Air conditioning retrofit


Tony Natoli
WOW... Coming along nicely...

I sure do hope you freshen the paint on the block as well as the exhaust manifold before the final fit. Everything else looks sooooo great!


True Classic
That's the plan

I am just working out how everything will go together at this point. Not sure if I will restore this engine or use my FI converted '79 engine. This is how the '79 turned out.



True Classic

will you accept a check for either????
or visa for both?????
oh, and can I deduct the twenty that you owe me???


Curator of #10105275
When I rebuilt my AC I went to a cleaner mounting

for the GM alternator than the original 79 style one posted in this thread. Here is what I did


True Classic

Beautiful drawing and I am sure the bracket is elegant.

I had Greg unlock this thead as I needed to fix some broken photo links. I took a detour down the K20 road so a lot of what I did for the alternator and compressor are moot at this point, but I still plan to see if I can integrate the Hurricane unit into my X. As I work out the mounting and ducting details I will post more to this thread.


True Classic
Making some progress now!

Well, I finally got back to the AC retrofit part of my build. I must admit that fitting an aftermarket AC system to the X1/9 has been a headscratcher, to say the least.:hmm: Refurbishing a stock AC system as LarryC showed is probably the easier way to go. I just could not source all of the stock parts and bringing home another X donor car if I could find one to strip would push my wife over the edge.

There is quite a bit earlier in this thread showing how I was going to fit this to a stock X1/9 engine with a Delco alternator and all of the brackets that I fabricated for that. Then I wandered over to the dark side with my K20 swap and that is what has been occupying the past year of my free time. Anyway, back to the AC.

Finding the best position for the evaporator unit in the space of the original heater box took a while, then figuring out how to mount it securely to the body was the next challenge. The Hurricane unit was designed to mount to the firewall of a front engine car so it has three mounting nuts in the case on the side of the outlet/inlet tubes. I attached some brackets I made to these points and then also bolted it to both sides of the tunnel.

To hold it down on the console side, I ended up disassembling the whole unit to cut a hole and epoxy a flanged nut at the base of the evaporator.

I chose a spot that lined up with the threaded hole on the tunnel where the fiber optic bulb housing was attached. An angle bracket held it down there. I put a strip of rubber down on the tunnel to eliminate any creaking from vibration.

There are many things that ran through my mind as I was working on this project. I kept thinking about how to incorporate the controls for the unit. There is also the issue of the hole in the cowl below the windshield that normally has the fresh air flap at the top of the heater box. Do I just block off the hole or try to still allow fresh air? The Hurricane unit is strictly a recirculation type unit.

There are a few different control options available for the Hurricane. Unlike the vacuum powered stock X AC system, the Hurricane is all electronic servos. There are rotary controls as well as two different sized slider control modules. When I ordered the system, I picked the large horizontal one as it was a similar size to the stock control area and I thought I could make it work in the stock location. It was too long to fit without interfering with the clock and too short to take up the whole width. So I put it aside for a while and mulled it over while I worked on the evaporator stuff.

I happened to pick up a used stock AC control unit with the push buttons from Greg Smith and started taking it apart.

In comparing it to the original heater slider controls that came on my car, I noted that the base frame that holds the fan speed switch and the sliders is the same for both AC and non-AC. Fiat just left off the two upper sliders and added the button unit. Also the fan switch has three speeds with the AC version, but only two with the non-AC. The Hurricane control also has a three speed fan switch. The only difference is that it also provides power to the system when the fan is switched on so that the AC compressor does not run when the fan is off.

I tried the Fiat switch with the Hurricane fan and it worked just fine. Ok, I thought, maybe I can modify the stock AC controls to run the Hurricane. There are two long sliders with the control unit I bought. One controls the temperature by operating a servo on the hot water intake and one controls the servo that moves the flap between vent and defrost. The non-AC slider faceplate has the middle slider/slot to control the temperature and the top slider/slot to control vent and defrost. Hmm, this is promising.:thumbsup:

I took apart the Hurricane slider control unit and the two sliders are just long rheostats that were a bit shorter than the slots on the non-AC faceplate, but not too much different.

I figured out which way to mount them so that they would control the temperature and defrost/vent correctly and then with some spacers and epoxy, constructed my custom control unit using the stock AC base and fan switch with the non-AC faceplate.

