Quote:
Well... they're called "feeler" gauges, not "jam-it" gauges; I figure if you're forcing it in at all that you're not getting an accurate measurement. 
Yes but if the gauge has a slight angle to the clearance your checking it will "feel" like the gap is correct... As Wise suggested using the next bigger gauge and getting moderate tension isn't a bad method.. For valves I use a Go/NoGo gauge, for rod clearance where seeing the proper angle is easy I use a standard gauge & expect a light pull...
"The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."
| 
