Usage:
Introduction
If 3406B and 3406C engines experience excessive oil consumption and/or slobber, the condition can sometimes be attributed to excessive exhaust valve guide wear.
This instruction lists the service tooling, modification of service tooling, parts, and procedures needed in order to replace worn exhaust valve guides without removing the cylinder head.
The replacement of the exhaust valve guides, without removing the cylinder head, maintains the integrity of the cylinder head to engine block seal.
Some of the tooling in 1U-9347 Valve Spring Compressor Group and 1U-9570 Dowel Puller Group must be modified (machined) in order to use for this repair.
Tooling Modification
1U-9347 Valve Spring Compressor Group
Plate Assembly
The plate assembly is part of 1U-9347 Valve Spring Compressor Group.
Illustration 1 provides information for machining the plate assembly: Instruction (1) to "Remove This Area". Dimension (A) 38 mm (1.5 in).
The plate assembly is used to compress the four valve springs at each cylinder.
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Machine the plate assembly to the dimensions shown in Illustration 1.
The plate assembly should be machined parallel to the horizontal centerline a distance (A) of 38 mm (1.5 in).
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The modification of the plate assembly will provide adequate clearance with the rocker arm stands.
This will allow the valve guides CLOSEST TO THE EXHAUST MANIFOLD OUTBOARD GUIDES to be replaced without draining the engine coolant or removing the rocker arm shaft assembly.
1U-9570 Dowel Puller Group
1U-9572 Extractor
The 1U-9572 Extractor is part of 1U-9570 Dowel Puller Group.
Illustration 2 provides information for modifying 1U-9572 Extractor: Dimension (B) 17.53 mm (.690 in) to 17.63 mm (.694 in). Dimension (C) 38 mm (1.5 in).
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Machine 1U-9572 Extractor to the dimensions shown in Illustration 2.
The inside diameter (B) of the slotted end of 1U-9572 Extractor must be enlarged from a diameter of 17.53 mm (.690 in) to 17.63 mm (.694 in).
The increased diameter (C) should be maintained to the end of the slots or 38 mm (1.5 in).
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The increased diameter will allow 1U-9572 Extractor to fit over the valve guide.
1U-9577 Forcing Collar
The 1U-9577 Forcing Collar is part of 1U-9570 Dowel Puller Group.
Illustration 3 provides information for machining 1U-9577 Forcing Collar: Instruction (2) to "Remove This Area". Dimension (D) 46 mm (1.8 in). Dimension (E) 57.0 mm (2.24 in). Notice (3) of "Knurled End".
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Machine 1U-9577 Forcing Collar to the dimensions shown in Illustration 3.
The outside diameter of 1U-9577 Forcing Collar must be machined to a reduced diameter (D) of 46 mm (1.8 in) and to a length (E) of 57.0 mm (2.24 in).
NOTE: DO NOT machine the knurled end (3) of 1U-9577 Forcing Collar.
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The modification of 1U-9577 Forcing Collar will provide adequate clearance between the outside of 1U-9577 Forcing Collar, cylinder head bridge dowel, and the fuel injection nozzle adapter in the cylinder head.
9U-7349 Valve Guide Driver Assembly
Illustration 4 provides information for machining 9U-7349 Valve Guide Driver Assembly: Instruction (4) to "Remove This Area". Dimension (F) 13 mm (.5 in).
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Machine 9U-7349 Valve Guide Driver Assembly end to the seating shoulder a length (F) of 13 mm (.5 in).
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The modification of the driver assembly will provide adequate clearance between the pilot end of the tool and the end of the valve when installing a valve guide in the cylinder head with the valves in place.
Using The Modified Tooling To Install Valve Guides Without Removing The Cylinder Head
This repair does not require the removal of the cylinder head.
Refer to the Service Manual for the procedures to remove the required parts to install the exhaust guides.
1. Remove the cylinder head valve cover, base, and related components.
2. Remove the engine exhaust brake (if equipped).
3. Remove the rocker shaft assemblies and bridges.
4. Rotate the crankshaft until pistons:
- * Number 1 and number 6, or
- * Number 3 and number 4, or
- * Number 2 and number 5 are at the top of their travel.
- * Number 3 and number 4, or
Two cylinders may be worked on at each position.
When the pistons are positioned at the top of their travel position, the piston acts as a support to hold the valves in place. The valve stem keepers can then be removed without the valve dropping out of its guide.
NOTE: Refer to Special Instruction SEHS9032, Using the 1U-9347 Valve Spring Compressor Group, for the basic procedures to use the tooling. The Special Instruction is included in 1U-9347 Valve Spring Compressor Group.
The remaining procedures are the exception when using the modified tooling to replace the valve guides.
NOTE: The modified plate assembly can be used without removing the rocker arm stands. The 1U-9347 Valve Spring Compressor Group can be used to remove the valve keepers, rotocoil assemblies, valve springs, and valve guide washers.
5. Inspect the top of the valve guide for debris. Inspect the valve guide for side to side movement. The presence of debris and excessive valve guide movement indicate wear. When this occurs, the valve guide should be replaced.
6. Inspect the dowel hole in the bridge for debris. If any debris is present, clean the bridge, rotocoil assembly and surrounding area of the cylinder head.
Replacing a Valve Guide
NOTE: If the valve guides CLOSEST TO THE ROCKER ARM SHAFTS need replacing, the engine coolant MUST be drained and the rocker arm shafts removed. This will provide adequate clearance for the puller.
7. Slowly rotate the crankshaft to position the top of the valve stem at or slightly below the top of the cylinder head.
9. The area of assembly and the parts replaced must be cleaned before installation.
Clean the valve stem, valve guide bore in the cylinder head, and inside and outside surfaces of the new valve guide.
Lubricate the inside diameter of the new valve guide and the valve stem surface with 8T-2998 Lubricant.
Lubricate the outside surface of the new valve guide with clean engine oil.
NOTE: To prevent damage to the new valve guide during installation, slowly rotate the crankshaft so the top of the valve stem is approximately 6.4 mm (.25 in) above the top of the cylinder head.
10. Install the new valve guide over the valve stem. Seat the valve guide in the cylinder head using modified 9U-7349 Valve Guide Driver Assembly.
11. Rotate the crankshaft in order to raise the valves in the valve guides. Hold the valve stem while moving the valve up and down and while rotating the valve in the valve guide.
This will be an inspection for the required free movement of the valve in the new valve guide. It will also distribute 8T-2998 Lubricant evenly on all surfaces.
12. Install the guide washers, springs, rotocoil assemblies, and valve keepers.
Fill the recess in the top of the rotocoil assemblies with clean engine oil.
13. Repeat the procedures for each cylinder or pair of cylinders that require valve guide replacement.
14. After all worn valve guides have been replaced, install the remaining parts removed for the repair.