Is yours noisy, is the valve bent, is there a few pages of 'story' behind this?
I won't post the links to your long stories of woe, but rather ask that you do the members here the courtesy of posing a question in context. Bring up the old threads, with all the background, and ask for help with the next step.....
Geez...
Hi ARD,
I just didn't want to bore everyone here with my long story. But here it is
Back in June, I need to have my timing chain components all replaced because I have a broken timing chain guide. There are metal filings in the oil system from timing chain rubbing the guide, dealer told me to replace the engine at my cost. I said no because the car had good compression, doesn't have a rough engine idling, and no computer code had came out. After the timing chain replacement (we waited 2.5 months for parts), the engine stalled. According to the dealer, the engine did ran for 30 mins before stall.
The following report was written by Hans, the inspector who work for the local motor association. Motorline BMW didn't want to write a report, but they assisted Hans.
I have read the comments made by the other M5 owner and have thought about it and I feel that he is correct on some points.
(1) The Engine Control Unit (ECU), camshaft sensors and Vanos control valves control the position (angle of advance or retard) of the camshaft in relation to the timed timing chain sprocket. The timing chain sprocket, crankshaft and camshafts will all be synchronised and remain so if the basic setup had been followed. (Please disregard the fitment the Vanos system here for the moment) I believe that Motorline has set up these components correctly otherwise the engine would not have run following the completion of the timing chain replacement and the engine would have been damaged when the engine was first turned over.
(2) We have been advised that the Vanos system has to be set to a default position before fitment to the engine. This procedure involves applying compressed air to an oil hole in the Vanos unit and that this should position both the camshaft position actuators in their default position. The Vanos unit is then inserted into the camshafts and secured. If the Vanos system is functioning normally the engine will run as designed. Assuming that the the Vanos unit is in the default position, if for any reason the camshaft sensor or Vanos control valves malfunction, then the worst case scenario would be that the engine would run rough. (ie. its operating parameters have not been breached.)
(3) In the case with your vehicle, we believe that the Vanos exhaust camshaft position actuator was not in the default position and was in effect stuck in an advanced position. This would have allowed the engine to be started and the engine would have been running well whilst the exhaust camshaft position actuator was stuck in the advanced position. However, if the exhaust camshaft position actuator suddenly managed to free itself due to the action of oil pressure, heat (as the engine warmed up) and some normal engine harmonics together with the control components directing the camshaft actuator to move to the retarded position (as would be the case above idle speed), then this retardation could result in a greater exhaust valve overlap and corresponding higher exhaust valve lift than normal near Top Dead Centre. This greater than normal exhaust valve lift near Top Dead Centre in turn would be in conflict with the engine cylinder's pistons and they could touch resulting in bent valves.
(4) We have been advised by the repairer that there are no checks that can be made on the Vanos unit itself to ascertain the position of the exhaust camshaft position actuator. It would also be timely to mention the oil and metallic swarf as other contributing factors to the Vanos malfunction. The Vanos unit is normally replaced as a complete assembly.
I doubted the engine ran for 30mins, but have no proof.
Another point is that I did asked consultant in Motorline back in Aug 08 (this is while I am waiting for the timing chain parts to arrive) about replacing my Vanos together with timing chain (because I can save on labour cost), to my surprise, they said no. And now they blame on the Vanos was faulty and caused all these bent valve.
I also have enough evidence to show that my Vanos was working except it was making some noise. Just before the timing replacement, I had compression test done and were all good, not idling rough, and no code ever came out from the computer. So it is only setup error that can cause these valves to be bent.
The reason I opened this thread is that once I am sure that the Vanos failure alone will not cause bent valve, I am taking legal action against the dealer. Dealer is towing my car back to me tomorrow. We already spent 4 weeks trying to sort this issue out. Now they don't want to touch it anymore.
Nelson
