I have been told that the iriduim spark plugs I was running were "too hot" and I should revert to the platinium ones. can any one please explain this to me please? .

I have moved back to the platinium ones and my car is running well with current set up. But I thought the smaller hotter start to the flame in the power stroke the better!

Thanks !

 

Hmm, interesting comment from whoever that was...

Iridium - platinum - Copper - Unobtainium, it doesnt matter what the plug material is, it doesnt significantly affect the heat range of the plug itself, all it does is improve spark and or reliability / longevity. the plugs still conform to heat ranges as plugs always have.

Its true you may have fitted a plug too hot for your engine, no argument there, but choosing a correct range Iridium is the same solution as fitting the correct range platinum, so if you were told all Iridium are too hot for your engine then the guy who told you that is totally and utterly wrong.

If your interested in spark plug technology, this may prove an interesting read for you.

http://www.motorsport-developments.c...AF272_tech.pdf
Pop the kettle on.

 

What iridium plug were you on, and what platinum plug are you on now instead?

 

sorrry about the delay in getting back but family and looking fir work too me away from passion ford!

I have done some digging in my garrage and other sotres and found:

old spark plugs:

platinium AGPR12pp - as per ford parts dept!
platinium AGPR902p - as per ford parts dept!

Iridium IK20 - as installed by me after going Denso web site.

Iridium IK24 NOW installed in the car.

so can you tell me whick ones were right?

Many thanks

Brendan

Engine is Turbo'd CVH running 14 to 16 PSI boost, bosch beige 701 injectors, water cooled valve guides to keep the head cool.

 

Not sure which are right for your car but personally i'd take the denso one's and launch them straight in the bin

 

why don't you like the Denso spark plugs? Iridium ones will probably be the better as Iridium is the only metal to maintain good mechanical properties in air at temperatures above 1600 °C.

platinium can't quite match this! and its cheaper too! Iridium is even more dificult to machine too!

 

Ive had NGK iridium plugs in my cossie for nearly 4 years nw and they have been spot on.

 

Because it was a denso plug that dropped on end of into my engine mashing it up

I've been told/read that this has happened quite a few times to people running denso plugs, from what i've read/heard most people stay clear of them now

 

Doeas any one know the NGK equivilant for the IK24 spark plugs?

 

Usually bits fall off plugs through physical abuse, or detonation etc

I would only ever use NGK or Denso. Never had a problem with either.

 

Interesting enough- i had a road rally rs 200 mk2 few years back that had 4 different plug values in it when set up by paul goy racing in lincoln,(ANYONE KNOW THEM IM NOT SURE IF THEY ARE THERE ANYMORE)each cylinder was a different temp so to conmpensate -hence the plugs

 

Agreed, the Iridium killers in order:

1. Overtightening.
2. Dropping before fitment. (Or before purchase maybe?)
3. The use of copper grease on threads.

 

I'd personally bin the platinum/irridium and stick in a set of copper NGK BCR 8ES. Just because they cost a tenner, doesn't mean they are shite/worse than an over priced set of irridium!

 

Quite true. If the ignition system is up to scratch, it's hard to beat cheap copper plugs. And it isnt as if Cossie plugs are hard to change necessitating precious metal longlife plugs.

 

I got a sykes picavant spark plug wrench for christmas! so over tightening them won't be an issue when I check on them! I don't use copper grease for the threads, and won't even think about after stu's comments. does any one have any info on what the numbers and letters mean for the temp of the spark plug

 

never use copper grease on any plug it can hinder the plugs ability to transfer heat to the head properley

 

Im impressed... not many people know that.

 

No its not, but the engine does have an issue burning weak mixtures at low speeds. P + I plugs help this immensely.

 

I wont argue that they may help if the ignition system is below par.

With proper coil/coils, they'll light up pretty much anything with a bog standard copper plug

 

I thought the Idea behined Iridium spark plugs is that they can have a smaler and therefore hotter point to start the detonation of the fuel air mix? This is normally more effective.

 

well today ive learnt something new, thanks for sharing that bit of info with us,

i have always used copper slip on the plug threads in the past

 

Does this apply to CVH's as well Stu (as this is what the OP is asking about), and what P or I plugs would be the correct ones for a turbo CVH?
If P or I plugs means I can run a slightly leaner idle/cruise thats very handy

 

I thought the correct ones for a cvh turbo were ik24 karlos which is what i have in mine at the moment

 

That is whats listed on the Opie site yeah, but just wanted to get the opinion of a tuner and also if the CVH suffers the same issue as the YB.