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calibrate analogue vacuum gauges

Discussion in 'Technical and Troubleshooting Torque' started by aviper4u, Mar 27, 2007.

  1. Hi

    I bought the following vacuum gauge bank from MCAS;


    so my question is how do i calibrate to make sure they read the same on the gauge for the same vacuum.

    im thinking hook all of em up to the same carburettor, one at a time and adjust but what i'm unsure of, is how to physically adjust any errors in the gauges themselves.

  2. You can have it calibrated, but it is new and should not need it. One thing you could do is hok them all up to one vacuum source with some tees, and see how they read.
    Just use the thing I say. It should not need calibrating.

    Regards, Andrew.
  3. have used it once before and out of the box the dials were the same but after initial use the dials are now different from each other.

    hence my calibrating advice questions.

    i noticed a screw in the gauge anyone know how the adjustment procedure works?
  4. Ths screw is probably a damper.
    As I said, connect them ALL to the same vacuum source AT THE SAME TIME.
    Gauges often come to rest owhere near zero, it is internal friction in teh mechanisms, what is important is they are accurate in their working range.
    Frankly, calibration is going to cost you more than the $120 to replace them.

    Regards, Andrew.
  5. yea found out how to adjust i need to remove the clear covers and turn the screw which moves the dial up or down.

    thanks for assistance
  6. What brand are they? I want to make sure I don't buy them!

    Regards, Andrew.
  7. they are emgo brand i believe bought through MCAS in sydney i dont believe they are as accurate as mercury gauges but didnt want the risk and hassle associated with mercury guages.
  8. Do a search on teh net for instructions on how to make your own manometer, costs around $20 and deadly accurate.

    Regards, Andrew.
  9. I have the same set.

    Firstly I do as has been previously suggested and check each dial on a single vacuum source, I even place a mark on the glass with a black marker (the glass is easy to turn and move your mark).
    Once I am confident I can get a similar reading of all gauges (in reference to the black mark), I do the synchronization.
    After doing the synch, then to double check, I will throw the same single gauge on each carb or throttle body and check each reads the same.

  10. Being the type of person that likes to tinker and build my own equipment i tried to give this a go today but i have minor problem.

    I have made the adapter for the carby using a 4mm socket head bolt and i drilled it out about 2 mm but the water in the hose was jumping around too much so i made another drilling the hole 1mm which made a difference but its still jumping around so my question is does the original part No 09913-13140 adaptor have a smaller hole or is there something else i have done wrong.
    I tried to do a search on the part for some specs but i didn't have any luck so i thought someone with the part could have a look and see if the hole is a tiny pin hole smaller than 1mm.

    The water is jumping up and down about 10-15mm and i am guessing it should be steadier than that.
  11. Use transmission fluid or similar coloured oil, slightly thicker than water and allows much better damping of the pulses.. Decrease the size of the restriction in the tube, or just clamp the tube down till the fluid barely moves around. This will allow pressure differential to move the fluid, albiet more slowly, so you just adjust teh carbs a little at a time and wait a few seconds.
    A manometer is by far the most accurate device for this sort of thing.

    Regards, Andrew.