VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 malfunctioning vacuum advance?

Hello Everyone,

How can I tell that my vacuum advance is functioning properly? I believe you should see the distributor shift as you increase rpm's, but obviously I need clarification!

thanks!

Steve

At idle the advance is recieving no vacuum.At about 1200 rpm it recieves full vacuum.Watch and see if the distributor rotates when you bring the engine up from idle speed.The vacuum advance will suck it ahead.If you crack the throttle open quickly it will retatrd ( no vacuum) a bit then advance.

Other than originality sakes, that retarding dashpot is a nuicance if you want to take advantage of 87 octane fuel.

The vacuum advance actually advances the timing when the engine is not under load (during high vacuum)...This allows the engine to run cooler and produce better gas milage.At extreem high speeds (over 60 MPH) it is inoperative the the centrifical weights in the distributor have the timing advance as much as possible.I would advise to have it operating.If not the mechanical advance curve would need to be changed.