[Richard in Florida]

Originally Posted by 36tbird

I guess I am just asking why you need an adjustable canister versus a non-adjustable. Is the adjustment a matter of sensitivity so that it reacts quicker at a lower vacuum or what?

No, it's not a matter of sensitivity; it's a matter of how many degrees of advance the canister produces. The change from activated state to not activated state is plenty fast in the adjustables sold by Accel, Crane, and others.

The canister produces advance by rotating the entire breaker plate inside the distributor. By inserting an allen key into the hose snout of the canister you can adjust the length of the canister's pulling stroke, thus the amount of additional advance it produces.

If you use a non-adjustable canister, you're stuck with whatever amount of advance is built into it.