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Merv

AC control switch

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Have just finished fitting new bushings to the G50 shifter and noticed at the end of the process that the AC Control Switch TUBE is broken, and probably had been for a while.  I could repair it with a soldered sleeve but the inert gas inside would have evaporated.  The AC seems to work OK,  but how critical is this temperature sensor to the system and:

Is there anywhere can I get one in Australia?

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Merv,

If you mean the AC thermostat, they are not that expensive but I understand that some require you to do a minor modification to make them fit nowadays.

https://www.pelicanparts.com/techarticles/911_ac_tswitch/911_ac_tswitch.htm

https://griffiths.com/product/ac-thermostat-switch/

I'm sure James at Autohaus will have one

Because the capillary tube is broken, does that mean the AC compressor is operating all the time since the there is no pressure in the tube to operate the cut out switch?

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Looking at the unit Peter, someone in the past has put fuse connection across the wires to the thermostat switch, bypassing it.  OK as a temporary fix but there could be freezing elsewhere in the system.  If so lucky! I will try James at AH. Thanks 

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Most likely place for freezing is in the evap.  If it runs happily for hours on end you're probably in the situation where it's not getting cold enough to freeze - not unknown in porsche AC circles.

However you don't have any temp control, just whatever the system will run at is what you're getting.

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I will go through the whole system in a month or so and probably replace the hoses and components with Griffith stuff.

 

After reading this from one of our members, one could get disheartened:

 

 

 

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Hi Merv , the problem with internet forums in regards to posting a picture or a screen shot from a movie without a following explanation in regards to its context can get completely lost in translation ( I have no idea at all what you are tying to imply ? ), you will often find its better to stay with the technical subject at hand and leave it at that .

The information I provided ( for free ) is so you or anyone else can gather basic background technical info about what they are actually dealing with , that way ( knowing more about the basics of a given subject ) can save you a lot of time and MONEY in not having to work out( understand ) the basic flaws the HARD way , meaning you are not having to spend twice as much time and money when you do not need to ( going around in circles )  , this could be about lots of subjects , but the basics remain , it helps enormously to know what you are dealing with .

Another basic bit of info that you need to know }

A ) the 911 series up to and in including the 1989 year model  3.2L NA & 3.3 Turbo is that the car itself going right back to the early 901 ( 1964 ) , was never ever intended to have A/C , which was extremely common with nearly all car makers in the 1960's & even the 1970's as car makers struggled to get any 1960's / 1970's automotive A/C equipment / parts that would even vaguely fit and nearly all the 1960"s automotive A/C compressors were very large and extremely heavy & would vibrate hence why the use of lots of steel ( more weight ) was ended to just keep the heavy A/C compressor on the engine , it was all a terrible compromise , but that was the 1960's and 1970's & 99'% of cars available to have A/C as an expensive option were all " Non Integrated ", meaning they were true "Add Ons " and thats how Porsche did optional A/C on the 911 up to 1989 & the 924 , 931 & the 944 series up to 1985 , all these cars had remote A/C evaporator assemblies & all of them interfered terribly with the passenger leg room

Note }  Non integrated or sometimes called "Under Dash " accessory A/C was extremely common on Australian cars here in Aus all throughout the 1970's and because the the Holden HQ or Ford Falcon XW / XY / XA etc ( with common bench seats ) had heaps of room for the famous Mark IV A/C system and it worked really well because there was a heap of room for everything and a massive radiator with a massive grille ( air intake ) at the front of the car where you would fit a MASSIVE condenser in the air flow , it was all basic kindergarten  Physics 

Note 2 } Integrated A/C means that the A/C evaporator and all its plumbing & fan + TX valve and de icing switch is mounted into a purposely designed and made heater / climate control box that in mounted in the dash ( this has to be designed in the early car design ) & this gives a very short path for the cooled A/C air to travel to the vents & will naturally give the passenger a lot of leg room ( all very neat and tidy )because the evaporator box is NOT in the passenger foot well 

