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5/6/04 1:51am - Original Message: 'Air conditioning concerns with lt1 into '76'
WRAITH
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Franklin Square, NY - USA

Vette(s):
' 76 Customized .Mid year rear window ( ' 67 style ). It has an '80 nose,'80 rear bumper , and a 76 hood . Also , I squeezed in a ' 94 Vette LT1 . Paint is a custom mixed BLACK with RED PEARL mixed in !

Joined: 4/18/2004
Posts: 116
Has anyone done the air conditioning system conversion successfully ? If so, did you update it to the new coolant system ( instead of the old type freon I meant)?
Were you able to use the lt1's a/c hoses, dryer, condensor, etc ? I completely forgot about the a/c system. So, any help would be appreciated, again. |thumb| |wink|
If you had to get custom hoses made, where did you get them from? On this , I am totally stumped. |ohwell|
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5/6/04 6:54am - Reply: 'Air conditioning concerns with lt1 into '76'
lumberjack
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COLUMBUS, MS - USA

Vette(s):
1972 Coupe; 350 4-speed with GM sidepipes; Classic White/Saddle

Joined: 1/11/2004
Posts: 331
Have not done an A/C conversion on a Vette, but have done the R-134 changeover on other cars. Because the new environment-friendly coolant requires a much higher operating pressure that the old R-12, the compressor, hoses and condensor have to be replaced with components that can handle the increased pressure. At the moment I can't recall definitely if the dryer has to be replaced also.

Discuss this with a qualified A/C mechanic. If you don't know of one, the shop I use here is outstanding.

Hope this helps.

John

|UPDATED|5/6/2004 3:54:30 AM (AZT)|/UPDATED|
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5/6/04 7:00am - Reply: 'Air conditioning concerns with lt1 into '76'
Big Fish
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Joined: 12/16/2003
Posts: 630
These people offer a "kit" for conversion. It comes with all the o-rings, oil, and gauge port adapters. They also have all the hoses available, but I don't believe it's necessary to change them unless they are leaking. I was successful in converting a friend's 70 to 134A, but opted for 12 in my car. http://www.oldairproducts.com/catalog/main_default.php
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5/6/04 12:40pm - Reply: 'Air conditioning concerns with lt1 into '76'
kstyer Lifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6410
You won't have to replace the hoses as long as you don't flush them. The old stuff inside creates a barrier for the 134a molocule, which is smaller than the R12 molocule. All new hoses should hold 134a, unless they are new old stock.

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On the "Tail of the Dragon"
(some day, no strike that, October 2008 it turned red, still in progress!)

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5/6/04 11:58pm - Reply: 'Air conditioning concerns with lt1 into '76'
WRAITH
Former Member
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Franklin Square, NY - USA

Vette(s):
' 76 Customized .Mid year rear window ( ' 67 style ). It has an '80 nose,'80 rear bumper , and a 76 hood . Also , I squeezed in a ' 94 Vette LT1 . Paint is a custom mixed BLACK with RED PEARL mixed in !

Joined: 4/18/2004
Posts: 116
Somehow, I had figured that there was a difference in components . My main concern was whether the hoses from the '94 lt1's a/c system would mate with the '76's condensor, and evaporator core. Would it not be more cost effective to just have custom hoses made , instead of trying to fit the lt1 to the '76 ? Another question would be : can the old condensor handle the the R - 134 ?
I might be needing that shops name and number John |thumb|

Bill ............ |headscratch|

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FEELS SO GOOD TO BE SO BAD
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5/7/04 1:05pm - Reply: 'Air conditioning concerns with lt1 into '76'
kstyer Lifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6410
The condenser and evaporator are not a problem. Although all other things being equal, those components are a bit larger in a 134a vehicle. You likely won't notice any difference.

You can have hoses made. I don't know if the existing ones will fit. Make sure you use O-rings and seals for the 134a, or they will leak.

____________________________________
On the "Tail of the Dragon"
(some day, no strike that, October 2008 it turned red, still in progress!)

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5/18/04 2:58pm - Reply: 'Air conditioning concerns with lt1 into '76'
76okievette
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norman, OK - USA

Vette(s):
Late Model 1976 L-48 Auto 100% Orginal

Joined: 1/26/2004
Posts: 8
I converted my 1976 L-48 to R-134a this year and all I did was get the conservation kit from Corvette America, it comes with what is called a VIR eliminator and a new compressor. I replaced the old dryer with the VIR eliminator, it hooked up to the same hoses and tubing, then flushed the system added the proper amount of oil and charged it with R-134a, it works fine and cools the car good. I did not replace any hoses and got the new compressor because the old one was broken not because I was converting. I am no expert but some folks make this conversation more diffucalt than it needs to be. Good luck.

