Dookie_Rx-8

Just a thought..

From reading around it sounds like spark plugs on the rx-8's are weak. What kind of spark plugs are stock on the rx-8? So what if u change it to them platium 4 tipped spark plugs would they help in anyway

brothervoodoo

Hello Dookie,

There are stronger stock RX-8 spark plugs. Try a search, don't recall the exact thread.

BTW, check out the WEST forum regarding a SF get together...

wakeech

the design of the NGK plugs for the rotary engine aren't the same as the multi-pronged downward pointing plugs you might find in a piston engined car...

RX8on19s

Dookie,

Information below is from the RX-8 dealer repair manual.....

CAUTION:

If a spark plug that is not as specified is installed, sealing performance will be deteriorated. Install only the specified spark plug when replacing.

SPARK PLUG SPECIFICATION

Type - NGK
Leading side RE7A-L*1 or (RE6A-L)*2
Trailing side RE9B-T*1


*1
Standard equipment
*2
Hot type plug: Available only for customers who often drive their car at very low speed which causes the plugs to foul easily.

Dookie_Rx-8

Theres no other after market Spark plugs for the rx-8?

Nubo

In one of the oil threads it was mentioned that if a car manufacturer specifies a specific brand of oil, then it must provide that oil free of charge; I wonder if the same applies to other consumables, such as spark plugs?

rotarygod

The stock spark plugs are very good. Alot of time and effort was spent developing a new type of plug for the Renesis. They are not made out of Platinum but rather Iridium which can be much smaller, stronger as well as a better conductor than even platinum. Of course at about 10 times the price of the RX-7 spark plugs, they had better be good. Don't even worry about them. Just leave them be. The issues aren't with the plugs but rather how prone they are to foul from fuel. This however is an ignition timing and firing order problem and not a plug issue.

RX-jimenez

Well if i am corect i think Denso Iridiu Power Racing Spark Plugs, do one for the Rotary Engine....you may check there..

Katchoo

Anyone have a clue how much these plugs cost? I have seen some really high prices posted elsewhere and wanted to find out the real scoop.
-------------------------
To support the purchase of new plugs I have already started saving my dimes and nickels...*sigh*

241Commuter

Dookie, please click on this linke to the TSB on spark plugs. With a sufficiently creative story you can probably get the hotter plugs for free from your dealer, and it's doubtful you can make much of an improvement spending a few hundreds on aftermarket plugs over the Mazda iridiums. I'd save my pennies for a Canzoomer stage one mod.

Rx8Freehk

If Anyone is Intrested, when I had a Plug crack, they replaced all 4 plugs and it cost.... get this 210 Euro ($240.00 US) OMG THATS THE DUMBEST OF DUMB

JimW

$240.00 Dayam, that's alot of $$$$. for Spark Plugs.

Dookie_Rx-8

How do you know when to replace them?

mdw33333

Listen to RotaryGod, he knows what he's talking about.

Alessandro

Rotarygod, the mazdaspeed limited 300 release in Japan, will use a different sparkplug according to www.mazda.com perhaps a future developement of all 8s sparkplugs?

SMC

where did you have them changed at. husband got them changed at the dealership, plugs cost him 140. we had 2 fouled. anyone know why after 17000 miles there would be 2 fouled plugs

Go48

That's really not too bad for plugs in a rotary engine, IMHO. Remember, this is not a boinger where oil in the combustion chamber is not normal. In the Renesis engine, oil is purposely injected into the combustion chamber more or less continuously. Most of it gets burned and exits the engine through the exhaust system. But over time, unburned oil (carbon) will build up on the plug insulator causing it to fire less efficiently and then its a spiral downward with less of the oil being burned in the combustion process, more fouling, and so on until you have a fouled plug.

This problem is compounded by the fact that a very rich fuel mixture is injected to the engine, particularly at start up, and may be an additional component of plug fouling. Then on top of all that, if you drive short distances and don't get the engine adequately warmed up, and you don't get the revs up frequently, that will also compound the problem.

So, considering all of that, your 17K miles is not too bad. You might get more mileage on the plugs if your driving habits included longer drives and higher revs, but then the gas mileage might suffer. Oh well, pay for gas or pay for plugs? Decisions, decisions.

takahashi

We already have iridium NGK plugs... how much are we going to get more. Denso have iridium racing plugs but I heard JDM Denso is different from Overseas Denso...

Change the new set regularly and do something about the leads.