Note 3 } The 911 series > 1989 had no front grille / air intake to a place where you could install a large A/C condenser , there was no room and hence no air intake , hence the compromise of a tiny horizontal front condenser & another one on the engine lid ( other end of the car )

Note 4 } The first road car I can think of that Porsche designed from the ground up with A/C to be built into the car ( integrated ) was the Porsche 928 series , designed in the very early 1970's & first production in late 1977 ( 78 year model ) A/C was standard and hence integrated 

B )  We can thank the Japanese manufacturer's like ND etc for perfecting smaller and smaller alloy multi piston and very efficient / smooth running  A/C compressors which over time got even better and in some cases cheaper due to mass production & the Japanese car companies were the first to have inexpensive & reliable integrated A/C as a factory option , these mid 1970's Japanese cases often rusted away long before the excellent A/C event thought of giving up working , it was a mild shock & a bonus ( in the long term ) to the European car makers how the Japanese were becoming the go to experts in Climate control / A/C for cars , basically the Japanese A/C designers and manufacturers took us all out of the cave man era of automotive A/C 

Regards
Bruce B

 

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Sorry Bruce I meant no disrespect in any way.  I copied the original forum link and pasted it and that image came up.  Not sure why.  I found your information extremely informative and helpful, but disheartening somewhat as the system in the later 911's seems flawed in design (esp., condenser location and operation) and is likely to be average at best.  Am I correct in this?  I am reluctant to go down the route of getting the existing system refurbished and tempted to consider a redesign of the entire system with more modern components.  Is this possible?

Merv

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The redesigns you suggest is already addressed in the market - either with the electric Ac kit or the more conventional route of upgrading the components with modern equivalents in the same layout.  That means more efficient compressors, condensers and evaporators.  If you have a post 86 car you st least have the larger dash vents to move the cold air through.

RHD cars are at a disadvantage because they can’t  use the smugglers box and do lose legroom.  The electric Ac kit fixes this by having the evaporator inside an ac box as Bruce mentioned modern designs have.  Other designs keep the passenger foot Evap for RHD cars.

Good AC in a 911 means more condenser area, more efficient compressor and more air volume through vents.  All the things not available in the 60/70/80’s.  The late 80s cars (which is what you have I think?) do have better compressors and better vents though.

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Thanks Bruce and Coastr.  That makes sense.  The electric option is an attractive one and it does come down to how much you want to spend, as you say..  Are there suppliers/installers in Australia and does the system work well in RHD cars?

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11 hours ago, Merv said:

Thanks Bruce and Coastr.  That makes sense.  The electric option is an attractive one and it does come down to how much you want to spend, as you say..  Are there suppliers/installers in Australia and does the system work well in RHD cars?

PFA'er Porkchops has imported at least 2 Classic Retrofit electric systems and would be worth contacting.  Good thread here:

http://forums.pelicanparts.com/porsche-911-technical-forum/921754-classic-retrofit-lightweight-electric-air-conditioning.html

Comes down what level of cooling you want and how much you want to spend.

If your current system is in good condition and you don't drive in traffic or generally less than 60kph, you might be happy after some repairs, a trinary switch and a regas.  If you want better low speed performance you might find just adding a rear wheel well condenser with fan will do the trick.    

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I think you are right Peter.  The full electric system seems over-kill for the car use when considered against the price involved.  I will start on the existing system in a week or so and see what the weak points are.  PeterG here has the same model and is seeking the same result, so we can compare notes. 

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My two bobs worth

Update the condensor(s) if required, renew the hoses as required, add a 10" thin line scimitar (curved) blade thermo fan (or two but probably not necessary) on the rear engine lid condensor.  They are aerodynamically more efficient, and look cool, but I couldn't find a scimitar fan when I was doing mine.  The 930 has a square condensor in half the wing because there's a funny radiator thing that takes up half the vent space, but you get the idea.

