Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.
WARNING
Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.
WARNING
Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.
Disconnect the batteries or air supply to the air starter to prevent accidental engine starting.
Drain the cooling system. Refer to Procedure 008-018 in Section V.
Remove the air piping from the intake manifold and the turbocharger.
Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.
WARNING
Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.
WARNING
Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.
Disconnect the batteries or air supply to the air starter to prevent accidental engine starting.
Remove the oil supply line from the STC control valve to the STC oil manifold connection on the side of the rocker housing. Refer to Procedure 006-037 in Section 6.
Remove the three STC oil manifold mounting capscrews from inside the rocker lever housing.
This component or assembly weighs greater than 23 kg [50 lb]. To prevent serious personal injury, be sure to have assistance or use appropriate lifting equipment to lift this component or assembly.
Reference the L10 Alternative Repair Manual, Bulletin 3810310
Remove the seven 12-point cylinder head capscrews on the fuel pump side of the engine.
Remove the remaining 32 cylinder head capscrews in the sequence shown.
Three capscrews are located inside the intake ports.
Install cylinder head lifting bracket, Part Number 3822479, with two rocker lever support mounting capscrews and two of the long rocker housing mounting capscrews.
This component or assembly weighs greater than 23 kg [50 lb]. To prevent serious personal injury, be sure to have assistance or use appropriate lifting equipment to lift this component or assembly.
CAUTION
Place the cylinder head on wood blocks to prevent damage to the combustion face.
Use a hoist or hydraulic arm and remove the cylinder head.
This component or assembly weighs greater than 23 kg [50 lb]. To prevent serious personal injury, be sure to have assistance or use appropriate lifting equipment to lift this component or assembly.
Valve Seat
Inspect the valves for indications of leaking or burning. If indications of leaking or burning are found, the valves and the seats must be resurfaced.
Test the cylinder head for damage. Set the head down with the exhaust ports facing up. Pour fuel into one of the exhaust ports until it is full. Set the container of fuel down, and start a timer.
Use the vacuum tester, Part Number ST-1257, to inspect the seal between the valve and the valve seat.
The valve vacuum tester is not recommended for use on used cylinder heads. See the Leak Test section of this procedure for the recommended procedure to check used heads.
The valve vacuum tester can be used to test all Cummins engine models. The seal ring, Part Number ST-1257-35, and vacuum cup, Part Number 3376100, are used on the M11 cylinder heads.
If the elapsed time is less than 10 seconds, perform the following checks:
Repeat the test to be sure the equipment is operating properly.
Use a mallet to hit the valve stem lightly to make sure the valve is seated. Repeat the test.
Apply a thin layer of grease on the outside diameters of the insert and the valve head. Repeat the test. The grease pattern will show the point of leakage.
A break in the grease seal pattern will indicate leakage between the valves and valve seat or the valve seat insert and the cylinder head.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Use a gasket scraper to clean the cylinder block deck surface.
Use Scotch-Brite™ 7448 abrasive hand pad, Part Number 3823258, or equivalent, and solvent to remove any residual gasket material from the cylinder block deck surface.
Make sure the cylinder head capscrew holes are clean and free of debris, oil, or coolant.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.
CAUTION
If the oil passages are not plugged or covered before cleaning, a crankshaft failure can occur.
Use Scotch-Brite™ 7448 abrasive hand pad, Part Number 3823258, or equivalent, and solvent to clean the cylinder head combustion face.
Prior to disassembly, measure and record the valve recess and valve tip height above the top deck of the cylinder head. See Clean and Inspect for Reuse in this procedure.
Install a wood block between the valves and head holding fixture to support the valves.
Use the valve spring compressor, Part Number ST-448, the compressor threaded adapter, Part Number 3376850, and the compressor adapter, Part Number 3376851, to compress the valve springs.
Prior to removing the valve guides, measure and record the valve guide inside diameter (I.D.) and height. See the Clean and Inspect for Reuse step in this procedure.
Prior to removing the valve seat inserts, see Leak Test and Inspect for Reuse in this procedure. The condition of the valve, the amount of recess, and the sealing of the valve on the seat insert, all help determine whether or not a seat insert needs to be replaced.
