[Haus_07]

Hi all. So, like many of you, I have been suffering from the dreaded wastegate rattle for quite sometime now on my 07 E90 335i. Well, late last night I had a light bulb appear atop of my head, and came up with a very cheap and simple fix. It's always been the aft turbo with the problem, so I guess if your gonna have rattling issues, that's the turbo to have it on due to the easy access.

There are 2 main reasons why my wastegate makes noise, and while I was only able to address 1 of those issues, it made quite a bit of difference. The arm that actually goes through a bushing and into the wastegate housing has a little slop between the bushing and the arm itself, and that's the part that I can't do anything about short of taking the entire assembly off and either rebuilding or replacing, but the large amount of movement where the actuating rod attaches to said arm is where I was able to make some progress.
If you look down in the engine bay near the wiper tank filler neck, you can see the vacuum driven actuator, actuator rod, and attach point to the actual wastegate arm itself. Reach down in there (on a cold engine please!!!!) and see how much play you have where the actuating rod attaches to the wastegate arm. If yours is anything like mine, there is an excessive amount of play, and that was the primary source of rattle on my car. The rod end is held on to the arm by a little c-clip, and that's it. The rod end moves around a lot on the wastegate arm, and causes a ton of rattle while not being held tight until vacuum hits the actuator which pulls on the rod.

All I did was pull the little c-clip off, and slide the rod end from the wastegate arm. At this point I did a quick check to make sure the rod was adjusted correctly by moving the wastegate arm to it's full closed position (moving it all the way towards the firewall), then pushing the actuator rod all the way into the vacuum actuator. Now, with both the rod and the wastegate arm at their respective end of motion, you should be able to slide the rod end back onto the arm. If you can't, then the rod end needs to be adjusted to make it shorter or longer so that they line up when both are at their max movement point. Note on this: this adjustment is based on my personal experience and knowledge of how the system works, so if you feel this adjustment criteria is incorrect, please feel free to enlighten me!!!

My adjustment was good, and I could slide the rod end back onto the wastegate arm while they were both at their end of travel, so on to the next part. I have a fairly large assortment of aluminum washers is various sizes and thickness. Through trial and error, I came up with a washer that takes up the extra room on the wastegate arm where the actuating rod end attaches. Now that you have the correct size washer, slide the washer onto the arm first, then slide the rod end on, then re-install the little c-clip. Note: make sure the washer(s) you choose are not to thick, or the rod end will cover the little notch where the c-clip sits, and the rod will just pop off leaving you with a non-working wastegate!!

Once you have everything back together, move the actuating rod through it's range of motion to make sure there isn't any binding. At this point there should be little to no side to side movement of the rod end on the wastegate arm. I then started the car, and sure enough, most of my wastegate rattle was gone!!! Very simple and low cost solution to eliminating a good portion of wastegate rattle!!! I hope this info helps with the never-ending battle to quiet down our cars!! If your having a difficult time understanding what I'm talking about here, let me know and I'll post a few pics for visual clarification. Enjoy!!!

[roadkillrob]

Let us know how it holds up - I think Mr. 5 did a DIY on this a year or 2 ago on his and got rid of all his rattle. I think he ended up with new turbo's eventually, but that may have been due to other things.

http://www.e90post.com/forums/showthread.php?t=176269

Most recently someone posted up that they had a lot of wastegate rattle and the dealer traced it to the vacuum pump not putting up enough vacuum and replacing that also fixed it up.

[chrisw335i]

yeah i just went out and checked mine..and it does have a good amount of play in that location and makes sense it would cause noise..can you give more info on exactly what size washer you used to make this fix even easier and less guesswork..thanks!

[caradd]

Pleaseedityourpostandaddsomeparagraphs!

[chrisw335i]

+1

Originally Posted by caradd

Pleaseedityourpostandaddsomeparagraphs!

[Haus_07]

Originally Posted by caradd

Pleaseedityourpostandaddsomeparagraphs!

Hahahahahha!!! Paragraphs are for pussies!!! Lol!! No, but sorry about that. I usually post from my iPhone, so I only see a small part of the screen while typing (horizontal), and when I get going, I just keep typing away till I'm done!!! I promise that I will put the info into paragraphs next time!!!

As far as the washer goes, I'm in the aviation field, so I have a ton of misc aircraft hardware laying around. The washer I used was for a 3/16 fastener, but I had to run a drill through it several times to open the hole up some so it would fit. Thickness will depend on how much space you need take up before covering the c-clip valley.

