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Post by Charlie on May 23, 2020 3:03:12 GMT -5
The A/C in the 1971 model... does the compressor cycle on and off using a thermostatic switch, or is it a pressure switch in the line?
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Post by Nacho-RT74 on May 23, 2020 4:12:13 GMT -5
All are controlled by pressure valve built/installed into the compressor outlet, not electrically on off cicle. Compressor never gets on/off, just stays on while AC is on
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Post by Charlie on May 23, 2020 11:18:27 GMT -5
Was this the same for other Mopars of the time?
I clearly remember my 72 Duster cycling on and off once it got cold in the car. It took one can of R12 every two years and was never converted to 134. I think the only thing I did to it was change the condenser and dryer back in the early 90's... due to a failed fan clutch. The a/c in that car worked pretty damn good till I sold it.
So if I replace the original compressor with a Sanden unit, is there a valve I can install for the different pressures involved with 134?
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Post by Nacho-RT74 on May 23, 2020 12:04:29 GMT -5
As far I know all Mopars on those days were the same. I know earliers B bodies ( and mostly sure all C bodies ) got a delay system for something that I can't recall.
I'm not expert on this, but just talking about what my car is.
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Admin
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Post by Admin on May 23, 2020 13:48:44 GMT -5
That was my impression too...the old a/c systems with the iron RV2 did NOT cycle on and off. They run constantly. And to be honest, with the drag that big V-twin compressor puts on the system...who would want that thing cycling on and off? Would be very annoying.
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Post by Charlie on May 23, 2020 14:17:36 GMT -5
Interesting! Well thanks for THAT enlightenment! Learn something every day!
I could have sworn my Duster would cycle... hell I drove it for over 20 years. I had assumed (during my Duster days) that there was a thermostatic switch making it cycle. I guess since I never had to do anything other than replace a blown condenser, I never had the opportunity to learn the way that particular system worked. I knew the evaporator leaked a little... a can every two years was all it ever needed. Since it never got any worse than that, I didn't worry myself with changing the evap. And when I sold the car back in 2011, I still had two cans of R12 to give to the guy that bought the car.
So for my current system, will I be able to get a valve that operates at the pressures designed for 134a? I would assume it doesn't matter whether I buy a V2 or a Sanden... I would still need a regulator valve that's specifically for 134a.
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Post by Charlie on May 23, 2020 14:19:39 GMT -5
How does the temp control on a 71 work? It's electric... no cable involved... so is there some kind of little brain that's working the heater control valve?
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Post by Nacho-RT74 on May 23, 2020 15:52:37 GMT -5
Interesting! Well thanks for THAT enlightenment! Learn something every day! I could have sworn my Duster would cycle... hell I drove it for over 20 years. I had assumed (during my Duster days) that there was a thermostatic switch making it cycle. I guess since I never had to do anything other than replace a blown condenser, I never had the opportunity to learn the way that particular system worked. I knew the evaporator leaked a little... a can every two years was all it ever needed. Since it never got any worse than that, I didn't worry myself with changing the evap. And when I sold the car back in 2011, I still had two cans of R12 to give to the guy that bought the car. So for my current system, will I be able to get a valve that operates at the pressures designed for 134a? I would assume it doesn't matter whether I buy a V2 or a Sanden... I would still need a regulator valve that's specifically for 134a. postimg.cc/gallery/ChwjbjBdunno If I miss take the pic to some page of this article on the magazine. But magazine is in Vzla and I'm In Spain right now
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Post by Nacho-RT74 on May 23, 2020 15:53:33 GMT -5
How does the temp control on a 71 work? It's electric... no cable involved... so is there some kind of little brain that's working the heater control valve? I never have seen anykind of unit control for 70s A or B bodies, just some vacuum system on some models ( specially 71s ) and cable operated on other some models for the heater valve control. The mix of warm and cool air inside the box is what sets the temperature. You can only change the ammount of hot water getting into the box and that´s what change the total temperature
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Post by Nacho-RT74 on May 23, 2020 16:06:52 GMT -5
for more, here: www.imperialclub.com/Repair/Lit/Master/295/cover.htmalthought there makes mention to a thermal switch for temperature sensing for compact cars ( maybe that's why you had it on your Duster ) I stil have never seen ever that stuff on any 71/74 B body at least. Is not on wiring diagrams or anywhere. on the INTERMEDIATE cars sections, talks about the EPR valve which is the one I talk
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