Crankshaft Main Bearing

MAIN BEARING HOUSING INNER DIAMETER





^ Install main bearing caps and main bearing beam without installing main bearings, and tighten main bearing cap bolts to the specified torque.
^ Measure the inner diameter of main bearing housing with bore gauge.
Standard 63.993 - 64.017 mm (2.5194 - 2.5203 inch)
^ If out of the standard, replace cylinder block and main bearing caps as assembly.

NOTE: Cylinder block cannot be replaced as single part, because it is machined together with main bearing caps.

MAIN BEARING OIL CLEARANCE
Method by Calculation
^ Install main bearings to cylinder block and main bearing caps, and tighten main bearing cap bolts with main bearing beam to the specified torque.





^ Measure the inner diameter of main bearing with bore gauge. (Bearing oil clearance) = (Main bearing inner diameter) - (Crankshaft main journal diameter)
Standard 0.035 - 0.045 mm (0.0014 - 0.0018 inch) (actual clearance)
Limit 0.065 mm (0.0026 inch)
^ If clearance exceeds the limit, select proper main bearing according to main bearing inner diameter and crankshaft main journal diameter to obtain specified bearing oil clearance.

Method of Using Plastigage
^ Remove engine oil and dust on crankshaft main journal and the surfaces of each bearing completely.
^ Cut Plastigage slightly shorter than the bearing width, and place it in crankshaft axial direction, avoiding oil holes.
^ Install main bearings to cylinder block and main bearing caps, and tighten main bearing bolts with main bearing beam to the specified torque.

CAUTION: Do not rotate crankshaft.





^ Remove main bearing caps and bearings, and using scale on Plastigage bag, measure the Plastigage width.

NOTE: The procedure when the measured value exceeds the limit is same as that described in the Method by Calculation.

CRUSH HEIGHT OF MAIN BEARING





^ When main bearing cap is removed after being tightened to the specified torque with main bearings installed, the tip end of bearing must protrude.
Standard There must be crush height.
^ If the standard is not met, replace main bearings.

Main Bearing Cap
Tighten main bearing cap bolt as follows:
Apply new engine oil to threads and seat surfaces of mounting bolts.





Tighten bolts in numerical order as shown in the figure in several different steps.
Torque 32.3 - 38.3 Nm (3.3 - 3.9 kg-m, 24 - 28 ft. lbs.)





Turn all bolts another 90 to 95 degrees clockwise [Target: 90 degrees (Angle tightening)].

CAUTION: Use angle wrench [SST: KV10112100 (BT8653-A)] to check tightening angle. Do not make judgment by visual inspection.

After installing mounting bolts, make sure that crankshaft can be rotated smoothly by hand.

MAIN BEARING CAP BOLT OUTER DIAMETER





^ Measure the outer diameters (d1, d2) at two positions as shown in the figure.
^ If reduction appears in A range, regard it as d2.
Limit (d1 - d2) 0.11 mm (0.0043 inch)
^ If it exceeds the limit (large difference in dimensions), replace main bearing cap bolt with new one.

MAIN BEARING:

MAIN BEARING

Undersize:

Undersize

Main Bearing Oil Clearance:

Main Bearing Clearance