[TheFanatic]

Originally Posted by weehe126

.

So this could ultimately be a carbon buildup precursor and the type of normal driving the car gets is ultimately the root cause.

[weehe126]

Originally Posted by TheFanatic

So this could ultimately be a carbon buildup precursor and the type of normal driving the car gets is ultimately the root cause.

I have no idea where you got carbon build up from. The only way you should get carbon buildup in the head to cause an issue is from 20k mile oil change intervals.

[therealm3]

Originally Posted by weehe126

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.

Thank you for the detailed explanation. Good to know how things work.

So, to your point about lubrication being the possible issue; I wonder if the previous owner of my car should have been doing more frequent oil changes? Or maybe I should be using a different oil than the factory stuff. It's supposed to be pretty good based on what I have read, but who knows? Or is this just bad design. BMW is not perfect so that is very much a possibility. (Think rod bearings in M cars, N54 turbos, etc.) I have toyed with switching to Red Line at my next oil change and may go forward with that.

[TheFanatic]

Originally Posted by weehe126

I have no idea where you got carbon build up from. The only way you should get carbon buildup in the head to cause an issue is from 20k mile oil change intervals.

Having building up on the valves would put extra load on that shaft, which could be a reason as to why it's wearing out faster on some vehicles but not others.

Didn't think I had to specify that but I was wrong, my bad. If you're still confused as to where carbon build up comes from I can link you to the N54 groups

[weehe126]

Originally Posted by TheFanatic

Having building up on the valves would put extra load on that shaft, which could be a reason as to why it's wearing out faster on some vehicles but not others.

Didn't think I had to specify that but I was wrong, my bad. If you're still confused as to where carbon build up comes from I can link you to the N54 groups

The eccentric shaft does not lift the valves. It moves an intermediate part so that the camshaft increases and decreases valve lift. Didn't think I had to further explain how valvetronic works, my bad.

If you knew anything after the N54 you would realize carbon build up hasn't been a major issue since. N55s don't even need it after 100k miles.

[weehe126]

Originally Posted by therealm3

Thank you for the detailed explanation. Good to know how things work.

So, to your point about lubrication being the possible issue; I wonder if the previous owner of my car should have been doing more frequent oil changes? Or maybe I should be using a different oil than the factory stuff. It's supposed to be pretty good based on what I have read, but who knows? Or is this just bad design. BMW is not perfect so that is very much a possibility. (Think rod bearings in M cars, N54 turbos, etc.) I have toyed with switching to Red Line at my next oil change and may go forward with that.

The only part I am not sure on is how the shaft is continually lubricated, if it even is. BWM calls for "long time lube" be put in the caps/shaft on assembly.

[therealm3]

Originally Posted by weehe126

The only part I am not sure on is how the shaft is continually lubricated, if it even is. BWM calls for "long time lube" be put in the caps/shaft on assembly.

Interesting. Well, that may be the design flaw. A lack of lubricant. If this is the case, then maybe those of us with the issue had motors that were under lubed at assembly? I sure hope my new shaft was lubricated properly.

[TheFanatic]

Originally Posted by weehe126

The eccentric shaft does not lift the valves. It moves an intermediate part so that the camshaft increases and decreases valve lift. Didn't think I had to further explain how valvetronic works, my bad.

If you knew anything after the N54 you would realize carbon build up hasn't been a major issue since. N55s don't even need it after 100k miles.

so let me get this strait, if the valves were stuck in place and didn't move at all past 50%, that eccentric shaft would have exactly zero more load than normal in trying to move that intermediate shaft to 100%? A part directly responsible for how far the valves travel is not effected by anything the valves are doing in the slightest. If that is the case let me know.

My understanding of how valvetronic works, it would have more pressure on the shaft if the valves had buildup and there was more friction in the full travel length which would show itself after long term driving under a specific throttle range and then going to wide open after build up occurred. some pictures of the wear would be nice

while carbon build up isn't normally a problem with the n55 or b58, that doesn't mean it doesn't happen like you're suggesting. Faulty components can always lead to carbon build up. With the added piece of mind that we as B58 owners have of not worrying about carbon buildup, it also prevents us from catching other symptoms that would show up in the intake because we simply don't check it.

