Posted by Jack Cain on October 18, 2000 at 17:06:44:
There a pretty good article in the November Hot Rod about engine fasteners (bolts,nuts,studs). There are a couple of charts (ASTM and SAE) that give the physical properties of the most used automotive engine fasteners (Grade 0 through Grade 8, some other ASTM standards).
I knew that the use of oil or grease on a bolt or nut would reduce the friction but I didn't think that it would reduce the amount of torque that you would apply by as much as 45% (Fel Pro C-5), 40% (common grease)