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The Detailed E30 R-134a Conversion Thread/DIY

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    A couple question for those who have done the "full monty" conversion.

    1. If I am replacing the expansion valve, how much extra work/hassle is it to replace the evaporator core "while I'm in there?"

    2. Where is the evaporator temperature sensor located? What does it do? I don't see it mentioned in conversion threads.

    Thanks, Cory
    1992 325i 'vert
    1988 320i Touring
    1977 530i
    2015 328i - Euro Delivery/Performance Center Delivery
    2001 325i - R.I.P.
    BMWCCA
    E30CCA

    Comment


      Originally posted by cory58 View Post
      A couple question for those who have done the "full monty" conversion.

      1. If I am replacing the expansion valve, how much extra work/hassle is it to replace the evaporator core "while I'm in there?"

      2. Where is the evaporator temperature sensor located? What does it do? I don't see it mentioned in conversion threads.

      Thanks, Cory
      1. Very little since you've already removed the glove box, disconnected the hoses etc. u less you think it leaks or is badly gunned up, you may want to just flush it.

      2. Just above the gas pedal. It's there to deactivate the compressor if the evaporator temp drops below 38. If you replace the evaporator DO NOT use the sensor to pierce the new fins. It is too soft and can deflect which, in my case it did, and blocked the blend door.
      Deck Lid and soft top Shocks on hand

      Seat shocks on hand for immediate shipment
      https://www.r3vlimited.com/board/sho...86#post4944786
      Alice the Time Capsule
      http://www.r3vlimited.com/board/showthread.php?t=360504
      87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

      Comment


        Originally posted by jeffnhiscars View Post
        2. Just above the gas pedal. It's there to deactivate the compressor if the evaporator temp drops below 38. If you replace the evaporator DO NOT use the sensor to pierce the new fins. It is too soft and can deflect which, in my case it did, and blocked the blend door.

        Thank you Jeff! Sorry to be a newb, but what do you mean by "pierce the new fins" on a replacement evaporator?


        Cory
        1992 325i 'vert
        1988 320i Touring
        1977 530i
        2015 328i - Euro Delivery/Performance Center Delivery
        2001 325i - R.I.P.
        BMWCCA
        E30CCA

        Comment


          Originally posted by cory58 View Post
          Thank you Jeff! Sorry to be a newb, but what do you mean by "pierce the new fins" on a replacement evaporator?


          Cory
          The evaporator has soft aluminum fins and while there is a guide hole on the heavier steel end plate, the fins themselves do not have holes for the sensor. Its easy to drive something through the fins but the sensor itself is not rigid enough for this task and WILL deflect.

          Hence, use a thin screw driver or awl (something with a semblance of a point) o create a straight bore for the sensor. It doesn't have to be a precise fit as the sensor is measuring air temp.
          Deck Lid and soft top Shocks on hand

          Seat shocks on hand for immediate shipment
          https://www.r3vlimited.com/board/sho...86#post4944786
          Alice the Time Capsule
          http://www.r3vlimited.com/board/showthread.php?t=360504
          87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

          Comment


            Originally posted by parkerbink View Post
            It's hard to see but the compressor seems to have a wobble. Do I need to contact the seller?

            Because it's a video it won't let me do anything but post the link. Sorry

            https://www.flickr.com/photos/946846...posted-public/
            Hi there. I was looking at your video and trying to figure out the parts needed to mount this on the M20 engine.

            I believe the black brackets on the screenshot attached are needed and I can probably fabricate these myself. But I was wondering if this is mounted to the OEM bracket that attaches to the engine block listed here: https://www.ecstuning.com/b-genuine-...t/64521717007/

            Any chance you can confirm that is what you are using with the SD508 or post a picture of what you have? EDIT: Actually, this looks like the Sanden bracket on this post: https://www.r3vlimited.com/board/sho...d.php?t=358611 that is not easy to find.

            Thanks.
            Attached Files
            Last edited by bellerto; 07-18-2018, 05:15 PM.
            Youtube Channel
            '89 325i Convertible
            '19 VW Atlas
            '19 Subaru STI

            Comment


              Originally posted by jeffnhiscars View Post
              I bought a roll of 2" insulating foam tape from an AC supply house.
              Does that help with moisture as well? I am getting water running down the pass side of my heater box with the AC on. I need to pull the glove box & find the source, but I suspect it is the expansion valve or lines.

