Spark Plug Coloring
#1
Spark Plug Coloring
Can someone with a little plug reading experience take a look at my plugs and give me a idea of how the engines tuned? From what I see from the ground strap I may be able to get away with a degree or two of timing. The fuel looks good to me. One plug was with 14* and the other had 16*. Both runs made a little over 13psi. Fuel was approx 97 octane (mix of 93 and 110). Thoughts???????
Last edited by Monte4ever; 09-17-2015 at 08:45 PM.
#3
They do not have any drive time of them. The pictures came out a little dark. The car was cut off right at the end of the pass. The plugs are actually very clean with a light coating of black on the bottom threads and the porcelain is still white. Later today I'll take a few more.
#4
Here's a few more pics. As you can see the plug with 14* has a small mark on the tip of the ground strap and the plug with 16* has a mark in the center. Looks to me like I can use 2* more timing and still be in the safe zone. I may need to add a little fuel too.
Last edited by Monte4ever; 09-18-2015 at 05:57 PM.
#7
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plug looks good. Ive always learned not to go past the elbow in the strap. Once you get that nice radiant blue line at the bend, leave it alone! assuming theres no fine speckling we cant see from the pics, looks good! I cant seem to tell but if thats a projected tip plug like a TR6, i would get into a NON projected tip style plug to resist any more chances of detonation.
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#8
Thanks for the advise. The plugs are NKG #7 non projection tip. Later today I will see if I can cut the threads off without disturbing the fuel ring. I do see 3 or 4 little black specs on the plug with the distinctive timing mark (16*). Serioussn95 I'm trying to get the blue line right before the bend. Next time at the track I may just add 1* to see how it looks.
Last edited by Monte4ever; 09-19-2015 at 09:08 AM.
#9
I cut the plugs and the first thing I thought was WOW.....I need to add some fuel. My data log showed that I averaged between 11.3 and 11.5 at WOT. Looks like I should take it down to 11.
EDIT: Just read that E10 gas (Michigan) will show a very light colored ring so I may be good. Thoughts......
EDIT: Just read that E10 gas (Michigan) will show a very light colored ring so I may be good. Thoughts......
Last edited by Monte4ever; 09-19-2015 at 04:48 PM.
#14
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If your keeping the boost there...I like the mark on the 16* plug, I wouldn't change a thing. Once you see color on that second thread you're "on the edge" IMO. Personally I wouldn't add any more timing, and I steer clear of the bend all together with turbo cars. I prefer my strap to look more like the 14* pics when running big boost. I'd turn it up a pound or two with the 14* tune and see what the plug looks like.
#16
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A couple of questions as I'm far from an expert plug reader.
Did the change in timing 2 degrees improve performance?
Will a leaner or richer mixture move the heat mark around?
Do different brands of plugs show the same results? In other words are all ground straps the same thickness?
I'd assume every cylinder will look slightly different.
I notice different shading if you will on the porcelain from cylinder to cylinder. I attribute that to the fact that every plug indexes differently cylinder to cylinder. Easy to see with the heads off.
Want to really feel weird about your plugs, run them for a bunch of street and track driving then look at them with a microscope. Pretty scary actually.
But, you can sure see signs of distress! Like the TR6's I was running before I knew better.
Thanks for getting me to look at mine at 1:00 AM! :-)
Ron
Did the change in timing 2 degrees improve performance?
Will a leaner or richer mixture move the heat mark around?
Do different brands of plugs show the same results? In other words are all ground straps the same thickness?
I'd assume every cylinder will look slightly different.
I notice different shading if you will on the porcelain from cylinder to cylinder. I attribute that to the fact that every plug indexes differently cylinder to cylinder. Easy to see with the heads off.
Want to really feel weird about your plugs, run them for a bunch of street and track driving then look at them with a microscope. Pretty scary actually.
But, you can sure see signs of distress! Like the TR6's I was running before I knew better.
Thanks for getting me to look at mine at 1:00 AM! :-)
Ron
#17
Those are some good questions. I'll try to answer the ones that I kinda feel comfortable with. Yes, adding 2* picked up 2mph. Idk if that's good enough to justify the change or not. The 14* run had a funky 60ft of 1.78. The 16* run had a even funkier 60ft of just over 2.0 ( yes I need to work on my suspension ). It picked up 2mph over the 14* run. So I think the top end came alive pretty good. As far as adding more fuel and the effects it would have on the ground strap marking I would think that it would not have too much of an effect at all especially when adding small amounts ( 11.5 to 11.0). I could be wrong as I'm learning this stuff too. I also noticed that the porcelain was a little darker on one side than the other. I read that that was caused by the ground strap's position on the plug. In other words it covers that side of the porcelain shading it from fuel (I think).
Last edited by Monte4ever; 09-22-2015 at 08:32 PM.