Spun Crank Hub 6MT

[JohnDaviz]

Yes but not the motor is being sold off after the head allegedly lifted? Seems a little odd that a full 11mm headstud converted block is lifting the head unless your using an autozone head gasket

Elring is fine. They make good products (at least here in germany)

About the head lift. There was a video and the gasket was allegedly damaged before or during installation. So he said it was not an actual head lift. Went Athena Cutring after that and car pulled again without issues. Sold after the fix.

 

[SLOWESTN54]

Elring is fine. They make good products (at least here in germany)

About the head lift. There was a video and the gasket was allegedly damaged before or during installation. So he said it was not an actual head lift. Went Athena Cutring after that and car pulled again without issues. Sold after the fix.

We all watch the same stuff aye

 

[SlowE93]

We all watch the same stuff aye

Nope

 

[RuskiRacer]

Elring is fine. They make good products (at least here in germany)

About the head lift. There was a video and the gasket was allegedly damaged before or during installation. So he said it was not an actual head lift. Went Athena Cutring after that and car pulled again without issues. Sold after the fix.

Ahhh interesting. My plan is to use the elring gasket i have and then when my built head is ready put that on with a cut ring gasket

 

[DirtKurt]

So I have my motor out right now for my dct swap+turbos and want to do the crank hub. Im waiting to hear back from vac about the prebuy they have going. Didn't know about the bmw update untill reading through this thread. Anyone have the part numbers for the updated bmw hub? Thoughts on what direction to go

 

[RuskiRacer]

So I have my motor out right now for my dct swap+turbos and want to do the crank hub. Im waiting to hear back from vac about the prebuy they have going. Didn't know about the bmw update untill reading through this thread. Anyone have the part numbers for the updated bmw hub? Thoughts on what direction to go

If you don't wanna wait on the overpriced vac hub I will get you an insanecrankhub.com 2 pin 1 peice hub. Whenever you need

 

[SLOWESTN54]

If you don't wanna wait on the overpriced vac hub I will get you an insanecrankhub.com 2 pin 1 peice hub. Whenever you need

Ruski is definitely the crank hub plug

 

[DirtKurt]

If you don't wanna wait on the overpriced vac hub I will get you an insanecrankhub.com 2 pin 1 peice hub. Whenever you need

I will likely take you up on that!

 

[DirtKurt]

Thanks for getting me the insane hub @RuskiRacer drilling was a breeze waiting on new oil chain guide assembly and she is ready to go back together.

 

[RuskiRacer]

Thanks for getting me the insane hub @RuskiRacer drilling was a breeze waiting on new oil chain guide assembly and she is ready to go back together.

Looks good! Glad I could help.

 

[wheela]

I think i've figured out an explanation for what causes the crankhub to spin that actually explains all the different scenarios where this issue has been reported (stock power, high power, and a condition I just learned about - lugging the engine in low rpm without shifting)

I was reading a thread on f80post and a couple people reported spinning there hib just cruising in 7th gear, and hitting the gas - no shifting, just hitting the gas and bam, spun hub.

This really got me thinking, because until then everything I understood to cause the hub to spin pointed to quick engine decelaeration as the culprit (crank slows abruptly, but the rotational inertia of everything driven by the hub keeps spinning, breaking the hub loose). How the heck could the hub have spun when the engine barely changed rpm

So the theory I've come up with is this - the crankshaft is storing energy like a torsion spring under torque, and when the torsion lets go it breaks the hub loose. Here are my thoughts...

If you're lugging the engine hard in low rpm, each power stoke of a piston is winding up the crankshaft like a torsion spring against the transmission. When the exhaust valve of the driving piston opens, all that torque is momentarily released, and the crankshaft can violently unwind the degree or two (guessing on magnitude, maybe more or less depending on torque?) of twist that built up during the power stroke. This would be especially challenging when piston 1 is providing the torque to the shaft, as the whole length of crankshaft is winding up. Normally the harmonic balancer should be able to minimize/mitigate the spring-back of the crankshaft when the exhaust valves open. But lugging at low rpm, there isn't enough momentum in the balancer for it to normalize crank shaft speed effectively.

So the issue would be worse at low rpm due the reduced effectivess of the harmonic balancer at low rpm. This explains why hubs can spin on stock power; imagine all the twist in the crankshaft that is repeatedly slamming the hub as it releases with each exhaust valve opening event...

It also explains why high power builds encounter it despite not having any more rotating mass being driven by the hub: more torque = more crankshaft twist during power stroke = more violent springback during the exhaust valve opening event.

Thoughts?

 

[Cruizinmax]

If you can visualize the rotation of the crank, it spins clockwise, what would actually loosen the bolt would be if the balancer were going slower than the crankshaft. So I believe what causes the bolt to loosen is the crank speed zinging up like on a downshift.

