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MBE 4000 VALVES

The valves are controlled by mushroom tappets, pushrods, and rocker arms. The intake and exhaust valves are opened and closed by a valve-guided bridge. ‪

Valve Lift Checking

Check the valve lift as follows: ‪

Note: Do this procedure to determine, without removing the camshaft, if the camshaft, or parts of the valve train, have suffered excessive wear. If the camshaft itself is suspect, check the lift on every valve.

  1. Remove the cylinder head cover. Refer to section .
  2. Remove the inspection cover on the flywheel housing and install the engine cranking tool (J 46167 or 407 589 00 63 00) . Tighten the bolts on the cranking device 25 Nm (18 lbft).

    Note: Check cylinders one at a time.

  3. Select the first cylinder. Using the engine cranking tool (J 46167 or 407 589 00 63 00) , turn the flywheel until the piston in that cylinder is at ignition TDC (top dead center).
  4. Adjust the valve lash. See Figure 42059 . Refer to section .

    1. Rocker Arm ‪

    3. Valve Spring Retainer ‪

    2. Valve Bridge ‪

    Valve Lash and Valve Lift

  5. Check the valve lift on the intake valves. See Figure 42060 . Listed in Table are the specifications.

    1. Dial Gauge ‪

    4. Pushrod ‪

    2. Gauge Holder ‪

    5. Intake Valve ‪

    3. Intake Rocker Arm ‪

    Checking Valve Lift, Intake Valves

    Description

    Specification

    Specified Dial Gauge Preload for Checking Valve Lift ‪

    15 mm (0.60 in) ‪

    Valve Lift with Intake Valves Completely Open ‪

    11.546 mm (at least 0.4546 in) ‪

    Valve Lift with Exhaust Valves Completely Open ‪

    11.963 mm (at least 0.4710 in) ‪

    Inspection Cover Bolt Torque ‪

    25 Nm (18 lbft) ‪

    Valve Lift Specifications
    1. Mount a dial gauge and a gauge holder on the valve bridge. Mount the dial gauge with a preload of approximately 15 mm (0.60 inch) to provide adequate travel for checking the intake valve lift.
    2. Set the scale on the dial gauge to "0" (zero).
    3. Using the engine cranking tool (J 46167 or 407 589 00 63 00) , turn the flywheel in a counterclockwise direction (as viewed from the flywheel end).

      Note: The dial gauge will show the highest reading when the valve is completely open.

    4. When the valves are completely open, read off the value on the dial gauge. If the intake valve lift reaches at least 11.546 mm (0.4546 inch) at its highest point, the intake valves are lifting OK. Check the exhaust valves.

      If the intake valve lift fails to reach 11.546 mm (0.4546 inch) at its highest point, remove the camshaft and inspect the cams for wear. Refer to section . ‪

      Note: If the gauge reading fails to reach 11.546 mm (0.4546 inch), be sure the valves were completely open. The dial gauge will show the highest reading when the valve is completely open.

  6. Check the lift on the exhaust valves. See Figure 42061 .

    1. Dial Gauge ‪

    4. Pushrod ‪

    2. Gauge Holder ‪

    5. Exhaust Valve ‪

    3. Exhaust Rocker Arm ‪

    Checking Valve Lift, Exhaust Valves

    1. Turn the flywheel in a counterclockwise direction until both valves are closed.
    2. Move the dial gauge and gauge holder to the spring retainer on the exhaust valve. Make sure the dial gauge still has a preload of approximately 15 mm (0.60 inch) to provide adequate travel for checking the exhaust valve lift.
    3. Set the scale on the dial gauge to "0" (zero).
    4. Using the engine cranking tool, (J 46167 or 407 589 00 63 00) turn the flywheel in a counterclockwise direction (as viewed from the flywheel end).

      Note: The dial gauge will show the highest reading when the valve is completely open.

    5. When the valve is completely open, read off the value on the dial gauge. If the exhaust valve lift reaches at least 11.963 mm (0.4710 inch) at its highest point, the exhaust valve is lifting OK. Check the next cylinder.

      If the exhaust valve lift fails to reach 11.963 mm (0.4710 inch) at its highest point, remove the camshaft and inspect the cams for wear. Refer to section . ‪

      Note: If the gauge reading fails to reach 11.963 mm (0.4710 inch), be sure the valves were completely open. The dial gauge will show the highest reading when the valve is completely open.

