DIY Front Air Conditioning

[shepherdsond]

[Howesight]

A bit more on the recent work.

Here is the trial fit of the suction line fitting to the compressor after braing on the hose end, but before and clamping the hose end.

Marked the hose and ferrule for orientation:

Lifting the hose up to use my crimper:

Suction line now installed and checking the discharge fitting orientation to decide on placement of the hose end fitting to braze on. Yes, the discharge line has corrosion on it. The factory SVX line has rubber over this area and it appears to have kept water or some other corrosive in that area, causing corrosion.

By the way, aluminum brazing is, so far, a snap. With the one aluminum brazing rod I tries so far, (non-flux core), I needed only propane heat. Let's see if I feel as happy after I do my vacuum leak test - - fingers crossed.

I am awaiting what is supposed to be an incredibly good aluminum brazing product from "Johnson Braze-All", a manufacturer of specialty solders and brazing rods. Here's the link to their website:

http://www.saday.com/what_s_new.html

Here's a link to their video showing their product in use:
http://vimeo.com/50539594
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'86 Syncro Westy SVX

[Howesight]

Still plugging away at this project. This just in:

Spazz Brazer Succeeds Despite Himself:

So - - my "Johnson Braze-All" aluminum brazing rods came in and after a couple brazing fails that necessitated me going out to get replacement fittings for the two I destroyed, I now know the secret to aluminum brazing. Note that this only requires a standard propane torch - -no MAPP gas or oxy-acetylene needed.

My brazing jobs involved seven brazed joints. I decided to save the brazing on the evaporator for last since I couldn't afford to ruin it. The secret you ask? Well let me describe the process and then what I was doing wrong.

First, clean the parts to be brazed in lacquer thinner to remove all traces of oil and then blow dry with compressed air. Then use a toothbrush sized stainless steel brush (get two) to prepare the surfaces which will be brazed. A steel brush will not work. For the interior portion of the braze joint, use your spare stainless brush, but cut it in half width-wise and use your tin snips to shorten the bristles enough to allow it to be inserted into the ID of the braze joint.

Second, don't fret about having a tight dry-fit before brazing - - the brazing rod material can fill rather large gaps and my view as an amateur brazer is that imperfect technique might leave un-brazed gaps in a tight dry-fit, but in a loose fit, the gap between the pieces being brazed together is large enough to allow good flow of the brazing material into the joint.

Third, hold the work pieces in something that will not bleed all the heat out of the pieces being brazed. I put a couple pieces of wood in my vise and clamped coat-hanger wire between the pieces of wood to hold the work pieces in place. The wood does not absorb the heat where the work pieces touch it and the coat hanger wire only absorbs a bit. For straight pieces, placing them vertically on the coat hanger wire worked. For 90 degree fittings, I put a bend in the vertical coat hanger wire plus a second wire to stabilize the outlet of the 90 degree turn.

Fourth: Set up your work piece so that the female part of the joint is on the bottom. This allows the braze rod material to flow by gravity into the joint, making up for poor brazing skills. This also allows you to fill in very large gaps. The braze rod material is far harder than aluminum, so having a lot of it in a joint will not weaken the joint.

Fifth: As you heat the aluminum, at a certain point you will notice the portion of the flame that goes around the tube you are heating will noticeably change colour from bluish to reddish. At that point, you can touch the braze rod to the work to get some flow.

Sixth: Now the secret - - apply most of your heating to the male portion of the joint and less to the exterior of the female portion. This seems to force the molten braze rod to be "sucked" into the joint. Note that good quality rod melts just shy of the temp at which the aluminum itself starts to melt. My mistake was applying too much heat to the exterior of the female portion of the joint, burning through, while the male portion had insufficient heat to melt the braze rod.

So now, a note. Keep all those old AC fittings and pieces of fittings you used to throw away, assuming you have scrapped any AC-equipped cars before. With the brazing rod I used, it's just so easy to make bits and pieces.

I will post a few pics of my ugly, brazed fittings shortly. In the meantime, let me report that after a trial assembly of the whole system and vacuuming it down to 29 inches, it held the vacuum overnight, so my ugly brazing at least did not leak.


Fun With ABS Plastic:

That allowed me to take out the evaporator so I can start fabricating the evaporator box and the fan and ductwork.

Here's the first bit - - getting the fan in place. Below is a standard, new, Vanagon blower fan.

I need to mount the fan and made up these flanges for each side of the fan.

