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The great 240 AC system information dump + How to improve AC performance

Interesting, didn't run into that issue with my '91. The fittings were in the same spot as the old condenser. I did use a Nissens replacement condenser instead of one pulled from a '93 though.

Is 940422 the part number for the nissens a/c condenser?
 
I'm using 2 cans of Envirosafe refrigerant in my '92 244 DD. It blows 36-38F out of the vents when moving down the freeway when temps are 90F ambient. At a stand still, the vent temps are running around ambient.

This was similar to what I experienced. Most of my commute is spent in stop and go traffic so the lack of cooling at low speeds was less than ideal. 4 years ago I was ripping the AC system out of my 740, now I cant handle no cold air for 20 minutes :rofl:
 
Interesting, didn't run into that issue with my '91. The fittings were in the same spot as the old condenser. I did use a Nissens replacement condenser instead of one pulled from a '93 though.


Two possibilities:
1) My 91 is an SE, which is a bit of an oddball car in a few ways that generally don't matter (different trim pieces and interior "options" as standard). Unlikely, IMO, but maybe there were some slight differences with the A/C system between the SEs and other 91 models. It would be the first time I've seen something on this car deviate from the other 91 cars in any way that wasn't cosmetic, though.

2) The Nissens condenser you bought could be a one-size-fits all. There's only maybe 2 or 3 inches of difference between the location of the fitting on my 91 condenser and the one from the 93, and I was able to wrestle the original line into place. I bet if the Nissens piece splits the difference it'll fit OK with either hard line. That way they only need to make one part that will be a replacement for 93 cars, and an upgrade for 91 & 92s.
 
I just moved the bracket to the other side and used some spacers to get it out of the way of the lines.

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Sanden gang. This one was $160 shipped on ebay.

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Here you can see how much I had to notch my bracket to make the discharge line fit. You can also see the bolt in r134 charge port adapter I put on the suction line. I then had to make a spacer for the rear upper bracket as vishmutzy detailed. Still need to put the rest of my car back together before I can charge it up and try it out.

I bet this Sanden would be a direct bolt in for anyone with a D24 since the compressor that came on those engines has the same style ports.

By the way, does anyone actually understand the TXV adjustment? Everywhere I read about 240 AC it's 2 or 3 turns for r12 and 7 turns out for r134, but I had a spare late 80s HVAC box with what certainly appeared to be the original undisturbed TXV and when I removed it, it was set to 13 turns . IIRC the one in my old wagon was set to 12 turns, dunno if that one was original or not.
 
This was similar to what I experienced. Most of my commute is spent in stop and go traffic so the lack of cooling at low speeds was less than ideal. 4 years ago I was ripping the AC system out of my 740, now I cant handle no cold air for 20 minutes :rofl:

Made a typo in my original post. At low speeds the vent temps are actually around 40F.
 
Too much thinking. Not enough doing.

In my V8 conversion I used the Ford 2000 model year compressor, new aluminum horizonal condenser, new R134a expansion valve, new hoses, rings and dryer. Flushed everything, vacuumed down and filled with Walmart $5 R134a to 30 psi on low side. How's that for a technical spec?

Seven years and 20k miles later still get 46 degrees vent temperature at 83 ambient. Just checked recently. Still setting at 30 psi. That's not in the 30's but 10 degrees below Volvo specs for my '82.

Can you tell me more about the condenser that you used?
Was it a Volvo unit or did you find something else that worked? I read on here about a 1991 Ford Explorer unit possibly fitting in place, but does not use threaded fittings.
 
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I found an ebay unit that fit by dimensions H & V. Probably would have been better off buying about 1 inch smaller horizonal as I had to drill 4 holes to make it fit. About $50. The connections are standard AC fittings. Only the external connections are specific to old/new connectors.
 
Does anyone know if the 1991-1993 evaporator come close to fitting in place of the early evaporator? Maybe with a little trimming and such?
I'm just weighing my options, trying to determine whether I really need to swap my airbox to the late style.
 
Does anyone know if the 1991-1993 evaporator come close to fitting in place of the early evaporator? Maybe with a little trimming and such?
I'm just weighing my options, trying to determine whether I really need to swap my airbox to the late style.

For anyone searching in the future who may be interested in this information, I found dimensions on the Four Seasons website.

