Jon, flushed with success from uploading my 'engine won't start' troubleshooter yesterday, I will now attempt to upload a Lucas training course which I think you might find informative. See the section on advance mechanism.
lucascourse3.pdf (Size: 2.17 MB / Downloads: 61)
The ideal of course would be to know what springs were fitted originally to the Seven distributor, but failing that, the advance curve which was aspired to.
This might be of interest too :
"In the DK4A distributor, fitted with heavy “leaden” weights, the springs were relatively heavy items, provided as a matched pair, and which gave a more or less “straight line” progression from full retard to full advance as the speed of the engine increased, and until the total advance was checked by the stops in the action plate."
Source : http://www.da7c.co.uk/technical_torque_a...nce_di.htm
This article suggests there should be a linear increase in advance up to 1000rpm or so, at which point it maxes out (at +8 degrees).
lucascourse3.pdf (Size: 2.17 MB / Downloads: 61)
The ideal of course would be to know what springs were fitted originally to the Seven distributor, but failing that, the advance curve which was aspired to.
This might be of interest too :
"In the DK4A distributor, fitted with heavy “leaden” weights, the springs were relatively heavy items, provided as a matched pair, and which gave a more or less “straight line” progression from full retard to full advance as the speed of the engine increased, and until the total advance was checked by the stops in the action plate."
Source : http://www.da7c.co.uk/technical_torque_a...nce_di.htm
This article suggests there should be a linear increase in advance up to 1000rpm or so, at which point it maxes out (at +8 degrees).