Hi,

today i decided to remove my sparkplugs for checking if they are running too lean or too rich.
But i am not so good to determine my sparkplugs, because of this i made some photos for you in hope you can help me out.

My car is equipped with a Comptech Supercharger + Aftercooler (stock kit, no modifications made).


On the following pic i gave every sparkplug a number:




The plugs i use are the new oem-type, the next pic shows you the seriesname:




Ok, here are now the sparkplugs, starting with number 1 to 4:










One the following 2 pics you can see the whole sparkplugs:







Now, what do you think?

 

They look OK to me but the bright light that you are photographing them under makes them look a bit on the "whitish" side. Assuming this is the case, I'm going to stick with that assessment since I do see shades of a light brown coming through on all but your #1 plug and even that one, the negative electrode looks OK.

 

I agree with xviper. It looks like a clean burn (assuming the ceramic is a bit brown under regular light). Those plugs look brand new...

 

Thomas, they appear to be normal to me. A stock S runs pretty lean AF# at part throttle and cruise. Reading the plugs after a normal drive might not provide enough insight into a rich/lean condition.

I still reccomend that you remove and inspect them much more frequently than with a stock engine. I've been in the habit of pulling them every oil change.

 

Thanks for all your comments, i am feeling a lot better now


[QUOTE]Originally posted by Slows2k
Thomas, they appear to be normal to me. A stock S runs pretty lean AF# at part throttle and cruise. Reading the plugs after a normal drive might not provide enough insight into a rich/lean condition.

 

I dont understand how people expect to 'read' a plug after they have let it run at any engine speed apart from the engine speed they want to read.

If you went for a 9k blast, then came home at a normal pace, then idled the car for 30 secs after you parked it, you would only be 'reading' the idle. And since closed loop it will always be running 14.7:1 for stoich, your plugs will always look the same so long as the lambda sensor is fine.

Whatever was happening at WOT and 9000rpm is long gone and the plug has cleaned itself of the richer A/F ratio remains.

If you want a WOT plug read, then run the car at WOT and under load then switch the engine off.

 

I had a nice laugh thinking about what would happen if somebody tried this on the highway.

 

Ok, not a highway, but any semi quiet road or industrial estate is more than fine.

 

It's a pretty common practice on 2 strokes, Also called the "Clean plug read".

 

Checking the plugs like this is an indication of general, overall operating conditions. If you have a routine lean condition, this will show up as would a routine rich condition. For me, with a daily driven car, this is what is most important. Unless you are "tuning" the car the poor man's way, who really cares if you have a lean condition for a split second over a rev band of several hundred rpm? If it's at the low end of the rev range, I'm not concerned. If it's for a fraction of a second at 9000 rpm, I'm not concerned either. I don't drive there all the time. If you do drive there all the time and are that worried about those tiny momentary blips of bad A/F mix, then you really should be putting the thing on the dino or have a good A/F gauge on your dash.
If my engine was running lean ALL the time, then I would care and the plugs would tell me this.
It is your perogative to NOT rely on this method to judge engine health if you think it doesn't serve any purpose. This way has served my well for decades and has not failed me yet. If it is wrong, I guess I'll be in for a nasty surprise one day but I'm not holding my breath for that day to come. Don't lose any sleep on our account. Sensible people use this method as only one tool of many to gauge how our engines are doing.

Addendum:
Here is a link to an interesting write-up:
http://www.ultralightnews.ca/articles/read...gsparkplugs.htm
True, it is for an ultralite engine but the principle is the same, PLUS, almost EVERY car service manual has something like this, showing pictures of how to "read" your spark plugs. It is an "age old" technique that has not lost its value.