Distributor Spark Thermal Vacuum Valve (DS-TVV)

This valve supplies manifold vacuum through a distributor spark vacuum delay valve (DS-VDV) to the distributor when the carburetor air inlet temperature is below the specified temperature. The DS-VDV maintains vacuum advance during rapid throttle opening to improve engine response during cold engine operation. When engine coolant temperature is above the calibration temperature, ported vacuum is supplied to the distributor through a distributor spark thermal vacuum switch (DS-TVS) with no additional vacuum controls.