 

IMG_1346

The scimitar fan

fullsizeoutput_5

I wired it into the compressor circuit, to cut in and out with the compressor or you can wire in as a manual switch to turn the fan(s) on and off as required (as PeterM said, above 60kph turn it off), wire in a compressor bypass to take advantage of the centre vent fan when AC is not required, update the evaporator, if required or consider the retro-fit half kit to move the evaporator from under the floor with a more efficient fan and gain passenger leg room.  

If you keep the evaporator under the floor consider modifying the drain at the bottom.  The factory grommet design (pictured below on rhs) encourages water build up and possible overflow onto the carpet.  I sikaflexed the grommet in place then sliced the inside part of the drain grommet off so it was flush with the inside surface of the casing.  Also some evaporator cases don't have a front dam and can overflow should the water build up above the drain grommet, particularly when accelerating.   Mine didn't so I added a dam made from perspex.  Also the case join is a potential source of leakage.  Rusted clips is a giveaway.

IMG_1052

Here's another dumb thing that Porsche did.

600_0615110102018_imageeditor_P_Resitor_b4

This is the fan speed coils mounted directly in the vent, restricting the air flow.  The pictured set up is in LHD cars, in RHD it is in the curved vent pipe after the evaporator (Pics 3 posts below).  I think they did this to keep the resistance coils cool, but who knows.  It doesn't appear to be as restrictive in RHD cars but it's there, well it was.  I now have a motor with internal speed control. (above).  At the top left is the tube that the old fan speed coils were mounted in.

EDIT: and in the plastic container at the top of the pic is the old coil pack.

I think I spent more than two bob, hope this helps.

 

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Found some pics of the fan speed resister coils in RHD car (mine)

DSC07344

and gone

DSC07348

 

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Unfortunately the rear condenser on a 3.2 attaches under the engine lid leaving precious little clearance for a electric fan.  I've seen some fit a couple 6 inch fans and a 7 but that does look like a dog's breakfast and I'm not sure how effective in the end.

Appears if you want good low speed AC performance on a 3.2 the best thing to do is fit a rear wheel well condenser and fan.  I bought a Zims but was unhappy with the fit and mount and now plan to buy a 964/993 condenser, which are relatively inexpensive, and fit that instead.  However since moving to a town with only 2 sets of traffic lights the need has dropped way off!

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59 minutes ago, Peter M said:

Unfortunately the rear condenser on a 3.2 attaches under the engine lid leaving precious little clearance for a electric fan.  I've seen some fit a couple 6 inch fans and a 7 but that does look like a dog's breakfast and I'm not sure how effective in the end.

  However since moving to a town with only 2 sets of traffic lights the need has dropped way off!

and day temperatures of 15 degrees, if you're lucky, and a 10 minute drive home,  you may as well pull the system out. 😎

I was wondering about available room on a wingless 911.  Are you talking about computer fans or something else ?

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But we are so much closer to the sun here than you low landers!😊

Not quite computer fans but some of the smallest electric automotive I've seen.

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1 hour ago, Peter M said:

But we are so much closer to the sun here than you low landers!😊

Not quite computer fans but some of the smallest electric automotive I've seen.

How about this then? More the hillbilly style, 

https://www.ebay.com.au/itm/8-12V-Portable-Dashboard-Vehicle-Auto-Car-Truck-Fan-Clip-On-Oscillating-Cooling/193080303658?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D01a49f489a5a4fd196279032627a8256%26pid%3D100005%26rk%3D5%26rkt%3D12%26mehot%3Dlo%26sd%3D222808782410%26itm%3D193080303658%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851

just clip it above the vent and blow the air in 🤣

 

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On 12/09/2019 at 18:13, OZ930 said:

and day temperatures of 15 degrees, if you're lucky, and a 10 minute drive home,  you may as well pull the system out. 😎

I was wondering about available room on a wingless 911.  Are you talking about computer fans or something else ?

Most 911 wings don’t actually have more room.  The condenser is still mounted by factory in the same location whether a wing or not.  You could always rig something up on top of the decklid and under the tail, but the factory didn’t do it that way.  See the 930 pic above for reference - even though the intercooler sticks up the condenser is still mounted under.

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