1984 Nissan 720 AC Build

[Ejack]

Hello world!

 

Over the past few months, I have been painstakingly putting AC on my Nissan 720 KC 4x4 pickup which was a success!. I'll detail the parts I needed here first:

 

**DISCLAIMER** THIS WAS NOT AN EASY BUILD, REPRODUCE AT YOUR OWN RISK

 

**Photos At Bottom** https://postimg.cc/gallery/6xSQ6qH

 

1995 Nissan Hardbody

-Compressor bracket

-Compressor

-Low pressure line (evaporator->compressor)

-High pressure line (compressor->condenser)

-Condenser

-High pressure line (condenser->evaporator)

-High pressure sensor

-Drier

 

1985 Nissan 720

-Evaporator

-Evaporator box

-AC switch (optional if you want a clean original looking build)

-AC relay

-AC thermo switch (this goes in the evaporator to prevent it from freezing over)

-Evaporator low-side fitting (hack saw required)

 

1999 Honda Civic (don't give me shit for this)

-Condenser

-High pressure line (compressor->condenser)

-High pressure line (condenser->drier)

 

Misc.

-NAPA 9355 V-belt

-HVAC Super Pro https://www.amazon.com/Highside-HS32098-HVAC-Solderless-Bonding/dp/B01LZT77G7/ref=sr_1_1?dchild=1&keywords=hvac+super+pro&qid=1595816127&sr=8-1

-Swage Tool https://www.amazon.com/gp/product/B077RT3D79/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

So, what did I do?

 

PLUMBING

Well, once I had all my parts, the first thing I did was install the compressor. The d21 compressor bracket bolts right onto the z24 block, which made it easy, then I installed the compressor to the bracket. It's a very tight fit between my steering box and my compressor, however, there is no rubbing. From here, I worked my way around the refrigeration cycle. I modified the d21 high pressure line (compressor->condenser) by chopping the old fitting off meant for the hard body condenser and joined my fitting for the Honda condenser. The Honda condenser will fit in between the radiator and the front braces. To accomplish this, pull the radiator towards the engine and slip in the condenser. Take out the hood release and bend down the lever to allow for more room for the condenser. The latch will still be functional, but a little bit stiffer. Mount the condenser in all 4 corners with custom brackets. Next, I modified my high pressure "out" tube for the Honda condenser by completely bending it into a "U", chopping off the end that points towards my drier and fusing my d21 fitting that fits into my d21 drier onto the Honda tube. The drier fitting was scavenged from a hard body condenser I naively bought. From there, I made a small vertical post next to my drier, then hose-clamped the drier to the post to have it mounted and not going anywhere. The high pressure switch goes in the drier. The d21 high pressure hose to the evaporator actually fits super well in the 720 and goes right into the drier via an existing hole under the inner right headlight. The evaporator side of that high pressure tube needs to be swaged (expanded), and a spacer ring should be installed behind the o-ring for it to properly seal.The evaporator core and box went in with no trouble since it was made for that truck, but before it hoes in, you have to modify the low-pressure port by sawing off the old female fitting and fusing a male fitting from a hard body evaporator core. Swage the copper low side tube once the fitting is off, stick in the new fitting, and fuse. Connect the low side tube on the evaporator and then into the compressor after this modification: Cut off 1/3 of the compressor side fitting closest to the engine to avoid hitting that part on the distributor. This didn't sit with me right, but it's on the low side and it holds pressure for me because I doubled up on the seals. Also, drill out the remaining bolt hole on that fitting to allow the hose to pivot away from the steering shaft and avoid rubbing it.

 

Note: For the plumbing fuses, I first tried brazing. After failing miserably, I switched to HVAC pro for my fuses. I also needed a swaging tool to expand the tubing to fit the other tube into it.

 

ELECTRICAL

Good news! My truck came with all the wiring I needed from the factory! Firstly, I put a fuse in my empty AC fuse slot. Next, I made an adapter that connects my AC switch to a 2 prong outlet under my dash. Next, I soldered an adapter that connects a 4 prong outlet under my dash to my AC relay. Next, I found my high side pressure sensor wires in between my washer fluid reservoir and my battery. I extended those 2 wires all the way down to my high side switch on my drier by straddling my factory wire harness. Lastly, I connected my 1 wire on my compressor to the factory red compressor wire  hiding under my ignition coil.

 

PHILOSOPHY

Why did I do this instead of taking the parts off a 720 to put AC on my truck? 720 AC parts are very hard to source and I was not able to find any OEM parts online. Honda civic and Nissan d21 parts are by contrast, super cheap, and easy to source, so if any of this breaks, it wont be the end of the world and I can get replacement parts. Also, it was a hell of a lot cheaper than a Vintage Air system.

 

CONCLUSION

This is a gross oversimplification of what I have done, so if anyone is interested in reproducing this project, let me know and I may be willing to take better and more photos as well as a more detailed description of what exactly I did. You guys helped me out with a fuel problem a few months back, do I thought I would do this write-up as reciprocity. Enjoy!

 

PICTURES

 

 

free image hosting site

 

[NC85ST]

Nice. How long have you been running this setup? Does your interior fan push enough air?

[powderfinger]

Nice job, interior on your truck is in really good condition as well. If you could find a truck bed in good condition you would have you a really nice 720. There is a possibility in the future that I will have a spare bed that I could maybe part with. I actually have one in excellent shape now but not willing to part with it at this moment. It's the newer style from an 85 model though. 

[Ejack]

19 hours ago, NC85ST said:

Nice. How long have you been running this setup? Does your interior fan push enough air?

 

It's been finished for a little over a week. It's hard to tell how well it works because it has consistently been 90-95 degrees and sunny since I've had it. In these conditions, it's not ice cold inside like on a new car mainly because I have no tint and I don't think my windows are polarized, but it's kept me from sweating on my way to work which is what I was after. Once the sun goes down though, It's amazingly cold and a few nights ago I was driving around and it actually kept cycling on and off because the evaporator was getting close to freezing! I'm really impressed with my tiny Honda condenser and ancient Nissan evaporator. The stock fan is really loud on the 3 and 4 setting, but the airflow is there if you want it.

[Ejack]

1 hour ago, powderfinger said:

Nice job, interior on your truck is in really good condition as well. If you could find a truck bed in good condition you would have you a really nice 720. There is a possibility in the future that I will have a spare bed that I could maybe part with. I actually have one in excellent shape now but not willing to part with it at this moment. It's the newer style from an 85 model though. 

 

The interior is great, and the frame is solid, but the body is pretty rough. Not quite ready to undertake that yet, but I'll definitely let you know if I want that bed. Thanks!

[powderfinger]

Two King Cab 720 truck beds just showed up on Facebook Marketplace in Raleigh a couple of hours ago pretty cheap. They are not in the best of shape but better than yours. 🙂

 

[johnsontf]

On 7/28/2020 at 4:43 PM, powderfinger said:

Two King Cab 720 truck beds just showed up on Facebook Marketplace in Raleigh a couple of hours ago pretty cheap. They are not in the best of shape but better than yours. 🙂

 

A long shot but do you still have a spare tailgate? I am looking and close-ish to Raleigh.