A/C in a 51 Chevy

I know that alot of you guys dont like air conditioning in old cars, but I got my wife a 1 year old and a 4 year old that I want to be comfortable when we take the car out.

I got this AC unit from a buddy. He said that it is supposed to be ready for R134. I checked the fan and it works good.

I have a couple questions:

1. There are fittings on both sides. I am assuming that the threaded fittings are for AC and the capped off copper pipes are for heat.

2. There is a bit of reddish colored oil in the side with the threaded fittings. I am assuming this is the ester oil for the compressor. How do I know if its for R12 or R134.

3. Whats the best way to mound this in a 51 Chevy. There isn't a lot of room under the dash so I was thinking about mounting it under the hood with just the outlet ports coming thru the firewall. If I do this I will probably need to plumb in some ducting so the fans aren't sucking hot air from the engine compartment.

Thoughts? Ideas?

 

Unit usually mounts to underside of dash with 'L' shaped brackets with only hoses going through firewall.

Chances are you'll need new fittings in engine bay, hoes, dryer, condensor; possibly a new expansion valve and compressor. I believe some fittings for R12 and 134a (service port) are different. I'd suggest you speak to Vintage Air or similar, might be more practical or economical buying a complete new 'Old' style kit? Do you have the face plate with louvres and fan switch?

 

It wont work under the hood. Needs to go under the dash. It will work on R-12 or R-134. It will need a good flushing and you would want to do a real good cleaning of the expansion valve since this system has been setting open.
Do yourself a favor and buy a under dash hanger system. It will put out more A/C than what you have and you can still keep your stock heater.
http://www.vintageair.com/catalog11/pg50wc.pdf

 

Thanks for the input. My car doesnt have the stock heater. The previious owner took it out. I will have to see how much a new kit costs. I was planning on using mostly used parts with the exception of the drier, and maybe hoses.

At this point I only have this unit, and its wiring harness. I may have an old Volvo fan switch somewhere too.

 

This is one system in the car that I would highly recommend using all new parts. If one part has issues, it can effect the whole system.

 

I am a hvac tech, mind you for homes not auto, but I would guess that the txv (expansion valve) is specific for one type of refrigerant. It would be wise to try to find numbers on the txv and do some searching to find what type of refrigerant it was designed for. Pressure testing the coil with nitrogen would be the first thing to do, this will tell you if it has a leak and will save you a ton of wasted time, the last thing you want to do is get it all fabbed up and installed to find it leaks all the refrigerant out.

 

It should work with 134a, the red oil is probably dye that was added or in the refrigerant when it was charged, although R-12 dye is red. You're going to need whatever cable setup to change from heat to a/c on that unit also and a heater control valve of some sort.

 

From the looks of this setup there is no provision to go from hot to cold. I assume that it wants the heater valve to make that change.

From what I can see its just a heater core and an evaporator with a fan behind them. My plan was to have a cable or rod activated heater valve, a toggle switch to engage the compressor, and a rotary switch for fan speed control.

Doing a pressure test seems like a great idea. Does it have to be nitrogen? Or can I just use my shop compressor to test it? How many PSI?

 

unless he gave you all the parts it maybe easier just to get an underdash a/c kit at a swapmeet. the evaporator(what the pic shows) runs about $175 to $225 depending on the look and the style of the ducts. just added a underdash to my 59 chevy and it makes a huge difference on those 95 degree days with 100% humidity

 

I put in lots of Ac systems in older cars, I guess I work for a lot of Gold Chainers, and I like AC myself.
Can't see the inlets of the AC fittings but IF they are for an O ring type fitting, instead of a flare fitting, most likely the unit is for R-134. And yes, it is important with that type of expansion valve, to be sized correctly, though it will work, less efficently, if it is an R-12 unit.
You can buy separate fittings, at a better cost than Vintage, from Doc's Blocks, on the web. You can do them in rubber (barrier hose!!!!), or buy alum. hard line, and solder fittings, for a cleaner look, Doc's has both, and even the right solder to put them together (it's easy, too). You will need rubber from the compressor, to the firewall/wheelwell, for vibration dampening. Once you get all the hoses and fittings set up, an auto AC place will crimp them for you for a nominal charge. Be sure to mark the fittings to the hose, if they need to be "clocked" in a certain position.
Other than that, a fan switch, heat control switch, condensor, dryer, and a safety switch, binary or trinary, is all you need. Again, any auto AC place will have them, or go online to Southern Air, or any place that carries Vintage, to get the parts. Lots of webisites out there to give you diagrams of hose routing and part placement to help you lay it all out.

 

Cool. Thanks for the info guys!