I have a mk1 1.8 Eunos…need to replace plugs(looks like last owner not serviced for years!!) will be replacing with NGK but is it worth the extra running Iridium Plugs, anyone noticed a difference from one to another?
Click on the link below put your car details in and hey presto but they are expensive
Alan
Or follow this one, and we aren’t expensive (well it depends on what you go for, but we can be about half the price of some places)
http://www.opieoils.co.uk/c-342-car-spark-plugs-glow-plugs.aspx
You pay the members prices and enter the code MAYOFFER for another 15% off
Why do you want to fit iridium plugs?—
Standard NGK sparks are very good, Iridium sparks are very good (I like em) but the best seem to be these
Any reason why those are the best? Is it just what they say on their advert, or is there any proof? The text on that advert is just like pretty much all American advertising, just OTT and that would put me off them.
Hi Oilman, using silver makes sense as it is the best electrical conductor generally available and is pretty soft. Iridium is known to be quite brittle, a couple apparently have “blown”. Platinum is a harder wearing metal but expensive and not as good a conductor. Copper is very similar to silver and cheaper so most companies use it as standard.
I’ts just stuff I remember from school and what I’ve learnt as a goldsmith 
Doesn’t mean to say the manufacturing of those silver plugs isn’t Cr@p 
All a spark plug has to do is ignite the fuel. If cheap spark plugs do this already why change to something more expensive?
If the dead posh super spangley spark plugs made any real difference to how the fuel ignites you’d have to retard your timing when you fitted them.
The only reason for fitting more expensive plugs is if they last long enough to save you having to buy more cheap ones.
I have heard of the tip breaking off an iridium plug, but I’m really not sure how often that can happen. If it was even close to a regular occurance, the plug manufacturers would have gone out of business or at least stopped using iridium. The people that mention that to me never seem to know of someone it happened to, they’ve just always heard of it from someone who knows someone, who once saw it on a forum and so on and so on. We sell loads of iridium plugs and no one has said a plug from us has broken. Also, if one did break, were they using the right plug at the time?
In most standard cars iridium plugs are no real advantage, except they last a lot longer. They become a much more sensible option in modified cars where the standard copper plugs can’t cope with the harsher conditions in the engine.
My Denso iridiums did 55,000 miles (supposed to be good for 80,000).
I got bored one day and fitted a new set I had handy from the last OZ visit (type unavailable here).
The old ones still work perfectly well & are now languishing in a cardboard box in the garage. You can keep cardboard boxes in the garage here without getting a single red-back! 