I have a lot of hesitation really around the 7000 rpm and 8000 rpm.

It was like 7000rpm wooo (slient) wooo (silent) and get up to 9000 rpm.

It is no denotation - there is just silent small gaps = according to my internet research, it is called missed fire

Well last time I only have this - I change my plugs and went away, but I only have the plug for 11000km. They are colder plugs - NGK9 leading NGK10 trailing. I was so scared they are fouled and I could not sleep.

I rushed to my mechanics tonight.

I have taken it out today by my mechanics (11000km after install - 4 track day, nanny driving around town), and compare with the stock (similar track days and nanna driving).

It is what it looks like when I taken out and put it side by side of my OEM old plugs


Wei, my machanics clean it very nicely


After the clean and reinstall - NO HESITATION. The lower rev is also smoother!

Oh I also clean the filter and check for DTC code; just to complete the whole lot.

 

Taka I thought you were going for some brand of spark plugs you mentioned in the other thread, how were they?

 

Not my hand LOL... Yeah he found it sexy to have long nails

It is nicer on the road. Feel smooth going - I don't know if it is the new/clean plug or the colder plug. They are the same price (racing from Japan and OEM from dealer). $80 each either way for me.

I think carbon deposit accum faster in colder plugs - but it is not overheating, denotated, or oil fouled.

http://www.centuryperformance.com/spark2.asp

 

Okay....can you run this by me again Taka? The pic shows two plugs....both had done 11000k's. The OEM's removed at 11000k, and the replacement removed recently at 22000k after having done 11000k, right?

The gist of what you are saying is this.........clean your plugs at every 10K service??

Cheers

 

No No No No

Sorry to confuse you what plug I use.

The right is the leading plug that comes with the car (NGK 7) (I kept it for reference use), done 22000km on them. Diagnosis: Small wear and tear, carbon/ash deposit (which is normal for rotary).

The left is my current leading plug. Colder (NGK 9), done only 11000km. Diagnosis: Minimal wear and tear, carbon/ash deposit. No signs of overheating, denotation, or oil fouling (which are all signs of wrong heat range).

So from my observation I have made the following assumptions:

- The NGK-9 (colder plug) is ok for track and street use.
- The OEM plugs take longer or carbon buildup and last longer to misfire.
- Misfire is most likely due to plug carbon/ash deposit, but also need to check tuning *(if done), and the air filter (to see if it is very dirty). DTC code should be checked too.
- When misfire occur and see the plug like this ----> clean them.
- If it has wear and tear shown. Do not waste time cleaning them, buy a new set.

It is merely my experience... but it is what I will continue to do. I will clean them when I feel there is misfire.

 

Thanks mate....

 

Taka,
The cleaned plug looks brand new. How do you clean these plugs???
I think we all would like to know.

Regards
Rexi

 

I think carrb cleaners work

 

No chemical and rubbing.

But I am sure there is commerical product that does the same.

My mechanics did not want any rubbing or chemicals into my plug, since he fears that will damage the tip (since the gap and the heat range) and the base electrode (whatever ). I saw him putting the plug in a box of fine sand and has a compressor to blow the sand to the plug. So it just get rid of the ash deposit. Then just air blow it clean (no more sand) and take a picture like above.

I did not say anything since I don't know the pros and cons of using that but that is what he uses to clean.

Labour is $70 but it saves me $320 for the plugs. (well Mazda sells at $80 each ). Japanparts.com sells racing plugs at the same price

 

From what I've read abrasive cleaning (e.g. sand) is a no-no with our plugs. You can order the plugs from www.sparkplugs.com for US$79.96 with shipping can't be close to $320. New has to be better than cleaned this way.

 

The only reason it'd be a no-no is due to the risk of damaging the fine electrodes these plugs have. If the operator of the plug cleaner is careful (as Taka's guy obviously was) then there should be no problem.

 

so why did you switch to colder plugs if OEM temps are actually longer lasting??

 

Becauses OEM plugs have potential to misfire on the track. I love to chase the Porsche Carrera at my home track (note of my fav saying: bloody Porsches get out of my way! ) where there is a long back straight that you can get up to 8000rpm at 4th gear. I don't want any hesitation at that point . Plus colder plug get heat out quicker and more suitable for sustained high rpm

Of course, if you don't track the car - why the hell do you want to have colder plugs on the road - say during off season.

My answer would be typically: I am a lazy ***

 

niiiiice lol

 

Well after many weeks of frustration with my car, visits to dealers who insisted the plugs were ok, my plugs came out today after 21,000kms.

I think the pictures speak a thousand words!

 

Time for a change. Lots of deposits

 

What scary plugs they were

 

Thanks for the info Andrew.

Damn, my plugs were replaced (as part of the startup upgrade) at about 9-10K. I'm now over 28K so any time in the next 2-3K I might experience the same problem. Good thing to know about.

 

YuK!

I shudder to think what mine must look like. They have been in for 58K already.

Might have a look at them today before I head off for the nationals.

 

Depends on your normal drive I guess. I checked mine around 50k and well, they would have been worth changing at the 60k service, but nothing like those pictured

 

Those plugs look oil fouled....I'd watch your engine......

 

When the plugs were changed, I also got a pod filter installed. While they were doing this they found oil lining the inside of the tube that the MAF sits on and around the inside of the airbox.

At this point the guy changing the plugs mentioned that at high revs you get an air/oil mix from the engine being forced back up the air intake.

OK well both Taka and I do a lot of track days, and I have done a lot of skid pan work in the last year (4 x 1/2 day session with me and the wife both using the car). So I could see the merrit in that.

However you could also see an oil stain on the airfilter and wire mesh on the inlet!!! so my thoughts at this point are that the car MAY have swollowed a mouthfull of water on the skidpan (VERY VERY oily pan last visit).

However the oil in the intake was very VERY clean so we really dont know.

I have been told that I may want to get a catch can installed.

 

This is a great find for me. I will be looking into my plugs to see if I just need to clean them or change them. Thanks!

 

Ouch! That's not exactly a long service life for plugs..... it's NOT your engine

It's been our experience that OZ ( and New Zealand ) Unleaded gasoline *still has* tetra-ethyl lead added, just not anywhere near as much as the gas companies used to put in a few years back

Japanese gasoline by comparison is higher octane ( 120+ RON at the pump ) and *absolutely* Unleaded , so Rotarys don't exhibit early plug failure when run in Japanese domestic units locally; 100,000km service without any loss of performance is typical

Another *unfortunate* spinoff of adding lead to gas, is it reacts with catalyser components which use a very thin plating of platinum on internal screens; and these too can fail early

GW