1972 911T: Keep A/C, er wot?

[boyo]

1972 911T, stock looking with suspension upgrades. Engine will be "improved" some time in the future - just waiting for it to die, or for $6K to mysteriously appear in my bank account.

The question is the A/C: it works, but causes the engine to overheat on hot days. So, until I get better engine cooling, it's useless. Thinking I'll get rid of it, and lose some poundage.

It looks stock, except for the compressor (very square). The compressor bracket looks homemade, and is bolted onto the valve cover (!?) in such a way that it's warped it. It also gets in the way of valve adjustments!

The bit in the front trunk definitely came with the car. The radiator/condenser? under the rear trunk lid is labeled "1973" but it's a 1972 car. Doesn't look like stock, especially the way the screws have smashed down the cooling fins. The hoses also look like replacements. The piece under the left rear fender looks original.


What do I got? What's it worth? Why should I keep it? Is there some better way to keep cool when the Mercury creeps over 100F?

-Boyo

[Jim Sims]

Believe it or not your system sounds pretty much stock for a 1972. The "stock" kits were rather poorly engineered and poorly installed (some were real "butcher jobs"). The compressor brackets look like they were welded up in a farm shop. Some of the first brackets were mounted off the those little chain case cover studs and a few studs on the top of the cam towers. Later sometime in 1973 or so (?) the compressor brackets were changed to mount off the console (bracket) around the engine crankshaft pulley, the top of the passenger side cam tower with additional bracing provided by a strut mounted off the passenger side chain case top mounting stud (this requires a special nut). You need the supplemental oil cooling with an A/C system but it will be difficult if not impossible to find OEM type oil external oil cooler lines for your 1972. You can probably build up a system out of available after market parts. Many early cars have had the A/C system removed so you may be able to find a used example of the better 1973 compressor bracket. Be sure and get that special strut nut; if you have to buy it from Porsche it's $25! Your hoses are likely failing from age if original and should be replaced and it would be better to upgrade to a newer rotary or psuedo-rotary compressor and newer technology condensor (to get really good cooling often an 2nd electric fan cooled condensor is needed either mounted under the front bumper or in a wheel well) for the back lid. Since you're doing all this you may want to just convert over to R134a refrigerant. In the mean time you could have the refrigerant removed, then take off the compressor, condensor and pull the evaporator assembly out of the smugglers box (~60-70 lbs removed from car). Plug the lines and leave in place if you don't want to remove them. Value of a used A/C system zero to $500 tops; I've read of some given away for the cost of shipping. Cheers, Jim

[304065]

I say keep it: if this is a perfectly stock "T" it doesn't make sense to make yourself uncomfortable in warm (not hot) weather and go through the hassle of deleting the system, just for the weight savings. It won't make that much of a difference and the HVAC systems in the early cars need all the help they can get. If it were an "S" that you were going to be seriously tracking, I'd say go for it, but unless you have genuine performance aspirations with the car, I would stay stock.

When the temp goes over 100 there's not much that can be done, unless you go the route of an underbody condenser like Jack or one in the wheel well like Griffiths' "Mr. Ice" project. These air conditioning systems were designed in a country in which they issue a severe heat advisory when the temperature goes over 85!

[boyo]

OK then, here's the dilema: I only turn on the A/C when the outside temperature is over 90. The car overheats with the A/C on if the temp is over 95. I'd call that not real useful...

So I either need to spend $$$ improving it, or remove it. Neither is stock, but when I rebuild the engine that won't be stock either... But it will LOOK stock, that's my only requirement.

I'll look into "Mr. Ice", see what I can find out - thanks for the tip!

-Boyo

[TimT]

If your worried about oil temps with the a/c on, improve the oil cooling!!! Does your car have a front cooler? Im not sure if it was ever included with any of the "T" cars

Install an efficient oil cooler in the front fender, and your car will benefit with or with the a/c running

If your car does have a "trombone" cooler, replace it....

