MG Sports Cars

I see a lot of folks using Vintage Air GEN II mini evaporators. Is this a particularly good product? Does anyone have experience with other brands? I want to delete the BMC heater/defroster and replace with a cool/heat/defrost unit.

Hi Geoff,
This my 4th season now with that particular unit and I am happy with it. The mini evaporator does alot of things for you. While moving, it will put out "ice cold air", but stuck in traffic, you'll get cool air. Still much appreciated. I've got good air flow through the condensor. Maybe a larger condensor than the one they supply would improve things but I'm not going to mess with it at this point.
Good luck

Geoff,
Check out nostalgicairparts.com in Tampa Fl.They make a unit for MGB.Has a heater coil.You can get the ac brackets
from D&D.
Mike

The Gen-II mini is a great unit with ton's of popularity in the hot rod community. It won't fit behind the dash of an MGB without modifications but there are good pics on this site to guide you. There's also the vintage air short pack that can be installed up under the passenger side like Leonard Marshall's car.

[www.oldairproducts.com]

I think the hurricane is smaller than the short pack

Rob, I've been using the pics in your build journal as a reference. Very helpful since my car and I are on opposite sides of the planet. I've talked to Vintage about separating the blower and mounting it remotely. Possible. I've looked at the Hurricane unit. Width and depth look ok but it may be just a tad too tall to just slide in. I'll work on that. Next idea is to find an import evapoator that tickles me size wise and work out the other components piecemeal. Thx for you input.

It's very easy to seperate the blower from the Vintage Air Gen-II min. It is a seperate housing that's screwed onto the main housing with about 3-4 screws. I'm sure you'd lose a little efficiency but probably not noticeable in a car as small as an MG. I did get feedback that the heater on the short pack is marginal -- probably ok in a climate like FL has. Gen-II mini has good A/C & heat.

Note, I modified the square cross brace to make room for the Gen-II mini. Doing that, I have not remoted the blower & you don't need an access hole on the firwall side. Ted Lathrop, on the other hand seperates the blower motor & mounts the evap box partially in the box section of the firwall behind where the OEM heater was. Doing it that way you don't have to modify the cross brace but it's a tight squeeze. Net is two ways to do it.

I've looked at all your pics Rob. Looks like a good way to do it. Ted Lathrops method is clean when finished but as you say, tight. My goal is to keep the unit in the cockpit but hidden completely. Did you have to trim the bottom of the dash when you pulled that lower Xbrace out? Since I'm seperated from my car I can't take a tape to it. Is there room to notch into the old heater well forward of the center console?

That square tube that runs side to side behind the dash is there to eliminate a vibration or shake at speed. Larry Shimp told me he'd read that in one of the MG books. So, what I did was cut it out a few inches to the right of the steering column mounting points & wide enough for the AC evap box to fit. Then, I welded in 1" spacers & some new square tube to reconnect it -- result is moving the square brace inboard by 1". That gives me just enough room to slide the AC evap box up behind the dash behind the square tube. Because the tube is now 1" further inboard & the center console brace attaches to it, I also had to cut that loose & move it inboard to line up. I flipped it around 180* so the flat side was at the back. That provided the room necessary behind it to be able to slide the AC evap box down & then out to the side if it ever needs to be worked on.

I mounted it pretty high; only about an inch or inch and a half shows at the bottom. I haven't yet but will make a cowl to hide it a bit more but even the way it is, it's hardly noticeable.

Down sides of the approach I took (in addition to it being a lot of work) are :

1. You'll want to pay attention to what you have in the dash in that area. I had planned to have my Vintage Air switches there, but the temp setting switch with the capilary tube wouldn't clear the square tube - it was too close. I was able to put some switches & my water temp & volt meter gauges there instead though. I have a metal dash on my car & they are a bit straighter than the padded dashes which curve forward in the middle. With a padded dash you'll have even less room between the back of the dash so check clearances carefully before committing to this route.

2. You may need to fabricate a fiberglass or other plenum to connect from the evap box defrost outlets to the defrost vents. I've played with the hoses & desn't look like I'll be able to use them. This will be easy -- just use cardboard to make the form & then fiberglass it.

3. Lastly, since this method includes flipping the metal center console brace 180*, the later style console/arm rest likely won't fit any more & would require modification. I'm not using that in my car so that didn't bother me. The early style center console that was used with the metal dash cars should still be usable with little to no modification.

Rob.
Thanks for the details. I am considering using a smaller unit. Apprx. 16"W X 12"D X 6"H. I need to slide it in on the engine bay side using a firewall cutout and fabricate a shroud to cover it. Upside, I think, is ease of install and smaller firewall cutout. Downside is getting defrost sorted. I plan on turning the cool air vent on top of the cowl into a heat exhaust vent for the engine bay. To compensate for cutting the firewall, I'll put a sheet metal doubler on the cutout area and drill 3/8s holes thru the firewall and the doubler to create a new vent into the existing air cool vent. Should be a nice low pressure area right there to help evacuate some of the heat.

That will be a high pressure area at speed but should work idling in traffic. Has anyone considered building their own evaporator box? I haven't really looked at it that closely but that seems like the most promising option to me.

JB

Jim,

You're correct. The area directly over the vent will build up a higher pressure than the faster air moving over the car. The faster flow will, I hope create enough of a lower pressure area just above the windshield to help evacuate some of the HP air.

Geoff.

I rigged one up with some parts out of the boneyard, dont quite have the ductwork started yet but its a start.I used an evap from a Kia Sephia ( I know! dont laugh !) only because the wifes old car needed a dash so I got the evap& parts along with it!
I cant get the pictures in here from work but i'll see if I can later, There are a couple pics in my project journal of it if you want to look in there.

On the high pressure subject @ the cowl fresh air grille, Has anybody checked the difference with or without a cowl hood scoop?

John,

Do you have the dimensions of the Sephia evaporator? I'll look in your journal. As to a hood scoop, I suspect the ram air would have to help but you'll be limited by the size of the exhaust duct (where ever it's located).

Geoff

I was thinking that with a big enough blower (which I already have on the car) it might be possible to leave the stock heating system mostly intact and add the evaporator behind the dash. That might require the use of the early flap doors for the footwell vents (I have a set of those, but not installed) and there may not be enough room to retain the fresh air door or that might need to become the recirc air path by blocking off the cowl vent. (with a big hole in the hood I don't get any cool air from it anyway)

There are a few interesting evaporators in the 4 seasons catalog. For instance, VW used one that is 26" long by 5-1/2 by 3-3/4 inches. That should fit into the space back there easily enough. Then there are also many options about 10 x 10 that should go behind the center console.

JB

The box is 10 x 11 x 12 that came out of the car, I had to modify it to go under the rh brake pedal box due to the dash didnt give me enough room. The core is 9 1/2 wide x 6 high x 12 from what you can see in the footwell to the manifold for the lines.
I used a different type of blower than what came with the Kia box as it was too big for what I could fit into my rig.