midnight mechanic

Despite recharging the system, getting all the bubbles out of the sight glass, my car gets hot as hell in the daytime.

I think it is because the hatch back glass acts like a greenhouse.

I even painted the front consul white.

Toruki

Back in the 80's when my former GS ran R12, it was super great and I never had a complaint. It was better than the AC in my dad's Chevy Citation

My current GSL had no more refrigerant (R12) in it when I got it from the PO. So I converted to R134a and it's just not as powerful as I recall the GS/R12 being. I expected that, though.

I can say the greenhouse in these is amazing. I can feel the heat gain driving in the sun, and through a tunnel I notice AC works a lot better.

Humidity is a huge contributor to an HVAC systems ability to cool. The heat content in humid air is much greater than dry air.

Come out of shaded parking on a hot day, say 90-95°F, and it's good to go from the start. Having been in the sun, well it takes awhile to catch up from that.

And with the R134a it's more sensitive to lack of air flow across the condenser.

t_g_farrell

iTrader: (1)

If you used R152a (Computer DustBuster spray) it will be as good as with the old R12.

My AC is working great sitting on the shelf! I need to get hoses made and reinstall one of these days.

Toruki

Thanks t-g, that's interesting. When I converted to R134a I figured it would be leaking and need fairly regular top ups. But it's been pretty stable since then.

Off to the search button....

ray green

iTrader: (14)

I removed the AC systems from my FB's years ago.

Sitting on the shelf, as Tim says.

Took a lot of weight off, at least 100 lb as I can figure, that cast iron bracket is just plain stupid.

Dudes, it's a sports car. A two seater, mid-engined handling machine.

Light weight and affordable.

Totally cool without the AC.

Why screw it up with AC?

Toruki, get a grip. You live in Massachusetts, you only get 2 months of AC.

And the other 10 months are salt city.

No place for an FB.

Plus it's easier to get to the spark plugs.

peejay

Huh, got my latest RX-7 in large part because the A/C was still intact Still has a charge in it too despite the car last having run in 2009 or so.

In 1999, I converted my '80 to R-134a the easy way: evac what is left of the R-12, pull down to vacuum for over 45 minutes, install PAG oil and 85% the R-12 charge with R-134a. It would blow 34F out of the vents.

The RX-7s A/C system is stone simple. It's just controlled with an orifice tube and a temperature probe in the evaporator to switch the compressor off, keep it from icing over.

Toruki

They did just salt the roads 2 weeks ago <jk>.

Although you might have believed me, Spring was pretty cold here this year.

You are correct that we get about two months of quality Summer in MA. And during that blissful respite from the ravages North of the Wall (GoT anyone?) it can reach into the triple digits with high humidity.

And, Ray, I just can't take that. :P

Autumn is amazing, and you can generally go without AC.

I like the idea of R512 duster buster stuff because the word on the street is it takes less effort to compress, and I do notice the compressor working pretty hard.

ray green

iTrader: (14)

I'm just fooling with you on the AC Toruki, I lived in western MA for about 20 years, in the Amherst area and the hill towns. Pretty Liberal Territory back then, AC was considered an extravagance you should do without.

To get back to the original question, how's your AC holding up? I did try to maintain the AC systems in my FB's for several years, nice to have sometimes during the long hot Georgia summers when the FB was my only transportation.

But it seemed like I was forever working on my AC and with one exception they never really worked that well (I did have a brown 85 GSL with a killer AC system, I wish I new what the secret was in that one).

So after spending a weekend totally restoring the system on my light beige 84 GSL a few years ago, rebuilt the compressor and everything, only to have it barely work, I gave up.

And getting rid of all that extra weight and clutter does have its good points.

Toruki

Hehehe, if I can't take the heat...

(Western MA is beautiful. Ye, I remember when AC was an extravagance and added $1000 to the sticker.)

...install AC!

GSLSEforme

R134A molecules are larger than those of R12 and don't readily(as much as R12) seep/leak thru barrier hose,"o" rings and connections. This partially explains why system holds R134A charge better. It's a tradeoff,134 stays in system better/longer but is a less efficient refrigerant.

peejay

We were taught the reverse, that R-134a molecules are smaller.

