OE spark plug question

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Originally Posted By: BigCahuna
Since no auto mfgr actually MAKES spark plugs, No one can prove they are the best. Harley plugs are a classic example. They're made by Champion, who also sells a plug that looks exactly the same, without the Harley name on it for less $$$. With the way cars are made these days, computers control every aspect of ignition. A super duper factory trained tech could not tell just from driving a particular car ,what plugs are installed in it.Use whatever brand you want, as long as the plug mfgr says it's for your vehicle. And change them every 50-100k miles.,,


No one is suggesting that vehicle manufacturers make their own spark plugs, but each car rolls off the assembly line Originally Equipped with plugs by a particular Manufacturer (OEM). Engines are engineered around a particular spark plug with very specific attributes, and sometimes changing brands results in less than ideal operation. The two most important attributes being heat range and reach.

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Stick with oem brand, but feel free to upgrade electrode material. If you have waste spark ignition you will need double platinum or double iridium.

Sometimes when switching brands, there is something lost in the translation resulting in a hotter or colder plug. This can cause a miss or detonation.


VQ engines are a good example. They were designed around NGK plugs, have read numerous anecdotal evidence of fellow members at Maxima.org that have tried running Bosch plugs just to get misfiring a couple hundred miles later.

Almost all plug manufacturers are "good", however a brand that works good in one car, won't necessarily work good in another. Bosch in Euros, NGK in Asians, AC Delco (Often made by NGK) in GM, Autolite in Ford, etc..

Cliffs;
OEM means Original Equipment Manufacturer, not Vehicle Manufacturer. Stick with recommended OEM plugs for best performance.
 
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Originally Posted By: ARCOgraphite
Most all plugs are Copper - including Pt and Ir plugs. Typically, standard economy GND wire and center conductors are Inconel alloy (or similar) at the firing electrode tip(s) only.


Yeah I know that. Last copper plugs I used were non resistor as well.

Long life plugs I beleive are mostly the result of emissions requirements, and vastly improved ignition and fuel injection systems.
 
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Originally Posted By: asand1

OEM means Original Equipment Manufacturer, not Vehicle Manufacturer. Stick with recommended OEM plugs for best performance.


....except on Ebay and Craigslist where MANY items listed as OEM are in fact OEM-COMPATIBLE...(if that's good enough for ya)...steals of the day...
 
Originally Posted By: KitaCam
Originally Posted By: asand1

OEM means Original Equipment Manufacturer, not Vehicle Manufacturer. Stick with recommended OEM plugs for best performance.


....except on Ebay and Craigslist where MANY items listed as OEM are in fact OEM-COMPATIBLE...(if that's good enough for ya)...steals of the day...

And if you go to Advance Auto, they have a product line called OE Brand which you should avoid. It is simply a cheaply made part.
 
Originally Posted By: jorton
Do I have to replace spark plugs with OE parts?

Nickel alloy electrode wears fast. The other car has the same type COP ignition and OE parts are platinum. Platinum electrode wears longer. If I decide to run platinum plugs I will still change them at manufacturers 32,000 miles intervals.

I would use the OEM plugs. Even if the OEM manufacturer makes platinum or iridium versions of the same plug, OEM plugs get slightly more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops.

Also, for an old car, the service life will be determined by oil-ash fouling, not electrode wear. That defeats the purpose of getting a platinum/iridium plug.

Simply change the OEM plugs every 30k or so.

I personally prefer Denso over NGK.
 
"more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops."

Can't argue with that, especially in this vehicle. Thanks for the spark plug lesson!
 
Originally Posted By: jorton
"more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops."

Can't argue with that, especially in this vehicle. Thanks for the spark plug lesson!

Sure, after checking the link you have, yours don't seem to be the U-groove (DENSO) or V-Power (V-groove) (NGK) type, but nevertheless, I expect the OEM plugs to still perform better. They would be less prone to oil-ash fouling thanks to having much larger electrodes than platinum plugs. As long as they are replaced according to the recommended interval, they should be OK.
 
