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Owner's manual says 100,000 spark plugs...
BUT they don't say they need to be re-gapped
about every 30,000 miles...
Big gasoline waste if they're not...
quote:The need to gap iridium plugs is up for debate. Some camps say that since the wire is so fine, you shouldn't gap or you run the risk of breaking the electrode. Other camps say you should, using a special tool. My particular car has a spec'd range of gap and the NGK Iridium IX plugs come in within that range so there is no need to gap them. I would trust the "100,000 tune-up" very little. I think that after that long in the engine, there is always that risk of them seizing. If anything, loosen, remove, and re-torque every 30-50K and you should be OK. I changed my iridium plugs at 50K and wouldn't have wanted to run them much longer based on what they looked like. (No, no fouling or damage or anthing like that, just the electrode appearance).
Originally posted by BUBBA0420: If they recommend 100,000 on the plugs those plugs are Iridium tipped and are not supposed to be re-gapped.
quote:OEM plugs are mostly platinum and not iridium. Ir has 1/2 the resistance of platinum. I've heard that shouldn't matter but i don't believe it. And it's only one element down so it should wear about the same. I replaced the stock plugs on our BMW 530i at about 80k. They were 4-prong NGK platinums and the center electrode was done. Regapping them helped a bit (very tough with 4 electrodes), but replacing them with large gap Ir plugs really helped. Smoother idle, better throttle response, less raw fuel smell during cold starts. I didn't keep track of the mpg's very well as it's not my car but I believe they went up about 1 mpg. 15 to 16mpg, yoohoo. this site has some Ir info: www.sparkplugs.com/faqmain.asp
Originally posted by BUBBA0420: If they recommend 100,000 on the plugs those plugs are Iridium tipped and are not supposed to be re-gapped.
quote:I imagine more than one material property is considered for plug tip material. - melting point - oxidation resistance - electrical resistance - cost, fabricability Pt and Ir have very migh melting points. There are many other elements with even higher melting points - Mo, Cr, Si, C - but they would quickly oxidize. Spark plug choice, per se, doesn't increase gas mileage. Otherwise, the manufacturers would simply specify better plugs to achieve an extra 1 mpg (which is a lot in today's competitive market!). New spark plugs will only increase gas mileage if the old ones weren't igniting the mixture.... and that happens when the old plugs are dirty or misgapped. Premium plugs are offered in the market simply to extend the length of service of the plug in the engine before replacement.
Originally posted by gtx510: Ir has 1/2 the resistance of platinum. I've heard that shouldn't matter but i don't believe it. And it's only one element down so it should wear about the same. I replaced the stock plugs on our BMW 530i at about 80k.... I didn't keep track of the mpg's very well as it's not my car but I believe they went up about 1 mpg. 15 to 16mpg, yoohoo.
quote:You don't want to put antiseize on Ford 5.4 engine made between 00 and 04, the ones with only 4 threads in the head for the spark plugs. They have a bad history of blowing out.
Originally posted by Master ACiD: most if not all plugs today come right out of the box with a plating on the threads that acts as an anti-seize.
quote:I don't see how antiseize would help the plugs blow out. The blow-out problem is from the threads in the cylinder head getting buggered up by the carbon that collects on the exposed threads. When you go to remove the plugs, the built-up carbon deforms the threads, leaving the next set of plugs with less purchase on the threads, thus rendering the next set of plugs vulnerable to popping off. Go ahead and use antiseize on the threads.
Originally posted by Schmoe: You don't want to put antiseize on Ford 5.4 engine made between 00 and 04, the ones with only 4 threads in the head for the spark plugs. They have a bad history of blowing out.