Random AC question

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MassDart

MassDart

Lifelong Dart fan
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Okay. So I'm getting ready to put the Magnum I built for my 67 Dart with air conditioning. I have never done a motor on a car with air before, so I have a couple of questions.
Is it safe to just disconnect the lines on the A/C ? Will it damage anything not having freon in the system while I'm putting the new motor in? Is there any special prep that I have to do? Should I disconnect the lines at the fire wall, or just pull them off the compressor? The AC still has the original R12 in it and the a/c wasn't it's normally ice cold last year, so I'm assuming that I'll need to recharge with R134 this year anyway, which by reading stuff on here, will need replacement of the drier anyway.

I've considered just unbolting the compressor from the block and moving it off to the side, but it seems like it'll be a real pain trying to put the new motor in with that in there.

Thanks for the advice.

Doug
 
If r12 works well then don’t disconnect. Remove ac from top side but leave connected and remove engine from the bottom side of the car.
Your ac system with r134a will not be the same. R12 is crazy expensive and letting it just fly is stupid for all the wrong reasons.

Plenty of articles in search feature to read up. Your car your way. My opinion is leave it sealed if you can.
Syleng1
 
MassDart said:
Okay. So I'm getting ready to put the Magnum I built for my 67 Dart with air conditioning. I have never done a motor on a car with air before, so I have a couple of questions.
Is it safe to just disconnect the lines on the A/C ? Will it damage anything not having freon in the system while I'm putting the new motor in? Is there any special prep that I have to do? Should I disconnect the lines at the fire wall, or just pull them off the compressor? The AC still has the original R12 in it and the a/c wasn't it's normally ice cold last year, so I'm assuming that I'll need to recharge with R134 this year anyway, which by reading stuff on here, will need replacement of the drier anyway.

I've considered just unbolting the compressor from the block and moving it off to the side, but it seems like it'll be a real pain trying to put the new motor in with that in there.

Thanks for the advice.

Doug
Click to expand...

The only concern about disconnecting it is environmental.
It doesn’t damage anything.
It will have to be evacuated anyway when switching to 134.
 
Moisture and dirt are the enemy of HVAC systems. Think surgery clean inside. If you have to disconnect lines, tape them shut asap.
 
Thanks for the replies. Rest assured, I didn't mean to make it sound like I was going to vent R12 into the air. I'm going to have it evacuated. I was curious as to whether or not, I needed to be careful with the lines being opened after with relation to humidity, dirt etc. Sounds like the best solution is that I will plug the ends when removed to prevent contaminates.

Thanks all!
 
I don't think your RV compressor will fit on your Magnum without modifications. I've never done it, but I'm sure someone on here has.
 
lemondana said:
I don't think your RV compressor will fit on your Magnum without modifications. I've never done it, but I'm sure someone on here has.
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I used EQ heads and they look like the bolt holes on them are the same, but I guess I'll have to take a closer look.
 
MassDart said:
I used EQ heads and they look like the bolt holes on them are the same, but I guess I'll have to take a closer look.
Click to expand...
Confirm you adapted the larger original A/C compressor to fit on your Magnum swap? Post some pictures of the install please.

If you are switching over to R-134, you can swap to a serpentine belt drive and the much smaller and more efficient Sanderson compressor. If you already have a functional, original compressor and R-12, it would be better if you keep it intact to save the hard-to-get R-12. Then just unbolt the compressor and tie it up and out of the way.

Another thing to change if you are switching to R-134, is to install a larger multi-pass, parallel-flow condenser designed specifically for R-134 and always change the receiver dryer when the system is opened. Both parts are available at the link below.


Consider pulling the engine out from the bottom, which is how I pull mine these days.
 
jbc426 said:
Another thing to change if you are switching to R-134, is to install a larger multi-pass, parallel-flow condenser designed specifically for R-134 and always change the receiver dryer when the system is opened
Click to expand...
Yup. I did the R12 -> R134a swap on my truck years ago, and as a Commercial HVAC guy I knew I was supposed to change-out the condenser coil.

But I was lazy, and I didn't, which was a mistake on my part, as I had head pressure issues from Day One with the R12 condenser.

Live and learn, I guess.
 
Not a big problem with R-12, though the mineral oil does absorb a little moisture. If you had R-134A, the PAG oil strongly absorbs moisture to form corrosive acids. Regardless, keep the tubes capped off if you unbolt. Don't leave open to the air for more than a day. I wouldn't change to R-134A since being outlawed. Why not a HC refrigerant like Duracool or Envirosafe. Works slightly better than R-12. People who claim it can explode are fools with no understanding of combustion. All refrigerant leaks can burn from the oil mist, though bigger problem is the condenser gets ruptured in an accident and refrigerant gets sucked in the running engine to come out the exhaust burnt. That makes poisonous phosgene gas with R-134A (WWI) and even worse HF acid with the new R-1234yc. Firemen learned to stay away from the exhaust after a crash. PAO 68 is the best oil for any refrigerant. Replace old hoses with new "barrier hose". If no ferrule crimper, you can get a slick look with Oeticker stepless ear clamps (ebay).

