Modifying Exhaust Manifold Group To Provide Increased Clearance For Thermal Expansion{1059} Caterpillar

Modifying Exhaust Manifold Group To Provide Increased Clearance For Thermal Expansion{1059}

Usage:

3406B And 3406C Engines Equipped With Center-Mounted Turbocharger And Dry-Type Exhaust Manifolds

Introduction

This instruction lists the procedures, tools, parts, and machining dimensions in order to modify the exhaust manifold.

The modification consists of drilling mounting holes to a larger diameter and slotting (elongating) mounting holes. This process will provide increased clearance between the exhaust manifold components and the mounting studs in order to allow for thermal expansion.

The increased clearance will reduce exhaust manifold mounting stud breakage.

The exhaust manifold modification approximates the design of exhaust manifolds in current production. The suspect manifold should be inspected to ensure that it has not been modified or is not the previous design which can be later modified.

NOTE: A portion of the modification requires precision machining and some component replacement. Machine ONLY as referenced in the drawings and replace components with the part number(s) shown, NOT as referenced in other publications.

Modifying Exhaust Manifold Group

Remove Turbocharger And Exhaust Manifold

1. Refer to the Service Manual to remove the turbocharger and exhaust manifold.

2. The exhaust manifold, after removal from the cylinder head, must be separated at the center section's slip joints.

If the slip joints need to be heated in order to separate them, use a gas heating tip to heat the sections. Remove all mating slip joints while they are still hot.

Cleaning And Inspection

All exhaust components must be thoroughly cleaned and inspected.

NOTE: Glass beading is recommended for cleaning the exhaust components.

3. Clean the interior and exterior of the slip joints. Clean the manifold flanges at the manifold gasket surfaces.

Remove any flaking from the interior of the manifold sections; particularly at the divider wall of the turbocharger mounting flange.

4. Inspect all exhaust components for serviceability. Replace any suspect or damaged parts with new parts.

NOTE: There are different cast iron alloys used in the center section and manifold ends. If the manifold sections are to be replaced, the part numbers must be the same. The part numgers are cast on the manifold.

5. Remove any broken mounting studs from the cylinder head.

NOTE: Current production engines use 106-1792 Taperlock Studs and 108-3612 Spacers.

Clean and inspect the remaining mounting studs in the cylinder head. Remove and discard any suspect or damaged studs.

6. Clean the cylinder head at the manifold gasket surfaces.

7. Clean (chase) the internal threads (for the mounting studs) in the cylinder head with 4C-4993 Tap (Taper).

NOTE: The cleaning (chasing) should be performed with a hand-held tap holder. The mounting studs threads are a taper lock dimension and should ONLY be cleaned (chased) with 4C-4993 Tap (Taper) to the original depth.

For exhaust manifold center sections, other than 4W-4384 and 9L-5848 Exhaust Manifolds for mid-mount turbochargers, 4S-6137 Taperlock Stud and 2S-3770 Spacer should be used in place of 6L-8562 Taperlock Stud at number 3 cylinder.

The 4S-6137 Taperlock Stud is longer than 6L-8562 Taperlock Stud. Because of this interference the stud can not be used at this location with 4W-4384 and 9L-5848 Exhaust Manifolds.

8. Coat the threads of new 4S-6137 Taperlock Studs with 5P-3931 Thread Compound. Install 4S-6137 Taperlock Studs and tighten to a torque of:

* 25 ± 4 N·m (18 ± 3 lb ft)

Machining And Specialized Tooling

NOTE: This modification requires specialized tooling. The required Four Flute Double End D-400 End Mill(s) or equivalent may not be available in your area:

* 08-945-138 (Tin Coated) ... 27/64 inch (0.422 in).

* 08-945-139 (Uncoated) ... 27/64 inch (0.422 in.)

* 08-945-170 (Tin Coated) ... 17/32 inch (0.530 in).

* 08-945-173 (Uncoated) ... 17/32 inch (0.530 in).

Read through the following machining procedures in order to determine the tooling and parts that are needed.

Refer to Tooling Supplier, in this instruction, to order tooling.

Illustration 1. 4P-2659 and 4N-0270 Exhaust Manifold end sections: Each manifold group uses two of the same part number end manifolds.

Illustration 2. Mid-mount turbocharger: 4W-4384, 9L-5848, and 6I-3655 Exhaust Manifolds.

Illustration 3. Low or high mount turbocharger: 4W-4385 and 4N-0972 Exhaust Manifolds.

Illustration 4. High mount turbocharger: 2W-0483 Exhaust Manifold.

Illustration 5. Milling modification at location A: 63.5 mm (2.50 in) radius (1). 14.0 mm (.55 in) minimum (2). 0.89 mm (.035 in) (3).

1. Mill the manifold flanges at location A in order to eliminate spot facing.

NOTE: The radius milling as shown is not required. A straight horizontal mill cut is acceptable. The minimum flange thickness after milling is 14.0 mm (.55 in) (2).

Illustration 6. Drilling modification at location B: 15.0 mm (.59 in) (4). 13.5 mm (.53 in) (5).

2. Drill the existing 13.5 mm (.53 in) (5) flange hole(s) at location B to a diameter of 15.0 m (.59 in) (4).

Illustration 7. Slot modification at location C: 15.0 mm (.59 in) (6). 10.72 mm (.422 in) (7)

3. Horizontally slot the 10.72 mm (0.422 in) (7) diameter holes at location C to a width of 15.0 mm (0.59 in) (6). Center the slot on the existing hole. The slot height should be 10.72 mm (0.422 in) (7). Use a multi-flute end mill.