I used an aluminum washer (that's all I had), but I think any metallic material will do. I think I would stay away from plastic and the likes due to the amount of heat in that area. Any automotive store or ace hardware will have the washers that you need. If I get a chance tonight, I'll put some calipers on the arm and find out what the true dimension is for the shaft.

By the way, I can't hear any rattle at all now. I think that washer really did the trick, but I guess time will tell!! Let me know if you have any more questions, as I check/read this board often. Happy with the paragraphs now??? :0)

[Rob@RBTurbo]

Does the car still boost ok? I'd assume that your adjustment technique is quite abit off if I read that right. Did you have to make quite abit of adjustment in shortening the rod?

[Haus_07]

Originally Posted by RobBeck

Does the car still boost ok? I'd assume that your adjustment technique is quite abit off if I read that right. Did you have to make quite abit of adjustment in shortening the rod?

I didn't have to make any adjustments to the actuator rod. Awhile back I was lengthening and shortening the rod trying to eliminate the wastegate rattle, but it had little effect. Unfortunately, I never counted the threads for a reference before I started my adjustments, so I had no idea how far away from stock I was.

A few weeks ago I posted a thread asking other N54 owners who had not (knowingly) had any adjustments made to their setup give me a thread count from the locking nut back so I could figure out where I was at as far as length was concerned. Several members replied, and the average was around 26 threads.

Armed with that knowledge, I checked my car, and found that I was pretty far away from average. I was only counting around 15 threads from the lock nut, so my rod was significantly shorter than the majority, which explains why I was seeing increased boost. I re-adjusted my actuating rod back to 26 threads, and locked it in place.

When I pulled the rod end from the wastegate arm last night, I moved both of them to their max closed position (wastegate), and suprisngly enough the rod end lined up with the wastegate arm, so to me that means that at about 25-27 threads the rod length should be right on the money, and no adjustments were required.

The car boosts normally, I don't get any type of codes under WOT pulls, and now I don't have anymore annoying rattles coming from the wastegate assembly. I'm sure that's not the method BMW uses to adjust wastegates, but without any special tooling or taking the whole set up off of the car, it seemed to me to be the simplest way of determining wether or not I was way out on the adjustment. If you think about it, if the wastegate is fully closed, that means that the full amount of exhaust is being directed towards the impeller, and should be max boost for that turbo. By simulating the rod being fully sucked in by the vacuum actuator, the wastegate arm should also be @max travel. That's the way I see it at least, but there are probably other variables involved in properly adjusting the actuating rod.

But, being that I had limited tools available and no real written adjustment procedures, my method was justified when @26 threads showing, as on several other N54's, both the rod end and the wastegate arm lined up perfectly @max travel. So, that's my story, and I'm sticking to it until someone steps in and proves me wrong.(which should be anytime now). Hope that answers your question!!! :0)

[Big Tom]

This is Volkwagens solution for the rattle:

[Haus_07]

Originally Posted by Big Tom

This is Volkwagens solution for the rattle:

Nice!! Now that's using your noodle!! Keeps with my favorite way of doing things..."KISS"..Keep It Simple Stupid!!! You know Tom, that gives me a few ideas. I heard him say he paid $75 for that clip!! I mean, if it works, then by all means, but I think I could come up with something similar for our cars.

I've been an aircraft sheetmetal mechanic for 15 years, and I fabricate all kinds of things. From full on 3' long .250" thick repair doublers, to little clips and things of that nature. I have all kinds of metal stashed in my garage, and I do believe I have some spring steel out there. I bet I could design something with the same concept in mind, although I don't think it would have to be that big. Hmmmmmmm.......I might just go take a look at my actuator and see what can be done. Thanks for the inspiration, man!!!

[Big Tom]

Originally Posted by Haus_07

Nice!! Now that's using your noodle!! Keeps with my favorite way of doing things..."KISS"..Keep It Simple Stupid!!! You know Tom, that gives me a few ideas. I heard him say he paid $75 for that clip!! I mean, if it works, then by all means, but I think I could come up with something similar for our cars.

I've been an aircraft sheetmetal mechanic for 15 years, and I fabricate all kinds of things. From full on 3' long .250" thick repair doublers, to little clips and things of that nature. I have all kinds of metal stashed in my garage, and I do believe I have some spring steel out there. I bet I could design something with the same concept in mind, although I don't think it would have to be that big. Hmmmmmmm.......I might just go take a look at my actuator and see what can be done. Thanks for the inspiration, man!!!

