MBE 4000 DDEC VI Troubleshooting – Section 10.4 Worn or Damaged Intake/Exhaust Valve or Cylinder Kit

Section 10.4
Worn or Damaged Intake/Exhaust Valve or Cylinder Kit

To determine if a worn or damaged cylinder kit is causing excessive blue exhaust smoke, perform the following:‪

1. Move the vehicle requiring testing to the chassis dynamometer; refer to OEM guidelines.
2. Disconnect and remove the air compressor; refer to MBE 4000 Service Manual (6SE420), Chapter 11, “Special Equipment”.

   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.‪

3. Start the engine.
4. Run the engine and bring the engine coolant temperature to normal operating range, approximately 88-96°C (190-205°F).
5. Run the vehicle to full load and rated speed.
6. Measure and record crankcase pressure. Refer to "2.1 Crankcase Pressure Test" .
7. Shut down the engine.
8. Remove the vehicle from the chassis dynamometer.
9. Review the crankcase pressure test.
   1. If the crankcase pressure was greater than 0.62 kPa (2.5 in. H₂ O), refer to "10.4.1 Worn or Damaged Intake/Exhaust 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" .
10. Compare the cylinder compression test results to specifications, listed in Table "Compression Pressure Test Data" .
    1. If cylinder compression pressure is below specifications, refer to "10.4.1 Worn or Damaged Intake/Exhaust Valve or Cylinder Kit Repair" .
    2. If cylinder compression pressure is within specifications, call Detroit Diesel Customer Support Center at 313-592-5800.

       Description‪	Pressure in kPa (psi)‪
       Compression Pressure at Starter Speed‪	2800 (406)‪
       Permissible Difference between Individual Cylinders‪	400 (58)‪

       Table 2. Compression Pressure Test Data

Section 10.4.1
Worn or Damaged Intake/Exhaust Valve or Cylinder Kit Repair

Perform the following steps for worn or damaged intake/exhaust valves or a cylinder kit:‪

1. Remove the cylinder head; refer to MBE 4000 Service Manual (6SE420), Chapter 1, “Engine — Cylinder Head”.
2. Inspect the cylinder head for worn or damaged valves and worn or damaged valve stem seals; refer to MBE 4000 Service Manual (6SE420), Chapter 1, “Engine — Valves”.
3. Inspect the cylinder kit components for worn or damaged liners, pistons or piston rings; refer to MBE 4000 Service Manual (6SE420), Chapter 1, “Engine — Cylinder Block”.
4. Verify repair to cylinder valve(s) or cylinder kit components; refer to "10.4.1.1 Test Engine with Repairs Made to Correct Worn or Damaged Intake/Exhaust Valve or Cylinder Kit" .

Section 10.4.1.1
Test Engine with Repairs Made to Correct Worn or Damaged Intake/Exhaust Valve or Cylinder Kit

Perform the following to determine if the repaired intake/exhaust valve or cylinder kit has resolved the excessive crankcase pressure:‪

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 and bring the engine coolant temperature to normal operating range, approximately 88-96°C (190-205°F).
3. Run the vehicle to full load and rated speed.
4. Visually inspect exhaust for excessive blue smoke.
   1. If the engine exhaust smoke emission appears normal for a rebuilt engine, no further troubleshooting is required. Shut down the engine.
   2. If the engine exhaust smoke emission is excessively blue, shut down the engine. Call the Detroit Diesel Customer Support Center at 313-592-5800.