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MG MGB Technical - AC vent tubing

Hello. Restoring a '72 BGT and installing a Moss AC unit. Yeah I know, not original, but it gets a tad warmish here in the summer. I want to route the center two AC hoses via the stock fresh air vents instead of using the Moss-recommended method of mounting the hoses and "eyeball" outlets to the console. Somehow I need to splice into the stock fresh-air vent hoses to do this. Looks a bit tricky as the original fresh-air hoses are not uniformly the same diameter and are molded into one piece. I need to fabricate a T-fitting and some kind of adapter for the hoses. Just wondering if anyone has dome something similar with the Moss AC unit.

Thanks,
Tom
Tom Custer

"has dome something similar with the Moss AC unit.

Sorry, meant to say has anyone done something similar.

Tom
Tom Custer

Tom: I am facing a similar problem with my '74 BGT that's getting a V8. You can't use a T-Fitting because the face level vents are plumbed directly to openings in the cowl of your car. If you want to 'T' into the hoses, you'll have to build a valve system to be able to block the openings to the cowl so that you aren't trying to air condition the outside. If you don't mind eliminating the fresh air feature, you'll have to remove the face level vents and their connecting hoses to the cowl and block off the cowl openings, then cut up the molded hoses to make right angle bends to fittings the correct size for your evaporator. When I get done with my ZA Magnette, I'm going to measure up the cowl openings to see if I can make up a valve system to close off the fresh air when the A/C is on and open up when the A/C is off to preserve the fresh air function.
John Perkins

John thanks for the info. I feel rather foolish because I realized after posting my question that T-ing into the fresh air vents was not going to work!! As you've pointed out, there needs to be a way to block the incoming fresh air.

Thanks again,
Tom
Tom Custer

Tom
I was considereing the Moss AC Unit for my '70 Gt. What are your thoughts on the installation so far? Does everything seem to fit ok. I was reading their install instruction sheet and they suggest an additional $100 Plus in upgrades, did you think the xtras are needed? For the price they should have included EVERYTHING!
Mike
MK Mike

Mike, it's too early to give an assessment on the Moss AC unit because all I've done so far is install the evaporator bracket in the cockpit. The cockpit is bare so now is a good time to try to figure out how to route the vent tubes. Would be difficult to do in a finished car unless you route the tubes as per the Moss instructions.

The AC package seems to be well engineered. The compressor is a Sanden unit and all the other bits and parts seem to be well constructed. Moss does recommend that your cooling system be in top condition (or upgrade the radiator). They also recommend an overflow bottle, fan shroud, and a cast iron water pump (aluminum may crack from added stress of the compressor). I'm ok with all of that except for the water pump issue. I didn't know that Moss had cast iron pumps -- thought all replacements were aluminum. The instructions say that the cast iron pump is part #434-035.

Tom
Tom Custer

The cast iron water pump is available for all years. When I recieved my supercharger kit, a cast iron water pump was included as part of the complete package. So it should have been with their AC kit. The load on the aluminum pump will cause it to break. I went through two of them! RAY
RAY

The fresh air vents, thats the ones in the dash, do nothing that I can see. At full speed they produce a small breeze, but then again so does every thing else, which is particularly noricable in cold weather. The foot well vent is more effective.
That's not counting the top being down, which makes the vents superflous anyway. I believe that they were installed because all cars in the '70's had them. On hot days I open up the quater windows all the way so they are pointing forward which gives a nice breeze.
I suggest that that you entirely take over the fresh air vents for the air con.
Peter Sherman

Maybe 45 degrees in Melbourne makes the fresh-air vents pretty ineffective :o), but I find them useful in the UK. I remember driving a 'modern' car in central France in temps of 30 plus and we didn't know what to do for the best - closing the windows and having all the internal vents open and the fan on full was like being inside a oven, having the windows open was like being inside a fan-assisted oven.
Paul Hunt

I agree with Peter Sherman. Use the existing vents for the aircon. On a hot day, the aircon will be on & the vents will be used to their best advantage. For normal fresh air ,the quarterlights can be used. Another thought is that the plenum chamber could then be vented into the engine compartment assist heat escapement or induction intake.FWIW,Barrie E
Barrie Egerton

This thread was discussed between 13/02/2009 and 23/02/2009

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