Spark plugs for the Kizashi

[~tc~]

I LOL at people replacing plugs instead of just regapping them.

[KuroNekko]

Using a calibrated butt dyno?

Indeed. I mean, when you drive your car everyday for at least 40 miles like I do, you will know how your engine runs. When something changes, I notice. Heck, call me crazy, but I can feel the difference with clean, fresh oil versus dirty, old oil in how the engine runs. Even non-car people claim this. The "butt dyno" is a real phenomenon. Why do you think so many people claim so-and-so spark plug gave them "Moar Power!"? It's because they can actually feel the difference. The difference, however, is more likely due to using new plugs vs. old ones than previous brand/type vs. current brand/type. You still feel the difference. I sure do, however, it's more a restoration of peak power, not an increase.

Before I sold my old Mazda, I changed the plugs from old IX's to new IX's. I noticed a performance restoration. When the dealer guys who sold me the Kizashi test drove my Mazda when negotiating a trade-in, they slipped that it "was the best trade-in car with over 100,000 miles they'd ever driven". Maintenance like swapping the plugs was the key. They still low-balled me in typical douchey dealership fashion so I sold it privately later.

This is why I ran copper core plugs on my (heavily modified) GTI. The frequent change intervals ensured that I constantly had fresh plugs for optimal performance. It also allowed me to examine the plugs more frequently to monitor for any potential problems. The price difference in the long run was insignificant and it gave me an excuse to wrench in the garage

This sentiment is quite common among tuners so I'm not surprised. Some really actually prefer simple copper plugs like NGK V-Powers because they know condition matters more than type. Some even claim that the bigger copper center electrode is better for their ignition purposes than a thin iridium, platinum, or whateverium center electrode. They merely swap out plugs more regularly. I have also read that platinum plugs are incompatible with Nitrous Oxide and therefore coppers are preferred.

I LOL at people replacing plugs instead of just regapping them.

Technically, you're not supposed gap or regap iridium plugs. Manufacturers claim they A) spark efficiently enough to negate gapping and B) their thinner center electrodes are brittle and may be damaged from gapping.
Some people still gap iridiums out of the box and then install them. I've done it before and experienced absolutely no benefit in doing so so I stopped bothering. That being said, gapping copper plugs is the norm. Copper plugs are so cheap that regapping them to extend lifespan is almost a waste of time. If you are going to take the trouble to pull them out, might as well spend the $10 to replace them all. That's more my philosophy.

In the end, people have different uses, approaches, and beliefs so there isn't a real proper regiment with spark plugs. It's all dependent on your use, plug type, and whether you like changing them occasionally or forgetting about them for 100,000 miles at a time.

[murcod]

The factory manual actually says to clean/ regap the nickel plugs, but replace the Iridium.

[KuroNekko]

The factory manual actually says to clean/ regap the nickel plugs, but replace the Iridium.

Sounds right as by "copper" we are actually talking about nickel-alloy plugs which are the "standard" plugs. Iridiums should be replaced because they have more brittle center electrodes and by the time you need to deal with them, you ought to just replace them.
My argument is that with "copper"/nickel-alloy plugs only costing around $2.50 each, why not just replace them at the intervals when one would re-gap and clean? I don't have a manual handy so I'm not sure what the nickel-alloy plug maintenance intervals are but I can't imagine it's often.
I spend around the same on lunch in downtown DC everyday as a set of 4 copper plugs would cost me. Replacing them is indeed unnecessary, but it's not like it's going to set me back much.

[murcod]

You risk damaging the coil packs and spark plug boots every time you unnecessarily remove/ refit them. I think I've mentioned it previously, but spark plug boot failures (misfires) are becoming common on Grand Vitaras/ XL-7's that are approaching the 10yr + age mark. They use a virtually identical coil on plug set up. The fault is very hard to diagnose and the boots are significantly more expensive than even the Laser Iridium plugs to replace. I'd imagine Kizashi spark plug boots would be dearer again? Edit: Just checked Rockauto and the plug boots aren't listed separately to the coil assembly- so ~US$115 per coil/ plug assembly.

Spark plugs - nickel NGK V groove - you're looking at $4.16 ea .... so just under half the price of the Laser Iridium for 1/3 to just under 1/2 the life (depending on Normal or Severe operating conditions.)

PS: I posted the maintenance intervals for both plug types earlier today.....

