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Air-conditioning gas

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by RichardGibson » Mon Jun 01, 2020 9:57 am

Hi All

On Sunday (31/05/20) I took part in the Zoom Jensen chat run by the North West owners group.
It was well worth the effort and an entertaining couple of hours with participant from Oz and even Essex.
During the various conversations the subject of air-conditioning came up and triggered in my memory (my memory is not good as it used to be thanks to the onset of age) an article I had read in a Jaguar magazine I acquired as a freeby with "Classic Cars" magazine three years ago.
The magazine is called "Classic Jaguar" and as I no longer own a Jag (used to have a 3.8 Mk2 mod) I have never bought another copy.
Anyhow I remembered reading an article about a restoration company called KWE Cars based in Berkshire and included in the article was an item about th restoration of air-conditioning with particular reference to the gas used.
As everyone knows the use of Freon gas in refrigerators and air conditioning is now banned as it is a global warming gas which attacks the ozone layer.
Here is a quote from the article:-

"....many cars of the era KWE covers were designed for R12 refrigerant, which has now been banned (same for Jensens). The common assumption is that cars must be converted to use R134a, as most modern cars do now. However it isn't as simple as just putting new gas in, and has considerable expense (see price of a new replacement air-conditioning unit for a Jensen). Chris is not convinced its a good idea anyway as many of the components are not designed to work with this less-efficient refrigerant."We use RS24, which is sometimes known as Isceon MO49 or R413. It is more expensive than R134a, but the actual cost per charge is only an extra £11>17.
RS24 is non ozone depleting and no components on the car need to be changed - though we always recommend changing the receiver dryer."

As you can see it could be worth looking into if your air-conditioning is not at its best, or working at all and you do not want to ge to the expense of over a £1000.00 to put in a new unit.

For more information KWE Cars is at
86 Greenham Business Park
Thatcham
West Berkshire
RG19 6HW
Phone:-01635 30030

I hope this of help to you all, please keep well.
Richard (Scottish JOC rep)
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by SRS2000 » Mon Jun 01, 2020 10:45 am

Hi Richard good to talk with you the other day at our zoom meeting. It was great to get away from the worlds problems for an hour or so with some proper car talk. Some excellent info there to read up on. Cheers Steve R
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by slotcarone » Tue Jun 02, 2020 3:23 am

I would not use any refrigerant in any car that is not an OEM fitment. There is no reason why you cannot convert your car to 134A. Change the receiver dryer and use 134A compatible oil. Back when 134A first came out we did many R12 conversions and typically it worked fine. Others will say you must change everything and by all means do it if you have the funds to spend. The modern compressors are better than either of the ones Jensen used. :)
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by Steve Payne » Tue Jun 02, 2020 8:22 pm

I am sure Pat will be along soon but I believe you must also replace the hoses when converting from R12 to R134, if you don't the gas will escape.

Converting our cars from there original style compressor to the Sanden style is well worth the money in my view. These modern compressors take a lot less energy to drive and seem a lot more reliable.

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by slotcarone » Tue Jun 02, 2020 9:56 pm

Personally I have never replaced any hoses when doing a 12 to 134 conversion and have had no issues with leaks. :)
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by Grant » Tue Jun 02, 2020 10:06 pm

I've also put R134a in my old Jensen system with no problems.. it's been in there for 2 years now and still works fine, I done it on a wim and didn't mind if it went wrong, I did also change the valve by the bulk head which should be done too as it has a smaller aperture I think, I did talk to pat and he said I shouldn't really do it though.. I told him I would never tell anyone, but I have now let the cat out of the bag :? .. But.. I am not saying you should do it, just saying I did it and it works fine so far, I still run the old York pump as I didn't want to change that old ice cream van unit :P
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by Steve Payne » Wed Jun 03, 2020 6:51 am

The problem is the molecules of R134A are smaller than R12. They are so small they will leak through the original style hoses. If you do an ultraviolet test on a car with R134 in the system that has original hoses you will be surprised at how much you are loosing through the hoses.

In the old days when you could top up easily it was not a problem but now A/C gases are a lot tighter controlled you need to be more careful.

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by DPP » Wed Jun 03, 2020 7:16 am

I agree with Steve.

