M11 Series – Service Manual – 003-004   Overhead Set

All overhead lash measurements must be made when the engine is cold, any stabilized coolant temperature at 60°C [140°F] or below.

Remove the rocker lever cover. Refer to Procedure 003-011.

WARNING  Do not straighten a bent fan blade or continue to use a damage fan. A bent or damaged fan blade can fail during operation and cause personal injury or property damage.

The valve set marks are located on the accessory drive pulley. The marks align with a pointer on the gear housing.

Use the accessory drive shaft to rotate the crankshaft.

The crankshaft rotation is clockwise when viewed from the front of the engine.

The cylinders are numbered from the front end of the engine.

The engine firing order is 1-5-3-6-2-4.

Rotate the accessory drive clockwise until the “A” valve set mark on the accessory drive pulley is aligned with the pointer on the gear cover.

Each cylinder has three rocker levers:

• The long rocker lever (E) is the exhaust lever.
• The center rocker lever is the injector lever.
• The short rocker lever (l) is the intake lever.

Reference the accompanying chart for valve rocker lever locations.

For CELECT™ and CELECT™ Plus Engines, when the “A” mark is aligned with the pointer, the intake and exhaust valves for cylinder number 1 must be closed. The injector plunger for cylinder number 1 must be at the bottom of its stroke. If these conditions are not correct, cylinder number 6 must be ready to check. Check the injector and valves on the cylinder that both the intake and exhaust valve rocker levers can be “rattled” by hand or the push tubes can be freely rotated.

Using a set of feeler gauges, measure the amount of valve lash clearance between the crosshead and rocker lever nose. Measure and record the intake and exhaust valve lash. If the valve lash is not within the specifications listed below, the valves must be adjusted.

NOTE: All adjusting screws must be tight to get an accurate measurement.

For measuring injector lash, install the dial indicator and the support from injector travel measurement kit, Part Number 3823610, or equivalent, so the extension, Part Number 3823595, or equivalent, for the dial indicator is on top of the injector rocker lever directly over the socket on the cylinder being checked.

Securely tighten the thumb screw (1) and the hold down capscrews (2 and 3) in place.

The tip of the dial indicator extension must rest on the rocker lever directly above the socket. If it does not, incorrect readings can result.

Loosen the thumb screw (3) and lower the indicator against the injector rocker lever until the stem is fully compressed.

Raise the indicator approximately 12.7 mm [0.500 inch] and tighten the thumb screw (3) to hold the indicator in position.

WARNING  The injector plunger is under spring tension. Do not allow the tool to slip. Serious personal injury can result.

Actuate the injector plunger three or four times to make sure the fuel has been removed from the injector assembly. Allow the lever to return slowly to prevent damage to the dial indicator.

Actuate the lever again; set the dial indicator at zero “0” while holding the injector plunger to the bottom of its travel.

Slowly release the actuator and check the dial indicator travel. Record the measured value.

If the injector lash setting is not within the specifications listed below, the injector must be adjusted.

For STC engines one pair of valves are measured at each pulley index mark before rotating the accessory drive to the next index mark.

Two crankshaft revolutions are required to measure the valve lash of all the valves.

Rotate the accessory drive clockwise until the “A” valve set mark on the accessory drive pulley is aligned with the pointer.

Check the valve rocker levers on cylinder number 5 to see if both valves are closed.

Both valves are closed when both rocker levers are loose and can be moved from side to side. If both valves are not closed, start with cylinder number 2.

Using a set of feeler gauges, measure the amount of clearance (lash) between the crosshead and rocker lever nose for the cylinder being measured. Measure and record both the intake and exhaust rocker lever lash.

After taking the valve lash measurements, rotate the accessory drive and align the next valve set mark.

Measure the appropriate valve lash.

Repeat the process until all of the lash measurements have been taken.

Compare valve lash measurements to the recheck limits. If the measurements are not within the recheck limits, the overhead must be reset.

If the engine is equipped with engine brakes, check the brake piston clearance. Refer to Procedure 020-001.

Install the rocker lever cover. Refer to Procedure 003-011.

All valve and injector adjustments must be made when the engine is cold (any stabilized coolant temperature at 60°C [140°F] or below).

Remove the rocker lever cover and gasket. Refer to Procedure 003-011.

WARNING  Do not straighten a bent fan blade or continue to use a damage fan. A bent or damaged fan blade can fail during operation and cause personal injury or property damage.

The valve set marks are located on the accessory drive pulley. The marks align with a pointer on the gear cover.

Use the accessory driveshaft to rotate the crankshaft.

The crankshaft rotation is clockwise when viewed from the front of the engine.

The cylinders are numbered from the front gear housing end of the engine.

The engine firing order is 1-5-3-6-2-4.

