Vacuum Advance/Retard Systems: Description

The vacuum advance system operates in response to engine coolant temperature and transmission gear position to activate the vacuum advance mechanism. System consists of a solenoid valve, vacuum (amplifier) control valve, transmission switch, thermal Switch, and calibrated orifice, all common to the EGR system.

The 1977-78 R-17 Gordini vacuum advance/retard system is used to control the application of distributor vacuum advance and retard under varying engine operating modes. System consists of a distributor with vacuum advance/retard units, throttle plate switch, vacuum reservoir, solenoid switches, relay, and thermal switch and vacuum venting valve.