So. Changed my spark plugs last week. Car is at 88K and almost 11 years old so I figured it was a good idea despite some dissenting opinions in some of the (very entertaining) threads I've seen on CL about changing plugs.

After driving a week or so it seems the car is running just a little more frisky than before. In the past I've really only gotten the traction control light to come on the dash when on loose pavement, but a couple times since changing the plugs, I've goosed it hard while making a turn and the light has come on as the car tried to break loose a bit. Also the idle seems smoother when I'm in drive and stopped. Nothing earth shattering, but I do think there's been a slight change.

Judging by the pic of my old plugs below should I have expected any effects like this? It seems like they look pretty good to me but I'm not a spark plug reading expert by any means.

 

Interesting.
Mine is at 204K kms, on original plugs, from what I can tell.
Perhaps I should perform the same experiment.

 

Yes, total placebo effect...those OE spark plugs would have given the same performance as those brand new ones at 3 times 88k miles...

 

It's good that you did it and have piece of mind.
Those plugs look as good as new plugs with 5K mile on them.

 

So its a conspiracy from the "StealerShip" to changing the plugs?
No benefit short or long term for doing so?

 

Benefit? Ha! Zero, nada, naught, nothing, none, zilch, zippo, zip - short- term - - long-term - - for doing so at any time in the next 200,000 miles plus, plus, plus.

 

Oh boy. Looks like this thread will be merged soon.

I'm glad to have done it because I know it's done and that's one part of the car I need not worry about for a long time.

 

Don’t start new spark plugs and transmission fluid threads 😄 🙏

 

Or oil choices. That's a religion right there.

 

I've replaced plugs on older high mileage Lexus and other cars like yours many times. I'm not saying change them every 25k. Looking at plug tips gives you partial info. It results in saying the tips look ok. That's all. Inside that ceramic top are very fine wire coiled windings that generate the voltage. At only 2000rpms the plugs fire about 500 times per minute. Looking at the outside tip only to determine a 100k miles plug is ok and just as good as a new one, is like trying to look at a 10+ year old amp capacitor prongs and declaring its still preforming up to and within spec with testing it to determine the current values. Ignoring that the values mainly are based on the cap body substances effectiveness.

When I see some of the comments here on replacement matienence and feedback from those who performed the matienence changes there is a lot of "will not change anything" comments, and "no need to". I also find it odd that those who post no need to also post Lexus knows best, but then do a 360 from Lexus knows on the Lexus recommended plug replacement. Strange????? I find your thread particularly interesting because you commented of the feeling and experience you have of you own car and you would know better than anyone else. To go a step further, is the question of how those who Do Not do these services like this plug change, could tell the difference if you did not do it to experience anything at all? I normally just conclude that yes it's true, if you have not done it it's not possible to tell any difference. lol!

My experience every time I have done a plug change with new plus on a Lexus with say 75k or more I have noticed the difference in slight fuel economy, and responsiveness. Even to the point that a week or a few days later forgetting I replaced the plugs something reminded me of it by the difference in the way my Lexus felt in engine performance. With that, my response to you is... you feel what you feel, and no you can't compare what those who have and, do not. Compare you car, not band wagon Narratives here.

 

Much appreciate your perspective and your thoughtful response.

 

You do realize your math is off by half. A 4-cycle engine spark plug fires once every other engine revolution. At exactly 2,000 RPM, each plug is firing exactly 1,000 times per minute, not 500. Also, the spiral isn't inside any plug I've ever broken. It is a solid core, usually copper with a coating of some other metal with a tip that may be of a more exotic metal, like iridium, etc. The spiral is usually in the plug wires if it has wires, as opposed to Coil-on-Plug, to reduce radio interference.

Plugs are the most basic part of an engine with no moving parts and no electronics. The tip and electrode, barring any physical failure in sealing or electrical insulation, is the only part of the plug that sees combustion. The only thing that matters is ensuring there is adequate gap to produce the planned spark. If the new plugs are pulled after a few 1,000 miles, they will look like the plugs displayed currently at 88,000 miles. The lack of lead in fuels and the efficiency of new fuel delivery systems has essentially eliminated the causes of plug fouling in a properly functioning engine.

