| Author |
Message |
Bill Sebestyen (Bill308)
| | Posted on Sunday, September 16, 2001 - 11:06 am: | |
Torai and Hebert,
Thanks for the excellent discussion and links. The compressor and mounting brackets were missing from my car at purchase so I have special concerns. The reason for its absence is unknown .
To sum up:
Refurbishment of the factory system, for use with R-12, is the conservative choice. All components are compatible. An A/C shop, using special equipment, should flush the system if it has been opened for a period of time. Hebert recommends the dryer and expansion valve should be replaced if the system has been open for a period of time (corrosion/contamination issue?). Mineral oil should be added prior to sealing the system. The cost of R12 and its future availability remains an issue.
RB-276 is an acceptable solution that is compatible with the York compressor and the rest of the factory components. Barrier hoses are not required. Unique fittings are required to preclude contamination with other refrigerants. The sight glass cannot be used to ascertain a system full condition. RB-276 is an azeotrope, a mixture of liquids that has a constant boiling point and thus cannot be separated by distillation (this means it may be topped off with little change to the overall mixture). An A/C shop, using special equipment, should flush the system if it has been opened for a period of time (corrosion/contamination issue?). Hebert would likely recommend the dryer and expansion valve should be replaced if the system has been open for a period of time. Mineral oil should be added prior to sealing the system.
R-406 is not compatible with Buna-N seals used in some York compressors so replacement with Neoprene seals is required. Unique fittings are required to preclude contamination with other refrigerants. R-406 will carry lubricant well, so it is desirable if long lines are present (as in a mid-engine car), and provides more cooling capacity. The requirement for barrier hoses is unknown to me. An A/C shop, using special equipment, should flush the system if it has been opened for a period of time. Hebert would likely recommend the dryer and expansion valve should be replaced if the system has been open for a period of time (corrosion/contamination issue?). Oil should be added prior to sealing the system.
R-134 appears risky. It is inexpensive and widely available so it is favorable if the system is leaky. R-134 likes a low compressor position (also aids compressor lubrication) relative to evaporator (308�s are high), short lines (lines are long in mid-engine applications), and a high side pressure switch. The A/C lubricating oil is different and the receiver/dryer needs to be changed to XH-7 or XH-9 types. The York compressor is likely to fail slowly. The requirement for barrier hoses is unknown to me. R-134 is especially sensitive to moisture in the system. System operating pressures are higher putting additional stress on components. An A/C shop, using special equipment, should flush the system if it has been opened for a period of time. Oil should be added prior to sealing the system. Hebert would likely recommend the dryer and expansion valve should be replaced if the system has been open for a period of time (corrosion/contamination issue?). Oil should be added prior to sealing the system.
If anyone has more to add or challenge, please feel free.
Bill |
Frank Parker (Parkerfe)
| | Posted on Sunday, September 16, 2001 - 8:05 am: | |
Scott, one reason NOT to convert is that R134 does not cool as well as R12. With air conditioning systems in Ferraris already weak, do you really want to make them worse? I say stay with the R12. |
Frank Parker (Parkerfe)
| | Posted on Sunday, September 16, 2001 - 8:05 am: | |
Scott, one reason NOT to convert is that R134 does not cool as well as R12. With air conditioing systems in Ferraris already weak, do you really want to make them worse? I say stay with the R12. |
Herbert Edward Gault (Irfgt)
| | Posted on Saturday, September 15, 2001 - 8:37 pm: | |
In order to flush a system you will need a flush gun or a machine to do it with a special solvent. I would recommend getting it done professionally as the equipment investment would not be worth it. |
Torai Madjid (Black5000s)
| | Posted on Saturday, September 15, 2001 - 6:48 pm: | |
Bill,
What happened to the old compressor? If a compressor shredded (metal dust in the discharge port), or there are contaminants like burnt oil, you have to flush. If you flush, remember to add the the recommended amount of oil to replace what resides in the evaporator, condensor, and receiver dryer (7 oz typical I think).
I think getting the leaks out and staying with R-12 carries least risk. A sniffer can find very low leak rates like a fraction of an ounce per year.
You get rid of moisture by evacuating the system for a long time. This is particularly important for PAG and POE oils. I pump down a system for 6 hr to a couple days. I have a millitorr guage, so I can see when the water is really gone.
Some think that R-134 leakage from non-barrier hoses used formerly with R-12 is much reduced.
FREE ZONE RB-276 is an alternative to look at for York Tecumseh compressor applications. It does not contain R-22. It does not have the higher head pressures that R-134 does.
The compressor does not need replaced to change refigerant. You may or may not have to remove the compressor to change the oil in it. You can often check or change oil in a York Tecumseh in place. R-12 (mineral) oil in the compressor should be replaced for R-134. The shaft seal may need changed in some cases, particularly for some York compressors and R22 containing blends like R-406.
My rationale for R-406 in the Countach:
The big windshield and inadequate A/C system makes you cook. I chose R-406 because:
- It provides better cooling output.
