1957 Heater & vacuum lines routing

[Zoopie]

I added the heater control valve vacuum type on the engine block. I had assumed this was the standard for the '57, there does not appear a way to route the vacuum hose through the firewall. Other questions are, where does the vacuum hose attach to under the dash, workbook does not point that put? Does the hose connect to the vacuum thermostat valve or the vacuum water valve, and are these two valves connected together. Lastly, does this work commence from the engine bay or under the dash. All said and done, did I order the wrong part for the engine block. Thanks
cam

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[doug7740]

Below is an article written by Barry Thomas for the September/October EarlyBird magazine. The article explains the heater system on the early T-Birds and has a vacuum hose schematic that explains the vacuum hose routing.

 

[Zoopie]

That helps big time. That said, I still can't locate the hole in the fire wall for the vacuum line. There is a cable for the side vent coming out of that general area, if I'm looking at the fire wall from outside of the car, it's upper left. Is the cable miss routed?

Thanks for the response!!

 

[doug7740]

Attached is a picture of the heater box from The Thunderbird Restoration Details and Specification Manual. The vacuum hose for the heater valve enters through the firewall along with the heater motor wires.

doug7740
1955 Thunderbird Blue

 

[Pink T-Bird]

Resurrecting this thread as it seems most related to my issue -

I'm converting from the above mentioned CACSO mechanical manual valve to the original vacuum design while I had to replace the leaking heater core anyway....
There is a small port and a larger port on the NORS temperature regulating valve I purchansed. Which one is the vaccum source and which one is the vacuum to the engine valve? It looks like it wants to be the larger diameter on the control to the T on the vaccum source shared with the wiper motor? Nothing I have shows which port is which. I'd like to button it up and do not want to take apart the fragile original cardboard plenum again, not sure how much more manipulation it can take.
Separately since I was replacing all the 30+ year old radiator hoses too, I decided to proactively replace the thermostat as I believe it is also 30+ years old. I bought the NAPA #6. Now I cannot get a seal on the thermostat housing. First time it leaked at bottom dead center. Took it apart, re-cleaned, then sanded to bare metal, the mating surfaces got another new gasket, use a bit heavier amount of silicon sealant and reassembled. Now it leaks at the top just to the left of center. I don't know how many more correct thermostat gaskets my local NAPA can get. I've done scores of thermostat replacements in my life and never had this happen to me before inlcuding a 292 Y-block. Is there something with the #6 thermostat or peculiar to the 312?

Thanks,
Greg

 

[Ward 57]

If it's the larger opening thermostat there is a known issue of it interfering it has been known that the snorkel of the thermostat interferes and needs to be trimmed.
The vacuum is fed by the intake manifold and supplemented by the fuel pump to assist the wipers on acceleration. Shouldn't have anything to do with the plenum. No need to mess with it. The only large hose should go to the booster if it has power brakes. Time to put your plumbing hat on.

 

[jimntempe]

I couldn't figure out what a NAPA #6 was so I bought a high flow "Mr Gasket" thermostat. I had no problem with leaks. Maybe the #6 is slightly bigger outside flange diameter and interferes? ANother possibility is that you are putting the gasket on the thermostat housing first and then the thermostat on top of the gasket. There is a recess in the housing that the thermostat sits into and then the gasket goes on.

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[doug7740]

Resurrecting this thread as it seems most related to my issue -

I'm converting from the above mentioned CACSO mechanical manual valve to the original vacuum design while I had to replace the leaking heater core anyway....
There is a small port and a larger port on the NORS temperature regulating valve I purchansed. Which one is the vaccum source and which one is the vacuum to the engine valve? It looks like it wants to be the larger diameter on the control to the T on the vaccum source shared with the wiper motor? Nothing I have shows which port is which. I'd like to button it up and do not want to take apart the fragile original cardboard plenum again, not sure how much more manipulation it can take.

I don't believe it matters which port you connect the vacuum source to.

doug7740
1955 Thunderbird Blue

 

[biddle]

Found this online:

The NAPA #6 thermostat work with the 1955/56 intake manifolds and 1957 E models. The issue occurs on the 1957 intake manifolds

As the thermostat opens, it extends and contacts the extension pick-up tube for the vacuum-operated heater control valve.. This issue can be eliminated by removing the extension tube on the bottom of the heater control valve.

The extension is threaded into the valve and can be removed by turning it counterclockwise. Once removed the NAPA # 6 thermostat can open fully. Removal of the extension does not affect the operation of the heater control valve.

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[paul5456]

The actual number for the NAPA # 6 is THM6

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[Pink T-Bird]

The actual number for the NAPA # 6 is THM6

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When you get the box fromNAPA it just has a 6 in the part number field. Anyway I found my issue. The NAPA thermostat is right diameter for the 312 housing but due to the design of the flange it is too deep. There is a ridge on the flange that is larger diameter than the throat of the housing so it won’t slide in flush.


Moderator note- please read this post about 1957 models- Post in thread '1957 Heater & vacuum lines routing' https://forums.fordthunderbirdforum.com/threads/1957-heater-vacuum-lines-routing.9163/post-78707

 

[jimntempe]

When you get the box fromNAPA it just has a 6 in the part number field. Anyway I found my issue. The NAPA thermostat is right diameter for the 312 housing but due to the design of the flange it is too deep. There is a ridge on the flange that is larger diameter than the throat of the housing so it won’t slide in flush.

Just to cover all bases I'll ask this question.. Are you putting it in in the right direction? The capsule should be pointing back toward the back of the car so that it's in the hot water inside the intake manifold. You don't want it on the radiator hose side.

 

[biddle]

Just to cover all bases I'll ask this question.. Are you putting it in in the right direction? The capsule should be pointing back toward the back of the car so that it's in the hot water inside the intake manifold. You don't want it on the radiator hose side.

Folks read the post about using the NAPA thermostat on a 1957- https://forums.fordthunderbirdforum.com/threads/1957-heater-vacuum-lines-routing.9163/post-78707

 

[Rogvh]

The attached pic may show the entrance of the vacuum line at the heater box(on the engine side of the firewall) a little better. My blower wire is below the vacuum line as compared to the above pic. The routing then goes to the temperature regulating valve inside the heater box(on the inside of the firewall under the dash). As mentioned above the vacuum line continues on to the tee fitting.

 

[biddle]

@Rogvh I inserted your image as a full size using this message: