spark plugs position

[pete.triumph]

i copy and pasted from NGK WEB page . looking at the flame spread it looks like it spreads more behind the electrode not what i thought it would do and the but that looks like a 66cc wiper sniper engine

FLAME SPREAD
NGK's Iridium IX Spark Plugs are designed with a tapered cut ground electrode. This new shaped electrode serves two purposes. Firstly, it allows for a better spread of flame during combustion. Secondly, in conjunction with the 0.6mm diameter centre electrode, it helps reduce the electrode quenching effect.

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< Tapering the ground electrode reduces the volume of metal mass at the plugs firing end.

​

The flame kernal is therefore less inhibited by metal while igniting the fuel mixture, allowing the flame to have a better spread and achieve more thorough combustion.

This increase in the flame spread means the fuel mixture is burnt faster and more completely, resulting in the engine delivering more power and acceleration, better responsiveness, and increased fuel efficiency.

To demonstrate, these images were taken during combustion by a high speed camera. >

 

[1olbull]

@pete.triumph
Then the iridium plug IS better. Albeit not likely measurable on a butt dyno.
So now explain the indexing . . .
I know this was done around the race track, that's why I did it, BUT now that I think more about it the valves are both closed at compression and ignition are they not?
If so, how can the direction of the open electrode end matter?
Interesting stuff, pete.

 

[pete.triumph]

indeed but if the iridium burn "faster" won't that advance timing slightly so may be have to re tune or retard timing a fraction to make full use of any benefit !, but if you look at the iridium flame front you can see how it expands more at the open end of the electrode witch is why i thought to index the plug so the flame front would be go more towards the center of the cylinder.

​

 

[cusso ken]

So many variables in a simple equation, induction ,compression , ignition and exhaust, a degree of timing either way before The piston reaches top dead centre would IMHO make a lot more difference than indexing of spark plug ground electrode the centre is the electrode and the outer contact is the ground electrode ,the spark plug gap is another variable as the centre electrode is burnt away ,as is carbon build up in the combustion chamber these things do not happen overnight and the "butt Dyno" mostly fail to detect the gradual and mostly minor loss of power as we tend to turn up the wick as the light diminishes especially on a powerful bike like ours

 

[gra53]

Ruzz - it's more than 60 posts now. I'm over 58,000 klms and heading for the dot com ride in QLD next week and being slack won't get around to changing them , I'm paranoid, I'm still on the original plugs and no indexing.

 

[1olbull]

So many variables in a simple equation, induction ,compression , ignition and exhaust, a degree of timing either way before The piston reaches top dead centre would IMHO make a lot more difference than indexing of spark plug ground electrode the centre is the electrode and the outer contact is the ground electrode ,the spark plug gap is another variable as the centre electrode is burnt away ,as is carbon build up in the combustion chamber these things do not happen overnight and the "butt Dyno" mostly fail to detect the gradual and mostly minor loss of power as we tend to turn up the wick as the light diminishes especially on a powerful bike like ours

We are picking the fly $hit outta the pepper here with this discussion, but in a race hundredths of a second can sometimes matter.
For our street use . . . no way!

 

[ruzzle]

We are picking the fly $hit outta the pepper here ..........

LOVE it!!!!

 

[Wrecka]

Would fitting the spark plugs so the gap of the spark plugs faces towards center of the combustion chamber make any difference ? as the plugs are fitted at the side edge of the cylinder rather than anywhere near the middle unlike other bikes so at point of ignition the flame would start to spread outwards towards center without the obstruction of the probe of the plug , might run smoother i wouldn't think there would be any noticeable power wise.but if there is a small benefit why not do it may have swap a plug or two to get position right

Thats very fine tuning indeed

 

[cusso ken]

We are picking the fly $hit outta the pepper here with this discussion, but in a race hundredths of a second can sometimes matter.
For our street use . . . no way!

I was just stating the blatantly obvious, minor differences in power on a over powered machine like ours would not be noticeable except for the placebo effect, but an interesting thread just the same,

 

[TURBO200R4]

We are picking the fly $hit outta the pepper here with this discussion, but in a race hundredths of a second can sometimes matter.
For our street use . . . no way!

I JUST HAVE TO DISAGREE I THink that we are picking pepper out of fly $hit. just my opin
either way i think i will pass on the pepper

if we are going to be nit picking there is an old wife's tale that goes something like this. that the plug and the head thread matching flush at the surface and if you get like 1/2 thread hanging out that it will glow red an cause a pre igntion.