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MG MGB Technical - Vintage A/C systems

I have finaly accumulated enough parts to try to start to add A/C to my 73B. I am adding mostly vintage parts and I am trying to make it look as correct as possible. Could anyone with a correct A/C system, or knowlegde of one, tell me where all the bits are mounted. I was specifically wondering about the dryer, how the condensor fits(ie distance from radiator, ect..), the blower(I have two and they look the same, does it go motor towards bulkhead and then which way round? I appreciate any help anyone can offer me and I am going to have a go this weekend anyway, but it would be nice to have some idea's and pointers.

Thanks in advance,
John
J Arthurs

John,

With a 1973 the brackets for the compressor will be a challenge if you plan to retain the air pump? I do not have AC on my 1974, but have seen the (factory/dealer) arrangement which located the compressor over the air pump and alternator. You might wish to attend local shows to find someone with this in place.

Also, check out <www.vintageair.com> who make systems for the hot rod trade. They have installation details that might also be of some help.

Regards,

L.C.

Larry C.

Here's how it's installed on my 71 GT. The A/C system was on the car from new. I won't use the word "original" as someone will then point out that no car left the factory with A/C installed.

There is a bracket mounted on the side of the block for the compressor, air pump and alternator. The compressor is underneath, approximately where the alternator went. The alternator is mounted outboard of the air pump, which stayed in it's stock location. The alternator is on a fixed mounting, and belt tension is adjusted by moving the air pump.

There is another bracket, round tubing flattened on the ends, which runs from one of the head bolts to the compressor bracket. The inlet air filter for the air pump is mounted to this. The condenser is located about 4-5 inches in front of the radiator on a vertical orientation. The stock fan has been replaced with a larger six-blade metal fan to make up for the radiator blockage caused by the condenser.

The receiver/drier is mounted on the right side inner fenderwell, and the hoses connecting the compressor to condenser and condenser to receiver/drier run through the radiator support panel via the holes where the oil cooler lines normally go. The oil cooler lines are rerouted under the radiator support panel. If I was doing this, I would reverse the placement of A/C and oil cooler hoses, as this would allow for removal of the engine and radiator support panel w/o disturbing the A/C system (PITA to have to evacuate system to remove engine).

The evaporator is mounted under the passenger side dash, with hoses connecting to four triangular pods with rounded air registers. The controls are simply 2 rotary switches mounted on the outermost drivers side pod.

I have some pics of the system installed, both engine compartment and interior. Email me offline w/your address and I'll send you a set. I had double prints made. If more than one person wants them, I'll take the negs down and have them put on a disc for Emailing.
Paul K

Just to clearify, the car does not have an air pump and the related emissions equipment as it runs better without. I basically have 2 complete systems. Both compressors are the later senyo??? type. By the looks of the brackets they must mount where the alternator is now with the alternator on top. I have 2 blowers, a king air and a frigidaire. They are nearly identical in size and design. I have 3 dryers, one has 2 pressure??? switches, one has one, and one has zero. The two condensors are different sizes. I decided to go with the frigidaire blower and the larger condensor.
The replies so far are extremely helpfull. I am not really concerned with 100% originality, but did not want to have to hack the car up to make it fit. The new systems I have seen for sale are not designed specifically for MGB's and I had my doubts as to how well they would fit.
I am planning on fitting the hardware and wiring it up, and then taking the old hoses and fittings to an A/C specialist and have them make new lines to fit and charge it up with R-12.
I am planning only only wiring up the highest fan speed and plan on using a relay. Does anyone know how the compressor lead should be wired? I was hoping to use one of the pressure switches inline and just wire a switch. Would this work?
J Arthurs

I have the original installation instructions for a system for 68-71. I can scan them and send a file. Send me your E-mail address
Chris B

John, If you have the MG Sanyo mounts the compressor does go in place of the alternator. The alternator can be mounted on the mount for the smog pump. The compressor mount I had mounted to the timing cover and front plate. There should be an idler for belt adjustment. On the 73 you may have a problem with the fan hitting the compressor clutch. It it does the fan will need a spacer under it and the radiator will need to be shimmed forward. There should be an alternator adjuster bracket that is fastened to the front of the compressor. The rear of the compressor is attached to a modified alternator bracked. I had a complete system on my GT and removed and sold the parts. I deleted some photos about two weeks ago that would help but I can't call them back.

I wouldn't use an old dryer as the silica is probably contaminated, you AC man will probably suggest a new one. My dryer was mounted on the fender well as Paul mentioned. Cooling will be a problem, stock fan will need a good shroud, Paul dosen't mention it but I assume there is a cooling fan on the coadenser. Some people are installing the condenser flat under the radiator support duct with an electric fan for condenser cooling.

If your blowers are like the one I had, big squirrel type, it goes on the shelf in front of the firewall where the emissions cannister normally is located. The orientation of the blower is dependentent on the matching the blower hole in the evaporator and you will have to cut a hole in the shelf to match.

The system I had was an MG dealer installed item and it had three air outlets, one on each side of the dash, the headlight switch and brake test lit were removed and installed in the A/C control panel which was under the left side of the dash.

The compressor wire needs 12 volts and should be controlled by the A/C thermostat through a relay.

It appears there were several variations of A/C systems used over the years in MG so nothing is consistant. When I removed mine it looked like the dealer? used an air chisel to cut holes in the dash and on the firewall shelf.

I took mine off because it was in poor condition, make normal maintenance more complex and I'm retired and stay home or take a modern car when I need A/C. Hope this information helps give you some ideas. Good luck, Clifton


Clifton Gordon

The discription Paul outlines are identical to the layout on my 73. I am removing mine if any parts are needed.

Ken Knize
Binghamton NY
Ken Knize

This thread was discussed between 27/08/2002 and 30/08/2002

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