After converting my 71 comet GT to 134a with an engine bay conversion from Classic auto air in Tampa, I ran into a few problems. I quickly found out that our cars have lost data when it comes out to filling our systems with R12/134a. You can really go by the engine bay stickers. They say running 80% of R12 is correct for 134a but even this ends up with too much freon in the system, so I thought I would post my findings for anyone else who may install a conversion system or have unanswered problems. First issue is that 134a conversions do not work well with the stock condensors, or at least in hot places like florida. If you live in Michigan or up north you may never know your system is not working as effecient as it could be. 134a also does not work well with condensors listed online as direct bolt in and for 134a for a maverick, stay away from these. If it is a tube and fin style condensor I suggest you dont buy it. Classic auto air sells a universal fit updated modern style condensor which is what you need. Here are my findings between the two condesors. Readings were taken before and after the condensor. Condensors were sealed to radiator for full air flow listed in degrees Out side Temp 84 70-77 direct bolt on 134a condensor (original tube and fin style) intake temp was 133' output 123' this gave inside a/c vent temp 68' Water hose was then used to cool condensor a/c vent temp went to 54' now I switched condensors Classics auto air universal fit condensor intake 130' output 98' inside a/c vent temp 50' (daytime 84' outside) night time re-measured, outside temp 77' inside a/c vent temp 41' Its interesting to note that the new style condensor was colder with only air than the original style was with cold running water running through it. 134a will work with stock condensors however the new modern design from classic auto air will blow colder and save you gas and money even if your system is working fine now. Each tube on the new condensors have 6 indiviual ports, the design is completely different and makes all the difference in the world. As for chargning, these reading were with 1.68 pounds of 134a. Charging in pounds should be anywhere from 1.5 to 2.0..... Charging to 2.5 seems to cool just as well but was causing compressor stalling during startups. I found it interesting that originally installing 134a into a fresh system with not vacuuming the system vs. having the system vacuum made no difference in cooling. Numbers listed above with both condensors were with no prior vacuum. Tomorrow I am having a new dryer put on and having the system vacuumed. Its always a must to have the system vacuumed out, I only mentioned it to save anyone money who thinks their new system may not be cooling due to water or air in the system. Other issues with cooling on our cars can be the outside/recirculate vent, may not be working. Testing is easy to do. Turn the blower to off and turn the vents to MAX-A/C. Drive the car to about 50 mph and feel the vents to see if you have air flow. If you do then you have a leak. My car was fairly sticky on the vent movement, sometimes the diaphram had enough power to close the vent sometimes it didnt. I locked mine down with wire. I have never once used fresh air vents on any car, but if you happen to like it then they do have adjustments which may help, they are located all the way on the right side of the car down by where the kickpanel speakers would be installed. All you need is a phillips screwdriver. Hope some of this info helps anyone converting their system or has problems getting their system working properly during hot weather. Ben
Brains, I'm in the process of ordering an under hood conversion kit from Classic Air. They tested my evaporator -- it checked out OK. Had settled on the original design repro condenser but I think I'll change to the universal. Thanks for the Very helpful info. Jim
They told me the same thing about my condensor at first. As long as the fins are there and it holds pressure its considered good. Which is what the salesman told me too. However their Tech guy in the service department quit. He does however come in 2 or 3 times a month as this is who they give all the classic conversions and hard cases too. I was lucky enough to meet with him. He explained that unless I have a full points concourse competition to not use a tube and fin design. He claimed the condensor is the most important by far in the a/c system, and its even more important when it comes to 134a. 134a is 3 times smaller in molecules and requires a completely different condensor style. My system is already together so I can not post what the ports look like but I will try and explain it. Normal condensors are just a round tube and hollow inside. They are basically just like metal fuel line bent in back and forth. When you look inside the new modern style 134a condensors the tubes are flat and wider, it almost looks the size of a note book ruler. However the difference is that the tubes are not hollow. They are solid tubes then machined with 6 to 8 .040 inch ports for the coolent to flow through. So each fin running across actually has 6 small ports, this allows the smaller molecule 134a to have more surface area to cool. The larger the ports are on the condensor the less the 134a cools. So if you think of the difference of .040" ports vs. 3/8 tubing, it makes sence why normal condensors do not cool as well. You may be able to make a normal condensor work, which im sure many people have. Climate, location, humitidy all play a roll. But as the tech explained you can take any a/c system using a tube and fin and switch out the condensor to make it more efficent, which means using less gas and colder temps.
Oh, this is soooo confusing... My uncle lives around the corner from Busch Gardens, I'm sure he has some R12. 43rd street??
Maybe that`s why my air isn`t as cold as it was on R12! You learn something new everyday! I will think about getting one of those when my cash flow is better.
here are some universal condensers and a picture if the difference in flow for 134a. http://www.ackits.com/c/Parallel/Parallel+Flow+Condensers+-+Aluminum.html
Very interesting and informative. I plan on getting this sys in my Comet, hopefully this year. Im going like Brainsboy. I don't want a half-a$$ workin system if Im going thru the trouble and expense of doing it. Thanks for that info. I had talked to the folks at Classic but not ready to do the upgrade just yet.
The kind of condenser you are looking for is called "parallel flow". There's a decent selection of them here: http://www.ackits.com/c/Parallel/Parallel+Flow+Condensers+-+Aluminum.html I *think* 14x24 fits in Mavericks, but I can't remember right now. They are not a direct bolt-in replacement, and you'll need to make brackets and hoses. You can use this type of condenser with r-12 or 1-134a, but its a must with r-134a if you are expecting any kind of A/C performance, especially in a Mav because the condenser area is rather small. You'll want to maximize the airflow through the condenser which means sealing between the condenser and the radiator and using a fan shroud. I would also always vacuum the system down as well since the air left in there will cause the head pressure (high pressure side) to be higher, which will reduce performance. I ended up staying with r-12 because I wanted maximum performance from my A/C...but that's me.
While I don't dispute a different design condenser might work better, I've got to disagree with the statement that the old compressors don't work as well with R 134A. My semi, a 2002 International 9900i, came from the factory with a york style compressor running 134A that does just fine. It actually cools two areas, the front cab and the 72" sleeper area so well, you have to run it on low fan most days, unless the temps are close to 100 degrees. The newer rotary style compressers are lighter and may be more efficeient, but the old york still does a good job.
Wish this thread had come a couple of days earlier -- just ordered a repro Mav condenser. I'm trying to change the order. Does anyone know what parallel flow condenser fits well in the Mav?
I agree that the York style compressor works fine. I'm quite happy with mine even though it's enormous and heavy. (Get the aluminum one if you can, much lighter) As for the condenser, I concur with everybody else on that. I run a parallel flow condenser and it works great.
I wanted to know if anyone could help me out...I have checked all the wires/connections/fuse sizes and amperage ratings yet the fuse for the A/c keeps blowing. I can actually have the a/c on and what the solder poor out of the fuse ends from it getting so HOT. Is this from the compressor going out (maybe) and pulling too many amps, or is this from the fan pulling too many amps and causing the fuse to blow? Thanks in advance guys/gals!
30 amp fuse or 15? I had that problem when I first installed my AC. Found out non-AC cars had a 15 amp fuse, AC had 30.
