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AC Compressor Recommendation

Discussion in 'EEK! - Every Extended-K Car' started by dc8flyer, Apr 7, 2020.

  1. dc8flyer

    dc8flyer Well-Known Member

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    The AC compressor was going bad last summer causing a pull on the engine. I tried having it replaced this past week with not much success.

    The first rem compressor from AutoZone would not compress. The second one from NAPA (new) the shaft pulled lose.

    Where do you go to find something not made in China that actually works?
     
  2. Best Answer:
    Post #10 by AllanC, Apr 7, 2020
  3. valiant67

    valiant67 ...

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    I'm not sure how realistic this is, but I would seriously consider finding one of the later Spirit/Acclaim models built for R134a (1944-1995) and grab what you can from a junked car. Even if the compressor is no good, you'd have the brackets and hoses to mount a newer compressor designed for R134a.
     
  4. dc8flyer

    dc8flyer Well-Known Member

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    The AC was changed over to 134a about ten years ago. I loved the old R12. In less than three minutes on a hot summer day the car would be freezing cold.

    The 600se AC compressor will work with r12 or r134a. I'm not aware that they are different in that respect unless I'm missing something.
     
  5. AllanC

    AllanC Well-Known Member

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    I believe you are referencing the air conditioning system on a Dodge 600? If YES then the vehicle originally used a Chrysler built and designed C171 compressor. That is no longer made and the existing units have been rebuilt numerous times such that the rebuilds are a real "crap shoot". Also it was designed for R12 refrigerant and not for the higher operating pressures possible with R134a refrigerant.


    The 600se AC compressor will work with r12 or r134a. I'm not aware that they are different in that respect unless I'm missing something.[/QUOTE]

    R134a systems can achieve the same cold temperature levels as a R12 system. But the system has to have all components designed and matched to give this cooling level. Mix and mismatch components between R12 and R134a will result in less than desirable results.

    As mentioned the Dodge 600 used a Chrysler C171 compressor. Around 1991 Chrysler started to outsource and use a Denso compressor on its front wheel drive vehicles. This compressor used R12 refrigerant but was designed for conversion to a R134a system and higher operating pressure. If you could find the mounting bracket and idler pulley used with the Denso compressor for a 2.2 liter or 2.5 liter 4 cylinder engine, you could use an updated compressor. See attached image.

    If you decide to upgrade and use the brackets for a Denso compressor you will need the suction and discharge manifold used on the compressor. Rebuilt / replacement Denso compressors are NOT supplied with this manifold. Also the belt used is 1 inch shorter than used with C171 compressor.

    Denso Compressor R134a.jpg

    The real issue with converting an automobile R12 refrigerant system to R134a is the condenser. With R12 auto manufacturers typically used a very simple tube and fin type heat exchanger. It was serially flow which meant one large tube wound through the coil and exited. That would provide sufficient heat exchange for R12. But R134a had less heat capacity per pound mass of refrigerant versus R12. So the engineers had to design different heat exchangers with greater heat transfer but still be able to fit in existing, cramped locations in the engine compartment.

    The solution was to use parallel flow and serpentine condensers to give extra heat transfer but maintain overall dimensions. So if you want the air conditioning capacity associated with R12 in an upgraded system, you need to replace the condenser. It appears replacement condensers for a Dodge 600 have an upgraded design with parallel flow condenser.
     
  6. dc8flyer

    dc8flyer Well-Known Member

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    R134a systems can achieve the same cold temperature levels as a R12 system. But the system has to have all components designed and matched to give this cooling level. Mix and mismatch components between R12 and R134a will result in less than desirable results.

    As mentioned the Dodge 600 used a Chrysler C171 compressor. Around 1991 Chrysler started to outsource and use a Denso compressor on its front wheel drive vehicles. This compressor used R12 refrigerant but was designed for conversion to a R134a system and higher operating pressure. If you could find the mounting bracket and idler pulley used with the Denso compressor for a 2.2 liter or 2.5 liter 4 cylinder engine, you could use an updated compressor. See attached image.

    If you decide to upgrade and use the brackets for a Denso compressor you will need the suction and discharge manifold used on the compressor. Rebuilt / replacement Denso compressors are NOT supplied with this manifold. Also the belt used is 1 inch shorter than used with C171 compressor.

