So I'm reading posts from another list I'm on and I see the following
write-up. I'm convinced. Well actually I was convinced before reading
this.
Ron Fenelon wrote:
When I first started working at Ford in 1965, I was a "dyed in the wool"
Champion Spark Plug guy. A couple of years later, I had the opportunity
to visit the Fostoria, OH plant where we made Autolite spark plugs.
Once I saw the difference in the manufacturing process and the sealing
method vs. what Champion does, never again did I use anything but a
Autolite/Motorcraft spark plugs. On the GM cars that I have owned in
the past, I always used AC spark Plugs, because they were made the same
way as the Autolite/Motorcraft's were made.
The principal difference is how the center electrode/porcelain insulator
is sealed to the steel outer body. In Champion plugs, the outer body is
zinc plated, and they stuff a powdered form of the center insulator
between the body and the fired center insulator, and then roll
over/crimp the upper portion of the steel body. Very easy to allow
combustion pressures/gases to make a leakage path in this powder
material. In fact, I asked TV Tommy Ivo, at the Milan, Mi Drag Way, why
he had changed from Champions to Autolites, in the early 70"s, and he
replied too many center electrode/porcelain bodies blowing right out of
the threaded bodies on his AA Fuel Hemi powered Dragster.
The Autolite/Motorcrafts and AC plugs have two copper o-rings installed
between the center electrode/porcelain bodies, top and bottom, and then
the top of the body is rolled over/crimped, and then the plug passes
into an Induction Heater where the center portion of the plug is heated
up by a ring in the center of the steel body until it glows red, about
1600 degress F, all while the crimp is held under 2500 psi pressure, and
then the Induction heater coil is turned off, and plug cools under this
2500 psi pressure. So the center electrode assembly is firmly gripped
by the outer body, and I don't remember anyone saying they ever had any
leakage problems with plugs made that way. That heating process is the
reason Autolite/Motorcraft and AC plug metal bodies are not plated.
They may be painted, like the marine plugs are, but never plated. It
would boil off in the Induction Heating/Crimping process.
Make better way to seal the center electrode assemblies, and make long
life spark plugs.
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