I am trying to restore the air conditioning system to my 1970 350. When Bubba removed it he basically ripped everything out and then painted the engine well black, wires, components, everything. According to the assembly manual the evaporator is located in the front of the car next to the condenser. However, Bubba left the evaporator in the car but it is located next to the blower fan.

My question is was there a change to the system in mid year 1970? Do 1971 and later cars have the evaporator located like mine is? Should I stop right now and forget the whole thing?

 

Evaporator in front of the car wouldn't do much good, but I could be wrong. Are you maybe thinking of the accumulator?

 

Could be, I'm not very educated on the air conditioning system, just yet. But the assembly manual showed nothing resembling what I have next to the blower fan.

The device I have next to the fan is a silver aluminum looking cylinder with an attachment on top. It looks like the device in all of my other cars that when the ac is on collects condensation on the outside and drips it all over my garage floor.

 

Post some pictures and I'm sure others will be able to help you.

 

Contact snowman, he just pulled his air cond out. He may sell it to you.

 

I hope that I can do this right. Uploading photos has always been a problem for my pea sized brain. Here goes!

 

That silver canister is the Receiver-Dryer.

 

That's the same as my 1974. Disconnected but intact.

 

OK, receiver-dryer. The assembly manual shows the receiver dryer attached next to the condenser. Does the 1971 or newer assembly manual show a change of position? Was the system installed on my 1970 a newer system with the change of position? Help!!!!

 

I don't see any difference from 1974.

http://img.photobucket.com/albums/v1...orator0001.jpg

 

Apocolips,

I am by no means an A/C expert however based on what I can see from the picture you posted, the system currently installed in your car isn't original or "correct" for your car. It appears that there is an orifice tube in the inlet of the open tube that goes into the bottom of the evaporator. You should be able to confirm that by grabbing the tab with a pair of needle nose pliers and pulling it out. If there is an orifice tube in there then that means that your system has been converted to a cycling clutch type system. Corvettes didn't move to the CCOT (Cycling Clutch Orifice Tube) system until the change to the R4 compressor (the shorter but larger diameter style of compressor). The system which was originally on your car used the long A6 compressor with a POA and expansion valve. some time after, but before the move to the R4 compressor, Corvettes went to the VIR (Valve In Receiver) system which combined the POA and reciever/drier into a single unit; that is the type of system shown in the AIM page that paul 74 posted.

If you decide to repair what is currently in the car, rather that going back to what is "correct" you may find that you will have a hard time finding an A/C shop that will work on it because what they will see in their parts catalogs for a 1970 Corvette won't match up to what they are seeing in your car.

Regards,

Jay

 

Thanks Jay. I know nothing about these systems. Was just trying to help.

 

I know that bubba put a new or different front clip in the past. The car had been wrecked. Do you think that he replaced the original blower/evaporator assembly with one from a newer car? What year did they change over to the newer system? If this is the case, I’ll have to rethink the whole thing. I found mounting brackets for the old style compressor in a junk yard. I really wanted to have A/C this summer. Any suggestions from anyone? Can the newer style system still work with my 1970 controls and wiring?

 

Oh, I almost forgot, thanks Pual74. The system that you showed is exactly like the one in my car.

 

Either system will work fine in your car with the controls on the console. Some prefer the older style system where the compressor runs all of the time and the POA and expansion valve maintain the "ideal" pressures in the system to maximize cooling. As you might guess this also uses more gasoline since the compressor is always running. Also, the older system has more "moving" parts (POA and expansion valve) so they can be more problematic to maintain. The newer style system maintain "correct" system pressures by cycling the compressor on and off and the orifice tube "meters" the refrigerant into the evaporator to maintain as close to ideal pressures as possible but it is more of an average pressure and these systems will never cool as well as the older style where the compressor runs all of the time. Also, with the cycling clutch system you will feel when the compressor cycles on and off, especially on the highway at a constant speed.

Regards,

Jay

 

Paul,

I suspect that if you take a close look at your system, you will see that your receive / drier can be taken apart to repair the POA valve and replace the desiccant in the drier. The receiver/drier in the picture that Apocolips posted is welded and doesn't contain anything but the desiccant. To service his part, he would simply buy a new part and replace it.

Regards,

Jay

 

Apocolips, you can cobble up your pieces that you have and make them function. Blower motor wiring and A/C vent/outlet controls will be for the 1970 system. 70 compressor can be used that way you can use the brackets you have. Compressor control may have to be be adapted.
The evaporator(pictured) in your car is out of a late 80's car. evaporator temp or freon expansion rate is controlled by a orifice tube. you can just see the end of it in the open tube in your picture.
Accumulator-silver can in your pic- is not a servicable part you will have to get a new one.
Here's the trouble there are several layouts of these, inlet and outlet ports are located in many different locations.
You're going to have trouble getting lines made with the right ends and bends.

Here's something alot of folks dont know. The evaporators on almost all GM vehicles are the same size, just the inlet & outlet ports are configured differently.
Your easiest and less hassle approach would be to purchase a evaporator for a 70 vette, purchase a POA eliminator kit. Purchase new lines for a SB 70 vette have it charged(I prefer R12) and be cool this summer

 

The internals of the A6 are much heavier that the R4 and the clutch on the A6 compressor was never designed to be cycled on and off that frequently so I suspect that using an A6 compressor in a cycling system would lead to more frequent A/C clutch failures.

Regards,

Jay

 

Thanks everyone. This whole idea of reinstalling the a/c is giving me a headache. I am disappointed however, about the wrong parts installed in my 1970. I have some head scratching to do before I spend any more money. It's going to be a long hot summer!!!

 

When I bought my '72 in 1988 the a/c compressor,brackets and hoses were given to me in a box. I live on the central coast in california so there are not too many days when you need air conditioning. But, I'm of the mindset now that if my car has an option in it, I want it to function. So, a few months ago I stared to rebuild my a/c system. For the amount of money I spent I know I could have gotten an aftermarket system but I wanted to maintain the stock look as much as possible. All of the parts are new. I got a hot rod air sanden 508 compressor $219.00(rear exit, polished) and fittings,approx. $50.00 from rjay's, parallel flow condenser kit $199.00(included condenser,nice brackets,hi/lo shutoff switch,drier and bracket, two hardlines) and compressor mount brackets($91.00) from vintage air. I still had the original poa valve,expansion valve and evaporator but since I didn't know the history of these parts I decided to go with new stuff. The evaporator was $150.00 from the partsladi. POA valve(adjusted for 134) was $99.95,expansion valve $24.95 from texaserick. a/c wire harness wire harness $109.00 from the last detail. New center vents and side vent ***** $60.00 from corvette pacifica. 4 ft. of #6 barrier hose $5.36, #8 $6.56, #10 $8.16 from arizona mobile air. Also had to buy a step down fitting for the POA valve(#12 fitting to #10 hose) $15.00,found it at carquest. Idle up solenoid $22.00 from autozone(although when I turn on the a/c the idle speed really doesn't drop all that much). I cut the hoses to length myself and assembled the fittings in the correct orientation to the bend of the hoses then took them down to a local shop that had a beadlock fitting tool and had the fittings crimped onto the hoses, $10.00. Assembled everything, took the car down to the a/c shop and had it charged up. I felt pretty good when the a/c guy said there was no leaks and that I had down a great job of putting everything together. Like I said, it doesn't get too hot around here but in my garage when it's 75 degrees outside, the center vent temp get down to 36 degrees on low fan speed. We'll have to see how performs when I go visit my family in the central valley where I grew up. HOT!