    View attachment 27545

    The real issue with converting an automobile R12 refrigerant system to R134a is the condenser. With R12 auto manufacturers typically used a very simple tube and fin type heat exchanger. It was serially flow which meant one large tube wound through the coil and exited. That would provide sufficient heat exchange for R12. But R134a had less heat capacity per pound mass of refrigerant versus R12. So the engineers had to design different heat exchangers with greater heat transfer but still be able to fit in existing, cramped locations in the engine compartment.

    The solution was to use parallel flow and serpentine condensers to give extra heat transfer but maintain overall dimensions. So if you want the air conditioning capacity associated with R12 in an upgraded system, you need to replace the condenser. It appears replacement condensers for a Dodge 600 have an upgraded design with parallel flow condenser.[/QUOTE]

    Great info! Thanks

    I started with the reman from Autozone with the 171 compressor. The product info says it will work with 134a. Not sure if they can rebuild that compressor type to withstand the higher pressure of 134a with better components or if it would simple be impossible to do.

    The new compressor they advertised uses the 590 compressor. Not sure if that addresses the 134a higher pressure or not.

    AC Compressor - Air Conditioning Compressor for Cars, Trucks, & SUVs | AutoZone (at https://www.autozone.com/cooling-heating-and-climate-control/a-c-compressor?filterByKeyWord=ac+compressor&fromString=search&isIgnoreVehicle=false&model=Ac )

    The other one we tried was from NAPA. It has the 590 compressor so hopefully it will work better with 134a. Unfortunately the pulley was not installed properly and wobbled.The last one of its kind is arriving tomorrow and hopefully this will be done.

    https://www.napaonline.com/en/p/TEM...tioning+Compressor&keywordInput=ac+compressor
     
  7. dc8flyer

    dc8flyer Well-Known Member

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    R134a systems can achieve the same cold temperature levels as a R12 system. But the system has to have all components designed and matched to give this cooling level. Mix and mismatch components between R12 and R134a will result in less than desirable results.

    As mentioned the Dodge 600 used a Chrysler C171 compressor. Around 1991 Chrysler started to outsource and use a Denso compressor on its front wheel drive vehicles. This compressor used R12 refrigerant but was designed for conversion to a R134a system and higher operating pressure. If you could find the mounting bracket and idler pulley used with the Denso compressor for a 2.2 liter or 2.5 liter 4 cylinder engine, you could use an updated compressor. See attached image.

    If you decide to upgrade and use the brackets for a Denso compressor you will need the suction and discharge manifold used on the compressor. Rebuilt / replacement Denso compressors are NOT supplied with this manifold. Also the belt used is 1 inch shorter than used with C171 compressor.

    View attachment 27545

    The real issue with converting an automobile R12 refrigerant system to R134a is the condenser. With R12 auto manufacturers typically used a very simple tube and fin type heat exchanger. It was serially flow which meant one large tube wound through the coil and exited. That would provide sufficient heat exchange for R12. But R134a had less heat capacity per pound mass of refrigerant versus R12. So the engineers had to design different heat exchangers with greater heat transfer but still be able to fit in existing, cramped locations in the engine compartment.

    The solution was to use parallel flow and serpentine condensers to give extra heat transfer but maintain overall dimensions. So if you want the air conditioning capacity associated with R12 in an upgraded system, you need to replace the condenser. It appears replacement condensers for a Dodge 600 have an upgraded design with parallel flow condenser.[/QUOTE]


    Do you have a link to a parts store for the condenser you mentioned above?

    Thanks
     
  8. dc8flyer

    dc8flyer Well-Known Member

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  9. ImperialCrown

    ImperialCrown Moderator
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  10. dc8flyer

    dc8flyer Well-Known Member

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    Found this thread from 2017.

    The A509 should work ok under the pressures of 134a if the compressor is new or in good shape. There are no parallel condensers made for these vehicles. Seems to be some debate over the 134a and r12 pressures being the same or 134a greater.

    C171 compressors were made for rear wheel cars and not front wheel cars. Not sure about that one though. Couldnt find any major advantages over c171 vs a590. Seems A590 is a newer production.

    R 12 to R 134 (at https://www.allpar.com/forums/threads/r-12-to-r-134.168157/ )
     
  11. AllanC

    AllanC Well-Known Member

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    The Spectra Premium 7-3344 condenser is parallel flow. Typically the item description will not include this information. You have to look at how the tubes are joined to a header tank at each end to identify parallel flow. See attached image.

    The partition barriers I have drawn in green are just for illustration. They are internal to the header tanks and partition the refrigerant flow. The illustration gives the general idea of the cross flow from side to side in the condenser. This gives about 30% greater heat rejection versus an R12 condenser that uses 1 tube serial flow through the unit.

