i too have had my ignition trials
this is where i have landed. 2 solutions one both or neither of them might work
original solution
1) take dizzy, take it to bits clamp shaft in vice, put a degree wheel over where the rotor fits, fit rotor twist it so it activates the advance, measure, adjust advance travel against your degree wheel. 1 degree in the dizzy is worth 2 at the crank so added a small brass bush to its resting stop, so that the distributor added only what i needed. in my case 6.5 degrees. i could then set it at 15 initial and have 28 total.. 6.5 x2 is 13 13+15 is 28* total, this was done totally focused on not running vacuum advance... then i saw the light......
i then stuck the vacuum onto manifold vacuum via a fitting on just 1 carb, below the thottle plate, A La Alfa romeo alfasud
via a pulse smoother, so it pulls in all the vacuum advance at idle and a small proportion at cruise... advance at idle....mental, but it likes it...advance off idle just the mechanical advance at lift off throttle, at speed mental.. but i can now go an awfully long way on idle mixture with my foot off the gas.... i can roll up to the traffic lights from about 10 miles away, that sluggish weightyness when you lift off the gas is gone, much more like driving a smaller nippy little car .......
2) take a standard dizzy, set it up at total mechanical you need 28-34* 36 in some rare cases, which on mine is 28* check what it is at idle, about 4* BTDC swap springs and until you get 15 degrees at idle then plumb in the vacuum as before.
both achieve more or less the same sensible initial for cam/compression and modern petrol same old total mechanical advance
15 initial bolstered by vacuum up into 30s at idle speed
15 -28 off idle up to max rpm
the second way is achieved just with springs , the first involved mechanical changes to the advance mechanism at the mo. i still think version 1 was best, but have not done anything to version 2 really to make it better. Waiting for mr Moroso to send a kit of springs and small pieces of plastic .
i run Hei with an HEI coil and plug gaps of 45 thou.
HEI failures i had a few and my tacho used to flip out occasionally pinning the needle to the end stop, until i put in the diode.. i was always suss, that it was my alternator killing the modules.... there was nothing wrong with the alternator up to the point where the brushes wore out but i was very suspicious, we are running something closer to a computer in a car with an electrical system only slightly better than a ferguson tractor .
Dave
