Adding A/C....let's discuss it

[Carbuilder]

I'm hoping this will be a useful place to talk about adding A/C. This is not to tell me why I shouldn't do it and/or why it won't work. This is for those that have maybe considered it, and could add to what I currently know.

Let me also add that my car is modified; 347ci engine, different tranny and rear end, different front suspension, different seats, etc. So keeping anything stock is not an issue. I also have a completely different wiring harness with the fuse box where the glove compartment would be, so I can't go into that area of the dash.

I've added a Vintage Air system to my Factory Five 818C (kit car) so know a little about it. I've also read many times how people have added other makes of A/C, not been happy with it, switched to Vintage Air, and it worked great. It could be that systems that are smaller are smaller for a reason....they don't work as well.

The various Vintage Air systems I've looked at are fairly small when installed in a "normal" car. The interior of the Tiger is pretty small and there isn't much room. Here are the 4 different systems I've considered.

1) The totally hidden type that mounts up inside the dash. This is what I put in my 818C. Even the smallest unit is likely too large to fit. The unit does have heat/defrost and A/C, so some of the existing stuff under the dash can be removed. I don't think it helps to remove the heater core, as that area is remote from the under-dash area and doesn't free up space where the A/C evaporator would mount. This evaporator is about 19" long, 7 1/2" deep (front to back), and 9" high.

2) The other popular system is what was used in a lot of older cars, especially those that had dealer installed A/C. This is the unit that mounts under the dash. They are available in A/C only, and A/C and heat; no defrost though. I mocked one of these up with a cardboard box and if mounted in the centre of the dash, it doesn't interfere (too much?) with the driver or passenger. But is still is pretty big and a bit of an eye-sore. But it would fit and probably be the easiest way to get A/C. Maybe taking out the current blower motor would allow it to fit up under the dash just a bit. This evaporator is about 16" long, 5 1/4" high, and 12" deep.

3) There is a trunk mounted system. Obviously this would fit well enough. But I don't think that blowing cold air from back there would do much without ducts to bring it forward. Don't really see a good way to do that.

4) There is a vertical stack type unit. It fits under the dash, but extends down to the centre console. This would require the existing blower motor to be removed, probably along with the vents and some of the defrost ducting. Hard to mock this one up without actually removing things, but I'll do a better job of measuring and see what it looks like. This one has heat/defrost and A/C, so anything related to that with the factory stuff can be removed. This evaporator is about 16" long, 9" deep, and 12" high.

What I've found when searching is reference to someone that installed it and the very fuzzy pictures looked like it was under the dash. There was a Tiger for sale recently that apparently had A/C and it was not visible so must have been up under the dash. It would be nice to get some details from any one that has done it and could add some useful info.

This will be a winter project (what better time to add A/C?) so not something I'm jumping into right now.

What it looks like up under there with now:



Rick

 

[Austin Healer]

I have an Aston Martin DB5 in the shop right now. It has a factory installed A/C system and it is entirely fit behind the rear seat and accessed through the trunk. It has it's own fan motors separate from the heating system under the dash. The drawback with this system is that the outlets are in the rear of the car facing the front of the car. There are no front outlets for the A/C. This works in a saloon (coupe), but wouldn't in a Tiger except with the hardtop fitted.

There was a dealer option A/C unit for the Austin Healey 3000 MK3 (US market only).. It was a complete underdash unit with it's own fan. The Healey has a center console so the unit was installed on the RH side of the dash under the glove box, I believe it had a second, much smaller outlet on the LH side of the dash under the tach (below the wood dash)

I would think, if you found a small enough condenser, you could hide it behind the false floor on the passenger side. Then it would just be a matter of a suitable fan and ducting/outlet system. If the car is equipped with footwell vents, you could remove the RH side vent box and use the area for your fresh air intake for the A/C system. The harder bit would be coming up with room for the evaporator up front, the dryer and compressor. Logically, the compressor would need to be on the passenger side for ease of routing the refrigerant lines to the condenser...

Probably the easiest solution for the compressor would be to mount it where the generator or alternator would normally be, The remote oil filter system would have to be ditched and the 90 degree filter adapter and smaller filter fit and an alternator fit on the LH side of the car.

