[Healeys] Spark plug color - what do you think

Larry Varley varley at cosmos.net.au
Mon Apr 27 14:28:47 MDT 2015

Hi John, keep in mind that a plug color test is best done after high 
speed cruising, ideally drop the car out of gear and turn off 
immediately while cruising at highway speeds for a while. Then check the 
color of the plugs. You can't hear high speed detonation, and high speed 
detonation is what will cause major damage.
Larry Varley

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