- Category: PROJECTS
- Published: Wednesday, 14 January 2009 17:11
- Hits: 19555
There are three major components required for air conditioning your Austin Healey, the first is the compressor mounting, the second is the choice of an aftermarket A/C unit, and the third is the condenser selection. This may be an over simplification, but if you don't get these right the system could be problematic (read, a failure).
I used the combination A/C & Gen. bracket from Bret Blades (Two Blades), the A/C unit from Vintage Air, and a custom condenser from Classic Auto Air. The rest of the installation I custom fabricated. I've seen simpler approaches than mine, and I find no fault with those, but since I was not retrofitting this system into a completed car I had the opportunity to optimize areas that would not be easily accessable in an assembled car. My goal was to integrate the heating and air conditioning system in a manner which might have been a high-end factory approach, I wanted the interior of the car to retain a "period" look, so I tried to incorporate design cues consistent with the era. Even if you are installing A/C in an assembled car, you may find a few nuggets in my approach. If your car is down to the chassis, what I've done could certainly be cloned.
I'm going to break the A/C installation description into two categories: A) under hood elements and, B) in car components.
A) First, let's talk about the "under hood elements." The items you need to address are 1) mounting of the compressor, 2) compressor selection, 3) drier selection and mount, 4) condensor, 5) firewall considerations, and 6) A/C and heater hoses.
Item 1, mounting of the compressor: This one is relatively easy to handle. If you contact Bret Blades (Bret Blades link) and acquire one of his compressor mounts you're most, if not all, of the way there. The bracket replaces the side plate on the right hand side (generator side) of the AH 6 cylinder engine. In fact, it is designed for hanging both an alternator and a/c compressor. I suppose it's possible to adapt your generator to the bracket but I wanted an alternator, so this combination worked well for me. The compressor mounting is arguably one of the most critical elements of the conversion and, yet, with Bret's brackets it becomes one of the easiest elements. The clearances and belt alignment issues are such that I can't even imagine trying to do this from scratch. Bret's design has evolved, and I would strongly recommend not trying to reinvent the wheel on this part. I did, however find a couple of improvements I wanted to make in the structure and function. I added a gusset to the main bracket that holds the alternator and compressor in place. Bret said he hasn't had any trouble with them, but I like things super strong if they are going to hold critical elements of the running apparatus in position....and, at the early build stage, it is a pretty trivial effort to add a gusset to the support arm, assuming you have access to a welder and a bit of 1/2" square tubing (Pic #1). I then took the gusseted plate and support arm to a machinest to have a "fly" cut done to ensure it was still level after the welding and thereby ensuring a leak free attachment to the side of the engine (Pic #2). I also chose to make the job a bit more complex by making my own tensioner arms. I've never had a high confidence level with friction tensioners as used on most older cars alternators and compressors...and, because of cost considerations, this is understandably the approach that Bret took with these brackets. If you love over engineered items, as I do, the fix for the friction tensioner brackets is to make heim joint connections that will never loosen....the belts may stretch but the heim joints can be easily dialed up to compensate. This sounds a bit easier than it is since this means designing standoffs (Pic #3) to get the needed distance to provide attachment points for the heim joints....however, this is all doable with a bit of scape steel and some ingenuity. I designed the heim joints with attachment shafts that are threaded opposite directions on opposing ends, so the center bolt adjusts both sides in or out without disconnecting a heim joint from its attachment point. So with the strengthened mounting plate and revised heim joint tensioners, I mounted up the alternator and compressor (Pic #4, 5).
