BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
M2 Technical Topics > S55 Engine / Drivetrain / Exhaust / Bolt-ons / Tuning > MY 2018+ s55 crank hub issue

Post Reply
 
Thread Tools Search this Thread
      10-12-2019, 02:53 PM   #23
F87source
Captain
F87source's Avatar
Canada
225
Rep
717
Posts

Drives: 2017 Bmw M2 6mt
Join Date: Aug 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by 1mm2 View Post
Odd, my dealer has had none yet two oils cooler punctures (M4s).
Same here, I've asked and they haven't had any m2C spun crank hubs and there are alot of M2C's where I live, and the dealerships are all owned by the same car conglomerate. Also alot of oil cooler failures probably because of the crappy post winter roads, and the fact that no one knows how to drive a low car in my area.
__________________
Follow me on Instagram @f87source
Appreciate 0
      10-12-2019, 02:54 PM   #24
1mm2
Lieutenant
354
Rep
522
Posts

Drives: M2
Join Date: Mar 2014
Location: Northern exposure

iTrader: (0)

Quote:
Originally Posted by F87source View Post
Hahaha I guess it is nice not to see the huge muffler.
A lot of my friends don't seem bothered by it, maybe I'm too just picky...
Appreciate 1
F87source224.50

      10-12-2019, 03:04 PM   #25
hlm2c
Private
United_States
53
Rep
85
Posts

Drives: M2C
Join Date: Dec 2018
Location: Korea

iTrader: (0)

Quote:
Originally Posted by BroDoze View Post
Yet you provide nothing. Zip. Nada.
Feel free to provide something of value here.
Likewise pal. Come back when you have evidence to your farfetched claims.
Appreciate 0
      10-12-2019, 04:28 PM   #26
BroDoze
Captain
70
Rep
682
Posts

Drives: Stuff
Join Date: Nov 2009
Location: Colorado

iTrader: (0)

^^ I did. Can you not read?
I mentioned actual data. What have you provided besides worthless broken-record posts.
Appreciate 0
      10-13-2019, 09:05 AM   #27
Tricki
Lieutenant
Tricki's Avatar
Australia
162
Rep
524
Posts

Drives: BMW M2 Comp
Join Date: Jun 2012
Location: Melbourne Australia

iTrader: (0)

Ive added the Crank Hub Bolt Capture to my car and to date i haven't heard of a slip with this in place.
A cause is the bolt to back out by the aggressive down gearing especially when tuned in D3 transmission setting.... ( my take )
Ive also added CS transmission flash and it down shifts fantastic and bearly past 4k revs, compared to stock at 6+k revs jolting the car back and possibly putting stress on the Crank Hub.
Appreciate 0
      10-14-2019, 10:28 AM   #28
Megator
Second Lieutenant
71
Rep
202
Posts

Drives: M2 Competition
Join Date: Mar 2019
Location: NL

iTrader: (0)

Quote:
Originally Posted by chris719 View Post
BMW definitely has this data. BMW very likely has probability distribution graphs of the torque required to spin the friction washer. You'll never see it and they will never admit there is an issue with some engines.
BMW will not have 100% accurate data of which cars failed and why. Trust me I have been the engineer responsible for similar things at different companies and the data we get back from the field is usually pants unless management wants a full investigation into a topic. Even then you are dependent on competent diagnosis and people going back to BMW and not their independent shop.

If BMW does not just use a table to design the bolted joint then I agree with you that they will have some kind of probability distribution of the bolted joint pre-load and friction force and hence how many are prone to failure.

I remember testing cylinder head joints and being surprised how great the preload spread could be between the same style of bolts, torqued by the same guy, in the same way.
Appreciate 0
      10-14-2019, 11:20 AM   #29
nearwater4me
Private
59
Rep
84
Posts

Drives: '20 BMW M2C
Join Date: Sep 2019
Location: KY

iTrader: (0)

Quote:
Originally Posted by Megator View Post
BMW will not have 100% accurate data of which cars failed and why. Trust me I have been the engineer responsible for similar things at different companies and the data we get back from the field is usually pants unless management wants a full investigation into a topic. Even then you are dependent on competent diagnosis and people going back to BMW and not their independent shop.