Personally, I'd recommend using the original cast exhaust manifolds as the heat coming off of headers is nearly 800 degrees (F) , and in any event the headers are too close to the oil filter on cars with the adapter... for my comfort, anyway.

It will be interesting to see what you come up with!

 

[65beam]

My Hagerty agent has a vintage air unit that I believe has the A/C and heat in his MK 1A Tiger. It does eliminate many things behind the dash and he has vents in the center and on the sides under the dash. I'm not sure how he has the condenser mounted but I think it mounted to the upright floor that comes up to the package tray and above the rear axle. I'll probably see it at the Dayton show in a couple weeks so I'll check it out. Tiger Tom had A/C on his Tiger and he mounted a small condenser behind each head light as well as a fan for each one. Ed Eslinger had A/C on his Tiger and the condenser was mounted under the trunk floor and it had an under dash unit. That Tiger is now in Canada. I recently had a discussion with Vintage concerning using the under dash mini A/C in my 69 GT but that another story since it has a three person back seat.. Sunbeam sold a dealer installed A/C unit for them.

 

[Hoghead]

How are you going to drive the compressor?

 

[Carbuilder]

I haven't taken measurements yet, but I think the compressor can go on the left side of the engine. Or, it would be better for running the refrigerant hoses to have the compressor where the alternator is now and move the alternator to the other side. I think the alternator is a little smaller than the compressor.

My brother is restoring an old kit car, a Manta. He just bought an A/C system for it from a guy that does a lot of custom frames for kit cars, and apparently really knows his stuff. The kit he bought has a 12 volt electric compressor. I told him many times that it won't work well. The person that he bought it from has sold many of them, but we can't find anyone with an electric compressor in a car to comment on how well it works. A/C generally takes about 3HP. At 100% efficiency that is about 2237 watts. So with 12 volts, that gives 187 amps. Kind of a lot for an alternator to put out. There are alternators that put out that much, and even more, but I still have my doubts.

The interesting part of his kit is the evaporator. It is made by Old Air Products and seems to be a nice size. It is what I call the vertical stack design and is about 13" wide, 9" deep, 11" high, so a pretty nice size.

The other very important thing is to have a very good condenser. I think people that tuck one in wherever there is some room may have a poorly working A/C system for that reason. It must get a lot of cool airflow for the system to work well. My radiator is about 1 1/2" in front of the water pump pulley. I don't have a mechanical fan, just an electric one in front of the rad. I think moving the rad as far rearward as possible and putting the condenser in front of it (and the fan in front of that) would be the way to go.

I took my Factory Five 818C out for a drive yesterday in the 90F weather with very high humidity. The A/C worked so well I had it on the lowest fan setting and the temp not all the way cool. The evaporator drain was pouring water out!

Rick

 

[Bryan]

How are you going to drive the compressor?

I have a double pulley for a tiger that some modified

 

[Carbuilder]

Oh, how am I going to drive the compressor? Not sure, but I don't think it is a major issue. Of course I rarely think things are until I get started. There is room on the water pump to make a new pulley with another drive in front of the existing one. Also room to make a new main shaft pulley with 2 drives.

 

[Austin Healer]

I haven't taken measurements yet, but I think the compressor can go on the left side of the engine. Or, it would be better for running the refrigerant hoses to have the compressor where the alternator is now and move the alternator to the other side. I think the alternator is a little smaller than the compressor.

My brother is restoring an old kit car, a Manta. He just bought an A/C system for it from a guy that does a lot of custom frames for kit cars, and apparently really knows his stuff. The kit he bought has a 12 volt electric compressor. I told him many times that it won't work well. The person that he bought it from has sold many of them, but we can't find anyone with an electric compressor in a car to comment on how well it works. A/C generally takes about 3HP. At 100% efficiency that is about 2237 watts. So with 12 volts, that gives 187 amps. Kind of a lot for an alternator to put out. There are alternators that put out that much, and even more, but I still have my doubts.

The interesting part of his kit is the evaporator. It is made by Old Air Products and seems to be a nice size. It is what I call the vertical stack design and is about 13" wide, 9" deep, 11" high, so a pretty nice size.

