Spark plugs - hopefully a simple question...

I recently got some W5DPO's for my G60, having found out that it still have W6's in despite all the work that had ben done (coupled with the fact that they have done 40k miles now so probably need a change). Looking at them, the tips of 3 look exactly the same, and one looks very slightly different from the other 3. I'm talking fractions of a mm here, but even so it is different. What I'm wondering here is, given how the spark characteristics are very dependant on the geometry of the tip, how similar do all 4 need to be?

I know this is useless without a pic so I'll post one up later. Hopefully this is me worrying about nothing, but I'd appreciate any thoughts.

I've never had any problems with things like that on my engine, but I don't know how fussy G60s are with plugs. It's not uncommon to get 1 plug from a different batch that's very slightly different mixed in with a set of 4 though, happens all the time with the cheapy NGKs I use.

Ok cheers Kev, thats good to know. I still haven't got the picture done - not had much time here for a couple of days.

Here you go....Pics....

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Most of them look like this. But....

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One looks like this.

Difference on how the side electrode is positioned relative to the central one. I presume I am worrying about nothing here?

Yep, nothing to worry about at all there mate.

My Audi RS plugs (F5DPOR) looked exactly like that and they came from an Audi dealer!

I don't know about yours but the ground strap appears to be welded on on mine, so might explain the slight differences (and price as it's an extra build process!)

Great, thanks Kev. Nice to be worrying about nothing for a change . I think you're right about the welded earth on it - mine look like they are too.

I guess the larger air gap would increase the capacitance of the centre electrode and therefore require a proportionally larger amount of electrical energy / current for the spark to bridge the two contacts?

Also the greater the distance, the harder to break down the air, and create the spark (more a question of conductance than capacitance I think). However (fingers crossed) that effect will be small and there is adequate voltage the cause breakdown. If it works on one and not the other then I do have a problem to look at

cool good luck with it mate! I'm not great on the electrical side of stuff.