Vacuum Deceleration Valve: Description

The distributor vacuum advance control valve (deceleration valve) is incorporated in the distributor vacuum system to provide additional control of ignition timing. It is used in conjunction with the dual diaphragm distributor. It is connected in the vacuum line to the distributor vacuum unit and has two vacuum input lines, one from the carburetor, and the other from the intake manifold. Vacuum sources can be switched as engine conditions require.