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Thread: Timing advance for HEI in a 250 six with overdrive

  1. #1
    VCVC Member TurboVan's Avatar
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    Timing advance for HEI in a 250 six with overdrive

    I noticed that my ebay HEI distributor timing advance curve seemed a little steep, it would ping when it shifted into O/D at low speeds, so the timing was coming in too quick.
    Upon inspection, the springs it comes with are quite weak, so weak in fact, that they don't really snap the weights all the way back unless the engine is stopped!
    So I ordered this kit from Summit:

    https://www.summitracing.com/parts/s...iABEgKl7fD_BwE

    It has three sets of springs, gold, black, and silver, in order of increasing strength.
    Since I only needed a little less timing, I replaced only one spring with one of the black (medium strength) springs in the kit, then cleaned and lightly re-greased all the moving parts.
    I did not change the weights or anything else.
    Seemed to work perfectly, it actually idled slower because the weights were now returning to their fully-retracted position, and no more pinging!
    She will lug smoothly up from 30 MPH, locked-up in 4th gear, with no bucking.
    Last edited by TurboVan; 06-12-2018 at 11:09 PM. Reason: why not?
    Keep one foot in the gutter, one fist in the gold...

    '65 Panel, with turbocharged 327 (originally 153 four), TH400 (originally 3-speed), and 3.31 '67 Camaro 12 bolt rear (my first car, 1970)
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    '69 Sportvan 108 with turbocharged original 250 six and 700R4 (originally Powerglide), 3.73 rear, starred in eight Taco Bell commercials
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  2. #2
    VCVC Member jrinaman's Avatar
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    I had so many issues with my ebay distributor that I just pulled it and found a good used original. it sounds as if yours is good now but if you dig into it again, consider setting timing at 2000-2500 rpm and working backwards. with no vacuum, 36 degrees at 2k and change springs or weights o get timing at idle here you want it. don't worry about factory spes, if it starts easier with less advance, set it there. once you hit the gas, it will advance to where it need to be 'if' timing at higher rpm is correct. after all that is done, you can start playing with the adjustable vacuum advance.
    '64 chevy, 292 40 over, 206/526 cam, 2004r trans. 9.75:1, dual webbers, Langdon cast headers, 1.94 valves

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