Use slide hammer assembly, Part Number 3376616, and valve seat extractor, Part Number 3376146, to remove the valve seat inserts from the cylinder head.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Use a wire brush and solvent to clean the deposits from the valve seat insert bores.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Use solvent to clean the injector bore.
Dry with compressed air.
Inspect the injector seat surface in the bottom of the injector bore.
If the bead in the cylinder head is not smooth, the injector bore must be repaired.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
When using compressed air to clean capscrew holes, always wear safety glasses or a face shield to protect the eyes. Personal injury can result.
Use a flexible brush and solvent to clean the valve guide bores in the cylinder head. Dry with compressed air.
Do not use caustic or acid solutions to clean the cylinder head capscrews. Damage to the capscrew can occur.
Clean the cylinder head capscrews with a petroleum-based solvent.
Clean the capscrews thoroughly with a wire brush, with a wire wheel (soft), or use a nonabrasive bead blast to remove deposits from the shank and threads.
Using flange head capscrews with the torque plus angle method of installation places the capscrews beyond the yield point and permanently stretches the capscrews. These capscrews can be reused throughout the life of the engine unless the capscrew exceeds the specified free length. The free length must be checked to reduce the possibility of bottoming in the block during installation.
Cylinder head capscrew length gauge, Part Number 3823546, has been designed to check capscrew free length.
NOTE: The new capscrews are coated with a grey coating and do not have the 90° mark on the capscews head.
To check the capscrew free length, place the head of the capscrew in the appropriate slot, long or short, with the flange against the base of the slot.
Use the slot marked for L10 cylinder head capscrews.
The capscrew can also be checked using a set of calipers. The maximum allowable free length is measured from the bottom of the flange to the end of the capscrew (dimension X).
Measure the inside diameter (I.D.) of the valve seat insert bore in the cylinder head.
Insert Bore Inside Diameter (I.D.)
mm
in
45.920
MIN
1.8073
45.935
MAX
1.8085
If the valve seat insert bore inside diameter does not meet the specifications given, see the oversize valve installation insert installation instructions in the Assemble step of this procedure.
Measure the inside diameter (I.D.) of the valve guide bore in the cylinder head.
Valve Guide Bore Inside Diameter (I.D.)
mm
in
16.480
MIN
0.6488
16.500
MAX
0.6496
If the valve guide bore is worn larger than the maximum specified, the valve guide bore can be machined, and a 0.51 mm [0.02 in] oversize valve guide installed.
Measure the valve seat insert bore depth in the cylinder head.
Insert Bore Depth (Standard insert)
mm
in
9.40
MIN
0.370
9.50
MAX
0.374
If the valve seat insert bore depth does not meet the specifications given, see the Cylinder Head Oversize Valve Seat Insert Installation in the Assemble step of this procedure.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Do not pressure-test the cylinder head with the valves and valve springs installed. Water entering the cylinder head can not be dried thoroughly and will damage the valve guides and valve stems.
Coolant Passage
Install cylinder head water test fixture, Part Number 3376082:
Install gasket, Part Number 3376084 (1)
Install test plate, Part Number 3376658 (2)
Install the 32 cylinder head capscrews and 32 (M14 x 1.50) nuts.
This component or assembly weighs greater than 23 kg [50 lb]. To prevent serious personal injury, be sure to have assistance or use appropriate lifting equipment to lift this component or assembly.
Connect a regulated air supply hose to the test fixture plate. Apply air pressure.
Measurements
kpa
psi
Air Pressure
276
40
Use a nylon lifting strap and a hoist to place the cylinder head in a tank of heated water.
Completely submerge the cylinder head in the water.
This component or assembly weighs greater than 23 kg [50 lb]. To prevent serious personal injury, be sure to have assistance or use appropriate lifting equipment to lift this component or assembly.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Remove the cylinder head and parts from the cleaning tank.
Use fuel passage cleaning brush, Part Number ST-876, to clean the fuel and oil passages with solvent. Dry with compressed air.
Inspect the fuel and oil passages to make sure they are clean.