My advice is talk to Pat at Fenair he is very helpful and easy to deal with, and its not that expensive or difficult to change the pipework.
Even better to replace the compressor with a Sanden and a new condenser after 40/50 years will not do any harm.
A full system from Pat is not that expensive and compared to the cost of some other parts for our cars it seems a bargain.
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by 007aircon » Wed Jun 03, 2020 7:56 am

RichardGibson wrote:Hi All

On Sunday (31/05/20) I took part in the Zoom Jensen chat run by the North West owners group.
It was well worth the effort and an entertaining couple of hours with participant from Oz and even Essex.
During the various conversations the subject of air-conditioning came up and triggered in my memory (my memory is not good as it used to be thanks to the onset of age) an article I had read in a Jaguar magazine I acquired as a freeby with "Classic Cars" magazine three years ago.
The magazine is called "Classic Jaguar" and as I no longer own a Jag (used to have a 3.8 Mk2 mod) I have never bought another copy.
Anyhow I remembered reading an article about a restoration company called KWE Cars based in Berkshire and included in the article was an item about th restoration of air-conditioning with particular reference to the gas used.
As everyone knows the use of Freon gas in refrigerators and air conditioning is now banned as it is a global warming gas which attacks the ozone layer.
Here is a quote from the article:-

"....many cars of the era KWE covers were designed for R12 refrigerant, which has now been banned (same for Jensens). The common assumption is that cars must be converted to use R134a, as most modern cars do now. However it isn't as simple as just putting new gas in, and has considerable expense (see price of a new replacement air-conditioning unit for a Jensen). Chris is not convinced its a good idea anyway as many of the components are not designed to work with this less-efficient refrigerant."We use RS24, which is sometimes known as Isceon MO49 or R413. It is more expensive than R134a, but the actual cost per charge is only an extra £11>17.
RS24 is non ozone depleting and no components on the car need to be changed - though we always recommend changing the receiver dryer."

As you can see it could be worth looking into if your air-conditioning is not at its best, or working at all and you do not want to ge to the expense of over a £1000.00 to put in a new unit.

For more information KWE Cars is at
86 Greenham Business Park
Thatcham
West Berkshire
RG19 6HW
Phone:-01635 30030

I hope this of help to you all, please keep well.
Richard (Scottish JOC rep)


I will put my 2p's worth in here, then you can all go away and Wikipedia everything i say, :D
Ok so R12 has been banned for use since 2000, ( 20 years ago) R134a was introduced in 1992-93 and has now been phased out of mainstream use from 2013, for type approved cars from 01/01/13 and finally banned from all cars and heavy equipment for road use from 2018 ( although this seems to have escaped some manufactures or the overseeing powers have consumed too much red wine and cheese not have noticed) in favor of R1234YF which is a mildly flammable refrigerant with a proportion of natural refrigerant ( propane) to reduce the GWP ( global warming properties) .
GWP: R12: 6000
R134a : 1340
R1234YF : 4

Thats the benchmark to the substance of the refrigerant.
Biggest offenders :
Scrapping of refrigerators without decommissioning and cars.
Since 2000
Cars
Cars have a semi sealed system ( compressor has a rotation shaft and thus a shaft seal, when wear is introduced leakage occurs, older pre 134a cars way worse than new engineered ones but all leak)

Right... Grant...
I did say don't do it, but not how you are portraying, what i said is don't just shoot some gas in, reason, you are irresponsible.. Neer.. cats out of the bag..
Reason, your hoses are not barrier hoses, you should fit barrier hoses ( see sae J2064) https://www.sae.org/standards/content/j2064_199808/
The standard R12 hose is Rubber, R134a & R1234YF molecules are smaller than that of rubber, thus the gas escapes through the pipe wall.

Changing the pipes reduces the gas loss to the atmosphere, reduces your costs, and cost to the environment, of which most of us are of a age we wont see what we have left for our grand kids, the world is warming up, we are coming out of a ice age, but do we need to accelerate its warming??

The other section of don't do it grant was that the oil in your R12 system is not compatible with the refrigerant and wont mix, so you don't get good lubrication, that said you are using the York so its hardly the best of units and not worth saving.

