1998/09/01 Caterpillar

3508 (23Z, 70Z, 1ZF),
3508 EUI (5XM, 3LS),
3508B (6PN, 4GM, 2HW),
3512 (24Z, 67Z, 3YF),
3512 EUI (6PM, 3MS),
3512B (8RM, 6WN, 4AW),
3516 (25Z, 73Z, 4XF, 5SJ),
3516 EUI (7KM, 3NS) 3516B (7RN, 6HN, 1NW) Generator Set;
3508 (96Y, 69Z),
3508 EUI (3PS),
3508B (7SM, 2BM, 1TW),
3512 (50Y, 66Z),
3512 EUI (3RS),
3512B (4TN, 7HM, 2GW),
3516 (29Z, 72Z, 4MJ, 5MJ),
3516 EUI (3SS),
3516B (8KN, 8CN, 3CW) Marine;
3508B (3DM, 3DW),
3508 EUI (3TS),
3512B (8EM, 1PW),
3512 EUI (3WS),
3516B (9AN, 2FW),
3516 EUI (3XS) Marine Auxiliary;
3508 (95Y, 68Z) 3512 (49Y, 65Z, 1LM),
3516 (27Z, 71Z) Industrial;
3508 (6TJ),
3508B (5PS),
3512 (2WK),
3512B (3ZW),
3516 (9KF) Locomotive;
3508 (97Y),
3512 (51Y),
3516 (28Z) Vehicular Engines;
G3508 (4WD, 2JF, 9TG, 9AW),
G3512 (4KC, 5JD, 7NJ, 6JW),
G3516 (3RC, 8LD, 4EK, 5PN, 8PW) Engines

SUPPLEMENT: OCTOBER 1998

Engine News SEBD9264, Article 9, Page 6, September 1998; "Recommended Lubrication And Torque Procedure For Main Bearing Cap Bolts".

The subtitle (list of applicable commercial engines) is incomplete. Add the following G3500 Engines to the list.

G3508 (4WD, 2JF, 9TG, 9AW),

G3512 (4KC, 5JD, 7NJ, 6JW)

G3516 (3RC, 8LD, 4EK, 5PN, 8PW) Engines

--------------- END SUPPLEMENT ---------------

The quality of the main bearing cap to cylinder block joint depends on the proper bolt stretch. Bolt stretch is determined mostly by the torque applied to the bolts but is also affected by the type of thread lubricant used. The only acceptable lubricant for main cap bolts is engine oil. The use of a thread lubricant on main cap bolt threads other than engine oil will lead to improper bolt stretch and possible bolt damage.

The following procedure should be used when installing main cap bolts.

Bolt Tightening Sequence 7/8

Current Cylinder Block With Inch Size Main Cap Bolts

1. Lubricate bolt threads and under head radius with engine oil before assembly. Do not use any other lubricant on the bolt threads.

2. Tighten bolts 1 through 4 in number sequence to a torque of 190 ± 14 N·m (140 ± 10 lb ft).

3. Turn bolts 1 through 4 in number sequence another 180 ± 5 degrees.

3/4

Early Cylinder Block With Inch Size Main Cap Bolts

1. Lubricate bolt threads and under head radius with engine oil before assembly. Do not use any other lubricant on the bolt threads.

2. Tighten bolts 1 through 4 in number sequence to a torque of 136 ± 14 N·m (100 ± 10 lb ft).

3. Turn bolts 1 through 4 in number sequence another 210 ± 5 degrees.

NOTE: Main bearing cap bolts are generally reusable through 60,000 hours. Do not reuse a main bearing cap bolt beyond 60,000 hours.

One way to damage a bolt at overhaul is to clean it improperly. If a bolt needs more than wiping off, clean it in a mild petroleum based solvent. Make sure the solvent has not been contaminated with water. If contaminated, the solvent will pit the bolt. Also, be sure and never clean a bolt with a chlorinated solvent. The chlorine will attack the bolt surface and leave pits. A pitted bolt will fail at low hours.

See the Guideline For Reusable Parts, SEBF8301, Inspection And Reuse Of Critical Fasteners For All Engines, for more information on reusing bolts.