strotter Posted July 6, 2005 Share Posted July 6, 2005 After a year of fighting and futzing, I have finally got a functioning a/c system in my '72! I have managed to marry the compressor spec'd for my donor car (a Harrison from a Firebird), an original aftermarket evaporator (one of those little guys that fits in the passenger footwell), a condenser off a 280, as well as a couple of custom hoses and relays and wires, into a functioning system. At last, my evil plan begins to come together... The original plan was that Dan (the Man, Cover Of A Magazine Guy, walking-talking advertisement for Flat-Top-Haircuts and Fiberglass Fender Flares) Juday, who's an a/c professional, was gonna help me get the thing operating last summer; but my assembly was so sad-a$$ed I had to take it home in shame and redo just about the whole thing. By the time I had it assembled correctly (I think), it was autumn and who needs a/c in the autumn? While I was at it, I installed a CRX fan dug out of the local Pick-n'-Pull. So this year it was Job One: I went out and bought some gauges and lubricant and hoses and a little vacuum pump and whatnot, did some research on this board and elsewhere, and had at. At first the system wouldn't hold vacuum; then it held vacuum better but not perfectly; then there was a problem with the evaporator; and so on and so on. Finally, after replacing the original donor-car compressor, it held vacuum overnight. Huzzah! This morning, I hooked up my hoses, drew vacuum for half-an-hour, popped on a can of '134 and went to town. At first, after feeding in the first can of refrigerant, the compressor didn't cycle on, and I thought I had a new problem: but a little more research confirmed that there was a low-pressure switch that needed a minimum of pressure to engage the compressor, so I reasoned that more refrigerant would allow it to enable the clutch so I pressed on. Sure enough, just as I began introducing the second can of coolant, the compressor began to cycle on and off - too quickly at first, but as the low-side pressure began to come up, the cycling was slower and slower. After the second can was entirely introduced, I checked the outlet temperature: 50 degrees. Not good enough, so I began to introduce the third can ten seconds at a time, recheck the temperature, introduce more, check the temp, so on. After a few iterations the temp had dropped to 44.2 degrees and held constant through another dose of refrigerant. Time to stop. The ultimate test will be this afternoon: 91 degrees and clear. Not high for this area, but warm enough to see if we have enough BTU's to do the job with the windows closed in stop-and-go traffic. Go Scott, you the man! Go Scott, you the man! Hurray Me! Quote Link to comment Share on other sites More sharing options...
Tim240z Posted July 6, 2005 Share Posted July 6, 2005 "I love it when a plan comes together" Quote Link to comment Share on other sites More sharing options...
Phantom Posted July 6, 2005 Share Posted July 6, 2005 I'm impressed! That was quite a saga - and it ended successfully! Congrats! Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted July 6, 2005 Share Posted July 6, 2005 Congratulations!! Now you guys are going to make me want cold air too! Mike Quote Link to comment Share on other sites More sharing options...
Metro Posted July 7, 2005 Share Posted July 7, 2005 Nice job! I'm hoping to cobble something together out of my 280zx parts car soon. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted July 7, 2005 Share Posted July 7, 2005 Way to stick to it and get the results you want. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted July 9, 2005 Share Posted July 9, 2005 my 77 always blows cold air.but systems on early (70 -74)were cobbled up with old piston york compressor.if i was going to to install on older z i would probably order some parts from vintage air-and ditch the old nissan stuff. Quote Link to comment Share on other sites More sharing options...
strotter Posted July 9, 2005 Author Share Posted July 9, 2005 Randy, I *did* ditch the original-type compressor, used one from a later-model GM (a Harrison). I've checked the a/c system with one of those fluorescent lamps w/ glasses, and it's not leaking. So far so good. There are a couple of problems, though. First, I seem to have wired it incorrectly - when the radiator fan comes on, it engages the compressor clutch. So I'll be going over my wiring diagrams again. Second, the vent outlet temperatures have never reached as low as they did the first day - going down the road temps are in the mid-50s F range (on the first day, I was getting mid-40s). Barring leaks, then, maybe there's not enough 134, or maybe too much, or maybe there's water contamination, or maybe particulate contamination or maybe... Also, I need more fan. The CRX fan I installed - which was a big improvement over the original - still isn't enough. I don't want to take as drastic a step as installing an LTD fan (which would be great deal of work to do right), but I will dig around Pick 'n Pull to find something that might be a bit more aggressive. I'm also thinking there may be an "old wire" voltage issue in all this, something I'll check out soon. All in all, I'd say this project is like every other part of a hybrid swap - the basics are fairly simple, but getting things to work *properly* takes a lot of time and effort. Quote Link to comment Share on other sites More sharing options...
speeder Posted July 10, 2005 Share Posted July 10, 2005 All in all, I'd say this project is like every other part of a hybrid swap - the basics are fairly simple, but getting things to work *properly* takes a lot of time and effort. Good job! It's all in the details. Been there, conquered that! With successful conversions to R134 on several old cars, I now know more about A/C (from the school of hard knocks) than I ever wanted to. Don't you just hate those jobs that siphon time and money away from the performance tweeks? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.