Continuity Tester - Old School

Discussion in 'Sparky's corner' started by gstewart, May 5, 2017.

  1. gstewart

    gstewart Well-Known Member

    I know that using the old school continuity tester (looks like a screwdriver with a lead wire & with a light inside) to test when the points open to fire a cylinder.
    Years ago I saw, on an auto restoration show, use a continuity tester. He set the harmonic balancer to say 10* BTDC on cylinder 1 and then with the tester connected (to what I do not ) rotated the distributor housing until the light came on and initial timing was set.
    Anyone know to what the tester lead wire is attached to and to what does he touch the pointed wire end to? I assume ignition on.
    I would like to try this. Educate me.
     
  2. Ziggy

    Ziggy Well-Known Member

    Basically, the points complete the circuit through the coil primary windings by connecting the (-) wire to ground. The wire between the coil to the points will light a test light, although not full brightness , when the points are open and turn it off when the points close.

    Disconnect the coil to distributor hi tension wire before continuing.

    The old school setup is to connect the test light between ground and the (-) terminal on the coil. Set the crank position to the desired timing, making sure to remove all timing chain slack by ending with the last rotation in engine running direction. Turn the ignition on, rotate the distributor in the normal rotor turning direction (right) until the points close which turns the test light off. Then very slowly turn the distributor to the left until the test light just turns on. Lock the distributor down and proceed from there.

    This will get you in the ballpark for initial timing but has very little overall value to the performance of the engine. There is very good sticky on this board on power timing which thoroughly covers the subject of timing theory and setting procedures, it's worth one's while to learn and follow this tutorial.
     

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