Funny thing,
 I was just installing a new set of spark plugs and noticed that
 there is a set of installation pictures on the stock NGT spark
 plug..  the last picture is a big red X through a picture of an
 airplane.  Specifically, we should apparently not use these spark
 plugs with motor gliders or ultralights.  So I think regular
 experimental airplanes should be OK.  :-)

 --
 David Leonard

 Turbo Rotary RV-6 N4VY
 http://N4VY.RotaryRoster.net
 http://RotaryRoster.net

 What is that some web sites say?  "Things our lawyers make us say."

 I wager this is something the legal department invented to head off a
 class of lawsuits.
 sdorr

 Do not forget about DESIGNED DUTY CYCLE. Automotive spark plugs are
designed
with a small % duty cycle. This means they are OK to the max power for
short
periods of time. AC use is a lot higher duty cycle. That is also why plugs
for
a race car are usually colder heat range than for street. I would expect
Dave
uses colder plugs than a car would use. Continuous hiway use also mandates
a
cooler plug.
 Plugs for certified engines are also subject to fitting into the certified
arena. If you drop an AC plug, you throw it over your shoulder. For
automotive, you pick it up and dust it off. Worst case is you gap it. Also
certified has money put away in the event of the legal beagles becoming
involved.

Dale Davies


What heat range NGKs?

Lynn E. Hanover


Lynn,
I use the -9P in both lead trail 'cause I cant find any 10s or 11s without
going to the race plugs... Which I would probably get from racing beat.
But still not sure if that is the best decision or not.