It's simply a vacuum diaphragm, when the is vacuum suck the air out of it, it moves in compressing a
spring and when the vacuum is removed and it rises back up to atmospheric pressure the spring pushes
it back to its stop.
If you mean by intermittent, can it operated in between full vacuum advance and no vacuum advance,
yes. I does operate anywhere in between depending on the strength of the vacuum signal.
Denny graham
Sandwich, IL