Item 2, compressor selection: The Bret Blade's mount is designed for a Sanden 508 compressor. Assuming that it is a given that you will be using the currently legal 134a type Sanden, the only real choices are between a "top exit" or "rear exit" model compressor. The "top exit" refers to the placement of the attachment points for the A/C lines that you will be plumbing into the compressor....they exit pointing up. Bret told me that the top exit model was the usual choice because it is easier to plumb in an assembled car. So, I first mounted up a top exit model (Pic #6) and saw that, since my car wasn't assembled, I could make a much tighter packaging of A/C lines with the rear exit model (Pic #7). Fortunatley, the compressor provider (a hot rod shop) that I was working with was more than willing to make this exchange for me since I had not plumbed in or activated the compressor ...... you may want to keep this in mind if you are unsure of which compressor you will be installing and possibly work this out with your compressor provider before you go too far. The "rear exit" model places the attachment points for the A/C lines lower in the compressor, i.e. coming straight out the back rather than out of the top. (Note that I think Bret is correct that the top exit would be easier in an assembled car.) The fitting of the A/C lines to the rear exit model required extremely precise measurement. I bought all the fittings and hoses, did a mock up of everything and then took them to the A/C shop to have the fittings permanently installed using their special tool to crimp the beadlock fittings to the hose. When I say "mock up" I mean that I cut and fit the hoses to the A/C fittings, so I would know exactly what route I wanted them to take, how long they would be, and at what angle the fittings needed to be attached to the hoses. Whether you use a rear exit or a top exit compressor I would suggest mocking up the lines rather than just measuring them since it is difficult to assess the amount of bend that is appropriate for the various size lines and the angle of the fitting attachments. For me, the big benefit of a rear exit compressor is that with careful placement of the lines, they are almost hidden from view.
Item 3, drier selection and mount: When selecting a drier you can get a basic one or one with some key safety features. Actually, the driers are the same, but one model has fittings for either a binary or a trinary switch. The binary switch shuts the compressor off if the system has either excessive pressure or low pressure. In a high pressure situation, the switch will turn the compressor back on when/if the pressure comes down to acceptable levels. The low pressure condition will need action such as recharging the system and possibly fixing a leak. The trinary switch is similar in function to the binary switch but also incorporates a electric fan engagement feature....so when the A/C is turned on the electric fan comes on. I chose the binary switch because I have an electronic fuel injection computer (ECU) which knows when the A/C has been turned on and turns on the electric fan. In any case, adding one of the safety switches is good insurance against system failure, and if you have an electric fan it would be best to use the trinary switch to engage the fan when the compressor is turned on. Placement of the drier will depend largely on where you want to, or can, run the A/C lines from the condenser to the drier to the firewall. I put mine on the backside of the right side front wheel well (Pic #8). That position gives me access from underneath the car and makes it just about impossible to see from the engine compartment.
Item 4, condenser: This can be tough. Getting a large enough condenser that is in the flow of fresh air to function optimally is the goal. I have heard that some early Mustang condensers and Mazda condsensers will fit, but I can't verify how/if they fit the way I wanted one to fit. After some checking, I decided that a custom condenser was going to be needed to satisfy my mounting and plumbing goals....i.e. keeping the plumbing low, tightly packaged, and maximizing the available radiator space. Since I haven't yet reinstalled my body and subjected the A/C system to real world demands, I can't verify that I have provided the best condenser solution to my A/C system needs. That said, this is how I got a condenser that does meet my packaging requirements. After some searching, I found Classic Auto Air Manufacturing in Tampa, FL. There may be others, but these folks will custom build you a condenser to your specifications (Classic Auto Air link). The beauty of this, of course, is that not only can you get the maximum size that will fit your Austin Healey, but you can get the connection points to exit exactly where you want them to optimize your A/C plumbing. I worked with Curtis at Classic Auto Air to place the order (Pic #9 is a copy of the drawing I faxed to Curtis to initiate the order).....Tampa is the manufacturing site so call there and not the Texas location. Note that I specified "do not paint" on the condenser order because it is normal procedure for them to paint the condensers black, and my radiator is aluminum so I wanted them to match. The size I settled on is 16" high by 14" wide, and 1" wide with outlets on the right side with the lowest one at 5 1/2" from the bottom (Pic #9). The cost of the special order custom made aluminum condenser was just over $300, which I felt was a reasonable price for a no compromise condenser. Once you have the condenser in hand you are faced with an even more daunting task....figuring out how to mount it. That may not have been quite as challenging if I had not decided that to maximize cooling I wanted the help of an electric fan. My logic went like this.....Austin Healey's cooling ability in its stock condition is questionable, that is if you like to drive