Dry fit before gluing:

The beauty of ABS is it can be formed with heat (carefully) cut with a sabre saw (as here) and "plastic welded" using ABS cement. This is found at any Home Depot. It chemically melts the plastic so it bonds to the piece you are joining. At room temperature, the bond is almost immediate, so you need to be quick and accurate on this. My garage was cold (say 45 degrees F), so I had more "open" time with the glue.


Here's one of the flanges finished and ready to glue to the fan. The small tab is where my mounting bolts will go.

Now a duct-tape assisted dry fit to double check in the fan's intended location. The weather stripping is only there to isolate any fan vibration from the sheet metal the fan will bear against.

And the fan with flanges glued in place and ready to mount (after drilling mounting holes):

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'86 Syncro Westy SVX

[Howesight]

Well, I'm too sick with the latest flu to work on my Westy, so I thought I'd post up some recent pics.

I am using 1/4" ABS sheet plastic to make the evaporator housing. ABS can be heated and set, solvent welded or screwed together. I use all these techniques. I solvent glued these tabs to the bottom of the housing to receive screws. I know fibreglass would likely have been easier, but the resin smell would last forever and a day.

Here's the evaporator core after aluminum brazing on the required fittings for my install.

This is the orifice tube holder with my awful (but leakproof) aluminum brazing.

Here's where things get interesting and I had to get creative. My system will use the vent to the left of the steering wheel, have two centre vents where the radio used to sit, and also use the stock passenger side vent at the far right side of the dash. Since I am using only one fan motor, I am trying to make the most efficient duct system possible. So, to do that for the far left vent, I have to duct chilled air across the top of the Vanagon heater box, to a custom-made 90 degree by 90 degree duct I made from a stock Vanagon piece of ductwork. This view is through the stock radio cutout looking (over the number 1) at the custom duct.

Here are some more views:

- just barely clears the instrument pod.

_ dry fit before solvent welding

This shows a vent duct modified by cutting and turning and gluing with ABS cement:

This shows the modified vent through the ash tray hole. This will be the right hand vent of the two centre vents.

There is no sense in having a front AC system if hot air can still come in through the VW fresh air ducts, so I installed closing flaps that will be operated by a vacuum servo. The flaps are also need for cool-weather de-humidifier operation since I am ducting some (not a lot) of chilled air into the Vanagon air box. Here are some pics of the fresh air closure flaps:

img]https://www.thesamba.com/vw/gallery/pix/1011101.jpg[/img]

I used 9/32 steel dowel, sheet metal, my MIG welder and some POR 15 for rust resistance.

Here's my high-pressure side aluminum brazed solution. It was the last braze I did and the least ugly!

The accumulator fits, but just barely. My knuckles are knackered.

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'86 Syncro Westy SVX

[Howesight]

Well, I have been busy with the DIY front AC project and have great news. I installed my RedTek tonight and got great performance. I heated up the garage and put two electric space heaters in the van to get interior temps to 90 degrees F.

So the long and the short of it:

At 75F ambient outside temp (heated garage), 90F interior temp, I got 38F degrees at the vent outlets and I still have about 60% of my glove box, unlike the Behr unit.

I have had to reconfigure the evaporator from my original plan. The original plan was to use a Vanagon blower fan to force air through the evap. In the end, the space was not sufficient to permit this. The blower fan outlet was right up against the evaporator core, so most of the evaporator area would not get air and only a 2" by 4" area of the evap core would get air from the blower.

The solution was to use a fan on the cold side of the evaporator to suck the air through the evaporator and blow it into a plenum that directs the chilled air to 4 large ducts (one each for the four vent grilles) and two small ducts for my patented Krotch KoolerTM outlets.

So here are some pics:

The 3 pics below show the plenum I made which receives the chilled air from the Toyota 4Runner (1990 to 1995) blower fan. I made 4 large outlets and two small ones. I gave up on ABS as I just could not get the shapes I wanted. I used fibreglass to fabricate this stuff, using modeling plasticine to make a one-time only mold. The long nozzle in the first pic is the duct feeding the far right dash vent.

The 3 pics below show the shroud I made to attach the Toyota fan to the evap box and draw air through the evaporator core.

This pic shows the water drain for the evaporator box:

This pic shows my patent-pending Krotch Kooler vent locations. Keeps the sperms cool and vital.

This pic shows the first iteration of the evaporator which was a blow-through design. As noted above, this approach was abandoned. In the tight spaces of the Vanagon dashboard, it seems, it's better to suck than to blow.