Each cylinder has three rocker levers:

• The long rocker lever (E) is the exhaust lever.
• The center rocker lever is the injector lever.
• The short rocker lever (l) is the intake lever.

Reference the accompanying graphic for valve rocker lever locations.

The adjustment can begin on any valve set mark. In the following example, the adjustment will begin on the “A” valve set mark with cylinder number 1 valves closed and ready for adjustment.

Rotate the accessory drive clockwise until the “A” valve set mark on the accessory drive pulley is aligned with the pointer on the gear cover.

When the “A” mark is aligned with the pointer, the intake and exhaust valves for cylinder number 1 must be closed. If these conditions are not correct, cylinder number 6 injector and valves must be ready to set. Set the injector and valves on the cylinder so that both the intake and exhaust valve rocker lever arms are loose and can be moved from side-to-side.

Both valves are closed when both rocker levers are loose and can be moved from side-to-side.

NOTE: Do not use excessive force when bottoming the plunger.

Loosen the injector adjusting screw locknut. Using a screwdriver (box end wrench if equipped with engine brakes) and the adjusting screw, bottom the injector plunger three or four times to remove the fuel.

Turn the adjusting screw in until you can feel it just bottom the plunger.

Back out the adjusting screw two flats, 120 degrees. Hold the adjusting screw, and tighten the locknut.

After setting the injector, set the valves on the same cylinder.

With the “A” valve set mark aligned with the pointer on the gear cover and both valves closed on the cylinder to be adjusted, loosen the adjusting screw locknuts on the intake and exhaust valves.

Select a feeler gauge for the correct valve lash specification.

Insert the feeler gauge between the top of the crosshead and the rocker lever pad.

Two different methods for establishing valve lash clearance are described below. Either method can be used; however, the torque wrench method has proven to be the most consistent. It eliminates the need to feel the drag on the feeler gauge.

• Torque Wrench Method: Use the inch-pound torque wrench, Part Number 3376592, or equivalent, normally used to set preload on top-stop injectors, and tighten the adjusting screw.

• Touch Method: Tighten the adjusting screw until a slight drag is felt on the feeler gauge.

Hold the adjusting screw in this position. The adjusting screw must not turn when the locknut is tightened.

• Without torque wrench adapter

• With torque wrench adapter, Part Number 3163196, or equivalent

After tightening the locknut to the correct torque value, check to make sure the feeler gauge will slide backward and forward between the crosshead and the rocker lever with only a slight drag.

If using the touch method, attempt to insert a feeler gauge that is 0.03-mm [0.001-in] thicker between the crosshead and the rocker lever pad. The valve lash is not correct when a thicker feeler gauge will fit.

If the engine is equipped with an engine brake.

After adjusting the injector, valves, and engine brakes (if equipped) on the appropriate cylinder, rotate the accessory drive pulley, and align the next valve set mark with the pointer on the gear cover.

If the valve cover gasket was not damaged, it can be used again. If the gasket was damaged, it must be discarded and a new one used.

Install the gasket on the cover.

Install the cover on the rocker lever housing.

Install the 16 isolators, spacers, and capscrews in the cover.

Tighten the capscrews in the sequence shown.

Valves and injectors must be correctly adjusted for the engine to operate efficiently. Valve and injector adjustment must be performed using the values listed in this section. The accompanying table gives the adjustment limits for STC engines.

Adjust the valves and the injectors at each 1,500 hour maintenance interval. If the valves and injectors have been adjusted during troubleshooting or before the 1,500 hour scheduled maintenance interval, adjustment is not required at this time.

All overhead, valve and injector, adjustments must be made when the engine is cold, any stabilized coolant temperature at 60°C [140°F] or below.

Remove the crankcase breather tube from the crankcase breather outlet.

Remove the 16 capscrews, isolators, and spacers from the cover.

Remove the rocker lever cover and gasket.

Each cylinder has three rocker levers:

• The long rocker lever (E) is the exhaust lever.
• The center rocker lever is the injector lever.
• The short rocker lever (I) is the intake lever.

Reference the illustration for valve rocker lever locations.

The crankshaft rotation is clockwise when viewed from the front of the engine.

The cylinders are numbered from the front gear cover end of the engine.

The engine firing order is 1-5-3-6-2-4.

The valves and injectors on the same cylinders are not adjusted at the same index mark on the accessory drive pulley on STC engines.

One pair of valves and one injector are adjusted at each pulley index mark before rotating the accessory drive to the net index mark.

Two crankshaft revolutions are required to adjust all the valves and injectors.

WARNING  Do not straighten a bent fan blade or continue to use a damaged fan. A bent or damaged fan blade can fail during operation and cause personal injury or property damage.