When R-12 was discontinued, there was a lot of wailing and gnashing of teeth by the anti-progressives because supposedly R-134a would leak through hoses and O-rings that were sufficient for R-12. As it turned out in the real world, a combination of residue build-up on Old Hoses, and then-contemporarily modern hoses being made with the correct barrier materials even for R-12 applications, made this "problem" a non issue.

Yet you still occasionally read from people who scream and cry over how you can't convert an R-12 system to R-134a without it leaking all over the place and having crappy cooling. Those of us who have done, literally, hundreds of conversions, shake our heads in condescending sympathy. Fortunately, the complainers have mostly moved away from tilting at that windmill to blaming ethanol in fuel for everything bad that ever happens, even though some of us have been on 10% ethanol for over three decades with none of the ill effects they claim happen.

MODERN A/C systems aren't so great, when you have a tiny condensor for low frontal area, a tiny compressor for packaging reasons and less parasitic loss, and a tiny evaporator for more in-cabin room, and the combination of all three means a lower refrigerant charge for minimal refrigerant in the vehicle. Where 2-3lb used to be a normal charge, a lot of cars only have 12-16 ounces of refrigerant. So of course air conditioning is going to suffer. The modern A/C paradigm is 30 degrees cooler than ambient. So on a 95 degree day, blowing 65 degrees out the vents is acceptable. That will keep you from overheating but it won't be comfortable.

It's not because of the type of refrigerant! Convert an old car with a condenser the size of a mattress, a compressor the size of a watermelon, and a gigantic evaporator, and it will still cool awesome with R-134a. I remember my first car had a 4.5 pound R-12 capacity and I would charge it with only 2 pounds because even back then R-12 was $60-70 a pound (it was $120/lb when I converted my RX-7) and the system was so huge and the cabin so small that the cooling was acceptable.

The A/C system in an RX-7 has what would be classified now as a large compressor and a huge evaporator. The evaporator is about as big as what is in some vans. The condensor isn't the best, though, and I wonder sometimes about swapping a modern ultra-high-efficiency condensor into the car.

GSLSEforme

R152 is not AS good as R12 but very close. Have converted a couple vehicles with it and performance is about as good as R12 but not quite.
Have a 27 yr old Buick that until a month ago still had its original charge of R12 and worked very well,til a rock hit to condenser changed that. Same thing happened to my SE about four years ago...
I'm sitting on 1.5 cases of R12,but decided to try R152 in the Buick. Flushed system,replaced condenser,changed accumulator,changed refrigerant oil,pulled a vacuum on system and charged with R152. Results 39 degree air from vents which is quite good,previous R12 charge had 33-34 degree air coming out so there is a bit less efficiency with R152,but much better than converting to R134A.
2nd vehicle,my Tacoma pick up. A/C always worked good in it(R134A system)about 40 degree consistent vent temp. Some type of debris hit outlet tube on condenser. See a pattern here?...Replaced condenser,accumulator,flushed system,changed refrigerant oil,pulled vacuum and charged with R152. Now 36 degree air,compressor quieter,cycles off sooner than previously(reaches lo temp cutoff quicker) slight improvement in gas mileage with A/C use than previous. Attribute improvement to more efficient refrigerant. This conversion has 3+years on it.
3rd vehicle,my SE. Replaced condenser(thanks again,Ray!)flushed system,replaced drier,changed refrigerant oil,pulled vacuum on system and charged system with R152. 38-40 degree air output from vents,previously 34-36 with R12,compressor cycles off less frequently than with R12 so this system is slightly less efficient with R152 than R12.
Never considered a 134 retrofit with this car having done so many others on many brands of vehicles,most never worked as good as they did with R12 because condenser/evaporator area was marginal with R12 as the refrigerant. Customers learned to live with a less efficient A/C system as alternative was no A/C at all...

DivinDriver

iTrader: (15)

I'll let you know if I ever reinstall it. Haven't been able to find a new receiver/drier with the proper connections (port air flares, not factory air o-rings).

Qingdao

iTrader: (3)

I'll let you know if I work out a solution for this issue... as it is my current issue for the no A/C situation.

