Calling C Body A/C Gurus 66 New Yorker

ctholl

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I’m trying to figure out if my a/c is running optimally or not. I have a 66 New Yorker with a gen 3 hemi. Using the compressor that came with the engine, new oem tube style condenser, new drier, new expansion valve, new evap core, and new custom a/c lines. Playing with r134 pressures and fan placement the best I’ve see come out the center duct was 50 degrees at 55-60 mph stop and go traffic has it at 53-60 degrees. This is at low 90s ambient.

Is this about what I should expect for my setup? It’s ok for the front seat riders, the kids in the back will not enjoy it.

Here’s a couple pictures of the setup. Everything is new and the box heater/cooling box was rebuilt.

Any help optimizing the setup would be appreciated!

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Just a thought...Not that I can be of any help but did the car have A/C originally ?
I ask because Had a customer car come in the shop that someone installed Vintage Air.
They didn't block off the vents for fresh air of non A/C and it was allowing hot outside air into the cabin.
Possible over charge ? too much oil ? I see you have a site glass too much oil will show slow moving bubbles.Just guessing. Low charge the compressor would cycle often/short cycle. Again just guessing.
As far as 50* outlet temp you should have approx something in the mid to low 30's at the vent outlet.
Possible not enough fan,but you did say you were traveling at speed so condenser air flow should be sufficient .
Using you gauge set you compressor low side pressure should cycle the clutch off around 15 and come back on at about 70-90ish.
Ambient temps, barometric pressure make pressures different so these may not be exact.
Nice set up you have, love the look. Good luck.
 
One other thing to note. Humidity. Possible evaporator freeze ? Notice less air flow from vents after it runs awhile ?
Drain vent open ? These are just thoughts that may help.
My stock 03 Ram would freeze up when I traveled in humid states. Again just guessing.
 
I'm not an expert when it comes to A/C but I do have some questions.

Are you using an evaporator core that is one unit with the heater core like the OEM ones or are you using separate evap and heater cores?
Is there a shut off valve to stop coolant from entering the heater core and making the evap core have to fight against the heat from the heater core?
Are any of the A/C lines close to exhaust manifolds or the heater hoses?
Some C Body's have a thumb-wheel knob on the floor duct housing to open and close whether or not some air blows out of the floor ducts. If your car has that, make sure that it is closed.
Just some thoughts.
 
Just a thought...Not that I can be of any help but did the car have A/C originally ?
I ask because Had a customer car come in the shop that someone installed Vintage Air.
They didn't block off the vents for fresh air of non A/C and it was allowing hot outside air into the cabin.
Possible over charge ? too much oil ? I see you have a site glass too much oil will show slow moving bubbles.Just guessing. Low charge the compressor would cycle often/short cycle. Again just guessing.
As far as 50* outlet temp you should have approx something in the mid to low 30's at the vent outlet.
Possible not enough fan,but you did say you were traveling at speed so condenser air flow should be sufficient .
Using you gauge set you compressor low side pressure should cycle the clutch off around 15 and come back on at about 70-90ish.
Ambient temps, barometric pressure make pressures different so these may not be exact.
Nice set up you have, love the look. Good luck.

-Original AC car
-I have it on “Max AC” for the test and the door actuates.
-I’ve tried multiple pressures starting from just barely turning the compressor to the high end of the range. The best performance was towards the high end
-I’ll take a look at the right glass later
-I don’t think the core is freezing over, but maybe ‍

I'm not an expert when it comes to A/C but I do have some questions.

Are you using an evaporator core that is one unit with the heater core like the OEM ones or are you using separate evap and heater cores?
Is there a shut off valve to stop coolant from entering the heater core and making the evap core have to fight against the heat from the heater core?
Are any of the A/C lines close to exhaust manifolds or the heater hoses?
Some C Body's have a thumb-wheel knob on the floor duct housing to open and close whether or not some air blows out of the floor ducts. If your car has that, make sure that it is closed.
Just some thoughts.

-Separate heater core and evaporator, the shutoff is new and working
-the suction line runs next to a manifold but i recently put a thermal shield on it with no change
-yeah I make sure all the ducts were closed underneath and used duct tape on any leaking spots
 
What are the high and low side pressures running as well as duct temperature when you have the a/c on max cool, fan at full blast, the windows down and idling?
 
On our '66 Newport factory a/c car, there were no operational issues with the factory system, when using R-12, back then. I suspect that only underhood items have been upgraded with the Gen III motor? With the extra pusher fan for the condenser, road speed should not really be an issue, I suspect.

One thing of note, in the summer, almost every service station which did a/c work also had a large fan whose airflow could be directed to the car's radiator area to ensure the a/c pressures (in the hot service bay) were more similar to what they were when driving on the highway at speed.

Which gets back to R-134a vs R-12. As to the total amount of gas in the charge. The old rule of thumb of charges, when converting to R-134a, was to start at 80% of the R-12 charge and work up to more gas, which usually ended at 90% of the R-12 charge weight for optimal cooling. Starting at 80% and adding gas slowly until the cooling started to decrease slightly, then stop there. R-134a is more sensitive to over-charging than R-12 was.

