Due to advancements in spark plug designs, precious metal spark plugs are becoming increasingly common as original equipment in newly manufactured vehicles.WHY YOU SHOULD ALWAYS FIT THE RECOMMENDED SPARK PLUG!
Due to advancements in spark plug designs, precious metal spark plugs are becoming increasingly common as original equipment in newly manufactured vehicles.
In the past, consumers have had the choice of using the standard OE part, or a more expensive precious metal plug for enhanced performance and life gains. Now that these high performance and higher cost spark plugs are standard in some vehicles, consumers are asking the question "Can I substitute the precious metal plug for a similar or equivalent standard plug? "
Even though many plugs with similar part numbers may look the same, each part number has its own characteristics, with some changes not physically visible. These differences are imperative to the operation of the engine and straying from the recommended plug can result in some loss of performance (best case) or severe engine damage (worst case).
Following is a list of possible design characteristics and problems that can result if the recommended plug is not used;
| Design Characteristics | Possible Problems |
| Modified Ground Electrode | Ground electrodes can have a number of modifications to increase their heat dissipation, and vibration resistance. An inferior substitute may not have these features and may cause damage if the ground electrode comes loose or melts at the weld. |
| Ignitability | Precious metal plugs have a higher ignitability than standard plugs. Substituting to another plug may result in poor performance. |
| Required Voltage | Precious metal plugs require less voltage to spark due to the fine centre electrode. Changing to a standard plug will put additional strain on the ignition system. This may also inhibit cold starts. |
| Internal Resistance | The internal resistance in some platinum and iridium plugs differ from the standard resistor plugs. If you do not have the required noise suppression for your vehicle, damage to on board electronics may occur. |
| Double Precious Metal Plug | NGK double platinum and iridium-platinum plugs have a platinum chip on their ground electrode. There can be differences in the quantity of platinum and the shape of the chip. For vehicles with dual polarity ignition, sparking occurs in both directions (centre to ground and ground to centre). If standard plugs are used then plug life will be dramatically reduced. |
Designs can consist of one or more of the characteristics listed above. These characteristics are requested by vehicle manufacturers as each engine design is unique and requires changes in plugs to suit. For peace of mind, ALWAYS ensure you use a plug recommended to meet the OE specification. This will avoid any damage and ensure peak performance of your vehicle.
If you have any queries please contact your nearest NGK office.