    Spectra Premium Condenser Dodge 600.jpg

    If you follow this link and then look at accompanying compressors for the Dodge 600 you will see references to Four Seasons #57100 and #57104. 57100 is a remanufactured A590 compressor with tangent mount. 57104 is a remanufactured C171 with ear mount. Is the different mounting referring to the attachment of the compressor body to the engine bracket or to the means of attaching the suction and discharge lines to the compressor? I do not know. You would need to perform a visual inspection of the A590 and C171 to identify differences.

    ImperialCrown is correct in this statement. The mineral based oil used in R12 systems would tend to congeal and had no affinity for R134a refrigerant. The mineral based oil would not be picked up and circulated through the system to lubricate the compressor. So new synthetic refrigerant oils were developed. Chrysler R134a systems typically used a PAG 46 lubricating oil.

    If you convert an R12 system to R134a you should use an ester refrigerant oil which is compatible with any mineral oil residue and traces of R12 that could remain in a converted system.

    Now to add more confusion and frustration about refrigerant usage in automobile air conditioning systems, the U S EPA has mandated that all new vehicle production starting with the 2021 model year use R1234yf refrigerant in air conditioning systems. R1234yf does not have the longer term affect on climate change and the green house gas effect associated with R134a. R1234yf refrigerant is extremely expensive and has costs in the range of $100 per pound. Hopefully as time progresses and more chemical manufacturing comes online the unit cost will drop. R1234yf is about 5 - 10% less efficient that R134a.

    In January, 2018 the U S EPA started restricting the purchase of R134a. Containers greater than 5 pounds of R134a require a section 608 or section 609 license to purchase. This restriction would apply to 30 pound canisters of R134a. Small 12 ounce containers of R134a are currently exempt from any license purchasing regulation. But that could change at any time in the future. Also the U S EPA could institute taxes on R134a purchases to discourage future use.

    Point I am trying to make is that if you really want to keep the air conditioning system functional and drive the Dodge 600 for another 10 - 20 years (or longer) maybe you should upgrade to a more friendly R134a compressor. Just a thought on my part.
     
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  12. Dave Z

    Dave Z It's me, Dave
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    I should upgrade my Valiant...
     
  13. dc8flyer

    dc8flyer Well-Known Member

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    Just want to make sure this condenser is parallel since it has two different pictures.



    [​IMG]

    [​IMG]


    Reason I ask is this picture doesnt show the loops.


    [​IMG]

    Thanks
     
  14. AllanC

    AllanC Well-Known Member

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    This is a dual path flow fin and tube type condenser. It was the first attempt at improving heat exchange in air conditioning systems with the anticipated change to R134a refrigerant. See attached image.

    Dual Path Flow Condenser.jpg

    Remember that the "bean counters" are always around and directing what engineering should do to minimize cost. Having dual paths does give some improvement in heat exchange and does not increase manufacturing costs that much. But a parallel flow condenser is much better at rejecting heat for the same overall package size of the condenser. However more efficient heat transfer comes at a higher cost.

    Even though the dual path condenser might be lower in cost than the parallel flow, spend the extra money and get a more efficient condenser. You will get better performance and on those blistering hot days when you are moving slowly in traffic, the more efficient condenser will be welcomed.
     
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  15. AllanC

    AllanC Well-Known Member

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    Does your Valiant still have the RV2 cast iron compressor? From everything that I have read those older, mammoth, heavily constructed compressors convert well to R134a and can withstand the higher operating pressures.

    Here are two resources for converting or upgrading older, classic cars with air conditioning systems. You should be able to get some good information about how to convert an older system.

    Classic auto air & Vintage auto air.
     
  16. Dave Z

    Dave Z It's me, Dave
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    Yes, the original unit, but it has a nasty sympathetic vibration with the slant six. The resources didn't show up as links. My main problem is making it leakproof.
     
  17. dc8flyer

    dc8flyer Well-Known Member

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    I understand that but the Autozone site with The Spectra Premium 7-3344 shows those pictures which you say are dual flow. Before you said the 7-3344 was a parallel flow. Should I ignore the pictures and go with your understanding that the 7-3344 is a parallel flow?

    How did you determine the 7-3344 is a parallel flow? Did you reference a different source?

    Thanks again
     
  18. dc8flyer

    dc8flyer Well-Known Member

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    I called Summit racing and after ten minutes he came back and said it was parallel flow.

