Usage:
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
The quality of the cylinder head 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 head bolts is engine oil. The use of a thread lubricant on cylinder head bolt threads other than engine oil will lead to improper bolt stretch and possible bolt or thread damage. The proper head tightening procedures are outlined below.
Bolt Tightening Sequence
The tightening procedure for cylinder head bolts used on a high torque, shot-peened diesel head is as follows:
Typical High Torque, Shot-peened Diesel Head
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 all bolts to 30 ± 5 N·m (22 ± 4 lb ft).
3. Tighten bolts 1 through 8 in number sequence to a torque of 400 ± 35 N·m (295 ± 26 lb ft).
4. Tighten bolts 1 through 8 in number sequence to a torque of 575 ± 20 N·m (425 ± 15 lb ft).
The tightening procedure for cylinder head bolts used on a nonshot-peened diesel head is as follows:
Typical Low Torque, Gas Or Diesel Head (B) Area with no shot-peening.
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 all bolts to 30 ± 5 N·m (22 ± 4 lb ft).
3. Tighten bolts 1 through 8 in number sequence to a torque of 270 ± 35 N·m (200 ± 26 lb ft).
4. Tighten bolts 1 through 8 in number sequence to a torque of 450 ± 20 N·m (330 ± 15 lb ft).
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.
NOTE: Loosening and retorquing a cylinder head bolt does not limit the number of times the cylinder head bolt can be reused. A bolt should not be reused if there is pitting in the fillet under the bolt head.
See the Guidelines For Reusable Parts, SEBF8301, Inspection And Reuse Of Critical Fasteners For All Engines, for more information on reusing bolts.