If BMW does not just use a table to design the bolted joint then I agree with you that they will have some kind of probability distribution of the bolted joint pre-load and friction force and hence how many are prone to failure.

I remember testing cylinder head joints and being surprised how great the preload spread could be between the same style of bolts, torqued by the same guy, in the same way.
Interesting read. Thanks.
I wish we had some kind of analysis showing the designed/intended load on the hub and the calculated safety factor.
As an engineer, Iím sure you are aware of how many anomalies you see in the field that just doesnít make sense.
Appreciate 0
      10-15-2019, 10:55 AM   #30
armiii
New Member
1
Rep
19
Posts

Drives: 2019 M2C
Join Date: Aug 2019
Location: republic

iTrader: (0)

I'm asking forgive me, can bmw solve this issue with a software upgrade?
Appreciate 0
      10-15-2019, 02:25 PM   #31
F87source
Captain
F87source's Avatar
Canada
225
Rep
717
Posts

Drives: 2017 Bmw M2 6mt
Join Date: Aug 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by armiii View Post
I'm asking forgive me, can bmw solve this issue with a software upgrade?
Likely no since this is a hardware issue. There has been speculation the dct shifts down so fast that it exacerbates the issue (so unless they completely destroy the way the dct shifts), likely it can't be fixed via software.

Also there has also been speculation that it's due to more things on the s55 being run off of the timing chain such as the water pump and two hpfps vs. 1.
__________________
Follow me on Instagram @f87source
Appreciate 0
      10-15-2019, 02:40 PM   #32
cntzl
Brigadier General
cntzl's Avatar
United_States
4354
Rep
3,496
Posts

Drives: 2019 M2C 6MT
Join Date: Mar 2015
Location: San Mateo, CA

iTrader: (0)

Quote:
Originally Posted by BroDoze View Post
Stock M2C (downshift overrev)
Downshift overrev, aka money shift which can happen to any manual car due to user error whether it's stock or tuned.
Appreciate 0
      10-16-2019, 05:21 AM   #33
armiii
New Member
1
Rep
19
Posts

Drives: 2019 M2C
Join Date: Aug 2019
Location: republic

iTrader: (0)

Quote:
Originally Posted by cntzl View Post
Downshift overrev, aka money shift which can happen to any manual car due to user error whether it's stock or tuned.
Appreciate 0
      10-16-2019, 07:45 AM   #34
ChrisK
Major General
ChrisK's Avatar
United_States
3587
Rep
7,167
Posts

Drives: '19 M2C
Join Date: Jun 2007
Location: Chicagoland (West)

iTrader: (6)

Garage List
Quote:
Originally Posted by armiii View Post
Quote:
Originally Posted by cntzl View Post
Downshift overrev, aka money shift which can happen to any manual car due to user error whether it's stock or tuned.
That's hard to watch.
__________________
www.ReTuneTheDeTune.com
2019 M2 Competition (Sunset Orange)
Appreciate 0
      10-16-2019, 08:35 AM   #35
Megator
Second Lieutenant
71
Rep
202
Posts

Drives: M2 Competition
Join Date: Mar 2019
Location: NL

iTrader: (0)

Quote:
Originally Posted by Tricki View Post
Ive added the Crank Hub Bolt Capture to my car and to date i haven't heard of a slip with this in place.
A cause is the bolt to back out by the aggressive down gearing especially when tuned in D3 transmission setting.... ( my take )
Ive also added CS transmission flash and it down shifts fantastic and bearly past 4k revs, compared to stock at 6+k revs jolting the car back and possibly putting stress on the Crank Hub.
You are miss-understanding the failure mode here. The preload on the joint is reduced first then the bolt may back out as the joint becomes looser and looser.