That sounds very promising, keep us updated!

Remember that the wastegate pin is available in both 6 and 8 mm:

[Rob@RBTurbo]

Haus,

I don't feel you are getting the best adjustment using this method. I just tried it myself, and have found that the gates never really close (which is probably why you don't get the rattle, the flapper can never get pulled all the way in enough to rattle against the housing). However, performance may suffer.

I ran a bench test taking a good turbo and feeling flapper movement/play towards zero lash, that contact is made of the flapper at approx. 5.5 in/Hg (which is approximately desired). Using your adjustment method, no matter the vacuum applied you never get to the zero lash/no play point. The actuator actually needs another 1/4" or so of "pull" beyond the point you have found in order to have the leverage to keep tension on the wastegate flapper- to keep it closed and seating on the turbine housing when needed.

Rob

[georgelb]

Originally Posted by Big Tom

This is Volkwagens solution for the rattle:

I like how he just tosses everything over his shoulder.

Loosen bolts; chuck wrench over shoulder. *clang*
Remove shield; chuck it over your shouder. *ting*

[caradd]

Originally Posted by Haus_07

If you look down in the engine bay near the wiper tank filler neck, you can see the vacuum driven actuator, actuator rod, and attach point to the actual wastegate arm itself. Reach down in there (on a cold engine please!!!!) and see how much play you have where the actuating rod attaches to the wastegate arm. If yours is anything like mine, there is an excessive amount of play, and that was the primary source of rattle on my car. The rod end is held on to the arm by a little c-clip, and that's it. The rod end moves around a lot on the wastegate arm, and causes a ton of rattle while not being held tight until vacuum hits the actuator which pulls on the rod.

How can you determine what amount of play there suppose to be? When you start the car the rod is pulled back from vacuum thus eliminating the slack.

I have new turbos/act/wstgates and the play feels the same as it did when I had the rattle.

[Haus_07]

Originally Posted by caradd

How can you determine what amount of play there suppose to be? When you start the car the rod is pulled back from vacuum thus eliminating the slack.

I have new turbos/act/wstgates and the play feels the same as it did when I had the rattle.

The play im talking about is the side to side movement of the rod end where it's attached to the wastegate arm. There was quite a bit of room for the rod end to slide side to side between the c-clip and the vertical face of the wastegate arm, so that's where I put the washer. Now the rod end sits snug against the c-clip eliminating any side to side movement.

[Haus_07]

Originally Posted by RobBeck

Haus,

I don't feel you are getting the best adjustment using this method. I just tried it myself, and have found that the gates never really close (which is probably why you don't get the rattle, the flapper can never get pulled all the way in enough to rattle against the housing). However, performance may suffer.

I ran a bench test taking a good turbo and feeling flapper movement/play towards zero lash, that contact is made of the flapper at approx. 5.5 in/Hg (which is approximately desired). Using your adjustment method, no matter the vacuum applied you never get to the zero lash/no play point. The actuator actually needs another 1/4" or so of "pull" beyond the point you have found in order to have the leverage to keep tension on the wastegate flapper- to keep it closed and seating on the turbine housing when needed.

Rob

Rob,

That's what I was afraid of when I was pushing the actuator rod back and forth. The thought that I had no idea how far the rod actually travels in either direction when vaccuum is applied. So, really I need a vaccuum pump to apply 5.5in/hg vaccuum to the actuator to see the full range of motion, and adjust from there, correct?

So what your saying is that right now you believe that my rod end is really to long, and when asking for full boost, the wastegate is not closing all the way, and I'm not getting the best performance I could from that particular turbo, right? So to get the proper adjustment for my particular car, I would need a vaccuum pump, and apply 5.5in/hg to the vaccum atuator, and adjust the rod end until the wastegate is fully seated in the closed postion? Where does the 5.5in/hg come from? Is that what the DME is requesting under full boost?

Thanks for looking into this, Rob. I definitely want to learn how to set this up correctly, because if it's wrong, I could be losing quite a bit of HP by the wastegate not closing all the way. I wonder though why all the other owners that responded to my other post were saying 25-26 threads from the locknut? If that's the case, then nobody's wastegate's are fully closing!! Maybe it was designed to be that way? I just don't have enough info about the way BMW sets it up to actually understand what they are doing. I assume they have a procedure for adjusting the wastegates, but I don't know what it is, do you?

