Terry Tanner gave me a few tips on timing which I would like to pass along.
He said the factory recommendation for timing represents an average and will
not be optimum for most engines. They recommended a timing point based on
emissions and it is better to advance the timing if you care more about
performance and mileage than minimizing emissions.
Best timing also depends many factors such as engine condition, manufacturing
variations, altitude, gas type, and any modifications (such as replacing the
carburetor).
He says the best way to set timing is with a vacuum gauge rather than a timing
light. Hook up a vacuum gauge and turn the distributor to advance the timing
until you find the point where vacuum is maximized (should be around 21 pounds
on the 351). That's the best timing point at idle speed, but to avoid pinging
you need to retard the timing until vacuum drops three pounds. Take it for a
drive to see if it pings and retard the timing a little more if it does. The
best test for pinging is to drive about 20 MPH in third gear than slowly
accelerate. That's when the engine is heavily loaded and most likely to ping.
Scott Isenses
///
/// bricklin@autox.team.net mailing list
///
|