your car in the summer's heat. Then if you put a condenser in front of the radiator, you are going to suboptimize the already marginal radiators effectiveness since you are placing an obstruction in its path. So, I upgraded to an aluminum radiator from Cape International, installed a stainless steel flex fan with a fan shroud, and added a Maradyne electric fan thats function is managed by a SPAL controller (The SPAL controller does not come with the fan; it was purchased separately. The controller will vary the speed of the fan based on the temperature of the engine coolant. If you use a trinary drier safety switch, it can be used to turn on the fan when the A/C compressor is turned on, overriding the SPAL controller. I used a Maradyne M123K reversible fan, this is a 12" fan, set up as a pusher.). Hopefully I have covered all the bases to provide an engine that is free of overheating issues......time will tell. Now back to the question of how to mount up the condenser while making accommodations for an electric fan. Since the condenser is custom sized to the radiator, it fits very nicely into the space available. I suspect it could be attached to the radiator and dropped into place without affecting the cross brace......BUT, I can't verify this since I never really tried this approach. Instead, I fabricated brackets that are pop riveted to the condenser and bolted to brackets that I made to attach to existing structure. For the lower mounts I used the attachment points that also hold the lower radiator mounts, and for the top I made brackets that attach to the radiator support arms. This took some time but worked out well. (Pic #10, 11, 12) If your plan is to replicate this please note that in Pic #10 the mount turns out (away from the condenser) and on Pic #12 the mount turns in (toward the condenser), this was done to maximize the necessary clearances. The advantages of this mounting arrangement are that it makes the condenser more easily removeable and keeps the condenser about 1" away from the radiator which I hope facilitates cool airflow. However, the cross brace is certainly an issue with this approach and an even bigger issue if you want to add an electric fan in front of the radiator/condenser. The problem is exacerbated by the steering linkage cross shaft which is going to move rearward when you turn a corner (I didn't immediately fall to this problem since the car was on jack stands with the wheels pointed straight ahead). The solution for all these complexities was to make a custom cross brace to replace the original. I use the stock upper connection points but used 1/2" square tubing to fabricate a removeable cross brace that allows the electric fan to be accessed if servicing becomes a need, and it attaches in the original locations. Pictures do a better job of explaining resultant configuration (Pic #13). The steering linkage clears, and the fan can be removed (albeit not a half hour job).
Item 5, firewall considerations: How and where you plumb your A/C lines through the firewall will depend in large part on whether you are retrofitting a cooling system into an existing car or if you are doing a ground up build. It will also be influenced by whether you are just adding an A/C unit (under-dash unit) or if your intent is to replace your entire heating, cooling, and defroster system (in-dash). I planned to replaced the whole thing. So at this point, if not before, you need to select the unit you intend to install. This may seem like a strange point to bring this up, but until now the issues having to do with the under hood elements will be the same regardless of your planned evaporator. I will address some of the options in greater detail in the "in car" Project section. I am using a Vintage Air Gen-II Mini heat/cool/defrost model (66005 Series H/C/D). If you use a different manufacture's system or a different Vintage Air unit your choice may well influence a different plumbing placement than the one I used. You will need to decide exactly where you are going to mount the evaporator unit inside the car. That placement will provde some natural requirements for the firewall plumbing. I mounted my evaporator before I cut any holes in the firewall. I will address what I did to satisfy the model I selected. Since my installation was a part of a total rebuild I had the luxury, if you can call it that, of putting the lines anywhere I wanted....up to a point (Pic #14). The elimination of the stock heater input duct, which is a 4" duct, provides one natural avenue for the heater lines, and for the A/C lines I used the space normally blanked out for a left hand drive car (on a right hand drive car the steering column passes through this space). I liked keeping the heater and cooling lines separate to avoid a cluttered look, and I liked putting the A/C lines down low to keep them somewhat hidden. In both cases I used aluminum bulkhead plates which use O-ring seals and give a nice clean professional look. I chose to refinish the bulkhead plates in a black wrinkle powder coating finish simply because I thought it kept the firewall looking a bit more "period". There are many different styles, configurations, and finishes of bulkhead connections. To ensure a solid foundation for the bulkheads I welded 1/4" steel plates into these areas.....a lighter gauge would work but I had the 1/4" plate so I used it. Some builders prefer to use firewall pass throughs on the heater lines (this eliminates 4 fittings with potential leaks).....pass throughs simply provide a protected area for putting your heater lines through the firewall. I've used both and have never had a problem with O-ring seals so decided to go with them because they provide a nice finished look, they are consistent with the A/C lines, and they allow a convenient disconnect if you have an service requirements which would prompt you to remove your heater hoses.
