Ragdoll Physics Broken?

I think I have setup physic assets like 100 times in the Unreal Engine 3 and can’t recall any of the problems I currently have.

When I have multiple spine bones physic animating the body gets all jittery. There are no bones colliding and the contraints are setuped right with variation.
When I only animate from the neck upwards it looks like the head collapses on its neck with having a weight of 100 kg or something.

Any ideas?

Here is a gif that shows it:

Looks like the neck bone is breaking but I don’t see any reason for that other then that the head seems to be 100 kg even though it says 3.3 kg

It only gets worse:

As you can see there I’m animating from the middle spine upwards yet it does some very funky thing were it does not really physic animate it.