Spark plugs are the subject of much controversy. In comparison to internal
combustion engines and their management systems, spark plugs have hardly
been developed. Malfunctions still occur, but they are not as noticeable
anymore mainly because of improved ambient conditions. At least one of the
three most important spark plug properties efficiency, durability,
heatrange has to be sacrificed in order to increase or emphasize one
of these characteristics.
For high performance or racing applications, an efficient spark plug is needed.
Such a spark plug operates optimally only within a narrow heatrange, without
any consideration for durability. This is not a good spark plug for street
automobiles, as a wide heatrange is essential to assure good drivability
under all temperature conditions. Heatrange latitude of standard low cost
spark plugs for passenger cars has improved, but with major trade-offs. They
are designed to offer a wide heatrange only, without any consideration for
efficiency. The ignition system has to compensate for low spark plug efficiency
and wide spark plug gap caused by wear.
Original equipment spark plugs offer a wide heatrange and high durability
to increase spark plug change intervals. These are the least efficient spark
plugs. In order to reduce wear, erosion resistant materials and suppressor
resistors are used, considerably sacrificing spark plug efficiency. The correct
relationship between efficiency, durability and heatrange is important and
has to be considered over the entire life of the spark plug. A functional
combination of these properties is possible, it is only a matter of technology
and materials used.
When reading spark plug advertisements, one can get the impression that small
diameter center electrodes, uniquely shaped electrodes or built-in resistors
are the best. Think again. A RESISTOR is exactly what the word implies. When
the spark crosses the point of resistance much of the spark energy is lost.
A resistor is like an electronic obstacle and could be the cause for a weak
spark. Due to manufacturing tolerances and lack of quality control, even
non-resistor spark plugs often have a resistance of 10, 100 or even 1000
Ohms. Always check spark plugs for resistance before use.
What about electrode shape? Spark plug manufacturers will tell you that a
small diameter center electrode makes it easier for the spark to jump the
electrode gap. This is true, but what they are not saying is that such a
spark is also weaker, since it takes a lower voltage to jump the gap. A spark
jumps the electrode gap when the voltage at the electrodes reaches the ionization
point, since the ionization point, (voltage needed to jump the gap), is lower
when a small diameter center electrode is utilized, spark voltage is also
lower. Exactly what a performance orientated consumer doesn't want.
|Properties of Materials
for Spark Plug Electrodes
|W/(m·K) = Energy per meter and Kelvin
(1kcal/(m·h·grd) = 1.163 W/(m·K)
MS/m = Mega Siemens per meter (1S m/mm2 = 1MS/m), (1S = 1/3)
Nology Silver are designed for modern high performance engines and
are the only spark plugs that optimal incorporate all desired properties. The most important decision when building
spark plugs is what materials to use. Not the electrode shape. The more than
80 year old original design is still the most successful and widely used.
Silver is the best electrical and thermal conductor of any metal,
and therefore the best material for the center electrode. In managing the
ever changing combustion chamber temperatures, caused by different engine
and load conditions, silver is unsurpassed. To prevent plug fouling, optimum
operating temperature is reached shortly after start up, yet under full throttle,
when things really start to get hot, heat is dissipated rapidly. Silver provides
the widest heatrange latitude. As the best electrical conductor, silver assures
that the spark encounters the least resistance and virtually no spark energy
is lost. Unlike conventional electrode materials, silver delivers the most
powerful spark possible and therefore guarantees combustion initiation. The
large diameter silver center electrode increases spark
carrying ability and with it spark power. Silver is extremely
resistant to erosion, guaranteeing a virtually unchanged electrode gap
for the life of the spark plug. This greatly extends change intervals.
Nology Silver is the most efficient, durable and thermally
adaptable spark plug available and delivers the most
If it is a racing plug you are looking for, or a dependable and efficient
spark plug for everyday street use, Nology Silver is the one for
Copyright © 1994 –
Nology Engineering, Inc.