I ran across one of these and wonder what and how it's used? It's on a site somewhere that says to use it when adjusting the valves, but it never said or showed how or when?

 

You would use this wrench to set the valve clearance. Place it in the screw slot with the nut loosened off and twist until it clicks on your feeler gauge. This is to help reduce the human feel aspect of setting valves using feeler gauges. Some guys like it just to touch others like the feeler to snap when it comes out. This eliminates that issue.

 

Ahh, that makes sense, don't know why I didn't figure that out...Thanks!

 

Ya, as long as you are the one doing every valve set, I doubt a thousandth here or there really makes a difference.

 

Yea, at least they should be set all the same. Sweet!