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MBE 4000 CYLINDER HEAD

The MBE 4000 engine has individual heads for each cylinder. To remove one head, follow these instructions, step by step. To remove all the heads, repeat each step in these instructions, as applicable, for all six cylinders. ‪

Cylinder Head Removal

Remove the cylinder head as follows: See Figure 41872 for an exploded view of a cylinder head. ‪

1. High Pressure Fuel Injector Line ‪

8. Constant-Throttle Line ‪

2. Pushrod ‪

9. Spacer ‪

3. Cylinder Head ‪

10. Exhaust Port Gasket ‪

4. Seal Ring ‪

11. Cylinder Head Gasket ‪

5. Hollow Core (Banjo) Bolt ‪

12. Exhaust Manifold ‪

6. Fuel Return Line ‪

13. Exhaust Manifold Mounting Bolt ‪

7. Cylinder Head Bolt ‪

14. Guide Pin ‪

Exploded View of Cylinder Head

HOT COOLANT

To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.

  1. Drain the coolant from the radiator. Refer to section .

    Note: Clean the cylinder head cover before removing it.

  2. Remove the cylinder head cover. Refer to section .
  3. Remove the rocker arm assembly. Mark the valve bridges and pushrods in order of removal. Refer to section .
  4. Remove the engine trim cover to gain access to the fuel injector lines.
  5. Remove the charge-air intake manifold. Refer to section .

    NOTICE:

    Do not move the thrust bolt, because there is danger of causing a change in the position of the transfer tube. If the position of the transfer tube is changed, engine damage could result.

  6. Using two wrenches, loosen the high-pressure injector line fittings. See Figure 41871 .

    1. Pump-End Fitting ‪

    3. Transfer-Tube Fitting ‪

    2. High-Pressure Injector Line ‪

    4. Thrust Bolt ‪

    High-Pressure Line Fittings

    1. Using a paint pen, mark the location of the thrust bolt.
    2. Place one wrench on the thrust bolt to secure the transfer tube. Place the other wrench on the high-pressure line fitting.
    3. Turn the wrench on the high-pressure line fitting while holding the other wrench on the thrust bolt.
  7. Remove the high-pressure injector line from the head and unit pump.
  8. To prevent any dirt from entering, cover the openings in the unit pump and the transfer tube.
  9. Remove the exhaust manifold bolts.

    Note: If removing one or two cylinder heads, loosen the bolts on the rest of the exhaust manifold.

  10. Pull the exhaust manifold away from the engine, towards the frame rail. Remove all the gaskets.

    Note: If removing all cylinder heads, remove the exhaust manifold from the engine.

  11. Remove the fuel return line from the cylinder head. Discard the seal rings.
  12. Disconnect the constant-throttle line from the cylinder head. Discard the seal rings.
  13. Disconnect the coolant line from the cylinder head.
  14. Using the head bolt impact socket (J 45389 or 422 589 00 09 00) , loosen the cylinder head bolts. When all the bolts are loose, remove the bolts from the cylinder head. See Figure 41873 .

    Loosening the Head Bolts

    NOTICE:

    Do not place the head mating surface down on a flat surface. This would damage the injector nozzles, which protrude slightly.

  15. Remove the cylinder head and set it on wooden blocks or on its side.
  16. Remove the head gasket.
  17. Thoroughly clean the cylinder head, both contact surfaces (head and block), and surfaces inside the cylinder of excess oil, grime, and paint chips.
  18. With a straightedge, check the cylinder head surface for warpage. Refer to section . Listed in Table are warpage limits.

    Description

    Limit

    Over a length of 150 mm (6 in.) ‪

    0.015 mm (0.0006 in.) ‪

    Head Warpage Limits
  19. Check the cylinder liner protrusion from the cylinder block. Listed in Table are the specifications. Refer to section .

    Description

    Value: mm (in.)

    Cylinder Liner Protrusion from block ‪

    0.230-0.330 mm (0.0090-0.0130 in.) ‪

    Difference between the four measuring points ‪

    Max.: 0.02 mm (0.0007 in.) ‪

    Specifications for Measuring Cylinder Liner Protrusion
  20. Inspect the cylinder head for cracks or signs of damage. Replace if necessary.