    Dont trust any pictures on AutoZone I guess.
     
  19. AllanC

    AllanC Well-Known Member

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    These reciprocating twin piston compressors are known for strange noises and vibration when they run. To get away from this and solve the leakage problem you will need to adapt a more modern wobble plate compressor.

    Ford had a similar issue with noise vibration on the York twin piston compressor it used in the 1960s - 1970s on its air conditioned vehicles. And they tend to leak refrigerant at the shaft seal.

    My error on the resources presented. One needs to put these names individually in the Google search and then find the appropriate link. I will correct.

    classic auto air -- Classic Auto Air - Air Conditioning & Heating for 70’s & Older Cars & Trucks (at https://www.classicautoair.com/ )

    vintage auto air -- Home - Vintage Air (at https://www.vintageair.com/ )
     
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  20. AllanC

    AllanC Well-Known Member

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    I went to the Autozone web site. I entered 1987 Dodge 600 with 2.5 liter engine for type of vehicle. I then searched for auto parts ==> Cooling heating and climate control ==> air conditioning ==> A/C condenser. One item is listed: the Sprectra Premium 7-3344 condenser. There is no image for the dual path condenser.

    I went to the O'Reilly auto parts web site. Again I entered the specific vehicle 1987 Dodge 600 with 2.5 liter engine. I went through the search for A C condenser and found only 1 condenser specified. It is labeled as a Murray climate control A/C condenser. Part number: 7-3344 which is the same as the Sprectra Premium unit. No image for a dual path condenser.
    So you must have seen the dual path at another site but NOT for your specific vehicle?

    Here is a link that shows in a schematic how a parallel flow condenser is constructed. Scroll down until you see the images of 2 condensers. The one on the left is a serial flow / serpentine flow with a single tube that traverses through the condenser.
    The one on the right is parallel flow and shows exactly how the Spectra premium 7-3344 condenser would function.

    AC condenser, air conditioning condenser || TechChoice Parts (at https://www.techchoiceparts.com/condenser )
     
  21. twankowski

    twankowski Active Member

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    Your OE compressor with the 2.5L is the Chrysler A590 (part number 4339456). Four Seasons aftermarket part number 58-100. Very common on almost all the FWDs of the 1980s.

    I've done five R-134a conversions over the past few years. Have used remanufactured compressors, new compressors, and even kept the OEM compressor on one car. I prefer remans in lieu of of the new Chinese castings and guts (but have a made-in-China GPD compressor on the '89 Sundance and it's been fine for 3+ years). It's a crap shoot at times. Rock Auto has the Four Seasons part for $179.99; there's a company in Kentucky selling remanufactured units on eBay for sub-$130.00:

    For Dodge Chrysler & Plymouth Reman AC Compressor & A/C Clutch CSW | eBay (at https://www.ebay.com/itm/For-Dodge-Chrysler-Plymouth-Reman-AC-Compressor-A-C-Clutch-CSW/174217928352?hash=item2890329ea0:g:tmEAAOSwrIxeaiHd )

    I've actually had very good fortune with all my conversions. I've always replaced the receiver-drier and expansion valve each time, suction and discharge lines from time-to-time, and performed a thorough system flush (pulled all parts besides the evaporator) on each component. Always used PAG-46 oil with a touch of dye, and of course new gaskets and O-rings.

    Have replaced condensers as needed, but prefer the OE tube-and-fin style. The Sundance has its original condenser, the '86 Daytona has an aftermarket parallel flow, and when I get to the '85 Reliant one of these days I aim to keep the original if possible. As a general rule, the OE styles flush well but the small tube sizes on the newer style are un-flushable. And they're also all Chinese...

    I get between 38-40 degrees at the outlets on all. Not R-12 good in my opinion, but good enough to me. In my experience with conversions, a clean, properly lubed, and properly sealed/evacuated system has always provided satisfactory results.

    On the '86 Daytona I installed (from eBay) a HD fan/shroud combo from a turbo car. It's a 4-blade setup versus the original 2-blade fan. I think it's a little better at pulling air through the condenser & radiator - especially when stopped in traffic. Could be all in my head, though.

    DC8Flyer: Your username reminds me of my return from deployment to Saudi Arabia in 1996. Came back from Prince Sultan Air Base through Rome and Shannon on an ATI Series -62 (combi) with the old P&W JT3Ds. What an airplane that was! Glad I got a ride before they all went away.
     

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