This document describes how to modify the Created date field in the Issue Navigator to include the time. By default, the column view of the field hard-codes the rendering format to the locale specific "Day" format.
Edit the file
JIRA_INSTALL_DIR/atlassian-jira/WEB-INF/classes/templates/jira/issue/field/created-columnview.vm to always use the extended formatDMYHMS rather than formatDMY.
For example, the following macro fragment should be changed: