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1977 280z AC -- issue # xx of yy


240zadmire

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Hi all,

My AC system is stock or at least what I been told.  Always use R12 and haven't converted to R134 yet.  The fitments on the compressor still R12.  Not like the R134a where one is bigger than the other and sometime caps color coded.

I read online, forums, including this one and seem like people stating that R134a can be run on R12 system provided flush all refrigerant, new fitments, run not as cool as R12, high pressure....

Knowing R12 is no longer available or at least at authorized AC shop.  The dilemma  I have is that I'd like to keep the car as stock as possible.  Which lead to parts hard to find and sometime impossible.

Seem like there is a company have the equivalent to R12 calls Frostycool R12a.  

 

questions below:

- has anyone use this product before on the stock R12 system?

- I need an A/C drier though the fitment of the tube/pipe need to bend a bit to connect to this.  Is this one work well with stock AC? TCW  I also need a high switch.  I suppose unscrew the front bolt on the driver for the high switch.

 

61OPTtSRcWL._AC_SL1500_.jpg

 

Much appreciate

 

 

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I would try harder to find someone that will work on R12 OR just do a conversion to 134a. I don't know much about those R-12a products, but pretty sure most AC shops do not use them either.

If you convert to 134a, you would want to replace everything in the engine bay and flush the EVAP well. I would think a universal fit PF condenser would be better than a flushed OE one. The PF condensers are supposedly more efficient that the tube/fin type that is stock, and from what I have read R134a will need that to operate correctly.

The main problem area IMHO is the condenser it sits out there in harms way taking rock strikes etc...

Also you need to consider what about the compressor? are you replacing it? there is oil in there as well that needs to be considered in a swap. I have the old SWP123 style, its huge and heavy but very durable. Most folks opt for the modern SD style either real Sanden or clones. Pretty sure if you get one new it will come preloaded with pag (non compatible oil with R12, for use with R134a).

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Hi @Dave WM

I don't know the condition.   The car sat since 2004.  I didn't ask the previous owner.  My bad.  though the belt was loosen from the compressor.  Figure it wasn't working for awhile, that why the belt was loosen up.

I strip the car down nut by nut, bolt by bolt to  rebuild the engine.  When I opened the hose/condenser/compressor ... oil/refrigerant still there.  I thought It was dried up but I guess still some left.

I have the SWP123 as well.  Seem to be in decent shape.  It is mounted to the car now.  Wonder how do I check to see if it is still working.

about replacing the whole thing in the engine bay.  that will cost a pretty pennies.

 

regards

 

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too late now, but generally speaking best thing to do is in an unknown would be to see if the compressor is locked up, if not connect up some gauges and see if there is any pressure, if not then pressurize the system with nitrogen and get out the spray bottle with water and soap and see if you can find leaks. If no leaks and it holds the pressure, then try pulling a vacuum and see if it holds. if it does then recharge with R12 (supply it directly to the AC tech for find a shop that will do it, they are around).

As now with it apart I would tend to go with all new parts and plan for a 134a. the thing about that kit is you still need the condenser for the R134a, I would not trust a 43 year old condenser.

It will take some fabrication. there are direct fit condensers but they are the tube/fin style and not PF, I am not sure that would be best with R134a.

replacing everything up front will get you up to about 800-1000 depending on how you go. AC is not cheap.  

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As far as checking the SWP123, you can hand spin it, see if pushes out air. other than that hard to say. If it has been open to the air its likely to have some corrosion inside, not good, unless it had some pressure to keep out the humidity or if it was in a very dry climate.

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the cheap approach would be t hook it all back up tighten all the fittings and do the checkout procedure I outlined above with pressurized air and then the vacuum. My system had a slow leak, replacing the condenser with a NOS one fixed that, a new drier and recharge with R12 , its been 4 yrs at least, still works great.

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Depending on the environment the interior of the car saw (heavy smoker as an example) the evap may be clogged up with tar/dust reducing the ability for the heat transfer to take place. The other issue is if the expansion valve is ok or not. if its bad its NLA. the upside is you can buy brand new evap and it uses a common expansion valve, the bad news is its expensive like over 300$

The only way to know for sure is visual exam of the fins on the back of the evap. Not an easy thing to do. If its plugged up, the sys will not work  right and you will have odd pressure readings.

If the expansion valve is ok, you can clean the evap but again its a pita. would be hard to do with the dash in place, I would pull the dash rather than trying to fish all that stuff out, if possible at all.

