Guest Posted October 25, 2002 Share Posted October 25, 2002 Hi everyone, I hope some one can help.I would like information on changing from stock a/c to a sanden 508 unit.I just got off the phone with vintage air and they only want to sell a complete unit for 1050.00.I really hoped I can bring the cost down. I know I would change compressor,POA valve,lines, condenser put not everthing on the firewall. Before I remount the a/c box on the firwall I want to make sure I rebuild or replace what I need. Any help or suggestion ? thank you Link to comment Share on other sites More sharing options...
Andreas Posted October 25, 2002 Share Posted October 25, 2002 I have heard good things about these guys: http://www.nostalgicairparts.com/ ------------------ 71 Monte 454 HO 5- Speed "FULMNTE" 86 Monte LS "The Gray Mouse" FOR SALE! 01 Camaro V6 Andreas' Monte Carlo Site Member NMCOA, FGMCC (Event Coordinator) ------------------------------------------ ------------------------------------------ "It ain't a car if it's not a Monte" Link to comment Share on other sites More sharing options...
Rob Peters Posted October 25, 2002 Share Posted October 25, 2002 I know some people will tell you that you have to change a bunch of parts to switch from R12 to R34. I had mine switched over in the spring and as of the last time I took it out a week ago, it still is blowing nice cool air. Now I will tell you exactly what the mechanic changed out on mine. NOTHING!!! The mechanic hooked a pump up to it and pumped out all the old oil and R12 and then charged the system with the R34. He then checked for leaks and found none. Again, some people have since told me it will not work without changing out a bunch of parts such as the ones you mentioned in your post but mine is living proof that it may not be necessary. I know, from previous posts about this, that others in the club have done the same thing as what my mechanic did. Rob ------------------ Go Car or Show Car, it doesn't matter, you are welcome here Link to comment Share on other sites More sharing options...
mjs-13 Posted October 26, 2002 Share Posted October 26, 2002 As stated above, you CAN change over to 134 and it does work as long as you change the oil in the compressor system. Now, the problems that can ultimately arise. The A/C hoses on are cars are NON vapor barrier. This is OK with R12 as it has a large molecule. 134 has a much smaller molecule and will eventually leak "through" the non barrier hoses on our cars. The fix is to update to late model barrier hoses. A hose supplier can make these locally. The POA valve on our cars is very inefficient way to control pressure and the compressor. A POA valve is not friendly to 134 and can cause problems in a 134 system. The best thing to do is replace it with a part from OLD AIR PRODUCTS in FT. Worth Tx. This part can be specified with fittings for 134 or R12 and its replacements. What is does is allow the system to operate like a late model system and "CYCLE" the compressor instead of using a POA valve to control freon flow based upon pressure. This is a MUCH better way to go. Cost is about $80.00 for the part. Other than that, make sure you always replace the dryer when you open the system and the small system filter. Instead of converting to 134, I have been using the substitues such a FREEZE 12 that require no oil or fittings changes on your original system. About $4.00 a can a O'Reilys Auto Parts. If you have the car apart, I would replace the evaporator and expansion valve, dryer and condenser. After 30 years of use or more importantly "non use", they are not "that" expensive and much easier if the box is off the firewall. Also do the heater core before it ruins your carpet. Remember, it also probably 30 years old. I would DEFINTELY replace the POA valve in any system. This makes the compressor last much longer and is much better way to go for compressor control no matter which refrigerant you use. The original system will work with 134 as a replacement. Rob Peters has proven that! Are the updates that can be made? YES! Do I use the updates I have outlined? Yes and I have chilly wind blowing all the time! ------------------ Mike Strinich Nashville, Tennessee 72 Monte Carlo Convertible Link to comment Share on other sites More sharing options...
Guest Posted October 26, 2002 Share Posted October 26, 2002 I want to thank for everyone that as replied.Put I have some more questions. MJS-13 you talk about getting a new poa valve from Old Air Products put with out doing alot of reseach are they on the web or what is the address? My whole a/c is in pieces and I want to do it right. I bought a polished sanden compressor off ebay and have street performance brackets. Vinage air tells me to run a Sanden 508 because it produces the most sq foot presure and since are monte are on the big side this compressor will work the best. The compressor is now sitting on the passenager side so I already plan to run new lines. I hear the 134 run at higher pressure and the stock unit will not hold up is this true.I want to do this a/c conversion right so if anyone can tell me were to get the best price on parts it would help. Other than r12 what is the next best thing and why? There is no since of rehanging the A/C box without doing right and not to have trouble down the rode. Thank you everyone for any help. Link to comment Share on other sites More sharing options...
mjs-13 Posted October 26, 2002 Share Posted October 26, 2002 ggMonte, I am not speaking of a "new" POA valve. I am speaking of a total replacement of the POA valve! This replacement fits in the same spot and has the same fittings as a POA valve. I assume that the only thing you want to change is the compressor to the Sanden as per your original post. Yes, the Sanden is a much better unit that is more efficient and takes less horsepower to operate. Since you will be making "new" hoses, make sure they are made with vapor barrier A/C hose compatible with 134. These are better hoses anyway. Now you can use "any" refrigerant you want! The POA valve is not 134 friendly. Replace it with the Old Air POA valve replacement part if you want to use 134. I replace the POA valve on all "my" cars so equipped without regard to the type of refrigerant I intend to use. A POA valve method of regulating compressor pressures in not a good method and its function is worse with the higher operating pressures required by 134. Again, the POA replacement part will allow the new compressor to "cycle" just as they do in New cars built today. If a POA valve were that good, GM would still use it! GM replaced the POA valve with an "accumulator" in most cars in 1975. This system is in use today! There are some guys who have found late model evaporators with a mount for an accumulator that will fit the GM A body evaporator box on the firewall. This would make the transformation complete to a late model system. Check on Chevelles.com by doing a search for this information. I have not done this as it is not necessary. Old Air advertises in Hemmings Motor news or just call them at 817 531 2665. Tell them Mike at McGee's Corvette Connection in Tn said to call. I have a Vintage Air "sure fit" system in one of my Corvettes and it works GREAT! I use 134 in that system. If you have questions, call me at 615 347 7459. Have fun!!! ------------------ Mike Strinich Nashville, Tennessee 72 Monte Carlo Convertible [This message has been edited by mjs-13 (edited 10-26-2002).] Link to comment Share on other sites More sharing options...
ejw71 Posted October 26, 2002 Share Posted October 26, 2002 Ggmonte, Do allthe things that Mike suggested. The product Freeze 12 is a EPA acceptable direct replacement for R12. No need to go to R134a. In a Chevy that the a/c wasn't run for 5 years I used Freeze 12. That was 2 years ago it works fine. Ed ------------------ '71 Black 406/700R4 '71 Sandalwood SS454 '71 project 2" chop/Green/346LS1/4L60E Link to comment Share on other sites More sharing options...
Guest Posted October 27, 2002 Share Posted October 27, 2002 I will try to call today or sometime this early part of the week. WHAT would be the best time for you? Thank you Greg Link to comment Share on other sites More sharing options...
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