spark plug analysis

[tonym]

I'm sure that there was a post a long time ago that had a link to a website where a guy diagnosed engine problems by the spark plug tip colour. I don't mean tan is ok, sooty is bad but the finer points and markings on the metal tip; he could tell by the markings whether the car was timed correctly etc. I can't find the web page anywhere, does anyone remember this link or have can point me in the right direction?

[wilf]

Tone - I think it was me, should have the url at home, will post it tonight.

[tarmacscratcher]

Or maybe this is the one?
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

[Noel]

Hi Tony,

Try this

http://www.akamoto.co.uk/resource-spark-plugs.htm

Noel

[TINKA]

or even this

http://www.4secondsflat.com/Spark_plug_reading.html

[Sidecarbod]

I recon it was this post:-

http://autos.ninebean.com/cobraclub/...021&highlight=

[mikey]

Originally Posted by tonym

I'm sure that there was a post a long time ago that had a link to a website where a guy diagnosed engine problems by the spark plug tip colour. I don't mean tan is ok, sooty is bad but the finer points and markings on the metal tip; he could tell by the markings whether the car was timed correctly etc. I can't find the web page anywhere, does anyone remember this link or have can point me in the right direction?

Assesing mixture and temperature range by colour is fine. With regards timing by plug colour, just dont go there as its b---arks.

Befoore you check mixture make sure you have a plug which matches your state of tune. Too many think a racing plug is a better component, when actually you are running too cold a plug and getting a poor burn. Stat off with a N5 or equivalent - if your motor is well tuned for performance an N6 at the coldest, but you will be running big valves and a hot cam with most of the use at high revs to warrant that.

Set your timing to where you think iy should be and gauge the changes by driveability. Dont forget it is also about speed and ammount of advance not just initial advance. Read a few good articles first.
Mike

[tonym]

yep this is the one, thanks sidecarbod and Tinka

[Sidecarbod]

Originally Posted by tonym

yep this is the one, thanks sidecarbod and Tinka

hi Tony,

Even though I posted the website I agree with Mikey, I don't think it is possible to read as much from a plug as the guy on the website would have you believe.

I think that the colour band on the earth strap may well change with the timing but this is due to the fact that the change in the timing has changed the heat of combustion. Other factors can just as easily change this temperature and therefore the colour band.

The stuff about different areas of the centre cone may well be true.


Check out your plugs with reference to the site and let us know what you think.

Regards,

Pete

[tonym]

To be honest, i took my plugs out earlier and i thought they were ok. I then got curious about the site mentioned and wanted to read it again, purely for my amusement, not as a tuning aid. many thanks to all who replied