[Rob@RBTurbo]

Using a vacuum hand pump is the ideal cost affective approach. Downpipes should be off so you can feel the flapper itself go to zero lash against the valve seat when applying vacuum, but you maybe able to accomplish it "close enough" by feeling the lack of "lash" in the wastegate lever itself. That is your call to make.

Essentially you vacuum pump the wastegate actuator to approx. 5.5in/Hg as you feel the play decrease to nearly nothing between the flapper and the housing seat. Once you get to 6in/Hg, there should be no lash and there should be some "resistance" in rotating the flapper as it sits on the seat of the turbine housing. Doing the test several times after adjustment helps get the feel of it and also confirm your results of adjustment. I try to aim for no play and some resistance in turning the flapper around 5.8-5.9in/Hg, and start to feel a little play to no play around 5.6-5.7in/Hg. By 5.5in/Hg the play should be fairly evident. You want to adjust both turbos using the same method. This procedure is something I semi reverse engineered from the BMW TIS, and from bench testing many sets of turbo take offs. If you can find anything better, or seemingly more accurate, let me know because from what I have seen there's not much out there.

About Wastegate Rattle.
First off, every component in these Internal Wastegates wear out. They are JUNK after some mileage.

1) The Flapper is where I believe alot of the more renouned rattle takes place, as it can resonate against the turbine housing seat when its lightly seated or also as it spins while open from the exhaust gas pulses. The clearances in the flapper to the wastegate arm seem to always be VERY worn out, when manually spinning on axis by hand you can hear it rattle as it rotates/flops around.
2) The wastegate arm and internal bushing. These too become very sloppy over time. I believe they can cause some rattle as well, but I dont believe it's as noted as the flapper above. The bushing and arm DO wear significantly though and usually end up binding, which can cause the wastegate arm travel to degrade and perform poorly. It also can cause the flapper to not close all the way which can lead to more rattle. The excess clearances in this area due to wear require further adjustment to the actuator rod. This is why the dealers try to usually adjust the actuators (or replace/adjust them) initially. That is to shorten the rod, making up for the slop in the worn bushing, and allowing the flapper to seat under the defined amount of vacuum. This will buy some time, but certainly does not fix the problem.
3) The Actuator Rod End to Wastegate Lever Pin. This is the part you believe is causing the rattle in your car. I am sure it does contribute to some rattling, but certainly is not all of it. If this is what you are trying to counter, for now, I'd recommend a low load disc spring washer. I haven't tried them myself yet, but I have found a couple sizes I believe would work perfectly to remedy this area of the rattling.
4) All components. Even new there are clearances in these components. Some rattle (a very tiny amount) is somewhat normal. But its when things begin to wear, it becomes intolerable, and they are very prone to wearing all throughout.

[XJS]

Rob, as far as I'm aware judging by all threads on E90post and elsewhere, it's almost always the rear turbo that is rattling. Do you have any idea why the rear turbo is prone to rattling while the front is not? Are the wastegate constructions different?

[Haus_07]

Originally Posted by XJS

Rob, as far as I'm aware judging by all threads on E90post and elsewhere, it's almost always the rear turbo that is rattling. Do you have any idea why the rear turbo is prone to rattling while the front is not? Are the wastegate constructions different?

That is a really, really good question. I've been wondering about thay myself for quite some time now. Same turbo, same wastegate, same actuator, same everything, except the aft one seems to almost always be the culprit?? Why, I ask, WHY????? :0)

[Haus_07]

Originally Posted by RobBeck

Using a vacuum hand pump is the ideal cost affective approach. Downpipes should be off so you can feel the flapper itself go to zero lash against the valve seat when applying vacuum, but you maybe able to accomplish it "close enough" by feeling the lack of "lash" in the wastegate lever itself. That is your call to make.

Essentially you vacuum pump the wastegate actuator to approx. 5.5in/Hg as you feel the play decrease to nearly nothing between the flapper and the housing seat. Once you get to 6in/Hg, there should be no lash and there should be some "resistance" in rotating the flapper as it sits on the seat of the turbine housing. Doing the test several times after adjustment helps get the feel of it and also confirm your results of adjustment. I try to aim for no play and some resistance in turning the flapper around 5.8-5.9in/Hg, and start to feel a little play to no play around 5.6-5.7in/Hg. By 5.5in/Hg the play should be fairly evident. You want to adjust both turbos using the same method. This procedure is something I semi reverse engineered from the BMW TIS, and from bench testing many sets of turbo take offs. If you can find anything better, or seemingly more accurate, let me know because from what I have seen there's not much out there.