Illustration 8. Drilling modification at location D: 15.0 mm (.59 in) (8). 10.72 mm (.422 in) (9).

4. Drill the 10.72 mm (0.422 in) (9) diameter holes in the flanges at location D to a diameter of 15.0 mm (0.59 in) (8).

Illustration 9. Slot modification at location E: 15.0 mm (.59 in) (10). 13.5 mm (.53 in) (11).

5. Horizontally slot the 13.5 mm (0.53 in) (11) diameter holes in the flanges at location E to a width of 15.0 mm (0.59 in) (10). Center the slot on the existing hole. The slot height should be 13.5 mm (.53 in) (11). Use a multi-flute end mill.

NOTE: Early production manifolds had 12.7 mm (.50 in) diameter holes at location B and E. If so, first drill these holes to a diameter of 13.5 mm (0.53 in).

Assemble Exhaust Manifold

1. Inspect the male end of the manifold end sections in order to ensure they are clean, dry, and free of glass beading residue.

2. Apply a thin, uniform coat of 2P-2333 High Temperature Sealer on the male end of the manifold end sections.

NOTE: If the male end of the manifold end sections are grooved, fill the grooves with 2P-2333 High Temperature Sealer.

3. Apply a thin coat of clean engine oil to the female ends of the manifold center section. The engine oil will prevent the 2P-2333 High Temperature Sealer from sticking to the female end of the slip joints during assembly.

4. Assemble the manifold sections.

5. Install new 105-2873 Exhaust Manifold Gaskets over the exhaust manifold mounting studs.

6. Install the assembled manifold group over the mounting studs.

Illustration 1. 4P-2659 and 4N-0270 Exhaust Manifold end sections: Each manifold group uses two of the same part number end manifolds.

Illustration 2. Mid mount turbocharger: 4W-4384, 9L-5848, and 6I-3655 Manifolds.

Illustration 3. Low or high mount turbocharger: 4W-4385 and 4N-0972 Manifolds.

Illustration 4. High mount turbocharger: 2W-0483 Manifold.

7. Slide 108-3612 Spacer over each of the studs at the slots at location E.

Align the manifold sections to allow 108-3612 Spacer to slide into the slotted boles.

Position 108-3612 Spacer flush with the manifold flanges.

NOTE: The slots at location E are the 13.5 mm (0.53 in) diameter holes slotted to a width of 15.0 mm (0.59 in). Three 108-3612 Spacers are required.

8. Coat the exposed threads of the mounting studs with 5P-3931 Thread Compound.

9. On the manifold end sections, slide 9U-7224 Manifold Installation Guide over the upper mounting studs at number 2 and number 6 cylinders.

Align the manifold sections to allow 9U-7224 Manifold Installation Guide to slide into the holes in the manifold flanges.

10. All locations should use 106-1792 Taperlock Studs. Install ten 108-3612 Spacers and ten 5M-2894 Hard Washers over the remaining mounting studs.

If 6L-8562 Taperlock Stud is used at number 3 cylinder, as required with 4W-4384 and 9L-5848 Exhaust Manifolds, install nine 2S-3770 Spacers and ten 5M-2894 Hard Washers over the remaining mounting studs.

Install new 2N-2766 Locknuts on the mounting studs, except where 9U-7224 Manifold Installation Guide has been positioned.

Illustration 10. Initial tightening sequence with 9U-7224 Manifold Installation Guide installed. Numerics = sequence of INITIAL tightening (torque). X = DO NOT torque.

11. Tighten 2N-2766 Locknuts (in the sequence shown in Illustration 10) to an initial torque of:

* 38 ± 5 N·m (28 ± 4 lb ft)

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NOTICE

DO NOT use an impact tool to run the nuts down. The mounting stud threads and the nut threads will be galled causing false torque readings when tightened.

Illustration 11. Final tightening sequence with 9U-7224 Manifold Installation Guide removed. Numerics = sequence of FINISH tightening (torque).

12. Remove 9U-7224 Manifold Installation Guide and install 108-3612 Spacers, 5M-2894 Hard Washers, and 2N-2766 Locknuts over the remaining mounting studs.

Tighten remaining 2N-2766 Locknuts (in the sequence shown in Illustration 11) to a final torque of:

* 38 ± 5 N·m (28 ± 4 lb ft)

Torque Tightening Sequence

NOTE: The torque tightening sequence, in this instruction, became effective with the new design exhaust manifolds that entered production in October 1992.

Torque Tightening Specification

NOTE: The reduced torque tightening specification, in this instruction, became effective in production in February 1992 for the 3400 Engines.

Install Turbocharger

1. Coat the exposed threads of the turbocharger mounting studs with 5P-3931 Thread Compound.

2. Install the turbocharger with new mounting gaskets and new mounting nuts.

3. Install and connect the oil supply and return lines with new gaskets and O-rings.

4. Tighten the turbocharger mounting stud nuts to the torque specification shown in the Service Manual.

NOTE: DO NOT retorque the manifold or turbocharger bolts if the engine is hot.

NOTE: The 2P-2333 High Temperature Sealer, used in the exhaust manifold assembly and installation, must be allowed to cure before starting the engine. An overnight cure, if possible, is recommended.