Lead Additive - yes or no?

Discussion in 'Classic Buicks' started by Paul L., Sep 24, 2020.

  1. BQUICK

    BQUICK Gold Level Contributor

    Today's 93 is hardly any more octane than regular in the old days. Plus it has ethanol so it runs leaner and no lead. 68 was designed for leaded premium. Lead would help if you put a lot of miles on it otherwise you will get valve seat recession. I would at least put some Marvel Mystery oil in the gas.

    If you really want to pamper it mix 93 with 110 Sunoco leaded 50/50. Costly but it's only money......
     
    Brett Slater likes this.
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  3. Gary Bohannon

    Gary Bohannon Well-Known Member

    Read Larry's info!
    The primary benefit of lead for our engines:
    1. Lubrication of valve guides
    2. Cushion the valve seats and prevent valve recession.
    If you have bronze valve guides and steel valve seats, you do not need lead or lead additive.
    TA aluminum heads will solve those problems.

    As for engine detonation or preignition.
    1. No full throttle above 180 coolant temperature.
    2. Add a cold air intake.
    3. Block the intake heat passages.
    4. Limit mechanical timming to 32 or 34 degrees.
    5. Install a cooler range spark plugs.
    6. Richen the carb jetting slightly, and be sure fuel delivery is sufficient and gas tank is vented.
    7. Be sure there are no exhaust restrictions, especially a stuck heat riser valve.

    I run 7.50 1/8th mile on stock Buick pistons, .080" quench, about 9.5 CR,
    91 octane (NO ETHANOL) gas, 34 max timing, 3750 lbs 67 GS, NO DETONATION.
    Did that with iron heads and now TA heads.
     
    Last edited: Jan 1, 2021
  4. 1970BlackBird

    1970BlackBird 1970 Buick Skylark Sedan, "Rosaline"

    I usually run 93 Octane with a little 110 for a good measure. Peppy and happy on those 100+ mile drive days.
     

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