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Home › Chevrolet › 1966 › C10 Panel › Repair and Diagnosis (Single Page) › Engine Mechanical › Mechanical › Crankcase Ventilation Systems › System Checking › Engine Drop Method

Engine Drop Method

  1. Connect a tachometer to engine, set parking brake, start engine.
  2. Disconnect hose or fitting leading to intake side of ventilation valve, and cover intake opening of valve with finger.
  3. Engine speed should drop at least 50 RPM. If less, valve metering hose or orifice is blocked.
Fig 1: 1966-67 VENTED CAP VENTILATION SYSTEM (327" V8)
G09340476Courtesy of GENERAL MOTORS COMPANY
Fig 2: 1966-67 OPEN VENTILATION SYSTEM (396" & 427" V8)
G09340477Courtesy of GENERAL MOTORS COMPANY
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