1978 Cobra Vacuum Ported Switch Question

[Vic1978]

Help needed. I’ve done research on vacuum port switches. My understanding is, they get to a certain temperature (unk temp), they open and vacuum is introduced to whatever they are hooked up to.

I see 3 different type switches on this stock intake. One 3 port and two 2 port. The 2 ports are next to each other but physically are shaped different at the top. I

s there a difference in all three switches? Do they all get heat from the water source through the intake water ports as opposed to exhaust ports?

I’m not a mechanic and I’m trying to figure this out.

In advance, thanks for the help.

 

[jozsefsz]

Been a long time since mine has had the switches, but as I recall they're all water-heated. Exhaust heat would melt the snot out of them, that I've only ever seen used for heating the choke (via a thin tube) or I'd guess you could run an EGR from it (or AIR injection into it) if you didn't have other provisions.

 

[Vic1978]

Thanks for your reply, makes sense. I’m trying to put all of the smog stuff back and I’m trying to connect all it’s necessities as they should go but not sure where they all go. I’ll keep researching.

Thanks again.

 

[COBRA 7]

Port 1 and 2 are temp units heated from the coolant running through the intake.

Port 3 is a vacuum port in the intake runner. Has vacuum all the time. For vacuum booster for brakes. Also for vacuum modulator on automatic transmission.