Ngk Iridium/platinum Spark Plugs

[RS4StagMan]

I've done a search and it has come up with some conflicting information on possibility of gapping down Iridium spark plugs.

The ones I have currently are the recommended plug for the RB25DET Neo engine-

BKR6EIX-11, Iridium pregapped to 1.1mm

The NGK website also lists the PFR6G-11, Platinum as an alternative also.

PS; NGK website lists the Stagea as seperate to the Skylines now.

http://www.ngk.com.au/sparkplug_imports.ph...500TurboRB25DET

I would like to know whether people have had some good or bad experiences with gapping these types of plugs down to say 0.8mm. Is there a special method to do so without damaging the plug?

The smaller gap will defintely help with LPG (as NGK recommend) and also slightly higher boost than factory.

OR just go plain old coppers is the go?

[QWK32]

if you want to go for a 0.8mm gap on an iridium plug, not just buy them already gapped to 0.8? or are the ones you have only newish?

Edited February 11, 2009 by QWK32

[zei20l]

ive regapped plats before no problems. the tip is all the same material AFAIK the core is what contains the platinum/iridium.

[RS4StagMan]

if you want to go for a 0.8mm gap on an iridium plug, not just buy them already gapped to 0.8? or are the ones you have only newish?

Yeah quite newish, under 10K kms old with factory 1.1mm gap.

[RS4StagMan]

ive regapped plats before no problems. the tip is all the same material AFAIK the core is what contains the platinum/iridium.

So just adjust the tip for required gap but do not lever off the core at all?

[wolverine]

if the car is running fine, leave them at 1.1mm

[zei20l]

lol no i mean INSIDE the plug is the material in question

but yeah unless your RB is misfiring, leave them at 1.1mm

[BKC34]

just a lil off topic, but i will always use plain old copper ones and this is why...

as my mate, (qualified mechanic building his own rb26/30 33) explained to me one day, iridiums are good, they will last around 100 000kms which is great however, there is nothing wrong with copper ones, infact they have a thicker tip providing a better spark, however they dont last that long.

his point is, you can have iridium plugs in your car for a long time, but over that time that just keep getting worse and worse and worse. (and they cost a lot more too.

Whereas with the copper ones, if you change them say every 10 - 15000kms (or as i do every 2nd 5k service) they keep "refilling" so to say, AND they are buggar all (bout 30 bucks for 6) in the end it will probably cost you the same amount of money for plugs, but its just that every 2nd or 2rd service you do, you are gettin a brand new spark in your engine.

anyways i trust what my mate says, and i believe it makes a lot of sense too (at first i was like "but i thought these iridiums were far superior?")

choice is yours anyways, but yeh just a little advice you can take on/shrug off

Cheers, Bradd

[bubba]

Spot on Bradd.

I have always run coppers in my RB20 and then 25/30, and also now in the Neo in my Stag.

Oh, you should always be gapping the plugs before you put them in anyway, just because they *say* they are pregapped at 1.1mm, doesn't mean they actually are..

[iamhe77]

just a lil off topic, but i will always use plain old copper ones and this is why...

as my mate, (qualified mechanic building his own rb26/30 33) explained to me one day, iridiums are good, they will last around 100 000kms which is great however, there is nothing wrong with copper ones, infact they have a thicker tip providing a better spark, however they dont last that long.

his point is, you can have iridium plugs in your car for a long time, but over that time that just keep getting worse and worse and worse. (and they cost a lot more too.

Whereas with the copper ones, if you change them say every 10 - 15000kms (or as i do every 2nd 5k service) they keep "refilling" so to say, AND they are buggar all (bout 30 bucks for 6) in the end it will probably cost you the same amount of money for plugs, but its just that every 2nd or 2rd service you do, you are gettin a brand new spark in your engine.

anyways i trust what my mate says, and i believe it makes a lot of sense too (at first i was like "but i thought these iridiums were far superior?")

choice is yours anyways, but yeh just a little advice you can take on/shrug off

Cheers, Bradd

meh.

My mate and I have the Denso Iriduim's in our Stags and they are running beautifully.

They are gapped at 0.4mm and cost $16.50 each.

They are also recommended to be changed every 150,000km's... Platinum's are 100,000kms I believe.

Sooo, Irriduim = $16.50 x 6 is $99 for 150,000km's.

Copper = $5 x 6 is $30 every 10,000kms ($30 x 15 = $450 for 150,000)

Each to their own I say.

