adjusting vac can timing

Interesting read. really good info. But I think it's a little off on the vaccum adjustment description tho. You are not adding or removing degrees of advance. You are adding or reducing tension on the preload spring. That means it takes a higher or lower vaccum signal to move the diaphram the same amount to get your desired number of degrees. The vaccum can always has the same amount of movement, and the degrees it adjusts is usually stamped into the arm itself. So by adding all the preload, you make it too hard for the engine to get the vaccum advance in. (like unplugging it at that point.)