[KuroNekko]

You risk damaging the coil packs and spark plug boots every time you unnecessarily remove/ refit them. I think I've mentioned it previously, but spark plug boot failures (misfires) are becoming common on Grand Vitaras/ XL-7's that are approaching the 10yr + age mark. They use a virtually identical coil on plug set up. The fault is very hard to diagnose and the boots are significantly more expensive than even the Laser Iridium plugs to replace. I'd imagine Kizashi spark plug boots would be dearer again? Edit: Just checked Rockauto and the plug boots aren't listed separately to the coil assembly- so ~US$115 per coil/ plug assembly.

Spark plugs - nickel NGK V groove - you're looking at $4.16 ea .... so just under half the price of the Laser Iridium for 1/3 to just under 1/2 the life (depending on Normal or Severe operating conditions.)

PS: I posted the maintenance intervals for both plug types earlier today.....

You risk damage of threading out the oil drain plug hole at every oil change. Yes, you may risk damage by removing a coil pack, but it's not a good reason to avoid using traditional plugs. I even use dielectric grease and anti-seize when changing plugs. The dielectric grease helps with removing the plug from the boot. NGK now claims anti-seize is no longer necessary due to a special coating they apply to the metal of their threads. Okay...
Also, I think coil-on-plugs are a lot more durable than traditional spark plug wires which got brittle over time but not at the boot as much as at the wires. Every time they tore, it was at the wire after years of enduring engine heat. I'd pull at the boot, but even the stress of the wire bending too much tore them if they were old. Not that I cared as they were to be replaced anyways. In comparison, coil packs don't even have wires that can break off like that.

[~tc~]

Actually, carbon core plug wires would breakdown just over time and be arcing inside the wire - I read a book called "making power" or something like that, and it was kind of like myth busters for engines. He was absolutely adamant about two things - K&N filters and metal core plug wires.

[KuroNekko]

Actually, carbon core plug wires would breakdown just over time and be arcing inside the wire - I read a book called "making power" or something like that, and it was kind of like myth busters for engines. He was absolutely adamant about two things - K&N filters and metal core plug wires.

What's a "carbon core" plug? All these NGK plugs that have iridium, platinum, etc. center electrodes actually have a copper core. It's these rare metals that are used at the tip where the electrodes arc.

What was his position on K&N (I'm assuming air) filters? That they're good? I've owned a few in the past and wasn't impressed enough to get one in the Kizashi. They risk oil and particle ingestion. For offroaders or high performance engines, yes, they are worth it. For the regular engine seeking longevity, nope. Many tests have proved these aftermarket foam, cloth, etc. filters don't filter as well as OEM filters. They sacrifice particle filtration for air flow.

[murcod]

You risk damage of threading out the oil drain plug hole at every oil change. Yes, you may risk damage by removing a coil pack, but it's not a good reason to avoid using traditional plugs. I even use dielectric grease and anti-seize when changing plugs. The dielectric grease helps with removing the plug from the boot. NGK now claims anti-seize is no longer necessary due to a special coating they apply to the metal of their threads. Okay...
Also, I think coil-on-plugs are a lot more durable than traditional spark plug wires which got brittle over time but not at the boot as much as at the wires. Every time they tore, it was at the wire after years of enduring engine heat. I'd pull at the boot, but even the stress of the wire bending too much tore them if they were old. Not that I cared as they were to be replaced anyways. In comparison, coil packs don't even have wires that can break off like that.

Another case of each to their own! I wouldn't be using the cheapest oil in my engine and changing it every 1000 miles either.

PS: The coil pack boots are very much like the the old spark plug leads - only shorter and a lot less likely to fail because they are fixed firmly in place and don't move (unless you fiddle with them unnecessarily )

Here's is an XL-7 coil pack boot (fitted between the coil and spark plug):


And here is a Kizashi coil/ boot assembly - it's hard to say if the boot could be replaced separately? Hopefully they can and aftermarket suppliers will start making them in the future- otherwise things could get very expensive 10yrs down the track.

[SamirD]

I also consider inline 4 cylinders the simplest engine to change plugs on.

This is primarily why I would check the plug gap every 10k miles or so on all my Japanese cars. It's just so easy to check, adjust and reinstall in less than 10m. Plus, you can tell a lot about the combustion process by looking at a plug. NGK once upon a time had a guide to help you with this on their web site.

I haven't done anything to the Kizashi yet as this is my first car with coil packs, but I'm assuming it will be fairly similar once I get used to the torques and tooling.