MBE 4000 – Section 1.23 Camshaft and Camshaft Position Sensor

Section 1.23
Camshaft and Camshaft Position Sensor

The camshaft is made of induction-hardened steel and has seven main bearings. Each cylinder has cams for intake and exhaust valves and a unit pump.‪

Section 1.23.1
Camshaft Removal

Remove the camshaft as follows:‪

Note: Before removing the camshaft, clean the engine to prevent road dirt, grease, or other foreign matter from contaminating the exposed gears and other engine parts.

1. Drain the engine oil.

   FALLING ENGINE ‪
   To avoid injury from a falling engine, an adequate lifting device with a spreader bar and sling should be used to lift the engine. The sling and spreader bar should be adjusted so the lifting hooks are vertical to prevent bending the lifter brackets. To ensure proper weight distribution, all provided lifter brackets must be used.‪

   NOTICE:
   A spreader bar must be used at all times in conjunction with the front and rear lifter brackets to lift the EGR engine to ensure that no engine damage will result. The brackets are designed to lift vertically. ‪

2. Remove the engine from the vehicle.

   FALLING ENGINE ‪
   To avoid injury from a falling engine, ensure the engine is securely attached to the engine overhaul stand before releasing the lifting sling.‪

3. Install the engine on an engine stand.
4. Remove the electronic unit pumps (EUP).
5. Remove the vibration damper. Refer to "1.12.1 Crankshaft Vibration Damper Removal" .
6. Remove the fan support.
7. Remove the eight mounting bolts attaching the camshaft front cover to the cylinder block. See Figure "Removing the Camshaft Front Cover" .
   

   Figure 1. Removing the Camshaft Front Cover

8. Remove the fuel pump drive gear from the front of the camshaft. See Figure "Camshaft Assembly" .
   

   1. Drive Gear Mounting Bolt‪	3. Cover Mounting Bolt‪	5. Front of Camshaft‪
   2. Front Camshaft Cover‪	4. Fuel Pump Drive Gear‪	6. Fuel Pump Driven Gear‪

   Figure 2. Camshaft Assembly

9. Remove the rocker arm assembly and pushrods. Refer to "1.22.1 Rocker Arm Removal" .
10. Turn the engine on the stand until it is upside down.
11. Remove the oil pan.
12. Remove the flywheel housing. Refer to "1.17.1 Flywheel Housing Removal" .

    NOTICE:
    Do not damage the camshaft bearings in the crankcase. If the camshaft bearings are damaged, the crankcase will have to be replaced.‪

13. Attach the camshaft guide tool (J-46183) to the front of the camshaft. See Figure "Attaching the Camshaft Guide Tool" .
    

    1. Front of Camshaft‪

    Figure 3. Attaching the Camshaft Guide Tool

14. From the gear end (rear of the engine), carefully remove the camshaft from the block. See Figure "Attaching the Camshaft Guide Tool" .
15. Pull the tappets (valve lifters) out of the block. Mark the tappets, in order, as removed. See Figure "Removing the Tappets" .
    

    1. Cylinder Block‪	3. Tappet (valve lifter)‪
    2. Camshaft Entry Hole‪	4. Fuel Pump Driven Gear‪

    Figure 4. Removing the Tappets

16. Clean and inspect the tappets. Replace the tappets if there are signs of damage or wear, or if any of the measurements do not meet the specifications listed in Table "Valve Tappet Specifications" .

    Description ‪	Repair Stage ‪	Specifications: mm (in.) ‪
    Tappet Outside Diameter‪	Standard‪	29.931-29.952 (1.1784-1.1792)‪
    Tappet Outside Diameter‪	Repair Stage I‪	30.444-30.465 (1.1986-1.1994)‪
    Tappet Housing Diameter (in cylinder block)‪	Standard‪	30.000-30.021 (1.1811-1.1819)‪
    Tappet Housing Diameter (in cylinder block)‪	Repair Stage I‪	30.500-30.525 (1.2008-1.2018)‪

    Table 8. Valve Tappet Specifications
    1. Measure the outside diameter of each tappet.
    2. Measure the diameter of the tappet housing in the cylinder block.
17. Inspect the camshaft. Refer to "1.23.1.1 Camshaft Inspection" .

Section 1.23.1.1
Camshaft Inspection

Inspect the camshaft as follows:‪

Note: To get a correct hardness reading, it is critical to place a hard base below the cam or bearing journal.

1. Using a hardness tester, inspect the hardness of the cams and bearing journals at the camshaft. A hard base should be placed below the cam or bearing journal to be inspected. See Figure "Inspecting Cam Hardness" .
   

   1. Camshaft‪

   2. Hardness Tester‪

   Figure 5. Inspecting Cam Hardness

2. Measure the diameter of each bearing journal. Measure the diameter of the bushing at each journal. See Figure "Measuring the Cam Rise" .
   

