Standard Procedure - Main Bearing Selection

NOTE:

There are three different possibilities for the upper main bearings and five different lower main bearings. The upper and lower bearing shells are not interchangeable.

NOTE:

Crankshaft thrust bearings are not selectable and are only available in a single thickness.

Bearing oil clearance can also be determined by using Plastigage or equivalent. Refer to ENGINE BLOCK, STANDARD PROCEDURE .

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The upper and lower main bearings are "select fit" to achieve proper oil clearances. The lower crankshaft main bearing journal diameter grade markings (1) are stamped into the nose of the crankshaft. These marks are read from left to right (clockwise), corresponding with journal number 1, 2, 3, 4, 5 and represent specific journal diameters. Refer to SPECIFICATIONS .

The lower main bearing shells are marked with a color code indicating bearing size. The bearings are available in five different sizes in order to achieve the desired oil clearance.

The chart below identifies the five lower main bearing sizes.

Bearing Marking	Size mm (in.)
0 (Yellow)	2.497 - 2.500 mm (0.0983 - 0.0984 in.)
1 (Green)	2.500 - 2.503 mm (0.0984 - 0.0985 in.)
2 (Brown)	2.503 - 2.506 mm (0.0985 - 0.0987 in.)
3 (Black)	2.506 - 2.509 mm (0.0987 - 0.0988 in.)
4 (Blue)	2.009 - 2.012 mm (0.0988 - 0.0989 in.)

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Engine block upper main bearing journal diameter grade markings (2) are stamped into the left side of the engine block. These marks are read from left to right corresponding with journal number 1, 2, 3, 4, 5 and represent specific bore diameters. Refer to SPECIFICATIONS .

Courtesy of CHRYSLER GROUP, LLC

The upper main bearing shells (1) are marked with a color code indicating bearing size. The bearings are available in three different sizes in order to achieve the desired oil clearance.

The chart below identifies the three upper main bearing sizes.

Bearing Marking	Size mm (in.)
1 (Yellow)	2.494 - 2.500 mm (0.0982 - 0.0984 in.)
2 (Brown)	2.500 - 2.506 mm (0.0984 - 0.0987 in.)
3 (Green)	2.506 - 2.512 mm (0.0987 - 0.0989 in.)