Think of the bolt as a spring. When it is tightened down it is stretched and pinches all the components together. If one of the components moves or compresses the height of the pinched components changes which also changes the bolt's stretch and the amount of pinch force it applies. As soon as you are below a threshold the bolt no longer applies sufficient pinch force to keep the joint together and all the parts spinning together. Each time the bolt can apply less and less preload exacerbating the problem and eventually it backs out.

The hub capture solution is dubious, the only thing it does is link the rotation of the bolt to the crank hub.

However the crank hub is still only fixed to the crank by the bolt threads and bolt preload. The timing gear and oil gear are sandwiched in there and still free to spin with respect to the bolt, hub, and crank. If the gears spin they will remove the preload and allow the whole of the hub and bolt to back out. The crank hub capture does not increase the preload / clamping force on the oil and timing gears!

The only thing the crank hub capture does is not allow the hub to spin with respect to the bolt. The only thing driven by the hub are the accessories (alternator, AC comp, etc). So if the accessory load is what causes the spun crank hub then the bolt capture is a possible solution, but this seems unlikely.

I think the reason no (reported) captured cars have failed is that 1) these cars are put back together with a lot of care and hence will fall into spec and not be outliers and 2) the failure numbers are relatively small anyways and the number of captured cars even smaller (and those on forums willing to share even less), so it is likely we would not hear about a failed one.

The only solution is to key a one piece hub / gear combo to the crank as Gintani does. Considering the cost of this solution and the fact most spun hubs do not cause much damage I personally will take the gamble and deal with it when it spins.

https://www.realoem.com/bmw/enUS/sho...diagId=11_5597
https://www.realoem.com/bmw/enUS/sho...diagId=11_5626

PS this is not meant as an attack on you merely info I am spreading

EDIT: Some further food for thought, my previous car a MK3 Focus RS had a similar crank hub design.

1) I money shifted it once. Was going for fourth coming out of a chicane at Zolder and got 2nd. Saw over 8k rpm (6.5k redline) on the tacho, car went into limp home mode till I restarted it several times --> no spun crank hub!
2) When carrying out the head gasket recall (common issue, about a year after the money shift) I got the car back with a spun crank hub (dealer swore they timed it right)! This issue is so rare on the Focus RS I no of no other cases of it happening. It was due to the poor reassembly on Ford's side and the fact they reused the crush washer holding it all together (equivalent to part 6 in the 1st link):

Last edited by Megator; 10-16-2019 at 08:43 AM..
Appreciate 1
      10-16-2019, 09:12 AM   #36
1mm2
Lieutenant
354
Rep
522
Posts

Drives: M2
Join Date: Mar 2014
Location: Northern exposure

iTrader: (0)

Quote:
Originally Posted by Megator View Post

The only solution is to key a one piece hub / gear combo to the crank as Gintani does. Considering the cost of this solution and the fact most spun hubs do not cause much damage I personally will take the gamble and deal with it when it spins.
This is it, until warranty expires.

Then maybe review Gintani solution if keeping long term.
Appreciate 0
      10-16-2019, 09:48 AM   #37
armiii
New Member
1
Rep
19
Posts

Drives: 2019 M2C
Join Date: Aug 2019
Location: republic

iTrader: (0)

Quote:
Originally Posted by Megator View Post
You are miss-understanding the failure mode here. The preload on the joint is reduced first then the bolt may back out as the joint becomes looser and looser.

Think of the bolt as a spring. When it is tightened down it is stretched and pinches all the components together. If one of the components moves or compresses the height of the pinched components changes which also changes the bolt's stretch and the amount of pinch force it applies. As soon as you are below a threshold the bolt no longer applies sufficient pinch force to keep the joint together and all the parts spinning together. Each time the bolt can apply less and less preload exacerbating the problem and eventually it backs out.

