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Finally got the A/C working(PIC'S)

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by BobK, Jul 19, 2004.

  1. BobK

    BobK 1/2 ton status

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    Finally got the A/C working(PIC\'S)

    Well I had rebuilt my A/C and heating system about 5 months ago but never got around to getting the A/C working.

    I got er done last week though.

    I retro'd the system from R12 to R134a and got rid of the POA valve.
    I used a POA eliminator from Old Air Products.Along with a fixed orafice tube(FOT) and a pressure cutout switch.

    The system cools O.K.,still some fine tuneing needed but I get about 50F at the vents.Not bad but I'd like it colder.

    Here's a few pic's of the process.

    This is the connection to the low pressure side of the system.That's the POA eliminator I had mentioned earlier.An integral pressure cutout switch comes with the POA eliminator.
    I just spliced into the existing A/C compressor wire.What it does is it shuts down the compressor and prevents the evap. from feezeing up.
    [​IMG]

    Here is the high side connection at the compressor.I used a Sanden SD5H14 compressor.
    [​IMG]

    I used is a RobinAir,1/2hp,6cfm vacume pump to evacuate the system before charging.
    [​IMG]

    The gauge set I used.This allows you to measure the vacume you pull on the system as well as the pressure in the system while chargeing it.
    In this pic I'm evacuating the system.The gauges are at -29.5inHg,which is as far as you can go on the planet Earth.
    [​IMG]

    The can tap I used.I ended up overcharging the system a bit.I used four(4),12oz cans of R134a to charge it up.
    [​IMG]

    Killin time while evacuateing the system
    [​IMG]

    I connected my can tap to my vacume pump via an adaptor I bought at Car Quest.This way I can eliminate the chance of air getting in the system when I have to change cans during the charging process.
    [​IMG]

    I had to "jump" the cutout switch during the first bit of charging.The compressor would not engage untill some pressure was in the system.
    [​IMG]

    Just an overhead view of things.
    [​IMG]

    This is the top tube of the evaporator core.Condensing like it should,cool to the touch but not iceing up.
    [​IMG]

    And the bottom line.The line on the right is the FOT.It meters the amount of r134a that got through the evap. core.It function like the TVX valve on the old POA system.
    [​IMG]

    Like I said I still nedd to "tune" it a bit.Might need to put in a smaller FOT or take out a bit of R134a.Worst case would be a new parallel flow condensor.I have the orig. type in there now.Through the reading I've done the orig. condensor design may not work that well when retro'd to R134a.
     
  2. clubba68

    clubba68 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    Nice Bob. Very detailed. Good work. /forums/images/graemlins/waytogo.gif
    Hey, what engine do you have in that guy?
     
  3. BobK

    BobK 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    Mildly built SBC350 with a 92 speed density TPI from a Iroc Camaro.
     
  4. clubba68

    clubba68 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    [ QUOTE ]
    Mildly built SBC350 with a 92 speed density TPI from a Iroc Camaro.

    [/ QUOTE ]
    /forums/images/graemlins/thumb.gif
    I was mainly interested in the TPI setup. I know you hear it all the time, but you've got a sweet ride there Bob. /forums/images/graemlins/bow.gif
     
  5. BobK

    BobK 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    Well...I hear it...not all the time...but it's always nice to hear it.
    Thanks!
     
  6. BobK

    BobK 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    Well...good news
    Today I added 6oz. of R134a for a total of 36oz in the system.Had some good results with this change.

    Here's the data as of today(7/22/04)

    At about 1700rpm
    low=25
    high=peaked at 260
    vent temp-44-46F
    ambiant temp lower today=75F.
    fan on high
    Compressor cycled,on for 30sec,off for 5sec.

    at Idle(approx.700rpm)
    low=30-38
    high=180-230
    vent temp=44-46F.
    fan on high
    Compressor DID NOT cycle.

    Here's the kicker.
    I turned the interior fan on low and my vent temps dropped even more.

    at idle
    low=30
    high=180
    vent temp=38-40F.!!!!
    Compressor DID NOT cycle.

    At 1700 rpm
    low=25
    high=200-220
    vent temp=42-43F.
    Compressor cycled,on 30 sec,off 5sec.

    So I'm pretty happy with those vent temps.

    Thanks to those that made suggestions.

    Hope this info. can help others down the line.
     
  7. Yukon Jack

    Yukon Jack 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    Better grab a coat, brrr /forums/images/graemlins/histerical.gif
     
  8. BobK

    BobK 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    Ya baby...brrrr /forums/images/graemlins/peace.gif
     
  9. 1972jimmy

    1972jimmy Registered Member

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    Re: Finally got the A/C working(PIC\'S)

    Bob,

    Thanks for the info. Do you have the mfgr part numbers that you used to rebuild the AC system?

    On another note.....I have a blower airflow problem in my 72 Jimmy and replacing the blower motor did not fix the problem. The blower motor is working fine but the airflow from the vents is extremely poor and the airflow volume between low and high blower speeds is practically the same.

    My question is...is there something I should check before I have to pull the fender and check for the proverbial bird's nest in the firewall unit?

    Thanks,
    Mark
     
  10. BobK

    BobK 1/2 ton status

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    Re: Finally got the A/C working(PIC\'S)

    [ QUOTE ]
    The fan speed's are the same

    [/ QUOTE ]
    Do you at least hear a change in the rpm of the fan when switched to high?

    If the high speed fan relay was bad the fan would stop when switched to the high position.

    My bet is the ducting is clogged with something,nest,dead animal,bee hive,etc.

    Take it apart.It's a bit of a pain but worth it.

    Mine was pretty clean when I took mine apart but it does flow better now.

    As far as part numbers go,everything is stock replacement except for the compressor.
    So parts can be had just about anyplace that sells our 1st gen parts.

    Oh ya,I did have to have the hoses made by a local A/C shop and I did modify the evap. core to accept the Fixed Orafice Tube but that only cost me $20 for a local shop to TIG an aluminium fitting onto the evap. core.

    I got all my A/C part through
    www.rickspickupparts.com
    Ask for Shawn.He's a good guy and will help you out,no problem /forums/images/graemlins/smile.gif
    I paid:
    -POA eliminator=$85
    -Orifice tube and housing=$35
    -condensor=$150
    -receiver/dryer=$40
    -aluminium hard lines=$30
    -Sanden compressor=$210
    -compressor mounting brackets(Alan Grove)=$85
    -shipping=$24.24
    -----------------------------------------------
    Total=$659.24

    My conversion cost this much as all I had to start with was the evap. core.Everything else had been removed by the previous owner. /forums/images/graemlins/thumb.gif
     

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