A/C system

Topic: A/C system (Read 11843 times) previous topic - next topic

A/C system

May 13, 2013, 10:47:52 AM

I'm looking to buy a new A/C set up for my car. I was wondering if they have come a long way compared to my 27 year old original. Also where can I buy one. I own a 1986 Cougar with a 5.0 HO engine. Thanks!

A/C system

Reply #1 – May 17, 2013, 11:12:49 PM

Quote from: jcassity;415069

the stock compressors are fabulous in design with respect to all things mechanical and electrical... your choice though to go vintage air.

not sure if you got a quote yet or not, im not really sure where to point you. your stock compressor is really over built, one thing of many ford did imho.

are you thinking the compressor is burned up? or is it just the clutch that is not kicking in?
sorry, thought i saw on your other hvac post that you mentioned it was cooling nice and good.

A/C system

Reply #2 – May 17, 2013, 11:39:34 PM

Jay i thought the AC system was up and running . Has things changed???? The ford system is quite adequate and has a rating somewhere around 3 1/4 TUNS. Bigger than most other cars on the road. And the compressors on these cars are one of the best on the market. What would be accomplished with a vintage air swap. I use Vintage all the time in cars that do not have AC. But what would someone with a sytem that is supposedly working want to rip out a perfectly good working system. I am lost for thoughts on this one!!!!!!!!!!!!

A/C system

Reply #3 – May 18, 2013, 12:58:22 AM

Quote from: 86cougar;415060

I was wondering if they have come a long way compared to my 27 year old original.

Mechanical things like pumps haven't really changed. If you're looking for the best of everything, I can recommend the 97 Cobra condenser. I have my A/C system setup to provide continuous vent temperatures in the upper 30's during the hottest days when on the highway. The vent temperature is in the upper 40's when sitting in stop and go traffic as the compressor isn't compressing the refrigerant quick enough and there isn't the large amounts of airflow over the condenser. In cooler temperatures, the compressor cycles a bit since the entire system is borderline low on refrigerant, but I set it up for the coolest temperatures on the hottest days and I didn't care about it as much when under 80F. I think I set it up with a charge to get me 22-24F at the evaporator, which just barely does NOT freeze over. I don't think you can get a cooler A/C system than this. When I first did it, I was so excited that I kept it on max all the time, with the vents blowing at me. Once I got out of the car after a 40 minute highway drive, on a 90+F day, I found that the skin on my right hand was cold enough to stay chilled outdoors for a few minutes before it warmed back up.

This was with a new compressor (old one was dead after sitting "not working" for a decade) and conversion to r134 refrigerant/oil. I don't remember the site I got the parts off of as it has been years. It was some A/C specific website that provides everything for the conversion. I purchased new liquid and gas lines also, along with a new accumulator.

Our systems can work great. I enjoy the r134 conversion after a condenser swap. Of course the oil isn't compatible between r134 and r12, so you'd want to flush everything out the best you can.

A/C system

Reply #4 – May 18, 2013, 06:38:23 AM

Normally the AC systems today use electric fans to keep air flow over the condenser stable in traffic. And normally the compressor pulley size was changed a bit when RA134A came on the scene with the engine in traffic. Condenser size is critical on 134A but if you look at the tables the two freons are almost exactly the same performance wise. But i am going on record and saying the ford compressor on these cars are well able to handle any AC requirements one might encounter. The double air system on stretched limos use the same compressor. As the matter of fact ford has a bigger compressor for like SCHOOL BUSES with double air but they are not necessary. Also his car is a CCOT and that in itself is a high performance unit. Just a question SEEK how do you keep evaporator freezing up with 22-24* evaporator temps??? I am puzzled at how you accomplish that. And how do you get those temps when the stock setup kicks at 32 LBS Gauge??? (low side)

A/C system

Reply #5 – May 18, 2013, 12:02:51 PM

i did some web crawling , there seems to be several options out there for aftermarket HVAC support in cars.
I would not know the differences in choices though, would have to do some reading and asking around.

post up some pics of your new system when you get it in, this may become a necessary evil for all of us one day and the data would be important.

