Technical Salvage Yard Air Conditioning ? ? ?

Following years of tradition, it occurs to me that I can save a bunch of $$ by taking a later model car's entire air conditioning system and adapting it to my sectioned '50 Ford club coupe powered by SBC....saves money and gives me something to do..(or at least, think about). Labor is not really an issue, because I do my own work.

The questions I pose to all HAMBers are:

Is this a good idea?? Why or why not??
Which donar car would be the best to give up the parts??

What I would like to hear from any HAMBer is opinion based on experience. If you have been through this drill, I'd like to find out how successful it was.

Thanks in advance.

 

Go to a you pull-it junkyard. Suburban and conversion vans. The back A/C unit up in the rear roof area has a compact A/C evaporator, blower motor and heater core. $12


Ago

 

Make sure you find one that hasn't been opened up they're most likely contaminated.

 

Used to be you could find old aftermarket under dash AC units in junkyards. They're not so common these days.

The modern factory HVAC systems are designed to fit the car, it would be tough to find a modern car with the same shape firewall and dash as a 50 ford. And all that plastic and electronics crap is rather ugly.

 

x 2 on the conversion vans. I've got the rear unit from a ford van for my 34 PU. it's practically indistinguisable from the small aftermarket units. I almost sold it at a swap meet a few years back and then I realized it was a heat and air unit and pulled it off the table. SBC should be easy to find stock bracketry for too. It's not SBC, but I have buddy who took my dad's serpantine system from a 302 that was getting a frontrunner kit in a 35 ford and used it in a 70 ford PU with no problems. I'm all for junkyard adaptation.

 

I found a old Frigidaire hang unit that was a aftermarket piece in a 1968 Ford Galaxie and used it in a 40 Ford sedan,I didn't use the drier or the huge compressor but for 20 bucks it fit across the bottom of the dash like it was made for it. HRP

 

Thanks for the quick responses.
First....I am putting a '54 Ford dash in the shoebox and it is currently "on the bench"...so adapting an evaporator/squirrel cage to the inside of the firewall should be do-able while the dash is out of the car...and
Second...I have a fellow that is parting out a '94 Suburban and is willing to separate all HVAC parts for $100. Nothing has been disturbed, according to him. (I have not looked at it.)
Third...I have ordered the Haynes Techbook on automotive air conditioning so I will know a bit more than now.

Keep the opinions and experiences coming!!

 

Thought about looking for/using a small car / foreign car system complete for under the dash of my 49 Dodge truck and learned the same lesson as the guy above... Most of the factory HVAC units are specifically designed around the contours of the car's dash, gauges, radio, satnav, etc. I spent an afternoon in a U-wrench-it looking up under dashboards or poking around in dashboards that had already been disassembled and couldn't find anything that even looked close to fitting properly. Especially since I wanted working defrosters, etc. because I want to drive this thing on cold/damp/humid days and defrosters and A/C are a must around here. Since my truck is using a 1995 Dodge Dakota chassis and drivetrain, I'm finding that it's easier to just adapt that stuff and modify/piece it together to fit under the dash of the 49, and all of the hoses, fittings, etc. will fit like they did when i took the Dakota apart. I did have to relocate the condenser to under the truck's bed (and had new/longer hoses fabricated) and mounted an electric fan on it because the grille area on the truck was too tall & narrow for the Dakota condenser.
I couldn't find any of the rear units from conversion vans or minivans in my local salvage yards, so I'm no help there.

 

I have used the bare evap unit and built a box around it and a remote mounted blower. Flex ducts to the dash outlets. Also the big Grand Wagoneers of the 80's and older have an under dash air unit that will mount under many older dashes with a straight bottom edge. It has all the controls and outlets already mounted. The rear units in the Mopar mini vans of the 90's mount on the side to the rear of the drivers seat and should fit in the trunk under the rear window of your shoebox and run ducts forward. Good luck.
Bob

 

I think what ever system used it would be a good idea to use a new expansion valve and receiver dryer. Done many of these type adaptions over the years and the one most frequent problem has been expansion valves not working properly. Some people will say either it works or it doesn't but I have found many times they will move only slightly and give a low low side reading and a low high side reading or even make the low side go into a vacuum.

 

http://www.hotrodders.com/forum/junk-yard-c-system-200848-2.html

Here is an article with some options.

 

I second the early Wagoneer under dash unit. I've installed a few of them and they fit the flat bottom of many dashes perfectly, and all the controls are integral. I'll ocasionally have to cut the left end duct off and hang it at the left "A" piller and feed it with tubing depending on the width of the recieving vehicle. The 80's and early 90's radial compressors fit the SBC nicely.

 

Make sure the system you get is compatible with today's "modern" refrigerants (R-134a, R-409a, etc). Pretty damn hard to find someone to charge an old system with Freon or R12 these days. Hoses, filters, and compressors may have to be changed to accommodate the new refrigerants.

 

Most systems designed for R-12 can work on R-134a. The exact specs may not be perfect, but it will work fine. Biggest mismatch is that R-134a requires a more efficient condenser than the old tube and fin R-12 style for maximum performance. Just make sure to use oil that is compatible with the R-134a or whatever refrigerant you are using. Mineral oil as used in R-12 systems is not dissolved by R-1234a. So just flush it it out and refill with POE oil for R-134a. You probably need to make new hoses for the different vehicle, so the new hoses will be barrier style hose. Although many use old hoses from an R-12 system without problems, it theoretically can leak a very small amount. Always use a new drier when the system is put back together.

 

I've used some aftermarket Freon replacements when charging older vehicles with good success. They aren't supposed to leak through an R12 system like R134a is supposed to do.

