So I've been using my BHR ignition for some 50K miles now, and decided it was time to change my spark plugs. The trailing plugs have been in the car since mile 0, and have some 58k on them. The leading plugs were replaced when I installed the BHR ignition.

The car runs fine, even better now that I've put in new plugs, but I'm wondering why the trailing plugs are half black like it was running rich, and half tan like a worn plug should look like. Is this natural for RX-8's?

What are my plugs telling me RX-8 club? Help me! you're my only hope!

 

Typical for worn plugs.....just more so because of the number of miles you put on them.
Congrats on getting so many miles on a set & a half of plugs.

If I were to read the plugs correctly I'd guess they're saying "Please change me at 20K miles maximum"

 

It was still running fine too!

I bet it has something to do with that BHR ignition. Nice strong spark.

 

It says you are running pig rich.
You do not redline enough and you drive in town too much.
The spark was hot enough to keep the engine running but you can see pig rich fuel build up even with a hot spark.

 

Guilty.

Can't do much about the fuel maps though. They're stock and I'm not taking a tuner to them.

 

I can't rightly tell to be honest. I've got nothing to measure it with. The electrode is recessed in the plug so my little autozone gap measuring disk doesn't fit. The center electrode looks a bit rounded off, and the pin that sticks out is still square, but might have worn a bit thinner.

I'm not supposed to regap the new ones, am i? The little drawing on the box says not to take a screwdriver to it, so i suspected that meant not to regap them.

 

its just the mark of the way the flame front travels. Thats all.
Plugs probably could be reused if you clean them with an ultrasonic cleaner.

 

They look normal. I too would love to know what the gap was. In early rotary days we would get to 4K miles(monthly for me) and hate the throttle response and have to clean(lead deposits) and adj them. We went through all kinds of spark plugs and rarely saw the same one twice. The development to get over 50K now is excellent! OEM-NGK are the best value for stock tune....I think the Rotary has pushed the spark plug to where now most people sell their car before they change the plugs....

 

I will bring the plugs by my local autodrone and see if they can measure the gap on them. I'm sure they must have a tool that will work. You'll have to measure the gap on some new OEM plugs yourself, I'm not pulling them out now.

I've seen really worn down plugs before and these, while covered in deposits, don't look terribly worn. Just dirty. The leading ones look much like i had expected, having done them before with low mileage. Tan crud all over. I had never done the trailing plugs and had no idea what to expect from them.

It definitely drives better now, according to my highly calibrated butt dyno.

I kinda figured BHR might be interested in taking a peek. I got one of his first ignition kits and threw it on a nearly brand new car with all the latest ECU updates. Then I left it entirely stock, save a grounding kit. It makes for a good control sample.

 

good point and good idea.

 

Got the dumb young kid at autozone and he didn't want to try and find some kind of micrometer to measure the gap or understand why I'd want to measure the gap of used, pre gapped plugs.

Took this picture instead. The gap is about 1.5x the thickness of a credit card, and just a bit thinner then a penny. you can see the electrodes are only now starting to round off from wear. Remember, the plug on the right has been in the car since it was made. Plug on the left has only lived with the BHR ignition system. They cant have more then a difference of 5k miles or so.

 

I'll post some pics of mine next week for comparison. They should have ~25k on them with the BHR ignition and a little too much city driving

 

I'll try and find myself some feeler gauges that go up to .050+ (It's about time I owned some).

I wasn't getting misfires or anything. It just seemed like one of those things I should do by now.

Any idea how many miles I can expect out of the coils/wires? I like doing things before I have problems. (I have seen too many people telling stories that start with a bad coil that ends with a dead engine).

I don't even know what you've done to upgrade the kit since I got it, I've been inactive in the scene for quite a while. Hopefully you've fixed the clearance issue with the "Stupid, useless" engine removal bracket.

 

Now you need to dip these plugs into seafoam for a day or two. I'd be curious to see if the deposits will soften and become easily removable?

 

Ray did you get my PM??

 

Ahhhhh no
Dude not sure where you are getting pig rich from because I can show you pig rich plugs from an 8 and the do NOT look like that.

 

Razz has been like that since I first ever found this forum in 2008. Some things never change. I think he just likes saying "Pig rich"

 

that looks perfectly normal for something with 50K miles. no matter which Ignition system used.

Rotary Engine has been eating plugs alive since it came out. Most of you guys have never, ever had any Rotary engine before, but if you do had one(or more than 1), then you know that RX-8's plug is actually the longest life plugs ever for Rotary Engine. NOT because of Ignition system tho, it's simply because it's using Iridium, something NO PREVIOUS Rotary Engine has seen before.

In RX2 days, u be happy if ur plug can make 10K miles. (copper)

SA/FB? 10-ish K(Nickel)
FC and FD about 10-15K, sometimes 20 on the high side (Platinum)
FE/RX-8 , 30K, (Iridium)

Ignition Technology has been improved as well, compare to Dist/Cap back in the days, to now direct firing Coils.but it's all the same really, the biggest reason is the Engine itself.

If you are still on the Original OEM coils, meaning EARLY, original VERSION, Not even A, I would expect your plugs to fail sooner, but if you already have Version A(around late 2005), or even B(around 2008), you don't have to worry too much.

Some of you might say "OEM Coils can failed when new", so does everything else, who saids new means always work ?

Another thing about the Plugs, Denso plugs actually have better design than NGK, but no one seems to use it because NGK its OEM and Denso cost almost twice. I'm going to give that a shot. and come back some months later with the results.

 

I use Denso, (I think OD (Denny) does also) I really like them. they go well with my OE Coils.
Being a racing plug they are a little colder, no good for short distance low RPM use.

As far as pics above..they look totally (old, but) normal to me..

 

yep--i run the densos--the 27's and 31"s. I get much better service out of them. I have the msd 8247 Ig coils on the oem dwell ( dont need to change it). The ground straps on the densos are stronger and you can gap them with no worries--still do it gently.
i keep 2 sets--i clean one set via a cheap $30 untrasonic machine and use a toothbrush. Run one set, clean the other---I have been doing this for 2 years now and they still look really good with no measureable wear or increase in resistance.

 

I hope you just miss posted about PMing Ray - he does not read PMs

"Do NOT send me a PM here. E-mail me at "Charles@BlackHaloRacing.com". Thank you. "

 

so what is the advantage Denso plugs have over NGK?

 

10.9 afr at wot... Those plugs had about 25k on them

 

Looks different to me, darker, much darker ... but heh its a photo right.
It's about what you would expect running at 10.9 afr I would say.

I pulled a plug from an R3 (trailing front Rotor) that was completely black.

 

Nice! those plugs were also around 2 years old when I pulled them.