Reported SCH due to engine design flaw while using CBC?

[MisterF80M3]

Originally Posted by jason.404

Can you dm me the service cost for the cbc? Looking to get mine done soon.

$400-500. Owner owns a S55 with a single turbo. Extremely knowledgeable on the S55 platform.

Originally Posted by deeldoo

Add me to the list of CBC only.

2016 M4 DCT on just a cs tune, i can't justify spending 4k on a stock power level car.

2018 F80 DCT Stage 2 E30 tune FBO with CBC only. Planning to go full e85 in the near future.

Originally Posted by Walmart Parking Lot

VTT even said CBC is not a full solution to prevent the crank hub from spinning. Lmao

Just get a full crank hub solution with or without CBC and call it a day.

Did you read the last few pages? Contains a lot of information of why CBC alone is sufficient.

[MJ6]

Bringing this one back as I was digging through the thread and questioned the efficacy of using the situation referenced in the post below as proof of a spun a hub with CBC installed
https://f80.bimmerpost.com/forums/sh....php?t=1679594

This thread was brought up as definitive proof that a CBC isn't enough to prevent a SCH as the OP experienced a spun hub after the installation of the V1 Spline Lock and CBC. Looking through the thread it would appear that the V1 didn't bite into the hub as intended (which is why V2 was introduced in the first place), and the CBC by itself couldn't prevent the spin.

The problem with this logic though is that when installing crank hub fixes such as the spline lock or pinned solutions, they're meant to replace the stock friction washers correct? Therefore when the new hub is installed (and correct me if I'm wrong) the friction washers are omitted from the installation process entirely. If this is the case and the splines fail to bite or the pins are installed incorrectly, what is there left to provide rotational resistance on the hub?

In the referenced thread, when the splines failed to bite into the hub, the only thing clamping everything together was the crank bolt fitted with the CBC; but without a mating surface/friction coefficient on the hub to provide resistance, regardless the of clamping force provided by the bolt, it would only be a matter of time before it gave.

Essentially, even though the hub spun I don't feel that it can be held as definitive proof of a CBC failing.

[Chris@VargasTurboTech]

Not quite, good thought but missing a bit of info -our hub uses a stock oil sprocket and has friction discs spot welded to it.

CBC alone does a good job reducing the risk, but to retire the risk completely a spline lock and CBC together are the key to victory.

Chris

[jpy1980]

Originally Posted by Chris@VargasTurboTech

Not quite, good thought but missing a bit of info -our hub uses a stock oil sprocket and has friction discs spot welded to it.

CBC alone does a good job reducing the risk, but to retire the risk completely a spline lock and CBC together are the key to victory.

Chris

Hey Chris, in the case of Bracer's V1 hub slipping, were the friction discs also spot welded on that one too? or just the V1?

[Chris@VargasTurboTech]

All of them still have friction discs. It wouldn't make sense to take away hub torque capacity with one aspect and add it another place.

[6SPD GOD]

Originally Posted by Chris@VargasTurboTech

All of them still have friction discs. It wouldn't make sense to take away hub torque capacity with one aspect and add it another place.

makes sense

[Gotulukn]

Originally Posted by TopJimmy

The CBC only locks the crank bolt in place. If the crank bolt had slipped a tiny bit before you add a CBC then the bolt is still not tight enough even though it's now locked in place, and the friction washer could slip. The "German Solution" is to install a new crank bolt with an extra quarter turn (360deg instead of 270deg) and then install the CBC. I've asked a very reputable shop (private) to do the German Solution and they said a re-time and CBC install will cost almost as much labor time as a real hub fix. I scheduled the hub fix, and my shop will install my CBC at no extra cost since it can easily be added during reassembly.
.

If anyone can chime in, 2015 f83 m4 with 53k miles with a Jb1. Can I just ask my tuner to give the stock crank hub bolt an extra quarter turn, then install the VTT capture plate? OR is it a must that the crank bolt has to be replaced, then timing has to be re-adjusted, then tighten 100nm +360 degrees?

[Mikez306]

I've been following this thread for awhile, and although I initially planed on doing the hub "upgrade", I've since changed my mind. Besides the fact that as this thread indicates there is nothing but antidotal evidence (some guy, some where who knows a guy) that a hub has ever slipped with a CBC installed. Of course there was the one case where the guy hit 9500RPM, which clearly needs to be taken into context. There have been so many well documented cases of the stock hub slipping, you'd have to expect the same would exist if a hub has ever slipped with a CBC.

This is not to throw shade of anyone who's done the upgrade, or those companies have invested their time and money creating these parts.

There's just no consensus. The only consensus. I've been able to find is outside of money shifts, is there have been no incidences of hub slip with a CBC.
Please check the link below from Litchfield, I found it very informative. They seem to be all but certain that a CBC is all that is needed and also mention what they feel are the design flaws in the both the keyed/splined fixes. In fact they only recommend their full one piece hub solution for vehicles that have already had the hub slip.

