hey everyone, I'm lookin for someone who is well versed in the knowledge of buick A/C systems, and would spare some advice to put mine back together - I have all of the parts except the expansion valve, which I am currently retreiving. the guy who owned the car before me ripped everything out, and stuck it in a box, all the parts I have refurbished to the best of my ability, and now I am ready to start work! 1. My car is a 71' skylark - which I know did not have superheat, but my car does not have the harness connection for the compressor clutch (someone must have clipped it off) - I have pulled the front end of the harness from a 72 skylark (which had superheat) - can I implant the new harness with a 71' compressor, or maybe the compressor I have is a superheat, and didn't come from my car (how would I tell???). 2. what's the life expectancy of a POA valve pulled from a 72 skylark? it has some surface rust in the neck, should I be worried about the internals??? 3. where do I put the expansion valve capillary tube/ bulb in relation to the evaporator core? 4. what kind of refrigerant should be used in this system? 5. realistically how many horses is this going to sap from my engine? I might not bother if I can't drag race my baby any more... 6. how tight should I torque all fittings to, and anything else that is a glaring red warning sign that I should be paying attention to???
I have a lot of experience with my 1970 Skylark and I have been in the HVACR business for the last 18 years and actually learned refrigeration theory woking on automotive AC before I got into HVACR. I like to help people and I hope I can help you. 1. What I'm going to say applies to 1970 and I'm not sure what the differences are but I'm pretty sure they're small if any. There's just one black wire that energizes the compressor clutch. It might be easier to trace it down in the harness and just attach a new length of wire. You can still use the harness from a '72 and bypass the superheat switch and fuse. If the compressor you have has a superheat switch, it can be bypassed. The superheat switch fits into the rear of the compressor just under where the lines bolt on and is held in by a snap ring. 2. Life expectancy of a POA valve is unknown! I have a working 37 year old one in my car that I bought used and I'm sure there are a ton of newer ones that are bad. I'd test it or have it tested before I installed it. They can be bench tested. You can learn a lot here..http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7567 "By the way...the tester is rather simple to make. All you need is a fitting to screw into the input(to simulate the evap). put an air nipple on it. Then take you manifold, put the low pressure hose on the low pressure port of the POA. Put the supply hose on the input of the fitting you made. Then take the high pressure hose and connect it to shop air supply of 60 lbs. Open the manifold. Listen to the POA to "click" and stablize. Read the low pressure guage." They can be tested on the bench without the evaporator or TXV. Making up the fittings is the hardest part. I used a PVC 3/4 male NPT to screw into the inlet of the POA. It's not a perfect fit but it did hold 60psi and I tested a few POA's with it. The pressure you're looking for is 28.5 psi. If you send me yours I'll test it for you. 3. The TXV sensing bulb is attached to the evaporator outlet with two clamps and is insulated with black cork tape. Make sure the surfaces are clean and attach it at 12 o clock. I'm sure you've seen the black blob of cork tape a million times. 4. Refrigerant, R-12 works best as that's what the system was designed for. You can still find it out there though it's not cheap. There are lots of alternatives out there and it seems like everyone has an opinion. I've used a few of them and they all seem to work fine. I like R-500 but that is tough to find and just about impossible to find in small quantities. If you choose R-134a you'll have to adjust your POA valve. That link above discusses that. 5. Power loss is about zero when the compressor is disengaged. You can figure on around 200 lbs added weight slowing the car down. Engaged, those A-6 compressors are HP hogs. Don't race with the AC on! 6. You're going to have a hard time getting a torque wrench on a refrigerant fitting. It's a feel thing. You can get an idea of how tight you need to go when you leak test. If you see bubbles, tighten till they stop to learn the feel. Smaller lines reqiure less torque. Replace all the o-rings and if you can, replace the hoses as well. You'll want to make sure you use the correct amount and type of refrigeration oil for the refrigerant you use and make sure the hoses and o-rings are all compatible with the oil and the refrigerant. The receiver drier must be changed. I like to leak test with nitrogen at 300 psi (only use your high side gauge for pressures over 150 psi) pressure with soap bubbles before I charge the system with expensive refrigerant. You can use pretty much any nonflamable dry gas to leak test. Helium, CO2 or dry shop air for example. If you're not using R-12, the exact amount of refrigerant that will work best is a guess. I'm sure I forgot to mention a lot but feel free to ask away.
this is incredibly incredibly helpful - I'll think up some more questions as I go along! - oh BTW I am going to post a picture guide to how I install this beast for future reference
I would also suggest a new wiring harness. Well worth the cash. Once stuff is ripped of 36 year old cars it all goes down hill from there.
Also on 71 the AC compressor connector comes out of the harness right with the coil wires. It is a double connector. it is one green wure with a doble connector haveing a short black wire with a ring terminal that is the ground that attaches with a screw to the middle of the upper ac bracket in 71. Make sure someone ddi not just tape it back on the top of the block.
i'm doing a manifold swap (my nice new aluminum TA performance stage 1) this weekend or sometime, and I will be dissecting the wiring harness to fix the rat's nest, and look for that wire... the superheat looks the same, but it has a dark green wire into a three way fuse block, one wire has a plug type connector that fits nicely on this "input" of sorts on the back of the compressor - the other wire energizes the clutch by going into the double connector, and the black ground comes out of it - same thing plus the fuse block three-way, and this plug connector - I wonder if it'll actually make some kind of difference if I just splice it in... provided that the guy clipped the original line...
Is there anyone that makes a complete AC rebuild kit, specificially designed for the year and model car you have?
