Well timing issue fixed, no to the a/c. Had my a/c clutch go and it had welded itself to the pump. New a/c clutch instructions recommended I replace the pump anyway, so tossed the old one got a new one. It's the A6 style giant one, had to find a buy 10oz of mineral oil for it too. That was weird. Usually that's in the freon. Anyway, all back together. I put 36 oz of the 134A(12A). It works good driving but at the lights it warms a bit. As far as I know that means it needs more 134A. I've never had one use that much, 36 is alot, and it wants more. How much do they take? I looked in the manual, nothing there. Online I've gotten 28-42oz. So what's the real number? Thinking I'll toss one more 9 oz can in there see what happens. Does anyone know the right amount?

 

Ok I got another can of 134A(12a, 9 oz. But reading the can it says the red teck 12a 9 oz is equivent to 24 oz 134a. That means I got 96 oz of 134a which is 38 oz 12a red tel pro stuff. So it's no were near over pressure on the gauge, and 4 cans seems normal, my f350 took 3 cans. Help? Confused. Guess if I put too much in I could just bleed it out?

 

you have wrong oil and refrigerant.. mineral oil is for r12.. i think 12a is propane and butane.. they may say compatible but if it was me.. i would either drain flush re - oil your choice r12 with mineral oil or 134 conversion with proper pag oil..
you should post your year.
i would rent get gauges to see where pressures are..

 

Sorry, it's a 73 with A6 pump. The long one. Red teck refrigerant is a synthetic product that's compatible with all systems, and quote there's no need to alter any system to use it. It's also equally compatible with all oils. So they say no need to change that either. Good point though for regular 12a or 134a. It also works on the 12 system. Guess that's why it ain't cheap. Thanks, any idea of capacity?

 

Get a set of gauges. I bought a set made for R134a, and bought adaptors.

As for getting hot at the stop light, have you considered an electric fan (or fans) conversion?

 

Your 73 Vette has a VIR (Valves In Receiver) that is non-adjustable for R-134a, you will never get R-12 cooling performance using R-134a unless you can reduce the Evap pressure from 29.0 psi (R-12) to 26.5 psi (R-134a) which you can't with that VIR. Having said that I have read that the miniature POA valve inside the VIR can be adjusted 1/2 turn counterclockwise to reduce the pressure but haven't looked into this.

You really need to have a set of gauges to properly service the AC system be it R-12 or R134a. Also note that unless your 73 Vette has GM TB 74-T-41 installed you will find that hooking up a hose to the low-pressure port on the VIR to be impossible without making a special adapter.

 

I think Ruby is referring to the A/C no longer blows ice cold at the traffic lights, then improves at speed.
This may be due to the real low RPM of the compressor. IDK

My A/C works perfect, in January, tops off, windows down.

 

Without a set of gauges, we may never know. The compressor shouldn't have an RPM dependency, if the system is filled correctly.

The lack of cooling air over the condenser is another issue. There is a reason that every modern car with AC has a way to supplement air through the condenser when at idle. The rad fan(s) will kick on. Even later C3s had this, with an electric aux fan.

 

I bought the conversion kit do its good to go for 12a or 134a

 

I think it's low rpm too. I have the carb solenoid on order until end of month for the rpm kick when a/c is on, so it does drop to about 600rpm at a light, 900 without a/c on. Doesn't get warm just not as cold as driving.

