Spark plugs for the Kizashi

[SamirD]

Using a calibrated butt dyno?

I think he was referring to the idle and fuel economy. All of us know how much extra power you can get from a plug.

[SamirD]

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?

For me, it just seemed like a waste to get rid of a perfectly good plug that a slight bend of the electrode would fix. Of course, when the center electrode was almost worn flat and the top electrode was noticeably turned down to be gapped properly, it was definitely time for new plugs.

[KuroNekko]

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):

But oil and spark plugs work very differently. Premium synthetic motor oil not only lasts longer, but gives thermal, wear, and cleanliness protection benefits over conventional oil.
Premium spark plugs have minuscule benefits other than lasting longer.
They're not really analogous.

Honestly, I don't consider coil packs or their boots as fragile, delicate items. If they can amplify and send electrical pulses and sit on a hot metal case that houses explosions, I think they can stand some tugs from a human hand once in a while.

I change the plugs on all kinds of cars and never seen a coil-on-plug that looked too fragile to be worked on once in a while. The only fragile things are old, worn-out spark plug wires like what was in my VW camper.

There is also the risk of harming the spark plug threads on the block, but that's more from installing the plugs incorrectly and/or working on a hot engine.
I work on engines cold for spark plugs and even use a dedicated rubber spark plug installer to thread the plug in until it needs to be torqued down. There are measures one can take to minimize these risks.

[murcod]

One other point I forgot to add, a lot of sites recommend replacing the coil on plug boots each time you change the spark plugs!

PS: Do some research on the advantages of thin electrode plugs vs traditional copper. There's more to it than just longer life!

[bootymac]

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.

VW/Audi coil packs fail very frequently too so perhaps some of my knowledge can be of use here.

Physical damage wasn't a factor as they're quite durable and they simply pop on and off. They failed due to large spark plug gaps (out of spec) and poor plug conditions, both of which increased the resistance to spark (and in turn, heat build up). While others were replacing coil packs annually, my factory ones lasted 13 years before one had an occasional misfire. Healthy plugs should hopefully minimize coil pack failure for us.

Another common ignition issue is the wiring for the coil packs. They can become brittle overtime and crack, causing shorts. I haven't taken a look yet, but if our wiring isn't insulated from heat, we can be proactive and wrap it in heat reflecting tape.

We can use whatever plug we want as long as we service them regularly. I highly doubt we'd notice a difference between the various types since our engine is far from a performance engine

[murcod]

Yes, large plug gaps cause the coil secondary voltage to build up to a higher level than normal, the higher voltage then can find other easier paths to ground eg. through the spark plug boot. It also puts additional heat stress on the coils. A worn spark plug electrode (eg. from using copper over Iridium) will add to the risk due to increased electrode erosion.

As I mentioned earlier, I've got a lot of experience on other Suzuki coil on plug engines (Grand Vitara/ XL-7 - I've owned one for over 6yrs.) On that forum there have been a lot of recent cases where boot failures have caused miss fires/ poor acceleration and economy. Also people have posted pictures of broken coil packs and boots. Perhaps VAG coils are built tougher?

Here are some examples:



The Kizashi coils/ boots are a slightly different design, so I hope they're stronger. I also hope the boots are replaceable like the Grand Vitara's - as that's all a lot of people have had to replace. I recently bought a spare set from the USA - the prices are horrendous over here (AUS$44 per boot and it's a 6 cylinder engine.)

[~tc~]

I was referring to the wires, not the plugs. He said if you want to use the carbon core wires, plan on replacing them annually.

As for air filters - yes, he was more concerned with airflow than filtration. He was a huge proponent of the K&N Stub Stack - calling it a "must have"

[bootymac]

As I mentioned earlier, I've got a lot of experience on other Suzuki coil on plug engines (Grand Vitara/ XL-7 - I've owned one for over 6yrs.) On that forum there have been a lot of recent cases where boot failures have caused miss fires/ poor acceleration and economy. Also people have posted pictures of broken coil packs and boots. Perhaps VAG coils are built tougher?

Here are some examples:

Well, shit.

[SamirD]

This particular coil pack looks like it was a victim of twisting at some point in its lifetime, which are a no-no for any type of spark plug wire.

I've never had to replace wires due to failure, even on my Accord with 1994 wires on it. I simply did it since I got a great deal on a set of Magnecor's.

It will be interesting to re-read the service manual for the exact procedure for plug replacement. I'm sure there's some cautions in there that most mechanics simply ignore that create failure down the road.

[KuroNekko]

Keep in mind that a XL-7 is really more a GM product than a real Suzuki. It's a GM frame and if you have a V6, it's a GM-sourced engine. I would not at all be surprised to see the Kizashi use a different coil pack from that in a V6 XL-7. Maybe even a different supplier.