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DESCRIPTION

Yoke and valve adjustments are done in two stages on E7 engines. Adjust the yoke clearance first, then adjust the valve lash. Make sure both adjustments are done in firing order sequence. Manually rotate the engine in normal rotation direction until pointer in flywheel housing aligns with valves 1 and 6 mark on the flywheel and the No. 1 piston on the compression stroke.

The flywheel has a stamped timing scale consisting of TC through 45 degrees of engine travel for setting and checking pump-to-engine timing. Also, the flywheel has three stamped locations at 120-degree intervals for valve settings.

Some E7 engines are equipped with a pointer on the timing gear cover and marks on the vibration damper. To adjust the yoke and valves on these engines, bar engine in normal rotation direction until the TC mark on the damper (with the No. 1 piston on the compression stroke) aligns with pointer marked VALVE. This provides the 30-degrees-after-TDC relationship for valve lash adjustment necessary with the E7 camshaft design.

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Yoke and valve adjustments must be made under static conditions with coolant temperature below 100 ° F (37 ° C).


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E7 engine firing order is 1-5-3-6-2-4.


 

 

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Some E7 engines built in early 1995 may be equipped with flywheels that have missing or illegible valve adjustment markings. If this problem is encountered, a typical flywheel can be marked while the engine is in the chassis.


TYPICAL FLYWHEELS

On a typical flywheel, the TC markings, and the valve adjustment markings, are directly in line with the clutch mounting bolt/bolt holes. To determine if the engine is equipped with a typical flywheel, view the flywheel through the timing access hole in the flywheel housing. Align the TC markings with the timing pointer. If the flywheel is typical, there should be a clutch mounting bolt/bolt hole directly in line with the TC marking. In this case, the valve adjustment markings should be in line with a clutch mounting bolt at three locations. (Refer to Figure 2 -- Flywheel Marks .)

There are 12 clutch mounting bolt holes in the flywheel, but only 8 of these holes are used to mount the clutch. Every third bolt hole, for a total of four, is not used. These holes are in an open area between the clutch mounting flanges. The unused holes are easy to see through the timing access hole in the flywheel housing. The bolt holes where there is a clutch mounting bolt are more difficult to see because the clutch mounting bolt head is somewhat rearward of the timing access opening. To aid in counting the clutch mounting bolt/bolt holes, keep in mind that there is slightly over four inches between one bolt hole and the next. Locating the clutch mounting bolts may be made easier by removing the bell housing inspection cover and viewing or feeling for the bolts through the bell housing.

After verifying that there is a clutch mounting bolt/bolt hole in line with the TC mark, the next step is to locate the three locations where the valve adjustment marks should be. Put a temporary (chalk, grease pencil, paint, etc.) mark at each of the three locations. Proceed as follows:

1.

Beginning with the TC mark aligned with the timing pointer, rotate the engine in the direction of normal rotation (counterclockwise, viewed from rear) to the next clutch mounting bolt/bolt hole. Temporarily mark this location for cylinders 1 and 6.

2.

Continue rotating the engine in the normal direction and count the clutch mounting bolt/bolt holes as they pass the timing access opening. At the fourth mounting bolt/bolt hole, make a temporary mark on the flywheel for cylinders 2 and 5.

3.

Rotate the engine another four mounting bolt/bolt holes and make a temporary mark on the flywheel for cylinders 3 and 4.

4.

Rotate the engine another three clutch mounting bolt/bolt holes and verify that the flywheel is at the TC mark. Then, rotate the engine one more bolt/bolt hole and verify that the flywheel is at the temporary mark made for cylinders 1 and 6.

5.

Permanently mark the flywheel at this location for cylinders 1 and 6. To gain access, rotate the engine slightly so that the area to be marked is either to the right or left side of the timing pointer. Place a chisel mark directly in line with the clutch mounting bolt/bolt hole. Then, stamp or electric-etch the cylinder numbers on either side of the chisel mark.

6.

Rotate the engine to the remaining locations and make sure to count the clutch mounting bolt/bolt holes to verify the locations of the temporary markings. Once verified, permanently mark each location as described.

