Stock air conditioning with LS swap
 

Is anyone here using the factory ac their truck came with? I am to the point where I need to start making plans for the ac and where to put this trinary switch that the pcm uses to control the fans and ac compressor..

Any help or pictures would be much appreciated.

Re: Stock air conditioning with LS swap
 

Read Glock's build.

Specifically around post #656 & 1309

Re: Stock air conditioning with LS swap
 

Already read through his build, the ac on his 85 is a bit different than the 68, which I forgot to mention.

Re: Stock air conditioning with LS swap
 

Are you dead set on keeping the Expansion valve/ POA valve/ Receiver Dryer system? It would be cheaper & easier to replace the Evaporator core with a fixed orifice style evaporator (Ive found 77 Olds 98 evaporators fit the best) & run a Accumulator & Orifice tube.

What year/make/model did your LS come out of? GM put the high side trinary in different places, sometimes in the discharge side, sometimes in the liquid line.

Re: Stock air conditioning with LS swap
 

I am open to suggestions on what is going work the best and for the least amount of $$. That is why I was going to keep the original equipment. Do you have any pics of a 68 with this type of system installed?


The engine is from a 2007 Trailblazer SS LS2. The ac compressor is a Denso 10S17F from a 2005 Silverado 5.3.

Thanks, Greg

Re: Stock air conditioning with LS swap
 

Short-T,

I am in the process of installing a vintageair evaporator in my 65 but I am trying to use the ECM to control the fans and the AC clutch like you are. I have a 2005 LS2 from an SSR (E40 ECM).

What it uses is a pressure transducer that the ECM uses to protect the compressor in case of over or under pressure. Then it uses the pressure values to determine when no fan, 1 fan, or 2 fans need to run. There are tables in the ECM that you can modify if you want.

So I bought the pressure transducer from GM and an adapter from Doc's Blocks and I am going to aluminum braze it in the compressor discharge line. I am using the stock LS2 Sanden scroll compressor that came with the engine.

That is the last part of my AC install so not quite finished.

TR

Re: Stock air conditioning with LS swap
 

That should work, the switch you are talking about is a trinary switch. Gives the ok to the ecm for the compressor to come on and controls the sencond fan when pressures get to high within the system.

I've been trying to find this adaptor for my stock GM trinary switch, would you mind sharing the pn for it? Thanks, Greg

Re: Stock air conditioning with LS swap
 

Short-T,

Here is the part:

http://www.docsblocks.com/products.asp?cat=20

Product ID: AC0146
Round Stock, Aluminum Refrigerant Valve 134A-standard flow Details

M10 x 1.25 Thrd switch port, .280 base
Price: $1.57

And you need a R134 schrader valve and -6 o-ring.

Here is a Pic of the whole rig including pressure transducer.

TR

Re: Stock air conditioning with LS swap
 

Thanks TR! I look all over Docs Blocks and didn't see that...

I went through your build and love the work you have done. Must be a pleasure to drive and show off at the show's. How do you like the way the LS2 performs?

Greg

Re: Stock air conditioning with LS swap
 

Short-T,

Yea, I looked thru Doc's several times, and ordered the wrong one once before I found it. Then it is $1.57. I paid more than that for WhopperJr for lunch today.

Thanks for the kind words. The LS2 is better than I imagined it would be. Starts every time, idles perfect in all conditions, completely docile until you open it up, then hold on. It has been dead reliable since I started it last July. Loves to cruise at 75. Daily driver.

TR

Re: Stock air conditioning with LS swap
 

I wired the a/c up without that switch... only things i have in the circuit is the low psi switch and the compressor clutch, and a/c relay... operates like it should from facotry with the ecm controlling the a/c relay.
clint

Re: Stock air conditioning with LS swap
 

Short-T,

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

TR

Re: Stock air conditioning with LS swap
 

TR, looking good! Are you using the ac compressor that came with your engine? If so I'd like to know how you mounted it to the engine after replacing your oil pan?

Keep up the great work!
Greg

Re: Stock air conditioning with LS swap
 

Thanks Greg,

Yep, I am using the OE compressor. The mounting was a real ordeal, so bad I don't even have any good pictures. So as you know, the truck oil pan doesn't have the two lower compressor mounting holes. I spaced out the compressor with 5/16" spacers on the top block mounting holes. That gave me room to bolt a 5/16" aluminum plate to existing block mounting holes and provide holes for the lower compressor mounting bolts, I put nuts on them. It also took some clearance machining on the compressor mounting cradle and the compressor itself. Moreover, I need that 5/16" for frame clearance. I also had to cut a access hole in the crossmember to reach the lower rear compressor mounting bolt. So far I have not had to cut the frame for clearance, that is my goal.

