Re: 1948 Packard not starting

Posted by Owen_Dyneto On 2020/3/25 20:19:09

Chris, using a timing light to get you set to the original timing spec is fine, but there are reasons that that may no longer be the optimal timing for your engine. For one thing the fuel is entirely different, much higher octane being just one difference. And two, if an engine rebuild involved resurfacing the cylinder head, your compression ratio is now higher. So the question becomes, why not alter your timing to take advantage of those changes and get the additional power they will allow?

I've always thought the best way to get optimal ignition timing is the "by ear" method which will compensate for any such changes. What you want is the earliest possible timing consistent with just the faintest hint of spark ping or preignition on a hard pull in high gear at modest speed. In practice, get a passenger or roll down the passenger front window. Proceed in high gear up a modest grade at 30-40 mph and give the car full throttle. Keep advancing the timing until you can just faintly hear a hint of ping. Be sure to use the grade of gasoline you expect to normally use. And be sure the distributor vacuum advance unit is functional.

If you are so inclined, after you've established this new optimal timing, put your light back on and establish a reference of the new timing.