  7. Check the valve lift, both intake and exhaust, on the remaining cylinders, one at a time, until all have been checked.
  8. Remove the dial gauge and holder from the cylinder head.
  9. Remove the engine cranking tool (J 46167 or 407 589 00 63 00) from the flywheel housing and install the inspection cover. Tighten the inspection cover bolts 25 Nm (18 lbft).
  10. Install the cylinder head cover. Refer to section .

Valve Lash Checking

Check and adjust the valve lash as follows: ‪

Note: Adjust the valve lash when the engine is cold. Wait at least 30 minutes after shutdown, even if the engine ran only a short time.

Select a method for adjusting the valves. There are two acceptable methods for adjusting the valves, prior to checking the valve lash: ‪

  • In order, according to the timing sequence used for fuel injection (see Method OneAdjust Each Cylinder in Firing Order);
  • By type of valve, depending on crankshaft position (see Method TwoAdjust All Valves Using Two Crankshaft Positions).
  • See Figure 42064 for the cylinder and valve layout on MBE 4000 engines. ‪

Cylinder and Valve Layout

Method One Adjust Each Cylinder in Firing Order

Method one allows you to adjust each cylinder in the order in which fuel is injected. The crankshaft must be repositioned after each cylinder is adjusted as listed in Table . ‪

Engine

Crankshaft Position

Cylinders

Cylinders

Cylinders

Cylinders

Cylinders

Cylinders

MBE 4000 ‪

Ignition TDC ‪

1 ‪

5 ‪

3 ‪

6 ‪

2 ‪

4 ‪

MBE 4000 ‪

Valve Overlap ‪

6 ‪

2 ‪

4 ‪

1 ‪

5 ‪

3 ‪

Valve Adjustment (Method One)

Note: Clean each cylinder head cover before removing it.

  1. Remove the cylinder head covers. See Figure 42062 . Refer to section .

    1. Socket-Head Bolt ‪

    3. Gasket ‪

    2. Cylinder Head Cover ‪

    4. Cylinder Head ‪

    Cylinder Head Cover, (exploded view)

  2. Remove the inspection cover on the flywheel housing.
  3. Fit the engine cranking tool (J 46167 or 407 589 00 63 00) into the inspection hole on the flywheel housing. See Figure 42063 .

    1. Inspection Cover ‪

    2. Cranking Device ‪

    Placement of the Cranking Tool

  4. For each cylinder, use the cranking tool to turn over the crankshaft until the piston is exactly at top dead center (TDC) in the compression stroke. The valves must be closed and it must be possible to turn the pushrods without effort.

    Note: When the piston in cylinder #1 is at ignition TDC, the valves of cylinder #6 will overlap, meaning that both intake and exhaust valves are partially open, and show no measurable play when tested with a feeler gauge.

  5. Check each valve and adjust it (if necessary), using the procedures under the headings "Checking Valve Lash" and "Adjusting Valve Lash."
  6. For each valve, measure the valve lash with a feeler gauge between the rocker arm and valve bridge. It should be possible to pull the feeler gauge through with no more than light resistance.
  7. If the value measured is within the range given in the "Check For" column listed in Table , check the next valve.

    Valve Type

    Check For: mm (inches)

    Adjust to: mm (inches)

    Intake ‪

    0.30 to 0.60 (0.012 to 0.024) ‪

    0.40 (0.016) ‪

    Exhaust ‪

    0.50 to 0.80 (0.020 to 0.032) ‪

    0.60 (0.024) ‪

    Valve Lash Checking and Adjustment
  8. If the value measured is outside the range given in the "Check For" column listed in Table , adjust the valve lash. ‪

Method Two Adjust All Valves Using Two Crankshaft Positions

Method two allows you to adjust all the valves using just two crankshaft positions. ‪

Note: Clean each cylinder head cover before removing it.

  1. Remove the cylinder head covers. See Figure 42062 . Refer to section .

    1. Socket-Head Bolt ‪

    3. Gasket ‪

    2. Cylinder Head Cover ‪

    4. Cylinder Head ‪

    Cylinder Head Cover, (exploded view)

  2. Remove the inspection cover on the flywheel housing.
  3. Fit the engine cranking tool (J 46167 or 407 589 00 63 00) into the inspection hole on the flywheel housing. See Figure 42063 .

