Tachometer Filter

Discussion in '1967-1972' started by mel 55_1, Dec 13, 2017.

  1. mel 55_1

    mel 55_1 Member

    Joined:
    Apr 1, 2004
    Messages:
    98
    Location:
    England
    Anyone have experience with a Tachometer Filter?

    I have a stock tacho in my ’69 C10, but the po installed a 350 with a HEI unit so it just reads a constant 2500 rpm. From what I can tell I need to ‘filter’ the signal from the HEI Tachometer feed to the dash. Anyone done this, what did you use and how simple a fix was it?

    Thanks...
     
  2. Lakeroadster

    Lakeroadster Member

    Joined:
    Jan 23, 2011
    Messages:
    1,577
    Location:
    Central Colorado
    I bought an aftermarket tachometer Auto Meter tach for my '69 Camaro and the readings were erratic and spiked frequently. I called the Auto Meter Service phone number and one of their technicians instructed me to install a 10K ½ watt resistor in the green wire going to the coil. I purchased the resistor and put it on the coil wire.

    It worked.. but my Camaro has the factory stock distributor... and an after market tach.. That may or may not work for you.

    You might want to call Auto Meter Service 866.248.6356. They seem to be car-guys....

    Good Luck!
     
  3. mel 55_1

    mel 55_1 Member

    Joined:
    Apr 1, 2004
    Messages:
    98
    Location:
    England
    Thanks for this though I'm kinda the other way around - stock tach / after market ignition. If yours worked with a resistor, maybe I need the opposite, whatever that is.
     

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