2001/07/01 Caterpillar

Engine:

All 3600

All C280

All G3600

Engine News SEBD9672, 13 October 2010, "New Tightening Procedure for Connecting Rod Bolts in 3600, G3600, and C280 Engines". Disregard the referenced article. Use this updated tightening procedure.

Description of Change: This article is a clarification of the tightening procedure for the connecting rod bolts in the above engines.

Reuse Information for the Connecting Rod Bolts

Inspect connecting rod bolts at each service of the connecting rod bearings. There should be no fretting on the shank or on the knurled area or annular ring of the connecting rod bolt. Ensure that the connecting rod bolt meets the guidelines for reusable parts. Do not reuse the connecting rod nuts.

Illustration 1	g00775406
Maximum dimension (X) for the connecting rod bolt

Do not reuse a connecting rod bolt if dimension (X) is more than 329 mm (12.953 inch).

Do not torque a connecting rod bolt more than five times. The maximum usage of five times does not necessarily mean that the bolt can always be used five times. The bolt must meet the criteria that is explained above.

Tightening Procedure for Connecting Rod Bolts

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Illustration 2	g02282533
4W-8344 Retainer

1. Before you install the bolts into the connecting rod, clean the 4W-8344 Retainers. Clean the seats for the retainers on the connecting rod, and clean the bolt heads. The parts must be clean and dry.

2. Inspect each bolt for debris, for nicks, and for damage from shipping.

3. Assemble the retainers and the bolts into the connecting rod as shown in Illustration 2.

4. After the bolts have been installed, lubricate the threads of the bolts, the threads of the nuts, and the seats for the nuts on the connecting rod with a heavy coat of 334-0519 Grease (MOLYLUBE, ANTI-SEIZE).

   Note: This torque procedure was developed with 334-0519 Grease (MOLYLUBE, ANTI-SEIZE). The use of any other lubricant may result in an incorrect torque value and in subsequent failure of the connecting rod bolt.

5. Turn all four nuts by hand until the nuts contact the face of the cap. No resistance should be felt that would indicate thread damage or debris in the joint. Thread the nuts by hand in order to identify problems with the threads. If the nuts and/or bolts cannot be threaded by hand, the nuts and/or bolts must be replaced. Ensure that the threaded end of the bolt is flush with the end of the nut. This check ensures that the bolt head is properly seated on the retainer. Do not use an impact wrench to install the nuts up to the face of the cap.

Note: Understanding the locations of the bolts and using the exact tightening sequence is critical. Holes (1) and (4) are smaller than holes (2) and (3). The bolts in holes (1) and (4) are used to index the rod cap to the correct location on the rod. The bolts in holes (1) and (4) must be tightened first.

Note: Holes (1) and (2) are on the same side of the connecting rod as the bearing tab slot. Hole (1) is on the side next to the serial number pad. The cylinder number is on the bearing tab side of the connecting rod.

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Illustration 3	g02282153
Holes for the connecting rod bolts (5) Bearing tab slot (6) Serial number pad

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Illustration 4	g00756010
Sequence for tightening the connecting rod bolts

6. Tighten nuts (1), (4), (2), and (3) in sequence.

   Torque ... 105 ± 15 N·m (75 ± 10 lb ft)

7. Tighten nuts (1), (4), (2), and (3) in sequence.

   Torque ... 340 ± 15 N·m (250 ± 11 lb ft)

8. Without loosening the nuts, tighten the nuts for the second time in the following order: nut (2), nut (3), nut (1) and nut (4) .

   Torque ... 340 ± 15 N·m (250 ± 11 lb ft)

9. Tighten the nuts again in the following order: nut (1), nut (4), nut (2) and nut (3) .

   Turn the nuts in a clockwise direction. ... 180 ± 5 degrees

Adaptable To: This new torque procedure is adaptable to all 3600 Gas Engines, to all 3600 Diesel Engines, and to all C280 Engines. This procedure is not for 3618 Diesel Engines.