Iridium spark plugs

[rbmatthews]

Our new(ish) Mariner Optimax has iridium spark plugs (NGK IZFR5J) which I have just discovered cost around £20 each!

Wanting to buy a spare set for emergencies, I am a bit reluctant to splash out £60 until I really need them, so I was wondering if there are any equivalent standard plugs that might do the job as spares, and if so, whether that is a good idea anyway? i.e. should standard plugs (if they exist) be used in that type of engine, and also is it wise to mix the two types?

Or is it just a question of biting the bullet?

The ones that I have at the moment have done about 150 hours, and I am hoping there is quite a bit more life in them yet.

 

[nimbusgb]

My Merc has 16 iridium plugs!

I don't keep a spare set. Thankfully they are expected last 50 000 miles though!

Why keep a spare set? Keep just one, usually only one plug will die not an entire set.

Chances are you can find a cheaper alternative, non iridium plug as a get you home set.

 

[penfold]

I get the impression that iridium plugs are supposed to be significantly more durable than ordinary sparklers; anecdotal comments suggest up to 10x longer life, but I've not researched the matter in any depth, just looked into it a little when looking for a new set of iridium plugs for my car. They ended up being bought in the US as they were half the price they were here.

 

[rbmatthews]

Thanks for your replies. Yes, good idea to just buy one plug.

BTW, does anyone know if these rare earth metal plugs (platinum, iridium, etc.) are recycled, or is it not worth it?

R.