Peter,
I'd go with your theory if you had some documentation. Gilly's thoughts on the matter make a lot of sense, because MB does make a 10 degree key. IIRC the OM603 manual says that 10 degrees is the limit.

Roncallo,
Mileage doesn't mean anything on a car. What is important is how the car is driven and how it is serviced. To answer your question, the 380SEC has 130k on the clock, and the 420SEL has 385k.

Kebowers,
For the sake of brevity I used the term chain stretch. I am well aware of the fact that the chain elongates because of wear on the pins and links. Actualy MB has determined that a 10 degree key is still strong enough, because they use one. I agree that the double row chain is very strong and won't fail, but it is not the chain that fails. What happens is the chain gets so long that tha tensioner can't control the whip. The whipping chain beats the crap out of the inner chain rail on the left bank until it breaks off and climbs up the chain to make the cam stop and bend the valves. At least that is how I see it until someone can convince me with a different theory. A few years ago I received a call from someone 50 miles away telling me he heard a sound and then the engine died on his 420SEL. I told him that most of the valves were bent on the left bank and hee might as well get it towed in. That is exactly what the problem was. I do appreciate your input. Thanks.

I'm open to all the help I can get on this one.

Peter

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