Originally Posted By: Gokhan
Originally Posted By: jorton
Do I have to replace spark plugs with OE parts?

I would use the OEM plugs. Even if the OEM manufacturer makes platinum or iridium versions of the same plug, OEM plugs get slightly more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops.

Also, for an old car, the service life will be determined by oil-ash fouling, not electrode wear. That defeats the purpose of getting a platinum/iridium plug.

Simply change the OEM plugs every 30k or so.

I personally prefer Denso over NGK.

From your experiences should the first set of factory fitted spark plugs be changed at somewhat earlier than this 30k mile interval (approx 20-25 k miles), and thereafter the spark plugs should be changed at 30k miles intervals ?
 
As said, almost always, the OEM plug is optimal. In some, the engine won't run right without the OE plug, like the five cathode made-in-France plug specified in many NA Volvos. Most of the time the OE plug is not much more anyway (although a set of 5 Volvo R plugs is now over $70 - ouch).

But there are occasionally exceptions to the rule, typically with much older engines. On the water, we found that regular copper core NGKs held up much better than the OEM ACs and everything else, including fancy-pants platinums, on some older GM gassers, where its spinning WOT all afternoon long.
 
Originally Posted By: fpracha
Originally Posted By: Gokhan
Originally Posted By: jorton
Do I have to replace spark plugs with OE parts?

I would use the OEM plugs. Even if the OEM manufacturer makes platinum or iridium versions of the same plug, OEM plugs get slightly more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops.

Also, for an old car, the service life will be determined by oil-ash fouling, not electrode wear. That defeats the purpose of getting a platinum/iridium plug.

Simply change the OEM plugs every 30k or so.

I personally prefer Denso over NGK.

From your experiences should the first set of factory fitted spark plugs be changed at somewhat earlier than this 30k mile interval (approx 20-25 k miles), and thereafter the spark plugs should be changed at 30k miles intervals ?

You mean because brand-new cars consume oil during break-in?

That's usually only about a quart of oil at most. Therefore, I think 30k miles with a quality OEM plug should be OK even when the car is new.
 
Originally Posted By: Volvohead
As said, almost always, the OEM plug is optimal. In some, the engine won't run right without the OE plug, like the five cathode made-in-France plug specified in many NA Volvos. Most of the time the OE plug is not much more anyway (although a set of 5 Volvo R plugs is now over $70 - ouch).

But there are occasionally exceptions to the rule, typically with much older engines. On the water, we found that regular copper core NGKs held up much better than the OEM ACs and everything else, including fancy-pants platinums, on some older GM gassers, where its spinning WOT all afternoon long.

Ditto on NGK and Nippondenso. I'm more a fan of Nippondenso than NGK though, but Nippondenso is harder to find.
 
I am surprised that there is no spark plug information on 2012 Acura TL under hood. I thought that was mandated by emissions.
 
Originally Posted By: jorton
"more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops."

Can't argue with that, especially in this vehicle. Thanks for the spark plug lesson!


The Denso U and NGK V Power is just helping to maintain ignitability compared to standard plug, however this pales in comparison of latest iridium plug (NGK IX/IX-P, Denso SIP,VK/IK, Bosch OE Iridium) which use thinner center electrode to maintain ignitability.

Some people do not realize, the wrong heat range of plug also can increase fuel consumption on top of the carbon issue. The best plug is the SIP plug but unfortunately it does not cover much old engine model, and the most important to check is whether the car has wasted spark iginition which warrants dual iridium or iridium-platinum for both plug tips to have long life. The downside of platinum is the size can not be made as tiny as iridium to have same durability, that will cause less ignitability capability compared to iridium.
 
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Originally Posted By: kr_bitog
Originally Posted By: jorton
"more gas mileage and horsepower because they employ a U ground-electrode groove (Denso) or V inner-electrode groove (NGK), which increases the combustion efficiency by trapping a small amount of mixture where the spark develops."