The other very important thing is to have a very good condenser. I think people that tuck one in wherever there is some room may have a poorly working A/C system for that reason. It must get a lot of cool airflow for the system to work well. My radiator is about 1 1/2" in front of the water pump pulley. I don't have a mechanical fan, just an electric one in front of the rad. I think moving the rad as far rearward as possible and putting the condenser in front of it (and the fan in front of that) would be the way to go.

I took my Factory Five 818C out for a drive yesterday in the 90F weather with very high humidity. The A/C worked so well I had it on the lowest fan setting and the temp not all the way cool. The evaporator drain was pouring water out!

Rick

I think it would be a lot easier to route the refrigerant hoses if the compressor took the place of the generator/alternator. in any event, the remote oil filter assy will have to be removed to facilitate the mounting of anything on the LH side of the engine bay.

 

[Carbuilder]

in any event, the remote oil filter assy will have to be removed to facilitate the mounting of anything on the LH side of the engine bay.

Mine already is. The oil filter assy is mounted in front of the drivers side wheel.

 

[Hoghead]

Double "Fairmont" pulley I made for a mates race car to shorten the alternator belt in an attempt to reduce belt whip at high RPM.
As it turns out it has other uses...............

 

[Carbuilder]

Very nice! So does one belt go from the crank to the water pump and then a separate one from the pump to the alternator; 2 short belts instead of one longer one? Or, as you suggest, one belt goes from that pulley to the A/C compressor.

 

[Hoghead]

Very nice! So does one belt go from the crank to the water pump and then a separate one from the pump to the alternator; 2 short belts instead of one longer one? Or, as you suggest, one belt goes from that pulley to the A/C compressor.

Yes that was the routing for the 2 short belt application. I have not done air-con or power steering myself, but would seem another likely application for the 2 sheave pulley

Another mate used this pulley last month to fix an alignment problem with what he thinks is a 54 oz fat balancer, and stock fan and alternator placement

I only have one left, but no reason that I could not make more

 

[Austin Healer]

Another thing to contemplate is the need for a better cooling system. With the evaporator installed in front of the radiator there will be a reduced flow of air, additionally with the A/C in operation, you'll have a new source of heat directly in front of the radiator.

I drove 520 miles over the last 2 days in my Tiger. Yesterday on the way back home the ambient air temp was close to 100 degrees. The car ran at 80 C. even climbing grades (4000 ft. mountain pass) and I hit road construction as well. Pretty sure the only reason I didn't overheat was the exhaust vents in my LAT style hood and the dimpled tubes in the radiator core. Well, I overheated, the car didn't!!

 

[Carbuilder]

The engine cooling is a concern. Mine runs about 200F-210F on a hot day. But it does have a 426HP engine. When I remove it at the end of the season and tone it down (lower compression heads and mild cam) that may help it to run cooler. Also, reading the in-depth article on cooling, I have the electric fan with many curved blades; the one the study shows does not flow air very well. So I'll change that. Also, I don't know what thermostat is in it, but I'll check when the engine comes out. And...wait, there's more....I should fill in the horn holes. So there are many things I can check and improve to help the cooling.

I do have the exhaust vents in my LAT style hood. My hood is all steel, so the person that did the work did an amazing job with that. Though with the area of those vents I can't see them really doing a lot, but every bit helps I suppose.

 

[Austin Healer]

The engine cooling is a concern. Mine runs about 200F-210F on a hot day. But it does have a 426HP engine. When I remove it at the end of the season and tone it down (lower compression heads and mild cam) that may help it to run cooler. Also, reading the in-depth article on cooling, I have the electric fan with many curved blades; the one the study shows does not flow air very well. So I'll change that. Also, I don't know what thermostat is in it, but I'll check when the engine comes out. And...wait, there's more....I should fill in the horn holes. So there are many things I can check and improve to help the cooling.

I do have the exhaust vents in my LAT style hood. My hood is all steel, so the person that did the work did an amazing job with that. Though with the area of those vents I can't see them really doing a lot, but every bit helps I suppose.

