PINION-DIFFERENTIAL BEVEL 4D7537 - Caterpillar

D353 Industrial And Marine EnginesDescription of Change: A new cylinder head gasket, which has a larger fire ring, is used on the D353 Industrial and Marine Engines. The wire used in the fire ring for the new gasket is 0.117 mm (.0046") larger in diameter than the wire in the former gasket.
Because of the larger fire ring, increased torque is necessary on the cylinder head bolts/nuts to keep the same load on the gasket body. The new torque is 470 14 N m (350 10 lb ft); the former torque was 410 14 N m (300 10 lb ft).
While the load on the gasket body is the same, the load on the fire ring is increased. This added load decreases the radial movement of the cylinder liner which caused erosion between the cylinder liner and the cylinder block.
Adaptable As: The new 1W6440 Cylinder Head Gasket is a direct replacement for the former 8N7264 Cylinder Head Gasket which is canceled. Two are necessary. Use the correct procedure which follows to tighten the head bolts or nuts.
Procedure For Engines With Spacer Plates
1. Put clean oil on the bolt threads.2. Tighten bolts 1 through 20 in sequence to 307 14 N m (230 10 lb ft). See Illustration 1.
Illustration 1. Sequence to tighten bolts on engines with spacer plates.3. Again, tighten bolts 1 through 20 in sequence to 470 14 N m (350 10 lb ft).4. Tighten bolts 21 through 25 in sequence to 100 14 N m (75 10 lb ft).5. Again, tighten (hand torque only) bolts 1 through 20 in sequence to 470 14 N m (350 10 lb ft).6. Again, tighten bolts 21 through 25 in sequence to 100 14 N m (75 10 lb ft).Procedure For Engines Without Spacer Plates
1. Put clean oil on the stud threads.2. Tighten the nuts in sequence of 1 through 20 to 307 14 N m (230 10 lb ft). See Illustration 2.3. Again, tighten the nuts in the same sequence to 470 14 N m (350 10 lb ft).4. Again, tighten (hand torque only) the nuts in sequence to 470 14 N m (350 10 lb ft).Special Instruction, Form No. SEHS7990 has the new torque and sequences to tighten the nuts or bolts when the new gasket is used. The Special Instruction comes with the new gasket.
Illustration 2. Sequence to tighten nuts on engines without spacer plates.