- The Sanden compressor is compatible.
- I do not want to tangle with changing oil type
- I do not want to worry about PAG or POE problems
- The Countach has a high mounted compressor and long lines.
- The Countach does not have a high side cutoff switch
My picks would be something like:
R-12 - Leak free system. No compressor, or seal incompatibility risk. No changes to system required.
R-134 - Inexpensive and readily available, invasive retrofit, slight performance reduction, requires additional work, risky in some cases. Incresaed system pressures.
Adequate A/C (slight performance reduction). low compressor position, compressor below evaporator, not a lot of hose/line length (good oil return to compressor). Requires oil and receiver/dryer replacement to XH-7 or XH-9 dessicant type. Requires stringient moisture control procedures. Favorable for incurably leaky systems. Requires high side pressure switch. Compressor failures are usually latent, not immediate. Do not mix with R-12. Remarked by some as being profitable for service trade.
R-406 - Non invasive solution for leakfree systems of inadequate capacity. May fail Buna-N shaft seal in some York compressors.
Works with R-12 oil. More cooling output than R-12. Leak free system (top off more difficult). High compressor position, compressor above evaporator, large hose/line length (R-406 carries oil well). No receiver/dryer or oil change required. Buna-N shaft seal in York compressors needs to be changed to Neoprene. Do not mix with R-12.
http://www.autofrost.com/
FREE ZONE RB-276 - Non invasive solution for systems incompatible with R-22. Does not require receiver/dryer or oil change. Do not mix with R-12. Near azeotropic, less composition change after leakdown than R-406.
http://www.heco.net/freezone.html |
Bill Sebestyen (Bill308)
| | Posted on Saturday, September 15, 2001 - 8:27 am: | |
Hebert,
Is there a special chemical and equipment required to perform a flush?
Bill |
Herbert Edward Gault (Irfgt)
| | Posted on Saturday, September 15, 2001 - 4:55 am: | |
If the system has been open for a while, I would get the system flushed, and replace the Drier and Expansion valve before installing the new compressor. |
Bill Sebestyen (Bill308)
| | Posted on Friday, September 14, 2001 - 9:57 pm: | |
Herbert,
Thanks for the timely input. I suspect staying with R12 is the wise thing to do. Do you have any tips for preping the system prior to fitting a new compressor and sealing the system?
Thanks,
Bill |
Herbert Edward Gault (Irfgt)
| | Posted on Friday, September 14, 2001 - 9:35 pm: | |
Actually R-12 prices are dropping. I have never seen a converted system work as well as the original. I can now buy 30 lb cylinders for $800.00 where as they have been as high as $1000.00. I will keep my car on R-12 as long as I can get the stuff. |
Bill Sebestyen (Bill308)
| | Posted on Friday, September 14, 2001 - 9:20 pm: | |
Torai,
I�m impressed with your breadth of knowledge on refrigerant chemicals and systems. I�d be interested in your recommendations for overhauling or upgrading a 308 A/C system.
Would you recommend staying with the factory system and R-12?
If the system had been unsealed for some time (say the compressor was missing and the lines left open but otherwise all factory pieces were still intact) what steps would you recommend to put this system back into operation?
If you were to convert the same system to another refrigerant, which one would you select? What other A/C system components would you replace and why?
Thanks,
Bill |
Torai Madjid (Black5000s)
| | Posted on Friday, September 14, 2001 - 6:52 pm: | |
Systems should not leak if they are right.
R134 molecules will leak faster then R-12. So will R406A.
R406A can be incompatible with some York, Tecumseh, and Chrysler RV-2 compressors, because the R-22 in it is not compatible with Buna-N seals. It has smaller molecules, so it will leak faster. Quite a few NOS Buna-N seals still are floating around.
Leakdown in 2 months is a gross leak. If you need to keep topping a system because of a leak, the oil is probably being lost too (it circulates with the refrigerant). The compressor will eventually fail.
Non barrier hoses formerly used with R-12 may leak less. PAG or ester oils may be incompatible with some seals in R-12 systems causing leaks. |
Torai Madjid (Black5000s)
| | Posted on Friday, September 14, 2001 - 6:39 pm: | |
see
http://server.ferrarichat.com/~ferrari/ferrarichat.com/discus/messages/112/2120.html
lots of discussion there.
Lots of hose length, and compressor mounted high/or A/C system design marginal: avoid R134. R134 demands a clean water free system. R134 related compressor failures are usually latent, not immediate.
R-12 or R406A may be better alternatives, and carry less compressor breakdown risks.