Item 6, A/C and heater hoses: The plumbing of your A/C system is not trivial, but if you include it in your under hood planning from the start it can all come together nicely. Ultimately it will depend on many of the things I've already talked about, i.e. compressor choice (top exit or rear exit), drier placement, condenser choice (where do the connections exit), and selection of firewall location for the lines to go through into the passenger compartment. I chose to use rubber hoses with beadlock fittings, but stainless steel lines are another option. They are certainly a durable long term solution to your hose requirements, but I decided against them purely on aesthetics. I felt the SS lines look a bit too high tech for the overall feel that I'm wanting to convey. Keeping in mind that some of these hoses are #10's, be aware that they don't have the shortest turning radius. I would advise having some of the hose types that you intend to use in-hand when you are planning your plumbing installation strategy. The hose into and out of the drier is a #6, so it is reasonably flexible which gives you some latitude in its placement. Also, the rubber hoses "grow" about 1/4" per end when they are crimped onto beadlock fittings. This isn't a big deal on long hoses, but on short hoses with critical tolerances this can be the difference between fitting or not fitting....it caused me to have to redo a few hoses before I got it to my satisfaction. Since I am a half hour drive from the hot rod shop that was crimping my lines to the beadlock fittings, I ended up adding quite a few hours drive time.....a word to the wise. I'm including a number of pictures circling the plumbed area so you can get a complete 360 deg. perspective on it (Pic #15-20). Notice from the driver side (lefthand drive car) the A/C plumbling is just about hidden, and it will be even more hidden when I reinstall the front shroud (Pic #18). One last note on heater hoses, I replaced the original copper heater return line with a stainless steel version that I fabricated. Rather than have it terminate in its original location, I wrapped it around the back of the engine, so I could terminate it much closer to the firewall bulkhead junction, giving it just a bit cleaner look, Pic #18 gives a good view of it .
B) Now let's move to the in car components. I will break the cabin portion of the project into 4 categories, 1) selection of the evaporator, 2) mounting of the evaporator, 3) in car plumbing, and 4) ducting.
