I can almost see what happened:
I replaced my head gasket myself too.
At the very least, you did not time the cams correctly. It requires a certain procedure. These are interference engines in that the valves will contact the pistons if not properly timed. I assume the incorrect timing caused valve interference enough to snap the chain. It might also have damaged the head to the point where a water canal was breached. Coolant coming from the Vanos is not right at all, as only oil goes in and out of there.
This is really the worst case scenario. The head must come off again, the head inspected and fixed, if even possible, which I question. Valves need to be replaced and re seated. Also inspect the Pistons for damage, though this would be obvious. You can also buy a used head. Some are out there for a few hundred. You will also need a new head gasket and bolts.
But you have to blame yourself for not knowing about the necessity for timing the cams. This is critical and I redid it like 5 times....
My engine runs like a champ now, smooth as butter.
Last edited by tommytoyz; 11-08-2011 at 02:24 AM.