In the pic below, the yella arrow shows the lever arm for the fresh-air block off doors I made. This keeps all the outside air outside when you select that setting. I use the bowden cable that used to operated the fresh-air doors that feed to the ducts in the front doors. Those doors are wired shut.

The red arrow shows the space available for duct hose to supply the Krotch Kooler TM vents (green arrow).

VW actually has a lot of useful bits for ducting. Don't be shy at the pick n pull.

VW defrost hose left. VW main vents hose centre. Right pic is aftermarket AV vent hose. |I don't like it for long distances as it will, I think, reduce air flow compared to a smooth duct. This is also why I spent a lot of time configuring my plenum attached to the toyota blower fan.

The VW vent outlets are easy to modify for tight spaces:

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'86 Syncro Westy SVX

[Howesight]

A few more pics on my progress:

For the DIY guy, silicone is your friend. This shows the evap box with drain lines installed.

Ditto:

Ditto:

The shroud and plenum I built from fibreglass stank of fibreglass resin, so I painted both with POR15 and they do not not smell of anything now. Inside the shroud, I used JB Quick epoxy to glue in small metal plates to accept the machine screws that attach the blower fan housing to the shroud. Here are two pics:

The next two pics show the 4Runner blower fan housing mounted to the shroud. Circled in yellow are the 4 screws that attach the blower fan housing to the shroud using the metal plates.

The plenum looks ugly, but it works. Should have used low gloss paint!

The yellow arrows point to the ducts for the far left (driver's) vent and one fo the two centre vents. The red arrows point to the ducts for the Krotch KoolerTM vents. The duct that swoops around to the right supplies the passenger side vent.

Nice high-side pressure (rad fan on high)and good low side pressure:

40.3 degrees F at the centre vent and (shop/garage at 75F interior at about 85F). Right side vent was at 38.1 degrees F, but the pic did not turn out (damn flash!)

Overall, I am pleased and excited to try this rig out in real hot weather. Bonus: I still have a glove box!

Tonight I install the wiring (no more testing jury-rigged wiring) and the rest of the ducts.
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'86 Syncro Westy SVX

[dobryan]

Great ingenuity!

I'd love to do this.... one of these days.....
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[Howesight]

Thanks, Dobryan. With the new configuration pulling air through the evap instead of a pusher approach, I probably would not need to clock the windshield wiper motor. It also turns out that I did not have to use the Vanagon heater/ventilation box for one of my ducts with this revised evap location and set up.

For anyone wanting to replicate this setup, this means no clocking of the wiper motor is needed and the only mod to the vanagon heater/ventilation box is to install doors to keep out hot ambient air. If all your seals are in good shape, then even that is not required, making this more of a bolt in. I wanted the extra flaps to that I can feed chilled air to the factory vanagon heater/ventilation box in future if I choose. That is still an option with the way I built the plenum.


The major work for me was getting the orientation of the evap box, custom shroud and custom plenum just right to take advantage of the space actually available under the Vanagon dash. No off-the-shelf unit except the Behr unit really does this effectively, so I had to DIY.
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'86 Syncro Westy SVX

[morymob]

When the weather breaks some i'm going to be doing an ac install on my westy. This winter have some variations in mind to get a split sys (1front/1rear). One is to reverse heater core and ac evap location+ vvents to top of dash. There are some small gutsy heaters 3-speed that are easier to locate than the evap. Gotta remove dash for front vent flap seal so sky is the limit.

[Howesight]

Hi Morymob:

Sounds like a plan. I intend to install a small evap in the rear of my Westy later on IF the front system does not cool the rest of the van well enough. My step daughter seldom complains about heat even in desert heat, so it's really up to her.

If I do install one, I think I will get one of the slim aftermarket ones that are 5" high, 14" to 16" wide, and 10" to 12" deep. There seem to be a number of aftermarket evaps available in that size range.

I would install it over the clothes cabinet in the space that is otherwise unused, or else, make a custom cabinet in combination with the rear heater, thus using more space that is otherwise unused.
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'86 Syncro Westy SVX

[morymob]

I looked at some at the show here in january, one like u mentioned seems just right for rear in o-head cabinet facing fwd on the drivers side. I picked up one from a MPV rearsect,pretty gutst, got thr idea from one we owned, can turn on from front or rear , have to sit down and figure wire conn out. Has a on/off sol valve for freon flow when not used that i like.

