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
for an exploded view of a cylinder head.
1. High Pressure Fuel Injector Line
8. Constant-Throttle Line
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
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.
Specifications for Measuring Cylinder Liner Protrusion
Inspect the cylinder head for cracks or signs of damage. Replace if necessary.
Cylinder Head Installation
Install the cylinder head as follows:
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.
Position the cylinder head on the head gasket. Make sure the head is seated onto the guide pins.
Head and gasket must be seated properly, or engine damage could result.
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
. 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
Shaft length when new
210.0 mm (8.27 inches)
Maximum shaft length
212.0 mm (8.35 inches)
Cylinder Head Bolt Lengths
Lubricate the cylinder head bolts with engine oil.
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.
Replace the seal rings and connect the fuel return line to the cylinder head.
Replace the seal rings and install the constant-throttle line on the cylinder head.
Connect the coolant line to the cylinder head.
Correct torque on the high-pressure lines is critical. Incorrect torques could result in leaks or lack of power due to restricted fuel flow.
Without moving the transfer tube thrust bolt, install the high-pressure injector line as removed.
When installing the transfer-tube fitting, use one wrench to hold the thrust bolt, and another to tighten the fitting.
Tighten the fitting 30 Nm (22 lbft).
Remove the wrench used to hold the location of the thrust bolt.
Install new exhaust manifold gaskets on all exhaust ports. Make sure the gaskets are all positioned correctly.
Install new manifold gaskets on all exhaust ports, regardless of how many heads were removed.
Install the exhaust manifold and tighten the bolts 50 Nm (37 lbft).
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.
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.
Minimum Oil Pressure Reading
Engine at Idle Speed
50 kPa (7 psi)
Engine at Max. rpm
250 kPa (36 psi)
Oil Pressure Readings
Stop the engine, check the coolant level, and top off if necessary.
Inspect the contact surface (bottom face) of the cylinder head for warpage, both lengthwise and diagonally. See Figure
. If the gap is larger than 0.015 mm (0.0006 inch), machine the cylinder head.
1. Contact Surface
Measuring Cylinder Head Warpage
Place a straightedge lengthwise across the cylinder head contact surface (bottom face).
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.
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
Maximum Permissible Warpage of Head Mating Surface
Lengthwise and Diagonally
Maximum Permissible Parallelism Deviation of Head Mating Surface
At Each of the Four Corners
Overall Height of Cylinder Head
Cylinder Head Specifications
Place the straightedge diagonally across the cylinder head. Repeat the procedure above.
Check the cylinder head contact surface for parallelism, at each corner. See Figure
. If the four measurements deviate by more than 0.1 mm (0.004 inch), machine the cylinder head.
Measuring Cylinder Head Parallelism
Rest the cylinder head on a flat surface, with the contact surface exposed (bottom face up).
Make sure the head is level before going on with this check.
Install a dial gauge so that the feeler touches the contact surface with some preload.
Fasten the dial gauge and adjust the scale to "0" (zero).
Check the reading on the dial gauge. If the reading is larger than 0.1 mm (0.004 inch), machine the cylinder head.
Repeat this procedure at each spot marked by an arrow (each corner of the cylinder head).
Measure the overall height of the cylinder head. See Figure
. 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
Machine the contact surface of the cylinder head, to correct any problems found during inspection.
If rejected for warpage, check warpage again until it is within specifications.
If rejected for lack of parallelism, check parallelism again until it is within specifications.
After machining, check again the overall height of the cylinder head.
Make sure the smooth surface on the O-ring is pointing toward the test adaptor.
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.
Tighten the bolt attaching the hold-down to the cylinder head.
Follow the equipment manufacturer's operating instructions to connect the compression tester.
Remove the electrical connectors from all unit pumps. When this is done, the engine will not start.
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.
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
Pressure in kPa (psi)
Minimum Compression Pressure Valve
Permissible Difference Between Individual Cylinders
Connect all unit pumps, as removed.
Connect minidiag2 to the vehicle and clear all inactive faults.
Follow the equipment manufacturer's operating instructions.