R Magic has a new leads for the 8 called "Plasma" ... Japan 8 are you here? Confirm this? it is in the RX-7 mag but not in the R Magic website yet.

Charles R. Hill

iTrader: (7)

I have been using the same plugs (stock) since I bought the car and I have never had any problems. Even under nitrous boost at 9,500 rpm the engine doesn't miss. I think many people misunderstand the purpose of spark plugs and what the temp ranges mean. Go to NGK's website for a great explanation on how they work and what they are supposed to do. To clean mine, the one time that I did, I used carb cleaner and an old toothbrush. At 30K miles they are still working great.

Charles

JM1FE

OK, here are 2 plug-related questions regarding the RX-8:

1. What's the down side of using the hotter plugs? My g/f does a lot of short trips in her 8 (work is less than 5 mi. away), but some longer weekend trips of about 2 hours. I think she's a good candidate for the hotter temp range plugs, but was curious about others' experience with them. Would they lessen the flooding risk (car is up-to-date on all TSBs).

2. We were about an hour away last week at dinner, and when leaving (late) the engine cranked over several turns before it caught. I had a momentary panic about flooding - if it *had* flooded and if the dechoking procedure had not worked, there was a snowballs chance in hell of getting roadside assistance out there at that time, or finding a rental car or other way home. I want to be able to deal with any flooding situation myself and get back on the road. So... how hard would it be to plull the plugs, defoul them, and get going again? I haven't looked for plug accessibility yet. I assume it would be:

- plull plugs (all 4? leading/trailing only? both from one chamber only?)
- defoul them (just evaporate the gas? spray them with solvent? brush?)
- reinstall plugs
- do the dechoking procedure again to build up oil pressure & seal compression
- crank and let combustion take care of any residue
I'd like to put together a minimal kit for this, and instructions. Another ideal would be to carry a spare set of plugs. I guess it's a similar risk of having someone transpose the leading/trailing plug whether they pull-and-clean or just outright replace.

Anyone tried this? Any suggestions?

dannobre

iTrader: (3)

I was runnig stock plugs for the summer....with an e-manage setup. The dealer swapped my plugs for the hotter plugs for the winter. And gave me the cooler ones to re-install for the summer when I drive the car a lot harder. I have had no problems with the hotter plugs...even with the leaner tuning....

I did notice a big difference in throttle response, and idle when the plugs were first new...

JM1FE

different-better or different-worse?

dannobre

iTrader: (3)

Better. My old ones were fouled because it almost flooded...and they never seemed to burn it off. I drive a lot of stop and go to work every day....and after two weeks post almost flood...I took it in for new plugs. I am taking it in on Friday...and I'm going to get them to pull the leading plugs so I can see how they are doing. The hot plugs seem better in the colder weather...with the short trips

Go48

[QUOTE=JI assume it would be:

- plull plugs (all 4? leading/trailing only? both from one chamber only?)
- defoul them (just evaporate the gas? spray them with solvent? brush?)
- reinstall plugs
- do the dechoking procedure again to build up oil pressure & seal compression
- crank and let combustion take care of any residue
I'd like to put together a minimal kit for this, and instructions. Another ideal would be to carry a spare set of plugs. I guess it's a similar risk of having someone transpose the leading/trailing plug whether they pull-and-clean or just outright replace. Anyone tried this? Any suggestions?[/QUOTE]

Can't answer your questions definitively, but let me make a couple of comments on your proposed solution to a flooding. All my opinion, of course.

Replacing the plugs is not necessarily the magic bullet solution for a flooding. The plugs may be firing but the surge of fuel into the combustion chamber may have washed most of the oil out of the chamber thereby reducing the compression to a point where the detonation--if it occurs at all--of the oil-gas mixture is not sufficient to get the engine running.

Plug fouling is often the result of a deposit of carbon over time on the ceramic insulator of the electrode, not necessarily just raw fuel on the electrodes. So, if that is the cause of the fouling, you would need to somehow remove the carbon from the ceramic insulator. A quick and dirty approach is to use a small piece of sand paper (yeah, really. An old dirt bike trick.) to actually sand the carbon off the insulator as best you can. Of course, this is a temporary solution and the plugs should be replaced at first opportunity.

If I was concerned about flooding as you obviously are, I would keep a set of new plugs in the car along with the proper tools to replace them and I would also make sure ahead of time that I knew the procedure for replacing them.

EDIT: If you are in a cold area you might also consider replacing the battery with the new replacement, 640CCA unit. (At your expense, of course. )