PCV Valve Cutaway Diagram: Low vs High Speed Operation (Ford Bronco)

This document is a schematic cutaway illustration showing the internal operation of a PCV (Positive Crankcase Ventilation) valve under two engine operating conditions. Two cross-section views of the valve are stacked vertically. In both views, flow arrows enter from the left, labeled 'FROM CRANKCASE AND/OR ROCKER ARM COVER,' pass through the valve body containing a spring-loaded plunger, and exit to the right toward an arrow labeled 'TO INTAKE MANIFOLD.' The top illustration is captioned 'LOW SPEED OPERATION: HIGH MANIFOLD VACUUM,' showing the valve plunger pulled toward the manifold side by strong vacuum, restricting flow. The bottom illustration is captioned 'HIGH SPEED OPERATION: LOW MANIFOLD VACUUM,' showing the plunger positioned so the spring is extended, allowing greater flow through the valve. A reader can learn from this diagram how the PCV valve's internal tapered plunger and spring modulate crankcase vapor flow into the intake manifold depending on manifold vacuum level and engine speed. The document contains no year, make, model, engine, or part number information, it is a generic PCV valve operation diagram uploaded to a 1992 Ford Bronco gallery.