A/C Heater Box Modification?

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mopowers

mopowers

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This is probably a really stupid question, but I'm wondering if an AC heater box can be used for just a heater/defroster.

I pulled the heater box this weekend in my 68 Dart AC car thinking I'd get rid of it and patch the holes on the firewall. At first, I was going to cut the vent side off and modify it so I'd at least have a fresh air vent. Now that its out, I'm wondering if I could keep it pinned in heater mode and get rid of the A/C garbage that wouldn't be needed (evaporator, associated doors, etc).

Has anyone done this?
 
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I assume it will work. I have seen quite a few heater/AC boxes on here that have been stripped of their AC components. I removed all of the AC components from my car, sealed the AC vent off of the box, and screwed a plate into the firewall to cover the AC line holes. I think you just have to keep a working valve to turn the water flow on and off for the heater core. I kept the vacuum activated valve on my inner fender, but you could also just put on a manual valve in the heater hose line.
 
Why is a heater hose valve needed if non ac cars didn't have them? Excuse the ignorance. Is it bad to have hot water circulating through the heater core even if the fan isn't on?

I just got in from the garage. I cut the AC side of the box off and will patch it with sheet metal. Just left the fan and the lower vent with defrost outlet. Now I just have to rig up a way to open and close the defroster/lower heater vent door.

Another question- Where does the AC control panel source it's vacuum from to send to the vacuum actuated valves?
 
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I think (and I am no expert) without stopping the flow through the heater core, you will always have the box circulating heat. You may be able to come up with a way to close the outlets/vents, but the vacuum activated valve that controls water flow under the hood is also tied to the vacuum controls that control the movement of heater doors and block offs in the box.
 
Yeah I see what you're saying. I still may or may not reinstall the vacuum actuated valve on the heater hoses. I'm just tyring to unclutter the engine compartment.

Plus, with the blower motor off, and the internal heater box doors directing air away from blowing through the core, I don't believe running water through the core all the time will be a problem.

I'll post some pictures of the modifications as I progress.
 
Frankly it would have been better if Ma WOULD have stifled the coolant in a non-AC car. There is going to be a certain amount of heat radiation from a hot core, "not wanted" LOL on those hot days. Some of us used to put a manual valve out in the engine bay. This is great once the weather gets warm enough you don't need the heat
 
67Dart273 said:
Frankly it would have been better if Ma WOULD have stifled the coolant in a non-AC car. There is going to be a certain amount of heat radiation from a hot core, "not wanted" LOL on those hot days. Some of us used to put a manual valve out in the engine bay. This is great once the weather gets warm enough you don't need the heat
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Good point!
 
mopowers said:
Yeah I see what you're saying. I still may or may not reinstall the vacuum actuated valve on the heater hoses. I'm just tyring to unclutter the engine compartment.

Plus, with the blower motor off, and the internal heater box doors directing air away from blowing through the core, I don't believe running water through the core all the time will be a problem.

I'll post some pictures of the modifications as I progress.
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how is this process going ??


i have a 70 dart that was slant 6 A/C car but when did the -8swapipulled and chucked all the A/C stuff and have no clue how to get the heat working again. I only need it now and then and really only defrost for those early or late season morning or evening when frost is just starting to rear its ugly head.

I have had it working by pulling the rods under the dash to certain positions but with no vacuum or other connections they always settle back to the nonworking position.
 
I've pretty much finished the modification. I've got the A/C portion/blower plenum modified and the heater box rebuilt. I basically cut off the whole A/C side of the blower plenum eliminating the evaporator, thermo switch, and associated vacuum actuated door. At this point, everything is reinstalled and waiting for just a few odds and ends. I kept the heater hose valve after thinking about it for a bit. I also R&R'd the vacuum switch and other control so everything operates smoothly. What a pain in the *** that was. I'll let you know how everything works when I get the car going again.

Picture0903160825_1_zpsrxyczu66.jpg


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Picture0903160820_1_zpsnmx7mqud.jpg
 
Thanks.


I'm just gonna figure a way I can get it in the position to blow out the top dash because I only need defrost now and then.
 
1970-dart said:
Thanks.


I'm just gonna figure a way I can get it in the position to blow out the top dash because I only need defrost now and then.
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That would be a piece of cake. Just pin it to the defrost position and rig the switch to only power the fan when in the defrost mode. Bingo! Good luck.
 
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