This guy on uk.rec.cars.maintainance has the following question:
tinyurl.com/6era
For those not newsgroup or google enabled:
"Is there anything to be gained by using special plugs?
I saw some in Halford's the other day - with three side electrodes.
Worth bothering with?
Or the platinum ones?
They didn't seem to have a whole range of different ones for different
cars,
as they do in the case of the conventional plugs.
Is it not critical?"
I've often pondered this. Is a big juicy spark really better? Why?
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These are my own opinions, and not necessarily those of all Toads.
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Well, you convinced me to wander into the realms of the techy ones.
I understand that a "clean" spark is preferable as the closer it is to the optimum (in duration and intensity) the better the combustion cycle. Multi electrode plugs with rare-metal cores will offer a cleaner spark and lower running temperatures, increasing their life and improving economy/performance. They also provide better combustion as the ignition is over a larger volume (multi-point plugs anyway).
Or summat like that.
BTW, kind of academic for those with glow plugs. Yes Toad, that's DIESELS......
(Grabs coat and runs for the door)
As an aside, have you been down our way recently? The council have put up a new "danger, Toads Crossing" sign, some 6 months ahead of the usual migratory season. Get's kind of slippy outside in August, it does.
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Well, you convinced me to wander into the realms of the techy ones.
Not my choice but you don't know how much of a battle it was to get plugs mentioned at all!
I've heard that, but as I said in more detail in the post Mark deleted from discussion, if you do get 10 per cent better propagation surely the timing would need to change?
BTW, kind of academic for those with glow plugs. Yes Toad, that's DIESELS......
;-)
As an aside, have you been down our way recently? The council have put up a new "danger, Toads Crossing" sign, some 6 months ahead of the usual migratory season. Get's kind of slippy outside in August, it does.
;-)
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These are my own opinions, and not necessarily those of all Toads.
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Must be the same reason why Alfa on some of their models and now Honda on the Jazz have 2 plugs per cylinder.
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Not quite.
Multi - electrode (or for that matter exotic material electrode) plugs give longer life.
Twin plugs actually fire at slightly different times.
This is to prolong the burn and ensure even better combustion.
That works - the twin spark versions do produce more power.
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Multi-electrode plugs certainly last much longer. I just changed the Bosch 3-electrode plugs in ye olde Polo after 24k (supposed to be 20k). The old ones were working fine, and didn't look too bad either.
If buying from GSF or such like, for the money (about 2 quid each) it's not worth bothering with anything less.
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As far as I was aware the only reason to use multi-electrode plugs was for extended service intervals. Sharing a spark between the electrodes will decrease the rate of erosion and gap increase over time.
Only one electrode will ever fire at any one time, the one with the least path of resistance at that instant.
MM
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yes perfectly correct and they run cooler adding more life and cool cold running. But remember to undo them every six months or they can seize. Regards Peter.
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I have used the Bosch 4 electrode plugs on a Cavalier 2.0i, Hyundai Accent 1.5 Auto, not mine, and a 16v Nissan.
They do last forever(ish) but I can't say I have noticed much difference otherwise.
Their main advantage is that you don't have to muck about with feeler gauges when fitting.
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I might add that I once tried the slightly more expensive 4 electrode Bosch boy racer plugs. 3 electrodes versus four gave no noticable difference.
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Hi there!
I\'ve got a Nissan Skyline (2.5litre straight 6). The engine requires three-electrode platinum sparkies because they are very hard to get to (each plug has its own coil mounted on top, and the intake manifold goes right over the engine). Using these plugs means that they don\'t need to be changed until every 100,000 kms.
I haven\'t bought any yet, but Im told they cost NZ$25 each - a bit pricy when you need 6 of them!
Dorian.
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'scuse me for being sceptical but they seem like an attractive gimmick to me. Might be useful on a peformance car but on a Rover 416, Ford Escort or Cavalier etc surely there's no noticable difference?
Something extra extra to part the motorist from their cash if petrol tax isn't high enough already! I would defy anyone to notice the difference in a blind test.
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Yeah, I did hear that multi electrode sparkies are better for engine life.
Twin plugs is a different issue. I can fully understand how they improve propagation time speed. (And reliablility in \'planes)
But I\'m guessing the timing has to be adjusted.
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I would not buy anything else, I have found that they are comparable in price, at worst a couple of quid extra, than conventional plugs, and I have always noticed the difference. Untill now I had been putting them into Carb cars, however just last week I put a set of Bosh super 4's into the 1.8 Ecotec Vectra, and again I noticed a big difference in mid range tourque, I am keeping my eye on MPG but it is too early to report.
I will admit this is the 1st plug change I have done on the Vectra (which has a FSH), so I cannot be sure how long the GM twin electrode plugs that I replaced were in. But they did not look too bad.
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Doesnt the spark jump across the path of least resistance? Or does the spark really go across all electrodes?
One problem with multi electrode plugs is that you cant adjust the gaps. The Bosch plugs i used in my old Jetta 16v used to last 12-15k miles before serious triangulation of the centre electrode.
Ben
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