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      10-16-2019, 06:34 PM   #45
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Quote:
Originally Posted by hlm2c View Post
Mr. "Tons of SCH on M2Cs", thats only 1 M2C. And in that case, if you over-rev, that's user error. You're lucky the crankhub even spun and did its job and protected your transmission and/or engine so they didn't blow up as a result. You fail to provide actual data, only rumours. To this date, like others have mentioned, there have only been two reported cases amongst the hundreds/thousands of M2Cs produced. That is less than 1%. Please come back when you have actual proof, thanks.
Great point. We've seen close to zero here at the dealership.

Certainly no "tons."
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      10-16-2019, 11:22 PM   #46
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Originally Posted by ChrisK View Post
That's hard to watch.
Yeah that's really painful to watch, it always is better to take that extra split second for a shift to ensure that this never happens.
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      10-17-2019, 11:03 PM   #47
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Well, it’s a bit ridiculous how sensitive this engine is. I mean, it gives me, a prospective buyer next to zero confidence in the car I’m about to drop $60K on..

Absurd this hasn’t been addressed. That video was painful.
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      10-17-2019, 11:50 PM   #48
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The crazy part is the ///M curse continues. E46 M3 subframe issues and rod bearings, E9X M3 rod bearing issues, F8X S55 crank hub issues. 3 generations of M3's now all with crazy flaws.
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      10-18-2019, 07:25 AM   #49
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Originally Posted by F87source View Post
I think they only showed a couple of broken cranks.

No I don't trust VTT either but I wanted to point out there that a new vendor who wants to market their product by bashig someone else's work while copying VTT's crank bolt capture probably is fishy.

Honestly imo it's hard to trust any vendor on this issue especially after tpg screwed everyone over with their sub par product as documented in the thread I linked earlier.
Not sure who came up with the crank bolt capture but there are 10s of retailers that sell it now.

BTW you would think that if this solution works (or any of them really) BMW would have implemented it, its 5-10E tops worth of materials and labour in an OEM setting.

Also cracking a crank is "easy" if you wedge something big enough in there. Kinda like splitting a log with wedge. This does not prove that the splines "lock". Which brings another issue, the splines could cause the hub to bottom out before it is supposed to therefore not sandwiching the remaining gear (the timing one I think) tightly enough...

It would be simple enough to make a rig that lets you measure relative slip torques, yet I have not seen a single pic from any aftermarket vendor with such a rig.

Hell give me a crank + crankhub + gears etc and ill make one.

Totally agree with the vendor aspect, its seems some guys are sales people 1st and mechanics/engineers second.


Quote:
Originally Posted by F87source View Post
The crazy part is the ///M curse continues. E46 M3 subframe issues and rod bearings, E9X M3 rod bearing issues, F8X S55 crank hub issues. 3 generations of M3's now all with crazy flaws.
Every engineered product has "flaws" if you flog it hard enough for long enough.

The above video is user error, can't use a stick properly? get a DCT

The SCH is over exagerated IMHO, and not half as bad as the previous M weaknesses
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      10-18-2019, 09:16 AM   #50
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Quote:
Originally Posted by Megator View Post
Quote:
Originally Posted by F87source View Post
I think they only showed a couple of broken cranks.

No I don't trust VTT either but I wanted to point out there that a new vendor who wants to market their product by bashig someone else's work while copying VTT's crank bolt capture probably is fishy.

Honestly imo it's hard to trust any vendor on this issue especially after tpg screwed everyone over with their sub par product as documented in the thread I linked earlier.
Not sure who came up with the crank bolt capture but there are 10s of retailers that sell it now.

BTW you would think that if this solution works (or any of them really) BMW would have implemented it, its 5-10E tops worth of materials and labour in an OEM setting.

Also cracking a crank is "easy" if you wedge something big enough in there. Kinda like splitting a log with wedge. This does not prove that the splines "lock". Which brings another issue, the splines could cause the hub to bottom out before it is supposed to therefore not sandwiching the remaining gear (the timing one I think) tightly enough...