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A lot of folks just say F it and decide to go with an after market system. while true you don't have to worry that its going to work, there is a heck of a lot of fabrication so its not exactly easy, and its still expensive.

I would go with plan A reassemble/test/get lucky change drier,pull a vacuum  and recharge with R12

Edited by Dave WM
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All I read is $$$$ and more $$$$$

appreciate everything you said.  I will try least $ first.  Grease elbow is no problem.  Worse case, leave all windows down and the windshield hasn’t install yet.  Might keep it uninstalled.  It’s 95 degree today and I feel great having resolve the fuel light issue thanks to you and other folks 

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yep try the easy 1st always a good idea. I can tell you that with the stock system working its pretty good. here in sunny FL we get days will in to the upper 90's with high humidity. With the rear louvers it will keep up with the heat to provide a comfortable ride. You cant slaughter meat inside but its good enough that I can turn it off max after a while. The key is to keep the car out of sunny parking. with that the heat gets so high that it takes a long time to overcome. It so hot inside that you cant touch the dash. If I park in the shade or come out of the garage its never an issue.

Black vinyl is not the best for keeping cool and the insulation on the headliner is pretty minimal. add to that the dash radiating heat and you are behind the eight ball.

That being said I did a cross country (well 1/2 country) trip and was fine this was in early sept when it was still quite hot.

Edited by Dave WM
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one last thought, when running AC the assumption is its hotter than heck outside. Make sure you engine cooling system is up to snuff, the hot AC condenser is going to make the rad less able to get rid of heat (preheating the already hot air flowing thru the radiator). So make sure the rad is in tip top condition. Same goes for the rest of the cooling system (fan clutch/hoses/belts).

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Look inside the radiator has not of white calcium/scales.  The fins has a few damage probably something was caught in the fan blade.  I drove around the neighbor for half an hour and the temperature gauge's needle is right between 120 and 250.  I figure, probably 180, 190.  I see lot of people put the 3 rows aluminum.  I'm sure it is much better than the stock one but to me, it looks ugly.  I think there is an after market selling for $300 or so.  I'm not there yet.  This AC will take a long time I afraid.  Worse case, there is always outside air ? or use this during traffic jam Modern Hand Fan CB320F  economical and environmental friendly!

   

Edited by 240zadmire
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I used a common cheap aftermarket radiator from OReilly Auto and it worked great.  I had to mess with the mounting brackets, they weren't perfect, but once it was installed it was much better than the old factory radiator.

On the AC, as I understand things, it's the lubricating oil that is the problem with changing refrigerants.  You have to purge the whole system of refrigerant and oil before adding the new stuff.  I knew a guy at an import shop that said he had had good results draining systems and leaving them on a vacuum pump overnight before refilling with new material.  But, the system still has to be leak free for it to work.  If you opened it and didn't hear the whoosh of refrigerant escaping it's probably had moisture inside and corrosion, I'd guess.   Odds are against you.

 

Funny story (now, maybe) - I was looking under the hood of my grandfather's truck many years ago when I was a kid and noticed the sight glass for the AC system.  I started pressing on it to see if it would move while my grandfather was telling me I shouldn't do that, leave it alone, .... then whoosh, I got a blast of refrigerant in the face as I managed to push the sight glass off its seat.  He said he didn't really use it anyway.

Edited by Zed Head
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7 minutes ago, Zed Head said:

 

Funny story (now, maybe) - I was looking under the hood of my grandfather's truck many years ago when I was a kid and noticed the sight glass for the AC system.  I started pressing on it to see if it would move while my grandfather was telling me I shouldn't do that, leave it alone, .... then whoosh, I got a blast of refrigerant in the face as I managed to push the sight glass off its seat.  He said he didn't really use it anyway.

that's the only way to learn sir.  At least for me any way.  Try to use all my senses.  "Curiosity kll the cat"!  Don't get kill though.

 

I was looking at this awhile back.  Looking very good.  Perhaps waiting for winter to get both AC and radiator hoping the new promoted marketing director saw a slow in demand of these items during winter weather and give a huge discount ?

I can wish, can i!

