Stock air conditioning with LS swap

[clinebarger]

Originally Posted by eagleuh1

Old thread, but worth a try. What condensors is everyone using? I'm running a 2005 5.3 with truck compressor, modified 68 evaporator with white GM orifice tube installed, and accumulator, and the 68 condensor. I have it running with the transduser to control fan on and off, and a low pressure cutout switch in the compessor suction line. Its a little wimpy on the cooling. Thinking about getting a newer condensor or putting a fan on the original condensor.

Running a R-12 condenser with 134a refrigerant hardly ever works right.....Without ALOT of airflow....Two good sized high CFM fans behind the radiator

Installing a fan in front of the condenser will restrict airflow at highway speeds.

Find the biggest 134a "parallel flow condenser" you can that fits your truck.

Keep the "fin & coil" condenser...And change to R-12...Getting all the PAG oil out will be very important though.

[Daaaanz67]

Hey clinebarger getting that pag oil out of the compressor will probably be almost impossible as the components inside will still be coated. What oil would one use to refill to be compatible with what's left over inside the compressor? My system was the ARA under dash which was the dealer add on I think my truck is a 69c10 ls conversion. Also when I reinstall this unit should I trigger one or both fans to come on while the a/c is engaged gonna keep it r12 I think or should I go 134? Oh yeah my motor is 06 ls truck motor and compressor thanks
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[clinebarger]

Originally Posted by Daaaanz67

Hey clinebarger getting that pag oil out of the compressor will probably be almost impossible as the components inside will still be coated. What oil would one use to refill to be compatible with what's left over inside the compressor? My system was the ARA under dash which was the dealer add on I think my truck is a 69c10 ls conversion. Also when I reinstall this unit should I trigger one or both fans to come on while the a/c is engaged gonna keep it r12 I think or should I go 134? Oh yeah my motor is 06 ls truck motor and compressor thanks
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PAG OIL (Polyalkylene Glycol) Refrigerant oil made for HFC R-134a systems CANNOT tolerate even minute amounts of chlorides...It will "destroy" any PAG oil thats in the system. Chloride is an ingredient in R-12.

Getting as much PAG oil out as possible....Draining the compressor, Replacing the dryer, & flushing the condenser & evaporator will go a long way. Whatever PAG thats left will "stick" to any aluminum surface it can find....as a black greasy film....Not ideal but doesnt really matter.

R-134a will NOT hold in a ARA unit....They have "flare" type fittings.

[Daaaanz67]

Then refill compressor with what type of oil
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[clinebarger]

Originally Posted by Daaaanz67

Then refill compressor with what type of oil
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Mineral Oil http://www.oreillyauto.com/site/c/de...2726&ppt=C0050

[Daaaanz67]

Thanks looks like enough to put some in and re drain. How much should that compressor hold.
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[clinebarger]

Originally Posted by Daaaanz67

Thanks looks like enough to put some in and re drain. How much should that compressor hold.
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Most of the underdash units take 4-5 ounces....Total system capacity.
I havnt seen any 525 mineral oil in smaller bottles.

I change the oil in my vacuum pump with it...So it's never a waste.

[MB Customz]

Originally Posted by TR65

Short-T,

I brazed that adapter into my high pressure line today and fabricated the compressor block. Looks like it will work OK.

TR

I'm finishing up an 82 with an 03 dbw truck 5.3 /4l60e and looking for help with the 03 high pressure switch to turn fans on with ac. Fans already working wired parallel but how do I get them coming on with the a/c. Any advice or links would be greatly appreciated. Thanks in advance to anyone who might be of assistance

[MB Customz]

[QUOTE=MB Customz;7333025]I'm finishing up an 82 with an 03 dbw truck 5.3 /4l60e and looking for help with the 03 high pressure switch to turn fans on with ac. Fans already working wired parallel but how do I get them coming on with the a/c. Any advice or links would be greatly appreciated. Thanks in advance to anyone who might be of assistance.

[Andy4639]

I used all the factory AC boxes but upgraded everything to 134A products. The air system system looks pretty much stock.

[TR65]

MB,

Check out my thread. Should be similar to what you have.

http://67-72chevytrucks.com/vboard/s...d.php?t=468107

I use the stock pressure sensor and the ECM to control the fans according to the high side pressure, so either none, one, or two fans come on as needed.

