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Discussion Starter #1 (Edited)
I have a problem with my AC on my Alfa Montreal does not cool as good as before after I converted it from R12 to R134 and even changed the compressor to a new, more modern from Sanden

Began to suspect faulty expansion valve because the old one was made for R12 and R134 i switched it but it was not better.

With the old compressor with R134 the cooling was really good though it sounded like a rock crusher.

Can it be that the new compressor is more effective so that the condenser does not have time to cool down the gas as well as a modern condenser based on parallel thinner tubes instead of vertical large diameter pipe as the old one

Most people i have asked want me switch to a more modern condenser

How have you done the conversion people out there that has a newer compressor?

Did you get any problem with the cooling performance ?

I also suspect the heater valve leaking a little so the heater core varm up the air but i cant feal that the return hose getting warm so it is a long shot :)

I am going to test this tonight if i put a clamp on the return hose so no water can get through the heater core.
 

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Hi again. Further to my previous reply, I did a 134A conversion to a Mercedes I have. Fitted a parallel flow condenser and a Sanden compressor. The result was quite satisfactory. The AC on the Merc. ('71 280SL) is even more of an afterthought than the Montreal (Mickey Mouse ?) I have not been able to find a suitable parallel flow condenser for my Montreal yet, and want to install a Sanden, so would be interested in the model you used. Of course, you may have more than a condenser problem, so good luck. Cheers, Dale.
 

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For R134a a PF condensor is a must-have, and there are plenty of generic choices available on eBay. Just pick the largest which will fit. You need new hoses, but you needed them anyway. Any decent a/c shop can make them for you. Stick with R12, if you can, as it is available, or consider R152, which is very inexpensive, readily available, and it chills like nobody's business. Google it. I don't have a Monty, but my Euro BMW 635 has the worst factory a/c ever, and the PF, R152, and a Sanden compressor have resulted in a fairly good system. Will do the same on my '92 Spider when I get around to it.
 

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Unfortunately, all the generic PF condensers that I've found are too large for a Montreal. Under hood space is limited, and mounting in front of the radiator doesn't appear to be an option.
 

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This thread shows cars with factory A/C installed and removed.

(Sadly, my friend sold the car before we sourced all A/C components -- the intention was to get the car ready for driving to next's year's AROC convention, but plans changed).
 

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Wow, never seen anything like that before, nor have I seen a PF condensor that will fit that tiny area. I'm in Florida, so I have to ask, how hot does it get in Sweden? R134a seems like it would be a complete waste of your efforts. R12 or R152 would be the only refrigerants I'd even try.
 

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Discussion Starter #9 (Edited)
Hi again. Further to my previous reply, I did a 134A conversion to a Mercedes I have. Fitted a parallel flow condenser and a Sanden compressor. The result was quite satisfactory. The AC on the Merc. ('71 280SL) is even more of an afterthought than the Montreal (Mickey Mouse ?) I have not been able to find a suitable parallel flow condenser for my Montreal yet, and want to install a Sanden, so would be interested in the model you used. Of course, you may have more than a condenser problem, so good luck. Cheers, Dale.

Here is a link to my project with pictures
https://www.alfapower.nu/viewthread.php?tid=27575&page=26

The Sanden compressor is a SD7B10 and are used in many HotRod Builds in the states it is the smallest compressor you can get.

I order it from Aliexpress in China if you want it cheaper all sanden compressors are made in china.
http://www.aliexpress.com/w/wholesale-sd7b10.html?spm=2114.01010208.0.49.rtx2CS&initiative_id=SB_20160628003058&site=glo&SortType=price_asc&shipCountry=de&g=y&SearchText=sd7b10

The rest are factory AC parts for the Montreal including the condenser.
 

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Discussion Starter #10
Wow, never seen anything like that before, nor have I seen a PF condensor that will fit that tiny area. I'm in Florida, so I have to ask, how hot does it get in Sweden? R134a seems like it would be a complete waste of your efforts. R12 or R152 would be the only refrigerants I'd even try.
It can be quite hot some times in the summer but the main problem is that the R12 was gone in the 1990 and we doesnt have the DIY kit you have in the US with R12 gas.

They came to Europe about 2010 now many companys are importing them from the US :) with a HC gas that are a better replacement then the R134 more like R12 but not so effective.

About the PF condenser i think i have to see if i have to custom made it but that will be a project this winter.
 

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Hi Reine. Thanks for the Sanden information and photos. I'll look in to that. It sure is compact, do you feel the performance is fine ? I feel, at present, the only advantage, although a nice one, without a PF condenser, would be replacing that heavy, noisy, original unit. I am somewhat determined to try and overcome that "Hiccup". If I succeed, I'll let you know.
 

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Discussion Starter #12 (Edited)
Hi Reine. Thanks for the Sanden information and photos. I'll look in to that. It sure is compact, do you feel the performance is fine ? I feel, at present, the only advantage, although a nice one, without a PF condenser, would be replacing that heavy, noisy, original unit. I am somewhat determined to try and overcome that "Hiccup". If I succeed, I'll let you know.
The performance are not so good for the moment i think i have problem with my heat valve or the compressor is to effective to pump the gas around the system so the condenser can´t cool it down.

