Official S65 Bearing Specification/Clearance Wiki

[swamp2]

Originally Posted by BMRLVR

You are just now entering this discussion and telling me that you expect better of me?!
...

When I enter the discussion is relevant how exactly?

It's great of you to clarify your experience. Again, it clearly helps make you a great forum contributor and an M owner who knows more than the vast majority. However, I still stick by my statement that you are involved in an entirely different realm of engines and you have no direct engineering experience. Working with engineers for a prototype simply is not engine design. Nor is it tribology the relevant engineering sub discipline here. Yes all engines have bearnings and bearing clearances, this is for sure but the heavy, noisy and low rpm world is very different than the S65...

You also did not answer my question yet... It would be great to know your answer:

Agree or disagree, my rewording of your statement is more accurate accounting of your hypothesis?

By the way, I've seen enough here to change my oil immediately and go with a thinner oil. Nothing wrong with being conservative. That being said I still firmly believe we have a hypothesis here and there is fully contradictory evidence to the hypothesis. Not exactly a 100% kind of situation...

Cheers.

[regular guy]

Originally Posted by swamp2

When I enter the discussion is relevant how exactly?

It's great of you to clarify your experience. Again, it clearly helps make you a great forum contributor and an M owner who knows more than the vast majority. However, I still stick by my statement that you are involved in an entirely different realm of engines and you have no direct engineering experience. Working with engineers for a prototype simply is not engine design. Nor is it tribology the relevant engineering sub discipline here. Yes all engines have bearnings and bearing clearances, this is for sure but the heavy, noisy and low rpm world is very different than the S65...

You also did not answer my question yet... It would be great to know your answer:

Agree or disagree, my rewording of your statement is more accurate accounting of your hypothesis?

By the way, I've seen enough here to change my oil immediately and go with a thinner oil. Nothing wrong with being conservative. That being said I still firmly believe we have a hypothesis here and there is fully contradictory evidence to the hypothesis. Not exactly a 100% kind of situation...

Cheers.

Please take the Q&A to PM's so this thread can stay on track without getting closed. I'm now looking through my notes to see if I can cobble together a second set of correlated measurements to bearing photos. Hopefully I can.

[regular guy]

Here's a second set of (semi) correlated bearing photos. I call them "semi-correlated" because the actual journal diameters are no longer available, but the bearing bore measurements are all still available. Instead, the build notes do give the nominal journal diameter and actual rod bearing bore diameter. So these are semi-correlated measurements because the nominal journal diamter was stacked up with the actual bearing bore diameter to calculate the bearing clearance.

Cylinder	1	2	3	4
Clearance	0.0254 mm / 0.00100 inch	0.0254 mm / 0.00100 inch	0.0279 mm / 0.00110 inch	0.0305 mm / 0.00120 inch
Photo
Photo
Clearance	0.0305 mm / 0.00120 inch	0.0305 mm / 0.00120 inch	0.0330 mm / 0.00130 inch	0.0356 mm / 0.00140 inch
Cylinder	5	6	7	8

Granted this is completely unscientific, which to some will imply the correlation is meaningless. But even as unscientific as it might be, there does seem to be some correlation with small clearance to worst looking bearings. The only exception is cylinder-8, which has moderate bearing wear and the best clearance (using unscientific methods). But for the other cylinders, the small clearance correlates to the worst looking bearings.

[kawasaki00]

I will just say it was nice talking to Ludwig Willisch when he was in our shop the other week.

[Yellow Snow]

Isn't that oil spec sheet just for the top up oils, not the full oil change?

[BMRLVR]

Originally Posted by swamp2

When I enter the discussion is relevant how exactly?

It's great of you to clarify your experience. Again, it clearly helps make you a great forum contributor and an M owner who knows more than the vast majority. However, I still stick by my statement that you are involved in an entirely different realm of engines and you have no direct engineering experience. Working with engineers for a prototype simply is not engine design. Nor is it tribology the relevant engineering sub discipline here. Yes all engines have bearnings and bearing clearances, this is for sure but the heavy, noisy and low rpm world is very different than the S65...

