I have a weber 45mm sidedraft carb, my question is there is no more vaccum ports. So how do i hook up the distributer advance(2)?. Mazdatrix said to leave them unhooked, does this sound right. where do i set the timing so i dont hurt my engine at high revs?.

 

Leave them unhooked, but don't plug the nipples on the vacuum pots. You have to unhook your vacuum advance to set your timing anyways. It only has an effect when your foot is off the gas, no effect at wide open throttle. So you can just set your timing the way you normally do.

I believe the vaccuum advance mainly has to do with helping those catalytic converters that you don't have anymore to do their job. You'll notice your car will idle smoother without the vacuum advance, but emmissions will be worse.

 

Yeah, when you're at part throttle, the manifold is under vacuum and the rotors (almost said cylinders! uh-oh) don't fill all the way, so they can stand to run more advance. The vacuum advance has its most effect at low throttle openings and does nothing at full throttle, because there's little/no vacuum.

It's just like if you have a turbo and you have to retard timing under boost.

That said...can't tell the difference when running no vacuum advance. Still get stupid good mileage. I think the staggered-firing dual spark setup that Mazda has really takes care of it, not like most boingers that have only one spark so it HAS to be timed JUST right. Hell, for us, if the leading don't get it all, the trailing will. And if running direct fire, the leading firing a second time gets the rest