Crankshaft & Main Bearings Service: Notes

1. Ensure main bearing caps are numbered for location. Loosen main bearing cap bolts in 3 steps and in reverse order of tightening sequence. See Fig 2.
2. Cylinder block main bearing journal bore size is indicated by a number, located on cylinder block oil pan rail See Fig 1. Ensure cylinder block main bearing journal bore is within specification. See CYLINDER BLOCK SPECIFICATIONS  table.
   Fig 1: Identifying Crankshaft Main Bearings

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3. Crankshaft main bearing journal size is also indicated by a number, located on crankshaft counterweight. See Fig 1. Ensure main bearing journal is within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS table.
4. If main bearing number is unreadable, add number on crankshaft counterweight and number on cylinder block rail to determine proper size main bearing to be used. See corresponding number in CRANKSHAFT MAIN BEARING SELECTION  table.
   CRANKSHAFT MAIN BEARING SELECTION
   
   

   Bearing Number	Bearing Thickness In. (mm)
   1	.0783-.0784 (1.988-1.991)
   2	.0784-.0785 (1.992-1.994)
   3	.0785-.0786 (1.994-1.996)
   4	.0787-.0788 (1.998-2.000)
   5	.0788-.0789 (2.000-2.003)
   O/S	.0086-.0840 (2.123-2.133)

5. Install bearing with the oil hole in the engine block. Main bearings are available in .010" (.25 mm) undersize. Tighten main bearing caps to specification in sequence. See Fig 2 and TORQUE SPECIFICATIONS. Ensure crankshaft rotates smoothly.

NOTE: Install main bearings with oil hole in cylinder block.

Fig 2: Tightening Crankshaft Main Bearing Caps In Sequence

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002