Ruthenium Spark Plugs

[3Phase]

So there I was, chasing rabbits down rabbit holes and I bumped my head on Ruthenium spark plugs.

I know, it is quite shocking is it not?

Except for the absolutely insane price tag, the consensus appears to be that Ruthenium is better than Iridium and fairly close to straight Copper for spark and flame front but with a 100K+ lifespan.

I don't believe the 100K 'span for a skinny minute but the spark plugs are spec'd for motorcycles with a 0.7 to 0.8mm spark gap.

http://ngksparkplugs.com/en/products...um-spark-plugs

Now for the fun part because NGK's Ruthenium spark plugs come in an HX and an RX series.

I think that both the HX FR6BHX plugs and the RX BKR6ERX plugs use the PSPE instead of the DFE.

[cajun31]

First observation is the fact that those don't have removable nuts and the price.

[3Phase]

Yeah, I got rid of the forked spark plug ends a long time ago and crimped the standard ends on the plug wires so I can use any plug, any time.

I did mention the insane price and Ruthenium is orders of magnitude less expensive than Iridium.

Prices today on 12 December, 2020:

RUTHENIUM USD/Oz

$280.00

IRIDIUM USD/Oz

$1700.00

They're totally ripping people off for Ruthenium.

[Bonz]

The only difference I noticed other than "Ruthenium" is the ground electrode is made of platinum versus nickel. Could that explain some of the price with the size of the ground electrode being fairly large?

[3Phase]

Depending on which version of the plug you get, only the 'point' or the 'plate' welded to the ground strap is platinum.

The RX and HX versions that might work for the XS1100/XJ1100 appear to use the platinum 'plate' but there's no way there is $12 of platinum or more per plug, they're just insanely overpriced because new.

[Bonz]

Agree. So on the underside of the side electrode there's a plate where the spark arcs across to?

This fall I changed spark plugs in my daughter's Nissan Juke. Had a coil pack go south so changed them when I was replacing that. We had bought it used and these appeared to be the original plugs. They all had a dimple underneath the side electrode where the spark would arc. What's the purpose of that type of design versus the standard side electrode? Doesn't seem to serve a purpose to me and replaced them with Autolite iridiums. Running like a champ.

[3Phase]

Heh, I have no idea about dimples, Howdy Doody.

The literature says the Ruthenium plugs use the platinum shield instead of just a point on the ground strap for the higher temperature and performance applications.

The combustion chamber temperatures in modern emission-controlled engine that the engineers would consider 'high' today and design a Ruthenium spark plug to live in are still a lot lower than they are in engines from the days when the XS1100/XJ1100 engines were made.

It would be totally not amusing if the little platinum plate went sailing out the exhaust port during a hard run or the Ruthenium cooked off.

I have to get some new float needle valve assembly o-rings from NAPA, I'll see if they have any Ruthenium plugs while I'm there.

[Bonz]

It would be cool to get a visual on the “new” style plugs.

[3Phase]

Sadly, there are no Ruthenium spark plugs in stock anywhere, they're special order because they're to expensive.

I did pick up four new float valve needle seat o-rings from NAPA for less than two dollars that are slightly thicker but they do work with a little lube and some patience without slicing the rubber.

The NAPA o-ring is on the left in the picture, the Yamaha o-ring is on the right and it beats five or six bucks -- each -- for Yamahas o-rings.