But i think i can improve it if i get a custom made PF condenser.
You dont even notise when you start the compressor no hickup from the engine etc

I missed to mention that the compressor have different pulleys to choose from so they fit Montreal standard belt but i custom made a new pulley for the more common Poly-V belt and they have less noice.
 

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Discussion Starter #13
Isn't the original condensor in front of the radiator? What size is it?

Here is a picture of the Montreal condenser.

I dont know if it is possible to custom made this to a PF condenser.
 

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Hi Reine

R134a is a less efficient refrigerant than R12. If you simply change the refrigerant in the system, without doing anything else the system's cooling performance performance will drop 30% or more and effectively render the system useless. This information is available in countless AC forums and pages on the internet.

When converting to R134a upgrading the condenser to PF version is the minimum change required.

You might consider going to one of the various propane or hydrocarbon based refrigerants. They are as efficient as the R12 refrigerant.

The other issue is refrigerant charge. R134a typically requires less refrigiant by mass than R12. So if the system used to have say 2.5lbs of R12 it will require less R134a. Having too much or to little refrigiant will produce bad results.

Bye for now
 

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Discussion Starter #15
Hi Reine

R134a is a less efficient refrigerant than R12. If you simply change the refrigerant in the system, without doing anything else the system's cooling performance performance will drop 30% or more and effectively render the system useless. This information is available in countless AC forums and pages on the internet.

When converting to R134a upgrading the condenser to PF version is the minimum change required.

You might consider going to one of the various propane or hydrocarbon based refrigerants. They are as efficient as the R12 refrigerant.

The other issue is refrigerant charge. R134a typically requires less refrigiant by mass than R12. So if the system used to have say 2.5lbs of R12 it will require less R134a. Having too much or to little refrigiant will produce bad results.

Bye for now
Hi

I am using the Hydrocarbon replacement gas so thats why i am a little confusing.

I have tested more or less refrigerant with no luck.

But what the problem today is that you are used to get more cooling that you have in modern cars and they are using PF condenser.

But i think i have a solution to put in a PF condenser in front of the radiator the problem is that i have to drill 2 holes for the ac hose and modify a steel deflector in front of the radiator not a big job just have to do so that looks as it have come as factory install finish :)
 

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You need to base the amount of refrigerant on the original amount of R12 in the system. For example, R152a in an R12 system. The molecular weight of r152a is only 62% of R12, so you would use only 62% the amount of R152 in an R12 system. But, if you change the condensor, and the volume of the system, you'll be doing some guessing. With R152a in my BMW system, ideal low-side pressure is ~15 psi and high side at ~175 psi. Those pressures are MUCH lower than with R134, and the compressor is working very easily and almost silently. Vent temp is 37F.



Side-tap for R152a cans:

 

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What refrigerant is in your car now?

Reine

You are confusing me, possibly a language barrier?

You state in post #15

"....I am using the Hydrocarbon replacement gas so thats why i am a little confusing....."

Yet in post #1 you say.

"....I converted it from R12 to R134...."

R134 is not a Hydrocarbon refrigiant, it is a haloalkane refrigiant see.
https://en.wikipedia.org/wiki/1,1,1,2-Tetrafluoroethane

Hydrocarbon based refrigiant are discussed here
https://en.wikipedia.org/wiki/HC-12a

So please state using the "R" number (ie. R12, R22, R-600a and so on.) the refrigiant currently in your Montreal.

Here is a company that sells hdrocarbon based refrigiants
Environmentally Friendly Refrigerant and Automotive Fluid Products - Enviro-Safe, Inc

Finally here are some links about conversion to hdrocarbon based refrigiants
Using Propane in Volvo AC - Turbobricks Forums
Higher performance Propane A/C: Here's how - Turbobricks Forums


Bye
 

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Discussion Starter #18
Reine

You are confusing me, possibly a language barrier?

You state in post #15

"....I am using the Hydrocarbon replacement gas so thats why i am a little confusing....."

Yet in post #1 you say.

"....I converted it from R12 to R134...."

R134 is not a Hydrocarbon refrigiant, it is a haloalkane refrigiant see.
https://en.wikipedia.org/wiki/1,1,1,2-Tetrafluoroethane

Hydrocarbon based refrigiant are discussed here
https://en.wikipedia.org/wiki/HC-12a

So please state using the "R" number (ie. R12, R22, R-600a and so on.) the refrigiant currently in your Montreal.

Here is a company that sells hdrocarbon based refrigiants
Environmentally Friendly Refrigerant and Automotive Fluid Products - Enviro-Safe, Inc

Finally here are some links about conversion to hdrocarbon based refrigiants
Using Propane in Volvo AC - Turbobricks Forums
Higher performance Propane A/C: Here's how - Turbobricks Forums

https://www.youtube.com/watch?v=AxZw7uCiOtw

Bye

Hi Milanoguy :)

I see that i missed to tell that i am using the Envirosafe Hydrocarbon replacement gas instead of the R134 and R12

Sorry that i confusing you all :)

Thanks for the links Milanoguy
 

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Hi, I am the novice with my Montreal and I need to help. How should I control the levers and controls when I want to cool or warm?
Thanks
JR
 
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