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1966 Olds Toronado A/C

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  • #61
    Long thread THANKS CB-89! Another couple off the wall things already may have been said? This car was intentional to stage release of 1st FWD Eldorado in '67. All those would have "Climate Control" I think lowest interior temp request ~65F? Front and rear well mixed may have ducts to rear if so were on floor?

    152a should read about like R-12 shown in charts already posted. That's lower pressures and higher caloric value than R134a so I'm told.

    BTW - a 10oz duster can from Harbor Freight last visit said in English it was 152a! Yes would need a side tap now to use that myself for remaining R-12 cans don't know what to trust with hockey can taps had one blow up - damn it! I'll just waste a duster can found elsewhere (only 8oz)
    see if the side tap seals well was costly will do tiny cans of just oil probably illegal now?

    If they are again going to bring up flammability of 134a think hard it's up like at 450F or something. Cars use gasoline too within a foot of A/C parts so I give up, YOU CAN'T FIX STUPID OUT THERE!

    MetroWest, Boston


    • #62
      There is a big difference between gasoline and propane. If you get a gasoline leak, most will stay in liquid form, while all of the propane will immediately be vapor. As we know, it increases in volume like 100x in the phase change from liquid to vapor. Liquid doesn't burn, it must be in vapor form to burn, liquid gasoline is always giving off some vapor, so a match held over a liquid pool will ignite the vapor, and the heat will release more vapor, but propane will be vapor from the get-go and all of it will go up at once.
      Yes, most cars carry a fair bit of gasoline, but in a form that is not flammable. It is why in tank electric fuel pumps are possible.
      A pound of gasoline in the cab vs a pound of propane, one will burn the other detonate. Gasoline is run outside of the cabin, and never inside.
      R134a isn't very flammable, R 1234yf and R152a are both slightly more flammable than R134a. R290 is far more flammable than any of the others.
      Last edited by Cornbinder89; 2 weeks ago.


      • #63
        This was all a done deal with R-12 if not the power grab by Dupont to make $ if duped (easily I hear) never proven to harm a thing, didn't leak easily could use heavy parts to transfer heat so good to be true let's outlaw it? Not flammable by anything realistic. Move on this full blown antique now is cool IMO worth what it takes.

        Carry on I expect to hear this will be all done and if not also a perfect body or other issues made into a fine car,
        MetroWest, Boston


        • #64

          I don't understand is why the POA set point with compressed air matters. I was under the impression that it was a way to approximate what the low end pressure was going to be once the system was operational. Air has different physical properties than a proper refrigerant, and the flow rates and pressures being pumped into the POA valve are going to be different too, never mind that my bench test takes place at room temperature, whereas a working POA runs much cooler, which will affect the density of the refrigerant and the viscosity of the oil that is suspended. To me this is a very dissimilar comparison.

          If my theory has some validity, I would be tempted to lower the POA setting a bit and try to get closer to 23PSI in the low side while the system is operational... And see what happens.

          I think it's clear that condenser performance has a big effect in my case, as vehicle speed has a noticeable influence on vent temperature. I was able to force more air from the mechanical fan to go through the condenser and that greatly improved vent temperatures while at a stop, but it's still coldest when the vehicle is moving at a high speed. How much extra efficiency can one expect from a modern parallel condenser vs a 55 year old tube and fin one?

          I am doggedly trying to avoid using R12 (which has become cheaper than it was 15 years ago), wanting to find a working solution with something that is readily available and hopefully will be made for many years.

          As to why R152A was never used widely as a refrigerant, I'm not sure. There is some flammability (and since cars already have plenty of flammable fluids and solids, I'm not particularly concerned about this), but it wouldn't surprise me that a large mega-corporation pulled some regulatory strings in DC to make sure that their product became the preferred refrigerant. Surely these kinds of things have never happened before.



          • #65
            Originally posted by Tom Greenleaf View Post
            Long thread THANKS CB-89! Another couple off the wall things already may have been said? This car was intentional to stage release of 1st FWD Eldorado in '67. All those would have "Climate Control" I think lowest interior temp request ~65F? Front and rear well mixed may have ducts to rear if so were on floor?
            Yes, the Toronado and Eldorado of that era came with an automated HVAC system, called the Confortron. Mine is not entirely operational. I use a mechanical vacuum regulator to control the Power Servo, which is the brain (or actually the executive branch) of the system and gives me full heat to full A/C, with anything in between (including controlling doors and fan speeds), given a variable vacuum signal. Quite an ingenious system.


