Nissan Armada 2025-2026 Service and Repair Manual: Main Bearing

Main Bearing

DESCRIPTION

• The identification grade stamped on each part is the grade for the dimension measured in new condition. This grade cannot apply to reused parts.

• For reused or repaired parts, measure the dimension accurately. Determine the grade by comparing the measurement with the values of each selection table.

• For details of the measurement method of each part, the reuse standards and the selection method of the selective fitting parts, refer to the text.

WHEN NEW CYLINDER BLOCK AND CRANKSHAFT ARE USED

“MAIN BEARING SELECTION TABLE” rows correspond to bearing housing grade on rear side of cylinder block.

	: Bearing housing grade No. 1
	: Bearing housing grade No. 2
	: Bearing housing grade No. 3
	: Bearing housing grade No. 4
	: Engine front

“MAIN BEARING SELECTION TABLE” columns correspond to journal diameter grade on front side of crankshaft.

	: Journal diameter grade No. 1
	: Journal diameter grade No. 2
	: Journal diameter grade No. 3
	: Journal diameter grade No. 4
	: Pin diameter grade No. 1
	: Pin diameter grade No. 2
	: Pin diameter grade No. 3
	: Pin diameter grade No. 4
	: Pin diameter grade No. 5
	: Pin diameter grade No. 6
	: Identification code

Select main bearing grade at the point where selected row and column meet in “MAIN BEARING SELECTION TABLE”.

Apply sign at crossing in above step 3 to “MAIN BEARING GRADE TABLE”.

NOTE:

• “MAIN BEARING GRADE TABLE” applies to all journals.

• Service parts are available as a set of both upper and lower.

WHEN CYLINDER BLOCK AND CRANKSHAFT ARE REUSED

Measure cylinder block main bearing housing inner diameter and crankshaft main journal diameter. Refer to Inspection.

Correspond the measured dimension in “Cylinder block main bearing housing inner diameter” row of “MAIN BEARING SELECTION TABLE”.

Correspond the measured dimension in “Crankshaft main journal diameter” column of “MAIN BEARING SELECTION TABLE”.

Follow step 3 and later in “When New Cylinder Block and Crankshaft are Used”.

MAIN BEARING SELECTION TABLE

MAIN BEARING GRADE TABLE (ALL JOURNALS)

UNDERSIZE BEARING USAGE GUIDE

• When the specified main bearing oil clearance is not obtained with standard size main bearings, use underside (US) bearing.

• When using undersize (US) bearing, measure the main bearing inner diameter with bearing installed, and grind main journal so that the main bearing oil clearance satisfies the standard.

  CAUTION:

  In grinding crankshaft main journal to use undersize bearings, keep the fillet R [1.5 - 1.7 mm (0.059 - 0.067 in)].