   1. Camshaft Gear‪

   2. Dial Gauge‪

   Figure 6. Measuring the Cam Rise

3. Mount the camshaft at the outer journals.

   Note: For all of the following steps, use a dial gauge.

4. Measure the radial runout of the cam basic circle.
5. Measure the cam rise of the intake valve cams. See Figure "Measuring the Cam Rise" , Ref. I.
6. Measure the cam rise of the exhaust valve cams. See Figure "Measuring the Cam Rise" , Ref. E.
7. Measure the cam rise of the unit pump valve cams. See Figure "Measuring the Cam Rise" , Ref. U.
8. Replace the camshaft if any of the measurements do not meet the specifications listed in Table "Camshaft Specifications" .

   What To Measure ‪	Where To Measure ‪	Value: mm (in.) Unless otherwise noted ‪
   Hardness of Surface‪	At Cams and Journals‪	57–63 HRC‪
   Camshaft Radial Runout When Mounted on Outer Bearing Journals‪	At Gear Seat‪	0.020 (0.0008)‪
   Camshaft Radial Runout When Mounted on Outer Bearing Journals‪	At Cam Circle‪	0.025 (0.0010)‪
   Camshaft Radial Runout When Mounted on Outer Bearing Journals‪	At Camshaft Journals‪	0.030 (0.0012)‪
   Minimum Valve Cam Rise–Above Basic Circle‪	Intake Valve‪	7.3 (0.29)‪
   Minimum Valve Cam Rise–Above Basic Circle‪	Exhaust Valve‪	8.2 (0.32)‪
   Camshaft Journal Diameter‪	For New Camshaft‪	81.893–81.928 (3.2241–3.2255)‪
   Bushing Diameter‪	At Camshaft Journals‪	82.000–82.035 (3.2283–3.2297)‪
   Gear Back Lash‪	Cam Gear to Crank Gear‪	0.074–0.176 (0.0029–0.0069)‪
   Gear Back Lash‪	Cam Gear to Air Compressor Gear‪	0.082–0.168 (0.0032–0.0066)‪

   Table 11. Camshaft Specifications

Section 1.23.2
Camshaft Installation

Install the camshaft as follows:‪

1. Lubricate the tappets with a light coating of clean engine oil.
2. Install the tappets in the block, in order, as removed.

   NOTICE:
   Do not damage the camshaft bearings in the crankcase. If the camshaft bearings are damaged, the crankcase will have to be replaced.‪

3. Install the camshaft.
   1. Lubricate the cams and camshaft journals with a light coating of clean engine oil.
   2. Attach the camshaft guide tool (J-46183) to the camshaft.
   3. Rotate the camshaft until the marked gear teeth on the camshaft gear are aligned with the marked tooth on the crankshaft gear. See Figure "Aligning the Marked Gear Teeth" .
   

   1. Camshaft Gear‪

   2. Crankshaft Gear‪

   3. Dowel Pin ‪

   Figure 7. Aligning the Marked Gear Teeth

   4. Carefully insert the camshaft into the block.
4. Install the flywheel housing. Refer to "1.17.2 Flywheel Housing Installation" .
5. Install the oil pan.
6. Install the fuel pump drive gear on the front of the camshaft, as removed. Torque the bolts to 60 N·m (44 lb·ft.)
7. Turn the engine on the stand until it is right side up.
8. Install the unit pumps.
9. Install the camshaft front cover on the cylinder block, as removed. Torque the mounting bolts to 50 N·m (37 lb·ft.)
10. Install the fan support.
11. Install the vibration damper. Refer to "1.12.2 Crankshaft Vibration Damper Installation" .
12. Lubricate the pushrods with a light coating of clean engine oil. Install the pushrods and the rocker arm assembly. Refer to "1.22.4 Rocker Arm Installation" .

    FALLING ENGINE ‪
    To avoid injury from a falling engine, an adequate lifting device with a spreader bar and sling should be used to lift the engine. The sling and spreader bar should be adjusted so the lifting hooks are vertical to prevent bending the lifter brackets. To ensure proper weight distribution, all provided lifter brackets must be used.‪

    NOTICE:
    A spreader bar must be used at all times in conjunction with the front and rear lifter brackets to lift the EGR engine to ensure that no engine damage will result. The brackets are designed to lift vertically. ‪

13. Remove the engine from the stand and install it in the vehicle.
14. Fill the engine with oil.

Section 1.23.3
Camshaft Position Sensor Replacement

Replace the camshaft position (CMP) sensor as follows:‪

1. Disconnect the electrical connector at the CMP sensor. See Figure "Camshaft Sensor Installation" .
   

   1. Camshaft Position Sensor‪

   2. Crankshaft Position Sensor‪

   Figure 8. Camshaft Sensor Installation

2. Remove the sensor from the access hole in the flywheel housing by pulling the sensor outward.
3. Install a new sensor in the flywheel housing by pushing in the sensor into the access hole until it bottoms .
4. Connect the electrical connector to the CMP sensor.

Note: Be sure that the correct electrical connector is connected to the sensor.