About Wastegate Rattle.
First off, every component in these Internal Wastegates wear out. They are JUNK after some mileage.

1) The Flapper is where I believe alot of the more renouned rattle takes place, as it can resonate against the turbine housing seat when its lightly seated or also as it spins while open from the exhaust gas pulses. The clearances in the flapper to the wastegate arm seem to always be VERY worn out, when manually spinning on axis by hand you can hear it rattle as it rotates/flops around.
2) The wastegate arm and internal bushing. These too become very sloppy over time. I believe they can cause some rattle as well, but I dont believe it's as noted as the flapper above. The bushing and arm DO wear significantly though and usually end up binding, which can cause the wastegate arm travel to degrade and perform poorly. It also can cause the flapper to not close all the way which can lead to more rattle. The excess clearances in this area due to wear require further adjustment to the actuator rod. This is why the dealers try to usually adjust the actuators (or replace/adjust them) initially. That is to shorten the rod, making up for the slop in the worn bushing, and allowing the flapper to seat under the defined amount of vacuum. This will buy some time, but certainly does not fix the problem.
3) The Actuator Rod End to Wastegate Lever Pin. This is the part you believe is causing the rattle in your car. I am sure it does contribute to some rattling, but certainly is not all of it. If this is what you are trying to counter, for now, I'd recommend a low load disc spring washer. I haven't tried them myself yet, but I have found a couple sizes I believe would work perfectly to remedy this area of the rattling.
4) All components. Even new there are clearances in these components. Some rattle (a very tiny amount) is somewhat normal. But its when things begin to wear, it becomes intolerable, and they are very prone to wearing all throughout.

Rob, thanks for taking the time to explain where the rattle is coming from, which parts do the rattling, and how to properly adjust the wastegates!! I understand everything that you said in your reply, and I now have a crystal clear picture in my head of what's going on inside there.

Is there a rebuild kit made for the wastegates? Possible new bushing, wastegate arm, wastgate disk and associated hardware/seals? I'm way out of warranty, and have been building/repairing/restoring cars for the last 25 years. Taking things like this apart doesnt' scare me one bit, and being on a tight budget, would really be the only option for me.

If there is a rebuild kit out there, I'm going to start looking for it ASAP, because I have another reason that one (if not both) of my turbos are going to have to come off. After a spirited session of driving the other day (100 octane and map7) when I came to a stop light near my house, the entire side of my car was enveloped in blue smoke!! One of my turbo oil seals is leaking, and although it doesn't blow smoke all the time, it's days are for sure numbered.

I found this: http://baeturbosystems.com/turboserv...acement-2.aspx

The link is to a rebuild kit for our OEM turbos, and comes with the oil seals and other misc. parts. Since I'm not experincing any whining or howling, plus my turbos are putting out over 17lbs psi when running on race gas, seems to me that I really just need to replace the oil seal. Do you concur with this line of thinking? So, if I could also find a similar wastegate rebuild kit, then while I had the turbo(s) off, I could rebuild the whole damn thing!! Best part of that BAE repair kit is the price; $60ea. x 2!!!

I've got no problem putting in the wrench time; actually I quite enjoy it because I like to see how things work first hand, and the more shit you take apart, repair, and put back together correctly just adds to the database in my head!!! Are there special tools required to pull a turbo or a wastegate apart? Looking at the blow up view on BAE's website, it looks pretty straight forward, but I'd hate to get into it and find out that I don't have a specific tool to complete the job. Thanks for all your help Rob, and if you've got any knowledge of a wastegate repair kit similar to the turbo repair kit, I'd love to see what you've got going on!!! Thanks again man for the time you spent on the entire breakdown. It shows that you are one of those people that have no problem sharing their knowledge to help someone else in their own endevors. I'm finding that to be harder and harder to come by nowadays, so I really do appreciate it!!

[TommyLights]

Just checked mine and the C clip seems to have fallen off on its own. This means there is even more slop than usual....anyone have an idea of what replacement clip looks like and what size I should be getting? I am thinking to put a new clip on with the washer at the same time. I tried putting in a very small rubber o-ring just to check the tolerance and it is very tight there.