CBC is TRASH! Need recommendations

[MagicF8x]

Originally Posted by b_w.

How long was it installed for?

Just a little over a year

[wheela]

When you say it practically failed, what do you mean? Did the pins shear? Also, McMaster Carr is a distributor, they don't manufacture anything.

[FrankMstein]

Originally Posted by MagicF8x

I had all but 2 snap off, they were able to extract the bolts and swap with new oem
Bolts

These were over-tightened. You can see they were necked down (look at the bottom one) and the threads were nearly rounded off. I would not be surprised if they were stressed, cracked, and while removed were broken due to the destroyed threads. I sure hope the item's threads these screws were put in wasn't destroyed too. Can you send a pic of the drive with the numerals towards the camera? Are they YFS?

[FrankMstein]

Originally Posted by wheela

When you say it practically failed, what do you mean? Did the pins shear? Also, McMaster Carr is a distributor, they don't manufacture anything.

I'd like to know as well. Glad you said MMC doesn't make anything, as I was going too.

[x_]

Originally Posted by MagicF8x

I had all but 2 snap off, they were able to extract the bolts and swap with new oem
Bolts

Correct me if I'm wrong, but does that say A2-70 on the heads? If it does, it's a lot weaker than what 12.9 is supposed to be.

Also thanks to the guy that posted how to check the CBC. I'll be buying an inspection camera off the net to have a look.

[hC1001]

Originally Posted by FrankMstein

These were over-tightened. You can see they were necked down (look at the bottom one) and the threads were nearly rounded off. I would not be surprised if they were stressed, cracked, and while removed were broken due to the destroyed threads. I sure hope the item's threads these screws were put in wasn't destroyed too. Can you send a pic of the drive with the numerals towards the camera? Are they YFS?

I agree. You can look at how deep the bolts digged into the aluminum of the CBC. The only hole that looks decent is the one at 7 o clock. I bet that is the hole of the only good non-deformed bolt they were able to unscrew. The second full length bolt they unscrewed is stretched in the middle and was over-tightened during install.

25ft/lb shouldnt dig into the aluminum that much but i could be wrong... We also cant confirm what markings are on the bolt heads to get grade...

[Beemerm3]

Originally Posted by ra2289

Care to elaborate on the 4 pin issue? Who made it, how long it is was in the car, what the failure looked like and/or any other information you can provide. Very interested as I have not heard of any pinned hub failing.

i dont think hes talking about the 4 pin but actually 4 bolts snapping off.

[Beemerm3]

it seem like the crank hub is slipping inside and breaking loose the middle bolt then breaking the small bolts all at the same time. just saving your engine at least. im going with insane one piece when i have the money to install it with vtt.

[e46IX]

These CBC's that are failing, how many of them are paired up with the Vargas splined crank hub? Are they installed with OEM crank hub or another company's pinned version?

[F80RN]

I’ll leave this for everyone else to interpret, as I don’t know how to. But here’s some things I noticed (I asked to keep my old hub and CBC cause I want to incorporate it into my sim racing rig &#128514

1. When the bolts aren’t tightened down, there’s some play with the actual CBC back and forth

2. My hub didn’t have anything that stood out to me (apart from being outside of the engine lol)

3. There’s some markings on the CBC that show where it was torqued down. Does it mean it would have play? I’m not sure.

4. The CBC doesn’t fully sit on top of the hub. There’s a small gap. Is this by design or is it a possible cause of them going bad?

*EDIT*

I have a short clip but how do I attach that?

[wheela]

Originally Posted by F80RN

I’ll leave this for everyone else to interpret, as I don’t know how to. But here’s some things I noticed (I asked to keep my old hub and CBC cause I want to incorporate it into my sim racing rig &#128514

1. When the bolts aren’t tightened down, there’s some play with the actual CBC back and forth

2. My hub didn’t have anything that stood out to me (apart from being outside of the engine lol)

3. There’s some markings on the CBC that show where it was torqued down. Does it mean it would have play? I’m not sure.

4. The CBC doesn’t fully sit on top of the hub. There’s a small gap. Is this by design or is it a possible cause of them going bad?

*EDIT*

I have a short clip but how do I attach that?

Hopefully the thickness of the harmonic balancer flange is thicker than that gap... Assuming that picture was taken with the screws fully bottomed out in their holes?

[F80RN]

Originally Posted by wheela

Hopefully the thickness of the harmonic balancer flange is thicker than that gap... Assuming that picture was taken with the screws fully bottomed out in their holes?

Yes the screws are fully bottomed out.

[Fat Goose]

Originally Posted by wheela

Hopefully the thickness of the harmonic balancer flange is thicker than that gap... Assuming that picture was taken with the screws fully bottomed out in their holes?

This, Harmonic balancer

[fandango202]

Checked mine today on my 2019 M2C. Had this installed by my local Indy early February and have put 2,2xx miles on the car since then (most of which has been spirited driving). That same week I tuned the car to stage 2 with a ‘custom’ map from Jordan tuned via BM3. So far the CBC and bolts look fine. Will keep an eye on it. Just sharing another data point.

[f87_ben]

Another datapoint, 2018 M2.
Got it with the combo deal with the crank seal guard in anticipation of a big turbo.
Purchased in January and installed February, driven installed for 20,000 miles on BM3 Stg2+ E85.

Installed with red Loctite to "good n tight" in a star pattern then went back around with a torque wrench set to 30ftlb.

[kxsb]

Same as well. Mine was installed 6 months ago with Blue Loctite. None have broken yet, but good to know this can happen.

[Groganrocket]

Originally Posted by kxsb

Same as well. Mine was installed 6 months ago with Blue Loctite. None have broken yet, but good to know this can happen.

I’m wondering the ones you guys have don’t have any rust on them, mine car hasn’t been in the rain and it showing rust like a couple others here, so I’m wondering if your bolts are different.
Are your bolts black or sliver looking not sure if it’s the pic or not, but they last 2 pics the bolt look silver.

[x_]

People that have their CBC still intact, are you guys only on CBC or with a different/pinned hub as well?

I've just gone through the thread again and it seems like all of the failed CBC's had changed their crank hub as well.

I finally got my inspection camera but I have no idea how some of you have really clear photos. It took me about 40 mins to take about 20 photos and get close ups of each bolts and they look like blurry piles of shit, I'll post the 3 clearest ones.

Good news is all of mine look ok so far, bad news is that EEP seems to have switched over to YFS bolts as well as that's what I have on mine. The CBC was installed mid December so it's been about 8 and a bit months of the car, I don't have a modified crank hub.

[fandango202]

Originally Posted by x_

People that have their CBC still intact, are you guys only on CBC or with a different/pinned hub as well?

I've just gone through the thread again and it seems like all of the failed CBC's had changed their crank hub as well.

I finally got my inspection camera but I have no idea how some of you have really clear photos. It took me about 40 mins to take about 20 photos and get close ups of each bolts and they look like blurry piles of shit, I'll post the 3 clearest ones.

Good news is all of mine look ok so far, bad news is that EEP seems to have switched over to YFS bolts as well as that's what I have on mine. The CBC was installed mid December so it's been about 8 and a bit months of the car, I don't have a modified crank hub.

I’m on stock crank hub with only the CBC added on - bolts all intact as shown a few posts up. I didn’t notice the failed CBC posts had modded hubs…

I used an articulating inspection camera which makes it way easier to get pictures. https://a.co/d/6THx6zp

[x_]

Originally Posted by fandango202

I’m on stock crank hub with only the CBC added on - bolts all intact as shown a few posts up. I didn’t notice the failed CBC posts had modded hubs…

https://a.co/d/6THx6zp

Well, OP never came back to the thread so have no idea about him but Todd20 and S55_M3 had aftermarket hubs.

Originally Posted by S55_M3

I wonder if the issue is only in conjunction with a upgraded crank hub. I have the 2 pin solid design and I am seeing signs of movement with the cbc

Originally Posted by todd20

These were installed by a reputable shop and all 8 were installed I checked when I got it. From my understanding the bolts got loose and came out over the course of 2-4 months. Once enough bolts came out of one side, the harmonic balancer started to get wobbly and started to grind down on the other bolts. This is why only two are stuck in the hub instead of all 6. Also this is a Lang racing 4 pin hub not a stock one

Not sure about MagicF8X as he didn't come back to the thread as well, but he posted this

Originally Posted by MagicF8x

CBC doesn’t really do anything , their spline lock is definitely the best crankhub solution , my 4 pin practically failed.

These are definitely stress failures,
When my bolts snapped off they were replaced with oem ones.

You can look up those bolts they are manufactured by a company called McCmaster carr out of Illinois and I don’t belive they have the strength that oem bolts do.

It seems like the bolts that were installed were A2-70 from what I can see in the picture, which has a shear strength of 700N/mm² vs 12.9 grade which is supposed to have 1200N/mm².

[FrankMstein]

Originally Posted by x_

Well, OP never came back to the thread so have no idea about him but Todd20 and S55_M3 had aftermarket hubs.






Not sure about MagicF8X as he didn't come back to the thread as well, but he posted this





It seems like the bolts that were installed were A2-70 from what I can see in the picture, which has a shear strength of 700N/mm² vs 12.9 grade which is supposed to have 1200N/mm².

They do look SS which is why I asked for another pic of the drive. DO NOT use stainless steel for this application.

[Wanted_M]

No issues so far, sorry for the crappy pic.