It would be simple enough to make a rig that lets you measure relative slip torques, yet I have not seen a single pic from any aftermarket vendor with such a rig.

Hell give me a crank + crankhub + gears etc and ill make one.

Totally agree with the vendor aspect, its seems some guys are sales people 1st and mechanics/engineers second.


Quote:
Originally Posted by F87source View Post
The crazy part is the ///M curse continues. E46 M3 subframe issues and rod bearings, E9X M3 rod bearing issues, F8X S55 crank hub issues. 3 generations of M3's now all with crazy flaws.
Every engineered product has "flaws" if you flog it hard enough for long enough.

The above video is user error, can't use a stick properly? get a DCT

The SCH is over exagerated IMHO, and not half as bad as the previous M weaknesses
Agreed, the S55 is bulitproof compared to the bearing BS of my s65 e92 M3.
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      10-18-2019, 10:47 AM   #51
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Quote:
Originally Posted by Megator View Post
Not sure who came up with the crank bolt capture but there are 10s of retailers that sell it now.

BTW you would think that if this solution works (or any of them really) BMW would have implemented it, its 5-10E tops worth of materials and labour in an OEM setting.

Also cracking a crank is "easy" if you wedge something big enough in there. Kinda like splitting a log with wedge. This does not prove that the splines "lock". Which brings another issue, the splines could cause the hub to bottom out before it is supposed to therefore not sandwiching the remaining gear (the timing one I think) tightly enough...

It would be simple enough to make a rig that lets you measure relative slip torques, yet I have not seen a single pic from any aftermarket vendor with such a rig.

Hell give me a crank + crankhub + gears etc and ill make one.

Totally agree with the vendor aspect, its seems some guys are sales people 1st and mechanics/engineers second.




Every engineered product has "flaws" if you flog it hard enough for long enough.

The above video is user error, can't use a stick properly? get a DCT

The SCH is over exagerated IMHO, and not half as bad as the previous M weaknesses
IIRC some guy on the forum for the crank bolt capture before anyone made anything and collabed or sold the design to VTT (can't remember), but VTT was first. Apparently according to VTT in another thread the company ordered a few sets from them but it was out of stock or something and they got upset and knocked it off.


They probably won't implement a fix because they know the S55 is near the end of its life and if they do fix it they'll have to accept there's an issue and issue a mass recall which is extremely costly, vs. just fixing the issues that do pop up which are low in frequency. It's just like how suabru knows they have brittle and weak pistons on the ej257 that can fail stock but still retain the same design for 20 years, because it's cheaper to fix issues that pop up than fix them all.

Well the cranks crack because somethjng is preventing the friction disc from slipping, so if everything else is keep the same it should be the spline lock. I do agree they need to publish more data but what are you going to do right? Also yeah I heard about the splines not letting it seat properly but VTT said something about they designed the splines to allow it to seat blah blah blah, whether or not that's legit I don't know, but so far the ones in circulation (even on high powered cars) don't seem to be leaking or having oil gear issues so it should be ok? Again I don't know we'll need more data before we can may a conclusion.



Yeah that video was driver error, it sucked to see.


It still shouldn't spin, the Crank hub issues is a shit BMW design. Although the issue isn't as bad as the previous ones it's still bad since the fixes are extremely intrusive and so far they all (from what I know) seem to have some issues.
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      10-18-2019, 10:56 AM   #52
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Quote:
Originally Posted by F87source View Post
IIRC some guy on the forum for the crank bolt capture before anyone made anything and collabed or sold the design to VTT (can't remember), but VTT was first. Apparently according to VTT in another thread the company ordered a few sets from them but it was out of stock or something and they got upset and knocked it off.


They probably won't implement a fix because they know the S55 is near the end of its life and if they do fix it they'll have to accept there's an issue and issue a mass recall which is extremely costly, vs. just fixing the issues that do pop up which are low in frequency. It's just like how suabru knows they have brittle and weak pistons on the ej257 that can fail stock but still retain the same design for 20 years, because it's cheaper to fix issues that pop up than fix them all.