Like John says if you dont have any track dremas for the car keep the a/c, and make a few improvements that will beneifit the whole car, not just the a/c

[T Bird]

Boyo
Having lived with the antiquated Behr AC system in my 72 T for a while, I can understand your dilema. Consider doing what I did-- remove the system and store it away so that in the future, if you change your mind, it can always be reinstalled. In the mean time, you can experience the weight reduction and the elimination of all that useless clutter in the engine bay, the trunk, under the car, and in the wheel well.

Good luck.

[Roland Kunz]

Hello

Porsche equiped 911´s direct from the factory with the AC. However in germany that extra outpriced the most options ( You could buy a 911S or a 911T with AC for the same money )

Those kits are integratet very well.

Now for the US they delivered complete ready cars and prepared cars where dealers just added the expensive York compressor and filled the system up. ( rember back in the 70´s the $ was much stronger )

But this was still a expensive option and so most people went to aftermarked solutions. A big installer was VWoA who also installed own designed kits to Porsche.

Those kits where designed to a other aproach then the factory kits.

As the kits belong to the history of that car I would improve the faulty spots and make it work again.

Grüsse

[boyo]

Is there a good "spotters guide" for A/C systems? The bit in the front trunk clear says "Volkswagen", curious what I've got. Thanks!

-Boyo

[GIBSON]

Roland is the expert here but in my experience you can tell the VWOA kits by their large underdash units as oppossed to the small, thin Behr units. Also, Porsche usually added a condenser under the front bumper where the VW kit is usually in the right rear fender well. This is in addition to the one under the rear deck grill.
Also, the dealer-installed kits were often installed with a lack of finesse. When you remove them you'll see rather crude holes cut here and there which are difficult to patch. The factory compressor mount was a bit better than the kit but still rather
large and crude.
My opinion of these early systems was that the engineering was poor as Porsche did not spend a lot of time developing it.
If you work on a later system you'll see some real thought has gone into it's design and it works much better. I've always removed non-Behr systems because I've never had much luck keeping them working.

[Roland Kunz]

Hello

Well I´m not a expert on aftermarked and US stuff.
I have scare opportunitys to see that stuff around here in Stuttgart. Well new SUV or new 996 versions can stop right to you at the next traffic light

Also look back in time in the late 60´s when the AC system was adoptet to Porsche 911/912 they used as much existing parts aviable. Mercedes from that area also have the York and the same way the condensor and evaporator where worked out.
Now lets say if you follow the S-Class from 1968-1989 you will find 4 evolutions ( 108/109, 116, 126, 126 MKII ) and every stage had the up to date AC equipment ( The 116 had optional the first ambient controled HAVC from a european manufactorer yet they used cadillac compressor and vacuum regulation unit ).
If you look at the 911 you will find 1969-1977 with underdashvents 78-83 had integratet vents 84-86 where improved using Denso compressors and aluminium bracket 87-89 where improved with new vents in the dash and a slight biger blower. But if you look close in those 20 years Porsche changed as much as Mercedes did from the first 108/109 to the 116 with manuall controled AC. Porsche made a big improvment on the 964 but they designed the car to suit the modern AC needs. In the 60´s the AC was a add on and not very much beleived that it is a needed item in a Porsche. In the 70´s Porsche also thought that the 928 should be the car for people who need a AC and didn´t much on the 911. The 84 evolution was forced from mercedes as they stoped using Yorks and York stoped producing the compressortype. Now they addoptet the then from mercedes prefered stuff and as sold number on AC units where high they made the add on parts better too.
Also in the 70´s Porsche development division had to much to doo and to much other things around the ears to reengeneer the AC system. They main goal was that the unit worked good enough and was easy to service. Some constanty in that keept the spare parts costs low and made sure the service field didn´t had to much problems.

Now most aftermarked solutions where even worser engeneered and built in like the factory versions but they are a child of there time and when they where new the owners where happy to have them and use them.

From my sight those units are unic today and worth to show a piece of history. Its a piece of american ( PoA ) history reflecting the american marked.
Grüsse

[silver912e]

There is a nice article explaining the history of AC in Porsches here:

http://www.pelicanparts.com/techarticles/mult_AC_faq/Mult_AC_faq.htm

[RazorRacer]

Who needs a/c in a p-car when there's a/c in the lobby?

[surflvr911sc]

check out this thread-
a/c test