Exhaust Heat Risor Valve ?

[RossL]

My valve does not move unless I move it by hand. Is the valve/flap open when the weight is up or down?

I consider the top picture "up"

[DynoDan’55]

I forget (replaced mine with spacer). But, I do remember that in the original exploded parts diagrams, it was accidentally drawn upside down.

[55Greg&Amy]

Open when down

[MarkR]

If it starting to give you trouble and you don’t drive it in very cold weather you can replace it with a spacer from one of our suppliers.

[ward 57]

There is a bi-metal spring on that valve which opens the valve when it gets hot from the exhaust. They do loose that ability when old. New valves are basically unavailable so many just install the spacer. When I had my new exhaust system installed I didn't have time to order the spacer so the fellow just locked it open.
It only takes a couple of extra minutes longer to get the choke to pull off.

[paul2748]

I have two cars that originally used the heat control valve, a 54 Ford and 56 Bird. Removed both of them and used the spacer. I have not noticed any difference on the car getting warmed up.

[RossL]

Since the exhaust on my car is one of the few things I don't have to work on, I'm just looking for a temporary solution. I plan on using some wire to open the flap for now until I have more time, at that point I will probably install the spacer.