He said, "The four-valve oil drain-back system on the 4.6 motors is insufficient on modified engines because of the airflow in the crankcase simultaneously working against the drain-back holes on ...

The anti-drainback valve, shown below, makes sure the filter traps oil when the engine isn't running. It's essentially a nitrile or silicone one-way check-valve that prevents oil in a filter ...

The silicone anti-drain back valve makes sure the engine is receiving clean oil once the ignition is started. It has a high-lubricity gasket that provides a safe and leakproof seal.