bearing issue: overestimation?

[gatorfast]

Originally Posted by regular guy

Meaning this...

The factory clearances may be on the small side, but just big enough that nominal crank journal diameter mated with nominal rod bearing bore diameter will result in a relatively long running engine (albeit with crappy looking bearings every time you take them apart and inspect them). The tolerance stack up I mentioned happens when you take a crank journal that is at the upper end of the journal size specification and gets mated with a connecting rod bearing bore that is at the lower end of its specification. Those engines don't last past the first 25000 miles. That's the tolerance stack up that I was talking about. I think it's a pretty reasonable explanation for just about everything we've seen so far: 1) low mileage motors that go boom; 2) almost all engines that will last a reasonably long time; but 3) all the bearings will still look like crap when you take them out and inspect them.

Makes sense. Thanks for the explanation.

[M3-S65]

Originally Posted by regular guy

Meaning this...

The factory clearances may be on the small side, but just big enough that nominal crank journal diameter mated with nominal rod bearing bore diameter will result in a relatively long running engine (albeit with crappy looking bearings every time you take them apart and inspect them). The tolerance stack up I mentioned happens when you take a crank journal that is at the upper end of the journal size specification and gets mated with a connecting rod bearing bore that is at the lower end of its specification. Those engines don't last past the first 25000 miles. That's the tolerance stack up that I was talking about. I think it's a pretty reasonable explanation for just about everything we've seen so far: 1) low mileage motors that go boom; 2) almost all engines that will last a reasonably long time; but 3) all the bearings will still look like crap when you take them out and inspect them.

I love you guys...so in other words the worst case scenario
I wonder how often this worst case scenario occurs?...worst case scenarios are typically a low probability occurrence. However, is it too soon to assume this?.. I wonder, will we see in the future that this is not a worst case (with a low probability) but instead a problem that takes time to evolve?? ...Keep your warranty...too much thinking need a beer.

[bigjae1976]

Originally Posted by regular guy

Meaning this...

The factory clearances may be on the small side, but just big enough that nominal crank journal diameter mated with nominal rod bearing bore diameter will result in a relatively long running engine (albeit with crappy looking bearings every time you take them apart and inspect them). The tolerance stack up I mentioned happens when you take a crank journal that is at the upper end of the journal size specification and gets mated with a connecting rod bearing bore that is at the lower end of its specification. Those engines don't last past the first 25000 miles. That's the tolerance stack up that I was talking about. I think it's a pretty reasonable explanation for just about everything we've seen so far: 1) low mileage motors that go boom; 2) almost all engines that will last a reasonably long time; but 3) all the bearings will still look like crap when you take them out and inspect them.

Agree with you there.

Although I did see one 2011 E90 with 38k miles at COTA have a really weird knocking noise but it sounded like it came from the top end. Not sure what came of it.

I did use M1 0W-40 over the winter and did not rev the car much past 5k rpm. $26 for 5qts at Walmart. WIN! Going back to Castrol 10W-60 for the summer in 2 weeks...only if winter would ever f'ing end!

[regular guy]

Originally Posted by swamp2

Since this hasn't been tested or observed in any fashion whatsoever, I believe it is worth pointing out that this it pure speculation. Your post, especially to one not familiar with the discussion make it sounds like you have a large certainty about cause, effect and observation here.

Bearing tolerances would also contribute to overall tolerance stacking in addition to crank and rod bores.

Your existing measurements, IIRC, tired to mix and match sizes to get a worst case scenario for bearing clearance and the newer bearings were still within a generally accepted minimum. The measurements also showed really minimal manufacturing variation in some cases testing the limits of your equipment. Those particular observations don't really support your hypothesis.

Now this minor criticism aside, I too think it is a reasonable explanation. It sure would be good to have much more measurement data as that could really help lead one down the path to your conclusion.

Thank you Captain Obvious for pointing out for the 85th time that none of us can do failure analysis on engines that go back to BMW as part of a warranty replacement. I would bet even a 10 year-old could grasp that concept after the 84th time you've said it in the 45th thread you've decided to make a name for yourself.

There is much more fertile ground on the forum for your nit picking expertise than following me around in every thread just so you can repeat yourself. Might I suggest you follow some of the tuners who claim great expertise. Look into some of their posts and see if you find them as vacuous and lacking technical accuracy as I do. I look forward to your posts to correct their "plethora of errors."

BTW, anybody who has to repeatedly point out how important they are and talk about how many thanks they get "behind the scenes..." is neither important nor getting a fraction of the thanks as they would lead everybody to believe.

[MKE_M3]

Originally Posted by bigjae1976

Agree with you there.

Although I did see one 2011 E90 with 38k miles at COTA have a really weird knocking noise but it sounded like it came from the top end. Not sure what came of it.

I did use M1 0W-40 over the winter and did not rev the car much past 5k rpm. $26 for 5qts at Walmart. WIN! Going back to Castrol 10W-60 for the summer in 2 weeks...only if winter would ever f'ing end!

From a fellow Wisconsinite, I feel your pain. I'm still riding on winter tires

[bigjae1976]

Originally Posted by regular guy

Thank you Captain Obvious for pointing out for the 85th time that none of us can do failure analysis on engines that go back to BMW as part of a warranty replacement.

Don't feed the troll...but I can't help myself.

