N55 eccentric shaft,valvetronic motor

 Ok this is going to be a long post with a lot of pictures,,,,N55 check engine light on,,,,faults were valvetronic motor and valvetronic won’t reach its limit,,,,performed the test plan,,,operated the valvetronic motor test which passed the test twice,,,but when I started the engine it would fail again ,,,,which tells me all these BMW test are not always correct,,,,lol,,,after more testing it finally said the valvetronic motor and the eccentric shaft should be replaced ok,,,,now the fun started. Here you can see I already removed the fuel injectors and the 3 injector and spark plug stands,,,you have to remove them to gain better access to the valvetronic motor,,,,,also notice the oiler line,,,,you should also replace this at the same time.  Here you can see all the injector and spark plug stands removed. Now the fun started,,,during inspection I found the intake camshaft lobes pitted,,,only cylinder 5 and 6 were pitted,,,,we have no idea what caused this or what happened,,,,now are repairs have changed,,,,we are going to replace the valvetronic motor,eccentric shaft,roller rocker arms and eccentric levers. Here the valvetronic motor which is just a worm gear ,,,,,which can move the eccentric shaft very fast.now here is one of BMW over engineered tools needed to remove and install the the eccentric shaft lever springs,,,,you need this tool to perform this job,,,,there is no other way to do this without hurting yourself.,,,even with this tool you can hurt yourself,,,,,there is a lot of tension on those springs. Here is the new intake camshaft and eccentric shaft,,,,you can see the gear on the eccentric shaft which locks into the valvetronic motor.  When replacing the eccentric shaft there are also 6 needle bearing that have to be replace,,,,the needle bearing and the 2 bearing half shell bearing.this I show you replace them,,,,,they are a split open,,,,you carefully spread them open over the eccentric shaft and make sure they spin freely. Here are all the new eccentric shaft levers. When replacing the levers and the roller rocker arms,,,,they all have numbers on them,,,,,so when you order new ones you need to know what the number is in the engine now,,,,the levers and the roller arms are both 02. Here is the roller rocker arm you can see number 2 stamped in it. . Her is the final assembly ,,,what I also forgot to say the vanos gear is removed,,,,because you will be timing the engine,,,,once your done you hope it starts,,,,you also have to perform a teach in for valvetronic motor ,,,,it performs about 50 test without it failing,,,,if it fails you have to start the test all over again.

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23 Responses to N55 eccentric shaft,valvetronic motor

  1. kr4va says:

    wow, what a post,, pitting- surface hardness processs issues?


  2. bmw535blog says:

    Hi bmwtechnician. After remove valvecover it’s easy to replace the valvetronic motor?
    Thanks. John.


    • No it not that easy,,,,you have to adjust the eccentric shaft so you can get to all the bolts and so you can slide it out,,,there isn’t that much room to get it out once you take the valve cover off,,,,you have to take out the injector stands and maybe the injector.


  3. Darkstar says:

    Do the car had an uneven acceleration and lack of power? If I disconnect the electric valvetronic motor, my ECU goes in limp mode, but the acceleration is much smoother and der rough idle is completely gone. To avoid the limp mode, I have used EDIABAS/INPA to open the valves to 99% manually. If I do this, the car runs much smoother and faster! Do you think it could be the electric motor? It passes the valvetronic test on Rheingold every time …


    • It could be your problem,,,,do you have any faults


      • Darkstar says:

        I have rough idle(which is gone, if I disconnect the VVT motor), juddery acceleration(especially in low RPM range, which is almost completely gone, if I disconnect the VVT motor) and the power delivery is very uneven + lack of torque. The ECU is empty, no codes have been thrown …

        It seems like a valvetronic problem, but I’m not sure, because I have no codes …
        And I don’t want to disassemble it just4fun, because I know how much work has to be done -.-


      • I understand,,,,but I can’t be 100% that’s your problem,,,,it a very tuff call,,,,it could be something else,,,,,,like a vanos unit going bad?,,,,,,I just can’t make that call


  4. Don says:

    Great write up, thanks for sharing. Did you use Rheingold to re-teach the valvetronic motor? I am having trouble finding the calibration procedure, so will appreciate any suggestions. Background: clicking sound when unlocking/locking the F30 BMW, N20 engine. Errors: 135608 Valvetronic system no movement detected, 135808, and 135B11, all valvetronic related. Can turn the shaft by manually rotating the valvetronic motor eccentric gear via an allen wrench. When hooking up a spare valvetronic motor, its eccentric gear moves without any clicking sound. I suspect the valvetronic motor needs to be replaced. Do you need to use the fancy tool to replace the valvetronic motor or it can be changed without removing lever springs?


    • Don says:

      Please disregard the replacement part of the question since I have found it via 11 37 020Removing and installing/replacing servomotor for eccentric shaft (N20, N26). Would still appreciate the adaptation/re-teaching procedure. Thanks.


    • You can remove it without removing the springs,,,,,it’s a tight fit,,,,no I used ISTA to calibrate the eccentric shaft motor,,,there should be some kind of teach in procedure


  5. Wank says:

    My 335i n55 start but wont turn on. Dtc 2dc5, 2dcf, 2dc6, sometimes the car start and run but after a while the same problem. I’ve replaced the valvetronic motor.


  6. Wank says:

    Yes engine run before, but sometimes same issue. Quick fix, disconnect battery and sometimes the engine will run.

    Now: car start but no run. Could it be the eccentric shaft or camshaft?


  7. Wank says:

    Without any dtc? I will check the vanos units


  8. Wank says:

    DME failure, I’ve replaced the DME. Thanks!


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