Originally posted by boadly
View Post
I have added an educational pdf file for BMW VANOS systems to this post. Take a moment to read it as this might clear up your question. Especially if you look the at the hydraulic diagrams.
For instance, on page 46 you can see the hydraulic system of the S50B32 engine. OK not an S54 but hydraulic wise I don't expect much differences.
You can see that the piston to move the shaft has 2 diameter. A small area which is pressurized all the time and the big area that is controlled by 2 valves. Instead off routing the oil fluid from 1 to another side the choice is to release oil or add oil on the bigger side.
Since the "controlled" side is bigger more force will be applied against the other side.
I suspect that the "dichtheid" test sets the camshaft to 1 position and doesn't actuate the control solenoids for a certain amount of time. If you look at the hydraulic diagram no fluid should escape and the position should be maintained under ideal conditions. It might be possible that the seal(s) within the shaft/piston are not sealing perfectly causing oil to escape from one to another "chamber". Another option is that one of the solenoids is not perfectly closed. If you look at the solenoids in the S62 engine (E39 M5) these have filters around them. They tend to break by time and the debris of the filter can get stuck in the solenoid. This will continuously feed oil or release oil fluid. With the "dichtheid" test this can be checked.
For your test, did you do it with hot or cold oil? Cold oil can "seal" more as it is thicker. In your case you could opt to replace the sealing(s) around the shaft(s). I believe this is the easiest. If this doesn't solve the issue one or more solenoids might not seal properly. The S54 has a solenoids block. You can remove it and ultrasonic clean it while "activating" the solenoids with a magnet. I personally wouldn't care to much with the "dichtheid" test as long as the activation time is within <300ms. But if you want to test to pass you could do the things I mentioned.
Hope this clears things a bit up
Comment