Automotive Air Conditioning Information Forum

I have an '71 Plymouth Scamp that I have done a 2000 5.9 magnum EFI swap into using a '94 Dakota V8 harness and '94 Ram 5.9 computer. Now I'm trying to come up with a working A/C system and have some questions about how the two systems are routed. I'm definately not an A/C expert and won't know alot of the abbreviations and terms you guys may use, so don't hold that against me!

What I plan on using are the '71 style Evap core, expansion valve and condensor with the '94 compressor and dryer, then having hoses made. When looking at the routing of the two systems, I discovered a difference, and this is where the question comes in.

The '71 system goes: compressor -- condensor -- dryer-- expansion valve -- evap core -- back to compressor.
The '94 system goes: compressor -- condensor -- expansion valve -- evap core -- dryer -- back to compressor.

My question is: Does it matter where the dryer is in the system?

Wll, doing some research has shown me that both systems do not have a drier. The drier is used on the high side of sytems that use an expansion valve(what I planned on using) and systems with orifice tubes use an accumulator on the low side(like the '94 Dakota) So I either need to remove the expansion valve and use an orifice tube/accumulator or keep the expansion valve and get a drier. Since my underhood A/C wiring is the '94 setup, I think I may re-think my hoses(haven't been made yet) and put the orifice tube back into the setup and remove the expansion valve.

You would use basically the same wiring for either setup. The expansion valve system cycles the compressor based on a temperature sensor on the evaporator. The orifice tube system (aka "CCOT" -- Cycling Compressor / Orifice Tube) cycles using a pressure switch on the accumulator. Either system should also be fitted with a high pressure cutout switch on the high side to reduce the chance of damaging the compressor or blowing a hose under abnormal conditions.

Generally the TXV system is preferred, it offers a little better efficiency and is less critical of the exact charge amount. CCOTs were introduced in the 1980s by the US big 3 to reduce manufacturing costs.

Both receivers (used on the high side) and accumulators (used on the low side of a CCOT system) contain a desiccant material in a bag at the bottom of the tank to adsorb any small amounts of water and keep the refrigerant dry.