A/C system

Reply #6 – May 18, 2013, 05:52:28 PM

Actually guys, it was just a question. The A/C system on my car is all original and I was just wondering if it decides to die on me, I want to know what to look for. I just came back from a 260 mile trip and my girl friend and I froze. I had to turn the fan on low and the temperature down to about half way as far as cooling. It's good to hear that these compressors are so well built. I guess it's like "Seek" said that not much has changed, probably because what we have works so long and so well. Thanks!

A/C system

Reply #7 – May 18, 2013, 08:54:59 PM

Did it freeze UP. If so that means only two things. THE CCOT switch is stuck closed or it is BYPASSED. That system can not freeze over unless the CCOT switch is shot or bypassed.

The CCOT system is so simple it is not necessary to look else where for components. There are many new and rebuilt compressors around for replacements and any other part needed for this unit. The system does not have any moving parts in the system other than the COMPRESSOR and leaks !!

A/C system

Reply #8 – May 18, 2013, 09:00:26 PM

Quote from: TOM Renzo;415434

Just a question SEEK how do you keep evaporator freezing up with 22-24* evaporator temps??? I am puzzled at how you accomplish that. And how do you get those temps when the stock setup kicks at 32 LBS Gauge??? (low side)

The low pressure cutoff is adjustable with a screw. I believe I have my cutoff set to 20psi, which would put the refrigerant at 22F at the switch. This also means the refrigerant is 22F at the entrance of the evaporator, but it heats up as it travel through. I'm not sure what it is on the other end, but it'll be a bit higher. Let's say the evaporator is sitting at 25F and the blower is circulating air that is 60F - it is pushing air through the evaporator that would prevent the thing from freezing solid, but there COULD be a thin layer of ice on the evaporator's fins. For any real information, I'd need something like a lab-grade humidistat, preferably a camera in the evaporator box so it remains sealed, and a ton of measurements to make any real statements to back up why my setup works. I just know it's setup for 20psi cutoff and that it blows sub-40F out the driver side vent to the right of the steering wheel using a Fluke contact thermometer. It's basically the same reason I don't see ice on the liquid line - it's near the exhaust, but that is a far greater temperature difference.

Also from what I understand, the oil in the system may not lubricate well/thorough at <15psi low, but that was just going off of research 4 years ago. It would also be much more likely to freeze over as 15psi would be 15F.

It works for me but I can't say it would work for everyone. I do have an electric fan on the car, but do not run it higher when the A/C is on. I'm pretty sure the condenser is doing a LOT of the work for me.

I should also mention that iirc, at 630rpm idle, the A/C compressor can't keep up at all and it blows like 15 degrees warmer than when holding it at 1k rpms. If memory serves me right, it was like 38F on the highway at a steady speed in best-case (I don't remember the cabin temperature) after 10+ minutes of driving, 45-ish with the car not moving and the rpm's help at 1000, like 60-ish just stopped and idle at 630rpms. This was back when I was running a mechanical fan with a new fan clutch. I think I may have a thread on it some place, from likely summer 2009.

Edit:
I will also say that I haven't driven that car in the hot summer heat for years now since it is no longer a daily driver. I could completely remove the A/C in this area now and not care, but I'd prefer to keep it on. My last experience with any of this was 2 years ago, and it had been on the car for 2 years prior without any issue. I don't remember the condenser temperatures or pressures, but they were high and hot. I also do not remember if I have the liquid line with the stock restrictor. I think it's the stock sized static unit - not one of those variable units that is supposed to help idle cooling (as seen above) that people seem to strongly dislike for reliability. I'm sure that is the one thing that would drastically help our systems with r134 though - a different restrictor.

A/C system

Reply #9 – May 18, 2013, 09:09:24 PM

Ok so you ran the set screw down to stop the clutch from dropping out. But i am amazed the evaporator does not FREEZE UP. Also you are running low on refrigerant with a steady low side of 20 LBS Gauge.That system is down charged 20 LBS way down charged!!!

