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View Full Version : Using stock A/C system with 69 FB LS1 conversion



fast400
10-25-2007, 05:34 AM
I'm in the process of implanting a LS1 into a 69 Firebird. I want to retain the stock A/C system. The stock controls work with vacuum cans. Has anyone performed this conversion, or know if it works?

MonzaRacer
11-17-2007, 12:06 PM
Simply use the LS1 compressor and update your condenser and add on a good dual fan set up.
And dont forget using the newer compressor use a drier that is compatible with R134A and use the oil appropriate for the compressor.
You can use either pure methanol based air brake antifreeze or AC flush to flush the evaporator and associated parts.
Locate a NAPA that makes AC hoses and make sure all lines are made from Galaxy (or similar) R134A compatible hose. and use all the colored(ie not black) AC o-rings.
POA/STV and expansion valve systems have never gave me problems with converting.
But in my honest preference is setting the system up as a CCOT (cycling clutch orifice tube) or AAOT (automatic adjusting orifice tube) setup similar to stock.
The AAOT is a better setup as the orifice tube will self adjust as the engine speed changes. It releaves pressure load on the compressor and controls the flow into the evaporator making even older units like your 69 very efficient (heck most of the old systems would freeze you out anyway when properly serviced.
Good Luck
Lee Abel
AFTERMARKET PERFORMANCE

fast400
05-18-2008, 07:39 AM
Anyone have pics of stock AC conversion?

fast400
06-30-2008, 08:18 AM
Nobody has a pic of stock A/C in a LS conversion Nova, Camaro, Firebird...or anything..:help:

fast400
11-06-2008, 06:55 AM
I plan on using a Sanden compressor with the original evap(new) and new drier/condensor. I want to keep the original control levers. AC pressures will be PCM controlled. Has anyone done this?

fast400
11-17-2008, 05:50 AM
Anyone out there.....?

Twentyover
11-17-2008, 10:13 AM
So I'm not sure exactly what your questions are. There should be no problem using the vacuum controls to control door position

I work in automotive A/C, and I have no idea what you are referring to when you say A/C pressures will be PCM controlled. Are you talking about the PCM controlling the A/C clutch? And using a binary and/or trinary switch for compressor protection? Assume when you have A/C activated it will cause the PCM to trigger the engine cooling fan(s)

Think John Bzdell(sp?) has a factory A/C in is LS powered Monte.
http://www.montecarloss.com/ls1montecarloss/

You're using a fixed displacement compressor (good). Don't know if the factory A/C is TXV/STV system- if so, maybe want to convert it to a CCOT type- less moving parts, less stuff to go wrong. An A/C shop could provide the orfice tube and accumulator. Wiring shouldnt be a big deal. Note Bzdell is already a CCOT system.

MonzaRacer
01-30-2009, 09:29 PM
Like I said hook it up , wire stock wires back into newer compressor, use r134a compatable hose, flush evap core, use stock gm (what ever came in ac compressor in donor car)PAG oil usually PAG 150, and recharge after evacing for atleast 1 hour, oh and make sure new drier uses XH7/XH9 dessicant. Use guages and charge slowly, low side pressure should run 28-32psi on guages and if you use a cycling switch on low side it should not cut out if you rev engine up and hold it(like at cruise) I have converted many oe r12 setups and even if its a poa/stv or thermostatic control valve it should work fine if you have a good condenser core and proper fans to keep air flowing over it.
If you want to pic my brain give me a pm and Ill pm you my phone number and we can chat about it.

zman1969
02-25-2009, 05:24 AM
I am doing a LSx swap also but I've decided to go with Vintage or Hotrod air updating the 40 year old system that wasnt that effeciant in the first place. Electric actuators for the blend doors beats a 40 year old vacuum sytem IMO. If your doing the swap then update it! I think youll be happier in the end. I like the stock look but that went away with that new little aluminum gem weve put under the hood.:slap:

MonzaRacer
03-01-2009, 12:04 AM
Strange I have even converted my 71 Monte Carlo few years back the blower was not working and all I had was vent flow through , simply replaced the drier and hoses, still had old A6 compressor, just used Ester conversion oil aand it blew 38 degrees.
Darn must be too inefficient.
Hope to have R134A on my monza this year too.