You also did not answer my question yet... It would be great to know your answer:

Agree or disagree, my rewording of your statement is more accurate accounting of your hypothesis?

By the way, I've seen enough here to change my oil immediately and go with a thinner oil. Nothing wrong with being conservative. That being said I still firmly believe we have a hypothesis here and there is fully contradictory evidence to the hypothesis. Not exactly a 100% kind of situation...

Cheers.

All I meant by you "just" entering the discussion is the fact that myself, kawasaki00, and regular guy have been discussing this subject on the forums at length for months now. We have been involved in technical discussions, measuring and documentation (thanks to regular guy and his access to various S65's and connections at one of the best engine builders in NA), and virgin and used oil testing (thanks to kawasaki00 and his access to a cutting edge shop and equipment), and discussion with Clevite regarding bearings (again thanks to kawasaki00).

As for me being involved in a different area of engines, that is correct, and you are also correct in the fact that I am not an engineer, but I think you overestimate the differences between the engine types and their designs. The technical training regarding engines is basically the same regardless of displacement. I am not limited to working on large diesel engines, my license and technical training qualifies and allows me to work on any engine regardless of displacement or fuel type. Please explain to me the major differences in the engines I work on from an engineering and design standpoint compared to an engine like the S65. I look forward to what you have to say.

So to answer your question, I do agree with most of it but don't agree "totally" with the rewording of my statement, and here is why: I do agree that BMW chose tighter clearances by design, and I also agree that production variances are causing even tighter clearances in some cases. What I don't agree with is the fact that in the bearings with tighter clearances there is oil starvation...... The reality in my opinion, is that even their design spec is too tight and starvation and cavitation is occurring in bearings within their specified clearance range. This combined with their curiously heavy oil spec is leading to the bearing wear in the S65.

Finally I agree with the fact that there is a "hypothesis" and not a 100% solution due to lack of testing with different clearances and documentation of said testing. I guess I feel that past practice of engine building with clearances that are known to work are enough for me. That in a way is like engineering, you don't reinvent the wheel when you don't have to, you just go with what is known to work unless you are faced with a problem that has to be engineered to work due to lack options to use known ways to accomplish the task. In the S65, adequate clearances were possible, and BMW didn't need to reinvent the wheel here......... To put my money where my mouth is, I am building my stroker with clearances that are known to work, in a few years I will let you know if that was the right or wrong decision.

To finish, here is some food for thought: Steve Dinan is an engineer and Dinan no doubt employees many other engineers. When building their S85 and S65 strokers, they chose to open up the clearances on the mains and rods to something very close to the industry accepted average. Do you think this is coincidence?!

As per regular guys request, I won't continue the back and forth on here since this thread is to be a home for information and testing regarding the S65 bearing issue. Please feel free to PM me if you want to discuss this further.

[Yellow Snow]

RG. Have you done any comparison measurements against a 2mm slip gauge yet?

Kawasaki: any news on the hardness testing between top and bottom halves?

[kawasaki00]

Originally Posted by Yellow Snow

RG. Have you done any comparison measurements against a 2mm slip gauge yet?

Kawasaki: any news on the hardness testing between top and bottom halves?

They are all finished, I will post up the info tomorrow.

[aus]

Originally Posted by kawasaki00

I will just say it was nice talking to Ludwig Willisch when he was in our shop the other week.

Please do share!!!

.

[regular guy]

Originally Posted by Yellow Snow

RG. Have you done any comparison measurements against a 2mm slip gauge yet?

Kawasaki: any news on the hardness testing between top and bottom halves?

I sent the bearings to Kawasaki, so all I now have are beat up, used ones. I told Kawasaki he could run destructive tests on the bearings, so I doubt I'll see them back. We'll see when he posts his findings if he measured thicknesses with some of his better equipment.

