. (the last engine/gearbox/diff rebuilds I did was on a 1967 Mini Cooper S with my Dad back in the day).

So this is from a more logic based position.

When BMW were designing/building the first S65 engines I think its fair to presume that they didn't give a couple of interns a S85 engine, a hacksaw and ask for a V8 to be up and running by the time they got back from the pub!

I like that...pretty funny jab at my earlier comments. Well done sir!

BMW would have data on wear and failure rates for the S85 and would logically take the opportunity to make improvements for reliability in the S65.

So what changes were made: AFAICT A change to the oil lubrication system and to the Vanos design, a significant upgrade to the ECU and to the knock sensing system seem to be the headline changes.

For an engine, the design cycles are very long. For electronics, they are even longer, and for engine electronics, probably even longer than that. I believe the S65 was designed and etched in stone before the S85 ever hit production. The VANOS changes were made out of necessity, not because BMW learned something along the way. Here's how BMW themselves described the VANOS changes for the S65:

In the S85, the VANOS high pressure pump is installed instead of the S65 oil return pump, and the S85 oil return pump is contained in a housing together with the main oil pump (tandem pump).

Since there is no space to install a tandem pump in the S65, the oil return pump has been moved from the main oil pump housing and installed instead of the VANOS highpressure pump.

So, BMW having had all of the S85 engines that failed in the field returned to them for strip down and analysis, didn't make changes to the bearings and clearances (despite having ample opportunities) when designing the S65. Instead they concentrated on improving the knock sensing system aided by a new ECU some 8 times faster than the one used on the S85. That would suggest that BMW thought that protection from poor fuel quality was an important reliability upgrade.

My company provides electronics for many automotive applications. I can't tell you who we work with, but you might be familiar with our work. Our designs are chosen about six years in advance of production. For engine electronics that involve vehicle and passenger safety, I'll bet it's even longer than six years, probably closer to eight. Don't forget, these engine electronics must pass a rigorous safety regimen and multi-government certification before they are ever placed into production. This means the MSS60 wasn't an afterthought of lessons learned on the MSS65, but was likely designed and undergoing certification at least a year or two before the E60-M5 ever went into production.

I can't prove any of that, but if you just work the manufacturing design cycle backwards, those are the kind of dates that come up.

So to my query: "if you ran two identical cars, one using standard octane fuel and the other using low octane fuel for say 50,000 miles would you expect to find any significant difference in bearing wear between the 2 engines?"

Maybe Kawasaki can answer that, I can't. If I saw evidence in these photos that said most failures occurred in places that only had 91 octane, I'd say it's something to look at closer. But many of these photos are coming from the eastern US and Canada where they run 93 and 94 octane. So to me, the evidence doesn't suggest a connection to fuel.

The reason I included mention of the S/Ced engine is that it (apparently) failed due to low octane fuel >>despite<< the S65s sophisticated anti knock system.

This not to say that bearing clearance isn't a problem, maybe just not all of the problem.

The case of the SC motor was running 87 octane fuel. 87 octane is well below the minimum the engine was designed to run. 91 octane is not.

I read online once that there's a type of detonation near bottom dead center that is especially destructive to bearings. Once I read that, I've never been able to find the article again. Maybe Kawasaki can shed some light on that topic to say if it's true or pure BS.