How does the Manifold Valve Body Flapper works??

[Guest Unikito]

I have a 1939 Buick Roadmaster which I am restoring. The valve body has a flapper inside. On the outside, on one side of the valve body,there is a thermostatic coil. On the other side there is a metal weight. No spring there but it appears there should be one. When you turn the weight until it stops, the flapper closes 90%. When I move the weight the other way, the flapper closes 100%.

These are my questions:

1) when the engine is cold, should the flapper be closed?

2) when the engine is hot, where should the flapper be positioned?

THe problem I have is that I do not know if I got to put a spring.Also how to put the thermostatic coil correctly, in order for the the flapper to work properly.

Any help will be greatly appreciated.

Thanks

(Pics attached)

Edited August 1, 2010 by Unikito
Adding a picture (see edit history)

[Guest Bob Call]

When the engine is cold the flapper inside should be closed. As the engine warms up the therostatic coil spring expands and opens the flapper. The weight is to hold the flapper open after the engine warms up. Maybe someone with a shop manual can tell you how the spring should be installed and tested.

[Ben Bruce aka First Born]

Unikito, you are fortunate the damper is free!! I still have not been able to free up the one on my '50.

Bob is correct. But i believe there was a small spring on the weight side to keep the whole assembly from ratteling. No real problem if not there.

The purpose of this "damper " is to direct some of the exaust through a channel to speed the heating of the carb when cold. As the engine comes to normal temp, it opens completly.

If you have not done so, please "come on dowm : to the Buick forums below and hang out eith us.

Good luck

Ben

[Larry Schramm]

One product that you might try to free up the valve is GM Heat Valve Lubricant....if they still make it. It was made specifically for this application.

[Vila]

GM Heat Valve Lubricant is still available at:

Heat Valve Lubricant

I purchased some last week.

Visit my website at: Bob's Vintage Cars

Bob

1933 Chevrolet

1984 BMW 633 CSi

1962 Triumph TR4

[Guest Unikito]

Thank you everyone, I will give it a shot. SOmeone was kind to provide me with some copies of the manual referring to the mechanism you both describe. Thanks,

[Guest De Soto Frank]

Also, the pressure of the exhaust gasses tend to force the valve open.

The spring holds the valve closed, even against exhaust pressure when the engine is cold.

[Guest]

Interesting that on Pontiac V-8's that manifold heat control valve was eliminated by the late 60's. The place where they are machined is still there on newer manifolds but thank goodness they are gone. They probably were eliminated because of the problem Unikito is having and there is enough heat still going back and forth between heads. I've run Pontiac's and Olds with the both heads blocked off with never any warm up problems. It also keeps the engine paint from burning off the heat riser portion of the intake manifold. The major benefit is depending on type of engine is about a 15-20 HP gain.

Don