Valve Clearances - Rule of Nine

Vintage Alvis Maintenance

  • Ignition timing and setting up a Magneto on my Alvis TG 12/50

    Valve clearances - Rule of Nine

    My father taught me the “Rule of 9”.
    • If valve #1 is open then valve #8 will be closed…
    • if valve #2 is open then valve #7 will be closed…
    • if valve #3 is open then valve #6 will be closed…
    i.e. the sum of both valves comes to 9.

    • Starting with valve #1 being open - you cannot turn the pushrod around - use the 6 thou feeler gauge to adjust valve #8.

    • Now repeat this exercise until all eight valves have been adjusted to 5 or 6 thou.

    Stacks Image 5789

    This website contains my personal Maintenance schedule based on the late Micky Radford's "The Vintage Alvis Manual" and is supplemented by Lubrication charts from the Alvis TJ 12/50 Instruction Book. These project notes are based purely on my own experience and are not intended as advice or guidance to the reader.