            • #66
              IDK why 152a wasn't on the scene long ago? On vacuum source? Make sure you have or get one a check valve and vacuum storage tank as engine vacuum varies up to zero flooring it nothing would work.

              I still have a few parts to that 68 (call it a 98) vacuum switches (Trico?) for door locks whole chrome armrest thing the switches can swap. Long ago it wasn't that old I junked it YOUNG day 1 with it was dark and Winter a windy -10F engine froze but ran had unknown damage totally gave up early or would still have it!

              Not funny I got it from a mechanic he said he just checked antifreeze - apparently just water in it! Bummer big time!
              MetroWest, Boston


              • #67
                The POA is a pressure regulator. It keeps the evaporator pressure (and therefore temp) from dipping below the frost point. It doesn't meter refrigerant, that is the Tx's job. It is there only to keep the minimum pressure in the evaporator.
                With this type control, the compressor runs continuously when A/C is called for but the evaporator pressure never drops below that at which it would frost over.
                Mopar product used a similar valve in the 60's and 70 called the EPR and Ford used both the GM POA and STV for the same effect. Once CAFE fuel economy became king, they switched to frost switches, which turned off the compressor when the evaporator temp dropped to the frost point, saveing a little gas, and being much harder on compressor clutches.
                Running the compressor all the time has some good points, the refrigerant is all stored in liquid form in the receiver when not needed and is available instantly, the low side is also kept at low pressure should the control need to handle more refrigerant. With a frost switch, the compressor is "off" when tripped, the low side pressure rises and the high side falls, then when more cooling is required, the compressor has to start under load ,pull the low side down and raise the high side to the condensing point.
                Since the valve is only a pressure regulator, the mass of the gas or its temp is immaterial to the set-point of the valve.
                For all the low side throttling valves, the set point is at or just very slightly below the pressure of the refrigerant at 32 deg F, this will keep the fins right above 32 deg F
                32 psi is 32 psi regardless if it is at -20 or +100 deg F
                If I had the choice, I'd use dry nitrogen for setting the valve rather than compressed air which will likely have moisture and oil in it.
                In Commercial refrigeration, a similar type valve is used on the outlet of an evaporator when more than one evaporator is used on one compressor and they are at differing temps, like refrigerator and freezer. It allows the low side to be low enough for zero deg in one evaporator and 32 or higher in another. By keeping the pressure up in the evaporator, it will not cool below the boiling point at that higher pressure.


                • #68
                  Somewhere I read special automotive fitting were designed for R152a around 2001 or 2003?? about the time they were also evaluating R1234yf. Both these refrigerants required changes to the classifications used. It used to be non-flammables were class A and all others B, Now they have changed that to A1 and then A2 for "slightly flammable (R1234yf and R152a) and B R290 and stuff like ammonia
                  Class B refrigerants can not be used in inhabited spaces without very strict limits on quantity of refrigerant used.
                  I do not know why R152a lost out to R1234yf but it seams to have.


                  • #69
                    IDK for sure. Follow the bucks - Dupont is/was HUGE probably would like to be a Monopoly? Rubber products, refrigerants and chemicals of all sorts brand named them.

                    Chances are 152a is so easy to make it's scaring the greedy so change the rules, make impossible fittings to tamper with all for a buck? Bet you!
                    MetroWest, Boston


                    • #70
                      Originally posted by Mikel View Post
                      I am doggedly trying to avoid using R12 (which has become cheaper than it was 15 years ago)
                      Not overly surprised that R-12 price should be going down, the worldwide demand for it is dwindling as old vehicles and refrigerators go out of use. But folks who bought R-12 when high most likely don't like to face their loss....


                      • #71
                        It is hard to keep things in prospective. By early 1990's everything automotive had switched to R134a, that was 30 years ago. 30 years before that was when cars just started being common with A/C. Yes, I know they were around before that, but it wasn't every car like it is today.
                        Both R12 and R134a have had about the same run in automotive applications. We only notice it more today because we are keeping vehicles longer than in the 60's and 70's.
                        In stationary HVAC refrigerants are changing ever faster. I can't keep up with all the new refrigerants and mixes that are being used today, and a year or two down the road there will be different ones.
                        The Chlorofluorocarbons were all about ozone depletion, The HFC's are about global warming potential (GWP), who knows what the next problem will be.