The Stovebolt Site Forums The Shop Area Engine Shop Thermostatic spring

Hello,
how should the thermostaic spring works?
My knowledge is, the spring should keep the flap closed if the engine is not warm and should the flap open, if the engine is warm.
And now my question:
If I heat the spring, the spring turns and the spring leaves the the anchor pin. Is this normal or should spring rake to the anchor pin?
An another question, the springs they are offered have 5 coils, the spring that was me sold have 9 coils and is ver smart. Which one is the better one?
Ask
Wolfgang

Hello Wolfgang,
Please see the attached images. I hope you can see them ok. This is how the spring should be installed. I do not know if the difference of 9 coils will make any difference. You can use different springs. Some person said here a couple of years ago the spring for the Jeep would work and was much less expensive. Please tell us if you have any questions.

Here's an interesting video of a guy heating it with a heat gun:



The shop manual mentions it... but not much detail
http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0620.htm

Is Uncle Brad our own Brad Allen? He's a wealth of information.

An interesting item in that part of the shop manual says to free it up with kerosene mixed with a little baking soda. Homebrew recipe for penetrating oil??

As far as the spring leaving the pin once heated is concerned, it is not a problem as long as the valve shaft is free. The exhaust flow from the engine will push the valve fully into the warmed up position. All the spring is for is to keep the valve in the cold engine position until the engine warms up.

Any ideas on what to do to keep the spring from coming/falling out of the shaft?

I installed a 1954 Corvette exhaust manifold on my rebuild and the spring I bought keeps falling out. Luckily I have found it each time and didn't loose it out on the streets of Dallas!

Gently pinch together (a little) the slit in the shaft (where the spring-end goes into the shaft).

Warning: those "tangs" can break from too much bending over the years.

A new shaft is available.
But, it can be "interesting" to remove/reinstall.
You need to ream/drill the holes in the manifold.

That '54 Corvette exhaust manifold will never work on whatever engine you put it on, sadly.
If you send me a PM with your mailing address, I will provide my address and send you money for shipping it to me...
On a slightly more serious note, I would make sure that you have the correct spring.
Does it look like the slot which the spring goes in has been spread? I would not try to spread nor mash the slot whatsoever.
In your case, you would be better off making a shim to take up the slack. Stainless steel or copper would hold up fine in that environment.
Carl

I may have been born at night, but it wasn't last night Carl! LOL!

I got the spring from ChevyDuty I believe. Trying to find places for 1953-1954 Corvette parts is pretty hard. I'll try shimming it and see if that works.

Hello,
and another question, how must the weight sit that sits on the shaft, which is controlled by the spring.
Has someone a picture, that show the position of the weight, when the flap is closed or open, if the engine is cold.
Ask
Wolfgang

Wolfgang, the Shop Manual (p. 6-4) has a drawing of the Heat Riser Operation. When the flapper valve is in the closed position, routing exhasut gases up under the intake manifold, the counter weight is horizontal. As the spring heats, the counter weight drops toward the engine, going more vertical.

Doug

Please see the attached image. The weight will look like this when it is cold. There will be spring pressure against it at this point. The weight rotates counter-clockwise (as the arrow shows) when the engine is at normal running temperature.

And here is what the weight will look like when the engine is hot...and an image of the spring. Good luck.

Thank you for your pictures.
Wolfgang

One question,
if the engine is cold the flap of the exhaust manifold is open and if the engine is warm the flap must be closed? Is it right?

Total opposite actually.

Pictures might help?
explanation/description : exhaust manifold heat control valve
explanation continued : with another nice illustration