Coil packs will make WAY more difference than the plugs though modern ignition systems deliver more energy than previous generations that used a single coil/distributor system. Sure, you can find a dyno run that shows 1HP gain with new plugs but 1HP in a 300HP engine is less than the margin of error in measuring. You can change nothing and get larger deviations with almost any engine on any dyno.

 

My statement was about a average general engine firing. Point was a lot. Do you know how many times the exact number is for the 6 cylinder 2GR? My point was plugs work hard in the line of fire, and fire a lot per rev, is all. You can find many dyno, 0-60, mpg and other measures googling that show the improvements by many reputable automobile sites that don't sell anything. I think you did another thread where you thought your clock stop working due to a oil change you did. So we have all been off being human but again It was a general statement about how hard plugs fire is all.

My choice of the plug that I use is the NGK, for personal reason and mods to my own 2GR. Most of the Iridium plugs are confirmed to have construction design with a spark plug design that do typically have very thin wire center fine wire winging center as I stated in my 1st post.

I can dig up a previous plug thread here on CL where you replied to me before stating that you had a GM LS1 motor, and at the track you ran faster with putting back in your old plugs than you did new plugs. I told you before I would love to get the LS1 forum members thoughts on this? There are also threads that you stated coils packs would make no difference so I find the statements very hard to understand?

I often get the feeling that lots are just so amazed at the Toyota developed engines. Yes they are that good that you can run oil changes to 15k, change the Air filter every 5 years, keep the original plugs in there to 300k, use 87 fuel and never do any Upper Intake and combustion cleaning of any sort and/or other maintenance. Due to modern advances in the ECU adjustments, it will continue to run yes. If it is all one cares about for the things you own, I have no problems with it, it's your car. The just put gas in forget about it and go crowd for your, car is ok with me, I have no problems with it. lol! I was mainly responding to the op who made the change and would be most qualified to say what he thought vs, those who have....not and, the no need to - Narrative.

 

It is simply math for a 4-cycle engine. Cycle/2=Firing Events per cylinder. It is half any RPM per cylinder.

That was my attempt at humor. I guess you didn't get it.

Not according to NGK themselves.


You clearly have me confused with someone else. I've never owned an LS engine in any vehicle in my life. However, IF a person selected the wrong NEW plug and the OLD plugs weren't fouled, it is possible though.

 

I'll let it go but.... I think there is a spin in descriptions. When I said, center I was describing Core materials.

https://www.oldcarsweekly.com/review/spark-plug/

At the top of the list, we have the NGK Spark Plugs. With iridium as its core material, this spark plug pack can operate at a much wider heat ...

Copper is a great electrical conductor with low resistance.

Almost all spark plugs use a copper cored center electrode to conduct the electricity, jump the gap, and promote heat dissipation. Due to its soft nature and low melting point, using copper as an outer electrode material would result in a plug that lasted only minutes.

"Copper spark plugs" is a term mistakenly used for a standard or traditional spark plug. A standard spark plug typically uses a nickel-alloy outer material fused to a copper core. Some plugs include a coating or pad of precious metals to extend plug life. But as a general rule of thumb, all spark plugs utilize a copper core.




Iridium is 6x harder and 8x stronger than platinum, has a melting point 1,200°(F) higher, and conducts electricity better.

For many years, spark plug manufacturers favored platinum for their long life and performance plugs due to its high melting point. However, increasingly strenuous engine conditions, and the creation of smaller electrodes and longer life plugs required harder and stronger metals. The strength, hardness and high melting point of iridium makes it very well suited for a fine wire plug and ultra long life spark plugs.

Though better than platinum in these respects, it is very expensive, and at higher temperatures it oxidizes, thus rendering pure iridium as an expensively poor choice for spark plug construction. However, when properly blended with other precious metals such as yttria, rhodium or platinum, you can enhance their advantages with the superior strength and hardness of iridium.

The price point of an iridium plug is usually equitable to its iridium content. Some lower priced iridium plugs have just enough iridium content to be marketed as iridium plugs. They likely will not perform or last as long as the plugs with a higher iridium content.

BTW: My mistake for some reason I thought I remembered it being a LS1 engine. End of post #25 below.

https://www.clublexus.com/forums/gs-...l#post11241150



Just to repeat again.... I was directly responding to the op of the thread. Every time someone comments they changed their plugs here they get the "Narrative" in spite of the Lexus GS350 service recommendation to do it.