Can't argue with that, especially in this vehicle. Thanks for the spark plug lesson!

The Denso U and NGK V Power is just helping to maintain ignitability compared to standard plug, however this pales in comparison of latest iridium plug (NGK IX/IX-P, Denso SIP,VK/IK, Bosch OE Iridium) which use thinner center electrode to maintain ignitability.

Some people do not realize, the wrong heat range of plug also can increase fuel consumption on top of the carbon issue. The best plug is the SIP plug but unfortunately it does not cover much old engine model, and the most important to check is whether the car has wasted spark iginition which warrants dual iridium or iridium-platinum for both plug tips to have long life. The downside of platinum is the size can not be made as tiny as iridium to have same durability, that will cause less ignitability capability compared to iridium.

I don't completely agree with the assessment regarding the super-ignition plug (SIP). The SIP plug compromises between plug durability (120k miles or longer) and ignition capability.

On the other hand, the V or U grooves are all about ignition capability but not about plug durability at all. I believe it's possible to generate a larger-diameter initial fireball between the groove and opposing electrode than with an SIP plug, which tries to increase the size of initial fireball diameter by reducing the quenching effect by making the electrodes thinner but doesn't add extra distance for the initial fireball to grow as in a groove plug.

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U-groove and conventional plugs: in the U-grove plug, there is more distance for the initial fireball to grow than in the conventional plug.

2qLh1axviHY.jpg

SIP plug: electrodes are thinner for less quenching of the initial fireball but the distance for the initial fireball to grow is unchanged from the conventional plug.

Long story short, OEM U-groove or V-groove plugs work as well and probably better than the fancy, expensive plugs, as long as they are changed with the recommended interval.
 
Originally Posted By: Vikas
I am surprised that there is no spark plug information on 2012 Acura TL under hood. I thought that was mandated by emissions.

I'm used to not seeing spark plug info on cars made in the last 10 years or so.

However, I am used to seeing part numbers in the owner's manual. In many Japanese cars, I would usually see 1 NGK part number and 1 Denso part number. NGK plugs were always easier for me to get, so I saw zero advantage to finding Denso plugs.

The second problem with having a part number underhood or in the manual is what would happen if a TSB called for a different kind of spark plug? I have worked on multiple cars where the exact OEM plug would be discontinued, and a different plug was required.
 
Originally Posted By: Gokhan
Originally Posted By: fpracha
Originally Posted By: Gokhan

Simply change the OEM plugs every 30k or so.

From your experiences should the first set of factory fitted spark plugs be changed at somewhat earlier than this 30k mile interval (approx 20-25 k miles), and thereafter the spark plugs should be changed at 30k miles intervals ?

You mean because brand-new cars consume oil during break-in?

That's usually only about a quart of oil at most. Therefore, I think 30k miles with a quality OEM plug should be OK even when the car is new.

Yes because there is a chance for improved fuel economy when changing the first factory installed set a little earlier. Or is this totally flawed logic ?
 
The factory installed Denso iridiums' lifetime is 120k miles on the Camry....changed mine @ 100k and they looked just fine....still, that's after 8 years....another 2 years might make them harder to remove...no change in performance with the new ones..
 
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Originally Posted By: KitaCam
The factory installed Denso iridiums' lifetime is 120k miles on the Camry....changed mine @ 100k and they looked just fine....still, that's after 8 years....another 2 years might make them harder to remove...no change in performance with the new ones..


That's a really good point.

Sometimes it's good to change them just to keep them from freezing up in the head.

That one has bitten a lot of Ford truck owners in recent years.

Anti-seize helps, but exercising the threads periodically works best.
 
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That one has bitten a lot of Ford truck owners in recent years.
However, please don't use that example as that plug left had wrong design to begin with. I have taken few NGK off vehicles at 10/150K without much protest.
 
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