Non-Linear Vacuum Regulator (NLVR) Valve

PURPOSE
On engines equipped with a NLVR valve, distributor vacuum advance is controlled primarily by regulated vacuum. Regulation is determined by engine load.

OPERATION
The NLVR valve has two input ports (one from manifold vacuum and one from carburetor ported vacuum sources) and one outlet port to CTO valve. Under low-load or no-load operating conditions, the valve provides regulated vacuum. Under these conditions, manifold vacuum is high and there is little or no ported vacuum. The NLVR valve provides a vacuum level that is somewhere between the two vacuum levels, determined by the calibration of the valve. As engine load increases and ported vacuum increases above the regulated value, the valve switches to ported vacuum.