Hi Howard,
probably a dumb question, but here goes. My engine came with nord locks as well,,,, but. Someone must have been trying to save a buck because when I looked closer, I only had a half a nord lock under each socket head bolt. These washers require two pieces to work properly, with the "saw tooth" teeth against eash other. I have never heard of nordlocks loosening up if installed right, unless someting else in the assembly is crushing (like a gasket)

Fasteners properly torqued hold themselves in place by stretching between the heads and tapped holes. The nordlock principle simly holds that stretch of the metal in check.

Just a thought, as I have said before I certainly don't profess to know everything.

Mike