[wildenbeast]

You are a very brave soul. I really like where you've taken this, especially since I just installed a Behr in-dash AC unit in my van. Two things that may help you;

This is what I used to eliminate the fresh air vents from the heater box;

And, this is what I used for the ducting. It is high flow intake hose available from McMaster, http://www.mcmaster.com/#catalog/115/212/=lshgn9

Good luck with the rest of your project.

Bill
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- Bill, '93 Eurovan Syncro Weekender (2.5 manual ACU)

[MarkWard]

Well documented. I am interested in the auxilary air installed into the side cabinet including the isolation valve mentioned above. We are extremely satisfied with our dash AC. On a cloudy or rainy day, it will freeze you out. On a hot sunny day, after some time, I can feel the AC compressor cycling because the thermostat is detecting too cool of an Evap temp. In the sun, it keeps the two front passengers very comfortable. I think a second evaporator in the rear side closet might really make a difference over all. Thank you
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☮️

[r39o]

[Howesight]

Hey R39

A much-delayed response here. The Behr unit requires you to forego the glove box. My approach saves the glove box. The aftermarket evaporator units mostly use comparatively lower-quality tube-and-fin evaporator cores that are not necessarily easily sourced if the supplier stops stocking them. When I say lower-quality, I am not suggesting that they will or may fail, but only that they absorb less heat for a given physical size of evaporator. If you have lots of space, tube and fin is just fine and easily cleaned if you have a compressor failure. I have space constraints.

Also, using an OEM-style evaporator allows you to go online and get a great price on a quality aftermarket (eg Four Seasons brand here in Canada) evaporator. But mostly, the new high-efficiency design of the evap core I used was the selling point. It's small, but really absorbs a lot of heat! Of course, I will have more to say on this after testing in the 100F temps of our desert country this summer.

I have thought long and hard about an easy solution to converting the stock air handler to use an evaporator core inside it. I am sure there is a solution and that it would be more compact than my approach. But the real difficulty in the Vanagon is in the fresh-air intake. It is located very centrally, whereas all OEM cars and trucks with a fresh air AND recirculating air handler have the fresh air intake on one side, usually feeding an air handler that has both the evaporator and the heater core and ducting doors/vanes that control air flow through or around the heater core. Toyota has the fan blow through the evaporator in a separate evaporator box and then into the air handler. Audi's large cars pull air through the evaporator, into the fan and then through the air handler. All those systems have dimensions that will not fit into the vertical space in the Vanagon.

The aftermarket systems which I have seen installed in Vanagons shown on the Samba and elsewhere did not utilize a fresh-air intake for the heating/defrosting function. Since I drive in both very hot and very cold ambients here in BC, I still needed the fresh-air intake for the cool/cold weather. Hence, a stand-alone AC system was my choice - - for now at least. Now that I have a few AC tools, I am not hesitant to try other things.

I have finished the system now and will post pics and conclusions shortly. The approach I ended up with, using the Toyota 4Runner (1990-1995) blower motor blows HUGE amounts of air. Here's the Toyota blower fan in my install:

Using as many smooth ducts as possible, I suspect, helped a lot with the air flow. I can run the blower with the compressor off, due to the kind of AC thermostat I used, so I can get interior airflow without any compressor drag when only air flow and not cooling is desired.

I was, until I tested it, dreading the possibility that after all my work, the system would just wheeze out a bit of slightly tepid air. No such thing. It's not just awesome, it's AWESOME . Very happy camper here.
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'86 Syncro Westy SVX

[JPrato]

Nice work! I think you have uncovered an important fact with your Toyota fan. I have the Vintage air system in my dash, It makes cold but doesn't move the air like I think it should. I'm going to look into some different fans now that I have seen your work!
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Joe

87 Syncro Tin Top project
84 Westy, 2.5L Subaru power
06 Subaru 2.5 turbo in waiting
46 Cessna 140

[Howesight]

[Howesight]

[Howesight]

Well, project now finished. Here are some interior pics.

The "mini instrument panel" is from a 1990's Audi. That's where the red-lighted 12 cigarette lighter receptacles came from, as well as the seat heater switch. No seat heater is yet installed - - that's for Autumn. On the Vanagon heater controls, I installed the AC on/off switch. The bottom lever now controls my fresh-air/recirculation flaps. The small control panel on the far right has the AC thermostat on top and the 4-speed fan switch on the bottom.