 

So, been trying out the a/c even tho the solenoid isn't here. Rpms get low at a light so for now I push on the gas 2 pedal style with brake. Lol. Still gets warmer at stops, even with rpm up. Do I put the single gauge back on with no bottle on it. (the gauge the cans come with for 134a.) the gauge with a/c on read in the yellow about 70psi. Do yellow bad, so I dumped a bunch of the gas until it reads about 45. It lost a bit of oil doing so, but not much. It has over a cup in it so not worried about that. Lost about 2 tablespoons. But it now seems to stay cold even at low rpm without solenoid, and maybe a bit cooler. Also, at 70psi the pump made a ticking sound on and off but now at 45 it does not make noise. I was waiting for the pump to turn off and on so I'd know I reached proper pressure, but it stays on all the time. So looked it up and apparently these pumps don't shut off they run all the time. So left it at 45psi, seems to be good there. I figure I had too much gas in there and the clicking may have been pump stress. Thankfully it seems fine and no longer clicks, and seems to be working right. Also my old pump used to turn on and off, that's what confused me, so not sure why it did that. Must have been part of it failing I guess. It did still cool until the clutch failed and ate sll the belts, lol. Hoping it's good now. Just waiting on this 250 dollar solenoid. Lol. Then I can use it all the time rather than in between lights. Hahaha.

 

So you no longer have a clutch on the pump, it runs all the time? And the system was overfilled before, so you dumped a third of it into the atmosphere?

 

Very often people think for the a/c is not cold enough they can just dump more freon in the system. Doesn't necessarily work that way. Pressure must be in the prescribed limits. Glad you are getting colder air now.

 

That Idle Stop Solenoid doesn't do anything different when the AC is turned on, its only function is to maintain the proper throttle opening when setting curb idle speed. When the ignition switch is placed in the run position a 12V signal powers the solenoid and the plunger extends, when the ignition is moved to the off position the 12V signal goes away and the accelerator spring tension pushes the plunger in allowing the throttle to drop to prevent engine run on.

On my 73 4-Speed car the curb idle is set at 900 RPM via the plunger and when I engage the AC the RPM drops to 500, weird for sure but that's how it works on my car. I think this is the same for 72 thru 74 Vettes that use that solenoid.

I was running my car yesterday with the AC engaged and while it did continue running at 500 RPM it was struggling, I think I need to bump that up a little and find a happy idle spot between AC on and off.

 

The instructions for the solenoid are to attach the solenoid and power to the a/c clutch on wire. As soon as you turn on a/c it pops out pushing the throttle raising the rpm. It then says either turn the plunger clockwise or counter clockwise to increase or decrease the idle to 900 again. Then it's set. Now when a/c is off your idle is 900 (no plunger), then when you turn on a/c the plunger pops out keeping you motor at 900rpm. The rpm should always be 900 at idle. Driving makes no difference than without plunger because at that point the plunger doesn't contact any more. So you need to turn your plunger out so it makes 900rpm with a/c on.

 

No, you need to read slower. I clearly stated I put a new clutch on and it is engaged the whole time a/c is on. It shuts off if a/c is turned off. I was stating that unlike new vehicles this pump is designed to run all the time while a/c is engaged. Were as new vehicles will cycle on or off during a/c cooling. I had never seen that before until I read up on this car. As for coolant. It was over filled. I had 4 9oz cans of red teck 12a in there. That's equivalent to 96oz of 134a. So I dumped it until pressure reached 45psi and now it works good. So probably dumped 1 can I'd say. And yes into the atmosphere since it clearly says it's harmless to the environment being a new synthetic gas. Works great now, cant wait for the solenoid so I can use it all the time rather than just when I'm moving. It doesn't stall when rpm drops but it's only about 500rpm so oil pressure drops pretty low when hot. So need that solenoid to kick it back up to 900 at idle.

 

I'm glad it worked out for you!

 

Yes that will work as well, mine is stock OEM so it works different.

 

What is the air gap set to on the clutch? Did you just run the nut down as far as you could when you installed it or did you set the air gap and stop there? No gap = Clutch is mechanically engaged permanently. The coil being energized or not by the circuit no longer matters because there is no travel for the clutch. Basically, the clutch is defeated so its always on.Air gap must be checked even if you bought a new compressor with complete factory installed clutch because they are often set up wrong. I always check air gap and also bench test the clutch on the compressor to verify its moving in/out properly.

 

The Harrison / Frigidaire A6 AC compressor is designed to run continuously and not cycle.