GO SOOONERS
|laugh| |cheers|

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PC|I| |/I||B| |/B||COLOR=MAROON|
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5/18/04 3:27pm - Reply: 'Air conditioning concerns with lt1 into '76'
kstyer Lifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6410
They sure do make it harder than necessary. You conversion is great, you won't lose any efficency.
If the system was working, all that's really needed is to evacuate the old freon, install the other connectors, and fill it up. You do lose a bit of cooling this way, but most people won't notice. When I get that far I will just change valves and evac and fill. If I'm not happy it will be due to the VIR not operating properly, then I'll do the same conversion you did.

____________________________________
On the "Tail of the Dragon"
(some day, no strike that, October 2008 it turned red, still in progress!)

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5/18/04 10:17pm - Reply: 'Air conditioning concerns with lt1 into '76'
lumberjack
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COLUMBUS, MS - USA

Vette(s):
1972 Coupe; 350 4-speed with GM sidepipes; Classic White/Saddle

Joined: 1/11/2004
Posts: 331
I stand corrected.

Thanks. |thumb|

John
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5/19/04 1:19am - Reply: 'Air conditioning concerns with lt1 into '76'
anips
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 783
I believe if you are going to switch to a late model G.M. compressor and tie into the C-3 evap. and conds. you have to make new lines with a pressure switch,new dryer-rec.,
flush system, 134 compressor oil change from R12 oil, new shrader valves. For a "straight freon conversion" you guys have it handled, I did my chev truck that way and it works well, but for the vette I'am going for the late model coversion,takes less horse power but a little more money

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5/20/04 12:22am - Reply: 'Air conditioning concerns with lt1 into '76'
kstyer Lifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6410
Actually Lumberjack, you are correct. By nature of the beast, 134a DOES operate at higher pressure than R12. But it is not enough to damage components, unless they were already about to go. But sometimes that is the case.

And that does account for the loss of efficency with 134a. It's normally a 5 to 10% loss. By changing switches and controls, you optimize the system for 134a, and it works a bit better. But it works fairly well without changing them. If you switch the restriction device (VIR, expanansion valve, orifice tube) you can gain some efficency there as well.

If you change the restriction device, and change the sensor/switches, you will lose almost nothing in efficency. There will still be a very slight loss due to different size of the evaporator and condenser used with 134a. They are slightly larger by design when the system is designed for 134a.

It is always recommended that you replace the dryer anytime you open the A/C system. But if the system does not have particle contamination, evacuating the system for a longer period of time will remove the gas and moisture contamination. Then you don't need to replace the dryer.

Ecavuating the system involves connection a vacuum pump and pulling all gasses and moisture out of the A/C system.
You know all the moisture is out when you stop pulling vacuum, and the vacuum does not raise more than about 2" of vacuum. If it rises to 0, there is a leak. But if it raises and then stops, there is moisture in the system. Water will boil at 40 deg F if in enough vacuum (pressure less than atmosphere). So it boils and evaporates, the vapor reduces the vacuum, when the vacuum drops enough to stop the evaporation process, the vacuum holds at that point. The more moisture, the more the vacuum is lost before it stops.

If you just replace the R12 and don't open the system, you won't know if there is particle contamination. SO you won't know. Too much will clog the filter in the dryer. You develop a restriction in the dryer, the system won't operate much, if at all. The dryer will be hot at the inlet and cold at the outlet, and you'll know it's clogged.

|UPDATED|5/19/2004 9:22:06 PM (AZT)|/UPDATED|


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On the "Tail of the Dragon"
(some day, no strike that, October 2008 it turned red, still in progress!)

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7/15/09 11:11pm - Reply: 'Air conditioning concerns with lt1 into '76'
VetteFantzy77
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Vette(s):
77 corvette

Joined: 7/15/2009
Posts: 4
I have a early 77 corvette,AC system is open and i would like for it to work again.I want to convert over to R134. I have put on new hoses,and a compressor which is ready for R134. What else do i have to change. Do i have to put a new AC VIR? Or can i use something different then the old VIR,as I'm finding those are hard to find,and when i do they cost alot. Will i ruin my new comprssor if i try to use the old VIR.
 
Thanks Suz
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