Use the magnetic particle residual method to inspect the valves for cracks.
The exhaust valves contain two types of metal, and must be inspected by the coil shot method. There will be a magnetic leakage apparent at the point where the two metals are welded together. The leakage will appear as a wide pattern of magnetic particles.
Magnetize the valves in a coil of 100 to 200 amperes.
The intake valves contain only one type of metal and must be magnetized and inspected in two directions. Use the Magnaglo™ coil method and inspect with residual Magnaglo™ the same as exhaust valves.
Magnetize the intake valves again with a headshot at 500 to 700 amperes.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Both ends of a crack between the valves must be visible. If one end of a crack extends into the valve seat insert bore behind the valve seat insert, then the condition of the cylinder head is questionable. To be sure that the cylinder head is in good condition, remove the valve seat insert. See the Disassemble Section in this procedure.
When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.
WARNING
Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.
WARNING
Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.
Remove all magnetism and use solvent to clean the cylinder head. Dry with compressed air.
The cylinder head must be thoroughly cleaned after using the magnetic crack detector to remove all of the iron fragments.
Install the base and swivel of valve seat insert tool, Part Number ST-275, on the cylinder head to guide the valve seat driver. Install valve guide arbor, Part Number ST-804-1.
The insert chamfer (1) must be installed toward the bottom of the counterbore.
Use valve seat driver, Part Number 3376105, to drive the valve seat insert into the counterbore.
Make sure the insert is at the bottom of the counterbore.
Support the cylinder head in the Part Number ST-583 head holding fixture to prevent damage to the injector tip that protrudes from the combustion face.
Install the injector into the cylinder head without the o-rings.
Do not use excessive force or the seal will be damaged.
Use valve seal driver, Part Number 3823946, to install the valve seals on the valve guides.
Position the seal on the tool arbor.
Insert the arbor into the top of the guide and tap the tool with a plastic mallet to seat the bottom of the seal against the machined step on the valve guide.
Use valve spring compressor, Part Number ST-448, compressor thread adapter, Part Number 3376850, and compressor adapter, Part Number 3376851, to compress the valve springs.
Always use new collets when rebuilding the cylinder head.
Use vacuum tester, Part Number ST-1257, with vacuum cup, Part Number 3376100, to vacuum test the valve seating. See the Cylinder Head – Vacuum Test Valve Seating in this procedure.
Dependent upon the fuel plumbing option, one fuel inlet passage insert must be removed to allow fuel flow to the injectors. If the insert is not removed, the engine will not start.
Remove the pipe plug and use a sharp object to pull the insert from the hole.
Install the cylinder head lifting bracket, Part Number 3822476, with two rocker lever support mounting capscrews and two long rocker housing mounting capscrews.
This component or assembly weighs greater than 23 kg [50 lb]. To prevent serious personal injury, be sure to have assistance or use appropriate lifting equipment to lift this component or assembly.
CAUTION
Do not drop the cylinder head on the cylinder head gasket. The gasket material can be damaged.
Use a new gasket and install the cylinder head.
Use clean 15W-40 oil to lightly coat the cylinder head capscrew threads and bottom of the flange.
Allow the excess oil to drain from the capscrew threads.
All 32 capscrews new and old must be rotated 180 degrees after they have been tightened according to Step 2. Make a mark on the cylinder head as a reference. Rotate the capscrew until the mark on the cylinder head is more than two flats and less than three flats.
When using torque plus angle, the tolerance on the 180 degree angle of rotation is between two and three flats. If the capscrew is unintentionally rotated beyond three flats, do not loosen the capscrew. The clamp load is still acceptable. However, rotating the capscrew beyond three flats reduces the number of potential reuses.
NOTE: This torque procedure is applicable to both the old and new capscrews.
Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.
WARNING
Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.
Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.
WARNING
Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.
Install the STC oil manifold.
Install the elbow from the rocker lever housing.
Install the three STC oil manifold mounting capscrews from inside the rocker lever housing.
Install the oil supply line from the STC control valve to the STC oil manifold connection on the side of the rocker housing. Refer to Procedure 006-037 in Section 6.
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