The hub capture solution is dubious, the only thing it does is link the rotation of the bolt to the crank hub.

However the crank hub is still only fixed to the crank by the bolt threads and bolt preload. The timing gear and oil gear are sandwiched in there and still free to spin with respect to the bolt, hub, and crank. If the gears spin they will remove the preload and allow the whole of the hub and bolt to back out. The crank hub capture does not increase the preload / clamping force on the oil and timing gears!

The only thing the crank hub capture does is not allow the hub to spin with respect to the bolt. The only thing driven by the hub are the accessories (alternator, AC comp, etc). So if the accessory load is what causes the spun crank hub then the bolt capture is a possible solution, but this seems unlikely.

I think the reason no (reported) captured cars have failed is that 1) these cars are put back together with a lot of care and hence will fall into spec and not be outliers and 2) the failure numbers are relatively small anyways and the number of captured cars even smaller (and those on forums willing to share even less), so it is likely we would not hear about a failed one.

The only solution is to key a one piece hub / gear combo to the crank as Gintani does. Considering the cost of this solution and the fact most spun hubs do not cause much damage I personally will take the gamble and deal with it when it spins.

https://www.realoem.com/bmw/enUS/sho...diagId=11_5597
https://www.realoem.com/bmw/enUS/sho...diagId=11_5626

PS this is not meant as an attack on you merely info I am spreading

EDIT: Some further food for thought, my previous car a MK3 Focus RS had a similar crank hub design.

1) I money shifted it once. Was going for fourth coming out of a chicane at Zolder and got 2nd. Saw over 8k rpm (6.5k redline) on the tacho, car went into limp home mode till I restarted it several times --> no spun crank hub!
2) When carrying out the head gasket recall (common issue, about a year after the money shift) I got the car back with a spun crank hub (dealer swore they timed it right)! This issue is so rare on the Focus RS I no of no other cases of it happening. It was due to the poor reassembly on Ford's side and the fact they reused the crush washer holding it all together (equivalent to part 6 in the 1st link):

can you simply explain this to me?
Appreciate 0
      10-16-2019, 10:23 AM   #38
F87source
Captain
F87source's Avatar
Canada
225
Rep
717
Posts

Drives: 2017 Bmw M2 6mt
Join Date: Aug 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by 1mm2 View Post
This is it, until warranty expires.

Then maybe review Gintani solution if keeping long term.
TBH the vtt spline lock solution sounds promising too, plus you don't have to pull the motor apart to the same extent for drilling the crank.
__________________
Follow me on Instagram @f87source
Appreciate 0
      10-16-2019, 11:06 AM   #39
Megator
Second Lieutenant
71
Rep
202
Posts

Drives: M2 Competition
Join Date: Mar 2019
Location: NL

iTrader: (0)

Quote:
Originally Posted by armiii View Post
can you simply explain this to me?
Not without being face to face (or me drawing a pretty picture). However maybe try a little experiment. Take a bolt (preferably of a bigish diameter) and stack a bunch of flat washers on it, then tighten them all using a nut (barely tight, just enough so the washers do not move). Now spin/move the washers without spinnig the nut (this might be hard to do but the more washers you have the easier it should be to do the middle ones), eventually you should be able to get the nut to come off without needing tools.

Essentially this is what is happening with the crank hub.

Quote:
Originally Posted by F87source View Post
TBH the vtt spline lock solution sounds promising too, plus you don't have to pull the motor apart to the same extent for drilling the crank.
Spline lock has been proven not to work. Great idea but the crank is forged and hardened you are never going to "bite" into the material by screwing something on.