Cylinder Head Installation

Install the cylinder head as follows: ‪

  1. Install a new head gasket. Match up the holes in gasket with those in the cylinder block and place the head gasket over the guide pins in the block.
  2. Position the cylinder head on the head gasket. Make sure the head is seated onto the guide pins.

    NOTICE:

    Head and gasket must be seated properly, or engine damage could result.

  3. Using a dial caliper, measure the length of the cylinder head bolts from the end of the bolt to the bottom of the flange. See Figure 41874 . Listed in Table are the acceptable lengths. Replace any bolts which do not meet these specifications.

    1. Dial Caliper ‪

    3. Bottom of Flange ‪

    2. End of Cylinder Head Bolt ‪

    Measuring Head Bolts

    Description

    Length

    Shaft length when new ‪

    210.0 mm (8.27 inches) ‪

    Maximum shaft length ‪

    212.0 mm (8.35 inches) ‪

    Cylinder Head Bolt Lengths
  4. Lubricate the cylinder head bolts with engine oil.
  5. Using the head bolt impact socket (J 45389 or 422 589 00 09 00) , install the cylinder head bolts.

    Note: For the correct tightening sequence, see Figure 41875 . Listed in Table are the specific stages in the tightening sequence.

    Tightening Sequence, Cylinder Head Bolts

    Size

    Max. Shaft Length

    Tightening Stage

    Torque Value (Repair work in the field)

    M15 x 2 ‪

    212.0 mm (8.35 in.) ‪

    Stage 1 ‪

    10 Nm (7 lbft) ‪

    Stage 2 ‪

    50 Nm (37 lbft) ‪

    Stage 3 ‪

    100 Nm (74 lbft) ‪

    Stage 4 ‪

    200 Nm (148 lbft) ‪

    Stage 5 ‪

    90 more ‪

    Stage 6 ‪

    90 more ‪

    Tightening Stages, Cylinder Head Bolts

    Note: If the stretch bolt tightening torque is exceeded, remove it, check its maximum permissible shaft length (replace if necessary), and tighten it from Stage 1. Unconditionally replace all bolts whose shaft length exceeds the maximum permissible value.

  6. Replace the seal rings and connect the fuel return line to the cylinder head.
  7. Replace the seal rings and install the constant-throttle line on the cylinder head.
  8. Connect the coolant line to the cylinder head.

    NOTICE:

    Correct torque on the high-pressure lines is critical. Incorrect torques could result in leaks or lack of power due to restricted fuel flow.

  9. Without moving the transfer tube thrust bolt, install the high-pressure injector line as removed.
    1. When installing the transfer-tube fitting, use one wrench to hold the thrust bolt, and another to tighten the fitting.
    2. Tighten the fitting 30 Nm (22 lbft).
    3. Remove the wrench used to hold the location of the thrust bolt.
  10. Install new exhaust manifold gaskets on all exhaust ports. Make sure the gaskets are all positioned correctly.

    Note: Install new manifold gaskets on all exhaust ports, regardless of how many heads were removed.

  11. Install the exhaust manifold and tighten the bolts 50 Nm (37 lbft).
  12. Install the charge-air intake manifold. Refer to section .
  13. Lubricate the pushrods with a light coating of engine oil and install the pushrods, in order, as removed.

    Note: Make sure the pushrods are correctly seated in the valve tappets.

  14. Install the valve bridges, in order, as removed.
  15. Install the rocker arm assembly, in order, as removed. Tighten each rocker arm mounting bolt first 60 Nm (44 lbft); then an additional 90. Refer to section .
  16. Install the cranking tool and adjust the valves. For valve lash adjustment procedures, refer to section .
  17. Remove the cranking tool. Refer to section .
  18. Install the inspection hole end cover on the flywheel housing. Tighten the fasteners 25 Nm (18 lbft).
  19. Check that the coolant drain plug is tight and not leaking.
  20. Fill the radiator with coolant. Refer to section .
  21. Install the cylinder head cover. Refer to section .
  22. Install the engine trim cover.

