Exhaust manifold heat riser: Did I do this right?

Well, took the car out to dinner tonight. Checked when we got to the restaurant and again when we got home. If anything, the spring got LOOSER as it warmed up and the flapper didn't seem to be doing anything.
Does that mean I need to try and wind it tighter?
That's how it works. It loosens up to allow the valve to open more when it's hot. Was the valve just hanging open?