G3408C and G3412C Engines Caterpillar

Installation Procedure

Illustration 1	g00503404

Note: Ensure that the main bearings are installed so that bearing tabs (3) fit into the notch in the cylinder block and in the main bearing caps.

Note: Install the main bearings without lubricant when the check for the crankshaft main bearing clearance is made. Put clean engine oil on the crankshaft main bearings for final assembly.

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Illustration 2	g00503174

1. Install the upper halves of the main bearings in the cylinder block with Tooling (A) .

2. Install the lower bearings in the bearing cap.

Note: When the bearing clearance is checked and the engine is in an upright position or on a side position, the crankshaft must be supported against the upper halves of the main bearings. This is done in order to get a correct measurement with Tooling (B) . If the crankshaft is not supported, the weight of the crankshaft will cause an incorrect reading. If the engine is inverted it is not necessary to hold the crankshaft upward. Do not rotate the crankshaft when Tooling (B) is installed.

Note: Refer to Guideline For Reusable Parts, SEBV0544, "Engine Bearings and Crankshafts" for complete details concerning measuring of bearing clearances.

3. Use Tooling (B) to check the crankshaft main bearing clearances. Follow Steps 5 and 6 for the correct installation procedures and tightening procedures for the main bearing caps when the clearance check is performed. Refer to Disassembly and Assembly, "Bearing Clearance - Check".

   Bearing clearance (new bearings) ... 0.091 to 0.186 mm (0.0036 to 0.0073 inch)

   Maximum permissible bearing clearance (used bearings) ... 0.25 mm (0.010 inch)

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Illustration 3	g00503665

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Illustration 4	g01424367

Note: Ensure that the numbers on main bearing caps (1) match the numbers on the cylinder block. The arrows on main bearing caps (1) are toward the front of the cylinder block.

Note: Install the thrust plates with the identification "Block Side" toward the cylinder block.

4. Put Tooling (D) on bolts (4) .

5. Install main bearing caps (1) .

6. Tighten bolts (4) for main bearing caps (1) , as follows:

   1. Tighten the bolt first on the bearing tab side of the main bearing cap to a torque of 260 ± 14 N·m (190 ± 10 lb ft).

   2. Tighten the bolt opposite the bearing tab side to a torque of 260 ± 14 N·m (190 ± 10 lb ft).

   3. Put a mark on each bolt and on each main bearing cap.

   4. Tighten the bolt opposite the bearing tab side for an additional 120 ± 5 degrees (2 flats).

   5. Tighten the bolt on the bearing tab side for an additional 120 ± 5 degrees (2 flats).

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Illustration 5	g00504380

7. Use Tooling (C) to check the crankshaft end play. Ensure that Tooling (C) is against a machined surface. The end play is controlled by the thrust plates of No. 4 main bearing (center).

   Crankshaft end play (new thrust plates) ... 0.15 to 0.50 mm (0.006 to 0.020 inch)

   Maximum permissible crankshaft end play (used thrust plates) ... 0.89 mm (0.035 inch)

End By: Install the engine oil pump. Refer to Disassembly and Assembly, "Engine Oil Pump - Install".