My exp valve was not going to fit with everything else that was new anyway, if it had fit I would have used it. I sold it on ebay to a guy with a Cuda who was very happy to get an original and correct valve. Otherwise I would have tried adjusting it just a little and see what happened.

So...what are you using instead?

As far as the valve goes, it can be swapped for the less elegant type with a single bulb that just gets attached to the evaporator outlet and insulated.

I looked real close at the original valve and the pressure is adjusted / calibrated by simply using an allen wrench inserted into the outlet. One would have to set up some sort of test set off car and, I assume, use compressed air or better yet dry nitrogen. The sensor bulbs temperature would need to be controlled during calibration, maybe immersed in water.

In the end the goal would just be to drop the pressure something like 4 or 5 psi., so maybe it would just need to be adjusted that many psi from point A to point B without getting too fancy. Perhaps some trial and error could result in a "rule of thumb" amount to turn the adjustment? Just so long as it does not end up too low and cause frost problems.

My exp valve was not going to fit with everything else that was new anyway, if it had fit I would have used it. I sold it on ebay to a guy with a Cuda who was very happy to get an original and correct valve. Otherwise I would have tried adjusting it just a little and see what happened.

There are two basic types of expansion valves, the externally equalized (which has the pressure sensing line that goes to the outlet of the evaporater, and the internal equlalized, which sensis the evap pressure on the inlet of the evap. The purpose of the expansion valve is to meter the refrigerant into the evaporator, to maintain a "almost flooded evap". it does this by comparing pressure and temp of the refrigerant. The externally sensed valve is better at controlling this, because it senses the presure and temp at essentially the same place in the system. The adjustment in the end of the valve is to adj the "superheat". It does not adj pressure. Every A/C evap needs a certain amount of superheat to allow the coldest evap possible, with out allowing liquid refrigerant to get back to the compressor.


Dan, as for the regulation about HP coutoff switches. I don't know where to look that up, maybe on the EPA website, about retrofits. It might be listed in the same place that says, any system retrofitted to a refrigerant that contain R-22, must use "barrier" style hoses. I learned this stuff going to different schools and training sessions, but that was maybe 15 years ago. I have been to numerous "schools", on A/C and refrigeration.
PS I am certified under part 608 and 609.

So if I wanted to get rid of the oem expansion valve with all of the associated capillary tubes to "clean things up" under the hood

1) find a way to plumb a 134a internal sensing exp valve into the the high pressure line at the firewall.

I wouldn't do this, if I were you. The OE expansion valve works very well, and...really, now, does its appearance bother you that much?
You could put in an H-style (block) valve if you really wanted to. They make them with threaded fittings. But it'd involve a lot of tube, fitting, and flange reworking, and for what real benefit? Again, I think you'll see a much larger, more cost-effective improvement in system performance by going in for some quality window tinting (I like the Llumar films; I've had 'em on the Lancer and the 164 for years and they've held up very well).

I'd also look at insulating the space between the headliner and the metal roof panel, and the next time you've occasion to pull up the carpet, improve the insulation there, too, and behind the back seat.