    Note: Prime the fuel system. Refer to section .

    PERSONAL INJURY

    Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.

    • Always start and operate an engine in a well ventilated area.
    • If operating an engine in an enclosed area, vent the exhaust to the outside.
    • Do not modify or tamper with the exhaust system or emission control system.
  23. Turn on the ignition switch and test the engine. Observe the oil pressure gauge to verify the correct oil pressure. The maximum oil pressure readings at idle speed are listed in Table . Pay attention to the coolant temperature gauge, warning lights, fluid leaks, and any other signs of a problem.

    Description

    Minimum Oil Pressure Reading

    Engine at Idle Speed ‪

    50 kPa (7 psi) ‪

    Engine at Max. rpm ‪

    250 kPa (36 psi) ‪

    Oil Pressure Readings
  24. Stop the engine, check the coolant level, and top off if necessary.
Cylinder Head Inspection and Machining

Inspection

  1. Remove the cylinder head. Refer to section .
  2. Remove the nozzle holder. Refer to section .
  3. Remove the intake and exhaust valves. Refer to section .
  4. Remove the constant-throttle valve. Refer to section .
  5. Inspect the contact surface (bottom face) of the cylinder head for warpage, both lengthwise and diagonally. See Figure 41876 . If the gap is larger than 0.015 mm (0.0006 inch), machine the cylinder head.

    1. Contact Surface ‪

    2. Straightedge ‪

    Measuring Cylinder Head Warpage

    1. Place a straightedge lengthwise across the cylinder head contact surface (bottom face).
    2. If there is a gap between the lower edge of the straightedge and the contact surface of the cylinder head that is large enough to let light through, insert a feeler gauge into the gap.
    3. Measure the amount of warpage with the feeler gauge and compare it to the value listed in Table . If the gap is larger than 0.015 mm (0.0006 in.), machine the cylinder head.

      What To Measure

      How To Measure

      mm (inch)

      Maximum Permissible Warpage of Head Mating Surface ‪

      Lengthwise and Diagonally ‪

      0.015 (0.0006) ‪

      Maximum Permissible Parallelism Deviation of Head Mating Surface ‪

      At Each of the Four Corners ‪

      0.1 (0.004) ‪

      Overall Height of Cylinder Head ‪

      When New ‪

      113.85-114.15 (4.482-4.494) ‪

      After Machining ‪

      113.5 (4.46) ‪

      Cylinder Head Specifications
    4. Place the straightedge diagonally across the cylinder head. Repeat the procedure above.
  6. Check the cylinder head contact surface for parallelism, at each corner. See Figure 41877 . If the four measurements deviate by more than 0.1 mm (0.004 inch), machine the cylinder head.

    Measuring Cylinder Head Parallelism

    1. Rest the cylinder head on a flat surface, with the contact surface exposed (bottom face up).
    2. Note: Make sure the head is level before going on with this check.

    3. Install a dial gauge so that the feeler touches the contact surface with some preload.
    4. Fasten the dial gauge and adjust the scale to "0" (zero).
    5. Check the reading on the dial gauge. If the reading is larger than 0.1 mm (0.004 inch), machine the cylinder head.
    6. Repeat this procedure at each spot marked by an arrow (each corner of the cylinder head).
  7. Measure the overall height of the cylinder head. See Figure 41878 . Replace the head if below the minimum height. If above the maximum height, machine the head down to the maximum height listed in Table .

    1. Cylinder Head ‪

    3. Intake Valve ‪

    2. Exhaust Valve ‪

    Measuring Cylinder Head Height

Machining

  1. Machine the contact surface of the cylinder head, to correct any problems found during inspection.
    1. If rejected for warpage, check warpage again until it is within specifications.
    2. If rejected for lack of parallelism, check parallelism again until it is within specifications.
  2. After machining, check again the overall height of the cylinder head.
  3. Install the constant-throttle valve. Refer to section .
  4. Install the intake and exhaust valves. Refer to section .
  5. Install the nozzle holder. Refer to section .
  6. Install the cylinder head. Refer to section .
Engine Compression Testing

Perform the following steps to compression test the engine: ‪

Removal

Note: Start this procedure only when the engine is cold. Wait at least 30 minutes after switching off the engine.