[bubba]

0.4mm gap?!@?!

Oh and I pay about $2ea for my copper NGK's..

[wolverine]

i reckon there is nothing wrong with going either way copper, iridium or platinum.

each has it's own advantage and disadvantage.

if you are paying someone to replace coppers every 10,000km then they will prove to be quite expensive. as a DIY (allowing you value your time at $0) then coppers are possibly the best bet.

i personally doubt iridiums will actually last 150,000km AND perform at their best if you have increased the performance of your car. if you are going to check them every few years you might as well replace them at that point. i remember reading (i have no source handy, sorry) the performance is fine for at least 40,000km.

so generally i run iridiums for a couple of years and swap them out. it works out fine on the cost front and they perform identically on the street to coppers. i have used some coppers on the stagea back to back with a set of iridiums and there is nothing to separate them (using the ol' seat of the bum dyno).

my R33 was back to backed at UAS and the iridiums showed an extra 1-2kw back to back (should be on their website somewhere) but this is probably just variation in time/temp/old worn copper plugs.

[RS4StagMan]

Oh, you should always be gapping the plugs before you put them in anyway, just because they *say* they are pregapped at 1.1mm, doesn't mean they actually are..

Yeah I always check the gap before putting in, however first time I have used the Iridiums and remembered reading somewhere that that they should not be gapped down. So 1.1mm they went in, now have slight misfire at idle- 1200rpm, and thinking about gapping them down to about 0.8mm.

I used the Iridiums in this case so I didn't have to touch the plugs for a few years.

I for one have always used the coppers and gapped them down between 0.1-0.3mm less than recommended on petrol in other LPG cars, as helps with LPG (increased spark energy required for different fuel).

I suppose everybody has their own opinion and preference for platinums/iridiums or coppers based on whether they are providing the labour themselves or paying somebody else to do the job. The parts cost over 100K kms-150K kms probably works out about the same.

It takes about 2-3hrs to change plugs in these cars?

[RS4StagMan]

They are also recommended to be changed every 150,000km's... Platinum's are 100,000kms I believe.

Sooo, Irriduim = $16.50 x 6 is $99 for 150,000km's.

Copper = $5 x 6 is $30 every 10,000kms ($30 x 15 = $450 for 150,000)

Each to their own I say.

I reckon;

Coppers about $3/each is closer to the mark and should last 20,000kms

= $3 x 6 is $18 every 20,000kms ($18 x 7.5 = $135 for 150,000)

Irridium = $18 x 6 is $108 for 150,000km's.

Pretty close parts cost, however labour cost (or time for DIY'ers) is the big difference.

[zei20l]

It takes about 2-3hrs to change plugs in these cars?

if someone is charging you that much labour to do plugs, start taking it somewhere else, or learn how to do it yourself.

it didnt take me that long to do my M35 VQ25DET, and a LOT of the top of the engine has to come off to get at them.

[toddlls]

I was under the impression that the tip of the iridium/platinum plug is also coated and regapping will cause the coating to flake off, considering it is an extremely hard material small flakes can do nasty things to rings/bores etc.

Buy the correct gap & check if required, but do not regap- ultimately; its your motor so your call

I am staying with iridium-personally

[RS4StagMan]

I was under the impression that the tip of the iridium/platinum plug is also coated and regapping will cause the coating to flake off, considering it is an extremely hard material small flakes can do nasty things to rings/bores etc.

Buy the correct gap & check if required, but do not regap- ultimately; its your motor so your call

I am staying with iridium-personally

Straight form the horses mouth, NGK website Australia;

" It is possible to adjust the electrode gap on precious metal spark plugs using an appropriate method that will not place any force on the centre electrode tip"

http://www.ngk.com.au/sparkplug_tech.php#

So I guess it is allowed and possible as long as you do not damage the centre electrode in any way while setting the gap.

[RS4StagMan]

if someone is charging you that much labour to do plugs, start taking it somewhere else, or learn how to do it yourself.

it didnt take me that long to do my M35 VQ25DET, and a LOT of the top of the engine has to come off to get at them.

I do all the work myself.

It's similar with the RB25DET NEO engine- a lot of items have to come off to get to the plugs. Also I have some LPG control gear under the auxillary engine cover tucked away that needs to be removed and refitted as well so for me probably closer to 3 hours.

[QWK32]

lol, so i guess banging it on a brick wall until you get the gap you after is ok then

[zei20l]

hahaha i just tap mine on the concrete floor!!