Valves and Unit Injectors, Adjustment

Service BulletinMack Trucks, Inc.Greensboro, NC USA Trucks

Date Group No. Release Page

5.2010 214 87 01 1(11)

Valves and Unit Injectors

Adjustment

MP7 EPA2007, MP7 EPA2010

Valves and Unit Injectors, Adjustment

T2022275

This information covers the correct procedure for adjusting the valves and unit injectors onMP7 EPA2007 and MP7 EPA2010 engines.

Contents• “Special Tools”, page 2

• “Valves and Injectors, Adjustment”, page 3

Note: Information is subject to change without notice.Illustrations are used for reference only and may differ slightly from the actual vehiclebeing serviced. However, key components addressed in this information are representedas accurately as possible.

PV776-88948798 USA39019

Mack Trucks, Inc. Date Group No. Release PageService Bulletin 5.2010 214 87 01 2(11)

ToolsSpecial Tools

For special tools ordering instructions, refer to Tool Information, group 08.

85111158VEB Shim Kit

9996956Flywheel Turning Tool

85111377Feeler Gauge Set


Service Procedures2140-05-02-03

Valves and Injectors, Adjustment

You must read and understand the precautions andguidelines in Service Information, group 20, "GeneralSafety Practices, Engine" before performing thisprocedure. If you are not properly trained and certifiedin this procedure, ask your supervisor for training beforeyou perform it.

Special tools: 85111158, 9996956, 85111377

Valve and Unit Injector, Adjustment

11Apply the parking brake and place the shift lever inneutral.

22Remove all cables from ground (negative) batteryterminals to prevent personal injury from electrical shock.

3

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3Remove the valve cover. Refer to Group 21 forprocedure.


4

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4Remove the cover at the bottom of the flywheel housingand install the flywheel turning tool 9996956.


Inlet Valve AdjustmentTiming marks for basic camshaft timing and adjustment ofthe valves and unit injectors are located at the rear of thecamshaft just forward of the No. 7 rear bearing journal.Some engines also have the timing markings located onthe front face of the camshaft at the No. 1 front bearingjournal. Two lines at the top of the bearing cap mark thealignment point for positioning of the camshaft and makingthe adjustment.

Engines without engine brake— Adjust the inlet valves,exhaust valves and injectors using the timing marks 1–6on the camshaft.

Engine with engine brake — Adjust the inlet valvesand the injectors using the timing marks 1–6. Adjust theexhaust valves using the timing marks identified with a Vin front of the number, i.e., V1 or V6.

Camshaft settings for adjustment of the valves and unitinjectors are shown in the following chart.

Camshaft Markings

CamPosition Injector Intake

Exhaust(withoutEngineBrake)

Exhaust(withEngineBrake)

5 X X X

V6 X

3 X X X

V2 X

6 X X X

V4 X

2 X X X

V1 X

4 X X X

V5 X

1 X X X

V3 X


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Rear of Cam Shaft Showing Timing Marks

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Front of Cam Shaft Showing Timing Marks

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1

Using the flywheel turning tool 9996956, turn the engineover manually in the normal direction of rotation to theappropriate camshaft marking for adjustment of the inletvalves and unit injector of that cylinder.


2

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2Using a feeler gauge, check the clearance between therocker arm adjustment screw and the valve bridge of theinlet valves. The inlet valve clearance should be 0.20 ±0.05 mm (0.008 ± 0.002 inch).

33If the clearance is not within specification, loosen thelocknut and adjust the clearance as required. Hold theadjustment screw to prevent it from turning and tightenthe locknut to 38 ± 4 Nm (28 ± 3 ft-lb).

Unit Injector Adjustment1

1To adjust the unit injector at the same cylinder location,loosen the locknut and back off the adjusting screw untilit no longer makes contact.

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2Turn the adjusting screw in until it contacts the unitinjector (zero clearance). Then, tighten the adjustingscrew an additional 4 flats or 240 degrees of clockwiserotation.

Zero clearance,Plus, 4 flats or 240 degrees of clockwise rotation

33Hold the adjusting screw and tighten the locknut to 52± 4 Nm (38 ± 3 ft-lb).


Exhaust Valve Adjustment (withoutEngine Brake)

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1

At the current camshaft setting, adjust the exhaustvalves following the same procedure described abovefor adjustment of the inlet valves. However, the valveclearance specification is different, at 0.80 ± 0.05 mm(0.031 ± 0.002 inch).

22Using the flywheel turning tool, turn the engine overmanually to the appropriate marking for the next cylinder.Adjust the inlet valves, unit injector and exhaust valvesat that cylinder.

Exhaust Valve Adjustment (withEngine Brake)

1

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Image Shows Rear Cam Shaft Timing Marks

1Using the flywheel turning tool, turn the engine over sothat the appropriate V number marking for the respectiveexhaust valves is between the lines on the rear and/orfront camshaft bearing cap.


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2Press down on the exhaust rocker arm to release thepressure from the engine brake rocker arm piston.

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3Measure the clearance between the rocker arm pistonand the shim on top of the bridge as shown in the figure.The clearance should be 2.00 ± 0.05 mm (0.079 ± 0.002inch).

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4If clearance is not within specification, adjust theclearance as required, using shims placed on top of thevalve bridge.

1 Remove the shim retaining screw and remove theshim(s).

2 Determine the thickness of the shim(s) required tomatch the measured clearance.

Note: DO NOT use more than two shims. Shims areavailable (shim kit No. 85111158) in 0.05 mm (0.002 inch)increments with the thickness marked on the surface.If two shims are required to take up the clearance, theshims should be of nearly equal thickness.


3 Clean the valve bridge and shim(s). Place the shim(s)in position on the bridge, install the retaining screwand tighten to 38 ± 4 Nm (28 ± 3 ft-lb). Hold the bridgesecurely while tightening the retaining screw.

55With the required shim(s) in place and secured, recheckthe clearance between the exhaust valve rocker arm andthe valve bridge.

Note: Mark the respective rocker arm as each valveadjustment is completed.

Continuation of Adjustments1

1

Continue the procedure by turning the engine to theappropriate timing marks and adjusting the valves andunit injectors at each of the remaining cylinders. Followthe steps described in the preceding procedure to adjustthe inlet and exhaust valves, and unit injector at eachcylinder.

Note: Ensure that the turning tool is well greased beforeattempting to turn the flywheel.

22After all adjustments have been made, use the flywheelturning tool to turn the engine over manually two completerevolutions. This is done to ensure that no piston-to-valvecontact occurs. If contact does occur, readjust the valvesas needed.

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3Remove the flywheel turning tool, 9996956, and reinstallthe cover.


Final Steps1

1Clean the valve cover mounting surface on the cylinderhead and inspect the valve cover gasket for damage. Thegasket must be replaced if any damage is found, All oldsealant must be removed from the gasket prior to re-use.

22Apply 2 mm (0.079 inch) of approved sealant to theparting lines between the cylinder head and the timingcover on both sides of the cylinder head.

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3Install valve cover. Refer to Group 21 for procedure.

44Install all previously removed cables to the ground(negative) battery terminals.

55Start the engine and check for leaks. Once normaloperating temperature is attained, let the engine idle foran additional five minutes. During this time, the EngineControl Module (ECM) will perform its own cylinderbalancing, resulting in smooth engine idling.

Note: During cylinder balancing, do not use any form ofpower consuming equipment, such as power take-off orair conditioning.

66After engine shutdown, replenish fluids as necessary.

Valves and Unit Injectors, Adjustment

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