My opinion is these behaviors are loosening the bolt over time. Just because the car dies or throws a codes doesn't necessarily mean that is the instant the bolt came loose. It just means it became loose enough to overcome the friction discs at that moment.

 

[martymil]

The crank hub is not the only issue, once you lock it the intake vanos hub becomes the problem as it works on the same principal.

I had a customer that had one slip at around 900hp at 28 psi., whilst not common it can happen.

 

[SLOWESTN54]

The crank hub is not the only issue, once you lock it the intake vanos hub becomes the problem as it works on the same principal.

I had a customer that had one slip at around 900hp at 28 psi., whilst not common it can happen.

Never seen or thought of that one. I guess they aren’t keyed. Maybe use a higher grade bolt with more torque

 

[wheela]

The crank hub is not the only issue, once you lock it the intake vanos hub becomes the problem as it works on the same principal.

I had a customer that had one slip at around 900hp at 28 psi., whilst not common it can happen.

Did they say what the conditions were at the moment it let go?

 

[martymil]

On full throttle threw a vanos code.

 

[martymil]

Will be talking with our engine builder and see if we can come up with a solution.

The problem with single turbos is the huge power and torque dump and the upgraded springs in the head don't help either as it takes a lot more energy to spin the cams.

I'll have a chat and try come up with a solution.

Maybe the vanos didn't slip but fail internally, mind you it's less than 10k old.

More on this after we pull the rocker cover off.

 

[BeamerBullie]

The crank hub is not the only issue, once you lock it the intake vanos hub becomes the problem as it works on the same principal.

I had a customer that had one slip at around 900hp at 28 psi., whilst not common it can happen.

can you explain this im getting 2a98/3100 intake reference on a ST manual. First I thought it was my cam ledge as I had the same code but for exhaust side, changed with brand new even though it looked fine normal wear (when I changed exhaust side I put the teflon seals onto the intake side). Car ran fine for a week code popped back up I'm like no way 2a98 and 3100. Checked timing exhaust side was on point intake was off by a degree or 2 as timing tool wouldn't slide on. Adjusted timing and changed tensioner. Did a few pulls car was good. Next day do light pulls 2nd to 3rd code reappeared. I notice intake vanos "actual" and "required" are slightly off and "actual" jumps around. I can clear the codes and on idle it won't reappear but once start to drive it pops up. Contemplating pulling motor and doing chain guides hub etc or swapping junk yard motor and building this one.

To my understanding and from what I've seen when it slips you get exhaust and intake vanos codes. Im only getting intake and I figured maybe the vanos sprocket may be fault have another one to test out but would like opinions as Im tired of taking this thing apart every other week.

BTW garret g35-1050 on about 19-22psi depending on weather.
Motor is stock internally however I know it ate a belt as when I bought it it had the belt in the pickup tube but all that was cleaned out prior to refreshing seals on the motor. Also cam trays and cams are from another motor I had laying around can't recall if I used the same sprockets from the motor that ate the belt though.

 

[martymil]

can you explain this im getting 2a98/3100 intake reference on a ST manual. First I thought it was my cam ledge as I had the same code but for exhaust side, changed with brand new even though it looked fine normal wear (when I changed exhaust side I put the teflon seals onto the intake side). Car ran fine for a week code popped back up I'm like no way 2a98 and 3100. Checked timing exhaust side was on point intake was off by a degree or 2 as timing tool wouldn't slide on. Adjusted timing and changed tensioner. Did a few pulls car was good. Next day do light pulls 2nd to 3rd code reappeared. I notice intake vanos "actual" and "required" are slightly off and "actual" jumps around. I can clear the codes and on idle it won't reappear but once start to drive it pops up. Contemplating pulling motor and doing chain guides hub etc or swapping junk yard motor and building this one.

To my understanding and from what I've seen when it slips you get exhaust and intake vanos codes. Im only getting intake and I figured maybe the vanos sprocket may be fault have another one to test out but would like opinions as Im tired of taking this thing apart every other week.

BTW garret g35-1050 on about 19-22psi depending on weather.
Motor is stock internally however I know it ate a belt as when I bought it it had the belt in the pickup tube but all that was cleaned out prior to refreshing seals on the motor. Also cam trays and cams are from another motor I had laying around can't recall if I used the same sprockets from the motor that ate the belt though.

Ok finally got around to it and timing is out, something slipped which looks like the crank hub has moved as both the intake and exhaust vanos hubs out 10 deg on my mates motor.

It was only throwing intake vanos code.

The timing slipped during a WOT pull at 28psi.

This motor is running a custom billet crank and one piece hub.

 

[BeamerBullie]

Ok finally got around to it and timing is out, something slipped which looks like the crank hub has moved as both the intake and exhaust vanos hubs out 10 deg on my mates motor.

It was only throwing intake vanos code.

The timing slipped during a WOT pull at 28psi.

This motor is running a custom billet crank and one piece hub.

thanks you mind sharing which hub? im contemplating which one to go with vtt insane or just oem revision