TR

[homemade87]

Originally Posted by MB Customz

I'm finishing up an 82 with an 03 dbw truck 5.3 /4l60e and looking for help with the 03 high pressure switch to turn fans on with ac. Fans already working wired parallel but how do I get them coming on with the a/c. Any advice or links would be greatly appreciated. Thanks in advance to anyone who might be of assistance

MB , Heres some info on my 82 on the trinary switch when I was doing mine . I used the stock comp in the stock location with the Doc blocks comp adapters .http://67-72chevytrucks.com/vboard/s...hlight=trinary

[67chevy1series]

I know this is an old thread but I don't want to make another thread since this is already on the topic. IBread through this and noticed everyone here was talking about using as much of the factory 67-72 AC boxes with the factory EFI LS motor and original compressors to the LS series motor. But for me I'm not running the stock/factory Intake and fuel injection or computer, I have a 67 with factory AC and At first I will run my engine carburated, (yes I know it's quite possibly the stupidest thing to do to an engine which is already fuel injected) I'm looking to find out how to hook up the factory AC of the 67, to the my 2002 5.3 from a silverado. I'm open to switching evaporators/condensor/reciver dryer to other units as long as they fit in the evaporator box and on the radiator support with little modifications, I would like to run 134a instead of r-12 and I know as of 1990 you need a low and high pressure switch so the system does not vent refrigeration out. Im also willing to getting a different AC compressor and bracket if there is one that can be used better or easier with the 67 then the one I currently have. I'm having some problems fitting the AC compressor bracket to the block with my motor mount plates as they stick out further forward, I was thinking about clearencing the bracket but I don't want to structurally compromise the bracket, what are your guys thoughts? I suppose there is the high mount AC option as well, but I do like how the compressor is tucked in out of the way with the low mount.

[67chevy1series]

Ttt

[Andy4639]

Originally Posted by 67chevy1series

I know this is an old thread but I don't want to make another thread since this is already on the topic. IBread through this and noticed everyone here was talking about using as much of the factory 67-72 AC boxes with the factory EFI LS motor and original compressors to the LS series motor. But for me I'm not running the stock/factory Intake and fuel injection or computer, I have a 67 with factory AC and At first I will run my engine carburated, (yes I know it's quite possibly the stupidest thing to do to an engine which is already fuel injected) I'm looking to find out how to hook up the factory AC of the 67, to the my 2002 5.3 from a silverado. I'm open to switching evaporators/condensor/reciver dryer to other units as long as they fit in the evaporator box and on the radiator support with little modifications, I would like to run 134a instead of r-12 and I know as of 1990 you need a low and high pressure switch so the system does not vent refrigeration out. Im also willing to getting a different AC compressor and bracket if there is one that can be used better or easier with the 67 then the one I currently have. I'm having some problems fitting the AC compressor bracket to the block with my motor mount plates as they stick out further forward, I was thinking about clearencing the bracket but I don't want to structurally compromise the bracket, what are your guys thoughts? I suppose there is the high mount AC option as well, but I do like how the compressor is tucked in out of the way with the low mount.

The low mount is nice until you have to work on it! My opinion only. I like the look of the higher bracket it gives it the old school look that people all are looking for even with the fuel injection and yours being carb would look right at home. I used
http://www.classicautoair.com/Chevy_..._Chevy_AC.html
I used their kit at the bottom of the page. When I did the LS swap I had to buy a new bracket. LS1 bracket.

[Hart_Rod]

Originally Posted by TR65

MB,

Check out my thread. Should be similar to what you have.

http://67-72chevytrucks.com/vboard/s...d.php?t=468107

I use the stock pressure sensor and the ECM to control the fans according to the high side pressure, so either none, one, or two fans come on as needed.

TR

So your sensor controls the fans, but doesn't cause the compressor to turn on or off?

Originally Posted by TR65

At least on my 2005 LS2 (E40 ECM) the ECM is quite happy to control the AC system pressure with the fans even though it does not have an AC request. As LS1nova pointed out, I would have to get the AC request onto the serial bus somehow. The only issue is that the ECM can't cut the compressor off in case of a pressure fault.

TR

Can you explain what you mean by a pressure fault? TIA

[foamypirate]

Originally Posted by Hart_Rod

So your sensor controls the fans, but doesn't cause the compressor to turn on or off?



Can you explain what you mean by a pressure fault? TIA

I know I'm not TR65, but it sounds like my A/C setup (wiring/PCM wise) is pretty much the same as his. I have a factory 05' (Sierra Denali) pressure transducer in my compressor discharge line. Like TR65 mentioned, it controls only the fans, since you need a serial request for the computer to control the compressor. The PCM will still see the pressure in the system and run the fans without the A/C request signal.

As far as the pressure fault goes, there is a high/low pressure protection system built into the PCM. If the A/C pressure goes too high or too low (low is normal, just cycling the compressor on/off to prevent freezing the evap), the PCM will turn off the compressor. It will also cut off the compressor with WOT. Since we lose PCM control of this, you would need a low pressure and high pressure switch in the system, wired in series, to cut off the compressor in these situations. In my case, I used the factory low pressure switch (88' squarebody crewcab), and my replacement Denso 10S17F had a high pressure switch in the back of the compressor body (which cuts out at 455psi). So, I have 12v from the factory control head, through the low pressure switch, through the high pressure switch, to my relay, which controls the 12v+ side for the compressor. If any of the switches goes open, my compressor shuts off.