Well the cranks crack because somethjng is preventing the friction disc from slipping, so if everything else is keep the same it should be the spline lock. I do agree they need to publish more data but what are you going to do right? Also yeah I heard about the splines not letting it seat properly but VTT said something about they designed the splines to allow it to seat blah blah blah, whether or not that's legit I don't know, but so far the ones in circulation (even on high powered cars) don't seem to be leaking or having oil gear issues so it should be ok? Again I don't know we'll need more data before we can may a conclusion.



Yeah that video was driver error, it sucked to see.


It still shouldn't spin, the Crank hub issues is a shit BMW design. Although the issue isn't as bad as the previous ones it's still bad since the fixes are extremely intrusive and so far they all (from what I know) seem to have some issues.
Interesting to hear the history, I was not so interested in the details of the S55 till I owned one

Check this out BTW https://f80.bimmerpost.com/forums/sh...546386&page=11

I worked in "fixing" engineering issues and you are right, not every known issue gets fixed. BMW must have calced that not doing anything is the most cost effective solution. B58 hub is different... (well partially because it is at the back of the engine and has to take all the TQ), but don't want to be stuck with a VANOS or chain guide bill haha.
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      10-18-2019, 01:52 PM   #53
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Quote:
Originally Posted by Megator View Post
Interesting to hear the history, I was not so interested in the details of the S55 till I owned one

Check this out BTW https://f80.bimmerpost.com/forums/sh...546386&page=11

I worked in "fixing" engineering issues and you are right, not every known issue gets fixed. BMW must have calced that not doing anything is the most cost effective solution. B58 hub is different... (well partially because it is at the back of the engine and has to take all the TQ), but don't want to be stuck with a VANOS or chain guide bill haha.
Yeah I heard that the ECU and crank position sensor was sensitive enough to save the motor, and if you had a hub fix and it spun it would take the whole motor. But if a stock hub spins it can still take the motor out since the ECU and crank position sensor doesn't retard timing in time for all cases, then piston meets valve.
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      10-19-2019, 09:20 AM   #54
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It's nothing to do with retarding timing..

The DME is sensitive enough to detect a small hub slip. So you get limp mode before hub slip is enough to cause valve piston contact.

This gives you notice to take care and get it to the workshop.

But if you have a large slip nothing can stop valve contact.
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      10-19-2019, 01:44 PM   #55
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Originally Posted by doughboy View Post
It's nothing to do with retarding timing..

The DME is sensitive enough to detect a small hub slip. So you get limp mode before hub slip is enough to cause valve piston contact.

This gives you notice to take care and get it to the workshop.

But if you have a large slip nothing can stop valve contact.
Yes that's right, my mistake I'm conditioned at theoment to associate limp mode with pulling timing since I was talking to some guys about a supercharged frs where there is no boost control from the ECU, and the failsafe is for timing to be pulled when there's knock.

But limp mode is a condition where waste gates open which means no boost, and ignition timing is pulled. Among this Valvetronic is probably disabled too.
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Last edited by F87source; 10-19-2019 at 01:59 PM..
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      10-21-2019, 06:30 AM   #56
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But if you have a large slip nothing can stop valve contact.
Which is why a money shift like the vid takes out the motor. The H2 guys stripped it down and there had been contact.

I wonder if DCTs have less severe hub slips.
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      10-21-2019, 07:17 AM   #57
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Quote:
Originally Posted by Megator View Post
Which is why a money shift like the vid takes out the motor. The H2 guys stripped it down and there had been contact.

I wonder if DCTs have less severe hub slips.
Of course you can't money shift a DCT, but that aside a DCT is much more violent in its engine rpm steps than any sensible manual driver would be.

So perhaps DCT is more likely to slip but then less likely to big slip like a manual money shift?

Back to that money shift video, I just don't know how he did it - does he have super strong arms that can crash a gearbox into gear when the syncros are blocking it?

What does he do? top end of 4th into 3rd? Just a bad operator at the controls. You push/pull a gear stick with a bit of care and wait/feel for the 'box to give you the next gear, anyone who just smashes into gear like that is asking for trouble...
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      10-21-2019, 08:18 AM   #58
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Quote:
Originally Posted by doughboy View Post
Of course you can't money shift a DCT, but that aside a DCT is much more violent in its engine rpm steps than any sensible manual driver would be.

