Dual vacuum dizzy info request: 70's points

[powerband]

On an early 70's points dizzy with the dual vacuum setup, where are the proper OEM ports for the two vac. lines?.

>The advance side of the vac chamber vac hose connects to the__________.

>The - nearer distrib. body (retard - pull back ?) vac hose connects to________.

They can't both go to the manifold vac block or it wouldn't work would it?. I have one with the "retard" side unhooked and I can't remember the OEM plumbing. Original carb was a YF, I can't remember if it needs ported vac and manifold or if original carb had two types of ported vac source.

Thanks

Powerband 8)

 

[fmartin_gila]

Hook up your "advance" side to ported vac, I would just leave the "retard" side open and see how it works. IIRC the retard was for emissions.
Fred

 

[powerband]

Hook up your "advance" side to ported vac, I would just leave the "retard" side open and see how it works. IIRC the retard was for emissions.
Fred

Fred,

Yeah, that's how I'm running dizzy on the Pursuit 170 - 5200 - H/W. Improbcat dropped by in his proud '62 Comet with the recent MAv 200/C4/8" conversion and was experimenting.

But how is the OEM vac setup. ' tryin to confirm question...


Thanks
Powerband

 

[66 Fastback]

The vacuum switch tee was used as another emission control device. It was used in conjunction with the dual vacuum advance canister on the distributor. While the engine was warming up, it sent full manifold vacuum to the retard side of the distributor canister. This retarded the spark advance resulting in higher combustion temperatures which had the effect of warming up the engine faster and burning some of the otherwise unburned hydrocarbons during the warm-up period. Once the engine coolant was warm, the vacuum switch closed off the manifold vacuum port signal at the tee, and very little or no vacuum was sent to the retard side of the vacuum canister. Simon posted a nice drawing of the vacuum tee hookup on this thread.
http://fordsix.com/forum/viewtopic.php? ... uum+switch
Doug

 

[powerband]

The vacuum switch tee was used as another emission control device. It was used in conjunction with the dual vacuum advance canister on the distributor. While the engine was warming up, it sent full manifold vacuum to the retard side of the distributor canister. This retarded the spark advance resulting in higher combustion temperatures which had the effect of warming up the engine faster and burning some of the otherwise unburned hydrocarbons during the warm-up period. Once the engine coolant was warm, the vacuum switch closed off the manifold vacuum port signal at the tee, and very little or no vacuum was sent to the retard side of the vacuum canister. Simon posted a nice drawing of the vacuum tee hookup on this thread.
http://fordsix.com/forum/viewtopic.php? ... uum+switch
Doug

Well the pic link doesn't work but I get what you're saying. I forgot about the vac swich since the head is different anyway.

Thanks!
Powerband

 

[66 Fastback]

I forgot the picture was not there any more. But basically the distributor ran off of the ported vacuum source. Without the vacuum switch, if you had the ported source hooked to advance and the manifold source hooked to the retard, then you would get little to no vacuum advance since manifold vac is greater or equal to ported vacuum throughout the rpm range.
Doug