Loss of compression in Series 60 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.
- Move the vehicle requiring test to the chassis dynamometer; refer to OEM guidelines.
- Disconnect air compressor;
- Start the engine.
- Run the engine and bring the engine coolant temperature to normal operating range.
- Run vehicle to full load and rated speed.
- Attach a manometer calibrated to read in. H 2 O, to the oil dipstick opening.
- Measure and record crankcase pressure.
- Shut down engine.
- Remove the vehicle from the chassis dynamometer.
- Review the crankcase pressure test results.
- If the crankcase pressure was greater than 3 in. H 2 O (.75 kPa);
- If the crankcase pressure was less than 3 in. H 2 O (.75 kPa); perform a cylinder compression test.
- Compare the cylinder compression test results to specifications.
- If cylinder pressure is below specifications
- If cylinder pressure is within specification, call Detroit Diesel Technical Service Group.
Worn or Damaged Valve or Cylinder Kit Repair
Perform the following steps for worn or damaged valve or cylinder kit:
- Remove cylinder head;
- Inspect the cylinder head for worn or damaged valves; For repair and replacement procedures
- Inspect the cylinder kit components for worn or damaged liners; pistons or piston rings;
- Verification of repairs made to cylinder valve(s) or cylinder kit components is required;
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:
- Start the engine.
- Run the engine speed up to the occurrence of the misfiring.
- Listen for misfiring cylinder.
- If the engine is not misfiring, no further troubleshooting is required.
- If the engine is misfiring, call Detroit Diesel Technical Service Group.