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.
1. Move the vehicle requiring test to the chassis dynamometer; refer to OEM guidelines.
2. Disconnect air compressor; refer to the appropriate service manual, special equipment chapter.
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 calibrated to read in kPa (in. H 2 O), to the oil dipstick opening.
7. Measure and record crankcase pressure. For crankcase pressure guidelines refer to Service
Information Letter 02 TS-20 found on the DDC extranet.
8. Shut down engine.
9. Remove the vehicle from the chassis dynamometer.
10. Review the crankcase pressure test results.
[a] If the crankcase pressure was greater than 1.25 kPa (5 in. H 2 O); refer to section 3.5.1.
[b] If the crankcase pressure was less than 1.25 kPa (5 in. H 2 O); perform a cylinder
compression test. Refer to section 3.5.1.2.
11. Compare the cylinder compression test results to specifications.
3.5.1
[a] If cylinder pressure is below specifications, refer to section 3.5.1.
[b] If cylinder pressure is within specification, call Detroit Diesel Customer Support Center (313-592-5800).
Worn or Damaged Valve or Cylinder Kit Repair
Perform the following steps for worn or damaged valve or cylinder kit:
1. Remove cylinder head; refer to the appropriate service manual, engine chapter.
2. Inspect the cylinder head for worn or damaged valves; refer to the appropriate service
manual, engine chapter. For repair and replacement procedures, refer to the appropriate
service manual, engine chapter.
3. Inspect the cylinder kit components for worn or damaged liners, pistons or piston rings;
refer to the appropriate service manual, engine chapter.
4. Verification of repairs made to cylinder valve(s) or cylinder kit components is required;
refer to section 3.5.1.1.
3.5.1.1
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:
1. Refer to section3.5 for the exhaust caution before preceding. Start the engine.
2. Run the engine speed up to the occurrence of the misfiring.
3. Listen for misfiring cylinder.
[a] If the engine is not misfiring, no further troubleshooting is required.
[b] If the engine is misfiring, call the Detroit Diesel Customer Support Center 313–592–5800.
3.5.1.2
Cylinder Compression Test
Perform the following steps for a compression test on a Series 60 Engine:
1. Start and run the engine until normal operating temperature is reached. Stop the engine.
2. Disconnect the batteries.
3. Disconnect the fuel pump feed line from the fuel tank. Place a suitable container under the line to catch the spilling fuel. Turn the 1⁄4 turn valve off on the outlet fitting of the secondary fuel filter.
4. Disconnect the fuel supply line to the cylinder head. Place a suitable container under the line to catch the spilled fuel. Disconnect the fuel return line from the doser valve and place a suitable container under the line to catch the spilled fuel.
5. Blow low pressure regulated air no more than 207 kPa (30 psi ) into the inlet fitting for 20
to 30 seconds or until all the fuel is purged from the head.
6. Clean and remove the rocker cover, it is not necessary to remove the bottom rocker cover.
If equipped with Jake Brakes remove the Jake Brake assembly.
7. Remove all the rocker shaft mounting bolts and nut from the front or rear rocker shaft assembly. Using rocker arm lifter (J–35996–A), see Figure 3-1, lift the assembly straight up and off of the head and place in a clean area on the bench.
8.Use tool J-47808 to remove the 4–pin electrical connection from the injector.
9. Disengage the locking tang on the harness plug connection, grasp the connector and gently pull it from the socket.
10. Remove the injector hold down clamps.
11.Remove the three injectors to be tested from the cylinder head.
12. Place the compression test adaptors (J-47373) into the injector holes. It is recommended
to have three test adaptors (J-47373) when performing this routine.
13. Install the injector hold down clamps and torque hold down bolts to 58-66 N·m (43-49 lb·ft).
14. Carefully remove the shaft from the rocker arm assembly by slowly pulling it out of the assembly. Place the shaft on the bench. Do not disturb the stack-up of the rocker arm sets.
15. Remove the three injector rocker arms and replace with spacers (J–38768–5) .
16. Lubricate the shaft with clean engine oil. With sleeves in place, carefully reinstall the shaft
through each rocker arm shaft. Make sure cup plug end faces inboard.
17. Install the modified rocker arm shaft assembly on the head. If the engine is equipped with a Jake Brake®, use non-Jake Brake rocker arm shaft bolts 8929129. Torque the three bolts and the nut to 102-108 N·m (75-80 lb·ft).
NOTE:
Verify that the bolt holes for the rocker shafts are clean as not to hydro lock the bolts
causing damage to the cylinder head.
18. Disconnect both connectors at the valve cover for the injectors.
NOTE:
Disconnect both connectors at the valve cover for the injectors.
19. Attach cylinder compression gauge (J–6692–B) to the first adaptor. See Figure 3-2.
20.Reconnect the batteries.
21. Crank the engine over using the starter motor 5 compression strokes record the compression reading on the gauge.
NOTE:
Verify that the batteries voltage does not go low enough to affect engine cranking speed.
If the cranking speed is affected then the results will be inaccurate. If needed connect a
battery charge to maintain battery voltage.
22.The compression reading should be 3102-3793 kPa (450-550 psi) with no two cylinders
differing by more than 276 kPa (40 psi). If compression readings are below specifications,
repeat step 20 to be certain of the reading.
23.After testing all three cylinders, remove bolts from the modified rocker arm shaft assembly and, using rocker arm lifter (J–35996), lift the assembly straight up and off the cylinder head. Place in a clean area on the bench.
24. Carefully remove the shaft from the rocker arm assembly, remove the three rocker arm sleeves. Replace the three injector rocker arms. Lubricate the shaft with clean engine oil and carefully reinstall through each rocker arm.
25. Remove the injector hold down clamps discard the hold down bolt and remove the compression test adaptors from the cylinder head.
26. Using new sealing rings and injector hold down bolt install the injectors back into the cylinder head and torque to specifications; Torque bolt to 50 Nm (37 lb ft) Loosen the bolt 60 degrees ( 1/6 of a turn or one bolt flat) Do not fully loosen the bolt. Torque the bolt to 35 Nm (26 lb ft) Tighten the bolt an additional 90 degrees.
27. Replace the completed rocker arm shaft assembly on the engine and torque nut and bolts to specifications torque to 102-108 N•m (75-80 lb•ft)
28. Repeat steps 4b-26 for the rear 3 cylinders
29. Install upper valve cover, insuring that the bolt hole are clear of dirt and oil as not to damage the lower rocker cover.
30. Check test results
