24-10-2019, 06:49 PM
(This post was last modified: 24-10-2019, 06:50 PM by Reckless Rat.)
If you like a broken wrist or thumb then by all means crank your car over with the ignition fully advanced, but the ideal way is to retard it. What you do manually on a Seven is what a later auto advance distributor does for you. The static timing allows for a retarded spark for starting but as engine/distributor speed increases the bob weights advance the ignition to give the correct setting when running.
If you think about it, there is a finite time involved for the spark to occur and the fuel to burn in the cylinder. The faster the engine goes the earlier the spark has to occur in order for the "burn" to be at its best immediately at or just after TDC in order to force the piston down the bore. Too late and you don't get the maximum downward force, too early and it tries to work against itself.
The Lucas DK auto advance distributor gives about 8° full advance (from static) which is fine for a road engine.
If you think about it, there is a finite time involved for the spark to occur and the fuel to burn in the cylinder. The faster the engine goes the earlier the spark has to occur in order for the "burn" to be at its best immediately at or just after TDC in order to force the piston down the bore. Too late and you don't get the maximum downward force, too early and it tries to work against itself.
The Lucas DK auto advance distributor gives about 8° full advance (from static) which is fine for a road engine.