> > Had a little talk with Klause about spark plugs.

 > He said if they are fouling and the gap is not increasing
 > they are too cold. Go to hotter plugs.
 > Nippon Denso, if you can find them, are better.
 >
 > He also says 50 hours is typical for auto plugs in
 > aircraft. He should know. He has over 100 MSD "Plasma"
 > systems in the field.
 >
 > Paul Lamar

Robin Ream wrote:

 Is there an easy answer for us non-engineers as to why the auto plugs have
 such a short life in aircraft applications?

 Robin

IMHO in Klauses case he is putting a lot more electrical energy through
them than the magneto provides. He is also useing a waste spark
system that does not help. In our case lead fouling seems to be
the limiting factor. Once we have that fixed with hotter plugs
perhaps they may last longer with the stock inductive system.

Paul Lamar

    Its a catch 22, I have tried hotter plugs but the electrodes erode
away very fast and I ran into detonation.
  The best plug I have found so far is NGK BUR9EQP in both holes, also
found the platinums lasted longer.
  Ken Welter

I also think the shorter life is due to the increased average  power the
engine is generating compared to its use in a car.

Here are a few charts from Heisler's book on the subject.

Paul Lamar
 
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