The bottom slider on the AC base normally controls the temperature valve in the stock system, but it controls the fresh air flap in the non-AC car. The cable connection to the slider control is identical. I cut off the flap part of the original heater box, refurbished it and then mounted it in its stock location. I shorted the length of the mounting studs from the cowl and reversed the mounting bracket for the cable coming off of the flap housing to allow more clearance above the Hurricane unit. So now, I will have the ability to open the fresh air flap as usual if I want, or close it for AC or heat. Plus, the dash will look pretty much stock.

I modified a couple of broken stock slider knobs that I had to hold the metal clips from the Hurricane slider control knobs. I didn’t slide the new knobs I have onto the stock lower slider or the fan switch yet as they are such a pain to get off intact, but they should all line up nicely. I was kind of proud of how it all worked out.:woot:

There is a lighted push button on/off switch that was on the right side of the Hurricane control unit. It is just about the same width as the rocker switches in the console, so my plan is to mount that in one of the rocker switch openings, using a blank plate to fill in the space above and below the switch.

The next thing I accomplished was getting the connections for the heater worked out. Unlike the stock X1/9 heater valve, the Hurricane valve unit has two lines in and two out, plus the servo that controls the valve.

I bent the stock metal heater coolant supply tubes to move them more into the center of the tunnel. Also, the tube closest to the frunk sticks up higher than the rear one. I cut that one down so it was the same height as the rear one.

I used short sections of heater hose to connect those two tubes to the appropriate valve tubes. I then needed two 90 degree bends to connect the valve to the Hurricane heater tubes. I went down to the local O’Reilly’s and they let me look at what they had hanging on the wall in back. I found the perfect piece of tubing, Gates #18799. It had two 90’s in it about the right length.

I cut it between the 90’s and it was a pretty nice fit. If I were to do it again, I would have cut it closer to the bend with the short tail so that the top hose was a bit longer, but it all seemed to go together pretty nicely. Of course, once I do the final install, there will be hose clamps.

Also, part of this was plumbing in the drain hose from the Hurricane to the stock opening in the floor pan. I found a nice 90 degree PVC elbow that made a nice connection from the Hurricane to the drain tube. I did have to create an opening in the side of the tunnel for the tube to pass through. Bending the heater coolant supply tubes toward the driver side allows room between the tube and the side of the tunnel for the drain tube to fit.

That’s where I am at for now. The pictures show the unit without the top airflow manifold in place. I couldn’t get it into position with it all together with the fresh air flap housing in place. I was able to attach it afterwards, but left it off to be able to see better to fit the heater connections. The next part will be to fabricate custom connections between the manifold openings and the defrost/vents openings in the dash. Then the AC hoses to the dryer and onto the condenser. Lastly, I have to figure out how to mount the compressor to the K20 engine. The stock location for the AC compressor is not available because of the cross member at the base of the firewall, plus the subframe mounts to two of the mounting holes for the compressor. I have seen pictures of a couple of K20’s that Matt did with the compressor mounted up where the power steering pump was, but I will have to fabricate a custom mounting bracket for that. Piece of cake…..not!
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Old enough to know better
Awesome build, I especially like the thinking around and execution of the controls. Tidy.

Thanks for bringing us along.


True Classic
Thanks for the encouragement

I'll keep plugging away and posting my progress as long as there is interest.


True Classic
Plumbing and duct work progress

As this project progressed, I was really having second thoughts about this aftermarket AC install as I really wanted to keep a stock look to my dashboard. Once I figured out how to mount the slider controls to the stock components to keep a period correct look and to control the fresh air flap, I started to feel a lot better about how it was coming out. Now that I have made more progress, I am actually enjoying the customizing and fabrication of this system.

Once I had the evaporator location set, I put the accelerator pedal back in as I wanted to sort out the modifications needed to connect to the K20A throttle body. I had hoped to be able to get the cable attached to the pedal linkage as it is inaccessible with the evaporator all connected, but I will have to wait to get the engine installed to get the correct length for the cable. Oh well.

Anyway, with the pedal in place, I checked the clearance to the blower housing as that hangs out past the tunnel on the driver’s side. I felt it was too close so I ended up moving the evaporator toward the rear of the car by about another 2 cm which made a huge difference in the clearance for my foot moving on and off the pedal and not getting interference from the blower housing.