With so many B58s reaching that 100k mile mark we are reaching completely unknown and untested waters, the truth is we have no idea why it is happening and we're guessing.

in case anyone needs the visual here is a nice video.

[weehe126]

Originally Posted by therealm3

Interesting. Well, that may be the design flaw. A lack of lubricant. If this is the case, then maybe those of us with the issue had motors that were under lubed at assembly? I sure hope my new shaft was lubricated properly.

If you watch the video on page 1 there is a part just after the intake cam removal that shows the eccentric shaft come out. If you look closely you can see there are no oil holes like you see for the exhaust cam shaft. I've been trying to find real pictures, but all I can find are diagrams. The shaft looks to be held down by 6 caps, one on each cylinder. This isn't a high speed part like a camshaft, so not having oil constantly blasted at it shouldn't be an issue. But then it comes back to is any oil dripping down between the shaft and caps, or is the "long time lube" the only real lube for it's movement. With how limited this issue is it might just be bad assembly from the factory.

[weehe126]

Originally Posted by TheFanatic

so let me get this strait, if the valves were stuck in place and didn't move at all past 50%, that eccentric shaft would have exactly zero more load than normal in trying to move that intermediate shaft to 100%? A part directly responsible for how far the valves travel is not effected by anything the valves are doing in the slightest. If that is the case let me know.

My understanding of how valvetronic works, it would have more pressure on the shaft if the valves had buildup and there was more friction in the full travel length which would show itself after long term driving under a specific throttle range and then going to wide open after build up occurred. some pictures of the wear would be nice

while carbon build up isn't normally a problem with the n55 or b58, that doesn't mean it doesn't happen like you're suggesting. Faulty components can always lead to carbon build up. With the added piece of mind that we as B58 owners have of not worrying about carbon buildup, it also prevents us from catching other symptoms that would show up in the intake because we simply don't check it.

With so many B58s reaching that 100k mile mark we are reaching completely unknown and untested waters, the truth is we have no idea why it is happening and we're guessing.

in case anyone needs the visual here is a nice video.

If you actually watch the video you posted you would see there is no force on the eccentric shaft. The shaft moves the rocker so that the camshaft pushes more or less of the rocker to push the valve open. The only force it has on it is from the Y-spring (not the valve spring) that holds the assembly together.

Your understanding of carbon build up is also wrong. It causes the valve seat to get buildup causing turbulent and reduced airflow into the cylinders. Valves are pushed open, how could they "get stuck at 50%"? If a valve gets stuck, it breaks or takes the camshaft out with it.

[G.Newt]

Confirming I started experiencing this noise and it's coming from the engine area exactly as Supr3me has. I'm also wondering what's the long term effects. I'm out of warranty and modified. I haven't noticed any driving irregularities and it also idles fine. Just the buzz is annoying.

My oil analysis came back great so I don't think it's related to my maintenance?

[G.Newt]

I was packing and had the trunk open for awhile in the garage. As soon as I closed it, I got the buzzing but it went off clean and no wine down noise that's similar to Supr3me and what I experience after running the car. I'm moving to another garaged location so I'll keep an eye on the issue.

I also have no codes, just in case it would throw something.

Update: Seems anything from N20 to the N55 and even S55 can have this issue. Luckily, if it gets bad enough, it'll throw a code. If the car detects a problem with variable valve timing, it'll fall back to using the throttle body. So I won't destroy the motor.
If my eccentric shaft is pitted, I'll drop the $3-$3.5k and have it done. Hopefully it's just the servomotor like most cases.

[jackstrath]

Supr3me Have you carried this out yet?

[Supr3me]

Originally Posted by jackstrath

Supr3me Have you carried this out yet?

I just replied to a pm from G.Newt on this but no - I'm a quitter lol. After doing my due diligence and seeing the costs involved I ended up shopping the car around. I got a killer trade-in offer from my local dealership (as much as I was being offered private party) and traded it in on a brand new X3M .

Still following this thread tho, as I'm curious if this turns out to be a more widespread issue for Gen 1 B58.

