Spark plug choices?!

I have fitted a few makes all listed as compatible. Bosch, nickel and iridium NGK,  Beru.
The common factors have been they all worked fine and offered no noticeable difference in MPG or performance.
As stated the only difference is expected plug life. The nickel plugs are rated for 10k miles, although they can last longer. The NGK Iridium plugs are rated for 40k plus life.  I am currently using a set of NGK Iridium plugs to see if they live up to the claim,  so can't confirm at the moment.
The Beru plugs I used are only good for about 15k miles, so not much better than the nickel plugs.
Iridium is ideal for vehicles with hard to reach plugs as there cost is offset by the labour cost to change them. This is not really an issue on a Jimny, if you service yourself every year and cover less than 10K then nickel plugs are fine. Higher milage or just a dislike of changing them makes Iridium the better choice.

 

This is why I use them. In conjunction with my k&n panel air filter and an average of a thousand miles a month it reduces my service time for intermediate services to just an oil and filter change every 9 months. The air filter has paid for itself many times over as its washable every 100k, the plugs save time and wear and tear as I'm only disturbing them every 3 years. That said I suspect even then they would probably go longer as they are always perfect when I replace them, but I don't want to risk that as you can go too far and it becomes neglect.

Great, thanks all - useful advise. I've got the filter to collect from ECP so will stuck an order in for some NGK cheap plugs just now as I have no idea when the car was last serviced.

Any ideas on my engine code from previous post? I did a bit more reading and believed the way to tell if vvt is the bump at the front left of engine as you look at it, which I don't have, so assuming it's a non vvt m13?

You are correct, you are missing the VVT bump.

OK, got me some NGK BKR6E plugs, came up on ECP under my reg and cheapest at £2.98 before discount. Guess I should double check plug gaps even though most stuff I've done in the past 20years has come pre gapped -  anyone know what they should be?

No matter, services it today and just chucked the plugs in, all running fine. Easiest car to service I've worked on in a while! Filter and drain plugs are in a really handy location, small plastic takeout box to catch oil from filter job done.

Most plug gaps are pretty much spot on these days, the vehicle manufacturer pretty much goes with the plug manufacturer's standard gap.

Just as well as on my other car the plugs have 3 cathodes arranged around the central anode, I wouldn't want to start trying to gap those, I don't think you would ever get them all the same.

I have read that NGK has an upgraded spark plug from the Premium RX to the Ruthenium HX.  I can not find a cross-reference between the two.  The specs for the Premium RX (DCPR6ERX-11P / 90558) are: Thread diameter: 12mm Thread reach: 19mm Seat type: flat Hex size: 16mm
Is there a Ruthenium HX model that matches this spec?
Or, am I way off with my understanding about these?

I fitted the Denso iridium ones.  A bit cheaper than NGK and I found a marginal improvement in mpg with them in other cars.

I don't know if Denso supply Suzuki but they supply a lot of OEM parts on Mazdas etc.

In 2021 I bought a set of NGK Iridium IFR6J11, 4 for £52 for my 2011 Gen3. I fully expect them to last the life of the car, but if they do need replacing it won't be the tip that has worn out, it will probably be oil fouling or some other type of damage.

Iridium are meant to be good for up to 100k miles.

Ruthenium tip are meant to last longer and give slightly higher performance, whilst this might be true of a modern car engine where fuel efficiency and performance is much higher I doubt it will make any difference at all to a Jimny.

The longer electrode life will be of limited benefit as something else will wreck the plugs, like oil fouling, over-heating or muck and dust on the outside so I doubt you will see any benefit.

However, see how much they are and if they are about the same price as Iridium (or cheaper) then go for it, just don't expect to notice any difference over a decent set of ordinary or Iridium plugs.

By the way I couldn't find any for sale in the UK to fit a Jimny, there seemed to be some in Japan though.

Robin

Don't overthink spark plugs. All Jimnys have very basic, low performance engines. The only benefit of more expensive plugs is lifespan, but that is reflected directly in the cost. And if you don't change your plugs for a decade, you may find them reluctant to come out which can lead to much bigger issues. I use standard copper plugs in my Jimnys. They are £20 a set and look good as new after 2 years/20,000 miles.