Crankshaft Main Bearings

NOTE: There are three sizes of standard main bearings, each size is marked with a 3, 4 or 5. Replacement main bearings should have the same number as the number stamped on the cylinder block. See Fig 1 and STANDARD MAIN BEARING SIZES table.

Measure crankshaft runout at center journal. If runout exceeds .004" (.10 mm), replace crankshaft. Inspect all journals for wear or scoring. Out-of-round or taper limit is .0004" (.010 mm). If crankshaft is worn excessively, grind journals for undersize bearings.

Fig 1: Cylinder Block Main Bearing Size Identification

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

STANDARD MAIN BEARING SIZES

Application		In. (mm)
Cylinder Block No. 3
Bore Size		2.5198-2.5201 (64.004-64.010)
Journal Diameter		2.3616-2.3622 (59.984-60.000)
Bearing Thickness		.0783-.0784 (1.988-1.992)
Cylinder Block No. 4
Bore Size		2.5201-2.5203 (64.010-64.016)
Journal Diameter		2.3616-2.3622 (59.984-60.000)
Bearing Thickness		.0784-.0786 (1.992-1.996)
Cylinder Block No. 5
Bore Size		2.5203-2.5205 (64.016-64.022)
Journal Diameter		2.3616-2.3622 (59.984-60.000)
Bearing Thickness		.0786-.0787 (1.996-2.000)
Cylinder Block No. .25 O/S
Bore Size		2.5198-2.5205 (64.004-64.022)
Journal Diameter		2.3504-2.3508 (59.701-59.711)
Bearing Thickness		.0837-.0841 (2.126-2.136)

Measure bearing clearances using Plastigage method. Observe correct tightening sequence. See Fig 2. If clearance exceeds specification, grind journals for undersize bearings.
Standard main bearing clearance is .0010-.0022" (.025-.055 mm). Maximum main bearing clearance is .0031" (.078 mm). Main bearings are available in .25 mm undersize. Main journal finish diameter for undersize bearings is 2.3504-2.3508" (59.701-59.711 mm).

Fig 2: Main Bearing Tightening Sequence