BTW, the whole Ozone Hole thing was a useless fuss. Negligible CFC's are measured in the stratosphere above Antarctica, yet the OH has been larger than ever since 2019 when it had shrunk and U.N. crowed "fixed it". It only occurs over Antarctica in Winter when little sun anyway, so the fuss seemed silly. Most reports of increased uV damage proved apocryphal. If you accidentally vent a little R-12, the planet will survive.
 
Very cool info. I didn't realize we had moved on from R134. Does using Duracool or Envirosafe require line changes? My originals are in really nice shape.
 
You can still find R12 if you look hard enough. Swap meets, garage sales, car friends that no longer need their stash. Ask around, you will be surprised.
 
If your hoses are pristine, you can keep using them. I recall that R-134A leaks a bit more than R-12 since a smaller molecule, which is one reason they switched to "barrier hose" which has an inner plastic liner. HC refrigerants are mostly a propane-butane mixture which might be a smaller molecule than R-12. At $10/can it won't be pricey if you have to add some every few years, vs R-12 which runs $100/can when you can find it. HC refrigerants work fine with the existing mineral oil from R-12. Not true for R-134A where you must totally flush the system and use PAG oil (or PAO 68, there was an Ester oil which worked w/ leftover traces of mineral oil). A few states or localities outlaw HC refrigerant, but I can buy in California. Duracool used to ship from Canada, but now stocks it in the States. If you have to vent some HC, that will be the same impact on the planet as a cow fart, which is actually a significant climate concern. Re safety, home refrigerators in Germany have used HC refrigerant for decades and no reported fire in the millions of cars using it for many decades. The EPA is cagey on HC refrigerant, still "considering the safety", for 30 years now. Absurdly, they require first converting to R-134A before converting to HC. Check there is no EPA drone watching you if doing at home and you go straight from R-12 to HC.
 
I still find R12 for 20-30 bucks a can. You must have been watching Fantomworks that one time when dickhead Dan charged the poor soul 1000.00 a can or something like that.
 
lemondana said:
I still find R12 for 20-30 bucks a can. You must have been watching Fantomworks that one time when dickhead Dan charged the poor soul 1000.00 a can or something like that.
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I had a can of R-12 on the shelf and a fill hose for it I no longer needed. Sold it on ebay for ~$60. Most others I saw advertised asked $100 for a can. Have prices dropped? Strangely, I found that can left on a bench over the river when out jogging ~10 yrs ago (nobody around), so grabbed it knowing it was gold, plus recall I still had R-12 in one car then.

Dan Short dropped the Fantomworks show, saying the filming was too intrusive on their work. I liked that they showed actual prices for their restoration work, which were often jaw-dropping for even basic mechanical work, but probably reasonable giving the labor hours and time spent sourcing parts. Only strange thing I saw was when a mechanic removed the upper ball joints in a Mopar A-body using a big pipe wrench. That works, but will mar the paint installing the new one. Must not have known about the special socket, which I have (both small and large ones).
 
As a follow up question, I see that Walmart carries the Envirosafe cans. How much will I need to refill the system, and can I do this myself?
 
Around here, not to many people use the R12. Usually at a swap meet, if I see some-I'll wait till right before I leave and offer a low dollar amount. They usually don't want to take it home. The last 6 cans I got were 20.00 a can. Garage sales sometimes are good, if there is a man around, just ask him if he has any around yet.
 
I was shocked at the pricing in that old Fantomworks episode as well, but personally I don't care what it's supposed to be worth, as the 12-13 pounds I still have left (from an old 30) ain't going nowhere.

As longs as my buddies still have R-12 cars that they want to keep as OEM as possible (Bazza's '71, for instance), they know who's got their back.
 
When the manufacturing ban on R-12 went into effect, the price on existing stocks got pretty high. I was working for Pennzoil Products Company and we started selling this for $30 a can. I sold a lot for a few years. A couple places that specialized in auto AC work bought it by the pallet. After a few years, demand tapered, and we discontinued it. I found this picture on the web.
frigc-fr-12.jpg




We sold this oil to use with it. This is in my garage.
IMG_20231107_183231456_PORTRAIT.jpg
 
MassDart said:
As a follow up question, I see that Walmart carries the Envirosafe cans. How much will I need to refill the system, and can I do this myself?
Click to expand...
Two 6 oz cans of Duracool works for me. You want to see ~35 psig on the low side with compressor running if a 70 F day and ~70 psig on both sides when off after sitting a long time. Yes, the cans feel empty, compared to a 16 oz R-12 can, but they work.
 
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