OLD evaporator:
P/N: 54603
dimensions: 3 x 8 x 9.5 inches
Link: https://www.4s.com/en/ecatalog?part=54603&type=p&search=s

NEW evaporator:
P/N: 54502
dimensions: 2.8 x 7.25 x 13.5
Link: https://www.4s.com/en/ecatalog?part= 54502&type=p&search=s


The new style evaporator would actually come close to fitting in the old airbox, but the left and right sides of the box would need to be modified as it's 4 inches wider. The lines also interface with the firewall- I am not sure how that would pan out, but I assume you could position the airbox so the lines fit into the firewall, and then complete the modifications to seal up the sides of the airbox. You'd also have to figure out your own expansion valve, as that will no longer be integrated onto the evaporator.

I chose to simply use the early one and hope that it will perform well enough with the GM compressor (LS swap) and large aftermarket condenser. If it does not, then I may get crafty with the airbox so that the new style evaporator will fit.
 
No.

Both the parts store and Walmart have added valves, hoses and meters to make it easy for amateurs' to test and add r134 and the prices for all above just a can of gas makes it a little hard to compare.

Just gas with oil is OK, gas with oil and dye is OK. Gas with a leak-stop is NOT OK.
 
Interesting. I looked at the switch on my 92 and I see no such adjustment screw. It has Volvo part #3537866

I got so much from this thread! I wanted to contribute a little by answering the question above. This is a question I had as well. There is no adjusting screw on the stock pressure switch (at least on my 1992 240). I came across the answer when I got a replacement for my stock pressure switch from the local AutoZone. The switch looks different and requires a new harness connector. But the adjusting screw is there and the part worked just fine for me. I think it is Santech A/C Switch part MT0207. Do not get the Santech switch for the 1993 for your conversion. It is a slightly different port size and won't fit on the 1992 and earlier R12 system dyer/accumulator port. Working pressure for this Santech part MT0207 is noted on the switch. I think it kicks on at about 25psi. I ended up not adjusting it because the AC seems to work just fine as is. My own R12 to R134 project is detailed with lots of photos at https://volvoforums.com/forum/volvo-240-740-940-12/1992-240-ac-compressor-removal-install-107142/
 
Do the expansion valves come pre-turned? Which way do you use the allen wrench to open them the proper amount, right or left?
 
Do the expansion valves come pre-turned? Which way do you use the allen wrench to open them the proper amount, right or left?

Yes they do, but everyone has different opinions/conclusions on what those settings should be if you think about changing it. You'll probably only find 134a versions now anyway.
Dave B
 
Yes they do, but everyone has different opinions/conclusions on what those settings should be if you think about changing it. You'll probably only find 134a versions now anyway.
Dave B

I have an r134a expansion valve type. How did you figure whether to open or close the valve more? Could this cause too high of pressure in the system if done incorrectly?
 
I have an r134a expansion valve type. How did you figure whether to open or close the valve more? Could this cause too high of pressure in the system if done incorrectly?

No. What it could do it create an incorrect expansion of refrigerant gas into the evaporator, which is what causes it to get cold. It needs to be just right to be efficient and the setting is different for R12 or an R12 replacement. No one on TB has ever expressed a clue how that setting should be adjusted if you need to change it for something other than R134a.
 
I need to adjust mine. I put it at 5.5 turns and I only get about 60 out the vent, whether its 70 or 90 degrees out. Something about superheat, stuff I don't understand, etc. I'll probably just set it to 10 or 12 turns next year, or whenever I feel like it. I have a few cans of es12a left so if I don't get adequate cooling after that I'll go r134.
 
I need to adjust mine. I put it at 5.5 turns and I only get about 60 out the vent, whether its 70 or 90 degrees out. Something about superheat, stuff I don't understand, etc. I'll probably just set it to 10 or 12 turns next year, or whenever I feel like it. I have a few cans of es12a left so if I don't get adequate cooling after that I'll go r134.

And so the cycle of trial and error begins. I have a feeling that using a "turns in" or "turns out" method of measurement will ultimately be meaningless. There are a number of manufacturers of TXVs and they probably set them at the factory based on flow or output pressure. One manufacturer's TXV at 5 turns may be very different than another's.
Dave
 
And so the cycle of trial and error begins. I have a feeling that using a "turns in" or "turns out" method of measurement will ultimately be meaningless. There are a number of manufacturers of TXVs and they probably set them at the factory based on flow or output pressure. One manufacturer's TXV at 5 turns may be very different than another's.
Dave

I think the correct way to do it is with low/high pressure readings and evap temp, then some wizard stuff to figure out exactly where it needs to be. And yeah, my cheap reproduction txv probably doesn't behave exactly the same as a 40 year old oem one.

I can't even read my high side anymore, so I'm just gonna guess. In the last page I mentioned that I found what certainly appeared to be a factory undisturbed txv set to 13 turns out. ?\_(ツ)_/?
 
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