Non-Linear Vacuum Regulator Valve
Used on some AMC vehicles, this valve combines regulated manifold vacuum at idle speed and carburetor ported vacuum to the ignition spark advance mechanism. It is mounted in line between the vacuum source port and distributor vacuum can.
There are 2 input ports on the NLVR: Intake manifold vacuum and carburetor ported vacuum. One outlet port connects to distributor advance unit. At idle, regulated vacuum is supplied to advance unit (when manifold vacuum is high and ported vacuum is very low). The NLVR regulates vacuum signal so it is between these 2 vacuum source levels at idle. As engine load increases, vacuum signal above 7.5 in. Hg @ 70-80°F, regulator valve switches to ported vacuum output.