RS24
Phased out years ago ( yes my Nan has 30 cylinders in her shed as well and my mate has 6 cylinders of R12 in his shed, there is always someone with a tail of its still out there) this was designed to get around the Rules on CFC but couldn't get around the ones on HCFC
Whats the point of using it? well it worked with the R12 hoses, nothing else.
R134 Vs R12
R134a operates down to -28C R12 to -15C ( que;" i got ice on my screen with R12 but not with R134a so R134a is crap") yes you did, but the two clearly are not the same in temperature glide, and did you change the throttle control and filter, oil etc... err NO is the answer to that.

The compressor that's fitted to the 383 started life as a air brake compressor for yank trucks, that then found its way onto truck fridge bodies, that then got adapted to cars for "air" hence why we don't fit these oversized lumps pulling 15 hp anymore, with steel bearings that dry out and spark to ignite the R49 drop in you fondly talk of, remember you have about the equivalent of 100 aerosol cans in a charge of R49, ever seen one on a bonfire that's empty... good luck..
Flares leak, evaporators can rot and leak, open the car door the interior light sparks and you will need to change your pants... R49 was a drop in for fixed hermetically sealed fridges not cars...

There is a reason i am qualified as a fridge engineer.. that's so i install the correct equipment and refrigerant to the application... Forums and YouTube google etc are great for giving the cheap fix... for every action there is a reaction... the reaction for using R49 is impressive, if you tell the tale and your insurance company does not read the fire report as to where the fire started... then it could be a £50k cheap regas.... :lol:

Gents there are reasons why we in refrigeration do what we do, and believe it or not its not to rip people off, not to sell them stuff they don't need, offering a £1000 kit when all you need to do is nip round my Nan's and use some of her RS24 :lol:

WE offer a engineered alternative to what you have that's compatible with current R134a / R1234YF refrigerants, that's also extremely fuel efficient in terms of compassion power consumption demand, as a package of new components all calibrated to function using either refrigerant, hoses that are made to retain the current refrigerants, o-ring fittings instead of flares that leak, pressure controls that stop the compressor not only in cases of over pressure but in the event of a stone going through the condenser and letting the gas escape, so saving your compressor, ( you would be surprised the amount of owners i have turn up saying its running but not too cold, only to find out there is no gas in at all as a pipe has burst through a blocked filter but still think because the button is down its on )

I will finish by saying, if a job is worth doing, its worth doing well... we all have a responsibility for the future, and not all businesses are out there to rip people off with fancy kits and parts that are not needed.

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by Steve Payne » Wed Jun 03, 2020 8:25 am

Well put Pat, I wish people would realise the days of shoving a bit of gas in or bodging up the system to get it to work for the summer have gone.

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by Grant » Wed Jun 03, 2020 9:00 am

Yes.. don't get me wrong, I would and have told everyone that has mentioned A/C to get intouch with Pat for Air-Con Image, I personally had good reasons not to fit the new type system and bought some new bits from Pat to try my system temporary. When I do my engine swap soonish I will get a new system kit from Pat, fit it and have him gas it up for meImage.. I will be really sad to get rid of my York pump thoughImage
Very good explanation by the way Pat, thank you as alwaysImageImage
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by 007aircon » Wed Jun 03, 2020 10:17 am

Grant wrote:Yes.. don't get me wrong, I would and have told everyone that has mentioned A/C to get intouch with Pat for Air-Con Image, I personally had good reasons not to fit the new type system and bought some new bits from Pat to try my system temporary. When I do my engine swap soonish I will get a new system kit from Pat, fit it and have him gas it up for meImage.. I will be really sad to get rid of my York pump thoughImage
Very good explanation by the way Pat, thank you as alwaysImageImage

No worries mate, try my best as always, not out too offend...
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by OzJensen » Wed Jul 01, 2020 10:46 pm

Interesting thread - and thanks Pat for the insights.

Personal experience with my Mk2 in Sydney - where a cold winters day is 16C and summer can go over 40C. When access to R12 was exhausted I had my system regassed with R134a in about 2005. The AC was less effective but what bugged me with both the R12 and R134a was the heavy load the compressor put on the engine especially when idling, and the AC condenser cooling fan running all the time the AC was on - the alternator only just managed the electrical load.