Item 1, the selection of the evaporator: As I have already touched upon, you will need to decide if you are going to just add a cooling system to your Healey, meaning you are leaving your stock heater/defroster system in place, or if you plan to replace the stock heater box with a full function unit that has a heater, cooling, and defroster system in one package. I have seen a some nice add-on cooling systems that I thought looked really good. In the 60's most A/C systems that were added to cars were the under dash stand alone unit style....in fact, in that time period many OEM systems were under dash hang ons, i.e. Mustangs, Cameros, etc. So in my mind, this approach looks very "period" correct. If you are shopping around you will probably want to check out a number of manufacturer's products.....just to list a few, there are Vintage Air, Hot Rod Air, Old Air Products, and Classic Auto Air. Bret Blades has been pleased with the Old Air Products and one of their under dash cooling models is shown on his website. As stated earlier, I decided to replace my entire heater/cooling/defroster system, and I selected a Vintage Air Gen-II Mini heat/cool/defrost model (66005 Series H/C/D). I settled on this model because, at the time, it was the most compact full function unit I could find (Pic #1 and 2)....today there may be other choices, so I would suggest investigating what is available before placing your order. Having said that, I am extremely happy with the size, function, and quality of the Gen-II Mini unit. Once I narrowed it down to what I thought was my choice, I made a cardboard box matching the dimensions of the unit. I then worked with that box to see if it would fit where I wanted it. Vintage Air even makes mock-up units....these are basically shells of the real thing, so you can see exactly what space considerations you are dealing with. The hot rod shop that I was working with didn't have one of these mock-up units to loan me, and rather than buy one myself, I just went with the cardboard box I'd made. After validating the fit, I placed my order. Interestingly, the real unit actually gave me a bit more room than my cardboard box mock-up. I suspect this may always be the case since the dimensions stated are the outside extremes of the unit and the actual unit isn't at the outside extreme at every point in the housing. When choosing an evaporator unit, whether you are going for a cooling unit or a full heat/cool/defrost system, in addition to size and function pay particular attention to where the plumbing connections are for the various units. I found that if the plumbing connections exited in the lower right it worked best for me. Yours may be different if you have selected different firewall pass through locations. The point is, think through the whole package, i.e. evaporator placement, plumbing, both in the cabin and in the engine compartment, and firewall pass through locations. The better you visualize the whole package, the more cohesive the whole package will look. One last thought on evaporator units. Check out the controls that manage these systems. If you get a single cooling under dash unit this is most likely a mute point since they will generally have them attached to the unit. But, if you are optioning for a full function system some of the control panels are more adaptable to our Healeys than others. I went with Vintage Airs standard controls since I was going to custom mount them in my center console. If I were doing it now, I would get a Gen-II Streamline panel that is black anodized....however, that wasn't available at the time. The size isn't much different on the two panels but the Gen-II Streamline uses more advance technology which appeals to me.
Item 2, mounting the evaporator: So now that you have selected an evaporator and have it sitting on your garage floor, how are you going to mount it? If you chose a single cooling under dash unit, I can't help you with the mounting. But, if you went with a full function unit this may be of some help to you. As I evaluated my Gen-II Mini evaporator and the Austin Healey firewall area where the unit would reside, I decided that my best approach was an independent mounting structure that I could bolt into the Healey. With that objective, I designed an exoskeleton that would wrap around the evaporator providing the evaporator good support and relatively easy installation (Pic #3). The objective is to have the exoskeleton mounting bracket be a permanent part of the Healey substructure and making the evaporator removeable for servicing if it's ever necessary (let's hope it isn't necessary, but I like to work on the assumption that if I make it removeable I won't need to. Of course the opposite is most assuredly true, if I don't make provisions for servicing a part it will absolutely require it!!!) (Pic #4,5,6,7,8). The exoskeleton, made out of 1/2" square tubing, is both compact and robust. The 2 nuts attaching the evaporator to the upper exoskeleton frame are welded in, so a person working alone can hold the evaporator in place and thread the bolts into place. Then attach the U loop support (these attachment nuts are also welded in place) and thread in the 3rd support bolt to the evaporator. It had more trial fittings than I care to recall, but in the end it was worth the effort as it fits like a glove, the windshield wipers clear, the ducting for the defrosters and A/C all clear. The mounting frame bolts through the stock AH fresh air duct that passes from the driver side to the passenger side and to two tabs at the top. The mounting frame has a front "U" loop that supports the front of the evaporator. As mentioned at the onset, this mounting system was specifically designed around my Vintage Air Gen-II Mini evaporator, but I suspect variations of it would work for many full function units. Pic #9 shows the evaporator mounted in place. I could have left it at that, albeit with some provision for the center A/C outlet, and mounted the control panel on the dash. However, since in my world "too much is not enough," I decided that this new structure provided me a good opportunity to design an integrated center console for the middle A/C outlet, the control panel for the new H/C/D system, and a place for my extra gauges. I won't go into the build details but will provide a picture of the final configuration (Pic #10). You will notice in Pic #10 that the package tray has been trimmed to fit around the fan.