So perhaps DCT is more likely to slip but then less likely to big slip like a manual money shift?

Back to that money shift video, I just don't know how he did it - does he have super strong arms that can crash a gearbox into gear when the syncros are blocking it?

What does he do? top end of 4th into 3rd? Just a bad operator at the controls. You push/pull a gear stick with a bit of care and wait/feel for the 'box to give you the next gear, anyone who just smashes into gear like that is asking for trouble...
I was trying to figure this one out too. Looked like a shift to 3rd was next but he went to 1st? Seems that would require some serious slamming.
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      10-21-2019, 08:21 AM   #59
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If only the possibility was limited to money shifts. It’s not, far from it.
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      10-21-2019, 09:57 AM   #60
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Does the crank hub issue, about high rpm ?

If so , how that possible with DCT cars?
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      10-21-2019, 10:56 AM   #61
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Quote:
Originally Posted by armiii View Post
Does the crank hub issue, about high rpm ?

If so , how that possible with DCT cars?
Quote:
Originally Posted by armiii View Post
Does the crank hub issue, about high rpm ?

If so , how that possible with DCT cars?
shock to drivetrain. DCT shifts harder than 6sp especially when kickdown is used.
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      10-21-2019, 01:52 PM   #62
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Originally Posted by Kuervers View Post
shock to drivetrain. DCT shifts harder than 6sp especially when kickdown is used.
With both my M2 and M2C, I still haven't used the kickdown.
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      10-22-2019, 03:47 AM   #63
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shock to drivetrain. DCT shifts harder than 6sp especially when kickdown is used.
Can you explain this in more detail?
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      10-22-2019, 01:56 PM   #64
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Just found BMS has a "Downshift Blocker" to physically stop the throttle before engaging kickdown. Interesting, might be a handy little device if someone wants to feel more comfortable with a DCT.
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      10-22-2019, 05:03 PM   #65
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Quote:
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Can you explain this in more detail?
Kickdown is a feature on the DCT. At the end of the accelerator pedal there is a resistance point, if you push past that point it activates the lowest gear possible based on engine RPM. So if you are cruising around in 7th it can drop 2-3 gears almost immediately and in some cases pretty violently. There is a theory that this happens so fast and strongly that it could knock the crank hub out of place.

Us 6MT guys/gals worry less about it since we'd have to either shift at speeds that wouldn't be practical, unless of course you money shift. Which unfortunately, is what one poor soul did. It's probably not the only way to spin the crank hub, but it makes sense. Luckily I think the problem is overblown as it sounds like there has been 1 known (to us) failure that wasn't a money shift.

If you are cautious like me, you can get mechanical breakdown insurance if your car is less than a year old. I think you can keep it on for 100k miles. In my case, for about 90/year I'm covered if my crank hub decides to loosen up. Seems reasonable for an engine that could cost over 20k to replace.
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      10-23-2019, 05:13 AM   #66
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Originally Posted by pz619 View Post
Kickdown is a feature on the DCT. At the end of the accelerator pedal there is a resistance point, if you push past that point it activates the lowest gear possible based on engine RPM. So if you are cruising around in 7th it can drop 2-3 gears almost immediately and in some cases pretty violently. There is a theory that this happens so fast and strongly that it could knock the crank hub out of place.

Us 6MT guys/gals worry less about it since we'd have to either shift at speeds that wouldn't be practical, unless of course you money shift. Which unfortunately, is what one poor soul did. It's probably not the only way to spin the crank hub, but it makes sense. Luckily I think the problem is overblown as it sounds like there has been 1 known (to us) failure that wasn't a money shift.

If you are cautious like me, you can get mechanical breakdown insurance if your car is less than a year old. I think you can keep it on for 100k miles. In my case, for about 90/year I'm covered if my crank hub decides to loosen up. Seems reasonable for an engine that could cost over 20k to replace.
that sounds ridiculous to me,why bmw does not create something for protection?
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