    1. Inspection Cover ‪

    2. Cranking Device ‪

    Placement of the Cranking Tool

  4. Using the cranking tool, turn the crankshaft until cylinder #1 is at the ignition TDC position (all valves are closed) and cylinder #6 is at the valve overlap position (all valves are open).

    Note: When the piston in cylinder #1 or #6 is at ignition TDC, there will be a small bevelled alignment mark visible through the inspection hole. See Figure 42065 .

    Flywheel Alignment Mark

  5. Check the valves in the "Ignition TDC" row listed in Table , and adjust them (if necessary), using the procedures under the headings "Checking Valve Lash" and "Adjusting Valve Lash."

    Engine

    Cylinder #1 Crankshaft Position

    Cylinder Valves/Types*

    Cylinder Valves/Types*

    Cylinder Valves/Types*

    Cylinder Valves/Types*

    Cylinder Valves/Types*

    Cylinder Valves/Types*

    1 ‪

    2 ‪

    3 ‪

    4 ‪

    5 ‪

    6 ‪

    MBE 4000 ‪

    Ignition TDC ‪

    I/E ‪

    I ‪

    E ‪

    I ‪

    E ‪

    MBE 4000 ‪

    Valve Overlap ‪

    E ‪

    I ‪

    E ‪

    I ‪

    I/E ‪

    Valve Adjustment (Method Two)

  6. Using the cranking tool, turn the crankshaft until cylinder #6 is at the ignition TDC position (all valves are closed) and cylinder #1 is at the valve overlap position (all valves are open).
  7. Using the same procedure, check the valves in the "Valve Overlap" row listed in Table and adjust them (if necessary), using the procedures under the headings "Checking Valve Lash" and "Adjusting Valve Lash."
  8. For each valve, measure the valve lash with a feeler gauge between the rocker arm and valve bridge. It should be possible to pull the feeler gauge through with no more than light resistance.
  9. If the value measured is within the range listed in Table in the "Check For" column, check the next valve.

    Valve Type

    Check For: mm (inches)

    Adjust to: mm (inches)

    Intake ‪

    0.30 to 0.60 (0.012 to 0.024) ‪

    0.40 (0.016) ‪

    Exhaust ‪

    0.50 to 0.80 (0.020 to 0.032) ‪

    0.60 (0.024) ‪

    Valve Lash Checking and Adjustment
  10. If the value measured is outside the range given in the "Check For" column listed in Table , adjust the valve lash. ‪

Valve Lash Adjusting

Adjust the valve lash as follows: ‪

  1. If adjustment is needed, unscrew the locknut. See Figure 42066 . Turn the adjusting screw until the valve lash is correct. Use the exact settings given in the "Adjust To" column listed in Table .

    1. Adjusting Screw ‪

    2. Locknut ‪

    Valve Lash Adjustment

    Note: When adjusting the valves, adjust to the exact setting. Use the range only for checking adjustment.

  2. Tighten the locknut 50 Nm (37 lbft).
  3. Check the valve lash again. Adjust again if necessary.
  4. Install the cylinder head covers. Refer to section .
  5. Remove the cranking tool from the inspection hole in the flywheel housing.
  6. Replace the end cover on the inspection hole and tighten the bolts 25 Nm (18 lbft).

Measuring Valve Standback

Measure the valve standback as follows: ‪

  1. Remove the cylinder head from the engine. Refer to section .
  2. Set up a dial gauge and dial gauge holder with a preload on the lower contact surface of the cylinder head. See Figure 42075 .

    1. Lower Contact Surface of Cylinder Head ‪

    3. Dial Gauge ‪

    2. Valve Head ‪

    4. Dial Gauge Holder ‪

    Setting the Dial Gauge Preload

    Note: Before doing this procedure, make sure the valve head is making contact with the valve seat.

  3. Measure the valve standback listed in Table , from the cylinder head. See Figure 42076 .

    Note: The valve standback is the difference in height between the lower contact surface of the cylinder head and the valve head, when it is touching the valve seat.

    1. Cylinder Head ‪

    3. Valve Stem ‪

    2. Valve Head ‪

    Measuring Valve Standback

    Valve Type

    Description

    mm (inch)

    Intake ‪

    Normal ‪

    0.7-1.1 (0.03-0.04) ‪

    Intake ‪

    Wear Limit ‪

    1.6 (0.06) ‪

    Exhaust ‪

    Normal ‪

    0.7-1.1 (0.03-0.04) ‪

    Exhaust ‪

    Wear Limit ‪

    1.6 (0.06) ‪

    Valve Standback
    1. Set the scale of the dial gauge to "0" (zero).
    2. Move the dial gauge enough so that its probe is touching the valve head.
    3. If the gauge reads between 0.7 and 1.1 mm (0.03 and 0.04 inch), the valve standback is within specifications for new cylinder heads. Skip down to "Install the cylinder head..."

      If the gauge reads less than 0.7 mm (0.03 inch), or more than 1.1 mm (0.04 inch), the valve standback is not within specifications. ‪

    4. For used heads, if the gauge reads more than 1.6 mm (0.06 in.), inspect valve and valve seats.Listed in Table are the specifications.
  4. Install the cylinder head. Refer to section .

Valve Removal

Remove the intake and exhaust valves as follows: ‪

Note: The MBE 4000 engine has individual heads for each cylinder. To replace the valves on one head, follow these instructions, step by step. To replace all the valves, repeat these instructions for all six cylinder heads.

  1. Remove the cylinder head from the engine. Refer to section .
  2. Using a dial gauge and holder, measure the valve standback from the cylinder head. Refer to section . Listed in Table are the normal tolerances and wear limits.

    Valve Type

    Description

    mm (inch)

    Intake ‪

    Normal ‪

    0.7-1.1 (0.03-0.04) ‪

    Intake ‪

    Wear Limit ‪

    1.6 (0.06) ‪

    Exhaust ‪

    Normal ‪

    0.7-1.1 (0.03-0.04) ‪

    Exhaust ‪

    Wear Limit ‪

    1.6 (0.06) ‪

    Valve Standback

    Note: If the measurement is not within tolerance, machine the valve seat insert, using the procedures . If the measurement is beyond the wear limit, replace the valve seat insert.

  3. Place the cylinder head on wooden blocks.
  4. Attach the valve spring adaptor and remover, (J 46173) , to the cylinder head. See Figure 42067 .

    1. Valve ‪

    2. Cylinder Head ‪

    Valve Removal

  5. Using the adaptor/remover tool (J 46173) , press down on the valve spring retainer. Remove the collets with a magnetic pin. See Figure 42068 .

    1. Collet ‪

    5. Exhaust Valve ‪

    2. Spring Retainer ‪

    6. Intake Valve ‪

    3. Valve Spring ‪

    7. Cylinder Head ‪

    4. Spacer Washer ‪

    Valves (exploded view)

  6. Relieve the pressure on the adaptor/remover. Remove the valve spring retainers, valve springs, and spacer washers.
  7. Turn over the cylinder head and remove the valves.

    Note: Mark the valves in order for ease of installation.

  8. With the cylinder head again in the upright position, remove and discard the valve stem seals. See Figure 42069 .

    1. Valve Stem Seal ‪

    3. Cylinder Head ‪

    2. Valve Guide ‪

    Valve Stem Seals

  9. Inspect the valve guides for wear. See Figure 42070 . Listed in Table are the specifications.

    1. Valve Guide ‪

    2. Cylinder Head ‪

    Measuring the Inside Diameter of the Valve Guide

    Description

    mm (inch)

    Normal ‪

    9.000-9.022 (0.3543-0.3552) ‪

    Wear Limit ‪

    9.050 (0.3563) ‪

    Inside Diameter of Valve Guide
    1. Measure the inside diameter of the valve guide by inserting the go/no go gauge (J 46181 or 636 589 00 21 00) into the valve guide.
    2. Replace the valve guide if the larger diameter end of the go/no go gauge tool (J 46181 or 636 589 00 21 00) fits into either end of the guide.
  10. Clean the valves thoroughly. Remove any traces of combustion residue.
  11. Check the valves to see if they can be re-used. Replace the valves if the stem ends are damaged or bent, if the valve grooves are deformed, if the seat is burned, or if the chrome surface of the shaft is not entirely intact.
  12. Check the following critical valve dimensions, and repair as necessary. See Figure 42071 to determine the dimensions given in the table. Listed in Table are the dimensions.
    • Valve stem diameter (A)
    • Valve seat diameter at the contact surface of the cylinder head (B)
    • Valve head diameter (C)
    • Valve seat height (D)
    • Valve seat width at the valve head (E)
    • Valve seat angle (F)
    • Valve length (G)
    • Critical Dimensions, Valve Stem and Head