Electric fans, or ANY fan for that matter only work when the car is stationary, or below 15MPH. I have the horn blanking plates, a 160 thermostat, a radiator with dimpled tubes (slows down the water), the Canadian LAT fan, an oil cooler (as I have a Mk2) and the LAT hood (mine is also an all steel version). I had someone who also doubted the advantage of the vents. I had a willow tree on the property and the vents had filled with leaves. I fired up the engine and the leaves were immediately blown out of the vents. They work.... I found when I fit the hood, underhood temps dropped almost 20 C. I am running stock cast ex. manifolds. I recently watched an episode of "engine masters" on Motortrend TV... Avg heat radiated off of headers is close to 800 degrees F. Even when ceramic coated or wrapped with the header wrap the temp drop was less than 20 degrees. The problem is not getting air through the radiator, it's getting it out of the engine bay. You do not want to add any additional heat under the hood than can be exhausted,

It's 96 F degrees here today and I just came back from a "spirited drive", indicated temp on the gauge was 80 C. or just above thermostat opening temp. 160F equals 74C.

Another thing to take into account is mixture and timing... the leaner you set the carb and the more advanced the timing is, the hotter the engine is going to run...

 

[Carbuilder]

As I've dropped the engine for some mods (in another thread) figured it was a good time to work on the interior as well.

I pulled the dash and removed the blower motor to see how much room there is for an A/C evaporator.



Not really enough room, so more sacrifices have to be made. The fresh air vent boxes are pretty large so I removed them. I also removed the defroster ducts. I will need to add back in defroster ducts, but I can make some that fit around the A/C unit. I mocked-up a unit the size of the Vintage Air Mini and "installed" it.



Despite how it may look, I think it fits pretty well. I will of course cut out the lower dash supports and add some form of them back in. The actual unit is not exactly a box, so there could be a little extra room here and there. The unit sits about 4" behind the dash and none of my instruments/switches stick out more than 3". I'll push it up as high as I can, still allowing for the vent hoses that connect at the top.

Of course I have no vents for A/C, so I'll add them to the dash. I was going to redo the dash anyways for a couple reasons. One is that despite it looking like wood, it is plastic. Also, since the A/C unit has heat and defrost, I won't need the sliding controls that sit at the top of the dash. I'll remove those and rearrange things to fit in some vents. Probably redo the switches as well since I won't need a blower switch. I'll incorporate the A/C control panel on the dash.



Doing without the fresh air vents is OK. If it is a bit warm I'll use A/C. Fresh air? Open a window.

So things look good at this stage and I'll progress with it.

Oh, not sure if anyone has issue with defrosting the windshield. When I removed the metal ducts below the dash I noticed that the opening is about a 1/16" wide slot. It is almost closed in some areas. Don't know if it got squished a bit at some point but it sure wouldn't put out much air.

Rick

 

[Bryan]

I have a double pulley for a tiger that some modified

anybody need a double pulley - found in boxes of tiger parts- nicely done welding

 

[Bryan]

anybody need a double pulley - found in boxes of tiger parts- nicely done welding

 

[Carbuilder]

Another option.

I can use one of these under-dash units:


Here it is mocked up:



It would protrude about the same as the dash. This is showing it about as far up as it could go, which would be an inch or 2 into the dash. It could be dropped a bit so it fits under the stock dash and still does not interfere much with driver/passenger leg/foot space.

Advantages are that it doesn't need any air hoses run, dash vents put in, or separate control panel; it is all part of the unit. This one is heat and A/C.

The disadvantage is that it doesn't provide any defrost. But I think a small blower fan tucked in there dedicated to defrost piping would be fine. Put it on a separate switch for use only when needed. That would blow air onto the windshield and combined with the heat and A/C unit should defrost the windshield fine. The other disadvantage is that it wouldn't provide any heat to the foot box area. But is that really a concern with a Tiger?

I'm thinking this is the way to go due to the much simpler installation.

Rick

 

[Jon B]

Thank you for doing the R&D! I appreciate anything like this, even though I doubt I'll ever go through the work to add A/C to my own car. Your trun signal switch rebuild is very impressive as well.

-Jon