#1  
Old 04-10-2020, 03:09 PM
crustysarge crustysarge is offline
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Default 70 Lemans LS2 swap AC Help

I have a 70 Lemans Sport that I am currently working on in Italy. I have swapped a 2005 GTO LS2 and am working on the AC right now. I have the '05 GTO stuff including the condenser and lines etc... The Lemans has factory air. The project started about 8 years ago but was put on hold for various reasons so the work was done back then.

This is not a show car. I cleaned the Lemans evaporator and reinstalled with a new expansion valve for R134. I had hoped on being able to utilize components from both cars to make it all work. I have a new 4 Seasons R4 compressor (PN 58941) that was bought for a 92 Firebird and never used. I decided to mount it on the LS2 with the Holley bracket kit and not spend money on another compressor at the time.

The donor GTO had a Ron Davis radiator and I have it with the fans and evaporator. It all mounts nice clean on the radiator tabs but has issues as the AC lines are on the driver's side and they hit on the Lemans rad support so I would have to modify it some. I also have the Lemans stock condenser and parts.

So, I am at a crossroads now to figure out the best way to make all this work. The car is WAY under budget as I sold a bunch of the GTO stuff and the 400 from the Lemans. I have considered a Vintage Air kit and rip out all the stock stuff. The interior is out of the car right now, including the dash so it would be easy. Only issue is getting the stuff over here.

IF I decide to keep the stock layout and reinstall the old condenser with a new drier what about the POA? Am I fighting a losing battle using the old stuff on 134? I see issues like how much oil should be added. I can buy a new condenser if needed as I think the stock Lemans might not be up to 134. I can do the vacuum and charge as I have equipment. I can get lines made no problem.

Give some ideas and your thoughts on how to proceed.

  #2  
Old 04-10-2020, 05:02 PM
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Scott65 Scott65 is offline
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You may wanna ask a moderator to move this to the non Pontiac motors in Pontiacs section. There are people with experience with what you're doing there. And you'll catch a little less grief from the purists there. Good luck

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  #3  
Old 04-12-2020, 11:52 AM
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LATECH LATECH is offline
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Well, to begin with, you have posted in the correct forum.

Secondly, I hope you and youre family are OK inthe midst of the pandemic. I hope that Italy recovers , as the rest of the world of course. Its sad what has happened.

OK. here we go.

The system on your 70 is a POA with expansion valve.That system used an A 6 compressor. This compressor has a crancase that is designed to hold around 6 ounces of oil. The Expansion valve , if you look closely , has an extra line coming from it that hooks to the POA valve that allows for circulation of any refrigerant oil in the rest of the system.
The compressor of POA system is made to run continuously and the POA regualtes the flow to accomplish temperature and to keep from Ice ing the system/evaporator.

So you have an R 4 . Not a real good choice. They arent the best of compressors.

I would recommend you going back to the v 5 harrison that was on the LS or get a sanden conversion kit.

Another issue to think about is the POA valve. It too, will need to be adjusted to work optimumly with R 134a.Its a small adjustement, but makes a substantial gain if efficiency as far as duct temps are concerned.

It will most likely provide a high level of dissapointment for you ,if you try to hook it up and expect good functionality.

The vintage air factory sure fit 564484 looks like a very good solution.It will allow you to clean up the engine bay nicely, it has modern more functional controls , plug and play.R 134a expansion valve and it is configured to perform well in its setup as research has been done to assure this. No guess work.

Unless you have a Very good A/C guy where you are, the vintage air is probably the best solution.

Now , if youwant OE appearance that can happen , but it will take some tenacity to get there.

  #4  
Old 04-12-2020, 11:55 AM
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LATECH LATECH is offline
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Here is a quick video about the POA adjustment...

https://www.youtube.com/watch?v=B95_q7Z8DIE

  #5  
Old 04-12-2020, 12:35 PM
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Scarebird Scarebird is offline
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The VA solution does indeed clear up the firewall but your room in the dash goes away. Also, their mounting system for the box was bad enough I made a run of brackets to replace them. You may want to hybrid the cooling ducts as VA provides a bunch of 2" flex duct - far from optimal flow wise.

http://forums.maxperformanceinc.com/...=718107&page=6

Starts at #108


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  #6  
Old 04-16-2020, 08:13 AM
crustysarge crustysarge is offline
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Thanks guys. I am still studying the whole thing out. The R4 has to do for now. It is a brand new (not rebuilt) for a 92 Firebird that was left on my doorstep, long story. At the time I made the choice to buy the Holley LS brackets so I really don't want to go back and spend $200 for Sanden and $200 for brackets.

My current plan is to eliminate the factory POA and replace with $100 "tube" with fittings on it. Although I have cleaned the stock POA and reset it to 26PSI I might try running it like it is but given the fact I need to cycle the R4 compressor and plan on using the trinary setup it might be better to eliminate it. Here is link to new tube.

https://www.oldairproducts.com/produ...122575-c157490

Then buy a generic $60 condenser (15"x27") that has #6 and #8 outlets. Get a universal drier and buy fittings from RockAuto and hoses as needed and get crimped at local hydraulics shop. I will use a trinary switch at or on the drier and not use the binary in the above POA replacement tube. I can vacuum and charge. Just need to do come with idea on how much oil to put in, The R4 supposedly has 3oz from factory. I figure 2oz for stock evaporator and 2 more for the condenser and maybe 1 or 2 for the drier/lines so 8-9oz total and cross my fingers.

One thing I am trying to figure out is what the thread/fitting sizes are on the POA valve. I lost my pitch gauge and don't have a fitting to work.


Last edited by crustysarge; 04-16-2020 at 08:23 AM.
  #7  
Old 04-16-2020, 07:18 PM
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LATECH LATECH is offline
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Look here

https://frankspontiacparts.com/usedparts/gtoparts.htm

about 1/3 of the way down the page is the tube you need for the POA

Remember the POA system was designed to run the compressor all the time. The "Tube" conversion is for an R4 and has a cycling switch.

  #8  
Old 04-16-2020, 07:48 PM
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hgerhardt hgerhardt is offline
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Quote:
Originally Posted by crustysarge View Post
.....
Then buy a generic $60 condenser (15"x27") that has #6 and #8 outlets. ....
Good move installing a parallel-flow condenser. Those work much better than the original round-tube units with R-134a.

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