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Expensive spark plugs

What’s the deal with platinum ultra super duper (expensive) spark plugs versus standard plugs? In my mind, it either creates a spark and ignition, or it doesn’t.

They last 2-3X (platinum & iridium) as long as regular (copper) plugs.
Even if they cost 4X as much they still save on the labor cost of plug changes over the long run.
They reduce pollution by keeping the cylinders firing properly on the 50% (my estimate) of cars that get lax maintenance.

Yep, longer lasting, but no difference in engine performance if you change each type at the appropriate interval. And folks often have problems when switching from factory specified plugs to sooper-dooper fancy plugs. I stick with the brand and model that came with the car.

The only time you should use them.

. They don’t make a standard plug for you vehicle. My wifes Lexus plugs only come as Iridium…which are more expensive then platinum…but last even longer.

. The plugs are a royal pain to replace…again as with my wifes Lexus. The front three are easy…the back three are a royal pain.

Plug changes have luckily for me and the cars I’ve owned always been relatively easy to do, so I’ve never seen a reasoning to spend a lot on some 4 tipped platinum ultra crazy, adds 50 horsepower!, type of plugs. haha. But yes, original spec is very important, especially on fords in my experience.

Actually the best plugs for performance are you standard nickle tip plug. If the platinum or iridium or multi-tip plugs added even .1% in performance…then every race car in existence would be using them…and they aren’t.

NGK or Denso iridiums for my Insight are $12 a pop, and it has 8 of 'em (choke)!

Sure I paid $8.50 cents each for oem plugs, done at 85k miles, money well spent. Sure I was shocked at the price, used to $1.50 cent plugs for my 71 nova, but it is a wash in the long run.

The sparkplugs with the trick electrodes are not only no good but can in some instances cause damage. Use only sparkplugs recommended as OEM replacement plugs in your vehicle.

Depending on the year of your vehicle, your OEM spark plugs will either have come with copper-core, platinum, or iridium electrodes. The first has really been obsolete for decades. Platinum electrodes last far longer and keep a good gap far longer. Irridium is even 8X harder, and these erode far slower than even platinum. In a clean-running modern engine they can last over 100,000 miles… but I am not recommending going that long without changing them… although the car manufacturers do. They can get stuck in the holes after that long.

Re: the question of them either creating spark or not creating spark, it isn’t quite that simple. Flame propagation in the cylinders, how the flame “grows” if you’ll allow me poetic license, is crutial to complete fuel combustion and effectiveness of the engine in turning as much of the released energy as possible into torque at the crankshaft. High-falutin’ sparkplugs mught have pretty pictures on their ads, but they’re note necessarily compatible with the cylinder design, and improper flame propagation can adversely affect engine operation, leading to excess emissions, carbon buildup, and poor mileage. And sparkplug of the incorrect temperature range can damage the engine by allowing the cylinder to get too hot or allowing carbon buildup.

I’ve even heard of fancy-dandy plugs not fitting properly and causing mechanical damage. Standard plugs “seat” (seal themselves into the chamber) in one of two ways, either with a tapered (conical) shoulder that seats to a tapered hole, or with a flat shoulder and a compressible metal gasket. The dimensions including the taper angle must be correct for proper seating. And if the fancy plug’s body isn’t the correct length, you can end up with physical damage or carbon deposition on the lower threads in your spark plug hole or on the plug body, both of which can become problems in the future.

I won’t even bother getting into sparkplug temperature ranges. Just use the correct plugs and you can ignore my entire dissertation.

I hope this helps.

Haha, no that’s good info, thanks. I did just spend something like 1.50-2.00 each on the basic old spark plugs for my 1950 cad.

I think the advent of the “long life” spark plugs has a lot to do with spark plugs breaking or stripping out the spark plug holes. I just replace spark plugs with the OEM type when I feel the engine missing slightly. If it doesn’t fix the problem I go on from there. I still have a new set of spark plugs though in any event and that can’t hurt a thing.

