LocostUSA.com

http://www.ebay.com/itm/Universal-Evapo ... 0f&vxp=mtr

These are similar to the old under dash ac units from the 60s.

If you only want ac, the cost is about $70.

I've ordered one of these. Fittings are #8 and #10 o-ringed (standard sized aftermarket). I expect the heater will require a shut off valve, either cable or vacuum controlled and a second switch controlling the ac clutch relay.

The only issue is there are no provisions for a ducting (for the defrost vents) or outside air intake (again, for effective defrosting). I'll be making a fiberglass cap to fit over the intakes for an outside air tube and an outlet for a defrost connection and a way to block it.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Nice looking units. Is there any reason that you couldn't buy an A/C only unit and then run hot water through it and use as a heater only?

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Bill H
Winnipeg, MB, Canada

Using the A/C evaporator core? You might run into problems with the small tubes not passing enough water which translates into not enough heat.

John

I suggest using an MG heater if you don't want to tackle a total diy using yard fan and core or fitting a small oem core to a straight ac unit.

The MG units are cheap and parts are available. Choke cables can be used for control of temp door and a coolant flow valve. You may be able to get the MG heater under the dash on the passenger side. The spitfire heater is more compact and made to fit inside the dash.

On a custom diy, off and on is as simple as controlling coolant flow and fitting a fan doesn't need a molded scroll housing to work, just a couple curved baffles and a hole for an inlet. The temp control door is just a long door the size of the core, hinged toward the fan and next to the core, controlling how much air bypasses the core.

All the airflow would flow through the evaporator and it would simply be off or on, with temp control provided by the heater door.

I considered the cost of a second hand evaporator, expansion valve or orifice tube, heater core, plus vents and switches and figure this unit would cost about the same.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I've put a combination heater/defroster/air conditioning unit in a Sunbeam Alpine. In the process, I eliminated the fresh air intake. I've found that the fresh air intake is not really missed, the factory was kind enough to provide an alternate supply of fresh air under all conditions. The real key to effective defrosting (really defogging) is the dry air, which the A/C provides. Also, while I can divert air to the windshield, in the small cabin, it really isn't necessary. It does speed the defrosting process a little.

The benefits of A/C are so powerful that when used in a small car, the system can be way less than than optimal and still be very beneficial.

Bill

M.G. heaters are big. I tried fitting one in my book frame but it took up too much space. A compact unit looks like the way to go.

Here is a diy heat only. No water valve required since the door blocks all airflow through the core, but it would be cooler air still if a valve were added.

I just received the unit. I'll try it with inside air only.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I kind of like the heater from my 59' Sprite and the directions for operating it. There is nothing like stopping on the side of the road raising the bonnet to open the heat valve.

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John - Slow and Steady. . . Well slow anyway
Build Loghttp://www.locostusa.com/forums/viewtopic.php?f=35&t=6245

I thought having a heater in California was like having a convertible in Washington State.

Is there a way to adjust the temp or does it just not get too hot?

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

We don't all live in LA. I now live in the mountains 2 to 3 feet of snow in the winter and lived in Fort Bragg on the coast were a warm day is 65F. Anyway you can shut the doors that puts all the heat on the windshield and with the top down it's ok for awhile. Ah the good old days!

_________________
John - Slow and Steady. . . Well slow anyway
Build Loghttp://www.locostusa.com/forums/viewtopic.php?f=35&t=6245