jguerdat

I still don't see how you can count on having any particular spark plug automatically line up. Even if Honda did tap the holes specifically, how would you get all the manufacturers into line making sure their threads matched with the gap? If I were a plug manufacturer, it'd be simpler to assemble the parts however they happen to align rather than setting the threads and then assembling the internals specifically. Possible but not likely...

Gernby

[QUOTE]Originally posted by jguerdat
[B]I still don't see how you can count on having any particular spark plug automatically line up.

Chazmo

I agree... For the plug manufacturer, there would be no difficulty making all the threads screw threads the same on each plug. The trick would be making the tolerances for the crush washer exact enough to always make each plug orient the same way at a given torque.

(not that any of this matters )