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Anyone convert A/C to R134 by deleting EPR valve? #1518016
10/15/13 05:29 PM
10/15/13 05:29 PM
Joined: Oct 2003
Posts: 450
Belleville Il
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Dingmaster Offline OP
mopar
Dingmaster  Offline OP
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Joined: Oct 2003
Posts: 450
Belleville Il
Classic auto air states that converting to R134a you should remover the EPR valve and ad a themostate. Has anyone done this modification?

Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: Dingmaster] #1518017
10/16/13 12:47 PM
10/16/13 12:47 PM
Joined: Feb 2005
Posts: 174
Creedmoor, NC, USA
74Charger Offline
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74Charger  Offline
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Creedmoor, NC, USA
I considered it, but did not do it.

Instead i took my old EPR valve apoart, cleaned it, and got it working as it should. Manual says they are not serviceable.

My previous experience with 134-A conversion was a result in capacity loss, so I was less than impressed with conversion results.

My question for Classic Air would be, "Can an old-style RV-2 compressor clutch tolerate the cycling presented by the line t-stat?"

In the original configuration the EPR valve prevented the evaporator pressure from getting too low. This is the purpose of the t-stat Classic Air sells.

EPR valves are no longer available from the dealer in my area, and I have a reliable and knowledgeable MOPAR parts contact.

If you do the 134-A conversion, I hope you are satisfied.

Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: 74Charger] #1518018
10/16/13 12:53 PM
10/16/13 12:53 PM
Joined: Jan 2003
Posts: 27,389
Balt. Md
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383man Offline
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383man  Offline
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Balt. Md
The EPR valve on the Mopars controlled the evap pressure so it would not freeze up the same as Suction Throttle Valves did on Fords and GM cars. I have not seen any of them used since the late 70's and cycle AC systems came out. I would think the evap would freeze up without the EPR valve unless you put some kind of cycle control switch on it. Ron

Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: 383man] #1518019
10/16/13 01:30 PM
10/16/13 01:30 PM
Joined: Feb 2004
Posts: 919
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OLD318 Offline
super stock
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I did do the Classic auto air conversion to R134a...
I own a 70 Coronet 2 door hardtop with factory A/C.

The EPR is removed and they provide (at a not so cheap cost)
a thermostat to put into the system (external)...

The system works very well overall...
I had them redo every soft line,
pressure test and clean the evaporator and condensor
and they rebuilt the Air compressor removing the EPR and
replacing the oil etc... new clutch and I got a new
dryer (aftermarket) and new expansion valve (also aftermarket)..

Having done this...my recommendation is this:

If you have to have a stock appearance then obviously
rebuild/redo your original pieces...

If you can live with a non-stock look (and I've softened my stance
on this quite a bit, I used to be diehard stock)
then I think the better solution is to move to their compressor
upgrade package. it's lighter, more efficient and cheaper overall...
Granted it will not look stock...but you can install it and
have it look really good (IMHO)...

As far as the performance goes, I can't complain... I can get
36-38 degree discharge air on a pretty hot day... Even my newer
Ford can't do any better than that. It's usually around 40...

The external thermostat is installed per their instructions
I swear I almost never see it shut off... but on really hot days
it may not.... I can't say I've had any real issues with it
other than the thermostat line broke off and I had to replace it
(like $40.00 etc) which pissed me off...

Other than that they did a really nice job with the lines they look
exactly stock... the condenser looked like a brand new piece
as did the evaportator and heater core... I can't complain

Overall with shipping, freon and a couple of their thermostats
it was a little over $1000.00...

There is a gasket/insulation rebuild kit you can get for the
factory A/C box...it's absolutely worth the money...
But it's time consuming to disassemble/ clean/ refinish / and rebuild
that box....

Factory A/C cars can easily add $1000.00 and about 40 hours or
so to a restoration....If any of you have done it, I'm sure you
know by now that the 68-70 B-Body A/C box is a PITA to install by yourself!....


NOTE:

One of the problems I experienced with this overhaul/restoration was "expectations"...
I guess having spent a fortune on it I expected it to blow me out of the car....
We'll it didn't, but it's not because of the discharge air...
It's because the original factory blower motor circuit is by design LAME...
and my restoration even included and NOS blower motor!

As I learned from MAD Electrical...
All the voltage that goes to the blower motor, first goes through the fan switch...
then to a 3 step resistor and then to the blower motor...
So the voltage at the motor when running is not 12.6 volts.
It's more like 10.5. So your blower motor output vs a new car is very lame in comparison...

That has nothing to do with Classic Auto Air's rebuild.

You can bypass the MAX A/C full speed blower motor with a relay fairly easily.
But for the low/med setting, you're pretty much stuck with the
factory design...