[Hart_Rod]

Originally Posted by foamypirate

I know I'm not TR65, but it sounds like my A/C setup (wiring/PCM wise) is pretty much the same as his. I have a factory 05' (Sierra Denali) pressure transducer in my compressor discharge line. Like TR65 mentioned, it controls only the fans, since you need a serial request for the computer to control the compressor. The PCM will still see the pressure in the system and run the fans without the A/C request signal.

As far as the pressure fault goes, there is a high/low pressure protection system built into the PCM. If the A/C pressure goes too high or too low (low is normal, just cycling the compressor on/off to prevent freezing the evap), the PCM will turn off the compressor. It will also cut off the compressor with WOT. Since we lose PCM control of this, you would need a low pressure and high pressure switch in the system, wired in series, to cut off the compressor in these situations. In my case, I used the factory low pressure switch (88' squarebody crewcab), and my replacement Denso 10S17F had a high pressure switch in the back of the compressor body (which cuts out at 455psi). So, I have 12v from the factory control head, through the low pressure switch, through the high pressure switch, to my relay, which controls the 12v+ side for the compressor. If any of the switches goes open, my compressor shuts off.

Thanks for the info. Does your compressor come on and stay on until you turn it off? Mine isn't it's cycling on and off and I assume it is being controlled by the computer, which would lead me to believe that it has some over/under pressure protection that is being provided by the PCM. But I would like to be certain because I don't want to damage anything. Thanks again. FYI, I'm using a 2006 Tahoe P59 PCM. More info here: http://67-72chevytrucks.com/vboard/s...=709611&page=2

[foamypirate]

Originally Posted by Hart_Rod

Thanks for the info. Does your compressor come on and stay on until you turn it off? Mine isn't it's cycling on and off and I assume it is being controlled by the computer, which would lead me to believe that it has some over/under pressure protection that is being provided by the PCM. But I would like to be certain because I don't want to damage anything. Thanks again. FYI, I'm using a 2006 Tahoe P59 PCM. More info here: http://67-72chevytrucks.com/vboard/s...=709611&page=2

Yeah, mine will cycle due to to the low pressure switch being in series with the signal to the A/C clutch relay. When the pressure gets too low, it goes open to cut off the compressor, and prevent the evaporator from freezing up.

To confirm how yours is controlled, you'd need to trace the wiring. If the trigger wire to the relay is coming from the PCM, the PCM is controlling the cycling. For a 2006 PCM to do so, I believe it would need to have a serial A/C request in most cases. I have heard of a few cases where people were able to get the later PCM to accept a 12v+ A/C request, but in talking to a few tuners and harness builders, it was hit or miss on success.

If the trigger wire is coming from the low pressure switch on the accumulator (assuming you have one, and aren't using a POA valve system), the cycling will likely be controlled by that switch.

[Hart_Rod]

Originally Posted by foamypirate

Yeah, mine will cycle due to to the low pressure switch being in series with the signal to the A/C clutch relay. When the pressure gets too low, it goes open to cut off the compressor, and prevent the evaporator from freezing up.

To confirm how yours is controlled, you'd need to trace the wiring. If the trigger wire to the relay is coming from the PCM, the PCM is controlling the cycling. For a 2006 PCM to do so, I believe it would need to have a serial A/C request in most cases. I have heard of a few cases where people were able to get the later PCM to accept a 12v+ A/C request, but in talking to a few tuners and harness builders, it was hit or miss on success.

If the trigger wire is coming from the low pressure switch on the accumulator (assuming you have one, and aren't using a POA valve system), the cycling will likely be controlled by that switch.

Here's how my system is setup:

My setup:
3 wire truck pressure transducer connected to plug from Speartech harness
12volt a/c signal from the VintageAir to Speartech harness green a/c request wire
Two wire (green and black) plug to factory 2005 compressor from Speartech harness
NO binary switch (in dryer not wired)
Blue/Green PCM OS 12587811 & system 12591524
Compressor type - ANALOG

[foamypirate]

Originally Posted by Hart_Rod

Here's how my system is setup:

My setup:
3 wire truck pressure transducer connected to plug from Speartech harness
12volt a/c signal from the VintageAir to Speartech harness green a/c request wire
Two wire (green and black) plug to factory 2005 compressor from Speartech harness
NO binary switch (in dryer not wired)
Blue/Green PCM OS 12587811 & system 12591524
Compressor type - ANALOG

Definitely sounds like the PCM is controlling it, in that case. That's really the best way to do it, as you'll have WOT compressor cut off, high pressure cut off, etc.

[Smokinjoe00]

Originally Posted by 87chevy.com

interesting.. I used the factory 5.3 a/c compressor and mount, and didnt have to space anything out. My compressor has a different manifold, a 2 seperate hose set. none the less the a/c works awesome... easily hits 50* out the vents . I charged my system to 2.25lbs.
clint

can you take a few pictures and tell me where you got your hoses built or part numbers?
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