1959 El Camino factory a/c upgrade

Marconidevice on Tue November 19, 2013 3:02 PM

Year: 1959
Make: chevy
Model: el Camino
Engine Size: 348
Refrigerant Type: r134a

Hello All,
I'm new to the forum and I need some help with my install.

I have a 59 Chevy El Camino that I've been restoring for quite a long time.

I need to make a choice on what I'm going to do for my A/C system.

The car has a 348 engine, and I've just finished rebuilding an A6 compressor for it.

I have a complete factory a/c system (in dash) from a parts car I had.

I also have a complete under dash GM Cool pack unit that was originally dealer installed in the car.

I would like to use the factory in-dash a/c but with a few changes so I need some opinions here because I'm going to need to cut the firewall pretty soon so I can move forward with paint work.

The factory in-dash unit used an A-5 compressor, a hot gas valve, tx valve and a high side dryer, the original condenser was steel serpentine.

My idea is to not use the hot gas valve and to cycle the compressor with an adjustable capillary tube thermostat with the capillary tube inserted into the evap. just like Ford and Chrysler and AMC would have done in the 60's. The temp cable would attach to the capillary tube switch to vary temp instead of the hot gas valve.

I would use a new replacement aluminum condenser core because of the odd shape of the radiator opening.

R134A would be used.

I will need to tig shut one of the outlets on the top of the evap. because it went back to the hot gas valve. (the top evap. hoses were crimped directly to the core originally, fittings were not used). I also have the option of adding a service port here and using a TX valve with an external equalizer tube as this would be the place to connect it.

My big question is about the TX valve. The replacement TX valve is listed as 1.5tons, with a superheat value of 10.5 I'd like to know if this would be appropriate for R134A or do I need a tx valve with a different superheat value?

The original Chevy service manual does not give any specifications on the original R12 TX valve so I'm not sure if the replacement valves are already compensated for R134A or not.

I've looked at 59-60 Oldsmobile service manuals, same factory a/c system except the doors are vacuum controlled and mine are cable controlled, Oldsmobile gives a Superheat value of 6 for the TX valve.

I would like to use the factory in dash air if at all possible. Cool-pack would be the next on the list but will have the same question on the tx valve in it.

I've considered a Vintage Air conversion since I work for a company that is a vintage air dealer, but Vintage air warns against using an A6 with any of their systems stating it has too much displacement. the A6 is staying.

Any help to point me in the right direction is appreciated. I can post pictures but not sure how to attach them on this forum.

I have a lot of automotive a/c experience, have crimping tools, vacuum pump, gauges etc.

Thanks!

Mark

Dougflas on Tue November 19, 2013 5:24 PM

Those compressors were not designed to cycle. The clutch area is not large enough for cycling. Truthfully, I would put a Vintage Air kit in if it were mine.

Marconidevice on Tue November 19, 2013 5:46 PM

GM used the A6 on millions of CCOT cars with cycling systems from 1977 to around 1982. was used a little while longer with cycling systems in trucks so I don't understand why you would say that.
I had an 80 Malibu with an A6 and a cycling system as well as a 87 Chevy truck with an A6 and a cycling system and they both worked fantastic and lasted until the cars were dead.
This car is more of a restoration with a complete factory tri-power set up on it etc. I want the look of the A6 under the hood. I will not put a sanden on this car as it looks way out of place on a restoration.
I know I tend to ramble on but my main question is how to figure out the correct TX valve if I do this.

I was originally open to the Vintage system and using the original outlets etc but vintage says that the A6 has too much displacement, 13 vs about 8 for a Sanden, they say it won't work well with their systems unless I can put a really oversized condenser in, and there is just not room for one.

mk378 on Wed November 20, 2013 9:07 AM

The same TXVs are typically used for either refrigerant. The difference in pressure-temperature characteristics at evaporator conditions is small enough to consider as the same.

Within reason there's no such thing as "too much compressor". Larger displacement helps at idle and low rpm. You can look at pulley ratios to slow the compressor down since of course displacement times rpm determines the output of a compressor. All 134a systems should have a high pressure switch to stop the compressor before something blows if for whatever reason the condenser can't keep up.

Systems that cycle on evaporator temperature usually use a fixed temperature and reheat the air through the heater core when the driver sets the dash control for less than full cold air. This helps to dehumidify the air. Cycling the evaporator at a high temperature can lead to uncomfortable humid air.

Marconidevice on Wed November 20, 2013 11:38 AM

Ok, I was concerned with the having liquid at the top outlet of the evap if the tx was wrong. You make a very good point about the reheated air, as this may be a problem as the heater is completely segregated as it's own system and does not connect to the a/c system in any way other than the air intake at the cowl.
This is what Vintage says about using an A6 with their systems: " We only recommend using it in a very large sedan with a high evap. capacity or dual evap's. and a minimum of a 400 square inch double row 5/16" copper and aluminum fin condenser.
this is what the replacement condenser looks like for my car - http://www.ebay.com/itm/59-60-Chevy-Impala-Condenser-a-c-AC-NEW-Car-air-1959-1960-Classic-/230776157487?pt=Motors_Car_Truck_Parts_Accessories&hash=item35bb54b52f&vxp=mtr
the radiator opening is oddly shaped hence the extra parts added to the bottom of the condenser.
I guess I'll go the vintage air route and hope for the best.
Thanks for your help mk378

moparmaniac73 on Wed February 26, 2014 9:44 PM

what a beautiful rig ..the el camino was and will always be the number one ute that was ever made in my books . i would love to see pics of your truck YES it is a truck in my books i had to say it . I am stuck on the fence with my charger leave it all original power robbing huge compressor or go with something that when you hit the A/C button the engine does or not almost conk out ... unless your Camino had a throttle stepper motor so when a c is turned on the idle is is turned up ...in 59 um maybe ...NOT ... RESTORE THEM DON'T SCRAP THEM ....

northernbeach on Mon March 03, 2014 4:26 AM

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