3408C, 3412C and 3412D High Performance Marine Engines Caterpillar

3408B, 3408C, 3412, and 3412C Engines

Illustration 1	g01018411
Index mark for torque-turn process

(1) Connecting rod nut

Use the following procedure for torquing the connecting rod nuts:

1. Use new engine oil to lubricate the bolt threads and the seating faces between the cap and the nut before assembly.

2. Torque the connecting rod nuts.

   Torque for nuts ... 82 ± 8 N·m (60.0 ± 6.0 lb ft)

Note: Use a paint stick to place an index mark on each of the rod cap nuts. Use the index mark as a reference in order to torque the nuts for an additional angle.

3. Tighten the connecting rod nuts for an additional angle.

   (A) Torque-turn angle ... 120° ± 5°

Note: The connecting rods should be installed in the engine so that the chamfered edge around the bore for the crank journal is facing the thrust surface of the crankshaft (fillet of the crankshaft pin). The opposite side of the connecting rods will mate together on the crankshaft pin.

Illustration 2	g01018441

(2) Connecting rod

(B) Inside diameter of the connecting rod for the piston pin bearing. ... 55.436 ± 0.013 mm (2.1825 ± 0.0005 inch) (C) Distance between the center of the bore for the piston pin bearing and the center of the bore for the crankshaft journal ... 261.62 ± 0.05 mm (10.300 ± 0.002 inch) (D) Inside diameter of the connecting rod for the crankshaft journal after the connecting rod bearing has been installed and the nuts have been torqued. ... 103.500 ± 0.013 mm (4.0748 ± 0.0005 inch)

Illustration 3	g01018846

(3) Piston pin bearing

Outside diameter of the piston pin bearing before installation into the connecting rod. ... 55.512 ± 0.013 mm (2.1855 ± 0.0005 inch)

Apply heat to the connecting rod prior to installation of the piston pin bearing. Do not use a torch to heat the connecting rod.

Heat the connecting rod for a maximum length (E) during the installation of the piston pin bearing. ... 89 mm (3.5 inch)

Maximum temperature for heating of connecting rod ... 175 to 260 °C (350 to 500 °F)

The bearing joint must be located within area (F) along the horizontal centerline of the piston pin bore. (G) Maximum angle from the horizontal centerline ... ± 5°

The bore of piston pin bearing must be machined after installation into the connecting rod. (H) Bore diameter of the piston pin bearing after machining ... 50.830 ± 0.008 mm (2.0012 ± 0.0003 inch)

Diameter of new piston pin ... 50.795 ± 0.005 mm (1.9998 ± 0.0002 inch)

3412D Engines

Illustration 4	g01018368
Tightening sequence, and index mark for torque-turn process

(1) (2) (3) (4) Rod cap bolts

Use the following procedure for torquing the rod cap bolts:

Note: The connecting rods should be installed in the engine so that the part number of the forging for the rod assembly is facing the connecting rod that is on the same crankshaft pin. The opposite side of the connecting rods will face the thrust surface of the crankshaft journal.

1. Prior to assembly, lubricate the threads of the rod cap bolts and the seating face of the bolt heads with engine oil.

2. Finger tighten all of the rod cap bolts.

3. Torque bolts (1) and (3) .

   Torque for rod cap bolts ... 70 ± 4 N·m (50 ± 3 lb ft)

4. Torque bolts (2) and (4) .

   Torque for rod cap bolts ... 70 ± 4 N·m (50 ± 3 lb ft)

Note: Use a paint stick to place an index mark on each of the rod cap bolts. Use the index mark as a reference in order to torque the bolts for an additional angle.

5. Tighten bolts (2) and (4) for an additional angle.

   (A) Torque-turn angle ... 60° ± 5

6. Torque bolts (1) and (3) again.

   Torque for rod cap bolts ... 70 ± 4 N·m (50 ± 3 lb ft)

7. Tighten bolts (1) and (3) for an additional angle.

   (A) Torque-turn angle ... 60° ± 5

Illustration 5	g01018366

(5) Connecting rod

(B) Inside diameter of the connecting rod for the piston pin bearing. ... 64.592 ± 0.013 mm (2.5430 ± 0.0005 inch) (C) Distance between the center of the bore for the piston pin bearing and the center of the bore for the crankshaft journal ... 274.91 ± 0.01 mm (10.823 ± 0.001 inch) (D) Inside diameter of the connecting rod for the crankshaft journal after the connecting rod bearing has been installed and the bolts have been torqued. ... 103.500 ± 0.013 mm (4.0748 ± 0.0005 inch)

Illustration 6	g01018369

(6) Piston pin bearing

Outside diameter of the piston pin bearing before installation into the connecting rod. ... 64.717 ± 0.013 mm (2.5479 ± 0.0005 inch)

Apply heat to the connecting rod prior to installation of the piston pin bearing. Do not use a torch to heat the connecting rod.

Heat the connecting rod for a maximum length (E) during the installation of the piston pin bearing. ... 95 mm (3.7 inch)

Maximum temperature for heating of connecting rod ... 175 to 260 °C (350 to 500 °F)

The bearing joint must be located within area (F) along the horizontal centerline of the piston pin bore. (G) Maximum angle from the horizontal centerline ... ± 5°

The bore of piston pin bearing must be machined after installation into the connecting rod. (H) Bore diameter of the piston pin bearing after machining ... 60.035 ± 0.008 mm (2.3636 ± 0.0003 inch)

Diameter of piston pin ... 59.975 ± 0.005 mm (2.3612 ± 0.0002 inch)

Illustration 7	g01026026

(7) Piston cooling jet

Tighten the bolt for the piston cooling jet to the following torque. ... 25 ± 6 N·m (18 ± 4 lb ft)