Calculating total ignition advance
Question:
In an earlier issue of Auto Restorer, John Armstrong said that his GM AC Delco training manual states that
initial (base) timing is not included in an engine’s total ignition advance. On the other hand, Milt Webb’s tune-up advice (on page 11 of the August 2008 issue) states, “Add up the mechanical advance, the vacuum advance and base timing. Now you have total advance...”
So which is it? Should total advance include initial advance or not?
Answer:
The total number for ignition advance should include initial advance as well as all mechanical and all vacuum advance. I have no explanation for why a service manual reportedly says otherwise.