Item 3, in car plumbing: Plumbing the heating and cooling system presents some unique challenges in an Austin Healey. The issue is, naturally, one of space. First let's look at the heating connections. Conventional wisdom has it that you run rubber heater hoses from the evaporator to the firewall bulkheads. It didn't take too much evaluation to realize that using that approach was going to conflict with my goal of keeping everything compact. The heater lines require quite a bit of space to make corners without kinking. What to do?? I talked to a hot rod shop that builds cars to see if they had any suggestions. They had a fantastic solution.....use rigid copper pipes just like you have in your house. Copper pipes allow you to keep everything very compact, and you can make 90 degree corners in an extremely short space. Your local hardware store has all the fixins to put this together. Once you have cut and fit all the copper lines you will find that sweating the pipes and keeping all the angles intact is quite a challenge. However, patience will pay off in a nice tight package (Pic #11). I used heater hose for the connections, which also keeps a bit of flex in the lines for movement. The pressures that these lines will be subjected to are about 1/3 of your household water pressure, so as long as you do a good job assembling this it is significantly understressed and should last forever. Make sure you are careful to install the heater valve in the correct direction on the supply side line......the valve is designed to flow in one direction. The cooling lines are no less challenging to keep compact, particularly the #10 line. Taking the heater line idea, I got the parts for the #10 line, cut and fit to suit, then took it to a professional welder to weld up (I have a MIG welder that I couldn't live without, but I go to a pro for the really critical elements). This gave me a tidy #10 line to fit my needs (Pic #12). For the #6 line I took a more conventional approach and used regular beadlock fittings, standard A/C lines, and had the fittings crimped on. This is a shade longer than I would have prefered but since it's a small line it lays up tight against the fresh air passage and still allows the fresh air flap to open. When installing the cooling lines with O-rings be sure to use the recommended oil and be very careful not to nick them......you don't want any leaks. One last heads-up, make sure you can get a wrench on all the fittings before you do the final install of the evaporator. I have one line that was much easier to start before I put the evaporator in its mount. As I mentioned in the last section, the package tray has to be trimmed to fit around the fan attached to the evaporator (Pic #13). In addition to that modification, I saw a need to put a barrier between the heater lines you see in Pic #11 & 12 and hands groping in the back recesses of the package tray.....and since I was doing that, it seemed like I could add a few other things to the package tray. So, now the "package tray" has been modified for the following purposes: 1) clearance for the fan, 2) a barrier/heatshield, 3) two power outlets, 4) mounting of the passenger A/C duct, 5) location for the front right speaker, and 6) location for the radio head (the actual radio resides in the back of the car) (Pic #13,14,15)......granted there isn't much space left for "packages." Since I never found the package tray terribly useful for much other than loosing little things in the back, the "tray" is now a very functional element in the interior make-up.