You may be right. The center electrode may be “long life”, but the plug body and the heads are still the same. Maybe someday some genius will think of putting steel inserts into the sparkplug holes at the manufacturer. Hmmmmm… I wonder if they’d pay me for that idea???

Denso and NGK have an antiseize coating plated on the threads.

I doubt they’d pay you TSM. If it made them money…some guy having nothing to do with it would get a bonus, and they’d offer you a hand shake.

I worked in a big Bakery when I was young. They always stressed that if an employee came up with an idea they would share the savings. A lady ran the machine that stamped the date and price on the little tabs that closed the bread bags. She saw that between each spot on the print tape…there was enough room for two stampings that were missed. She suggested that they gear the machine down so there was just a small gap between printings on the tape. The company did just that and they cut their need for tape by over 60%…and they went thru a case per shift.
They gave the woman a gift card for $50 to a local store…while the company saved thousands per year. I think that they should have given her, what they predicted they would save in a year.
Once they pulled that nobody tried to find savings for the company anymore.


I’ve seen comments that high-tech super-duper plugs with extra prongs at the tip can cause high HC emissions problems and are best avoided. The plugs I have always used on my 20+ year old Corolla are the exact NGK part number what the owner’s manual says to use, cost about $2 each, and readily available. It only takes me about 15 minutes to change out all four plugs in my driveway, so if I have to do that every 15K, it’s not a problem.

Plugs, they look like they are more simple than they actually are. They must enter the cylinder the precise number of mm’s the engine designer specifies, even 2 mm off and there could be big problems. And have the appropriate materials and dimensions so that their thermal design causes the plug to reach the designed operating temperature. And no part of the plug should extend into the cylinder that gets coated by combustion products that could prevent removing the plug. Otherwise the cylinder head threads could get damaged when removing them. My advice is to use the exact part number the car manufacturer recommends, apply anti-seize to the threads, tighten them to the specified torque, and do it all again according to the maintenance schedule in the owner’s manual.

I agree with George

Except for one thing . . .

When working on a Ford 3 valve engine with the mile long plugs, I think it’s wise to consider installing Champion 1-piece plugs, instead of the original design, which may break the next time you’re removing them. Which might be in another few years, depending on vehicle usage

@db4690 - what do you mean by ‘1-piece plugs’? How are they different than the stock plugs?

All spark plugs for stock road cars are manufactured basically the same. The attached link provides a pretty good description. The variations are in the materials used, the quality and consistency of the plug manufacture, the accuracy maintained by he manufacturer, and the quality of the treatments such as platings used. My experience with Champion sparkplugs has been spotty. They seem not to maintain accuracy to the engine manufacturers’ specifications or consistency in the sparkplug quality. I use them in my small engines, where the combustion pressures are small and there’s lots of leeway for dimensional slop, but I’d never use them in my car.

Some years back the Feds started mandating spark plug warranty under a 24k miles/2 years policy. A normal copper core plug has a much greater chance of misfiring in that first 24k miles as compared to a platinum or iridium plug so ergo; the car makers did not want to face the prospect of countless millions in necessary or imagined spark plug changes on their dime.

The multi-electrode plugs are not necessarily a bad thing. Bosch came out with those things 30 years ago and I’ve installed a ton of them in various cars (mostly Euro) with no problems.
I think some of the bad press may be due to someone throwing plugs like that into an engine which does not call for them and when problems surface the blame goes to the plug.

I tried a pair of Bosch 4-prong plugs in one of my Harleys once and was not impressed. A few days later out they came to be replaced with Champions.
Champions seem to be ok on air cools but after a lot of grief with them on customer cars I swore them off decades ago. Too many out of the box were no good from the start or failing within a 100 miles.

That was the experience I too had with Champions years back.

Re: the multi electrode plugs, I understand that some are making their way onto some OEM applications. In those cases they’re OEM plugs and I have faith in their use. I’m uncomfortable with using them in an application that doesn’t call for them. But, as I’ve said many times, I’m not much of a risk taker.