Series 50

Section 19.6 Worn or Damaged Valve or Cylinder Kit

Section 19.6
Worn or Damaged Valve or Cylinder Kit

A loss of cylinder pressure can cause increased oil consumption. The detection and elimination of cylinder pressure losses is vital to engine life and efficient operation. To assist the mechanic in effectively measuring the loss of cylinder pressure, and locating the source of abnormal leaks in individual cylinders, the following test procedure has been developed.‪

  1. Move the vehicle requiring test to the chassis dynamometer; refer to OEM guidelines.
  2. Disconnect air compressor, refer to "10.1.2 Cleaning and Removal of Air Compressor" .
  3. Start the engine.
  4. Run the engine and bring the engine coolant temperature to normal operating range.
  5. Run vehicle to full load and rated speed.
  6. Attach a manometer, refer to "29.1 Proper Use of Manometer" , calibrated to read in inches of mercury, to the oil dipstick opening. Measure and record the crankcase pressure; refer to "29.3 Crankcase Pressure Test (Governed Speed No Load)" .
  7. Shut down engine.
  8. Remove the vehicle from the chassis dynamometer.
  9. Review the crankcase pressure test results.
    1. If the crankcase pressure exceeds 3 in. H2 O (0.75 kPa), repair worn or damaged valve(s) or cylinder kit; refer to "19.6.1 Worn or Damaged Valve(s) or Cylinder Kit(s) Repair" .
    2. If the crankcase pressure was less than or equal to 3 in. H2 O (0.75 kPa), perform cylinder compression test; refer to "29.2 Cylinder Compression Test" .
  10. Compare the cylinder compression test results to specifications.
    1. If the cylinder compression is below specifications, repair worn or damaged valve(s) or cylinder kit; refer to "19.6.1 Worn or Damaged Valve(s) or Cylinder Kit(s) Repair"
    2. If the cylinder compression is within specification, call Detroit Diesel Technical Service Group.

Section 19.6.1
Worn or Damaged Valve(s) or Cylinder Kit(s) Repair

Perform the following steps to repair worn or damaged valve(s) and cylinder kit(s):‪

  1. Remove cylinder head; refer to "1.2.2 Removal and Cleaning of Cylinder Head" .
  2. Inspect the cylinder head for worn or damaged valves; refer to "1.2.3 Inspection of Cylinder Head" .
  3. Inspect for worn or damaged cylinder kit components:
    1. Inspect cylinder liner for damage, refer to "1.20.1 Repair or Replacement of Cylinder Liner" .
    2. Inspect piston and piston rings for damage, refer to "1.17.3.1 Inspection of Piston and Piston Ring" .
  4. Perform an oil consumption test report; refer to "19.6.1.1 Test Engine for Reduced Oil Consumption" .
Section 19.6.1.1
Test Engine for Reduced Oil Consumption

Perform a lube oil consumption report; refer to "29.5 Lube Oil Consumption Report" .‪

  1. Review the oil consumption report.
    1. If the oil consumption report data is within specifications, check for defective air compressor. Refer to "19.4 Defective Air Compressor" .
    2. If the oil consumption report data is not within specifications, call Detroit Diesel Technical Service Group.


Series 50 Service Manual - 6SE50
Generated on 10-13-2008

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