Sparkplug Reading ?

2 passes on motor only...What does the reading look like on this plug ?? C16 Fuel

Based on "that" picture, you're lean enough to melt the top of the piston.

Looks fat on fuel to me.i'd be wondering more about all the rust on it.

I'm seeing specks of shinny stuff. I'm guessing it was driven back to the pits making the color an unusable variable.

Curt wrote:Based on "that" picture, you're lean enough to melt the top of the piston.

Well the fumes are soo strong, can't stay in the shop long lol...Fuel pressure is at 7-1/4 ...1250 dominator...Hard to believe its running lean?? That rust color is what concerned me...All plugs are the same...Mabe i was sold some mixed fuel insted of full strength C16...No water in oil or cyl's' and i used a scope and piston tops look fine...Temp never got over 180 at the track

Did the motor cool down before you pulled the plugs? IF that's rust, it CAN form rapidly with humid conditions that occur when a motor cools (especially at night, humid days..). How about a shot from the side of the strap? There's plenty of carbon from a rich condition in the first pic..

The mixture at idle is not what I would be concerned with. It is at WOT. It would not be unusual for it to be pig fat on idle and starving for fuel at the stripe.

DFI429 wrote:Did the motor cool down before you pulled the plugs?  IF that's rust, it CAN form rapidly with humid conditions that occur when a motor cools (especially at night, humid days..).  How about a shot from the side of the strap?  There's plenty of carbon from a rich condition in the first pic..

It was cooler later that evening, and i keep it in my shop except that night i left it on the trailor..I fired it just long enough to back it in the shop the next morning... I will get a side shot in a few mins

Curt wrote:The mixture at idle is not what I would be concerned with. It is at WOT. It would not be unusual for it to be pig fat on idle and starving for fuel at the stripe.

First time out testing and i was trying to watch and look at everything...Not sure what was going on....

Not much of a track , cause they dont prep much at all...Just a short clip of a somewhat run here..Had to let off....Camera man was drunk also i think....lol

https://www.youtube.com/watch?v=-TJwzyTimzA&feature=youtu.be

You need to kill the motor at the finish line and coast off the track and pull a plug or two and install other plugs to drive back to the pits. if your trying to read plugs after any thing else your wasting your time
Also look like a prety small gap

Ace

powerstrokeace wrote:You need to kill the motor at the finish line and coast off the track and pull a plug or two and install other plugs to drive back to the pits. if your trying to read plugs after any thing else your wasting your time
Also look like a prety small gap

Ace

I had timing set at 30 total, and plugs were set 25 for nos...But i havent sprayed any yet till i have tested more and get bugs worked out....

As Ace said,,,,,,,, you can't read the plugs if you don't click off at the finish line. Sorry, but these pictures wont tell you anything.

Curt wrote:As Ace said,,,,,,,, you can't read the plugs if you don't click off at the finish line.  Sorry, but these pictures wont tell you anything.

Going to get another set of plugs in a few...I will shut her down and change 1 or 2 and check them back at the trailor next test run...

Extended idling will pollute your readings, but by your pictures, the center insulator was cleaning minimally, indicating rich or cold (or both), and the strap is 2/3 clean with a haze of carbon, indicating timing may be high, with some idling to haze it over.  Don't dismiss your plugs altogether just because you didn't shut down within nanoseconds of the run.. 

powerstrokeace wrote:You need to kill the motor at the finish line and coast off the track and pull a plug or two and install other plugs to drive back to the pits. if your trying to read plugs after any thing else your wasting your time
Also look like a prety small gap

Ace

^^^^ all this is the correct way unless you get someone to tow you back. I've witnessed guys try to get the most out of a carb idling in the driveway...   Aint gonna happen.

Curt wrote:Based on "that" picture, you're lean enough to melt the top of the piston.

I hope you were joking with that comment.

richter69 wrote:

Curt wrote:Based on "that" picture, you're lean enough to melt the top of the piston.

I hope you were joking with that comment.

"that" picture has shinny specks on the plug. Is that the way you run yours?

Curt wrote:

richter69 wrote:

Curt wrote:Based on "that" picture, you're lean enough to melt the top of the piston.

I hope you were joking with that comment.

"that" picture has shinny specks on the plug. Is that the way you run yours?

Soo, do ANY shiny specks automatically qualify as a result of a LEAN condition to you regardless of any other indications???  Or just most...  

The plugs are junk for reading.

Fresh plugs, start it and do a burnout, click it at the stripe or as soon as you can get off the track (c4 problems).

As far as anything shinny.... Hell it could be antisieze which is a no no in a nitrous motor.


Only thing i get fron that pic posted is is was run a bunch and not in a way to make any tuning descisions......

That's the reason that "that" was noted.   

DFI429 wrote:Extended idling will pollute your readings, but by your pictures, the center insulator was cleaning minimally, indicating rich or cold (or both), and the strap is 2/3 clean with a haze of carbon, indicating timing may be high, with some idling to haze it over.  Don't dismiss your plugs altogether just because you didn't shut down within nanoseconds of the run.. 

Unless my timing light is off bad...I had it set on 30* total...Running NGK 10 plugs....C16 gas i hope wasn't bad or mixed with something else...

DFI429 wrote:

Soo, do ANY shiny specks automatically qualify as a result of a LEAN condition to you regardless of any other indications???  Or just most...  

No, most of the time I would say it was detonation. But he's running very high octane and it doesn't look like he made a full pull..  The picture sucks, and he's wanting us to diagnose his tune up. I guess you have the answer?

richter69 wrote:The plugs are junk for reading.

Fresh plugs, start it and do a burnout, click it at the stripe or as soon as you can get off the track (c4 problems).

As far as anything shinny.... Hell it could be antisieze which is a no no in a nitrous motor.


Only thing i get fron that pic posted is is was run a bunch and not in a way to make any tuning descisions......

C4 is doing its job and hangin strong......  

Gettin to neutral at the stripe is a challenge ........


......and you aint leaned on it yet either.