If we are using Tracy’s Fuel/Ignition Controller (which
fires both Leading and Trailing Plugs at the same time), why is it
necessary to have two different heat ranges of plugs?
The stock Mazda 13B engine from 1986 to
1992 calls for NGK BUR7EQ in the leading plug and BUR9EQ in the trailing
plug. I assume that the different
heat range is because the stock engine has the two plugs firing at a different
time. It is understandable that if
the trailing plug fires later, then the mixture has already heated up and that plug
needs to be colder. However, if
both plugs fire at the same time, it seems to me that they should both be of
the same heat range, whatever one you eventually decide on.
I have found that my trailing plugs (NGK BUR9EQ)
foul quickly at low RPMs (idle up to 3,000), while the leading plugs (NGK
BUR7EQ) do not. Since I am using Tracy’s controller,
I am thinking of running the hotter plug (BUR7EQ) in both leading and trailing
positions. Or maybe I should
compromise and run BUR8EQ all around.
Does anyone have experience with the
platinum version of these plugs (BUR*EQP)?
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Wednesday, November 22, 2006
7:50 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Spark
Plug Fouling and Temperature
Its interesting, we I use 100LL I usually get 25
hours on a set of plugs. I wonder what factors might make the difference
between your time interval and mine - "Plugs Up"?. I have
not run across any chart that indicated anything other than a plug digit which
indicated a "hotter" or a "colder version". I think I
may try hotter plugs and see if they make any difference.
----- Original Message -----
Sent: Wednesday,
November 22, 2006 8:26 PM
Subject: [FlyRotary]
Spark Plug Fouling and Temperature
Ed, thanks for that article.
I installed the hotter plugs, BUR6EQ leading and BUR8EQ trailing a month or so
ago.
I guess I'll have to start burning 100LL to see if it fixes the fouling
problem.
I usually only burn it when I'm travelling and have no other choice, but don't
have any trips planned soon.
For me, it only takes 4 hours of continuous 100LL use to get SAG and fouled
leading plugs on the next takeoff.
Is there any data anywhere that might tell us what temperature BUR6EQ, 7EQ,
8EQ, and 9EQ plugs operate at in an RX-7?
Perry
http://www.ductedfan.com
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