So at this time, I will stick with my VTT CBC and see what happens.






https://www.litchfieldmotors.com/blo...ank-hub-issue/

[Eric SS]

Originally Posted by Mikez306

I've been following this thread for awhile, and although I initially planed on doing the hub "upgrade", I've since changed my mind. Besides the fact that as this thread indicates there is nothing but antidotal evidence (some guy, some where who knows a guy) that a hub has ever slipped with a CBC installed. Of course there was the one case where the guy hit 9500RPM, which clearly needs to be taken into context. There have been so many well documented cases of the stock hub slipping, you'd have to expect the same would exist if a hub has ever slipped with a CBC.

This is not to throw shade of anyone who's done the upgrade, or those companies have invested their time and money creating these parts.

There's just no consensus. The only consensus. I've been able to find is outside of money shifts, is there have been no incidences of hub slip with a CBC.
Please check the link below from Litchfield, I found it very informative. They seem to be all but certain that a CBC is all that is needed and also mention what they feel are the design flaws in the both the keyed/splined fixes. In fact they only recommend their full one piece hub solution for vehicles that have already had the hub slip.

So at this time, I will stick with my VTT CBC and see what happens.






https://www.litchfieldmotors.com/blo...ank-hub-issue/

To add to this, I feel like the people adding the CBC are the ones that have boosted the HP of their car. If they truly didn't work I would think there would be higher incidents of SCH with a capture only than no capture because of people's expectations (and supposed false sense of security) that it works so they push the limits. Instead, there doesn't seem to be any.

[DrunkStig]

Originally Posted by Eric SS

To add to this, I feel like the people adding the CBC are the ones that have boosted the HP of their car. If they truly didn't work I would think there would be higher incidents of SCH with a capture only than no capture because of people's expectations (and supposed false sense of security) that it works so they push the limits. Instead, there doesn't seem to be any.

Originally Posted by Eric SS

To add to this, I feel like the people adding the CBC are the ones that have boosted the HP of their car. If they truly didn't work I would think there would be higher incidents of SCH with a capture only than no capture because of people's expectations (and supposed false sense of security) that it works so they push the limits. Instead, there doesn't seem to be any.

I totally agree with this. I did the CBC and that's all I plan to do.

My current setup it 57k on a 2015 with BM3 stage 1

[Mikez306]

Originally Posted by DrunkStig

I totally agree with this. I did the CBC and that's all I plan to do.

My current setup it 57k on a 2015 with BM3 stage 1

It also appears that Litchfield can also confirm this. I emailed them and asked if their cbc was available for purchase, it sadly is not however they did confirm they've never spun a crank hub with the capture in place.

Hard to justify a $2-$4k repair with this type of evidence.

[tom @ eas]

Originally Posted by Mikez306

It also appears that Litchfield can also confirm this. I emailed them and asked if their cbc was available for purchase, it sadly is not however they did confirm they've never spun a crank hub with the capture in place.

Hard to justify a $2-$4k repair with this type of evidence.

This is an opinion, not evidence.

One's specific comfort level on cost for peace of mind (whether its CBC only or Crank Hub + CBC) is purely up to them.

[bsmf8x]

Originally Posted by Mikez306

I've been following this thread for awhile, and although I initially planed on doing the hub "upgrade", I've since changed my mind. Besides the fact that as this thread indicates there is nothing but antidotal evidence (some guy, some where who knows a guy) that a hub has ever slipped with a CBC installed. Of course there was the one case where the guy hit 9500RPM, which clearly needs to be taken into context. There have been so many well documented cases of the stock hub slipping, you'd have to expect the same would exist if a hub has ever slipped with a CBC.

This is not to throw shade of anyone who's done the upgrade, or those companies have invested their time and money creating these parts.

There's just no consensus. The only consensus. I've been able to find is outside of money shifts, is there have been no incidences of hub slip with a CBC.
Please check the link below from Litchfield, I found it very informative. They seem to be all but certain that a CBC is all that is needed and also mention what they feel are the design flaws in the both the keyed/splined fixes. In fact they only recommend their full one piece hub solution for vehicles that have already had the hub slip.

So at this time, I will stick with my VTT CBC and see what happens.






https://www.litchfieldmotors.com/blo...ank-hub-issue/

This is a great point. It's interesting to think that there's hundreds or thousands of cars that have done the upgrade, aka millions of $$$ to shops for the full 3k when the CBC would probably suffice on anyone under 550 whp

[Mikez306]

Originally Posted by tom @ eas

This is an opinion, not evidence.

One's specific comfort level on cost for peace of mind (whether its CBC only or Crank Hub + CBC) is purely up to them.

You feel that Litchfield is offering an opinion on if their has been a crank hub failure with their capture installed? With all due respect that's a bit far fetched. Who would know if not them? It would also be in their best interest to state the cbc alone was not sufficient, since they also sell the full solution.

I'm not saying the full fix is not the solution, I am simply stating that there is an absence of evidence to indicate the cbc alone is not sufficient.

