Join Date: Jun 2005
Location: Conyers/McDonough, GA
Are they all iridium spark plugs???
100k mile spark plugs have iridium center electrode and a platinum button on the nickle ground electrode.
50k mile spark plugs have iridium center electrode and a nickle ground electrode.
Years ago NGK had problems with counterfeit spark plugs. I do not see it on their web site now.
Waste Spark Ignitions
Like most automotive systems, the ignition system has undergone many changes. One example is the Distributorless Ignition System, or “DIS” for short. This system was first introduced in the 1980s. The distributor, cap and rotor in a conventional system were replaced by coil packs. The new DIS system proved to be more reliable and required less maintenance.
The earliest DIS featured a bank of coils; one coil for every two cylinders. Each pair of coils would provide power to two spark plugs. Each of the two paired coils would fire the paired spark plugs simultaneously, one on the compression stroke and the other on the exhaust stroke. Since one plug is fired on the exhaust stroke, serving no real purpose, the system was known as a “waste spark system.” This style of ignition has negative and positive polarity sides to the coil; meaning the spark plug also has positive or negative polarity.
It is important to know that in a waste spark ignition, both the center firing electrode and ground electrode will see gap erosion. In plugs with a positive polarity, most wear will occur at the center-firing electrode. Plugs with negative polarity will experience more wear at the ground electrode. As a result of this, vehicles equipped with waste spark ignitions often use double precious metal spark plugs, such as the OE Iridium® or OE Platinum®. These dual precious metal plugs feature either iridium or platinum on the center-firing electrode and platinum at the ground electrode. Because these electrode materials are denser, gap erosion is reduced, allowing a longer service interval. Since these materials are denser, this will reduce gap erosion, thus leading to a much longer service interval. The use of nickel-alloy or single precious metal spark plugs in vehicles equipped with waste spark ignitions will result in more aggressive gap erosion and shorter spark plug life.
2005 1300c Red, Mustang seat, HK 2.5 straights. Leds for safety-front & back. 194,184 VTX miles