I am determined to use the low mount compressor. So, I hope all the above works.

The pic below shows some of it.

TR

Re: Stock air conditioning with LS swap
 

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

Re: Stock air conditioning with LS swap
 

Good idea! I wish I had seen this before going out and getting a truck compressor and bracket. I would have like to use the compressor that came with the front sump oil pan because the ports are clocked higher than the truck ones. Do you know anyone that needs a ac compressor and bracket? LOL!

Nice job on the switch fitting, I ordered mine last week so its hurry up and wait!

Greg

Re: Stock air conditioning with LS swap
 

Thanks for the info guy's. I have a 01 harness and pcm. What pins do I need to add to the pcm to add electric fans? I want the fans to turn on with the a/c
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Re: Stock air conditioning with LS swap
 

That's how I did mine as well. I used the stock 5.3L compressor with the Old Air system and it looks and works great. Old Air is nice because you can buy a kit that doesn't include the compressor, condenser, or hoses and save some $$$.

Re: Stock air conditioning with LS swap
 

Do you guys run electric fans? If so do you have them turn on when you run the AC?

You can also just buy the evaporator unit from Vintageair. That is what I did.

By the way. It is not a switch. It reads the high side pressure. Then in the tune you have tables that allow you to turn one fan on and off at one set of pressures and a second fan on and off at another set of pressures. Keeps the fan use to a minimum. Of course the system would run fine without that.

TR

Re: Stock air conditioning with LS swap
 

I use a "differential type" trinary to trigger the fan relay "on" at 250psi & "off" at 200psi of head pressure.

I have a question....How are you guys sending a A/C request to the PCM without the factory control head? Or does the factory "pressure transducer" signal turn the fans on/off based on pressure, speed etc., without a A/C request?

Re: Stock air conditioning with LS swap
 

To send an A/C request to the PCM, you just take the wire that originally went to the compressor clutch, and wire it to the A/C request wire going to the PCM. The catch is, you can only do it on the 2002 and older systems, as the 2003 and up the request is sent via serial data. There has been some talk about being able to change certain files in the tune with Tunercat to be able to use the newer PCM with the older style 12v A/C request, but I haven't looked into it much.

Re: Stock air conditioning with LS swap
 

I am using 2 12" Spal fans on the radiator (I don't have a fan on the condenser). The AC ON switch turns on the compressor (through a binary switch) and also actives a relay that turns both fans on. It seems to work pretty well.

John from Speartech told me that the newer motors (mine is 2008) with the serial AC request will automatically adjust the RPM for the added load. He appears to be right since that is exactly what mine does when I turn on the compressor.

Re: Stock air conditioning with LS swap
 

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

Re: Stock air conditioning with LS swap
 

good information, I am trying to install the AC on my truck (is a ford 76), I just bought some fittings and parts to install the AC. I install a 4.8 Vortec from a 04 GMC, but the compressor is form a 2000 Chevy truck. I am keeping the Receiver/Expansion Valve/Evaporator system, can I run it without the trinary switch, I have electric fans on my engine, and the computer turn them on/off. Thanks for your help

Re: Stock air conditioning with LS swap
 

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.

Re: Stock air conditioning with LS swap
 

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.

Re: Stock air conditioning with LS swap
 

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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Re: Stock air conditioning with LS swap
 

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.

Re: Stock air conditioning with LS swap
 

Then refill compressor with what type of oil
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Re: Stock air conditioning with LS swap
 

Mineral Oil http://www.oreillyauto.com/site/c/de...2726&ppt=C0050

Re: Stock air conditioning with LS swap
 

Thanks looks like enough to put some in and re drain. How much should that compressor hold.
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Re: Stock air conditioning with LS swap
 

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.

Re: Stock air conditioning with LS swap
 

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

Re: Stock air conditioning with LS swap
 

[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.

Re: Stock air conditioning with LS swap
 

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



http://67-72chevytrucks.com/gallery/...m/IMG_3602.JPG

Re: Stock air conditioning with LS swap
 

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

Re: Stock air conditioning with LS swap
 

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

Re: Stock air conditioning with LS swap
 

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.

Re: Stock air conditioning with LS swap
 

Ttt

Re: Stock air conditioning with LS swap
 

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.;)