The valve set marks are located on the accessory drive pulley. The marks align with a pointer on the gear cover.

Use the accessory drive shaft to rotate the crankshaft.

The adjustment can begin on any valve set mark. In the following example the adjustment will begin on the “A” valve set mark with cylinder number five valves closed and cylinder number three injector ready for adjustment.

When the “A” mark is aligned with the pointer, the intake and exhaust valves for cylinder number five must be closed. If these conditions are not correct, cylinder number four injector and cylinder number two valves must be ready to set.

Both valves are closed when both rocker levers are loose and can be moved from side to side.

Loosen the injector adjusting screw locknut on cylinder number 3. Tighten the adjusting screw until all the clearance is removed from the injector train.

Tighten the adjusting screw one additional turn to seat the link correctly.

Loosen the injector adjusting screw until the STC tappet touches the top-cap of the injector.

Be sure to loosen the adjusting screw enough so there is no preload on the injector. This will be accomplished when the rocker lever is loose enough to move.

Place the STC tappet adjusting tool, Part Number 3823348, or equivalent, on the upper surface of the STC injector top-cap. Rotate the tool around the tappet until the tool’s locating pin is inserted into one of the four holes in the top of the tappet.

NOTE: Apply only enough force to the tool to hold the tappet in the maximum upward position. Excess force will cause the tool to break.

Apply thumb pressure to the tool handle to hold the tappet in the maximum upward position.

CAUTION  An overtightened setting on the injector adjusting screw will produce increased stress on the injector train and the camshaft injector lobe, which can result in engine damage.

Use torque wrench, Part Number 3376592, or equivalent, to tighten the adjusting screw while holding the tappet in the maximum upward position.

Hold the adjusting screw in this position. The adjusting screw must not turn when the locknut is tightened.

Tighten the adjusting screw.

• Without Torque Wrench Adapter

• With Torque Wrench Adapter (1)

The tappet tool must be removed before rotating the crankshaft to prevent damage to the tappet.

Remove the tappet adjusting tool.

Check to make sure the injector push rod can be rotated by hand. If it can not, the setting is too tight.

Adjust the valves on the appropriate cylinder according to the sequence chart before rotating the accessory drive to the next valve set mark.

Select a feeler gauge for the correct valve lash specification.

Insert the feeler gauge between the top of the crosshead and the rocker lever pad.

Two different methods for establishing valve lash clearance are described below. Either method can be used; however, the torque wrench method has proven to be the most concise. It eliminates the need to feel the drag on the feeler gauge.

• Torque Wrench Method: Use the inch-pound torque wrench. Part Number 3376592, or equivalent, (normally used to set preload on top stop injectors), and tighten the adjusting screw.

• Touch Method: Tighten the adjusting screw until a light drag is felt on the feeler gauge.

Hold the adjusting screw in this position. The adjusting screw must not turn when the locknut is tightened. Tighten the locknut.

Tighten adjusting screw.

• Without Torque Wrench Adapter

• With Torque Wrench Adapter (1)

After tightening the locknut to the correct torque value, check to make sure the feeler gauge will slide backward and forward between the crosshead and the rocker lever with only a slight drag.

If using the touch method, attempt to insert a feeler gauge that is 0.03 mm [0.001 in] thicker between the crosshead and the rocker lever pad. The valve lash is not correct when a thicker feeler gauge will fit.

After adjusting the valves, rotate the accessory drive and align the next valve set mark on the accessory drive pulley with the pointer on the gear cover.

Adjust the appropriate injector and valves following the Injector and Valve Adjustment Sequence Chart.

Repeat the process to adjust all injectors and valves.

After adjusting all the injectors and valves, check the torque on the adjusting screw locknuts to make sure none were overlooked.

If the valve cover gasket was not damaged, it can be used again. If the gasket was damaged, it must be discarded and a new one used.

Install the gasket on the cover.

Install the cover on the rocker lever housing.

Install the 16 isolators, spacers, and capscrews in the cover.

Tighten the capscrews in the sequence shown.

NOTE: To obtain maximum brake operating efficiency and prevent engine damage by piston-to-valve contact, complete the following instructions carefully.

After adjusting the exhaust valves on the appropriate cylinder, insert a feeler gauge 0.38 mm [0.015 in] between the slave piston and the actuating pin in the crosshead.

CAUTION  Do not tighten the adjusting screws too tightly. The engine can be damaged.

Turn the slave piston adjusting screw down until it touches the feeler gauge.

Hold the screw in position, and tighten the locknut.

• Without torque wrench adapter

• With torque wrench adapter, Part Number 3163196, or equivalent:

CAUTION  Failure to have the correct clearance can damage the engine.

After the slave piston adjusting screw locknut is tightened to the correct torque value, check the clearance with the feeler gauge again.