[tom @ eas]

Originally Posted by Mikez306

You feel that Litchfield is offering an opinion on if their has been a crank hub failure with their capture installed? With all due respect that's a bit far fetched. Who would know if not them? It would also be in their best interest to state the cbc alone was not sufficient, since they also sell the full solution.

I'm not saying the full fix is not the solution, I am simply stating that there is an absence of evidence to indicate the cbc alone is not sufficient.

I'm saying all third parties outside BMWs engineering team are considered opinions, including mine.

Full fix is the solution for some, CBC only for others. And that's perfectly fine - there's no fault for owners having different opinions.

[Wanted_M]

Originally Posted by tom @ eas

I'm saying all third parties outside BMWs engineering team are considered opinions, including mine.
Full fix is the solution for some, CBC only for others. And that's perfectly fine - there's no fault for owners having different opinions.

Tom, IMHO your opinion matters as EAS and others have built a good reputation all around including Litchfield. All shops make recommendations to customers which the majority tend to follow based on your shop experience and market trends. Whether is suspension, wheels, exhaust or overall parts advise. The crank hub vs. CBC debate will go on till the end of time, what came first, the chicken or the egg lol

Can you let us know which of the combos has EAS installed the most CBC, hub or both?
Thanks.

[tom @ eas]

Originally Posted by Wanted_M

Tom, IMHO your opinion matters as EAS and others have built a good reputation all around including Litchfield. All shops make recommendations to customers which the majority tend to follow based on your shop experience and market trends. Whether is suspension, wheels, exhaust or overall parts advise. The crank hub vs. CBC debate will go on till the end of time, what came first, the chicken or the egg lol

Can you let us know which of the combos has EAS installed the most CBC, hub or both?
Thanks.

Most installs are both CBC + Crank Hub. We've only had one request for CBC only.

[Wanted_M]

Since we can all agree that once the bolt starts to become loose, you'll slowly slip away at a predetermined rate while you're ECU/cam adjuster/phaser might compensate for the chain slack before it goes WHAM hub slips!!

Hear me out here, I came from an B8.5 S4 and those cars suffer from timing chain tensioner issues which can cause timing chain slip and damage to valves if left untreated, one way I use to keep track of that was by using VCDS to monitor cam adjustment/phase adjustment on intake for both banks, if the threshold shifts from specified vs actual (to negative) then you knew something was happening and might be able to predict the slip before the tensioner took you out. Measured while the car is warm and running/idle not hot.

Just a thought as I'm too new on this platform and learning. Is that's an option that can be logged and analyzed? Has anyone tried this?

Example log from VCDS:

[Mikez306]

Originally Posted by Wanted_M

Since we can all agree that once the bolt starts to become loose, you'll slowly slip away at a predetermined rate while you're ECU/cam adjuster/phaser might compensate for the chain slack before it goes WHAM hub slips!!

Hear me out here, I came from an B8.5 S4 and those cars suffer from timing chain tensioner issues which can cause timing chain slip and damage to valves if left untreated, one way I use to keep track of that was by using VCDS to monitor cam adjustment/phase adjustment on intake for both banks, if the threshold shifts from specified vs actual (to negative) then you knew something was happening and might be able to predict the slip before the tensioner took you out. Measured while the car is warm and running/idle not hot.

Just a thought as I'm too new on this platform and learning. Is that's an option that can be logged and analyzed? Has anyone tried this?

Example log from VCDS:

Good point. In the Litchfield article posted above, they mention that they check to see if slippage has occurred prior to installing the cbc. I'm not sure how they would check, my best guess would be using ISTA?

[jpy1980]

Originally Posted by tom @ eas

Most installs are both CBC + Crank Hub. We've only had one request for CBC only.

Yayy! That must’ve been me! Haha

[Chris@VargasTurboTech]

As data comes in, I always revise my position if applicable. Haven't seen a stock hub and CBC spin under 600 whp in the past year. I know some of you guys are going to say that I haven't seen a stock hub/cbc spin regardless, which isn't true and is a different story that I really am not super interested in getting into again (ok you talked me into it; complete solution is both). The hub and CBC retires the risk, but I haven't seen any stock hub cbc under 600 in the past year have an issue. Don't take this as authoritative just because I'm a vendor, take it as anecdotal because that's what it is -I don't see all the data all the time, but I do always have an ear to the ground to see how this plays out over time.

Stay safe!
Chris

[Mikez306]

I came across something pretty interesting today, relevant to this topic. I was watching a Kies Motorport YouTube video today and the host Brian (I think) was doing a full motor swap on a S55 M3 with a spun crank hub.

The part I found interesting is (around the 9:25s point of the video) he says while examining the blown motor, the crank hub bolt was finger tight and he was able to loosen it by hand. Would a CBC prevented the failure on this car? Maybe, maybe not but still interesting none the less.

https://www.youtube.com/watch?v=0J6S_aYwL4g