After my six years as an expat in Malaysia and the UK I bit the bullet in 2018 when I was back in Australia and had the system upgraded to a Sanden type rotary compressor, new Tx valve, receiver, hoses etc and now I have nice cold air again - and the best part the idle speed hardly changes when the compressor cuts in - just like a modern car. Also there is now a three way cut out switch installed so that the AC condenser cooling fan only cuts in when needed.

I like to keep my cars original but I can live with the loss of the York compressor as the rotary compressor is so much more efficient.

Hope that helps.
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by 007aircon » Thu Jul 02, 2020 5:50 am

OzJensen wrote:Interesting thread - and thanks Pat for the insights.

Personal experience with my Mk2 in Sydney - where a cold winters day is 16C and summer can go over 40C. When access to R12 was exhausted I had my system regassed with R134a in about 2005. The AC was less effective but what bugged me with both the R12 and R134a was the heavy load the compressor put on the engine especially when idling, and the AC condenser cooling fan running all the time the AC was on - the alternator only just managed the electrical load.

After my six years as an expat in Malaysia and the UK I bit the bullet in 2018 when I was back in Australia and had the system upgraded to a Sanden type rotary compressor, new Tx valve, receiver, hoses etc and now I have nice cold air again - and the best part the idle speed hardly changes when the compressor cuts in - just like a modern car. Also there is now a three way cut out switch installed so that the AC condenser cooling fan only cuts in when needed.

I like to keep my cars original but I can live with the loss of the York compressor as the rotary compressor is so much more efficient.

Hope that helps.


That's why i decided to sell the kit Tony, simply due to those very same factors you experienced both the plus and minus, R12 did not run at a high pressure, no CFC, Hydro Carbon or Ammonia based refrigerant does , but in removing the Chlorine etc other chemicals replaced the ozone depletion substance but caused the pressure built up in the compression cycle to rise dramatically.
The restriction of the jensen is the size of the condenser that can be used in such a narrow nose cone, ideally a condenser the same size as the monaro would be ideal, but there simply is not the space to get that extra 6" of heat exchanger in to the car.

I do smile as the Germans are now pushing full steam ahead with CO2 as a "natural" refrigerant, that is great , but the pressures are extremely high, last time i checked 50 Bar was being suggested, so i assume there must be a blend involved, were CO2 is in the highest content of substances maybe to still claim its co2 , that aside the power used to turn the compressor with a head pressure must be one hell of a power sapp, we have come to the cross roads again with the internal combustion engine, where the objective is to reduce the emissions , but when you change which emission it is you are trying to reduce, you increase another... for every action there is a reaction.

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by Basil McKinley » Sun Jul 05, 2020 1:45 am

I do smile as the Germans are now pushing full steam ahead with CO2 as a "natural" refrigerant, that is great , but the pressures are extremely high, last time i checked 50 Bar was being suggested, so i assume there must be a blend involved, were CO2 is in the highest content of substances maybe to still claim its co2 , that aside the power used to turn the compressor with a head pressure must be one hell of a power sapp, we have come to the cross roads again with the internal combustion engine, where the objective is to reduce the emissions , but when you change which emission it is you are trying to reduce, you increase another... for every action there is a reaction.


There is no 'ideal' refrigerant. CO2 was a commonly used refrigerant up until around the 1930's when it was displaced by CFC's which have now long been phased out due to their ozone depleting properties. CFC's (including R12) were replaced by HCFC's (including R134a) which are now in turn being phased down as they are potent greenhouse gases. R134a has a global warming potential (GWP) 1,430 times that of CO2. The latest synthetic refrigerants are the HFO's (including R1234yf with GWP of 4) which are extremely expensive and mildly flammable with toxic products of combustion. Over the last 15 or so years CO2 has made a gradual comeback aided by technical innovations. Now days virtually all new supermarket refrigeration systems use CO2 refrigerant. CO2 won't condense at temperatures above 31°C so modern CO2 refrigeration systems operate on a different (transcritical) cycle to that used with other refrigerants.

The ac system on electric vehicles will be reverse cycle in order to provide cabin heating far more efficiently than electric resistance heating thus extending vehicle range,

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