Originally Posted by MKE_M3

From a fellow Wisconsinite, I feel your pain. I'm still riding on winter tires

Just took mine off right after the snow storm earlier this week.

[gazosnic]

I always ask as well and hear the same thing. He s65 is the most reliable and no bearing issues. I think it's an overblown issue on the forums as we seeing the small % of cars that have forced induction and are pushed very hard.

[swamp2]

Originally Posted by regular guy

Thank you Captain Obvious for pointing out for the 85th time that none of us can do failure analysis on engines that go back to BMW as part of a warranty replacement. I would bet even a 10 year-old could grasp that concept after the 84th time you've said it in the 45th thread you've decided to make a name for yourself.

There is much more fertile ground on the forum for your nit picking expertise than following me around in every thread just so you can repeat yourself. Might I suggest you follow some of the tuners who claim great expertise. Look into some of their posts and see if you find them as vacuous and lacking technical accuracy as I do. I look forward to your posts to correct their "plethora of errors."

BTW, anybody who has to repeatedly point out how important they are and talk about how many thanks they get "behind the scenes..." is neither important nor getting a fraction of the thanks as they would lead everybody to believe.

Yawn...

Talk about the pot calling the kettle black. You too could stop repeating the same old speculation on post after post...

I'm interested in potential problems in our (my) car as much as the next guy. If you think I "follow you around" online, you've got more of an ego problem than you accuse me of.

It's really simple. You make bold claims and make them sounds like they have a shred of proof when they don't. Thus I feel many of your posts can use some clarification. If you don't want to hear from me (or for some strange reason don't want others to) use more clear and accurate language and qualify your positions. Call it nitpciking if you like, I'm also highly interested in the truth.

As to interest in debating vendors, I do some of that as well. However, folks know a bit better when dealing with them that there is inherently a significant amount of advertisement.

I'd be happy to PM you many "thank you" messages I have received on this bearing topic. It does mean my point of view makes sense and is even occasionally compelling enough to warrant such messages. I know you too have received thanks for your investigation, spending, time and attention to detail on the subject. Neither effort is more or less important.

[swamp2]

Originally Posted by bigjae1976

Don't feed the troll...

Sorry buddy but the real troll here is the one making such nonsense accusations. Lay off the ridiculous ad hominems.

[regular guy]

Originally Posted by swamp2

Yawn...

Talk about the pot calling the kettle black. You too could stop repeating the same old speculation on post after post...

I'm interested in potential problems in our (my) car as much as the next guy. If you think I "follow you around" online, you've got more of an ego problem than you accuse me of.

It's really simple. You make bold claims and make them sounds like they have a shred of proof when they don't. Thus I feel many of your posts can use some clarification. If you don't want to hear from me (or for some strange reason don't want others to) use more clear and accurate language and qualify your positions. Call it nitpciking if you like, I'm also highly interested in the truth.

As to interest in debating vendors, I do some of that as well. However, folks know a bit better when dealing with them that there is inherently a significant amount of advertisement.

I'd be happy to PM you many "thank you" messages I have received on this bearing topic. It does mean my point of view makes sense and is even occasionally compelling enough to warrant such messages. I know you too have received thanks for your investigation, spending, time and attention to detail on the subject. Neither effort is more or less important.

I don't share private messages, nor do I believe anybody should without permission. Nobody likes a troll, a stalker, or anybody who violates another's privacy. And I don't like (once again) reminding you to quit putting false words into my mouth. (Notice any type of theme here?)

The real irony is when you said at the end: "I too think it is a reasonable explanation." So in this case, I made a huge bold claim without a shred of proof...yet you agree with it anyways...and want to argue about it all at the same time.

[bigjae1976]

Originally Posted by swamp2

Sorry buddy but the real troll here is the one making such nonsense accusations. Lay off the ridiculous ad hominems.

I'm starting a new thing...I will only communicate with you in smilies.

[swamp2]

Originally Posted by regular guy

I don't share private messages, nor do I believe anybody should without permission. Nobody likes a troll, a stalker, or anybody who violates another's privacy. And I don't like (once again) reminding you to quit putting false words into my mouth. (Notice any type of theme here?)

The real irony is when you said at the end: "I too think it is a reasonable explanation." So in this case, I made a huge bold claim without a shred of proof...yet you agree with it anyways...and want to argue about it all at the same time.

What exactly did I say that put false words in your mouth?

There isn't much irony here. You describe a situation using strong language that makes it sound very much like a theory supported by observation (even using specific (yet completely arbitrary) data like a mileage range). I claim it is a reasonable hypothesis, but still unsupported by any data whatsoever.

By the way I was not offering sharing of anything that would violate the inherent privacy of a PM. It should be painfully obvious that this is possible.

[swamp2]

Originally Posted by bigjae1976

I'm starting a new thing...I will only communicate with you in smilies.

What a fun game, I'll lower myself to your level as well.

[aus]

Originally Posted by gazosnic

I always ask as well and hear the same thing. He s65 is the most reliable and no bearing issues. I think it's an overblown issue on the forums as we seeing the small % of cars that have forced induction and are pushed very hard.

The problem is, if its your engine that blows, it's 100% you need a new engine, and there's no warning until its too late. Particularly with the newer bearings, where no one seems to know what to look for on oil analysis.

.