Use new bolts and tighten in the following stages:
1)Tighten to 25 Nm
2)Further tighten 60 degrees
3)Further tighten 60 degrees
4)Further tighten 30 degrees
5)Run engine for 15 minutes
6)Further tighten 30 degrees
7)Further tighten 15 degrees.
John
May 2009