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Home >> Chevrolet >> 2015 >> Camaro LS, Standard Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Engine Mechanical - 6.2L (L99 LS3 LSA) Or 7.0L (LS7) - Description And Operation) >> Description and Operation >> Camshaft Position Actuator and Solenoid Valve Description >> CMP System Lubrication Flow and Actuator Operation

CMP System Lubrication Flow and Actuator Operation

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Fig 1: Cutaway View Of Actuator
GM2008541Courtesy of GENERAL MOTORS COMPANY
  1. Oil enters the camshaft at the second main bearing journal (1).
  2. Oil travels through the camshaft into the CMP actuator valve check ball (2) and filter (3).
  3. Oil exits the valve and travels through the internal passages of the camshaft (4).
  4. Oil exits the camshaft and enters the actuator oil entry ports.
  5. Oil travels through the actuator and is directed back into the valve (5).
  6. Valve spool position directs oil to the advance or retard passages of the actuator.

The valve may also, under certain conditions, be positioned in a neutral position with no flow to either the advance or retard passages of the actuator.

Fig 2: Identifying Actuator Passages
GM2008542Courtesy of GENERAL MOTORS COMPANY
  1. Oil flows from the camshaft into the valve inlet (3) through the internal check ball and filter.
  2. Oil exits the valve (2) and travels within the internal passages of the camshaft into the entry ports (7) of the actuator.
  3. The center oil groove of the actuator is pressurized and oil reenters the valve (1).
  4. Valve spool position directs oil out of the valve advance (5) or retard (4) ports to the actuator.

The valve may also, under certain conditions, be positioned in a neutral position with no flow to either the advance or retard passages of the actuator.

Fig 3: View Of Advance And Retard Cavities
GM2008543Courtesy of GENERAL MOTORS COMPANY
  1. Pressurized oil enters the retard cavities (2) of the actuator and moves the park pin (3) from the locked position.
  2. As pressure increases within the retard cavities (2), the rotor and camshaft rotate counter clockwise retarding valve timing.
  3. As the duty cycle decreases, the spool is repositioned and oil is sent to the advance cavities (1), rotating the rotor and camshaft clockwise, advancing valve timing.
    • With a 0 percent duty cycle signal to the magnet, the spool is positioned in the fully extended position and there is full flow to the advance cavities of the actuator. As duty cycle increases to near 50 percent, flow to the advance cavities is decreased.
    • With a 50 percent duty cycle, the spool is positioned neutral, with no flow to either the advance and retard cavities.
    • With a 51-100 percent duty cycle, the spool is positioned to provide oil flow to retard cavities. As the duty cycle increases, the flow to retard cavities increases.
    • With a 100 percent duty cycle, there is full flow to the retard cavities of the actuator.
    • The above duty cycle percentage values are only a guideline, as the actual duty cycle values may vary based on engine oil temperature, solenoid magnet coil temperature, magnet coil resistance, and other specifics.