Powerglide Posted May 2, 2011 Share Posted May 2, 2011 In all fairness...I posted this exact same question on another board. Forgive me if you are offended. The remanufactured SWP123 a/c compressor in my 76 280Z has developed a significant leak at the front seal. The compressor has been on the car and in service for 4 or 5 years. I can get a NEW SWP123 compressor. But in certain circles it is said that the MJ167 is a better/more efficient unit. Any consensus on this? Can you back it up with the facts? I'v only found the SWP123 availible NEW. The MJ167 seems only to be availible remanufactured. NEW is almost always better than reman. But in this case----I'd appreciate some guidance. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted May 2, 2011 Share Posted May 2, 2011 Good Question, Though the MJ167 may be compatible and work well, but it doesn't do you much good to change things that you knew worked before. If the SWP123 worked well for you, then why change models to something unknown? If you swap to a new pump thats rated higher than the other components then don't you risk other parts of the system? Perhaps. I can't tell you how well one would work over the other since I've only used mine which is the SWP123. The bigger thing to consider is since you're cracking open the system, just be sure all the appopriate steps to refill the repaired system are taken, especially the part about evacuating all the old oil and replacing with new. Quote Link to comment Share on other sites More sharing options...
Powerglide Posted May 3, 2011 Author Share Posted May 3, 2011 That's probably good advice. I ordered the NEW SWP123 compressor today. Will replace the drier also. When the reman unit was installed 5 years ago, I replaced the evaporator, the expansion valve, the condensor, the drier and the high pressure switch. The system was flushed, and a vacuum was drawn for 45 minutes. The system will produce wonderful 40 degree air on high fan on a 90 degree day here in Florida. The compressor is also quiet. Unfortunately, it requires a 12oz. can of R12 ($25 a pop) every 4 to 6 weeks. The leak is almost entirely at the front compressor seal. Although there is some leakage at the drier as well... In the past, I could top off once a year...but the leak has gotten worse over the last 8 months or so. I really don't have a choice---hence the new compressor. I CANNOT live without a/c in south Florida. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted May 3, 2011 Share Posted May 3, 2011 yeah, you've got the humidity. You might look into what it'll take to upgrade to 134a refrigderant. Call each manufacturer and ask if either compressor is compatable. Now I don't know that much about AC Systems, but I do know that the newer refridgerant is cheaper not to mention supposed to be better for the environ. Er Sorry just noted you already bought the SWP123, so just check to see if that's usable with 134a. I don't think there's any rubber seals in the rest of the S30 system. gotta ask tho. The big thing is to make sue you've got the right lubricant in the system for the type of gas you're going to use. R12 uses mineral oil or something, and R134a has to use PAG. If you've already got the condensor, evap and all with R12 and mineral oil, you should stick with it, since cleaning out all the old oil is almost impossible. I was reading something about other gasses like HyChill which might be usable. This might need to be explored much furthor since Hychill is propane/butane and apparently is compatible with any oil. Be careful though since an incompatible oil and gas is apparently what messes up seals, not the wrong gas itself. Quote Link to comment Share on other sites More sharing options...
Powerglide Posted May 3, 2011 Author Share Posted May 3, 2011 Thanks... But R134a is NOT an upgrade in any way shape or form. It's considerably LESS efficient than R12, operates at higher pressures, and tends to leak in older systems. Plus R134a is up to $15 a can. R12 can be bought via for abut $25 a can. So the cost difference isn't too bad. And the environment will be just fine. It's my sweating brow that I really care about! The new compressor will operate with R134a or R12. To your point...it's the oil that doesn't mix well. This whole thing is particularly aggravating because the old/current compressor gives 40 degree air on HOT days on full fan speed. It just won't hold a complete charge for more than a month. Thanks again! Quote Link to comment Share on other sites More sharing options...
cgsheen Posted May 6, 2011 Share Posted May 6, 2011 (edited) 40 degree air??? I converted my stock system to R-134a when I completed the turbo swap. I'd be dying if it only blew 40 here in Phoenix! I get temps in the low 20's (F)... (I've actually measured it as low as 9 degrees - my son's '76 280 blew 5 degrees after we converted it from R-12 to 134a...) It's hotter than 90 here but we don't have any humidity. I have no problem with using R-12 if that floats your boat (best refrigerant they ever made for these things), but you can make R-134a work just fine. 2 cans cost me about 20 bucks - no reason for me to fuss with R-12... Condenser runs hotter, but we close up the gaps around it and the radiator to get the best air-flow through them that we can. Nissan has always used a good sized condenser - I've never had any problems converting Z's, 240SX's, and etc... Mine has never overheated the cooling system, even when it's 115+ here in Arizona. Edited May 6, 2011 by cgsheen Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted May 6, 2011 Share Posted May 6, 2011 CGSheen, hey could you detail how you went about converting to 134a? Did you have to swap out a lot of parts due to the old mineral oil from the R12? Quote Link to comment Share on other sites More sharing options...
cgsheen Posted May 7, 2011 Share Posted May 7, 2011 CGSheen, hey could you detail how you went about converting to 134a? Did you have to swap out a lot of parts due to the old mineral oil from the R12? No, most of the oil accumulates in the compressor itself and the accumulator (receiver/dryer). The oil in the rest of the system generally isn't enough to be concerned about. Get as much oil out of the compressor as you can and replace it with a like amount of R-134a compatible oil. They always suggest that you replace the accumulator with a new one - I didn't on my Z, but it's a very good idea. That's the main filter (and "dryer") for the system, so it protects everything else. They make a conversion product that has a small amount of oil, acid neutralizers, conditioners, plus a small charge of R-134a to carry all that stuff into the system. It's a good idea to use it on a older system that you're converting. You use slightly less R-134a than the system specified charge of R-12. I never charge by specific amounts though, I go by pressures and performance. If you have leaks, find and fix them. Vacuum down the system, -30psi for 30 minutes, to remove as many condensables as can be removed. I'm overly careful about NOT introducing any "air" back into the system when I'm charging, so I bleed my gauge set and hoses before (while) attaching them. Just let a whisper of refrigerant escape through the hose(s) while you're connecting them. You'll get better results the first time out if you charge when everything is nice and WARM... If it's 90-100 here (remember, no humidity here... It's a DRY heat!) I shoot for center vent temps in the mid-to-low 20's with a suction side pressure in the low 20's psi. Suction side pressure will start out much higher, and fall into place when the refrigerant level / performance gets near the "sweet spot"... Quote Link to comment Share on other sites More sharing options...
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