NON-TYPICAL FLYWHEELS

If the engine is equipped with a non-typical flywheel, the TC markings will be halfway between two clutch mounting bolts. If this type of flywheel has no valve adjustment markings, it should be replaced. Also, any flywheel which has no markings for injection pump timing should be replaced, even though piston travel method of injection pump timing could be used.

 

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On mechanically governed engines, before barring engine for any reason, secure injection pump stop lever in stop position.

Make sure that adjusting screws are retracted upward in the rocker arms. If they extend too far below the rocker arm, the push rods can be bent when tightening the rocker arm assembly brackets.


Refer to Figure 1 -- Engine Crankshaft Rotation , Figure 2 -- Flywheel Marks and Figure 3 -- Yoke Adjusting Screw and Locknut .

1.

Using engine barring socket J 38587-A, manually rotate engine in normal rotation direction until pointer in flywheel housing aligns with valves 1 and 6 mark on the flywheel and the No. 1 piston is on the compression stroke (or until the pointer marked VALVE aligns with the TC mark on the vibration damper, if equipped).

Figure 1 -- Engine Crankshaft Rotation 
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1. Barring socket J 38587-A

2. Flywheel housing

3. Flywheel


Figure 2 -- Flywheel Marks 
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2.

Back off the valve rocker adjusting screws.

3.

Loosen the No. 1 cylinder yoke adjusting screw locknuts.

4.

Exert moderate force on the yoke by pressing on the rocker arm slipper end. Turn down the yoke adjusting screw until it makes solid contact with the outboard valve stem tip, as sensed by a light drag on the adjusting screw.

5.

Turn adjusting screw an additional 1/6 turn (60 degrees) clockwise.

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A 1/6 turn is equal to one flat on the adjusting screw locknut.


6.

Hold the yoke adjusting screw in this position while tightening the adjusting screw locknut. Torque locknut to 33 lb-ft (45 N · m) using torque wrench J 24407 or equivalent.

Figure 3 -- Yoke Adjusting Screw and Locknut 
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CHECKING YOKE ADJUSTMENT

Refer to Figure 4 -- Checking Yoke Adjustment .

7.

Insert a 0.010-inch (0.254 mm) thickness gauge between the yoke and valve stem, at both the inboard and outboard locations.

8.

Exert moderate force on the yoke by pressing on the rocker arm slipper end. An equal drag should be felt on both thickness gauges. If drag is unequal, readjust the yoke adjusting screw, as required.

Figure 4 -- Checking Yoke Adjustment 
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1. Thickness gauge

2. Yoke

 

Refer to Figure 5 -- Inlet Valve Adjustment .

Inlet valve lash clearance is 0.016 inch (0.406 mm).

1.

Place a 0.016-inch (0.406 mm) thickness gauge between the rocker arm and yoke on the No. 1 cylinder.

2.

Turn the adjusting screw until a light drag is felt on the thickness gauge.

3.

After setting adjustment screw, tighten locknut. Torque locknut to 40 lb-ft (54 N · m) using torque wrench J 24407 or equivalent.

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Do not allow the adjustment screw to turn.


4.

After tightening locknut, recheck valve lash clearance. Readjust as necessary.

Figure 5 -- Inlet Valve Adjustment 
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1. Thickness gauge

2. Adjusting screw and locknut

 

Refer to Figure 6 -- Exhaust Valve Adjustment .

Exhaust valve clearance is 0.024 inch (0.610 mm) for engines produced through engine serial No. 6F in April 1996 and 0.028 inch (0.711 mm) for engines produced after engine serial No. 6F in April 1996.

1.

Place the proper thickness gauge between the rocker arm and yoke on the No. 1 cylinder.

2.

Turn the adjusting screw until a light drag is felt on the thickness gauge.

  • If equipped with a Dynatard engine brake, use Dynatard valve-lash adjusting wrench J 37092 to rotate adjusting screw. Press downward with hand on the hydraulic lash adjuster while gauging valve lash. Adjust the lash until a light drag is felt on the thickness gauge.

3.

After adjustment is complete, tighten locknut. Torque locknut to 40 lb-ft (54 N · m) using torque wrench J 24407 or equivalent.

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Do not allow the adjustment screw to turn.


4.

Recheck valve lash clearance after tightening locknut. Readjust as necessary.

