Spark plug maintenance is difficult. Even more difficult is to choose the best type of spark plug. Before choosing the suitable type, let’s understand its types first.
So, what are the types of spark plugs?
There are mainly 3 types of spark plugs:
- Copper spark plugs
- Platinum spark plugs (single and double)
- Iridium spark plugs
Let’s now discuss each of these spark plug types one by one.
#1: Copper Spark Plugs
Copper is the first spark plug material used in automobile engines. It was the most extensively used spark plug material by the manufacturers – up until the last decade. Even today, you would find copper spark plugs fitted in many engines worldwide.
Helpful read: spark plug history
The reason why copper spark plugs were so popular boils down to two main reasons. First, copper is cheap. Second, copper is an easily available material for manufacturers.
The low cost and ease of sourcing made copper a go-to material for the spark plugs among the available options that could conduct heat and electricity.
However, there are downsides as well. Copper has a melting temperature of 1085 celsius. While this is a reasonably high melting point, you would want your spark plug to be even higher since it has to withstand high engine temperatures.
In addition, copper oxidizes fast to form a rust layer. This is not at all desirable in a spark plug. To overcome this hurdle, Nickel is usually added to form an alloy. Other metal pieces are also used in the spark plug to overcome this low melting temperature. They are used to distribute the heat.
The resulting copper and nickel alloy is more rust-proof. But on the flip side, the material becomes softer and wears out fast.
Another downside of copper spark plugs is they do not last long. Copper spark plugs need to be replaced every 30,000 miles of distance traveled.
Advantages
- low cost and economic spark plugs
- Easy to source
Disadvantages
- Comparatively lower melting temperature
- Wears out fast
- Has a short life span and needs to be replaced early
#2: Platinum Spark Plugs
Platinum spark plugs are the next spark plug material that is widely used. On an interesting note, platinum spark plugs provide the same if not slightly inferior performance when compared to copper spark plugs.
However, what they excel is in their longevity. Platinum spark plugs last longer than copper ones. Almost 2X times.
Platinum spark plugs need to be replaced every 50,000 to 60,000 miles of distance traveled.
Platinum spark plugs also have better melting temperatures and hence, can operate at a higher temperature. A typical melting temperature of platinum is 1768 celsius.
Another better aspect of platinum spark plugs is they do not allow carbon deposits. The platinum coating on the electrodes prevents too much carbon deposit formation. This was a huge problem in copper spark plugs.
Carbon deposits on the electrodes would eventually make the spark plugs dysfunctional. No more electric spraks. Eventually, they need to be replaced.
Advantages
- Has a good life span
- Does not allow carbon deposit formation easily
Disadvantages
- Slightly poor performance than copper spark plugs
- Costs higher than copper plugs
Single and Double Platinum spark plug
Simply put, a single platinum spark plug is your usual spark plug. There will be spark ignition only once per 4-stroke cycle. The spark plug ignites during the compression stroke only.
Double platinum spark plugs, on the other hand, will ignite the fuel twice in a combustion cycle. Once in the compression stroke and another one in the exhaust stroke as well. This is to ensure to combust any unburnt fuel in the engine even after the combustion cycle has taken place.
Put simply, the difference between a single and a double platinum spark plug is how many times the spark plug sparks in a combustion cycle. Once for the single platinum spark plug. Twice for the double platinum spark plug.
However, not many use double platinum spark plugs. Rarely do you find a double platinum spark plug fitted inside your vehicle engine. If you want to know more, here is a detailed post on double platinum spark plugs.
#3: Iridium Spark Plugs
Iridium spark plugs are the best spark plugs in terms of performance. They perform better, have a higher life span, and can withstand far higher temperatures than the other two.
The melting temperature of Iridium is 2446 celsius. This is far higher than that of both copper and platinum. As a result, iridium spark plugs can operate under far high temperatures in the engine combustion chamber.
Iridium spark plug also requires less current to create the spark and ignite the fuel in the combustion chamber. Clearly making it the best spark plug in the market.
You can definitely notice the improved performance whenever you shift from copper spark plug to iridium spark plug. The acceleration will be quick, smooth, and faster.
The icing on the cake, iridium spark plugs have a high life span too. You need to change the spark plug for every 100,000 miles. Far higher than copper and iridium spark plugs.
The downside of all these amazing qualities is iridium spark plugs are costly. Typically, iridium spark plugs 4X of copper spark plugs. I will say the extra cost is worth it. But again the tradeoff still depends on you.
Advantages
- High performance
- Great lifespan
- Can withstand high temperatures
Disadvantages
- The costliest spark plug on the market
Copper vs Platinum vs Iridium Spark Plugs
Now that we know about each of these spark plugs, let’s compare them on specific parameters:
Power and Performance
Iridium spark plugs are the best in terms of performance. The power generated in the engine is at its optimum with iridium spark plugs compared to the other two.
Surprisingly, between copper and platinum, copper spark plugs provide better performance than platinum spark plugs. Platinum spark plugs, despite being considered superior to copper spark plugs fall short in performance.
Lifespan
Iridium spark plugs have the best lifespan, followed by platinum spark plugs. Copper spark plugs have the lowest life span and need frequent replacement.
| Spark Plug Type | Approximate Lifespan |
|---|---|
| Copper | 30,000 miles |
| Platinum | 50,000 miles |
| Iridium | 100,000 miles |
Operating Temperature
Again, the iridium spark plug is the most well equipped to handle high operating temperatures in the engine.
Between platinum and copper, platinum spark plugs fare well and withstanding higher temperatures whereas copper spark plugs cannot withstand high temperatures. Copper has a low melting point. Usually, nickel is added to copper to increase its heat resistance and decrease rust formation.
Deposit Formation And Wear
Both platinum and iridium do not allow carbon deposit formation easily. But, the same cannot be said about copper spark plugs.
Even wear resistance. Both platinum and iridium spark plugs have good wear resistance. Copper spark plugs, on the other hand, wear out at a much faster rate.
Cost
With great performance comes great cost. It must not be surprising that iridium spark plugs are the costliest ones. Followed by platinum spark plugs.
Copper spark plugs are the cheapest type of spark plugs out there. Copper is easy to source. Manufacturers can get it readily available. Hence, the low cost for copper spark plugs.
Which type of spark plug is best?
Iridium spark plugs are the best type of spark plugs. They deliver superior performance and have a higher life span.
However, iridium spark plugs are costly. Not many are eager to go for them.
That brings us to the point. Always check for the spark plugs recommended in the owner’s manual. If your vehicle is recommended to have iridium spark plugs, you just can’t downgrade to a copper or a platinum spark plug.
On the other hand, if the manual recommends a copper spark plug, it probably is best to go for copper spark plugs rather than upgrading to a platinum or an iridium one.
