Read My RX-8 spark plugs

[bedwards6954]

hey everyone, I am changing the spark plugs in my 8, I heard that brown is okay, and that black is bad, so what if you get both, here is a quick picture

<a href="http://www.flickr.com/photos/36804699@N02/3630863597/" title="100_2660 by supafastprobe, on Flickr"><img src="http://farm4.static.flickr.com/3655/3630863597_fd6fb865a8.jpg" width="500" height="375" alt="100_2660" /></a>
is the back rotor

<a href="http://www.flickr.com/photos/36804699@N02/3630862679/" title="100_2659 by supafastprobe, on Flickr"><img src="http://farm4.static.flickr.com/3604/3630862679_8da4a2ceb0.jpg" width="500" height="375" alt="100_2659" /></a>
is front rotor

does that look good?

seems to have some kind of carbon build up too, I did sign up for rx8club but I have to wait til they activate my account, and I am inpatient

I recently got the car, and from what I gathered these plugs where installed sometime in 06

 

[DMRH]

Carbon build up is a sign of too much putting around in traffic. Low rpm & rotary engines can be an issue if the plugs are too hot for the application.

These plugs appear well worn & its obvioulsy time for a change.

Dont buy new from Mazda as they will rip you. Get them on-line from a place such as sparkplugs.com

Plugs are usually good for 20,000km despite what a dealer may tell you.

REgards

 

[bedwards6954]

thanks, I did some searching and got the plugs from amazon for 16 or so a piece. I got them all change leading and trailing.

I noticed however that the trailing on the front rotor was black, and the ignition wire was loose. There seem to be some kind of rusted metal on the inside of the plug itself, I cleaned it out best I could, and crimped the metal a little tighter so it would hold on to the plug.

the end of the plug that connects to the ignition wire, was a little green too....

 

[SpooledupRacing]

yeah deff need to bring these engines into the power band more often.. to much low rpm driving as stated will create LOTS of carbon buildup which will be the end of that engine.

 

[bedwards6954]

looking at getting ignition wires, anybody try magnecors offerings?

 

[DMRH]

looking at getting ignition wires, anybody try magnecors offerings?

Installed a set of "Magnacores" in my RX-8 when I had it. Noticed it reved smoother & idled better. Adding to that, I did do a "Grounding kit" on the engine at the same time so the gains may have been a combination of the two mods.

REgards

 

[Nerva]

just curious, do you replace the wires usually when you guys replace the plugs? and how long does it usually take to replace the wires and plugs

 

[solidtrance]

From: RX-8 Basic Maintenance Information (suggested interval)

OEM plugs are recommended unless you are FI, and maybe even then. You will need a 13/16 plug wrench, some extensions and either a universal adapter or wobble extensions to remove and replace the plugs. Be sure to use some anti-seize grease when you install the new plugs.

OEM Leading NKG PN: RE7C-L
OEM Trailing NKG PN: RE9B-T

OEM Coils are recommended unless you can either fabricate a bracket to hold Yukon Style coils or buy a premade kit (such as the one made by BHR). You will need a 10mm socket with a 6 10 inch extension to replace them. Additionally you will need to remove the whole intake all the way back to the throttle body.

OEM PN: 18-100B-N3H1-9U, N3H1-18-100B-9U

Youre ignition wires should be checked when you replace anything in the ignition system, and replaced when they appear to be worn or the connection with the coil or plug is not very solid. The engine vibrates a lot even under low to medium load. These connections are vital and can cause major problems if they are not solid.

OEM PN: N3H1-18-140B
Magnacor 8mm - W49435
Magnacor 10mm - W45435
Mazdatrix 10-800-Red (Available in Red, Yellow, Blue and Purple)
MSD 8.5mm ??
MSD 10mm ??
Ultra PN: 14R-1003 (good-win), 11516 (racing beat)

 

[bedwards6954]

I would replace the wires

 

[mrslysly]

That white ash is a sign of not getting hot enough long enough. The rotaries LOVE to be flogged, unlike the american muscle. Every time you drive the car you should do a few shifts where you let it redline before shifting. After the engine is all nice and warm.

The easiest way to tell when to replace the plug wires is when their impedance varies too much. Get a cheap digital volt/ohm meter from radioshack and measure the resistance of each wire. If they are all fairly close in values, go ahead and keep running them. If they vary greatly, or even one varies, definitely swap the plug wires out. Another thing to consider is the early (2004-2006) rx8s had weak coils and after many heat soak cycles would wear out so that after 4.5krpm they wouldn't deliver enough juice to produce the proper spark. If you feel adventurous enough, pull the coils off and look at the bottom of them. If they have white almost chalky marks on the bottom, then scrap them and get new ones. Or goto the extreme and put the yukon ls1 coils on!

 

[mrslysly]

I drove my 8 very hard, she saw lots of high R time. I replaced plugs before they reached 10k miles. They literally wore out. But I have heard lots of other stories, all be it anecdotal, about vastly improved idle and throttle response just by changing out plugs that had 15k+ miles.