I hate compressor failures, because I hate cleaning the shavings from the system. |
Paul Sloan (Sloan83qv)
| | Posted on Friday, September 07, 2001 - 12:48 pm: | |
My compressor died so when I replaced with a new Identical York compressor I switched to 134, been 4 months with almost every day over 90 and it's still Ice Cold! |
Gene B. Radcliffe - 308 GTS (Brcbank)
| | Posted on Friday, September 07, 2001 - 11:51 am: | |
On the other hand . . . I thought of converting to R134 after reading Kelly and other's good experiences. But instead, being stubborn, I spent $20 and 30 minutes at www.escoinst.com for my EPA 609 license, $40 for two cans of R12 on Ebay, $5 for all new o-rings, and $30 for a can tap, hoses and pressure gauges. Total of $95 to stay original, get really cold and be ready to top off next year for $20-30. Just a thought. |
Greg Rodgers (Joechristmas)
| | Posted on Friday, September 07, 2001 - 8:07 am: | |
It is not necessary to convert to barrier hoses. It is recommended but not essential. Like stated previously a little may leak out. So topping off the system with one can of 134 per year isn't bad. The original compressor can be used if it is in good working order. 134a is a little higher pressure and that is why many do change their compressors to compensate. The drier needs to be changed. It is your filter and when switching from R-12 to 134a it is necessary.(it is in a high pressure liquid state) Many also change the high pressure blow-off valve to a high pressure cut-off switch as well. Again this isn't necessary but many change it as the 134a does operate at higher pressure and if enough pressure is built up the blow-off valve can open and release it. It is also an EPA idea. Changing the Drier, O-rings and a good flush to your system(gets out contaminants, oil, etc.) will be sufficient. I hope that I have helped in this matter. Please don't hesitate to contact me with any questions. |
kelly vince (Tofosi1)
| | Posted on Thursday, September 06, 2001 - 8:56 pm: | |
I look at it this way. I did everything that I posted on this site. I have had one problem, the 134a leaks out. I know I have a leak but it takes 2 months for it to all leak out. In the manual, it says that the R12 hoses do leak and that you MUST charge your system every year to replace the leakout R12. If R134a is $4.00 at Walmart, then I do not mind at all buying a can every month and loading it up. It takes about 5 minutes. I know it may cost over $200.00 plus the labot of removing the passenger side fuel tank to replace the R12 hoses with 134a. So, I am only going to do it when nessary.
My 2cents |
Bill Sebestyen (Bill308)
| | Posted on Thursday, September 06, 2001 - 8:44 pm: | |
Scott, Paul, and Steve,
I have lots of questions on this matter. I'd sure like to know what's really required and why. I can understand how some materials, like seals, can be incompatible. After a period of time they can dimensionally swell or chemically deteriorate and not function properly. Unless you know what the materials are and have materials knowledge, direct experience, or perform tests, how do you really know?
Paul and Steve - Did you replace the compressors and dryers because they needed to be replaced, (i.e. worn out or contaminated) or because they were incompatible with R134 and its companion oil? Were the replacement pieces new stock, similar to stock but specifically designed for R134, or completely different but footprint compatible?
Does anybody have long term experience running R134 with any stock components? How long have you used R134 and what has been your experience? Maybe by a process of elimination we can figure our what works and what doesn't?
Does anybody know what components are incompatible and why?
Are there any A/C experts on Ferrarichat who could discuss the issues and tradeoffs?
Thanks,
Bill |
Steve (Steve)
| | Posted on Thursday, September 06, 2001 - 7:57 pm: | |
I converted this spring after I replaced the compressor and receiver/drier. Works great on my 77 308 GTB. Did it myself and after discussing it with various people in the business they are pissed because they needed to get a certification and spend $4-6K for equipment for R12 and everyone is just dumping their R12 and filling up the system with R134. I have heard on no incompatability problems yet. Go for it. Steve |
Paul Sloan (Sloan83qv)
| | Posted on Thursday, September 06, 2001 - 7:19 pm: | |
I switched to 134 when I replaced the compressor and the only other part replaced was the dryer.(and maybe some o-rings)
This was done in June my a well regarded AC shop and my AC works extremly well, I live in FL and my 83 308 qv is a daily driver. |
Scott Gold (Scotttgold)
| | Posted on Thursday, September 06, 2001 - 6:03 pm: | |
Except the hoses!??? I was under the impression that everything was not(Dryer, expansion,..etc.) but the hoses were OK.
What is going on? |
Bill Sebestyen (Bill308)
| | Posted on Thursday, September 06, 2001 - 3:09 pm: | |
Scott,
I was told by a parts supplier that all components are compatible with R134 except the hoses. Bill |
Scott Gold (Scotttgold)
| | Posted on Thursday, September 06, 2001 - 2:42 pm: | |
Ok, unless someone has a real good excuse not to, I think I'm converting to R134. It just seems like the best alternative to R12 right now. It's really hard to find R12 around here.
The places I have been said they will convert me over to R134 and put in ester oil. But when I asked them, do I have to change the O-rings and dryer and expansion valve they said no. That struck me as odd. Every post on this site says yes I do have to change all these things. So whats the truth? And what is a fair price for this?
Thanks,
Scott
By the way, do they have to take the compressor out to do this conversion? |
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