[john_f30]

Originally Posted by Supr3me

I just replied to a pm from G.Newt on this but no - I'm a quitter lol. After doing my due diligence and seeing the costs involved I ended up shopping the car around. I got a killer trade-in offer from my local dealership (as much as I was being offered private party) and traded it in on a brand new X3M .

Still following this thread tho, as I'm curious if this turns out to be a more widespread issue for Gen 1 B58.

Congrats on your new X3M!!

My apologies I forgot to update you guys. I got the car back from the dealership. Took about a week and couple days to replace the eccentric shaft. Everything is covered 100% since I still have the extended warranty on the car. Power is smooth through out and pulls stronger. Doesn't have that flat spot that I was experiencing before. Night and day difference. It took me 3 tries to convince them it's the shaft. All worth it.

[G.Newt]

Originally Posted by john_f30

Congrats on your new X3M!!

My apologies I forgot to update you guys. I got the car back from the dealership. Took about a week and couple days to replace the eccentric shaft. Everything is covered 100% since I still have the extended warranty on the car. Power is smooth through out and pulls stronger. Doesn't have that flat spot that I was experiencing before. Night and day difference. It took me 3 tries to convince them it's the shaft. All worth it.

Congrats on getting it fixed! Would it be possible for you to post the work order? Did they just replace the shaft or the servomotor as well? Thanks!

[G.Newt]

Big ups to therealm3 for the parts list. I'm going to order all of the ones listed + the valvetronic motor this weekend and have a local shop replace both in the next few weeks. Parts look to be about $1,300 or so. 20 hours of labor seems accurate.

[john_f30]

Thanks! Yes they replaced the shaft and servo motor. They upgraded the firmware as well at no cost. Sorry I left the work order in the glovebox and the car is back at the dealership for minor cosmetic repair. Saw a door ding that wasn't there before. They are taking care of that too.

[therealm3]

Happy to help and glad to hear you guys are getting your motors fixed and having the same results as me. It really does feel so much better and more lively now.

[G.Newt]

Originally Posted by john_f30

Thanks! Yes they replaced the shaft and servo motor. They upgraded the firmware as well at no cost. Sorry I left the work order in the glovebox and the car is back at the dealership for minor cosmetic repair. Saw a door ding that wasn't there before. They are taking care of that too.

Would be good to see your work order as well to confirm all the extra parts. I'm gonna talk with my shop first thing Monday morning and go from there. I suspect I'll be one of the first to do it outside of warranty. I'll keep you guys updated.
I'm attached to the damn car. That 6MT life lol.

therealm3 Do you guys also have one for the servo motor? Anything else extra besides just replacing that? No new bolts or gaskets they recommend? Much appreciated.

[G.Newt]

Update: had a short, but spirited drive followed by some highway cruising. Total drive time was 11 minutes. Car was already halfway warmed up when I started it. Parked it in the garage and didn't hear any buzzing/clicking. This is frustrating because now it's intermittent. I wonder if I increase the driving time, can I always produce it.

It was happening pretty often but not every time. Trying to find a pattern/correlation. I'm worried that it won't do it at the shop and since there's no codes, there's nothing they can really do (not paying $65 for a diagnostic when I know what to replace).

Going to track the frequency and try to get some more data. I fully intend on replacing it + servomotor, but while it's "broken" (car still drives/idles fine), I figure trying to RCA the issue could help someone down the line.

[StannisBaratheon]

Originally Posted by G.Newt

Update: had a short, but spirited drive followed by some highway cruising. Total drive time was 11 minutes. Car was already halfway warmed up when I started it. Parked it in the garage and didn't hear any buzzing/clicking. This is frustrating because now it's intermittent. I wonder if I increase the driving time, can I always produce it.

It was happening pretty often but not every time. Trying to find a pattern/correlation. I'm worried that it won't do it at the shop and since there's no codes, there's nothing they can really do (not paying $65 for a diagnostic when I know what to replace).

Going to track the frequency and try to get some more data. I fully intend on replacing it + servomotor, but while it's "broken" (car still drives/idles fine), I figure trying to RCA the issue could help someone down the line.

Maybe let it sit overnight so you can try to hear it on cold start? What's your mileage? I've almost got 60k on my 2016 340iX and have already had the turbo and water pump replaced.