nismofiend Posted September 17, 2006 Share Posted September 17, 2006 For backround purposes, 1979 Datsun 280zx NA A/C from the factory, don't know if it's been converted or not but going by the fittings, no. The question is this, since I've had the car the compressor has been locked up and unturnable by hand . I assumed that being so old it finally gave out and froze, today I decided that I can do without a/c since I don't want to pay for a new compressor and started removing the dead weight. I got some lines off, the condensor, the accumulator, etc and when I came to the compressor I grabbed it for leverage and realized that the clutch would turn by hand. Without the compressor under pressure it turns smoothly and easily. Does anyone know if this means that it's actually good? Or does it just turn because there is no pressure in the system, could too much or too little R12 have caused it to freeze up? I'd just like to know if the a/c system is still good or trash because I'd hate to get rid of this stuff if all I need is a retrofit kit but, I'd also hate to go out and buy the stuff only to have it freeze up again under pressure. Quote Link to comment Share on other sites More sharing options...
X64v Posted September 18, 2006 Share Posted September 18, 2006 Did you turn the pulley where the belt sits, or the actual front of the clutch that's directly bolted to the compressor? I ask because reguardless of whether the compressor is frozen or not, the pulley should turn fine. It's when the blue wire gets a +12v source that the clutch engauges and the pulley will be connected to the compressor. Quote Link to comment Share on other sites More sharing options...
nismofiend Posted September 18, 2006 Author Share Posted September 18, 2006 Both the pulley and the clutch spin freely, smoothly, and individually so far I've been getting a 50/50 opinion on this, some think it will freeze up again once I pressurize the system while others think the compressor is good. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted September 18, 2006 Share Posted September 18, 2006 You can test the compressor in hand by applying 12v to the compressor lead and ground to the compressor body. That will engage the clutch. If you can rotate the compressor while the 12v is applied then the compressor is not frozen and possibly is good (could still have shot seals). I'm parting out a '77 with a fully charged a/c and the compressor is fine. I believe the compressors are the same. Someone chime in if that is not the case. If interested then PM me and we'll work out something on the cheap. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted September 18, 2006 Share Posted September 18, 2006 ....I'm parting out a '77 with a fully charged a/c and the compressor is fine. I believe the compressors are the same. Someone chime in if that is not the case.... OK, I’ll chime... The 280ZX compressors are different from the earlier (1974-78) compressors. The ZX compressors have a larger displacement, require less re-circulating oil and the inlet and outlet ports are reversed when compared to the earlier ones. More info: There are two types of ZX AC compressors, an early one and the later one. Difference being the width of the pulley groove. Early ZX compressors use the wide belt like the 1974-78 compressors and the later ZX compressors changed over to a (more modern) narrow belt. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted September 18, 2006 Share Posted September 18, 2006 nismofiend: here's another clue... when you took the lines off and the accumulator, was there a bunch of black dust in the lines ect.? Somewhere in the system is a filter, often where the line goes into the evaporator. I don't know where it is on the zcar. But if this filter is clogged or there is a lot of black dust in the system, this is the compressor seal material, and that is an indication that the compressor is in rough shape. I just noticed you're in florida... it gets hot, you sure you won't miss the air? Quote Link to comment Share on other sites More sharing options...
nismofiend Posted September 18, 2006 Author Share Posted September 18, 2006 We never had a car with a/c growing up and I've never owned a car with a/c so Im used to it, so long as I have a/c in the house and it's cranked down Im happy. When I removed the lines, the receiver/dryer, condenser and the compressor no black dust or sludge came out, some greyish bluish oily substance did come out though although it seemed to be clean and in good shape. Last night it was starting to get dark and I didn't have a definite answer on whether or not the compressor could be good so I decided that since most of the stuff was already off I would finish taking it off and set it aside if I needed it. Well florida decided to dump some rain on us so now the stuff has been out in the rain for a few hours, doesn't bother me much because this car is already slow as balls I'd rather ditch as much stuff as possible and keep it comfortable. I guess if I really really want a comfort car I'll buy something as a daily driver, maybe with an auto or something. Thanks for all the helps guy, I know when I come here I'll receive only the best help. Quote Link to comment Share on other sites More sharing options...
defrag010 Posted September 18, 2006 Share Posted September 18, 2006 going off on a tangent, does the stock 280ZX a/c system use the ECU to control it in any way? Say, for example I take my stock ECU out in lieu of a megasquirt.. if all of my stock a/c components are still there, will the a/c still cycle right? Quote Link to comment Share on other sites More sharing options...
PUSHER Posted September 18, 2006 Share Posted September 18, 2006 Seems like the only thing electical is the clutch switch, which wouldn't need the ecu. Everything else is mechanical, not sure if there is some oddball sensor needed for the ecu that it wont work without, hopefully someone can give a 100% yes or no. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted September 18, 2006 Share Posted September 18, 2006 ....does the stock 280ZX a/c system use the ECU to control it in any way? .... No. The ZX ECU only controls the FI. AC system is completely separate. Quote Link to comment Share on other sites More sharing options...
defrag010 Posted September 18, 2006 Share Posted September 18, 2006 thanks! Quote Link to comment Share on other sites More sharing options...
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