Installing Factory A/C in non-AC '74 Dart

[Three-nuts]

I have obtained the entire system, including dash and underhood wiring, and am hoping to be able to add A/C to my '74 Dart Custom.

Aside from replacing the receiver/drier, PAG oil instead of mineral, new green O-rings and possibly drilling a couple large holes in the firewall below the heater hose inlet...is there any reason this can't be done? My chief concern is getting the wiring right...I have to check to see if either of the brackets I have will mount the OEM compressor to a /6 (the system came from a V8 car, and the '71 /6 I installed a couple weeks ago apparently had a Sanden compressor).

I did read about replacing the condensor with a parallel-flow unit, and something about shielded hoses, but for the time being (assuming that none of the components have inherent leaks) I plan on installing all OEM & upgrading later as needed.

Based on what I've been reading, I'm bucking the trend here, but it's hot as balls and humid in Philadelphia between May and nearly November, and my wife plans on driving the car once my son gets through with destroying it...

 

[Arco440]

there is no reason this cant be done.
A couple of things to help
First keep all lines and ports closed with caps or tape.
after you change the oil flush system once all compotes are installed they self a/c flush kits.than once this is done add new oil to compressor.now hook up gauges and a good strong vacuum pump.You probably wont have access to a micron gauge so it's best to pull a vacuum as long as you can this can runs for days and can't hurt your system only help.Moister is your enemy!!!! the only other thing i would add is if you run a electric fan it must run in the on position any time the a/c is actively on.If your running stock /6 set up look a the fan blade and or if a factory /6 car with a/c I would run that set up.Also make sure your radiator is for a factory /6 A/c car or for a v 8 car. Also look at the water pump to and see if the factory specked a higher flow water pump,or even a different size
pulley as to help move more water .Just make sure your cooling system is up to snuff.

Hope this helps.
Arco

 

[Arco440]

P.S. I am kinda local and all so and hvac tech and i have a vacuum pump if you need one.
Arco

 

[jhdeval]

Three-nuts I can tell you I am running hoses for an underdash using a stock compressor on a slant six. I don't know how well my cooling will work but I would recommend an upgrade to a 6 or 7 blade fan and a shroud. Also your V8 bracket will not fit a slant six. The rear support bracket at very least is designed to mount against the driver side motor mount. If you look at my thread you can see some pictures I have taken asking about it. If you want I can take a few more to try and help you decide.

 

[Three-nuts]

Ja I read about the fan & shroud (the radiator is from an A/C car...it runs pretty cool at the moment on a 4-blade fan with no shroud). I wanted to be sure there isn't bracket hardware lying around in the piles I have acquired in the past three weeks before I plunk down more for the /6 brackets (fortunately they're around & available).

The mechanicals I will solve. I'm concerned about getting the electricals correct. I am prepared to change out the entire dash harness if necessary (the underhood wiring is pretty simple). Also, powering the door vacuum & hooking it up properly. Autozone will 'rent' the gauges & I intend to buy the cheap, compressor-powered vacuum pump from Harbour Freight (I have a very large compressor) if AZ doesn't rent that out.

Someone suggested changing out the orifice...I've never done that but assume it's upstream in the vicinity of the evaporator.

there is no reason this cant be done.
A couple of things to help
First keep all lines and ports closed with caps or tape...
Arco

Ahahahaaaa this stuff's been open to the atmosphere forever. I'll be vacuuming it for hours...

 

[Three-nuts]

OK, I’ve run into my first major problem with this install:
Hosing layout.

This is the configuration on the unit. The AC lines line up well with the existing opening for the heater core lines:

However, the AC heater core nipples require cutting a new oblong opening. Not only is there no punchout for this (not that I really thought that there would be one), but it runs over the stamping for the windshield wiper motor, which is offset from the firewall itself a good half inch.

I have been unable to find good photos of a ’74 Dart /6 engine compartment with factory AC, but the photos I have been able to see at do not appear to have this configuration.

Also: big fun drilling the case mounting holes with the motor in the car...looks like I'd have to make a template and do it from inside the passenger compartment.

This is looking less & less like a good idea.

(edit) wow, looks like new holes have to be cut for both sets of nipples, plus the fan motor mounts from the engine compartment (MUCH bigger hole), plus vacuum line hole...

 

[6pk2goDemon]

See if this pic helps U. It's from a 76 Swinger /6 factory AC car.....

 

[gunbunny]

Oh boy, your going to need to cut you blower motor hole larger also. there will also be 4 holes needed for the mounting studs and a hole for the evap drain as well as one for the little nipple under the blower motor. then, you need to make a brace for the front of the box. Obliviously you will need a new control head as well.
I speak from experience as I just finished mine up today. Now, I just gotta figure out the vacuum lines and charge it.

 

[Three-nuts]

6pk2goDemon: thanks for the photo.

And thanks to all who have posted.

I am selling the car for a variety of reasons, none are the fault of the car.

 

[dodge71demon]

I am also doing this on my 74 BUT I have my car tore down to the shell and I have the donor car.I was trying to figure out how to recut the holes needed so I just cut the firewall out of the donor car and used it as a template.It will be very difficult to get all the holes exact by measuring

 

[gunbunny]

Man, I wish that 2nd pic wasn't so blurry.