What did you do to your Supra today? - Page 349
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  1. #3481
    CelicaSupra.com Member
    Join Date
    May 2019
    Quote Originally Posted by supraz View Post
    I've been working on the AC. The compressor had a massive leak at the shaft seal. I replaced compressor with a new Four Seasons Denso unit, the front end O-rings with Green HNBR R-134a compatible O-rings so I can tell whether they are Nitrile or HNBR, new Denso condenser, and Denso Reciever-Drier.

    I took the opportunity to clean off 36 years of grime.

    Attachment 8713
    New Four Seasons compressor with the original manifolds cleaned up and attached

    Attachment 8715
    New Denso condensor and Receiver-Drier with cleaned up fan mount and fan

    Attachment 8717
    Cleaned up the compressor suction and discharge hoses

    I took her in to my local Radiator shop to be vacuumed, tested and filled. I'm of course feeling pretty cocky about my car. Well, each time I go, I get brought down to earth by other customer cars!

    Attachment 8723
    1933 Ford 3 Window Coupe with 409 Big Block Chevy

    Attachment 8721
    1958 Ford Thunderbird

    There are some shops that I just LOVE going to.
    stay cocky just as your looking at them saying nice ride I bet they are doing the same

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  3. #3482
    CelicaSupra.com Member AJ's Avatar
    Join Date
    Mar 2003
    SF Bay Area
    Moved a bunch of MK1 manuals and Toy Tech handbooks into the garage that I had put aside to sell...no one has contacted me so back to the garage for the time being...
    '86 Supra MA67
    Brullen 2.5" Exhaust, HKS Fly w/7MGE clutch,ST Springs, RC Intake & TB, 2.8GT & XX emblems, Factory Add on Rear Shoulder belts, Pioneer DEH-P2000 AM/FM/CD w/CDS-P5000 CD Player, Compomotive CXNs 8x16

  4. #3483
    CelicaSupra.com Member
    Join Date
    Jun 2013
    England, UK
    Quote Originally Posted by supraz View Post
    The AC effectiveness of the original system with R12 when the car was new was definitely marginal. By comparison to typical American cars, the AC would cool you, it would not freeze you. So as to whether my system with R134a works as efficiently as with R12 is difficult to say. I had my system switched by a Toyota dealership in 2000 and had not measured dashboard vent temperatures before and after.

    I have been reading about vent temperatures of what some people have been achieving with properly functioning R12 systems and they are certainly achieving cooler temperatures than what I am with my R134a system. Naturally, by the time I fixed my AC system, the weather changed and got a lot cooler so I can't tell how it works in hot weather.

    For fun, I measured the vent temperatures of my 2017 Ford Flex AC beside that of my 1983 R134a filled Supra, and the Flex vent temperature was about 40 Degrees F versus 45 Degrees F on my Supra. What I found really interesting was that the AC on my Flex froze me while that of the Supra cooled me. I suspect that it has to do with the interior blower fan speed/volume. The Supra vent size and blower fan speed are mediocre compared to more modern cars.

    I have read, and would tend to believe that increasing the Condenser fan size and/or replacing the Condenser with a more efficient design would improve the performance of an R134a filled system. Apparently, despite common perception, R134a is actually a more efficient coolant than R12.

    A customer of mine who is a scientist, and a car buff, told me that the diffusion rates of R134a and R12 shouldn't really be much different. He states that the O-rings used in automotive AC systems do not actually seal the coolant into the system. It is the lubricant oil circulating in the system that seals the lubricant. It seals the small gaps between O-ring and fittings, and the oil also seals the pores in rubber hoses. He stressed that running the AC system occasionally to keep the oil distributed properly is crucial. This is something I have NOT been doing and it makes sense. Another reason to fire your car up occasionally even if you have it in storage.

    I waited until my compressor shaft seal started leaking (it was REALLY leaking) before I decided to work on the system. A vacuum test wouldn't hold pressure. I had the AC shop drain the remaining R134a and then I bought O-Rings, Receiver/Drier, Condenser, and compressor online. I changed the parts myself and saved a ton of money. Once I had installed everything, I brought it back to the AC shop to vacuum out, leak test, and fill up. While not cheap, it was a lot less expensive than having them do the part changing.
    As long as you don't wait too long between the time you rebuild the system and have it evacuated, moisture should not significantly effect system efficiency.

    I'm going to find out how well I sealed the system up. The compressor I purchased was a Four Seasons branded part that was advertised as new. I'm not sure I believe that. The pump looked new, but there were Denso part numbers on the part indicating that it was a Denso rebuilt pump! Four Seasons didn't respond to my request for clarification on this.
    The funny thing Dale is that my dad raved about the Supra's AC when he owned it, claiming Toyota had taken the AC system out of a larger vehicle for the Supra and for that reason it was overpowered for the size of the car. My experience has been that the AC is certainly effective, particularly on recirculate, but oh boy does it make a dent in the fuel economy! Add to, when the compressor engages, the 5M noticeably 'flinches', and the higher idle speed makes it a real pain to use in stop-start traffic...

    We didn't get much of a summer this year so my efforts have been mostly wasted; Dragon has just gone back in the garage for winter and it's likely I won't start the engine until next spring, let alone run the AC. At least the conversion company indicated the vacuum test was good so at least the seals haven't outright perished with time; my dad told me that keeping the oil flowing through the system was vital to holding in the gas. Running the AC once a month is supposed to be the ideal.

    The company I went to indicated that pretty much the entire system would need to be replaced, including the pipes, since the tolerances would be much tighter for R134a (they even suggested that the R12-spec metal pipes would actually leak R134a! That's the point when I started to wonder if they actually knew what they were talking about...).

    And that's naughty of Four Seasons, but I'd imagine nowhere would actually sell 'brand new' non-service parts for the MKII any more. Still, you've arguably got the better component if it's a rebuilt Denso - it's likely been on a Supra before and we all know how good quality Denso components are.
    Rob - 100% British
    Hidden Content
    "Dragon" - 1986 White P-Type (UK model), 5M-GE, manual, digital dash, cone air filter & stainless-steel exhaust, 176HP, Beloved DD
    Hidden Content | Hidden Content | Hidden Content | Hidden Content

  5. #3484
    Join Date
    Aug 2019
    Auburn AL
    Quote Originally Posted by Gargravarr View Post

    The company I went to indicated that pretty much the entire system would need to be replaced, including the pipes, since the tolerances would be much tighter for R134a (they even suggested that the R12-spec metal pipes would actually leak R134a! That's the point when I started to wonder if they actually knew what they were talking about...).
    Your Dad's right about running the A/C. Just like leaving an engine sitting the seals dry up. I never saw an issue with "tolerances" and 134 so I'm not even going to suggest that you misunderstood about the "metal pipes" leaking. But when r-12 was being phased and we were doing a lot of retrofits to 134 we generally replaced the rubber hose sets with a barrier hose. It was lined with a "solid" nylon or Teflon liner because even r12 would leak through the straight rubber hoses as they got older and 134 definitely would. Don't know the science but maybe 134 has smaller molecules.

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