4 Types of Spark Plugs (Copper vs Iridium vs Platinum vs Double Platinum)

Last Updated on December 3, 2019

You might think that all spark plugs are the same. After all, the general purpose of a spark plug is to generate an electric current for igniting the compressed air and fuel in the combustion chamber.

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However, there are some differences when it comes to spark plugs. Certain ones are more efficient and perform better than others. It all depends on what type of spark plugs your vehicle’s manufacturer recommends.

All spark plugs have a central electrode and a side electrode. These electrodes were traditionally made of copper but now they are being manufactured from materials like iridium and platinum.

Also, the center electrodes are being made much smaller than they used to be. This means that less voltage will be required to generate the electric current for the combustion chamber.

Overall, you will find the four main types of spark plugs are copper spark plugs, iridium spark plugs, platinum spark plugs, and double platinum spark plugs.

Some have better uses than others, depending on the vehicle that you’re driving. Below you will find more details on these spark plugs and what they are good for.

Related: Best Spark Plugs for Gas Mileage and Performance

Copper Spark Plugs

copper spark plug

This spark plug is mostly made from solid copper. Its central electrode is made from nickel alloy and it has the largest diameter of all the other spark plugs. This means it’ll need more voltage to generate an electric current.

Nickel alloy is a material that is soft and not very durable. This means it won’t last long. It is best to use copper spark plugs in older vehicles which didn’t have high electrical needs.

  • Pros – Better for older vehicles built before 1980.
  • Cons – They don’t last as long; Requires more voltage.

Iridium Spark Plugs

iridium spark plug

Iridium spark plugs will last the longest. Iridium is a metal that is harder and more durable than platinum. Although you will have to pay more money for iridium spark plugs, you will get what you pay for.

These spark plugs have a small center electrode which means they use less voltage to generate the electric current. That is why many car manufacturers are starting to recommend iridium spark plugs for their vehicles.

If you already have these spark plugs installed and you need new ones, do not downgrade to platinum or copper because they will diminish the performance of your vehicle.

  • Pros – Harder than platinum; Lasts the Longest; Uses Less Voltage
  • Cons – Expensive

Platinum Spark Plugs

single platinum spark plug

A platinum spark plug is similar to a copper spark plug, except that its center electrode has a platinum disc which is welded to its tip area. The copper spark plug only has nickel alloy material in this area.

As a result, the platinum spark plug is more durable and can last as many as 100,000 miles.

These plugs also generate more heat, which means that debris buildup will be reduced. If you have a new car with an electronic distributor ignition system, platinum spark plugs are recommended.

  • Pros – Lasts longer than copper; Reduces debris buildup
  • Cons – Not the strongest spark plug on the market

Read also: 5 Symptoms of a Bad Brake Pads and Need to Change Immediately

Double Platinum Spark Plugs

double platinum spark plug

If your distributor ignition system is a waste spark system, then double platinum spark plugs are recommended. This system causes the spark plugs to fire twice, once in the compression stroke’s cylinder and the other in the exhaust stroke’s cylinder.

The spark for the latter gets wasted because there is no ignition there. The benefit of the waste spark system is that it is more reliable and isn’t affected by environmental conditions such as rain or dampness.

  • Pros – Recommended for Waste Spark Systems; Reliable
  • Cons – Not recommended for electronic DIS
 

Comments

    • Spark plug gap will widen over time especially in standard copper plugs. But precious metals like platinum and iridium are much harder so any wear down (which causes a gap increase) will be incredibly slow.

      Reply
  1. I put in iridium tipped NKG izfr5k11 plugs in my 2005 Honda Pilot.
    These are for 2006-08. opps. Honda direct oem matched these plugs for my 05.
    The recommended plug is platinum ngk zfr5fgp, which is what came out.
    That is why I ended up here.
    Just checking. The gap difference is .040-platinum vs .044-iridium
    I think I’m fine. your opinion?

    Reply
  2. In ancient times we used steel tipped spark plugs (at least we always called them such). We are talking Champion and Delco and Autolite, all-American plugs that lasted maybe 6000 miles before performance drop off, very common in the days of the 6k tune up interval for ANY stone ax era points-fired car. They were so-so, though when the Champion extended tip “Y” series appeared, as in J12Y for my old 60’s Pontiacs, they seemed to make a real difference, putting the spark closer to the center of the chamber a few MM and I noted better gas mileage… 5-10% on my delivery routes. Most plugs these days are extended tip and exceed our “stone knives and bear skins” era performance.

    Then I got my 1970’s UJM (Universal Japanese Motorcycle) and found a more modern type that worked really well, like the Nippon Denso U-groves. The U-grove plugs are still the best for my ancient 1978 Yamaha XS-650SE motorcycle (which I discovered a ways back are a copper core design). Nothing comes close for solid performance and cold start ease and I didn’t mind swapping them every 10-12k. That was what you did then (and 10k was a lot more than 6k after all). From that experience I switched from my American plugs and have enjoyed using them in all my old machines, even lawn mowers, for decades.

    My modern cars have all OEM specced for Platinum and Iridium’s. The Iridium’s are definitely better of the two, but vs old-school copper… don’t know. Never tried them in new cars. I now discover they might be a better choice for us old wrenchers who care about every mile being “righteous” and love to get our hands dirty blacksmithing our rides. My modern rides will give them a trial vs their OEM spec. Maybe get back to you if I can remember to. ;^D

    Reply

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