Service Limits & General Specifications

INNER DIAMETER OF MAIN BEARING HOUSING





Install the lower cylinder block with the main bearings removed and tighten the mounting bolts to the specified torque. Refer to ASSEMBLY.
^ Using a bore gauge, measure the inner diameter of the main bearing housing. Refer to CYLINDER BLOCK.
^ If out of the standard, replace the cylinder block and lower cylinder block assembly.

NOTE: These components cannot be replaced as a single unit because they were processed together.

OIL CLEARANCE OF MAIN BEARING
Method of Measurement
^ Install the main bearings to the cylinder block and lower cylinder block. Measure the main bearing inner diameter with the lower cylinder block bolts tightened to the specified torque. (Oil clearance) = (Inner diameter of main bearing) - (Outer diameter of crankshaft journal)
Standard:
No. 1, 3, and 5 journals: 0.012 - 0.022 mm (0.0005 - 0.0009 inch)
No. 2 and 4 journals: 0.018 - 0.028 mm (0.0007 - 0.0011 inch)
Limit: 0.1 mm (0.004 inch)
^ If the measured value exceeds the limit, select main bearings referring to the main bearing inner diameter and crankshaft journal outer diameter, so that the oil clearance satisfies the standard. Refer to HOW TO SELECT A MAIN BEARING.

Method of Using Plastigage





Remove oil and dust on the crankshaft journal and the surfaces of each bearing completely.
^ Cut the Plastigage slightly shorter than the bearing width, and place it in crankshaft axial direction, avoiding oil holes. Tighten the main bearing bolts to the specified torque.

CAUTION: Never rotate the crankshaft.

^ Remove the bearing cap and bearings, and using the scale on the 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 the 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





Undersize





Bearing Oil Clearance