[swamp2]

Originally Posted by regular guy

Please take the Q&A to PM's so this thread can stay on track without getting closed. I'm now looking through my notes to see if I can cobble together a second set of correlated measurements to bearing photos. Hopefully I can.

I'm not participating in a Q&A and I don't feel the discussion belongs in PM. Regardless I see NOTHING about my participation here that would even hint toward a thread closure. I'm sorry you do feel this way.

I often hark back to one of my favorite quotes by the famous late Astronomer, Carl Sagan who said, "Extraordinary claims require extraordinary evidence". I believe this applies here in the way many are simply positive that BMW has made a mistake or oversight. Also in this case I'm sure there isn't a theory or even a statistically significant problem.

Yes, feel free, call me a skeptic, that's fine. I'll happily admit to that whether or not a firm theory is established. Even if you, BMRLVR and kawasaki00 are correct it does not mean my skepticism is or will be judged in the future as unwarranted.

Either way certainly keep up the good work. Someone has to do it and get to the bottom of this. I'm always thrilled to see the dedication of our community in matters like this.

[swamp2]

Originally Posted by BMRLVR

As for me being involved in a different area of engines, that is correct, and you are also correct in the fact that I am not an engineer, but I think you overestimate the differences between the engine types and their designs. The technical training regarding engines is basically the same regardless of displacement. I am not limited to working on large diesel engines, my license and technical training qualifies and allows me to work on any engine regardless of displacement or fuel type. Please explain to me the major differences in the engines I work on from an engineering and design standpoint compared to an engine like the S65. ...

...

To finish, here is some food for thought: Steve Dinan is an engineer and Dinan no doubt employees many other engineers. When building their S85 and S65 strokers, they chose to open up the clearances on the mains and rods to something very close to the industry accepted average. Do you think this is coincidence?!

The question here is two fold. It is not just about actual engineering experience (perhaps vs. field experience/rebuilding experience/race engine building experience/etc.) but who has experience with fundamentals of the load ratings, strength of materials, machine dynamics and tribology to SPECIFY clearances in major engine bearings for a clean sheet design. I think NO ONE you've mentioned have this, regardless of them being an engineer or not. Sure anyone can take a rule of thumb of this many thousandths per inch and make it work but where did this rule come from - the DESIGN ENGINEERS. Those who did the really hard, critical and analytical work on the topic. Heck I was a Mechanical Engineer for many years myself but I am not qualified in the least bit to come up with an original specification for something like this AND justify it.

[kawasaki00]

Originally Posted by swamp2

The question here is two fold. It is not just about actual engineering experience (perhaps vs. field experience/rebuilding experience/race engine building experience/etc.) but who has experience with fundamentals of the load ratings, strength of materials, machine dynamics and tribology to SPECIFY clearances in major engine bearings for a clean sheet design. I think NO ONE you've mentioned have this, regardless of them being an engineer or not. Sure anyone can take a rule of thumb of this many thousandths per inch and make it work but where did this rule come from - the DESIGN ENGINEERS. Those who did the really hard, critical and analytical work on the topic. Heck I was a Mechanical Engineer for many years myself but I am not qualified in the least bit to come up with an original specification for something like this AND justify it.

We do this every day, we design, test and make almost everyone of our own parts. The parts we do not make such as bearings and valve springs we design in house and have other manufacturers make them for us. I cant get into too many details but alot of the latest and greatest things you see on performance cars (production) is passed down from our r&d department.

We do everything on our complex that you just stated you doubt anyone does.

[L4ces]

As a follower of this thread and M3 owner let me say Swamp, you're healthy skepticism is appreciated. Kawasaki00, Regular guy, your knowledge and experience is appreciated (same for Bmwlvr, Malek and others). And those who just ask good questions (Img, aus, and others ) that I wish I knew to ask.

