ISO 13778:2017 specifies the selective assembly of bearings (in accordance with ISO 3548‑1).
The bearing diametral clearance is determined by the housing diameter, journal diameter and the wall thickness of the two half bearings. Typically, these components will have a total tolerance "stack up" of 50 µm to 60 µm. Current engine development and in particular, the desire for improved engine refinement, has provided a need to decrease the clearance range due to the tolerance "stack up". This document suggests various schemes of selective assembly to achieve such ranges.