How to Distinguish Spark Plug Materials?
4 Answers
Methods to distinguish spark plug materials: You can determine by the core in the middle of the electrode. If it is thick, it is the ordinary type; if it is thin and white in color, it is platinum; if it is thin and yellow in color, it is iridium. The spark plug is one of the important components in the automobile ignition system, which can introduce high-voltage current into the cylinder to generate an electric spark, thereby igniting the mixed air-fuel inside the cylinder. Factors affecting the performance of the spark plug include: the gap between the spark plug electrodes being too large or too small. If the gap between the spark plug electrodes is too small, the generated spark will be weak, leading to carbon deposits and subsequent leakage. If the gap between the spark plug electrodes is too large, the required breakdown voltage will be higher, making the engine harder to start, especially at high speeds where misfiring may occur.
The material of spark plugs primarily depends on the center electrode and ground electrode, which affects their performance and lifespan. Copper-core spark plugs are the most common, featuring a nickel-alloy-coated copper center electrode. They offer good conductivity but wear out quickly and are inexpensive, making them suitable for regular family cars. Platinum spark plugs are more durable, with a platinum coating on the electrodes that resists high-temperature corrosion and ensures stable ignition, resulting in smoother engine performance. These are ideal for drivers seeking cost-effectiveness and longer replacement intervals. Iridium spark plugs are currently the top-tier option, with ultra-fine iridium electrodes that produce a stronger spark and faster acceleration response, making them perfect for high-performance or modified vehicles. To distinguish them: 1) By appearance: Copper spark plugs have thicker electrodes with a dark brown hue; platinum ones are silver-white; iridium plugs are shinier and finer. 2) Check the part number: Packaging or the plug itself may indicate the material—e.g., NGK BKR5E denotes copper, while DENSO TT stands for iridium. I always recommend drivers choose based on their driving habits—for example, frequent long-distance drivers should opt for platinum or iridium plugs to minimize issues.
The material of spark plugs can be judged from daily usage experience. My most common DIY method is to check the feel during replacement and the engine's response. Copper ones feel harder to the touch, with thicker electrodes and a bronze-like color. When installed, ignition is less stable, sometimes causing cold starts to shake. They suit older cars but have a short lifespan, needing replacement every 50,000 to 60,000 kilometers. Platinum ones have a shiny silver coating on the electrodes, making installation smoother. They provide faster ignition, quieter engine operation, and a lighter throttle feel. I find them much more reliable for my own car, lasting around 80,000 kilometers. Iridium ones have ultra-fine, sparkling electrodes, feel lightweight, and deliver strong acceleration with no stuttering at high RPMs—perfect for speed enthusiasts, though they're a bit pricey. If unsure about the material, check online recommendations for your car model or measure the electrode gap at a shop. Smaller gaps usually indicate premium materials. Don’t just rely on the brand—different series use different materials. For example, some Bosch spark plugs are copper-platinum hybrids. Regularly replacing spark plugs can improve fuel efficiency, a tip I often share with friends.
Distinguishing spark plug materials is quite simple, mainly by observing the electrode part. Copper spark plugs have thicker and darker-colored electrodes, which are common but wear out faster. Platinum spark plugs feature a silver coating on the electrodes, offering better durability. Iridium spark plugs have the thinnest and shiniest electrodes, delivering superior performance. When installing, check these characteristics to choose the appropriate material for more stable engine operation.