I'm going to go the relay for the max setting but I have not done that yet...
I have done the alternator bypass and headlight relays from MAD
Electrical and they are EXCELLENT upgrades...
I also installed a relay for the A/C Compressor... from MAD...
Again an excellent upgrade...

That's all the news fit to print!

Best of luck to you either way...

Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: Dingmaster] #1518020
10/16/13 02:32 PM
10/16/13 02:32 PM
Joined: Jan 2003
Posts: 3,719
Space Station #5
471Magnum Offline
master
471Magnum  Offline
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Joined: Jan 2003
Posts: 3,719
Space Station #5
EPR should be removed and a thermostatic cycling switch installed.

That being said, RV2 compressors really weren't designed to have their clutch cycled.

Installing a Sanden-type compressor is really the best way to go.


-Jim

I can fix it... my old man is a television repairman.
He's got the ultimate set of tools... I can fix it.

Currently Mopar-less
Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: 471Magnum] #1518021
10/16/13 03:17 PM
10/16/13 03:17 PM
Joined: Apr 2007
Posts: 2,542
Calgary, Alberta Canada
a12rag Offline
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a12rag  Offline
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Joined: Apr 2007
Posts: 2,542
Calgary, Alberta Canada
On my 70 Sport Satellite, I got Classic Air to redo my lines and provide a new evaporator and heater core. I used a local shop to vacuum test and then fill the system. I asked them about the EPR valve, and they said, no, it should be ok. After getting the car back from them, on some of the hottest days we had (close to 35deg C = 90deg F), the system worked flawlessly - freezer cold !!!

As was posted before, a B body ac/heater unit takes a lot to rebuild and get back into the car. It was much easier to install, while the complete dash was out of the car !!! . . . pretty much figure I have 50 hours in that unit under the dash !!! . . .

Good luck with your car . . .

Cheers,

Mark

Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: 471Magnum] #1518022
10/16/13 03:40 PM
10/16/13 03:40 PM
Joined: Jan 2003
Posts: 27,389
Balt. Md
3
383man Offline
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383man  Offline
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3

Joined: Jan 2003
Posts: 27,389
Balt. Md
Quote:

EPR should be removed and a thermostatic cycling switch installed.

That being said, RV2 compressors really weren't designed to have their clutch cycled.

Installing a Sanden-type compressor is really the best way to go.




A cycling AC thermo clutch switch....that makes sense without the EPR valve.
I agree about the old Mopar RV2 comp as it takes a small V/8 to run the thing. They would really drag the idle down on my old 318 Scamp as it had no idle solenoid on that model and they would not help the gas milage. Newer style comp much better. Ron

Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: 383man] #1518023
10/16/13 06:24 PM
10/16/13 06:24 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
About to go away
Supercuda  Offline
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Posts: 14,889
up yours
Got an AC license so I'll keep R12 in my 65 Cuda. Never was impressed with the R134 conversion in my 87 Diplomat, yeah the outlet temps read 38ish but it never seemed to cool down like the R12 did.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: Supercuda] #1518024
10/18/13 10:14 AM
10/18/13 10:14 AM
Joined: Jun 2008
Posts: 1,818
Colorado
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denfireguy Offline
top fuel
denfireguy  Offline
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Joined: Jun 2008
Posts: 1,818
Colorado
Quote:

Got an AC license so I'll keep R12 in my 65 Cuda. Never was impressed with the R134 conversion in my 87 Diplomat, yeah the outlet temps read 38ish but it never seemed to cool down like the R12 did.


Spoiler alert: Thread theft in progress.
What about putting new style compressor onto system and retaining R-12? Is that possibile?
I have a horde of R-12. I am calling Classic today to ask them but I would appreicate any feedback from here.
Craig


2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado
Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: denfireguy] #1518025
10/18/13 12:33 PM
10/18/13 12:33 PM
Joined: Jan 2003
Posts: 9,394
Central,PA
62maxwgn Offline
master
62maxwgn  Offline
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Joined: Jan 2003
Posts: 9,394
Central,PA
R12 in this,just change compressor oil,no problems,and don't let Classic Air rip you off for a cycling switch !!

http://www.bpeusa.com/BPEac_cycling_switch.asp

7891934-62Eng.jpg (288 downloads)
Re: Anyone convert A/C to R134 by deleting EPR valve? [Re: 62maxwgn] #1518026
10/18/13 05:58 PM
10/18/13 05:58 PM
Joined: Jun 2008
Posts: 1,818
Colorado
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denfireguy Offline
top fuel
denfireguy  Offline
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Joined: Jun 2008
Posts: 1,818
Colorado
Quote:

R12 in this,just change compressor oil,no problems,and don't let Classic Air rip you off for a cycling switch !!

http://www.bpeusa.com/BPEac_cycling_switch.asp


I like that better. Keeps the double pulley.


2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado






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