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Old 10-03-2012, 08:50 AM
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Fudman Fudman is offline
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Location: Sudbury, MA
Join Date: Apr 2007
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Mein Auto: '02 530i Sport auto
Originally Posted by Tiko530 View Post

1. When I first lifted the Vanos unit out of it's spot I noticed what looked like black flat seal or o-ring of some sort, it was broken and pretty much flattened out into its lenght, half was underneath the lower part of the timing belt and the other half was sticking out when I took the Vanos out. It was flat, about 3 mm wide and seemed like hardened rubber, not much different than the teflon seals on the Vanos pistons but significantly wider. I am only giving this description because I looked in the area but could not figure out where this had come from and till now have no idea what purpose it served. I removed it.

2. During the removal of the bolts holding down the Vanos exhaust piston and spring the piston flew out under the pressure of the spring and fell about 3 feet down to a concrete floor. I inspected the piston and did not find any significant damage though.

3. One of the Vanos piston caps was slightly damaged during removal. A small section of the side wall of the piston cap (less than 1/4 of the circumference) broke off, I reinstalled as it was and it went back in its place normally.
1. Do you have a picture of this? This sounds like your teflon Vanos piston ring although there is no way it could get into the the timing chain area. It was probably a section of your valve cover gasket. These get plasticized and very brittle and crack apart during VC removal.

2. When you say "no significant damage", how bad was the piston "damage"? Pictures? The pistons are aluminum and dent and scratch very easily. Any compromise to the surface can affect the seal, which can then affect engine timing.

3. Lastly, if the slot that the O-ring sits in, on the Vanos piston cap was damaged, that would cause a possible leak in the system. Pictures?

Last edited by Fudman; 10-03-2012 at 08:52 AM.
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