.https://www.oreillyauto.com/detail/b/murray-heat-transfer-4283/cooling---heating-16773/radiator-20386/radiator-11357/02ac48565f9e/murray-heat-transfer-radiator/433634/4459519/1977/nissan/280z?q=radiator&pos=0

 

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I am doing aftermarket air heat and defrost in my 78 this winter and am starting to collect parts now.
So far I have the vintage air gen 2 mini box and the vintage air 24x14 condensor.
I will be going with a sanden style compressor all 134a with EZ clip hoses.

So far my parts list is around 1500 give or take
That is replacing everything in the car. I will be doing all the hoses and fabrication myself.


Sent from my iPhone using Tapatalk

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R12  AIRCO   NO NEED TO REPLACE ANYTHING !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I  just wanted to ad... if R12 airco is no longer serviced and rebuild for R134a is to expensive.. you can now use (since 2012!) R437a(isceon mo49 plus)  (this was R413a isceon mo49)  There is NO need to replace ANY PART !   oil stays the same.. can filled up just before loading the gas. (If neccessary)

Edited by dutchzcarguy
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It might be.  Worth checking.  When the whole issue of the ozone layer and R12 started, some countries banned certain refrigerants and others didn't.  There was and has been a lot of research going on to find new chemistries.  Maybe there is a simple replacement available now that doesn't get much press, because the cars that needed it have all grown old and decrepit.  The market is smaller.

Also, wouldn't be a surprise to find that R12 is now legal in the US, considering the last three years.  Ozone layer?  Just use more sunscreen.  (That's sarcasm, not my real opinion).

https://www.epa.gov/ozone-layer-protection/ozone-depleting-substances

https://www.epa.gov/ozone-layer-protection/international-treaties-and-cooperation-about-protection-stratospheric-ozone

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17 hours ago, Zed Head said:

Worth checking.

Last year i checkt my 300zxtt (as new with 86000km) aircon.. and it got very cold 4,9 C.  (don't know Mr Fahrenheit.. ?  )   It runs after 28 years still on the first filling R12!   (thats because i use it every 4-6 weeks... i run it every 4-6 weeks.  on the road or in storage (in my own heated and isolated garage)  This is very important, the oil keeps the systems connections airtight.  (there are still people who want to save the system by not using it and that gives a LOT of failures! )

For the time it works i don't need a replacement..

17 hours ago, Zed Head said:

Ozone layer? 

Overhere i hear nothing (for years now) about the ozone layer..  is it good now or gone with the wind??
    Also you don't hear anything anymore about the "acid rain" that would destroy our forests..  i guess "they" have other things on theire minds thats more important (read: brings more money!.. )

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I’m an idiot.  Can you please hand hold me and tell me exactly which one is the low pressure and which one is high pressure valves? I cannot correlate the picture with the  actual setup in the car.

1.  is the valve from the compressor to the cabin/firewall is the low pressure and the other is high pressure?

 

2. I bought the fitting and it already has the needles in it.  When I open the caps from the compressor, there is also needle already in them.  Should I remove the needles already in the valves currently on the compressor?

 

i want to pull the vacuum to see if there is any leak without starting the car.

 

regards

 

46B90BCF-2D3F-4428-9AA4-F0EB11C8D927.png

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low side is fire wall to compressor, High side is compressor to condenser in front of the radiator. On the SWP123 the back is the low side, the middle is the high side. you can also look for a D for discharge (high side) and a S for suction (low side) stamped on the case of the compressor.

the hookup to the gauges is you remove the brass screw on caps on the compressor and then you hook up the hoses, they are old style screw on, not the R134 push on. Would need to see your gauges to know what you have. The assumption is you have no R-12 currently as bleeding it into open are is not legal. So assuming its all leaked out you will have no pressure, so after attaching the hoses (gauges should read 0 psi both high side and low side). you hook up the vacuum pump, open both the gauge valves, turn on the pump and you should immediately see a vacuum. the high side does not read neg pressure so just keep watching the low side. You should get to -29 if you have a good pump and no leaks. Once there close off both gauge valves, turn of  the pump, and watch the low side. If it holds you may luck out. if it does not you will need to replace the pump with compressed air or better still nitrogen. open up the valve from the nitrogen then crack open the low side valve on the gauge, assuming you started at zero just allow the pressure to build to about 70psi. Don't go higher, no need for testing for leaks, get some soapy water and spray around the hoses, compressor, drier, any fittings and esp the front of the condenser. look for bubbles to form. Often you will also see oil stains, esp on the condenser that is also a sign of a leak.

 

Edited by Dave WM
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