Announcement

Collapse
No announcement yet.

Running 4 port MAC valve 'backwards'

Collapse
X
Collapse
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Running 4 port MAC valve 'backwards'

    Bit of a random one. But i bought a 4 way mac valve for the MX5 and intended to use it with AN fittings. However, one of the ports is tapped on a slight angle, which means that the A and B ports have a clash when trying to do up the AN fittings:



    Same AN fittings work on the other side with some clearance


    However, this would mean the 'flow' is backwards compared to intended. What i am wondering is if the passages in a MAC valve are bidirectional or are they unidirectional? The diagram suggests some form of directionality, but is that just in the diagram or is it in the valving? Can i set it up plumbed the other way around, with A and B functioning as EX and IN respectively, and vice versa?

    That would make it easier for plumbing in the engine bay as well.
    Last edited by takai; 23-06-20, 10:23 AM.
    Chris
    ------
    The new nugget
    I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself. - D.H.Lawrence

    #2
    To fix your original issue - send the part back to supplier and get a mac valve with correctly angled threads sent out. Cant help with the port assignment as i dont have one in front of me to test.

    Comment


      #3
      If you connect it "backwards" you might lift the valve from the seat depending on the pressure. I have seen that happen with OEM type 3 port solenoids when trying to use them backwards.

      Comment


        #4
        What Marshy said would be best. Or you could put a 90 degree fitting in one of the ports to gain some clearance.
        Originally posted by Marlin
        Chickens will slip under water in the cover of darkness like a seal team and FUCK YOU UP.

        Comment


          #5
          Would be fine, a 4/2 valve never has a blocked port like an odd numbered valve does 3/1, 5/2. These types don't work backwards as there must be a balanced port for the blocked pressure to not push it open (or solenoid force when in active position exceeds this pressure). A 4/2 always has both paths open so no dP is present over a blocked port.
          Last edited by burn is weird; 24-06-20, 06:33 PM.

          Oo___oO

          Comment


            #6
            Fit and tighten AN hose fiting onto adapter fitting (so that it will never, ever come off) then grind the flats off the hose fitting so that you can screw the adapter thread in and tighten with tools and the hose fitting has nothing left to foul
            Originally posted by Keith Duckworth
            "I think that in a racing engine, the closer it is to disintegrating, in general the better its performance will be "

            Comment


              #7
              Originally posted by doctor ed View Post
              Fit and tighten AN hose fiting onto adapter fitting (so that it will never, ever come off) then grind the flats off the hose fitting so that you can screw the adapter thread in and tighten with tools and the hose fitting has nothing left to foul
              Yeah. Have thought about just grinding down one point on the adapter too, that way there are still the rest of the flats and points to grip onto if it ever needs to be changed.
              Chris
              ------
              The new nugget
              I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself. - D.H.Lawrence

              Comment


                #8
                Just note, A and B are not ports, they are positions and could cause confusion. What you want to do will work, the valve will still switch, but the positions will be reversed on the diagram.

                A - Air flows continuously from 2 to exhaust. Inlet is vented to 1.
                B - Air flows continuously from 2 to inlet. Exhaust is vented 1.

                Originally posted by burn is weird View Post
                Would be fine, a 4/2 valve never has a blocked port like an odd numbered valve does 3/1, 5/2. These types don't work backwards as there must be a balanced port for the blocked pressure to not push it open (or solenoid force when in active position exceeds this pressure). A 4/2 always has both paths open so no dP is present over a blocked port.
                It's worth checking what is connected to the valve though as A and B aren't ports, they are positions in case of any confusion from the OP. The ports are 2 and 1, if you treat them as A and B it's backwards. The second photo shows the valve plumbed correctly with the inlet to port 2 though, but just checking to make sure that wasn't just copied from the other side or you might cause a clusterfuck reading a schematic for another component you want to add to the circuit.
                Last edited by Madhatr; 29-07-20, 10:38 AM.
                Originally posted by Buford T. Justice
                This happens every time one of these floozies starts poontangin' around with those show folk fags.

                Comment

                Working...
                X