I've also put R-22 in an R-12 system, in a pinch, and it worked fine, but it's not commonly used in cars as it's more poisonous when set aflame (if I recall correctly.) I soon replaced it with an R-12 substitute called PermaCool (EDIT: that's not the right name. I'll have to look it up.) which worked as well.

I don't like the huge drier on the old GM systems, but haven't started looking for a donor AC yet. I'm considering a split system with tiny GM backseat units now (thanks to member AGO) in my Plymouth.

I have always intended to make my own boxes, to fit whatever flappers and vents I need under the dash, but I'm also considering a hard headliner with A/C vents through the headliner. This would mean a trunk mounted evap/fan, and defrosters shooting down from above the windshield.

I guess I'd need long Freon tubes or hoses, which need insulation (?) and I'm wondering which the GM backseat units use? I have a tubing bender and flare tools, so I was hoping to scavenge as much as possible and just have short custom hoses crimped.

 

The Suburbans just had bare aluminum tubes running to the rear unit. teed off from the front system.

 

Or you could go "Ford in a Ford" like I did here: http://www.jalopyjournal.com/forum/media/albums/302-with-mustang-a-c.34689/ It is all 1965 Mustang parts converted to 134a blows 40 degree air at 106 outside temps. Too bad you have that "foreign" engine under the hood

 

Hey Mexico isn't foreign. It's the 51st state once they all move here and vote it into the union.

 

Russ,check out "your conversations" got a deal for Ya.

 

Try R414b. It's a perfect R12 replacement. No need to change or purge anything. It's made by Whirlpool and is called, "Hot Shot." It's around $20.00 per can. Read the directions - they are easy but important if you want it to work right.

 

Guys around here use one out of a Honda, I am not sure which one.

 

I pht an after market one in my 69 Roadrunner and it was a prett simple system, that bei.g said, if you found all of the pieces it would be real doable. But by the time its all said and done it could be even money for a kit. I know the classic air heat/ac unit only blew air out the vents, not on the floor on your feet where you would expect it. On my 61 Olds 394 i just got done with the compressor bracket and found a new sanden 508 for 80.00 on the net. I have stock ac vents but will look around and see whats out there before buying a system. Mainly like was mentioned before is you want uncontaminated parts. I post if i find anything worthwhile because Im at that point witb my car.

 

Try to cut the firewall section that the a/c mounts to and graft that into your vehicle to simplify the install.

 

An idea I had, nothing like even vaguely thought through, was not to cool the interior air but only the roof sheetmetal of a car. Personally I dislike the sense of disconnectedness that A/C brings and I consequently don't own an air-conditioned car. At the same time I don't do well with heat. I've noticed that a huge part of my discomfort on a really hot day, driving with several windows open, comes from radiant heat off the headliner.

My thinking was, attach (solder?) small-diameter tubing to the underside of the roof panel to turn the entire panel into an evaporator. It'd be important to get conduction from the panel to the tubes to be as effective as possible. I'd add some nominal thermal insulation on top of the headliner. Condensation on the panel might be tricky to sort out.

Make of it what you will ...

 

Lets hear some more info on R-414b, sounds like a good replacement. What I don't like about some of the aftermarket A/C is no provision for fresh air. Sometimes you just need ventilation. My 32 has no A/C, but with a working cowl vent, fold out windshield, and roll down back window I get plenty of air when moving.


Ago

 

R414b (known as Hotshot) is a blended refrigerant of R-22, R-124, R142b, and R-600 (isobutane). The isobutane is what gives it the ability use for mineral oil based systems. The blend has similar pressure-temperature curve to R-12. R-414b is also not exactly commercially available like R-134a for the casual do-it-yourselfer.

The main problem is if you have a system that leaks, it does not leak at the same blend ratio as originally put in. So how do you know exactly what to top off with? Auto A/C systems are never leak free. It is just a lot easier to flush the system and use POE (aka ester oil) and R-134a.

 

A quick google search

"A blend of R-22, R-124 and R-142b with hydrocarbon R-600a (isobutane) added to improve mineral oil miscibility. This blend can be used to retrofit R-12 automotive air conditioning systems as well as stationary refrigeration systems. The pressure and system capacity match R-12 in 45F to 50F evaporators, and the discharge pressure in hot condensers is only 5 to 10 psi higher than R-12 (a benefit in automotove AC and warmer refrigeration environments). The temperature glide runs about 13F in the evaporator. The addition of isobutane to this blend significantly improves mineral oil compatibility, particularly for high viscosity oils used in auto AC."

You WILL still need to purge or evacuate ANY refrigeration system that has been opened.

 

Vintage Air sells an under dash hang on unit for $299. Almost doesn't pay to mess with junk yard stuff.

 

(1) It is harder to find than R134a. However, It is available to anyone who walks into their local appliance parts store. You happen to have at least two such places, that I know of, that sells it. They are near the intersection of Hwy 25 and Hwy 40.

(2) You are theoretically correct, however, in practice, I just add it to my car until it starts blowing cold air again. Then I wait for the temp. to stabilize (stop dropping), then add a little more. Wait. Add. Wait. Add ...until the temperature won't get any colder. I know that's not very scientific but it sure makes the air blow cold. You can mix it with R12. I will admit I am not getting the exactly correct blend ratio but it sure feels good in this Texas heat. Perhaps an engineer would feel 3 to 4% less comfortable if he rode in my car. In my opinion, it's easier than converting it to R134a if all you need is a top-off.

 

Especially when you consider the time to pull it and the time to engineer (rig) everything to fit.