I decided to add another mounting nut to the case near one of the console uprights which created a nice solid mounting point near the top of the evaporator. Now I have two solid mounting points on the console side plus the brackets that go from the mounts on the frunk side to the sides of the tunnel.

There is also an adjustable thermostat that allow you to fine tune the temperature of the cold air from the AC side. This is connected by a small tube that is inserted into the fins of the evaporator underneath the air grill on the passenger side and then runs across the top of the unit to the rotary control. I mounted this control up under the dashboard kind of behind where the cigarette lighter is so that it is accessible when needed, but not visible as it is not used that much once you get the temperature dialed in.

The next step was to mount the dryer. Old Air Products has a small one that fit pretty well in the stock location. I added a trinary safety switch and attached it with a strap to the stock mounting points.

I had purchased an aluminum radiator from MWB and the condenser from Nostalgic Air that LarryC recommended in his AC rebuild thread. The nice thing about using the MWB radiator is that the studs that are there to mount the condenser are much longer on the aluminum one than the stock radiator so I only needed to fabricate one custom mounting bracket instead of four like Larry did. I just drilled out three holes on the condenser frame to fit on the studs.

With the radiator/condenser in place, I started working on the hose connections. There is a #6 hose from the bottom of the condenser to the dryer and from the dryer to the expansion valve on the evaporator. There is a #8 hose that goes from the top of the condenser and runs under the car back to the compressor. Due to the location of the connections and the sharp angle to run the lines between the radiator and the body, I will need to use custom bent hard lines. These have been ordered from Old Air. I am also going to make a hard line from the outlet of the dryer through the opening in the frunk wall to the interior and then a hose from there to the evaporator. I’ll take some photos of the radiator/condenser in place once I get the hard lines made.

There is a #10 line that goes from the upper outlet of the evaporator to the compressor. I ran that back down through the tunnel to the engine compartment. I will still need to get the engine in the car and then figure out the compressor mounting before I can finalize the hose layout to it. Here is photo of the AC hoses coming off of the evaporator. Once I have them exactly the lengths I want, then I will get the fittings crimped on.

Now that I had all of the component locations nailed down, it was time to work on making custom duct manifolds to go from the Hurricane to the stock dash and defrost outlets. The non-AC car has a straight duct that goes from the heater box up to the defrost and that is what I had originally planned to adapt. When I picked up the AC push button controls from Greg, I also grabbed the Fiat AC defrost duct that has the vacuum actuator to change from defrost to side vents.

I really didn’t think I would use it since I had no way to control the vacuum actuator. I studied it for a while and then looked at the manifold on the top of the Hurricane that directs the air to the vents or defrost. The door in that manifold is operated by a servomotor that is controlled by one of the slider controls. Hmmm. The nice thing about the stock AC defrost duct is that it has two take offs for the side vents that are positioned correctly to run the duct hoses behind the instrument panel and the glove box. I decided to take the servomotor off of the Hurricane and see if I could use that to control the flap in the stock one. If I can control that one with the servomotor, then I can just block off the defrost openings in the Hurricane and just run all of the air through the horizontal duct openings. The defrost openings are vertical and honestly, there is very little clearance above them to connect hoses or to make some sort of custom manifold.

I took off the vacuum actuator, cut off the elbow on the flap shaft and found that it was only slightly larger than the fitting that attaches the servomotor to the shaft of the Hurricane. A little grinding to whittle down the shaft diameter and it fit. As the clearance to the underside of the dash is tight, I ended up cutting a “notch” in the tube to the driver vent to allow the servomotor to sit horizontally. There is still plenty of room for air to come through.

I will just mount the servomotor to the duct with some silicone sealant. Of course, now I needed to see if the servomotor would rotate the flap correctly with the slider control. I hooked it up to 12v to see how it would work. Naturally it rotated it the wrong way. :wall: I had already epoxied the sliders together so I couldn’t take it apart to flip it, but it wasn’t a big deal to unsolder the wires from each end of the slider and switch them to correct the movement. Now when I move the slider control to DEF, it moves the flap open.

The stock duct has three small stops that keep the door from going past horizontal with the vacuum actuator since it is only open or closed. The servomotor will position it in any position depending on where the slider is. It does move a little past horizontal so I trimmed off the stops so as not to restrict the servomotor. I then added a small strip of ABS plastic to block the excess air flow when the door is all the up in the dash vent position. Fiat designed this flap to allow some air to always flow around the sides of the flap to the defrost vent.

