Acauth 1, you're the AC guru, what do you think about this?Variable orifice (http://www.acsource.com/index.asp?PageAction=VIEWCATS&Category=273)

I think very little of them, they are more "hype" then they are function. I have used quite a few of these in the past on different vehicles and have noticed no difference between them and stock orifice tubes. In short, save your money for something you really want or need.

Thanks for the heads-up. I think I remember reading on the Internet about using an orifice with a smaller opening after R134A conversion. Supposedly improves low idle AC cooling. What ya think?

Not necessarily, it really depends on the vehicle. Your best bet would be to use the original white o'tube and adjust the pressure switch accordingly and verify the charge is accurate. And make certain you have a good fan clutch and shroud installed. I have done many g-body conversions and they work as well as they did with R12, especially elkys with the smaller passenger compartment. I have had to replace the white o'tube with a blue ford type in GM's due to the inlet tube on the evaporator being boogered up and the fact that the blue tube has two slightly larger o'rings for sealing instead of the one o;ring that the white tube has.
The difference between the two isn't that much, and I have experimented with both and the results have really been negligable.

What I did to some of my 5th gens and other GM rides was bypass the heatercore in the dead hot of the summer......man, that helps coolin alot..

Those blend boxes can get mighty hot with that heater core on the otherside of that flimsy lil door... I have noticed over 10 degrees difference on some systems I have bypassed..Brrrr

you have to cork the core so it won't rott out...or come up with something cool like I did on a Trans AM and keep it all intac but with "2" heater shut off/block off valves manually set

Does that sound too hillbilly???




aucath1 is right about those orfice tubes...junk/junk/junk

What I did to some of my 5th gens and other GM rides was bypass the heatercore in the dead hot of the summer......man, that helps coolin alot..

Those blend boxes can get mighty hot with that heater core on the otherside of that flimsy lil door... I have noticed over 10 degrees difference on some systems I have bypassed..Brrrr

you have to cork the core so it won't rott out...or come up with something cool like I did on a Trans AM and keep it all intac but with "2" heater shut off/block off valves manually set

Does that sound too hillbilly???




aucath1 is right about those orfice tubes...junk/junk/junk

Actually, if you have a good non leaking through heater control valve and vacuum to it in the cold position it will prevent flow through the heater core....that's its job!

ya, I know I know, but I like the hillbilly way

last summer when I was taking my cars to their new storage, I thought my face was going to melt off except in the one that I bypassed..that darn heat dissapates here in SC

Let me ask you something, was it the right thing to do by disconnecting all my A/C compressor wires on the cars I hardly ever drive until I am really ready to play with them.....I just don't want some clown burning me up or down when it comes to playing with my a/c switches, especially if all or most of the freon has leaked out.....and after you have stored a vehicle for a period of time is it true you problably should run the system at least 20 minutes to "allow the system to reseal iteslf" as it states in my GM restoration kit?????????

It depends on the year and make car we're speaking of here. Regardless, if is a later model car with a pressure cycling switch, and the system is out of refrigerant...it will not run the compresser if the controls are on, so damage isn't really possible. If it is low on charge, then the compresser will cycle rapidly on damage to the compresser clutch can occur.
If it is an older system without a pressure switch, then yes, you can cause damage to the compresser.

Running the system occasionally is a good idea to keep the compresser lubricated if nothing else. Most newer systems cycle the compresser anyway in the defrost mode.

As to theory on why the compressor cycles in defrost mode even in the hot setting...is it to use the evaporator in some way to remove moisture from the air or was my Daddy just pulling leg?????? even a ford will do that,,,,,why???? to me it is just a law of nature I have to deal with...
what year did Gm start putting low pressure switches in anyway????

As to theory on why the compressor cycles in defrost mode even in the hot setting...is it to use the evaporator in some way to remove moisture from the air or was my Daddy just pulling leg?????? even a ford will do that,,,,,why????

To help dehumidify the windshield.


what year did Gm start putting low pressure switches in anyway????

Again, it depends on which model we're discussing. A low pressure switch and pressure cycling switch are not the same thing.
GM introduced the CCOT (Compresser Cycling Orifice Tube,) systems during the late seventies.

Can you come over and do the A/C on the 70SS Chevelle I am doing????
I'll buy you a beer :-D

My god man, you are all over this site with good info...you want a job working for me??It might involve some Mopar though.........

Appreciate the offer, but I've got my hands full in Texas!

Thanks for all the good info Robert--all your first-hand experience is invaluable to us.

Thanks for all the good info Robert--all your first-hand experience is invaluable to us.

Anytime, that's why I'm here.