[Supr3me]

Based on chatter in the B58 FB group I understand that if you start having this sound after engine shutdown, it's an early indicator of eccentric shaft failure.
I wanted to post the video here and get some feedback from this group as the conversation tends to be more productive and technical than in the FB group.
I'm looking to see if you all can point me towards some resources about the B58 eccentric shaft and possibly answer a few questions.
One note about the video, the phone mic REALLY picked up the sound quite well. It's not that loud in person.

1. Can anyone else confirm the initial diagnosis - eccentric shaft (ES) wear? There is also an ES motor and sensor. Could issues with those components be causing the after shutdown chatter, or is it most likely the shaft itself?

2. How does the progression of the eccentric shaft wear --> failure process look? Does this sound likely mean full failure is imminent and I need to schedule replacement immediately? Or is it a longer process?

3. What are the possible outcomes of waiting for full ES failure before replacement? I understand that the ES controls VANOS activity so the car would likely be undriveable. But could the ES failure also cause more catastrophic issues?

4. I understand the teardown for eccentric shaft replacement involves removing the valve cover and some retainer springs that can be quite tricky. Sounds like there is also some position relearning needed after replacement. What other recommended work or upgrades could/should be done when I have it torn apart? PCV replacement/upgrade? Other things?

I know this is a long list of questions, any insight would be helpful. Just trying to educate myself about this part, it's function, and looking for teardown instruction resources.

Video link: https://photos.app.goo.gl/AEch4F4YpEDKcQ9X7

[weehe126]

Was the engine off for that video? On the N55 the servomotor would go out before having issues with the actual shaft. From what I've seen the reason a shaft would go bad is if it is no longer lubricated and binds. If you actually have an issue and caught it early enough you might be able to take the shaft out and clean up and lube the caps. I haven't seen much on this issue for the B58, but that sound does not match the N55 sound that actually indicates an issue. Yours almost sounds like a vacuum pump or evap pump.

[Supr3me]

Originally Posted by weehe126

Was the engine off for that video? On the N55 the servomotor would go out before having issues with the actual shaft. From what I've seen the reason a shaft would go bad is if it is no longer lubricated and binds. If you actually have an issue and caught it early enough you might be able to take the shaft out and clean up and lube the caps. I haven't seen much on this issue for the B58, but that sound does not match the N55 sound that actually indicates an issue. Yours almost sounds like a vacuum pump or evap pump.

Yes, the video was immediately after engine shutoff. Usually lasts about 90 seconds after shutoff and kind of... winds down. Gets quieter and starts to become intermittent and slower. It doesn't do it after every drive. Seems related to how "spirited" the drive was whether it shows up or not. I can't 100% tell if the sound is happening when the engine is running but I believe it's not.

[john_f30]

I have the same issue. My car is at the dealership again for the third time.

First they suspect the VVT motor is failing so they replaced the unit. Got the car back and after a day it started buzzing again.

Took it back to them. They opened the valve cover to check all components, it looks ok per the shop foreman. Updated the firmware and said it's fixed. Picked up my car and showed me that buzzing is gone. I said ok and drove home. Got home, parked my car in the garage, shut off the engine, buzzing started again! Much louder than the last time.

Hopefully third time they replace the eccentric shaft.

I saw another post from therealm3 with the same issue. His dealership replaced the eccentric shaft and the buzzing is gone.

[Supr3me]

Originally Posted by john_f30

I have the same issue. My car is at the dealership again for the third time.

First they suspect the VVT motor is failing so they replaced the unit. Got the car back and after a day it started buzzing again.

Took it back to them. They opened the valve cover to check all components, it looks ok per the shop foreman. Updated the firmware and said it's fixed. Picked up my car and showed me that buzzing is gone. I said ok and drove home. Got home, parked my car in the garage, shut off the engine, buzzing started again! Much louder than the last time.

Hopefully third time they replace the eccentric shaft.

I saw another post from therealm3 with the same issue. His dealership replaced the eccentric shaft and the buzzing is gone.

Thanks for the info. Can you give me some deets on your car? Model, mileage, mods?

[jackstrath]

Originally Posted by Supr3me

Thanks for the info. Can you give me some deets on your car? Model, mileage, mods?

Just for comparison can you post yours?

[john_f30]

Originally Posted by Supr3me

Thanks for the info. Can you give me some deets on your car? Model, mileage, mods?

2016 340i, 51k miles, Stock no mods (yet.. lol)

[Supr3me]

2016 340i xDrive 60K miles.
Many mods lol. About 600 WHP.
I pushed the car quite a bit this fall to hit some Dragy numbers I was chasing, dozens of launches. Not hundreds, tho. I know a lot of guys that have been driving theirs harder.

[john_f30]

Got an update from my service advisor. The technician determined that the eccentric shaft was causing the VVT motor to whine, buzz, and/or chatter. Did not say it was failing but since they are going to replace the complete eccentric assembly, I think it is. Parts will be coming from Germany so unfortunately I have to wait 2 weeks.

