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Anyone made their own 4 port manometers ?

Discussion in 'XJ Technical Chat' started by Knick, May 24, 2006.

  1. Knick

    Knick Member

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    Two ports are easy (just a piece of tubing with fluid)

    I was thinking of doing a 4 ports, sort of like this.

    (need to do a drawing.. but here goes)

    Four tubes (clear pvc tubing), from carbs up to the top of a 6-8 ft plank.

    Then down the plank, under and up the back a little ways (say 1-2ft).

    They all connect to a common tank of fluid.

    This way I can tweak the mixture on all four carbs at once.
    Then I can sync.

    I say mixture first to get the best lean/rich mix. Then sync the vacum of those.

    Question # 1 The "manual" assumes a good mixture setting before you sync so I assume this is ok ?

    Q # 2 Anyone else used a water manometer or anything like what i discribed ?

    Should be the same functionally as a Mercury one, but more sensitive due to lighter weight of water.. you could switch water for oil/ATF etc if over sensitive.

    Thoughts ?

    or am i crazy 8O
     
    Knick, May 24, 2006
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  2. Hired_Goon

    Hired_Goon Member

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    Hired_Goon, May 24, 2006
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  3. Knick

    Knick Member

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    To make sure i understand your setup, it's four tubes, partially filled, connected togather (by Y connectors or manifold type setup ?)

    No open connections, all open connections are on the vacuum ports on the carbs ...



    My goal was to not only measure compared vacuum (balance), but also absolute vacuum (how well each carb is pulling).

    Of course this is based on using vacuum and tach to tune automotive carbs..

    I dont want to Gimp one cylinder just to match the others..
     
    Knick, May 25, 2006
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  4. Hired_Goon

    Hired_Goon Member

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    Not sure what you mean by gimp one to match the others, but essentially that's exactly what you are doing.

    To get an XJ running right you are essentially making all four carbs draw the same amount of air(vacuum) so that each cylinder gets exactly the same air/fuel mix.

    Absolute vacuum(not really relevant IMO) can be measured on each cylinder individually with a single vacuum guage.


    You could use a pair of y connectors but I used a four way one for simplicity. No open connections.
     
    Hired_Goon, May 25, 2006
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