They are a little blacker than I am used to seeing, and one looks wet to me.

How old are your coils and wires?

More Plug Reading
 

Hey All,

Since recently recovering from The Car Fever, I have decided to keep my 8...picked up a set of BHR Coils and MSD wires, (thanks lude1888). Noticed some corrosion on the end of one of the plugs. Decided to take a look. I haven't pulled the rest yet but am going to replace them all.

Things to note:

72k Miles on the car/original engine

These plugs have around 10k miles

As far as I can tell from the maintenance records (there are a lot), these are the original coils and wires.

I have been premixing with idemitsu around 6 oz per fill up.

I drive pretty spirited with regular redlines but usually operate in the 3-6k rpm range

***Found this thread searching, didn't realize it was a Series 1 thread....Mines a series 2.

Definitely looks due for a change. A little weird for 10k, you need to wind this engine out once in a while to self-clean the plugs. Changing coils is a good idea.

Yeah I thought so too, I checked again, 6500 miles on those plugs.

Yes always change plugs and wires when you change coils.

So pulled my spark plugs today.

Only about 10k miles since last time, and these are what I have got...

https://cimg9.ibsrv.net/gimg/www.rx8...547729eac7.jpg

https://cimg0.ibsrv.net/gimg/www.rx8...1ddfa73df4.jpg

Front Leading

https://cimg2.ibsrv.net/gimg/www.rx8...2fe7d50a0b.jpg

Front Trailing

https://cimg3.ibsrv.net/gimg/www.rx8...109ef83d85.jpg

Rear Leading

https://cimg4.ibsrv.net/gimg/www.rx8...0da1ac4aba.jpg

Rear Trailing

Thoughts? Only additives I have used are the Idemitsu Premix(1:200 ~ 1:250 ratio) and one bottle of STP fuel injector cleaner. Have always used 91 octane from Shell(mostly) or Petro Canada, and sometimes 94 octane from Chevron.

That looks a little crusty for 10k km. How aggressively do you drive? You may need to get it to self-cleaning temperature/pressure more often.

Actually, they are 16k km old.

I drive the car hard whenever possible.

That said, BC winter is like 95% rain and that limits my RPM to about 5k or the DSC will kick in. I also did quite a few short trips to school due to rain as well.

Also, I use the Pennzoil conventional(yellow bottles) for engine oil, if that makes a difference.

The thing that really puzzles me is the green deposit. Just what could leave green deposit behind?

Here is a link to NGK's page for reading spark plugs:

NGK Spark Plugs

Your plugs look normal to me, if a little crusty, although the one with the dark insulator looks like it has been running hot, unless that is just grease.

NGK says some green deposits are normal--especially in engines with an iron block and/or that sit awhile between runs.

Here is a link to how my plugs normally look:

https://www.rx8club.com/series-ii-te...-plugs-262810/

Yeah, I was reading the first link last night. The car has oil "leakage"(injection) and sometimes I do short trips, which I guess is what they mean by "operating duration", so I should have expected the deposit.

The black stuff is just oil. I was changing oil and filter at the same time and got a little bit on the front leading plug.

And I recall you saying that you change your spark plugs annually? I may have to follow that schedule as well.

Currently I have to wait until Tuesday to be able to run the car. Everything is good, except I snapped the hose joint on the intake tube and one of the hoses that connects to it...

Being S2s, I wonder if oil injection contributes to this.

Below is an example of mine at 25,000ishkm (the dirty one ;)), but there may be a couple of reasons it's not as crusty:
2-stroke oil injection only
track days
90% highway duty

Maybe we can run an experiment. Now that you know how they look, can you put them back in and spend an hour doing 2nd or 3rd gear pulls? Or a track day. You don't need to get to redline, just have sustained periods of full throttle high load, when you, say accelerate on an onramp in a safe and legal manner. Curious to if/how that might clean them up.

There's a cult here in Quebec who change their spark plugs every 5000km. It seems excessive, but perhaps their driving habits crust up their plugs.

http://i271.photobucket.com/albums/j...psmepxsbla.jpg

I changed them yearly, when I was tracking the car at least 12 times per year. Since I bought my Miata, I track the 8 once or twice per year, so I will change them on a mileage interval; I just haven't decided what that will be yet. I need to get the car to the track more often, but the Miata is always ready to go, since it is in track trim at all times, and the RX-8 takes several hours of work to make ready. I almost always just take the lazy option and drive the Miata. Of course, getting the 8 ready to go is a beer drinking opportunity, so I should explore the option more for that reason alone... :beer05:

Yeah, we S2 can still only use engine oil injection(no SOHN), so that could be a reason.

That said, while I don't track my car(looking into AutoX, though), I can redline it multiple times on a good day.

Right now, I am not particularly keen on going under the car again, the new spark plugs are also in there now. If Steve's S2 sees track duty and his spark plugs can develop a bit of crust over time, then I am not overly worried as mine is a spirited DD. If there are other S2 owners who can show their spark plugs here, that would also be great.

So your S2 is a track car only? No DD?

The only thing that's a bit annoying is just that I have to keep getting them from the States. For some reason, RX-8 plugs are about 4 times as expensive outside of the States. Even with the exchange rate, shipping, and duty, Mazmart's price still beats 3 Canadian prices I have checked(dealer, NAPA, clubplug.ca).

It was mostly a track car. Now, it is mostly a street car that is still track capable, assuming I want to swap the brakes and wheels. It doesn't get driven much anymore. I wish I could say I drive it once a week, but the manual transmission in Dallas traffic keeps me in my DD most of the time. I'm moving to the country in a few months. Maybe it will suit my lifestyle better there. (My house will be 20 minutes from my home track.)