New AC Question
 

I am going to replace most of my AC in my 1972 Luxury LeMans. I have a new dryer, wiring harness, compressor, hoses and muffler Assembly, POA Valve, and Expansion Valve. I am getting help from a friend to install everything but I do not have the equipment to vacuum and charge the system so I will bring the car to a local shop for that.

My question is this: Is it alright to have the belt and harness connected to drive it to a shop or will this damage the compressor?

Karl

:usa2:

If you want to be on the safe side, there is a two wire plug just behind the pulley that engages the clutch. Pull that and the compressor will not run. Go ahead and put the belts and stuff on.

George

Next Question.

This AC system has been open for an unknown period of years. I bought the car in November 2009 and the hoses, belt and wiring were gone already, leaving the condenser and evaporator cores with open hose fittings. What if anything should be done before connecting the new components and hoses?

Karl

:usa2:

R12 or converting? If converting, you would have to have the POA recalibrated, though guess you know that. Have to change to barrier hose too.

I would have both the condenser and evap core flushed and pressure tested. If you're doing R12, it would be a high dollar waste if it leaked. 134 operates at a higher pressure, again, pressure testing is a good idea.

You could always buy an aftermarket, high efficiency condenser, would get better performance overall that way, and pretty much wouldn't be able to tell it's not factory.

I went back and forth about what to do on the cutlass project, and ended up going 134 with a sanden compressor. Really happy with it, sure it will way out perform the factory setup. I did the line upgrade too, all screw on type fittings. Will charge it next weekend, looking forward to how it will perform. When it comes time to go over the LeMans, I'm going this route, not concerned about factory appearance.

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I have a brand new POA valve still in the plastic for r12. What exactly does it take to convert it to 134? As far as pressure testing goes wouldn't pulling vacuum on the system prior to charging handle this? Or is more pressure needed?

Karl

:usa2:

The POA calibration is best left to one of the specialty places in my opinion, I used Classic Auto Air. I liked using them because you can order individual parts, and not be tied to a whole system. This is from their' parts catalog:

http://www.classicautoair.com/Catalo...oryCatalog.pdf

MINIMUM REQUIREMENTS
• Change or rebuild the filter-drier.
• Drain the compressor oil and recharge with
134a compatible oil. (PAG or Ester Oil)
• Insure that the system is clean and free of
contaminants.*
• Replace or restore all rubber hoses with
barrier hose.
• Install 134a charge port adapters.
• Send POA Valve in to be calibrated.
• Charge with 134a between 70-80% of the
original R12 charge amount. (see page 44)
• Replace all o-rings with 134a compatible.
RECOMMENDED
• Install hi/lo pressure switch.

So, as you can see, it's a little more involved than just recalibrating the POA. I sent my evap core to them to be pressure tested, and sent my evap box to them, which they bead blasted, repaired, and shot with clear, looks mint. I also did the compressor & hose upgrade, was less than a replacement A6. The condenser is where you will get a big performance jump, and again, was less than shipping mine back and forth and having it cleaned and tested.

To answer your question, no, a vacuum pull isn't the same as pressure testing. And remember, 134 works at a higher psi too.

So if you choose not to convert, and keep most of what you have, and try to 'get by', you most likely will be going through it in a year or two again, and not have the performance you were hoping for either.

Do it right, or do it again, my motto. Cheaper to do it right the first time, or you might as well not do it at all.

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More I think about it, the least expensive way for you to go is R12, and to have a local shop clean, flush, and test your evap core and condenser. You can remove the evap core by splitting the box and removing the one half, don't have to take the rest of the box out of the car. You don't want to charge it with any contaminants in there, you can fry a compressor that way.

Most say to be safe is to remove the belt & clutch wire when running un-charged, because even though the clutch is disengaged, it will still drag and turn the compressor shaft.

It may be difficult finding a shop that has a R12 machine, fyi. A shop without one is just going to suck it down and fill it, something even a good mechanic could do at home. You can rent a pump, and buy a cheap set of R12 gauges, or even borrow a set.

FYI - an NOS OE POA is worth bucks.
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How does one know if their POA has been upgraded? I ask because my car supposedly had been changed from 12 to 134. Leaks miserably. It has the new hose for 134 fitting. What does the POA for an R 12 system look like vs a POA for R 134? The POA on my car has a screw adjustment on it that, with a 1/4 turn I noticed, will change when the compressor kicks on/off.
Thanks

Upgraded and calibrated are two different things, the POA is the same when calibrated, but to answer your question, The 'kick off' psi is higher for a 134 system. I guess it could be done with a set of gauges attached, but believe the internal seals need to be replaced. Best to send it off, and cheaper in the long run that way.

Your system probably leaks after changing to 134 because 134 uses a different oil, and that oil probably ate all the seals up. The o-rings/seals are green for 134.

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