Selecting Bearing Shells

GENERAL INFORMATION
Bearing shells are available in two thickness classes for standard size, 1st undersize and 2nd undersize. The two thicknesses can be combined to obtain the specified clearance. Only one shell thickness is available for 3rd and 4th undersizes. The different shells are colour-coded as follows:

Standard Size:
^ Red: Thin bearing shell giving increased clearance
^ Blue: Thicker bearing shell giving reduced clearance

1st Undersize:
^ Yellow: Thin bearing shell giving increased clearance
^ Green: Thicker bearing shell giving reduced clearance

2nd Undersize:
^ White: Thin bearing shell giving increased clearance
^ Brown: Thicker bearing shell giving reduced clearance

EXAMPLE
Try to obtain the correct clearance by fitting two thin bearing shells. If the clearance is excessive, reduce it by fitting one thin and one thick, or two thick shells. If the clearance is excessive even after two thick bearing shells have been fitted, the crankshaft must be ground down to the next undersize and the appropriate undersize bearing shells fitted. (Sizes are given in the Technical data section.)

NOTE: Crankpins and journals can be ground down one undersize (0.25 mm or 0.0098 inch) without the need for rehardening of the shaft. Grinding to a further undersize will necessitate Tenifer treatment to reharden it.