A/C system

Reply #10 – May 18, 2013, 09:24:02 PM

Quote from: TOM Renzo;415476

Ok so you ran the set screw down to stop the clutch from dropping out. But i am amazed the evaporator does not FREEZE UP. Also you are running low on refrigerant with a steady low side of 20 LBS Gauge.That system is down charged 20 LBS way down charged!!!

As long as it's oiled adequately, I don't care that it's lower than normal. It can cycle all it wants on cooler days - I wanted the coldest temperatures on the hottest summer days. I grew up without A/C and always told myself I'd built one to make a car a mobile freezer (I had pictures in my head of ice forming on the windows). While I later learned why this wasn't possible, I could get close. It hasn't leaked out yet as far as I know, but I'd need another warm day to test it out this year. Not saying I'm an expert on these things, but I did my research and didn't see any reason for problems as long as I don't get my evaporator frozen up, which would make the cooling halt. If I was building a mass-produced vehicle, I'd want to be on the safe side too to get less warranty work. There is some extra to be obtained from the A/C system though, just as there is extra power to be made from the 5-liters of displacement. Everything can be modified to work on the brink of destruction, but if you plan beforehand, install everything correctly, and know how to monitor everything and use quality parts, things generally last.

I probably have 50 or so hours on the system. We rarely need it here. For all I know, the system could be inadequately oiled, but I haven't had a problem yet. I'd have better anecdotal data if I lived in the southern states. Still yet though, that car has been a garage queen for over a year now.

A/C system

Reply #11 – May 19, 2013, 06:15:30 AM

Well there is two sides to this story

1 The system is modified to do something it was not designed to do but the outcome satisfies your needs. Nothing wrong with that!!

2 It shows that the system is strong enough to TOLERATE IT.

So that answers the question that the system does not have to be replaced as 86 wants to do.

Your post confirms my post as the system is totally adequate to cool these cars with out any issues.

Just a thought !!! Running the system this way is most likely OK for your enviorment. (Where You Live ) But in a HUMID HOT CLIMATE the system is not working correctly and God only knows why it does not freeze over. Either way i appreciate your post as it helped what i was saying. Thanks!!

A/C system

Reply #12 – May 19, 2013, 09:45:29 AM

With all that being said, there seems to be a concern about freeze up. My car is a freezer when I turn my A/C on (no complaints). If it is running too cold this is where the possibility for the compressor to freeze up? I am running 1.9 lbs. of R134 and if I understand right that is about right for where I live. If I only turn my temperature control about 1/2-3/4 up would that help prevent freeze up? If I turn the set screw up to where where the clutch drops out more would that make my system not work as hard or be better for it? Like I said, I don't want to replace A/C system, I just wanted to know what to look for if and when my system dies.

A/C system

Reply #13 – May 19, 2013, 12:54:26 PM

The A/C system running extremely cold can only have problems if there is moisture IN the closed-loop system of refrigerant. When you pull heavy vacuum before charging a previously-open system, you remove nearly all of this moisture. The concerns of the evaporator freezing up would only clog the fins up with ice, making it so you get no airflow through it, and no cooling. This won't harm the system, other than the expansion and contraction being more than normal, eventually wearing out the evaporator a bit quicker (give anything enough time, it will begin to fall apart, and in this case, means it would start leaking). I wouldn't be concerned about the evaporator though, and unless you've modified the low pressure cutoff, you are still getting a 35-37F temperature from the condenser at best, which could get you 45-50F out the vent best-case. On a hot day, this will still seem very chilly.

A/C system

Reply #14 – May 19, 2013, 02:16:10 PM

Seek the system freezes the condensed moisture on the OUTSIDE OF THE EVAPORATOR surface. That is why the system drops out at 32 Lbs or app 35 lbs low side. That equates to app 35* across the evaporator so it does not freeze. A quick look at a properly working unit will have water coming out of the condensate tube. That is what you are concerned with when evap temps and clutch drop outs. The reason the clutch drops out is so the EVAPORATOR does not freeze up. It has nothing to do with the moisture in the system. Thanks