[Jnat]

Originally Posted by john_f30

Got an update from my service advisor. The technician determined that the eccentric shaft was causing the VVT motor to whine, buzz, and/or chatter. Did not say it was failing but since they are going to replace the complete eccentric assembly, I think it is. Parts will be coming from Germany so unfortunately I have to wait 2 weeks.

Sorry to hear.
Warranty or customer pay? Either way, what is the customer pay amount range if that's the situation?

[john_f30]

Originally Posted by Jnat

Sorry to hear.
Warranty or customer pay? Either way, what is the customer pay amount range if that's the situation?

Warranty covered it.

Not sure how much it's going to be if customer pays. My guess labor is going to be pretty high as it looks like a big job. Teardown involves alot of parts removal to get to the eccentric assembly including the intake camshaft.

How do I know? I watched this video. Not the same car but it's a B58

[therealm3]

Hello,

I am posting the parts list from my repair order for those trying to do this outside of a dealer repair. According to my SA, it is a pretty big job. They had my car for several days.

For reference, mine is a 2016 340i 6MT with 43k miles. No engine mods. I change the oil every 5k miles.

Hopefully this helps others in the future.

[Supr3me]

Thank you to therealm3 and john_f30 for all the info. The parts list is invaluable. I found the shaft at BMW Parts Link for $870 which is $200 cheaper than the dealership. I haven't put all the other stuff in the cart but I'm expecting them to run another ~$300 or so.
I have a buddy who's a professional mechanic and I'm negotiating with him now on whether he wants to help me with the work and what a fair price for his time is.
I'll keep you posted on what we decide!

[TheFanatic]

I wonder what causes it to wear, I'm at 119k miles and haven't had that issue thankfully

[Supr3me]

Originally Posted by TheFanatic

I wonder what causes it to wear, I'm at 119k miles and haven't had that issue thankfully

This is purely a guess on my part- someone with more classical mechanical training could tell you if I'm barking up the wrong tree. I wonder if it's related to the fact that there's no BOV and the VANOS system has to manage and release that excess pressure. And if you're running an upgraded turbo - more pressure to manage and release via the valves.

[weehe126]

Vanos and the eccentric shaft are not related. The only way the shaft can be damaged is if debris somehow get between the shaft and the cap. Think of it like a camshaft, but instead of going in circles with the crank rotation, it goes -90° to +90° depending on throttle.

[Supr3me]

So maybe I should be using the term valvetronic instead? The eccentric shaft definitely helps manage valve timing.
And the issue that's been happening is not damage. It's uneven wear, which then makes the shaft bind which causes the actuator to buzz (the initial symptom we've all had).

[weehe126]

Yes, it is a part of the valvetronic system. You can see the wear? Have you tried to turn the shaft by hand to see where it binds?

[Supr3me]

Originally Posted by weehe126

Yes, it is a part of the valvetronic system. You can see the wear? Have you tried to turn the shaft by hand to see where it binds?

No. I haven't attempted the teardown yet. The description of the wear indication is from the technical notes screenshots above and also has been documented elsewhere as I've been researching the issue. Can't remember where now.

[therealm3]

Now that I have some miles on my car after the repair, I am pleased to say the noise has not come back. And more importantly, the odd flat spots or irregularities in the power curve I would feel with medium throttle application are gone. The engine is much smoother and pulls in a more linear fashion. I am so happy BMW figured this out and did the job.

[john_f30]

therealm3 is correct about the flat spots and irregular power curve. That is what I'm experiencing right now. When I drive slow I don't feel it much but when I give it more gas like trying to pass another car or entering the freeway, you can definitely feel the power cuts off then resumes. It's like a weird turbo lag but happens in-between acceleration.

Still have 1.5 weeks to go til the parts come in. Can't wait!

[weehe126]

Originally Posted by Supr3me

No. I haven't attempted the teardown yet. The description of the wear indication is from the technical notes screenshots above and also has been documented elsewhere as I've been researching the issue. Can't remember where now.

Just so everyone reading this understands the system. The eccentric shaft/valvetronic changes the lift height of the valves. It has nothing to do with timing/when the valves open (you can argue at max lift they open earlier/close later).

The shaft spins back and forth to increase/decrease the valve lift. This system actually is in place of a traditional throttle body. The only way the shaft can be damaged is if it is not properly lubricated under the caps that hold it down. This can come from debris getting in the way as well. If the shaft can't spin freely it will bind at a specific spot, causing the flat power spot. Basically think of it as the throttle body being stuck at 75% for a second when you are requesting 100%. This can also happen when the servomotor goes out as it is not able to spin the shaft properly (in the event the shaft is fine).

All that said, there is a really good chance if caught early, you can just pull the shaft, clean it up and relube it. If you see obvious damage then you should replace it. The more you drive it the more likely for damage that will need a new shaft.