Cool Tracy,
If you run a standard Mazda plug the floating secondary

coil won't

hurt

you. The problem that was

found was that the fine wire electrode would take on a

mushroom

shape.

It was believed that the

combination of engine heat and electrical load caused it.

The center

wire on the platinum plugs is

softer. the Mazda style with the two or four sidewires and

standard

center electrode won't give

problems. I don't have extensive dyno rotary experience so

I will

bow to

those who have used

advanced timing. The exhaust flames when the secondary

coils failed

on

our RX-3 sedan racer were

spectacular however!  Bill Jepson

Jean Fouche wrote:

What sparkplugs are you guys using for aviation purposes? THe

standard

spec

Mazda plugs?

Jean Fouche

Stock RX-7 plugs NGK brand (BUR 7EQ lead, BUR 8EQ trail)  has

worked well

for me.  I get around 250 hrs on auto fuel,  100 or less when I

burn 100LL

avgas.  Ed can give a better idea on 100% avgas use, I use a

combination of

both but mostly auto fuel.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

        R.E. Plugs. Plugs either give up or accumulate matter depending
on
the polarity of the firing voltage. On the ground electrode of a standard
positive firing plug you would never notice it. On the center of a
negative firing plug you would find the buildup of metal. Over and under
spec
capacitors in point systems will Pit and Mound on the oppisite sides of
the points because of the same conditions, Virg

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