Aside from that it seems their machinist might not be of the highest quality, see here:

https://www.litchfieldmotors.com/blo...ank-hub-issue/
Appreciate 1
      10-16-2019, 11:23 AM   #40
Detoxified
Enlisted Member
23
Rep
43
Posts

Drives: M2C HS
Join Date: Jun 2019
Location: SoCal

iTrader: (0)

Quote:
Originally Posted by Megator View Post
Quote:
Originally Posted by Tricki View Post
Ive added the Crank Hub Bolt Capture to my car and to date i haven't heard of a slip with this in place.
A cause is the bolt to back out by the aggressive down gearing especially when tuned in D3 transmission setting.... ( my take )
Ive also added CS transmission flash and it down shifts fantastic and bearly past 4k revs, compared to stock at 6+k revs jolting the car back and possibly putting stress on the Crank Hub.
You are miss-understanding the failure mode here. The preload on the joint is reduced first then the bolt may back out as the joint becomes looser and looser.

Think of the bolt as a spring. When it is tightened down it is stretched and pinches all the components together. If one of the components moves or compresses the height of the pinched components changes which also changes the bolt's stretch and the amount of pinch force it applies. As soon as you are below a threshold the bolt no longer applies sufficient pinch force to keep the joint together and all the parts spinning together. Each time the bolt can apply less and less preload exacerbating the problem and eventually it backs out.

The hub capture solution is dubious, the only thing it does is link the rotation of the bolt to the crank hub.

However the crank hub is still only fixed to the crank by the bolt threads and bolt preload. The timing gear and oil gear are sandwiched in there and still free to spin with respect to the bolt, hub, and crank. If the gears spin they will remove the preload and allow the whole of the hub and bolt to back out. The crank hub capture does not increase the preload / clamping force on the oil and timing gears!

The only thing the crank hub capture does is not allow the hub to spin with respect to the bolt. The only thing driven by the hub are the accessories (alternator, AC comp, etc). So if the accessory load is what causes the spun crank hub then the bolt capture is a possible solution, but this seems unlikely.

I think the reason no (reported) captured cars have failed is that 1) these cars are put back together with a lot of care and hence will fall into spec and not be outliers and 2) the failure numbers are relatively small anyways and the number of captured cars even smaller (and those on forums willing to share even less), so it is likely we would not hear about a failed one.

The only solution is to key a one piece hub / gear combo to the crank as Gintani does. Considering the cost of this solution and the fact most spun hubs do not cause much damage I personally will take the gamble and deal with it when it spins.

https://www.realoem.com/bmw/enUS/sho...diagId=11_5597
https://www.realoem.com/bmw/enUS/sho...diagId=11_5626

PS this is not meant as an attack on you merely info I am spreading

EDIT: Some further food for thought, my previous car a MK3 Focus RS had a similar crank hub design.

1) I money shifted it once. Was going for fourth coming out of a chicane at Zolder and got 2nd. Saw over 8k rpm (6.5k redline) on the tacho, car went into limp home mode till I restarted it several times --> no spun crank hub!
2) When carrying out the head gasket recall (common issue, about a year after the money shift) I got the car back with a spun crank hub (dealer swore they timed it right)! This issue is so rare on the Focus RS I no of no other cases of it happening. It was due to the poor reassembly on Ford's side and the fact they reused the crush washer holding it all together (equivalent to part 6 in the 1st link):
Quote:
Originally Posted by Megator View Post
Quote:
Originally Posted by armiii View Post
can you simply explain this to me?
Not without being face to face (or me drawing a pretty picture). However maybe try a little experiment. Take a bolt (preferably of a bigish diameter) and stack a bunch of flat washers on it, then tighten them all using a nut (barely tight, just enough so the washers do not move). Now spin/move the washers without spinnig the nut (this might be hard to do but the more washers you have the easier it should be to do the middle ones), eventually you should be able to get the nut to come off without needing tools.

Essentially this is what is happening with the crank hub.

Quote:
Originally Posted by F87source View Post
TBH the vtt spline lock solution sounds promising too, plus you don't have to pull the motor apart to the same extent for drilling the crank.
Spline lock has been proven not to work. Great idea but the crank is forged and hardened you are never going to "bite" into the material by screwing something on.

