What are the differences in spark plug materials?
4 Answers
Based on the different materials of spark plugs, they can be categorized into: standard copper core, yttrium, platinum, iridium, and platinum-iridium alloy spark plugs. Below is relevant information about spark plugs: 1. The service life of these types of spark plugs varies, and so does the corresponding replacement mileage. 2. Generally, under normal usage conditions, standard copper core spark plugs have a service life of 30,000 kilometers, while precious metal spark plugs last between 60,000 to 90,000 kilometers. 3. Typically, entry-level vehicles come equipped with resistor spark plugs as standard, whereas luxury and mid-to-high-end models are mostly fitted with iridium spark plugs as original equipment.
A few days ago, I helped my neighbor check his old car, and the topic of spark plug materials was quite interesting. The ordinary nickel alloy ones are like the basic version, costing about ten or twenty yuan each, and they need to be replaced every 20,000 to 30,000 kilometers. Mechanics often call them 'disposable items.' Platinum spark plugs are much more durable, with a platinum coating on the center electrode, easily lasting 50,000 to 60,000 kilometers, and each one costs around fifty to sixty yuan. The most impressive are the iridium spark plugs—their tips are as fine as a strand of hair, providing exceptionally sharp ignition, and the engine revs up noticeably faster. Although they cost over a hundred yuan each, they can last more than 80,000 kilometers. In my opinion, if you frequently drive on highways, iridium spark plugs are worth the investment, while platinum ones offer the best value for grocery-getter cars.
We had a car in the shop that wouldn't start, and upon disassembly, we found the spark plug electrodes had melted. Nickel alloy's melting point is just over a thousand degrees—pretty risky for turbocharged cars. We fixed it by switching to iridium spark plugs, which have a melting point of 2,400 degrees. Actually, electrode shape matters too—standard plugs have thick, flat tips, while premium ones like NGK feature sharpened tips for easier spark generation. Once a customer bought the wrong heat range to save money, causing rough cold starts. Remember: high-compression engines need cold-type spark plugs.
Those who are into car modifications understand the mystery of electrode gap. Iridium spark plugs can have their gap adjusted up to 1.1mm, increasing ignition energy by 20-30%. Naturally aspirated cars modified this way show noticeably better throttle response. However, this must be paired with high-voltage ignition coils. The material also affects heat conduction speed - iridium conducts heat over five times better than nickel alloy. I've seen fellow car enthusiasts using wrong heat range plugs, ending up with combustion chamber carbon deposits looking like black sesame paste. If you frequently drive mountain roads, you'll need precious metal spark plugs to withstand the high temperatures.