              Comment


                Originally posted by Caperix View Post
                Does that help with moisture as well? I am getting water running down the pass side of my heater box with the AC on. I need to pull the glove box & find the source, but I suspect it is the expansion valve or lines.
                That could be a cause but don't rule out a clogged drain
                Deck Lid and soft top Shocks on hand

                Seat shocks on hand for immediate shipment
                https://www.r3vlimited.com/board/sho...86#post4944786
                Alice the Time Capsule
                http://www.r3vlimited.com/board/showthread.php?t=360504
                87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

                Comment


                  Originally posted by jeffnhiscars View Post
                  That could be a cause but don't rule out a clogged drain
                  I blew air through both drains from the bottom, the pass side is pita to get at. Both drains do have water draining out of them, when I pulled back the corner of the center console it looked to be running down the side of the box from further up.
                  I do not know how long the a/c did not work in this car, I feel like it was probably a large number of years. I did not see anything obvious when I replaced the expansion valve, but the insulation was falling apart.
                  One other question on converting to r134a, is it normal for them to have poor performance at idle? I have replaced every part but the evaporator & have a spal 16" pusher installed. With some rpm it works great, but at idle in 90 degree heat with 90% humidity its a little warm. I need to hook some gauges to it and see what my pressures look like. I filled with 2 lbs but I don't know if the parallel flow condenser increases capacity.

                  Comment


                    Originally posted by Caperix View Post
                    I blew air through both drains from the bottom, the pass side is pita to get at.

                    One other question on converting to r134a, is it normal for them to have poor performance at idle?
                    A few thoughts. My HVAC box has three drains. One on each side then one in the middle near the ash tray.

                    For the leaking near the expansion valve, find some insulated tape, when that area is dry, and seal it all up.

                    Iíve rebuild my system and at idle the performance is poor. With my 325E and the low gear Iíve started staying in a gear lower than normal to keep the RPMs up.
                    2004 525i Manual - 1985 325E Coupe Manual

                    Comment


                      Originally posted by tomstin View Post
                      A few thoughts. My HVAC box has three drains. One on each side then one in the middle near the ash tray.

                      For the leaking near the expansion valve, find some insulated tape, when that area is dry, and seal it all up.

                      Iíve rebuild my system and at idle the performance is poor. With my 325E and the low gear Iíve started staying in a gear lower than normal to keep the RPMs up.
                      I'll have to look into that 3rd drain & pick up some insulation tape. I guess the poor idle performance is just one more reason to look into a 24 valve swap.

                      Comment


                        A couple more notes.

                        The insulated tape isn't to seal but rather is to limit condensation at the expansion valve and connections.

                        Any AC will under perform at idle given the lack of air flow to help dissipate heat. My understanding of a swap is you delete the mechanical fan which would actually have a negative effect on air flow at idle.

                        There is no magic bullet. Clean tight system, evac to 500 microns, charge and go.
                        Deck Lid and soft top Shocks on hand

                        Seat shocks on hand for immediate shipment
                        https://www.r3vlimited.com/board/sho...86#post4944786
                        Alice the Time Capsule
                        http://www.r3vlimited.com/board/showthread.php?t=360504
                        87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

                        Comment


                          Originally posted by tomstin View Post
                          A few thoughts. My HVAC box has three drains. One on each side then one in the middle near the ash tray.



                          For the leaking near the expansion valve, find some insulated tape, when that area is dry, and seal it all up.



                          Iíve rebuild my system and at idle the performance is poor. With my 325E and the low gear Iíve started staying in a gear lower than normal to keep the RPMs up.


                          I have a similar issue, all a/c components have been replaced with new r134a except the evaporator and the a/c compressor, all seals in the system have been updated with r134a seals including the a/c compressor, but my idle a/c performance is poor.... weak compressor? Any ideas? Thanks


                          Sent from my iPhone using Tapatalk

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                            Did we ever figure out if other compressors would bolt on with little or no modification? My compressor crapped out so I need to get a new one. Im not adventurous enough to go all electric. If not Ill probably go on a hunt in the junk yard and see what I can find.

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                              What is the material around the expansion valve? mine is no longer reusable!

                              Comment


                                Originally posted by changyeamoon View Post
                                What is the material around the expansion valve? mine is no longer reusable!
                                Any AC supply house will sell you a small roll of insulating tape. The original stuff appears to be a combination of butyl and some kind of foam bead. Either way it's just an insulator to limit condensation at the expansion valve.
                                Deck Lid and soft top Shocks on hand

                                Seat shocks on hand for immediate shipment
                                https://www.r3vlimited.com/board/sho...86#post4944786
                                Alice the Time Capsule
                                http://www.r3vlimited.com/board/showthread.php?t=360504
                                87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

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