I've been thinking a journey to Fastnel is inevitable.

DivinDriver

iTrader: (15)

It's weird - sources I can find that sell the port air compressors and condensers carry only the factory-air RDs.

peejay

Stuff like this is why, if/when I have to tear into it, I'll probably just splice in a condenser and accumulator from a Corolla or something, with A/C hardline compression fittings.

midnight mechanic

I should of stated that I'm in Alabama. The humidity and sun are brutal down here. My a/c offers only feeble relief. Maybe it needs a new compressor? A new condensor, new evaporator......??

KYPREO

My A/C works brilliantly.

I swapped out the 85 RX-7 compressor and bracket for a 13BT setup from a 91 FC. As noted above, the 1st gen bracket is cast iron and weighs a ton. I cut down the FC alloy backet to remove the power steering mount and it ended up weighing less than 1kg. I think it was at least 5kg lighter (11lbs) than the 1st gen one. The compressor is also more compact and sits a lot lower, making it less obstrusive and obvious.

In Australia, we can't charge A/C ourselves - by law, it has to be done by a licensed A/C fitter. I don't even think consumers can legally buy A/C gas. That said, it cost me $100 to fit the lines, new receiver/drier and charged up with new gas. I used ER12 which is a drop-in replacement for R12. It performs brilliantly. Ice cold. Reportedly much better than R-134A.

I just pulled the engine and after 10 years, the system was still full and performing like the day I got it recharged.

GSLSEforme

KYPREO,do you have any info on the ER12 refrigerant? Curious,thanks.

GSLSEforme

Did you charge system yourself? Does the ac compressor engage?Do you have a manifold gauge set to post some lo & hi side operating pressures of your system here to help with diagnosis? What type refrigerant and how much was put in system?
Need to know these #s to point you in right direction. How old is receiver dryer,did you pull a vacuum on system before (re)charging?

KYPREO

ER12 is the trade mark for a hydrocarbon-based non-HFC refrigerant marketed by Australian company, Boral Energy. I understand ER12 is basically a refrigerant form of LPG (liquid butane/propane composition), which coincidentally is what I am using to fuel my 13B turbo engine. It is 60% propane and 40% isobutane.

It may not be available as a refrigerant in the US.

These are the best sources of info I could find:
https://hychill.com.au/content/3-inf..._report_sm.pdf
http://www.iafss.org/publications/fs.../fss_9-615.pdf

midnight mechanic

I charged it myself with r134, have put in leak sealer and a/c oil last year. The compressor engages. No manifold guage set. Everything is OEM or has been in the car since 1990 (when I bought it). No I didn't put a vacuum on the system.

And one small can usually removes viewing sight bubbles.

Also, at one point I sprayed white plastic dip on the roof. Didn't make a difference. The glass rear hatch is tinted, which improved things.

thanks!

GSLSEforme

Thanks for the info. Yes,that's not available in this country. Certain wouldn't pass flammabiity standards for refrigerants here. There are some refrigerant blends sold here containing some of those components but are not legal.

GSLSEforme

Would recommend having a shop put gauges on car to see what's going on presssures wise. Could be overcharged,could have a blockage in system(dryer failure allowing release of dessicant).
Any diagnosis needs to start with reading system operating pressure. A/C in these cars perform fairly well when working properly.

Stevan

iTrader: (17)

From what I've read about using the sight glass, it's generally not used with 134a, they were designed for r12. I believe you should see a few, occasional small bubbles, not clear as with r12. So you may be overcharged.

The problem with our cars is the condenser size and placement combo. It "may" be barely big enough size wise, but because of the size, you can't put it anywhere and not allow air to bypass it all around, so especially dismal cooling while sitting in traffic with the least amount of airflow.. If you could stretch the condenser (same amount of tube and fin with wider gaps between it all) to fill the opening in front of the radiator, thus forcing all the air to have to go through it the system would likely be adequate.
I'm using a condenser from an FC, its not a lot larger, but it's wide enough to span the width and I have a piece of sheet metal going from the top of the fmoc to the bottom of the condenser, air can't bypass it. The system works very good with 134a, and it's f'n hot here.