Posted by Sparks on February 04, 1999 at 15:13:46:
In Reply to: Re: Where is the vacuum source? posted by T.L. on February 04, 1999 at 13:46:15:
I became familiar with it when I had my cooling system problems during the new year. The lines were not routed as you describe, and were replaced the way they were. I have a feeling that a trip to the library for a full diagram (chilton is not complete)may be in order here.
The one to the manifold is the only one routed as you describe. The line going into the dist advance (single diaphram)comes from under the rear carb. I can't recall without looking where the other two lines go off of the valve.
This answer search may have uncovered a bigger problem than just a missing line.
: I removed mine and installed an open element air cleaner years ago on my '73. To answer your question; there is a heat activated vacuum switch/valve that is screwed into the top of the water neck on the intake manifold, where the upper radiator hose goes. It has 3 vacuum fittings on it. One is connected to the full manifold vacuum, one goes to your distributor vacuum advance, and the other goes to your air cleaner sensor. Then from the sensor to the vacuum motor on the snorkle. When you start your car cold, full manifold vacuum is applied to the snorkle motor and holds the door shut so it can only suck in warm air blowing past the exhaust manifold heat stove. When the engine coolant reaches a certain temperature, the valve in that vacuum switch shuts off the vacuum to the air cleaner and the spring loaded "door" opens, letting in fresher air. I do NOT reccomend sticking a rag in your air cleaner in any weather. This will obstruct airflow and rob power as well as make the engine run "rich"....
: : I like your ingenuity. It is not so cold here as to use such measures. I just want to hook it back up for starting help.