Dual Advance Duraspark.

[Bort62]

So I ended up with a dual advance distributor despite my best efforts.

I would assume that one is intended to be hooked up to ported vacuum while the other to manifold.

So which one for which?

Also, Should the PCV valve be hooked to ported or manifold vacuum? Its been a long time since ive played with this stuff and Its the little details you forget first

 

[Anonymous]

What carb are you using?

 

[wallaka]

You sure it's dual advance? I've seen them that have an advance and a retard port on them, usually from the smog era. If so, keep the retard open to atmosphere, and connect the advance to whichever makes it run better. I've heard advocates of both.

The PCV goes to manifold vacuum.

 

[Bort62]

Well, I should rephrase.

It has two ports on the Vac advance can. It looks like one is on either side of the diaphram so I can see one being for retard. If thats the case, thats easy to figure out.

It shouldnt matter what the carb is - the mech curve in your distributor will dictate if you want ported or manifold. IIRC, stock curving looks for ported.

And PCV going to manifold makes sense.

Thanks.

 

[wallaka]

The only reason we ask what carb is if you have one with the Spark Control Valve (only used up to '67) it's almost guaranteed that manifold vac is the way to go. The SCV puts out a funky, load-sensing signal out that doesn't play nice with non-compatible distributors. If you have a later carb, then the ported signal could work well.

 

[Anonymous]

thank you wallaka

 

[Bort62]

Ahh, right. Not used to this funky ford stuff

At any rate, I think i do have one of the SCV carbs but I intended on figuring out a way to get myself real manifold vacuum.

Thanks.

 

[wallaka]

That's easy...just T off of the PCV line or any other vacuum line.

 

[Bort62]

I should have said ported vacuum. A little trickier but I think I can figure it out.

 

[wallaka]

Read the sticky entitled "How the Spark Control Valve Works". It has some suggestions for disabling the valve and getting real ported vacuum.