Manifold vacuum lines

[gbvona]

I am trying to piece together my ride (1970 NADA 3500S) from a bodged conversion, replacing an Oldmobile engine with a 3.9L. I am using the original intake manifold. I am trying to sort out the piping.

There are three small vacuum ports on this manifold (In addition to the brake booster). One I presume goes to the vacuum reservoir for the Smiths HVAC unit. I think one of them was for the Automatic Enrichment Device, which is long gone. (1) What is the third port connected to? And (2) how does the wiper delay unit get vacuum? There is a hose coming out of a wrapped wire bundle, no idea where the other end emerges.

gbvona

 

[cooper1203]

hi, I may be way of base here. but doesn't the distributor take a vacuum for the advance??

coop

 

[P6Disease]

Hello Gbvona,

One goes to the vacuum reservoir for the heater unit, one goes to the air cleaner assembly, for the hot/cold intake flap & the last one goes to the distributor.

Roly.

 

[gbvona]

I get the part about the heat/air unit and the flap on the air cleaner.

However, the distributor vacuum advance should come from the carburetter throat. Does it not? And where does the vacuum for the wiper delay come from? Is it piped out of the heat/air stuff?

Thanks for your help!

gbvona

 

[harveyp6]

And where does the vacuum for the wiper delay come from?

That's not engine vacuum, it's an entirely self contained system.

 

[P6Disease]

On the Nada's, the distributor vacuum connection is made via the three way banjo, there's no vacuum connection on the l/h carb, as on a standard car.

 

[gbvona]

Gotcha, thanks to all for the collective wisdom.

gbvona