All of you are needed to help many if not most of us make informed decisions and get educated. Sometimes, things get a little touchy, but you guys responses in doubts and disagreements have been so far respectful. Some other threads have gotten out of hand. IMHO, this one has not. You all show that you have knowledge to share. So continue with healthy doubts, research and all that sh1t.

[lsmkr01]

Originally Posted by kawasaki00

I will just say it was nice talking to Ludwig Willisch when he was in our shop the other week.

I wonder what the purpose of his visit was...

Originally Posted by kawasaki00

We do this every day, we design, test and make almost everyone of our own parts. The parts we do not make such as bearings and valve springs we design in house and have other manufacturers make them for us. I cant get into too many details but alot of the latest and greatest things you see on performance cars (production) is passed down from our r&d department.

We do everything on our complex that you just stated you doubt anyone does.

Glad to have you on the boards. This weekend is going to be very nice in our area. Any nice roads up your way? 387 from Cola to Myrtle is awesome but out of the way for both of us. I'm also itching to swap out the 10W-60 for M1 0W-40 even though I only have about 3k one the current oil.

[4corners]

Originally Posted by regular guy

Here's a second set of (semi) correlated bearing photos. I call them "semi-correlated" because the actual journal diameters are no longer available, but the bearing bore measurements are all still available. Instead, the build notes do give the nominal journal diameter and actual rod bearing bore diameter. So these are semi-correlated measurements because the nominal journal diamter was stacked up with the actual bearing bore diameter to calculate the bearing clearance.



Granted this is completely unscientific, which to some will imply the correlation is meaningless. But even as unscientific as it might be, there does seem to be some correlation with small clearance to worst looking bearings. The only exception is cylinder-8, which has moderate bearing wear and the best clearance (using unscientific methods). But for the other cylinders, the small clearance correlates to the worst looking bearings.

I don't know s**t about engineering but something crosses my mind when I look at the wear pattern on the upper bearing. Typically it is two spots directly below where the forces would be greatest from combustion.

If the rod was not stiff enough or rigid, could the rounded shape of the rod be distorted by the piston pushing down hard on the rod?

[B767capt]

[QUOTE=lsmkr01;14780415]I wonder what the purpose of his visit was...



So that Kawasaki could school him on proper rod bearing clearance.

[DLSJ5]

Originally Posted by kawasaki00

We do this every day, we design, test and make almost everyone of our own parts. The parts we do not make such as bearings and valve springs we design in house and have other manufacturers make them for us. I cant get into too many details but alot of the latest and greatest things you see on performance cars (production) is passed down from our r&d department.

We do everything on our complex that you just stated you doubt anyone does.

[W///]

[QUOTE=B767capt;14780936]

Originally Posted by lsmkr01

I wonder what the purpose of his visit was...



So that Kawasaki could school him on proper rod bearing clearance.

Hahaha bam!

[kawasaki00]

[QUOTE=lsmkr01;14780415]I wonder what the purpose of his visit was...
QUOTE]

[QUOTE=B767capt;14780936]

Originally Posted by lsmkr01

I wonder what the purpose of his visit was...



So that Kawasaki could school him on proper rod bearing clearance.

[QUOTE=W///;14781196]

Originally Posted by B767capt

Hahaha bam!

There are more people reading these boards than what you think.

[W///]

[QUOTE=kawasaki00;14781279][QUOTE=lsmkr01;14780415]I wonder what the purpose of his visit was...
QUOTE]

[QUOTE=B767capt;14780936]

Originally Posted by W///

There are more people reading these boards than what you think.

If they ask... I'm not running M1, nor does my car have a tune, or is dropped with aftermarket springs.

[kawasaki00]

[QUOTE=W///;14781291][QUOTE=kawasaki00;14781279][QUOTE=lsmkr01;14780415]I wonder what the purpose of his visit was...
QUOTE]

Originally Posted by B767capt

If they ask... I'm not running M1, nor does my car have a tune, or is dropped with aftermarket springs.

The M1 is approved now anyway so that doesnt matter anymore.