Anyway, that is where I am right now. Once I get the hard lines, I will bend those to finish up the plumbing except at the compressor. I have to fabricate a custom manifold box to take the air from the Hurricane and distribute it to the defrost duct and the center dash vents. I am also going to add another outlet off of the Hurricane to provide floor heat to the passenger side.


'85 and '83
That's a pretty impressive effort! I am more in the "bag of ice and battery operated fan" class.

Well done - can't wait to see the finished product.



True Classic
Duct work and hard lines done!

Hard lines.
The box from Old Air arrived, so I decided to get the hard lines bent and installed. Here are the hard lines formed to connect to the condenser. The bottom 18” size 6 line goes to the dryer, the top 24” size 8 goes under the car and will connect to a hose then back to the compressor.

Here is the connection to the dryer, then a 12” size 6 line through the frunk wall to the interior to connect to the evaporator.

Duct work.
There were two “eyeball” type vents that came with the Old Air duct kit.

I cut off the parts that the flex hose attaches to and drilled a two-inch hole in the side of the Fiat side vent housings. Then I epoxied the hose attachments to the vent housings, added some flex hose and the dash vents are done. I made a couple of block off plates to cover the holes through the cowl area that feed the side dash vents. These were made from a sheet of ABS plastic made for thermo-molding. I bought a package of them to use to make my custom ducts. I cut them to size, drilled some holes for the mounting studs, then heated them with a hot air gun and pressed them to place, using the vents to help form them to the opening area.

I made a couple of right angle brackets so that I could mount the defrost/side vent manifold in the correct location to line up with the defrost vent through the dashboard. Normally it would fit into the Fiat heater/AC box. Next, I tackled the center dash vent. To connect these, I used the stock manifold that connects from the heater box to the center vents. Again, I used the dash with the vent in it to locate where this manifold is supposed to go, then made a bracket to hold in the correct spot without the dash, then fabricated a custom duct to go from the Hurricane to the manifold. I had to modify the manifold first as it won’t fit all the into the original opening because the Hurricane unit is there.

Making the transition duct took a long time, to say the least. That was the worst part of the whole project. Countless times in and out of the car, heating and forming the ABS sheets to create the pieces, then welding them together with ABS cement. First, I got the connection from the Hurricane to the center vent done, then cut in a hole in the top and built the connection to the defrost manifold. Anyway, here are some of photos of the duct. It’s like the Millenium Falcon, it ain’t pretty, but it works.

Here is how the whole thing looks with all of the duct work done.

So at this point I have gone as far as I can until I get the engine into the car and work out the compressor mounting. That will come right after I get the front suspension back on the car and get it off the rotisserie. Yeah!


True Classic
A few more photos

Here is a photo of the evaporator out of the car with the custom duct work and the modified Fiat defrost and vent manifolds attached.

Here is one with the manifolds removed followed by one that shows how I modified the stock center dash vent manifold. I forgot to take a photo of it before I chopped it up. I used some small rubber weatherstripping from Lowe’s to help get a better seal where the manifolds plug into the custom duct on the evaporator.


Last, here is a photo of the whole radiator/condenser in place. I now have the car off of the front rotisserie so I have better access. I also fabricated some mounts under the nose cone to attach the early style grill as I am also doing a Euro bumper conversion using Doug Martin’s exquisite mounting brackets. These had to be done before I mounted the radiator for good as there is no access to play with the position of them with the radiator in place.


True Classic
AC on-off switch

I finished incorporating the AC on-off switch that I removed from the Hurricane slider control panel. I modified a blank switch plate for spacers and mounted it in the switch panel of the console. I got rid of the dimmer rheostat as it didn't seem to do much anyway, and I switched to LEDs for the dash lights.


True Classic
Somehow I didn't pay any attention to this when it was current - I love the work you did custom fitting the new controls into stock panel, etc. and your custom air duct manifold. I identify with the labor involved there - I have done similar fab work for other things used ABS, etc., I bought a plastic weld kit which makes that process easier (if smelly).

Looks like I need to get the Hurricane unit & go back to including AC in my build. I have been vacilitating on this. Since I already have AC and have already done the LArryC Condensor, etc, much of it will be more straightforward. I'm doing a custom dash a' la Clark, so I'll not worry about any of the ducting, etc., until much later.

Thanks for the awesome photo documentation, as always!