  1. Set the parking brake and chock the tires.

    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.

  2. Remove the cylinder head cover. Refer to section .
  3. Adjust the valve lash. Refer to section .

    Note: To do this procedure, coolant temperature must be between 155 and 205F (70 to 95C).

    PERSONAL INJURY

    To avoid injury when working near or on an operating engine, remove loose items of clothing and jewelry. Tie back or contain long hair that could be caught in any moving part causing injury.

    PERSONAL INJURY

    Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.

    • Always start and operate an engine in a well ventilated area.
    • If operating an engine in an enclosed area, vent the exhaust to the outside.
    • Do not modify or tamper with the exhaust system or emission control system.
  4. Turn on the ignition keyswitch and run the engine until it reaches operating temperature.
  5. Shut down the engine.
  6. Remove the injector nozzle. See Figure 41868 . Refer to section .

    1. O-ring (transfer tube) ‪

    6. O-ring (nozzle) ‪

    2. Transfer Tube ‪

    7. Injector Nozzle ‪

    3. Thrust Bolt ‪

    8. Tensioning Arm ‪

    4. High-Pressure Fuel Line ‪

    9. Retaining Bolt ‪

    5. Seal Ring ‪

    10. Constant Throttle Valve Cover ‪

    Removing the Injector Nozzle

  7. Insert the compression test adaptor (J 45392 or 904 589 01 21 00) into the cylinder head. See Figure 41869 . Use the hold-down and bolt included in the kit.

    1. Button (on hold-down) ‪

    4. Constant Throttle Valve Cover ‪

    2. Bolt ‪

    3. Fitting ‪

    Installing the Test Adaptor

    1. Make sure the smooth surface on the O-ring is pointing toward the test adaptor.
    2. Install the hold-down with the two prongs around the test adaptor. Turn the hold-down (at the cylinder head) until the button in the base of the hold-down is aligned with the locating element in the end cover of the constant throttle.
    3. Tighten the bolt attaching the hold-down to the cylinder head.
    4. Note: Follow the equipment manufacturer's operating instructions to connect the compression tester.

  8. Attach the compression tester (J 6692B or 000 589 17 21 00) to the test adaptor (J 45392 or 904 589 01 21 00) . Snap the fitting at the end of the tester onto the top of the test adaptor. See Figure 41870 .

    1. Fitting ‪

    4. Constant Throttle Valve Cover ‪

    2. Bolt ‪

    3. Hold-Down ‪

    Testing Compression Pressure

Testing

  1. Remove the electrical connectors from all unit pumps. When this is done, the engine will not start.
  2. For each cylinder, use the starter to crank the engine at least 8 engine revolutions. The results will be recorded on the gauge of the tester.
  3. Compare measurements on the chart with the values listed in Table . If the pressure measured is below the minimum compression pressure or above the permissible difference, determine the cause and correct the problem. To remove the cylinder head, Refer to section .

    Description

    Pressure in kPa (psi)

    Minimum Compression Pressure Valve ‪

    2800 (406) ‪

    Permissible Difference Between Individual Cylinders ‪

    400 (58) ‪

    Compression Testing

Installation

  1. Connect all unit pumps, as removed.
  2. Connect minidiag2 to the vehicle and clear all inactive faults.

    Note: Follow the equipment manufacturer's operating instructions.

  3. Disconnect the compression tester gauge, (J 6692B or 000 589 17 21 00) from the test adaptor (J 45392 or 904 589 01 21 00) .
  4. Remove the compression test adaptor.
  5. Install the injector nozzle. Refer to section
  6. Install and tighten the tensioning arm.
    1. Position the tensioning arm on the nozzle and install the retaining bolt.
    2. Tighten the retaining bolt 50 Nm (37 lbft).
  7. Install the cylinder head cover. Refer to section .
  8. Repeat this procedure for each cylinder.
  9. Remove the chocks from the tires.