Iridium sparkplugs?

chevrolet
1500
sparkplugs

#1

Are they worth the extra cost?


#2

If there’s easy access to the spark plugs they’re not worth the money. These exotic metals are used on spark plugs are for longer life of the spark plug. So if access to the spark plugs is hard you use these type of spark plugs. Otherwise, platinum plugs are good enough.

Tester


#3

Yes. They’re Factory Issue In My Bonneville And They Work Well And Last A Long, Long Time. If That’s The Original Equipment Plug Then Put Them Back In There. Otherwise Use What Was Specified Originally.

CSA


#4

If you are looking for improved performance or better fuel economy, you will not get it by paying extra for exotic spark plugs. If your spark plugs are really buried and you don’t ever want to have to replace them again, they might just be worth it. Platinum plugs are plenty sufficient for most people. I have replaced platinum plugs that had over 100k miles on them and they still looked like new. I say for your Silverado 1500, use whatever the factory specified, even if it calls for copper core. I can’t think of a single Silverado with difficult to change spark plugs.


#5

Use whatever was in the car. I just replaced mine at 68K and they hardly looked worn at all. I expect either I or the car will be dead before I have to do it again. One thing though is don’t set the gap. They come factory set and they are too brittle to mess with the gap.


#6

Unfortunately many manufacturers are now making them standard. For my wifes Lexus…Iridium are the only plugs available…And as of last year…Denso was the only manufacturer.


#7

Put In The Plugs That The Manufacturer Specifies. As I Said Earlier, My Bonneville Specs AC Delco #41-101 Iridium Spark Plugs. I Paid 6 Bucks Each For Them At Advance Auto Last Fall, Not A Big Deal Every 100,000 Miles.

After 100,000 miles the business end of the plugs still look new.

CSA


#8

Iridium does not react with Nitros used for street racing. Platinum does react to nitros and they get ruined. Iridium is not needed and costs way more than standard plugs. Buy the ones that came with the truck and save your money.


#9

Hello,
I am the tech manager at Autolite spark plugs. Alot of misconceptions about iridium spark plugs on this forum. Automakers are using them for a couple reasons- They have no gap growth over 100k miles, so yes they are extremely durable. They are benefits to using them in any car. They use less voltage to fire, amek a larger flame kernal in the combustion chamber and actuall burn more of the fuel that goes through the engine.All real benefits based on technology, not gimmicks. Believe me, automakers never want to pay more for any part, when they do it is because there is a real performance benefit.


#10

Autolite has iridium spark plugs for your lexus.


#11

They have no gap growth over 100k miles, so yes they are extremely durable.

Have you ever tried removing a spark-plug that’s been in an engine for 100k miles??? I’ve done it once and won’t do it again…Of the 6 plugs removed…two had to be helicoiled (especially dangerous with aluminum heads).

A lower voltage and higher flame does NOT mean better performance or better gas-mileage…nor does it mean it’ll burn more fuel.

Believe me, automakers never want to pay more for any part, when they do it is because there is a real performance benefit.

The MAIN reason is because of longevity…PERIOD…Performance - Marginal at best.

As for Auto-lite plugs…While I never had a problem with Fram filters…I’ve had MAJOR problems with Auto-lite plugs…They are by most people I know to be the low-end of the low-end plugs. If you want the cheapest plugs available and don’t car about your car…buy Auto-lite…The difference between Auto-lite plugs and NGK is about the same as a Rolls Royce and a Pinto.


#12

Seeing as how Motorking is now a tech manager for Autolite spark plugs and recently posted as a tech manager for Fram filters I’m of the opinion that Motorking is actually a PR department flak for Allied Signal.

I also think some of the tech info Motorking posted is not correct. (Regarding plug gap consistency, less voltage to fire, burning more fuel through the engine, etc, etc.)

As to spark plug durability about the only plugs I’ve used over the years (my vehicles and all others) were Autolites, NGKs, and Bosch. I’ve seen very very few problems with any of those brands.


#13

As to spark plug durability about the only plugs I’ve used over the years (my vehicles and all others) were Autolites, NGKs, and Bosch. I’ve seen very very few problems with any of those brands.

You’ve had more experience with them then I have…I’ve used Autolite twice…and both times had problems…Vehicle didn’t run right. Never used Bosch…always found them too expensive…NGK…since they’re the OEM provider for most of my vehicles…these always seem to have worked the best.


#14

“I also think some of the tech info Motorking posted is not correct. (Regarding plug gap consistency, less voltage to fire, burning more fuel through the engine, etc, etc.)”

My BS alarm went off when I read that too…Do we really need 20,000 different spark plugs to serve IC engines??? I mean, aren’t all spark plugs pretty much the same?? Do the same job? Why do they need 20,000 different ones?? Shelf Space…


#15

I recommend using the same plug the engine came out of the factory with.

My current car uses iridium plugs and there’s no way I’ll leave them in for 100k miles.
I’m pondering whether to take them out at 30k or 60k to look them over and put a fresh coat of anti-seize on the threads.


#16

It does not take less voltage to jump a .32" gap in a given fuel mixture if the electrodes are irridium rather than platinum. The gap size, the mixture, and the mixture density determine the voltage required. Compression is a factor in the mixture density, as is the density of the mix that comes in through the intake valve.

In plugs with 30,000 miles on them, it perhaps does take more voltage to fire a platinum plug than an irridium plug, only because irridium does not evaporate (erode) as readily with arcing. Irridium can therefore maintain a more consistant gap and a more consistant spark over a longer period, allowing them to be changed less often and, I’d argue, making the engine run clean and more efficient for longer durations. This does lead to more reliability and less pollution long term.

However, I’ve always believed in staying with the manufacturer’s recommended plugs for stock engines. While a plug manufacturer may list both platinum and irridium, and both may be physically interchangable and have the same heat range, the proper one ensures that no anomolies due to some suttle difference.


#17

“It does not take less voltage to jump a .32” gap in a given fuel mixture if the electrodes are irridium rather than platinum."

It makes a difference if the electrodes are more “pointy”.
This is covered in college level electromagnetics.
A smaller radius of curvature creates a higher gradient in the electric field.


Platinum v.s. Iridium
#18

I agree that 100K is too long. Plugs can get stuck. And i guess I live by the philosophy that doing maintenance before it’s required rather than wait until it’s required is a key to longeveity. Sort of like exercising and eating right before your first heart attack rather than after.

I generally recommend not reusing plugs. Many todaym those with the “flat base”, have metal compression washers on them that are designed for only one application. Once crushed, it’s not recommended that they be resused. Since I know you realize this, the comment is posted for the consumption of those forum followers who may not.


#19

It does not take less voltage to jump a .32" gap in a given fuel mixture if the electrodes are irridium rather than platinum.

A couple of pertinent considerations; work function and thermionic emission. Both will impact the emmissivity of the electrodes. Iridium has a lower work function than platinum. The smaller electrodes and their material can/do run at higher temperature and therefore increase their ability to emit electrons. This lowers the apparent dielectric insulation of the gas. The working voltage can be lower for those reasons.


#20

Points made, guys. I stand corrected.