Author Topic: Factory AC upgrade from R-12 to R-134a?  (Read 9107 times)

67L48

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Factory AC upgrade from R-12 to R-134a?
« on: August 10, 2007, 10:08:01 PM »
Not sure if this is a restoration, maintentance, or mild modification question, so I posted here.

I have the original AC in the car.  I had it charged in 1990 with R-12 and it worked fine.  Sometime between 1992 and 2000, the car lost the charge.  R-12 is around $100 a lb over here, so way too expensive.  However, I'd like to use my factory air.

Instructions online make it seem really easy.  Attach a filling adaptor, drop some new oil in, drop 3-4 12 oz. cans in. Done.

Is it really that easy?  Should I be concerned about anything?  Don't want to ruin any of my factory components.

Thanks.

67L48
1967 Camaro SS 350
PG, factory air, console, fold down rear seat, PS, PB, butternut yellow, #s matching, original manual/warranty/POP, <60K miles
Northeast Iowa

tom

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #1 on: August 10, 2007, 11:02:28 PM »
To charge AC right you need should evacuate the system, and use a set of gauges to measure the charge. However I have seen (not tried) at the Englishtown NJ swap a vendor that sells what he claims is compatible refrigerant at a very reasonable rate. I think it was less than $10 a can. Back in the day we often charged a system with a couple of cans of r12. It usually worked well, and the stuff was a buck or two a can. I should have stocked up.

Tom
69 X11 Z21 L14 glide
looking for a 69 export model (KPH) speed
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lakeholme

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #2 on: August 11, 2007, 06:17:30 PM »
Had mine done at my favorite shop three years ago --for the exact reason that Tom suggested: "to get a properly measured charge, check for leaks, etc."  (And I didn't want to damage my original AC either.)  Didn't take long (Of course, he has done it before!) and looked pretty much like you described it.  The only other advice he gave me was to run it every now and then to keep it "lubricated".  I have... it has held charge... and will freeze you out of there in about three minutes. 

Would you please post pictures of your AC in the motor well and around the radiator support? 

Phillip, HNR & NCR-AACA, Senior Master, Team Captain, Admin.,
Spring Southeastern Nationals chair, AACA National Director

Mark

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #3 on: August 12, 2007, 12:22:02 PM »
If your going to use R134 you need to replace the dryer with one thats designed for R134, you need to remove your compressor and drain ALL of the oil in it as the PAG oil used in R134 equipment is not compatible with the mineral oil used in the older systems.  Refill the compressor with PAG oil, (not really sure how much it takes)  You should also flush the rest of the system to get any remnants of the oil and refrigerant out (but I didn't do that an mine works fine).  After that you need to draw a vacuum in the system to get any moisture out and hold that vacuum for at least an hour although longer is better.  After that you just need to add 54 oz (give or take) of R134 to the system and you should be good to go.  Run the car at about 2000 rpm with the controls on max A/C and fan on high.  You want the low pressure side to be around 34 psi and the high up around 250 psi (but this varies due to air temperature)  Once you get up to 48 oz, go slow and watch the sight glass on the top of the dryer for air bubbles.  Once the air bubble stop your full.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

RAfbody

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #4 on: August 12, 2007, 02:39:38 PM »
On my 67 camaro the lines are not high pressure fittings, they use hose clamps.  Would this be a concern woth R134?
Russ

Mark

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #5 on: August 13, 2007, 04:16:49 PM »
No, operating pressures are roughly the same between R12 and R134 and is controlled by the thermostatic valve, the POA valve and the ambient temperature outside.  R134 would like to see about 29 psi on the low pressure side to give you the same vapor pressure that R12 will give you at 34 psi.  Remember your POA controls the low pressure setpoint, so it will try to maintain around 34 psi in the evaporator which will prevent the R134 from getting as cold as the R12.  In either event the difference in operating pressures between the two is insignificant.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

KurtS

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #6 on: August 14, 2007, 02:24:39 AM »
I agree that you're supposed to replace the dryer and purge the oil from the system. But I know of several people that didn't and haven't had problems. Some systems may be more sensitive to the issue than others.  YMMV.....
Kurt S
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67L48

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #7 on: August 14, 2007, 02:38:14 PM »
As I've looked into it a bit more, I think I'll just hold off.  Some people swear that it's plug and play with the $30 kit you get at wal-mart.  Others claim that it's a professionals-only job that requires full purging of the system, changing of O-Rings, etc.  If I had a 1992 Camaro, I'd take my chances.  With the 67 and factor AC, I think I'll hold off.  Thanks for the comments.

67L48
1967 Camaro SS 350
PG, factory air, console, fold down rear seat, PS, PB, butternut yellow, #s matching, original manual/warranty/POP, <60K miles
Northeast Iowa

tom

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #8 on: August 14, 2007, 05:39:20 PM »
If I make it to the fall swap at English town, I will get some info on the "r12 compatible" refrigerant the vender sells there. I can't vouch for quality, but he has been attending for several years. If the stuff was real bad, I would expect him to have disappeared by now.

Tom
69 X11 Z21 L14 glide
looking for a 69 export model (KPH) speed
o

tom

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #9 on: September 10, 2007, 04:28:26 PM »
Found the handout from the 'compatable' freon vendor. here is a scan version.

Tom
69 X11 Z21 L14 glide
looking for a 69 export model (KPH) speed
o

67L48

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #10 on: September 13, 2007, 06:22:55 PM »
Very interesting.  I think I'll open a new topic asking about this:

http://www.es-refrigerants.com/products/w/id/310/t/alternate-ac-recharge-kit/details.asp

67L48
1967 Camaro SS 350
PG, factory air, console, fold down rear seat, PS, PB, butternut yellow, #s matching, original manual/warranty/POP, <60K miles
Northeast Iowa

dougrmac

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Re: Factory AC upgrade from R-12 to R-134a?
« Reply #11 on: September 17, 2007, 05:54:09 PM »
If I am not mistaken, this "new" stuff is butane or propane or something along those lines. I seem to recall a discussion about it a few years ago on the camaros.net website. I don't know about you but I would think twice before filling my AC system with it.

Doug