Aside from that it seems their machinist might not be of the highest quality, see here:

https://www.litchfieldmotors.com/blo...ank-hub-issue/
Thanks for these explanations.
Appreciate 0
      10-16-2019, 12:42 PM   #41
m20e3087
Lieutenant
m20e3087's Avatar
United_States
275
Rep
573
Posts

Drives: 19 M2C
Join Date: Mar 2012
Location: FL

iTrader: (0)

Garage List
2019 BMW M2C  [0.00]
Quote:
Originally Posted by ChrisK View Post
Quote:
Originally Posted by armiii View Post
Quote:
Originally Posted by cntzl View Post
Downshift overrev, aka money shift which can happen to any manual car due to user error whether it's stock or tuned.
That's hard to watch.
For real. Hard to watch.
Appreciate 0
      10-16-2019, 12:56 PM   #42
F87source
Captain
F87source's Avatar
Canada
225
Rep
717
Posts

Drives: 2017 Bmw M2 6mt
Join Date: Aug 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by Megator View Post
Not without being face to face (or me drawing a pretty picture). However maybe try a little experiment. Take a bolt (preferably of a bigish diameter) and stack a bunch of flat washers on it, then tighten them all using a nut (barely tight, just enough so the washers do not move). Now spin/move the washers without spinnig the nut (this might be hard to do but the more washers you have the easier it should be to do the middle ones), eventually you should be able to get the nut to come off without needing tools.

Essentially this is what is happening with the crank hub.



Spline lock has been proven not to work. Great idea but the crank is forged and hardened you are never going to "bite" into the material by screwing something on.

Aside from that it seems their machinist might not be of the highest quality, see here:

https://www.litchfieldmotors.com/blo...ank-hub-issue/
I can't trust a competitors source since it could just be a marketing tactic, but VTT said they tested it on an s55 crank which was also forged and it was able to sink in without an issue. They have also have claimed to snap cranks because it was able to bit tight enough.

In regards to machinist issues, again I've never heard of that from an unbiased third party.
__________________
Follow me on Instagram @f87source
Appreciate 0
      10-16-2019, 01:29 PM   #43
Megator
Second Lieutenant
71
Rep
202
Posts

Drives: M2 Competition
Join Date: Mar 2019
Location: NL

iTrader: (0)

Quote:
Originally Posted by F87source View Post
I can't trust a competitors source since it could just be a marketing tactic, but VTT said they tested it on an s55 crank which was also forged and it was able to sink in without an issue. They have also have claimed to snap cranks because it was able to bit tight enough.

In regards to machinist issues, again I've never heard of that from an unbiased third party.
You are indeed correct, and I dont have the objective facts regarding any solution. My views are merely informed as mecheng with some experience in this field.

I do seem to remember that VTT did not provide any proof as to their success. ie I would expect them to show a pic of a "grabbed" crank that shows the scarring caused by the splines.

I have heard it is not a viable solution from various sources though.

EDIT: BTW you might be being a bit duplicitous, on the one hand you do not trust suppliers yet trust what VTT claim?
Appreciate 0
      10-16-2019, 02:28 PM   #44
F87source
Captain
F87source's Avatar
Canada
225
Rep
717
Posts

Drives: 2017 Bmw M2 6mt
Join Date: Aug 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by Megator View Post
You are indeed correct, and I dont have the objective facts regarding any solution. My views are merely informed as mecheng with some experience in this field.

I do seem to remember that VTT did not provide any proof as to their success. ie I would expect them to show a pic of a "grabbed" crank that shows the scarring caused by the splines.

I have heard it is not a viable solution from various sources though.

EDIT: BTW you might be being a bit duplicitous, on the one hand you do not trust suppliers yet trust what VTT claim?
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.
__________________
Follow me on Instagram @f87source
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 06:28 PM.




m2
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST