Exhaust manifold valve???

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May 3, 2012
Savannah, GA
I have this flapper valve in my exhaust manifold rite before it goes to the exhaust pipe. Looks like it used to have some kind of thermal spring on one end and the other is like an "S" cam. Is there supposed to be a linkage hooked to this "S" cam to control something or .......... what?

Bout to hit the sack.... Will post pics tomorrow morning to show if not certain of what I'm describing

It routes exhaust heat to the bottom of the intake manifold when the engine is cold to warm it, reducing fuel puddling (condensation) in the intake manifold. As the engine heats up, the thermostatic spring opens the valve, routing exhaust heat away from the base of the intake. the "s" cam is just a counter balance weight. Nothing hooks to it.
Here is the pic... It's kinda hard to see if you don't know what to look for but I think I got my answer in the above post thanks


Manifold with "S" cam... Is there any way to remove this or is it best to repair the thermal spring? I want to install some headers but also want to keep it all original. I want to drive it like it came off the assembly line. If headers will benefit me in some way I will go that route. For now the valve spring is broken and I had to soak it in PB Blaster to get it to even move.
The spring will eventually rust through and break, causing the valve to be stuck in a position that diverts the exhaust under the intake all the time, eventually cracking the bottom of the intake manifold.
So ..... Can it be removed? Or what? If I remove it I thought I could maybe weld up the holes.

If you do it, please post up the results. This comes up and I haven't seen a good solution. I heard the other day that the big weld on the cast iron wouldn't last because of the different expansion characteristics. Maybe a carriage bolt would fit into each hole from the inside?
Ill be removing it this weekend and will do a write up with pics on it. I like the carriage bolt idea.

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