Item 4, ducting: The in car ducting can be extremely simple....or you can approach the blank canvas of the interior as an opportunity to get innovative. Keeping in mind that my goal was to integrate the system in a fashion that might have been installed in a high end factory system of the day......I suspect that you may have guessed which path I took. If you have opted for a single cooling unit the ducting is integral to the unit. If, however, you have a full function unit you need to decide where and how to run the ducts. I'll share the approach I took on my Vintage Air Gen-II Mini full function system. First the outlets originating in the evaporator. I have used regular Home Depot black plastic 90 deg. angle fittings from the plumbing department for the left and right cooling outlets. The only problem with them is that they are round and the evaporator outlets are "D" shaped. To reshape the H.D fittings, you've got to heat them up to reform them to fit. I've used two approaches to get that done...... our oven got them nice and soft for forming (use heavy gloves) but be careful you don't get them to hot or they will loose all their shape.....I've also used a hand held heat gun I got from Harbor Freight for about $15 and formed them to fit. I like the heat gun method the best because it allows a more precise application of heat, but either work. The center duct was an optional item from Vintage Air part no. 60500-UVA, it does a 180 deg. turn and runs the center outlet down the front (Pic #16). The defroster outlets were handled with two Vintage Air items heated and formed to fit. The trick on all the 90 deg. outlets is to get them pointed at exactly the best angle to optimize your under shroud room, and miss the windshield wipers....it's tight but it will all fit. Once I had them all properly located I drilled small locating holes in each of them, put in sheet metal screws, then put a permanent sealer on them....followed up by a wrap of electical tape for good measure. Secondly, following mounting the evaporator, I ran my passenger side cooling duct forward to the dash and then ran it down the back side of the dash. This keeps it out of sight and gets it placed for the far right outlet which is attached to the package tray (Pic #17.1, 17.2). The driver side cooling duct takes a more conventional path across the top of the shroud to meet up with the driver side louver (outlet) (Pic #18). There are many options for the louvers and louver brackets. The air conditioner manufacturers, like Vinatage Air and the others I mentioned at the onset of this paper, all sell a myriad of sizes, shapes, and styles. Since I wanted a polished round rim, to coordinate with the instruments, I went with a Billet Specialties product (some of the pictures show a round louver with a black plastic rim, these were just used during the build and were replaced by the polished aluminum rim louvers when I was done). There are black plastic mounts for these, but I decided I wanted metal mounts to more accurately replicate the build practices of the day (except for small parts, plastic wasn't very widely used in the interiors in the early 60's). So I fabricated my own. You can find other pictures of them done, but this is how they looked during fabrication (Pic #19). I made a front plate using 16 gauge steel, put multiple cuts on the edge of the plate and rolled the edge back to create a rounded corner. Then I took a 3" exhaust pipe, sliced the exhaust pipe, welded it to the front plate and trimmed the edge ....then I finished rolling and welding the front plate....just a little at a time. I then used angle iron to put mounting plates on them..... in Pic #19, the one on the right has the mounting flange welded on while the one on the left doesn't yet have the flanges. Note that the height of the mounting plate is critical because it is determined by the radius of the 90 deg. curve on the feeder fitting, see Pic #20. This is particularly true on the passenger side mount which mates up with the bottom of the package tray, I used this side as the baseline height and made both the same. I followed up the basic fabrication with some finish work. I could not use regular body filler because I planned on getting them powder coated with a black wrinkle finish and body filler can not stand up to the high temperature baking that powder coating requires. The filler I did use was a Devcon product, which is a titanium filler that can take the heat of powder coating....but be forewarned it's expensive. The center louver is the last of the three typical cooling outlets. This one can be simply a matter of matching up a suitable style louver to the center ducting, or you can use the mounting bracketery to fabricate any number of things you imagination can think up. For me, I decided to make a center console that would hold the controls for the H/C/D system, the center louvers, and some additional gauges. The idea was simple enough, but the fabrication presented some real challenges. After much thought, the center console is removeable, it has slots that fit into pressure tabs on the top mounting bracket and is attached with 2 screws on the lower back. All the electrical connections are plugged. The really tricky part was coming up with a way to connect the center louver to the center cooling duct on the evaporator....and make it removeable. The solution was a flexible silicone coupler that the hot rodders use in underhood connections for turbochargers and the like. The coupler is attached to the backside of the louver on the center console using a permanent sealer. It slips into the vertical duct on the evaporator. While the connection is just a slip on fit, with careful construction the fit is quite positive and leak free. (Pic #21, 22, 23) The installation trick is to align the center console with the pressure tabs and the coupler....once they are lined up it snaps into place and is held by the two screws inserted into the captured nuts on the back of the console. A final picture of the completed H/C/D system. (Pic #24) I've charged the system and everything is functioning well. Interestingly, the idle speed drops only about 50 RPM when the compressor is engaged.....a testimony to the torque of the big Healey 6 engine. In fact, the idle drop is so trivial that I don't feel a need to adjust the idle speed up to compensate. The next step in the rebuild is to reinstall the body.
This project paper originally posted on March 2009