I'm suspecting you are using the Gen III engine's compressor cycling switch?

One issue can be that you are using an 8CID compressor to cool what a former 10CID compressor used to. A higher rotational speed can compensate for this, though.

All of the a'c ducts slide together loosely. In earlier times, some might have had a soft foam sealing them, which is now long gone. Re-sealing all of those duct junctions might help with air flow volume, I suspect.

Even when our '66 Newport Town Sedan was "a used car", how the a/c outlets were aimed helped with rear seat comfort! Usually, the center ducts were aimed to just clear the top of the driver's seat, angled slightly toward the rear outboard passengers, but not enough to bother the driver and rh front seat passenger. This might take a bit to perfect, though. Then use the side vents to help the front seat passengers get ventilation. Everybody wants to have cold air blowing in their face when they get in, but this will also result in lesser-effective total a/c cooling performance, by observation. Vent aiming can be key in good total system performance, even with 40 degree F vent outlet temps (40 degrees F was the standard, back then).

IF the system might be "freezing up", air flow will be diminished and when the evap core thaws out, the water can be smelled in the vent outlet air flow.

Side issue -- other than the jute padding under the carpets and sometimes above the headliner, the older cars were NOT nearly as well-insulated as modern vehicles are. Any insulation was more toward sound insulation rather than heat (including the cowl insulation). Can it be made better? Certainly, just might mess with the OEM production looks and such, but hopefully everything will be hidden and make for a quieter ride.

Just some thoughts,
CBODY67
 
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50's and 60's was all I got out of my motorhome after a 134 conversion...feels ok when its hitting you in the face but certainly cant keep up with interior volume...IDK what the volume/size of the compressor that came with your engine might be but late model stuff tries to be energy efficient for mileage and work in very well insulated cabins...if your pressures are OK I'd ditch the original style condenser and go for a parallel flow one as that's what modern systems are designed to use ...I couldn't try that with my motorhome due to the condenser and oil cooler being an integrated unit and I didn't want any additional fabrication initially and figured the results would be fine, but in retrospect i wish i had done it...that's why my Fury is going back together with R12...and sight glass condition isn't a reliable indicator of 134 charge that's why modern systems no longer use them
 
IMG_6917.jpeg


90 degrees ambient 50 percent humidity

This is at idle. Vent temp 62 sitting directly in the sun

At 2k rpm low side sits 25-27 psi vent temp 58
 
Is that fan pushing or pulling??
Duct tape and cardboard doesn't inspire confidence either.
It’s pushing flows great you can feel it pushing through the radiator very well and highest coolant temp I’ve ever seen is 192 in traffic. That’s some CAD (cardboard aided design) for some shrouding ideas (cardboard is free, aluminum isn’t) I didn’t want to do anything permanent until I knew what would work best. Because if I switch to a parallel flow I’d be doing it all over again.
 
"Parallel flow" is like a car radiator. More possibility of heat transfer than with a serpentine item.

Look for masticated rubber rather than aluminum. Usually in a sheet, similar to the upper control arm water shields. Your CAD can help with prototyping, but not much more. Also ensure the "yoke seal" on the bottom of the hood is operational, too.

As to pressures, in the old www.ackits.com website, they checked evaporator pressures with the hvac fan unplugged, windows open, and the compressor operating. 26psi was the target evaporator pressure in those tests, which resulted in 40 degree vent temps in all cases. R-12 was 27.5, as I recall. That was on cars where the compressor ran all of the time. With a cycling compressor system, might need to adjust the "on" time for best results (which I suspect would be where the current cycling switch would already be).

Seems like I ran across some parallel flow factory replacement condensers a while back. Usually in the $350.00 USD range? Might do a Google search for such?

Hope you can make progress in this situation,
CBODY67
 
Generally the low side pressure is the vent temperature or damn close, the high side, if I recall, is outside temp + about 140 degrees. You need to be pulling as much air through the condenser as the factory intended for every thing to work, you have to remove the heat or nothing will read correctly. The vent temp should get down to about 40 or so (the low side gauge will read this too) . I'm going to guess you don't have enough refrigerant in the system. Based on your gauge readings. When, or if you chose the add some, visually the low side tube (the big one) will start to sweat back to the compressor. Stop putting it in, and watch your gauges. If you need to, put a fan in front of the car and turn it on high. You may also notice the temp drop a little going down the road. That's normal, you can't suck more air through the condenser then the car will force through it. Good Luck
 
As was said parallel flow condenser. You can get them fairly reasonable. Just measure what size can fit.

In my case, the heater shut off valve leaked by a bit and heated up the air. Pinch off the heater hose(s) and see if that helps.
 
Shrouded everything up very well, got vent temps of 46 degrees at 60mph at 88 degrees ambient. I’ll keep messing around with it in between other projects.
 
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