Anderson Ed wrote:

Well Folks, I pulled the  NGKB8EV spark plugs this week end on my 13B.
Talk about spark plug devastation - the lead and trail spark plugs on
rotor #2 (furtherest from crank pulley end) were destroyed.  Plugs for
rotor #1 showed some wear with the lead plug having the begining of a
small ball on the center electrode, but otherwise looked OK.  These plug
have 15hrs flying time on them.

The lead plug for rotor #2 had the center eroded down and the side
electrode eroded back until there was a 3/16" gap. The side electode
also had a ball of metal on its eroded end.   The ceramic cone around
the center electrode was cracked and one side was missing.  The trail
plug center electrode was eroded 1/8" and its ceramic cone was also
cracked and one side missing.

Clearly, either the ignition over advance or the leaning has elevated
rotor combustion temps beyond the capacity of the plugs to handle.  I
hate to think what I may have done to the apex and side seals.

I stuck the stock plugs back in and fire it up.  It still stumbled a bit
on start up but quickly smoothed out and the engine ran smooth and
steady at all speeds.  Power does not seem to be down as I get the same
static engine rpm at full throttle (5000 rpm)as previously, so maybe I
did not deep six the engine.

Someone mentioned the possibility of lead having and adverse effect on
platinum electrode plugs, but there was nothing on the spark plug box of
the  NGKB8EV to indicate, so I presume they are not platinum.

Paul, I measured the distance from the engine block to the face of the
propeller flange of my Ross Area PSRU and it measures 14 1/2 inches.

I also whipped up a fiberglass snorkel opening this weekend for the oil
cooler inlet, but it rained all day Sunday, so did not get to test it
out.  Will test it out this coming weekend.

Ed Anderson

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