1955 thunderbird exhaust manifold gasket Revision

[Martin P]

I am needing some advise to the revision that is possible for a 1955 thunderbird exhaust manifold where the replacement Gasket has the smaller center hole thus restricting the exhaust And heat over the center of the manifold. My mechanic is advising that this will not work as this will effect the heat necessary for the chock to operate properly, in other words the vacuum closing or opening when it is either hot or cold this effecting the performance of the carburetor and smooth operation of carbureto. Can anyone comment on this issue to advise as to what their experience has been with this modification? Seems odd that a fix is possible to prevent paint burn off and if this effects the operation then this revision would have been deemed ineffective

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[jack-in-sac]

I am needing some advise to the revision that is possible for a 1955 thunderbird exhaust manifold where the replacement Gasket has the smaller center hole thus restricting the exhaust And heat over the center of the manifold. My mechanic is advising that this will not work as this will effect the heat necessary for the chock to operate properly, in other words the vacuum closing or opening when it is either hot or cold this effecting the performance of the carburetor and smooth operation of carbureto. Can anyone comment on this issue to advise as to what their experience has been with this modification? Seems odd that a fix is possible to prevent paint burn off and if this effects the operation then this revision would have been deemed ineffective

I believe this is a repeat of a recent discussion.

 

[doug7740]

I am needing some advise to the revision that is possible for a 1955 thunderbird exhaust manifold where the replacement Gasket has the smaller center hole thus restricting the exhaust And heat over the center of the manifold. My mechanic is advising that this will not work as this will effect the heat necessary for the chock to operate properly, in other words the vacuum closing or opening when it is either hot or cold this effecting the performance of the carburetor and smooth operation of carbureto. Can anyone comment on this issue to advise as to what their experience has been with this modification? Seems odd that a fix is possible to prevent paint burn off and if this effects the operation then this revision would have been deemed ineffective

Your mechanic is incorrect by advising you that it will not work and that will effect the heat necessary for the chock to operate properly.

Manifold vacuum channeled through a passage in the choke control mechanism acts to draw the choke vacuum piston downward, thus exerting opening force upon the choke plates. As the engine continues to run, the vacuum acting on the choke vacuum piston draws filtered air from the carburetor through the heat tube in the intake manifold where the air is warmed by engine heat, and then through the thermostatic housing where the air warms the thermostatic spring, causing it to contract. This gradually decreases the tension of the thermostatic spring.

(See attached diagram and picture)

I purchased an intake manifold gasket set from CASCO, part number 9433. There is a smaller opening in the area where the exhaust gasses pass through intake manifold, thus preventing the paint burn off on the intake manifold. This smaller opening has had no effect what so ever on the operation of my automatic choke.

doug7740
1955 Thunderbird Blue

 

[Martin P]

Your mechanic is incorrect by advising you that it will not work and that will effect the heat necessary for the chock to operate properly.

Manifold vacuum channeled through a passage in the choke control mechanism acts to draw the choke vacuum piston downward, thus exerting opening force upon the choke plates. As the engine continues to run, the vacuum acting on the choke vacuum piston draws filtered air from the carburetor through the heat tube in the intake manifold where the air is warmed by engine heat, and then through the thermostatic housing where the air warms the thermostatic spring, causing it to contract. This gradually decreases the tension of the thermostatic spring.

(See attached diagram and picture)

I purchased an intake manifold gasket set from CASCO, part number 9433. There is a smaller opening in the area where the exhaust gasses pass through intake manifold, thus preventing the paint burn off on the intake manifold. This smaller opening has had no effect what so ever on the operation of my automatic choke.

doug7740
1955 Thunderbird Blue

 

[Martin P]

This is exactly what I needed to confirm, thank you for the detailed explanation. The mechanic has an overly confident attitude that it’s his way or nothing at all. I am about to yank the car right out of his garage!

 

[doug7740]

Installing an intake manifold gasket set with a smaller opening in the area where the exhaust gasses pass through intake manifold is a proven repair to prevent paint burn off on the intake manifold.

I think it might be time to find a new mechanic.

doug7740
1955 Thunderbird Blue