Distributor Spark Vacuum Delay Valve (DS-VDV)

This valve has two chambers with an orifice and one way check valve between them. This arrangement allows free air passage toward source vacuum and restricted (delayed) air passage toward the controlled unit or units.
Ports 1 and 2 are connected to one chamber and connected to vacuum source. Ports 3 and 4 are connected to the other chamber and are subject to the delay operation of the valve.