Piston Engines

Download the full database via torrent (~1.1 TB) | Download Brad's custom LEMON patches

The PCV system includes 2 hoses and a PCV valve. Air normally flows out the valve cover hose, through the PCV valve and into the combustion chambers. A hose from the air cleaner to the valve cover supplies fresh air to the crankcase.

When intake manifold vacuum drops due to heavy loads, the amount of blow-by exceeds the capacity of the PCV valve. Air then flows directly from the valve cover into the air cleaner and carburetor. When the engine is not running, the PCV valve is closed and vapors are stored in the crankcase.