Figure 6 -- Exhaust Valve Adjustment 
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1. Thickness gauge

2. Adjusting wrench J 37092

Refer to Figure 1 -- Engine Crankshaft Rotation .

5.

Using engine barring socket J 38587-A, manually rotate engine in normal rotation direction 120 degrees until pointer in flywheel housing aligns with the "5" mark on the flywheel. The No. 5 piston will be on the compression stroke. If engine is equipped with a pointer mounted on the timing gear cover and marks on the vibration damper, rotate the engine until the pointer marked VALVE aligns with the "5" mark on the vibration damper.

6.

Adjust the yoke and valve lash as previously outlined for the No. 1 cylinder.

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E7 engine firing order is 1 - 5 - 3 - 6 - 2 - 4.


7.

Continue adjusting yoke and valve lash for the remaining cylinders, in firing order. Rotate crankshaft to place each piston 30 degrees past TDC.

Engine Crankshaft Rotation 
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1. Barring Socket J 38587-A

2. Flywheel Housing

3. Flywheel

Check the push rods. Replace any push rods that have loose ends, are bent, or show signs of excessive wear.

Refer to Figure 64 -- Valve Lifter/Push Rod Identification.

The current E7 valve lifter has no hole in the center of the stem. In conjunction with this change, the E7 inlet and exhaust (nonbrake engine) push rods have a 0.060-inch (1.524 mm) maximum flat or dimple on the ball end. The push rod part number is etched or roll-stamped on the push rod.

The non-current push rod should be used only with the non-current lifter. If the non-current push rod with the wide flat or dimple is used in the current valve lifter which has no center hole, it may create an undesirable wear pattern in the lifter socket.

Mixing current and non-current valve lifters is permissible when using the correct lifter/push rod combination.

  • Current push rod can be used with either valve lifter.

  • Do not use non-current valve lifter to service current valve lifter.

Only Dynatard exhaust push rods are not affected and can be used with current and non-current valve lifters. Dynatard intake push rods still need to be updated to current push rods when using current valve lifters.

Figure 64 -- Valve Lifter/Push Rod Identification 
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1. Push Rods Smoothly Rounded

2. 0.200" Maximum Flat or Dimple

3. With Center Hole

4. Without Center Hole

5. 0.060" Maximum Flat or Dimple

A. Current 369GC334

B. Non-Current 369GC329A

C. Non-Current 72GC347A

D. Inlet Lobe

 

All E7 production engines starting with serial No. 2X0000 and above, feature valve lifters with no hole as well as inlet and nonbrake push rods with 0.060 inch (1.524 mm) maximum flat or dimple on the push rod ball end.

 

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Used push rods have established wear patterns. Push rods being returned to service should be installed in the same position from which they were removed.


1.

Apply lubricating oil to spherical end of the push rod and insert it into the lifter opening. Ensure that it has engaged the lifter by lifting it slightly. If the lifter has been properly contacted, some resistance will be felt in the rod as the lifter is raised.

2.

Repeat step 1 until all 12 push rods are in position.

 

 

There are two exhaust valves and two inlet valves for each cylinder. Each rocker arm, in conjunction with the valve yoke, operates both valves together, in a set (exhaust or inlet), per cylinder.

 

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Used yokes have established wear patterns. Yokes being returned to service should be installed in the same position from which they were removed.


Refer to Figure 65 -- Valve Yoke.

1.

Lubricate the yoke guide pins (5) with clean engine oil.

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If the engine is equipped with a Jake Brake, the exhaust valve yokes will have a larger rocker arm contact surface. The yokes with the larger surface must be installed on pins corresponding with the Jake Brake actuators.


2.

Place the valve yokes (2) on the yoke guide pins from which they were removed. Slightly rock the yokes from side to side to be sure they are seated on the valve stems (4).

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Engines equipped with Jake Brake: Effective January 1994 (engine serial No. 401269), the E7 Jake Brake yoke was manufactured with metric threads utilizing the Spiralock™ thread form. Refer to [213 NB] VALVE YOKE, VALVE LASH AND SLAVE PISTON ADJUSTMENTS (JACOBS BRAKE ENGINE) for details regarding correct method to loosen the yoke adjusting screw.

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