      Description

      Intake

      Exhaust

      Valve Stem Diameter (A) ‪

      8.935-8.950 (0.3518-0.3524) ‪

      8.925-8.940 (0.3514-0.3520) ‪

      Valve Seat Diameter, at Head Contact Surface (B) ‪

      42.0 (1.65) ‪

      39.0 (1.54) ‪

      Valve Head Diameter (C) ‪

      45.4-45.6 (1.79-1.80) ‪

      40.9-41.3 (1.61-1.63) ‪

      Valve Seat Height-New (D) ‪

      3.1-3.3 (0.12-0.13) ‪

      2.8-3.1 (0.11-0.12) ‪

      Minimum Valve Seat Height-After Grinding (D) ‪

      2.9 (0.11) ‪

      2.3 (0.09) ‪

      Valve Seat Width, at Valve Head (E) ‪

      3.5-4.5 (0.14-0.18) ‪

      3.5-4.5 (0.14-0.18) ‪

      Valve Seat Angle (F) ‪

      30 degrees ‪

      45 degrees ‪

      Valve Length (G) ‪

      145.0 (5.71) ‪

      145.0 (5.71) ‪

      Valve Removal/Installation Specifications in mm (inches)
  13. Check the condition of the valve seat insert. Repair the valves if necessary.
  14. Inspect the valve springs. Check the springs for correct pressure, using the values listed in Table . If damaged, replace the springs.

    Description

    mm (inches)

    Length, Without Load ‪

    69.7 (2.74) ‪

    Length, Under Load of 382-418 N (86-94 lbf) ‪

    49 (1.9) ‪

    Length, Under Load of 644-706 N (145-159 lbf) ‪

    37 (1.5) ‪

    Diameter of Spring Wire ‪

    4.2 (0.17) ‪

    Outside Diameter of Spring Coil ‪

    28.9 (1.14) ‪

    Inside Diameter of Spring Coil ‪

    24.5-24.9 (0.96-0.98) ‪

    Spring Specifications, Intake and Exhaust Valves

Valve Installation

Install the intake and exhaust valves as follows: ‪

  1. Lubricate each valve with a light coating of engine oil.
  2. Install the valves in order, as marked on removal.

    Note: Always replace the valve stem seal if the valve has been removed. Check the seal to make sure it is correctly seated on the valve guide. Refer to section .

  3. Install new valve stem seals. Refer to section .
  4. Using the adaptor/remover, (J 46173) , install the spring bases, springs, spring retainers, and collets. Check the collets to be sure they are locked in place.
  5. Remove the adaptor/remover, (J 46173) , from the cylinder head.
  6. Install the cylinder head. Refer to section .

Valve Stem Seal Replacement

Replace the valve stem seal as follows: ‪

Note: Always replace the valve stem seal if the valve has been removed.

  1. Remove the cylinder head from the engine. Refer to section .

    Note: Use care during removal to not damage the valve guides and valve stems.

  2. Remove the collets, spring retainer, valve spring, and spring base. See Figure 42074 .

    1. Valve Stem Seal ‪

    3. Valve Guide ‪

    2. Valve Stem ‪

    Valve Stem Seal Replacement

  3. Remove the valve stem seal. Do not remove the valve.
  4. Lubricate the valve stem and valve stem seal installer (J 46184 or 403 589 00 61 00) with a light coating of clean engine oil.

    Note: The installer prevents the groove on the valve stem from damaging the seal.

  5. Push the valve stem seal installer (J 46184 or 403 589 00 61 00) over the valve stem until it makes contact with the valve.
  6. Slide the seal over the installer and the valve stem. Using fingers, press the seal into place until the seal seats on the valve guide.

    Note: Check the seal to make sure it is correctly seated on the valve guide.

  7. Remove the installer from the valve stem seal and the valve.
  8. Install the collets, spring retainer, valve spring and spring base, as removed.
  9. Repeat the procedure for the other valves.
  10. Install the cylinder head. Refer to section .