Bonus: I still have a useable glove box with 1/2 to 2/3 of the regular space available.

To the right of the radio is the cubby that holds my USB extension cord. Yep . . . front and rear diff locks and decoupler, all from Darryl at AA Transaxle.

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'86 Syncro Westy SVX

[Howesight]

Well my front AC is now done. It works very well and I am very happy with it. So now I will summarize what I used, what worked and what didn’t work.

1. I used my stock Subaru SVX compressor. It’s a Zexel unit. I have not used the variable-output capability it has, but hope to in future so that the compressor won’t cycle so much. Maybe someone clever with electrics (Crazyvanman?) can help me get that part working later.

2. I used the CCOT (cycling clutch orifice tube) system for robustness and also to allow me to install an auxillary rear evaporator if the front unit fails to adequately cool the rear of my westy.

3. A lesson learned: The accumulator used in a CCOT system is very bulky and if I was not mulling over a rear evaportor being added later, I would have used a TXV (thermal expansion valve) system for tighter packaging. On a dual evaporator system, the secondary evaporator almost always uses a TXV, with the front (main) evaporator using a CCOT approach.

4. I am very pleased with the Nostalgic Air parallel-flow condenser. I got part the 16" by 24" unit. Fits well.

5. I used #12, #8 and # 6 AC hose throughout, no hardline except factory ends. If I did it again, I would consider using aluminum for some of the long runs. I fished the hose through holes I drilled in the chassis bulkheads to keep the hoses up high and out of harm’s way, since this is a Syncro and I do drive through some rough stuff (like sagebrush, rocky areqas, etc.) On a 2WD, I would not go through the chassis bulkheads with the hoses.

6. The evaporator is for an Audi A4. It’s just the right size to fit in the limited space available. I would use it again.

7. The blower fan is from a 1990-1995 Toyota 4runner as is the 4-speed resistor that comes with this unit. (I did re-locate the resistor for packaging reasons.) This blower fan and the installation pulling chilled air from the evaporator instead of blowing through it, was the single most important choice in making this system work. This is a powerful blower.

8. I made a convoluted duct through the Vanagon air distribution box to feed the left side outlet of the two centre outlets I installed in my dash. The right centre duct is fed directly from the plenum I made from fibreglass. If I had to do this again, I would not modify the Vanagon airbox in this way and would use one large duct with a splitter to feed the two centre ducts.

9. I am very happy with fresh-air/recirculation flap system I installed. Keeping the hot air out of the van in summer really depends on this.

10. I never did connect the AC plenum to the Vanagon air box, although this is still possible on my setup. I just can’t imagine needing it. The stock Vanagon air box has always done a great job of defrosting my windows in cool/wet and cold/wet conditions, so I won’t need the dehumidifying function in cool or cold weather.

11. I tried to use finishing parts that either were or looked like they were VW parts. So, I used an extra rear-heater switch I had to hold the blower fan switch and the AC thermostat. I also installed the AC on/off switch on the main heater controls. I got some Audi bits that look like they might be VW bits. Overall, I am happy with this and the function of the various parts.
12. Since my van is a syncro, it already had the heavy duty 450 watt rad fan. It did not, however, have the proper resistor to enable 3 fan speeds. I substituted tha rad fan resistor from the Eurovan.

13. I looked at the wiring diagram for the stock VW AC and essentially replicated that. The stock system has one relay which has two functions, and I used two separate relays to mimic that relay. The Blower fan has its own relay to control fan speed 4 (which is direct connection to 12V). The factory fuse panel allows you to use relay position 5 by adding two wires t the back of the fuse panel, so that part was easy. I did add a separate refrigerant high-pressure switch which switches the rad fan on to medium speed (up from slow speed) when the refrigerant pressure gets to 220 psi. There is also a separate normally-closed relay that disconnects the compressor whenever the rad fan circuit goes to the highewst speed, to reduce condensor heat input into the radiator. This also mimics the VW setup.

14. One complaint: When I switch my AC on, the rad fan comes on at the lowest speed, as expected. My fan, however, is quite noisy, even at low speed. My son's Westy, on low speed, is much quieter. I expect that installing the new fan I just bought will make this quieter.

15. Oh - - I almost forgot to add: I used RedTek as refrigerant, used the Subaru-recommended amount of PAG compressor oil, and added a bit of oil above that to account for the very long hoses in the Vanagon. Except for the compressor, every component in my system was new, so there was no old oil in the system.
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'86 Syncro Westy SVX