What’s Better Cast Iron or Aluminum Cylinder Heads?

by Chris Lewis.

Choosing the right cylinder head is a vital and hard choice. It could either make or break your engine’s performance. The cylinder head is responsible for holding the valves and forming the combustion chambers. And it controls the engine’s power and how it operates.

The most common types of cylinder heads that are used by many are the cast iron and aluminum cylinder heads. But what’s better, cast iron or aluminum cylinder heads?

Well, this article is here to answer all your questions. You will be able to get to know the advantages and disadvantages of both these cylinder heads so that you can make the best choice for your vehicle’s engine.

Cast Iron Cylinder Heads

Cast Iron Cylinder Heads
Cast Iron Cylinder Heads

Several car owners use this cylinder head because it offers several advantages for your engine like durability and reliability, but it has some drawbacks too. All the advantages that it offers make it a worthy choice for your engine.

Cast iron is a very versatile and most of all, durable material. It can last long against the wear and tear that comes with use. Not only that, but when it incurs cracks and cuts, it can be welded, drilled, or pinned to fix it up.

You’ll be able to save a lot more money in the long run because you won’t need replacements too frequently.

Street engines will benefit from a cylinder head made of cast iron because it will conduct heat fast and help the engine reach operating temperature.

Starting your engine will be much faster, even when it’s from a cold start. Your engine will also be able to have higher thermal efficiency because it can keep heat easily. And it keeps a stable structure even when it is subjected to great heat; it won’t expand.

In terms of affordability, this would be a brilliant choice. Cast iron is more affordable when you compare it to aluminum-made cylinder heads. This way, you won’t have to break the bank to give your engine an upgrade.

The only issue when choosing this type of cylinder is that it has a considerably heavier weight.

If you often go racing the weight of the engine is an important factor to consider. A lighter engine will be less likely to slow you down. But if you’re not into racing that much, its weight won’t be much of a deal-breaker.

Overall, this will improve your car’s durability, efficiency, and performance. There’s no wonder why so many car owners choose this.


  • Has good thermal efficiency
  • Affordable
  • Heats up fast
  • Very durable
  • Doesn’t expand with heat


  • Heavy

Aluminum Cylinder Heads

Aluminum Cylinder Heads
Aluminum Cylinder Heads

Aluminum heads have become quite popular nowadays because they also have a set of great characteristics that make them great for all sorts of engines. Racing cars will also find it more ideal compared to the ones made of cast iron.

Since aluminum is a very flexible and soft material, machining it and making repairs on it is much easier. If there are cracks or other damages, it can be simply welded to get it back to top condition.

Aluminum is also a lightweight material, so it is an ideal choice for racers. This significant weight reduction enhances overall engine performance and doesn’t slow down your car with any unnecessary load.

Another great thing with cylinder heads made of aluminum is that they conduct heat a lot easier and quicker.

When you compare it with an iron head, it will be able to heat up at a rate that’s 3 times faster. This will make way for faster and more reliable engine startups even when it’s a cold start.

It also reduces the risk of detonation or pre-ignition that can damage the engine by diverting heat away from the combustion chamber when it is accelerating at fast rates.

The downside to this is that it can reduce the thermal efficiency of the engine because it lets heat escape through the head of the cylinder. And aluminum heads also have a more expensive price range. Compared to cast iron heads, they cost a few more dollars.

Considering its advantages and disadvantages, an aluminum head will still make a good choice for your car. And its slightly higher price can be justified by its performance. It’s become a famous choice for a reason.


  • It is very lightweight
  • Heats up at a faster rate
  • Very easy to weld and repair
  • Reduces pre-ignition and detonation risks
  • Great performance


  • Slightly more expensive
  • Lower thermal efficiency

Difference Between Cast Iron and Aluminum Cylinder Heads

Difference Between Cast Iron and Aluminum Cylinder Heads
Difference Between Cast Iron and Aluminum Cylinder Heads

Choosing between Cast Iron and Aluminum heads is not easy. Depending on your preferences or the model of your vehicle, one of them could be more ideal.

But they do have distinct characteristics that can help you in deciding which one will suit your engine better. Both these are great choices, but they also have disadvantages that you should consider.

In this part of the article, you’ll be able to have a better view of the several differences that these two cylinder heads have. You’ll be sure to decide the best one for your car.

Durable Build

A durable cylinder head is always a better choice because it will be able to last longer, therefore, saving you from untimely replacement costs.

Both aluminum and cast iron heads can last wear and tear, but cast iron will be the more durable choice.

Aluminum is a very soft material, while cast iron is sturdy and can handle even excessive forces. Cast iron heads can also resist structural changes that are brought about by high temperatures.


Aluminum has more of an advantage when it comes to weight. You can reduce weight by up to 50 lbs. when you opt for an aluminum cylinder head than a cast iron head.

Although for a streetcar, a lighter cylinder won’t make much of a difference, but if you have a race car, weight is always an important factor so you can drive at much faster speeds.

Ease of Repair

Cylinder heads can tend to incur dents and scratches over time, and repairing them can be easy, depending on the type of cylinder you’re using. In general, aluminum heads will be easier to repair compared to iron cast cylinder heads.

This is mainly because aluminum is a softer and more flexible material making it easier to weld.

Heating Efficiency

Between the two, aluminum heats much faster compared to iron cast heads. It can heat up at a rate that’s thrice as fast.

This will make starting up your engine much easier and in a lesser amount of time. The great thing about aluminum is that it can also reduce risks of detonation and pre-ignition.

Iron cast cylinder heads, on the other hand, have a higher thermal efficiency even though it has a slower heating rate. This is because it can retain heat much longer.


Cast Iron is a used material in several industries because it is easy to produce, and its wide availability makes it a much cheaper option.

Final Words

Hopefully, we helped you determine what’s better: cast iron or aluminum cylinder heads. Just take note that if you have a street engine, an iron cast cylinder head will work fine.

But if you’re willing to spend a few more dollars and don’t want the extra load for your car, aluminum heads will make a great choice.

About Chris Lewis.

Chris Lewis is a passionate individual with a deep affinity for the world of automobiles. From a tender age, his fascination with cars was nurtured by his father, a seasoned mechanic based in the vibrant city of San Francisco. Growing up under the watchful guidance of his skilled father, Chris developed an early aptitude for all things automotive.

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