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Posted By: wokri Thermostatic spring - Fri Jun 12 2020 10:16 AM
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
Posted By: Jon G Re: Thermostatic spring - Fri Jun 12 2020 12:44 PM
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.

Attached picture MVC-062F.JPG
Attached picture MVC-061F.JPG
Posted By: Ott3r Re: Thermostatic spring - Fri Jun 12 2020 01:56 PM
Here's an interesting video of a guy heating it with a heat gun:

https://www.youtube.com/watch?v=5wDV4wIM6Vw

The shop manual mentions it... but not much detail
http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0620.htm
Posted By: klhansen Re: Thermostatic spring - Fri Jun 12 2020 06:27 PM
Originally Posted by Ott3r
Here's an interesting video of a guy heating it with a heat gun:

https://www.youtube.com/watch?v=5wDV4wIM6Vw
Is Uncle Brad our own Brad Allen? He's a wealth of information. thumbs_up

Originally Posted by Ott3r
The shop manual mentions it... but not much detail
http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0620.htm
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??
Posted By: 52Carl Re: Thermostatic spring - Sat Jun 13 2020 02:17 AM
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.
Posted By: ApacheFiend Re: Thermostatic spring - Sat Jun 13 2020 05:26 AM
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!
Posted By: tclederman Re: Thermostatic spring - Sat Jun 13 2020 12:16 PM
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. [chevsofthe40s.com]
But, it can be "interesting" to remove/reinstall.
You need to ream/drill the holes in the manifold.
Posted By: 52Carl Re: Thermostatic spring - Sun Jun 14 2020 01:11 AM
Originally Posted by ApacheFiend
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!
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... smile
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
Posted By: ApacheFiend Re: Thermostatic spring - Sun Jun 14 2020 05:13 AM
Originally Posted by 52Carl
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... smile
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.
Posted By: wokri Re: Thermostatic spring - Wed Jun 17 2020 06:47 PM
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
Posted By: drdoug Re: Thermostatic spring - Wed Jun 17 2020 07:06 PM
Wolfgang, the Shop Manual (p. 6-4) has a drawing of the Heat Riser Operation [chevy.oldcarmanualproject.com]. 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
Posted By: Jon G Re: Thermostatic spring - Wed Jun 17 2020 07:13 PM
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.

Attached picture heat riser.jpg
Posted By: Jon G Re: Thermostatic spring - Wed Jun 17 2020 07:20 PM
And here is what the weight will look like when the engine is hot...and an image of the spring. Good luck.

Attached picture MVC-094F.JPG
Attached picture MVC-093F.JPG
Posted By: wokri Re: Thermostatic spring - Thu Jun 18 2020 04:13 PM
Thank you for your pictures.
Wolfgang
Posted By: wokri Re: Thermostatic spring - Mon Jun 29 2020 08:23 AM
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?
Posted By: glenns towing Re: Thermostatic spring - Mon Jun 29 2020 01:29 PM
Total opposite actually.
Posted By: tclederman Re: Thermostatic spring - Mon Jun 29 2020 01:37 PM
Pictures might help?
explanation/description : exhaust manifold heat control valve [chevy.oldcarmanualproject.com]
explanation continued : with another nice illustration [chevy.oldcarmanualproject.com]
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