Section 4.6 Worn or Damaged Valve or Cylinder Kit

Section 4.6
Worn or Damaged Valve or Cylinder Kit

Loss of compression in MBE 900 engines may result from a variety of sources, including worn or broken fire or compression rings, holes in pistons, leaky valves, scored or worn cylinder walls, leaky or broken gaskets and cracked cylinder heads or cylinder liners. The detection and elimination of the cause or causes 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. Remove air compressor; refer to MBE 900 Service Manual (6SE9007), special equipment chapter.
  3. Perform a crankcase pressure test. Refer to "2.1 Crankcase Pressure Test" .
  4. Remove the vehicle from the chassis dynamometer.
  5. Review the crankcase pressure test results.
    1. If the crankcase pressure was greater than 0.62 kPa (2.5 in. H2 O),refer to "4.6.1 Worn or Damaged Valve or Cylinder Kit Repair" .
    2. If the crankcase pressure was less than 0.62 kPa (2.5 in. H2 O), perform a cylinder compression test. Refer to "2.2 Compression Pressure Test" .
  6. Compare the cylinder compression test results to specifications:listed in Table "Compression Testing" .
    1. If the cylinder compression is below specifications, refer to "4.6.1 Worn or Damaged Valve or Cylinder Kit Repair" .
    2. If the cylinder compression is within specifications, call Detroit Diesel Customer Support Center at 313–592–5800.

Section 4.6.1
Worn or Damaged Valve or Cylinder Kit Repair

Perform the following steps to determine a worn or damaged valve or cylinder kit:‪

  1. Remove cylinder head; refer to MBE 900 Service Manual (6SE9007), engine chapter.
  2. Inspect the cylinder head for worn or damaged valves; refer to MBE 900 Service Manual (6SE9007), engine chapter.
  3. Inspect the cylinder head components for worn or damaged liners examine the pistons or piston rings.
  4. Verification of repairs made to cylinder valve(s) or cylinder kit components is required; refer to "4.6.1.1 Verification of Repair for Worn or Damaged Valve or Cylinder Kit" .
Section 4.6.1.1
Verification of Repair for Worn or Damaged Valve or Cylinder Kit

Perform the following steps to determine if the repaired valve or cylinder kit resolved the misfiring cylinder condition:‪

warning

PERSONAL INJURY

To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

  1. Start the engine.
  2. Run the engine speed up to the occurrence of the misfiring.
  3. Listen for misfiring cylinder.
    1. If the engine is not misfiring, no further troubleshooting is required.
    2. If the engine is misfiring, call Detroit Diesel Customer Support Center (313-592-5800).


EPA07 MBE 900 DDEC VI Troubleshooting Guide - 6SE580
Generated on 10-13-2008

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