"mikem" wrote in message
ups.com...
(10MegOhm), while the other six ranged from 1.4K to about 7K.

I expected all of these to be the same resistance, but was surprised at
the variablity plug to plug. I am puzzled at the two that read open.
They were not misfiring before removal. What's going on?

No problem. The ones that read open had a sub-thousandth crack on the
resistor and would arc across the crack before going to the two orders of
magnitude larger crack called a spark gap.



btw- I also measured 12 brand-new RHM40Es; 4 of 12 were open end to
end???

QC strikes again. They only "bomb test" the suckers. If there is a minute
crack between the resistor and the plug, they figure that the plug gap will
predominate in the sparking mechanisms. With the obvious comment that a
spark in oxygen rich atmosphere will wear down a contact MUCH further than
in the combustion chamber. Thus a failed plug in a few hundred hours. I'd
suggest you reject the opens. Unless we all continue to do so, plug
manufacturers will be getting away with this slop.

Jim