Engine Block : The Automotive Building Blocks Of Power
An engine block also called a cylinder block is the main structure of an engine. It is made to house the engine components that are responsible for turning combustion into mechanical power. It is also the single biggest piece of metal on the entire engine.
Engine blocks used to be made with separate components bolted together, However, in more modern times casting techniques improved to produce a single-piece block called monoblocks. Engine blocks and monoblock are one and the same.
In the making of an engine, the engine block is one of the most important pieces to consider when it comes to materials and design. The engine block is made strong for other parts to be bolted to it. Engine components like the flywheel, cylinder head, and oil sump are all bolted to the engine block, making a more complete engine. In this article, we will explore the key features of an engine block so you can have a better understanding of how your engine works.
What you will learn about :
How many engine blocks are there?
There are three most common engine block designs out there. These three designs are directly connected to the layout of the pistons. We have the popular “V” engine block, the inline engine block, and the flat engine block. Towards the top of the engine block, you have what we call the engine block deck. This is where you can see the engine block bore. The bore is the big wholes you can see where the cylinders are. This signifies how many pistons an engine will have.
The number of engine block decks and design is what separates them from each other. A “V” and a flat engine block have two decks compared to one on an inline engine block. In an inline engine block, the pistons are arranged in a straight line, hence the name. The “V” and flat engine block have 2 decks located in different areas, which is the design that differentiates them. In the “V” block the decks are at a V angle away from each other. Whereas for the flat engine block, the decks are on opposing ends.
Construction of the engine block
When constructing an engine block the strength and weight of the materials used play a big role in the performance of the engine. There are two materials that engine blocks are generally made from. These materials are Cast Iron and aluminum. Cast iron blocks are the strongest of the two and have been used mainly since the beginning of engines. This material has great resistance to wear and damage. However, a cast iron engine block is heavier than an aluminum engine block. Casting is the main method of making these engine blocks. In the modern era, casting techniques have become so advanced that the strength of an aluminum block can be much more relied on because of how it is made.
Cylinder and cylinder liners
The cylinders of an engine block are the big holes you can see from the engine block deck where the pistons and connecting rods are housed. This is usually referred to as the bore. In cast iron engine blocks these cylinders are one piece all molten together in the process of casting. In an aluminum engine block, there are cutouts for these cylinders where cylinder liners are placed to then house the pistons and connecting rods. These cylinder liners are usually made from cast iron because of their superior strength and properties when it comes to processing the combustion in an engine. An aluminum engine block usually has added cast iron parts such as the cylinder liners and main bearing caps for added strength.
What are the 5 components of the engine block?
In the construction of an engine block, there are five components to take into consideration for engine performance. These components are :
- Cylinders
- Cylinder head
- Oil Galleries / Pathways
- Coolant Passages
- Crankcase
These five components play a large role in the outcome of your engine. Oil galleries and coolant passages are the small wholes in an engine block that are strategically placed in certain areas for maximum cooling and efficiency of the engine. Oil galleries spread from the oil sump through the crankcase all the way to the top of the cylinder head. There are three different engine block deck designs that exist for different ways of cooling the cylinder depending on the application. These three deck designs are called Open, Semi-open, and closed. These three deck designs are variations in the size and space of the coolant passages around the cylinders. Less or more space and bigger smaller wholes will allow for less or more cooling of the cylinder while offering less or more structural support.
How does an engine block go bad?
An engine block is made from very strong materials such as cast iron and aluminum alloys. Engine blocks are one of the strongest components of an engine because they house the components necessary for the process of combustion. So what makes an engine block bad is if it cannot properly facilitate that function. That being said, there are a couple of things that can compromise an engine block. One of which is in the casting process. Modern Casting techniques are very advanced however, if an engine block is poorly cast this can open up the block to being compromised. This means that the materials of the engine block can get warped due to heat or cracked or damaged in some way.
Another way that an engine block goes bad is engine knock and pre-ignition. Engine combustion is a very controlled process, and if combustion happens out of control, it is called an engine knock and pre-ignition. Engine knock and pre-ignition happen when the cylinders are poorly cooled. If a cylinder gets too hot the air-fuel mixture can ignite in different areas of the cylinder, rather than the flame front of the combustion spreading evenly after the sparkplug fires. Pre-ignition happens before the sparkplug fires and can have more damaging effects. This only adds to the already high temperatures, which can cause the engine block to warp or become cracked or damaged.
How do I know if my engine block is bad?
Engine blocks are designed to house the components that process combustion to mechanical power. This process generates quite a bit of heat. When an engine block is designed, it is designed with proper cooling and lubrication of these parts in mind. That being said engine blocks are designed with coolant passages and oil pathways separate from each other. An engine block is also properly sealed and it does a very good job at containing the combustion process. So when an engine block is bad we will begin to see a few symptoms related to a poor performance in cooling, lubrication, and a lack of sealed combustion.
Symptoms of bad engine block are:
- A mixture of coolant and engine oil leaking (may also be a symptom of a blown head gasket)
- A blu-ish smoke coming from the engine (The combustion process isn’t sealed off)
- Upon visual inspection of the engine block, you can see visible cracks in the block (Not as easy as it sounds, you may require a professional)
- Reduced engine performance/acceleration
- Low engine compression (The combustion process isn’t sealed off)
- A dramatic drop in coolant levels
- A dramatic drop in oil levels
- Cross-contamination of oil and antifreeze (most common symptom)
- Engine overheating
Conclusion
Engine Blocks are quite literally the building blocks of automotive power. With a better understanding of the purpose it served you can now have a better understanding of the full operation of your engine itself.
FAQ’s
What is the strongest engine block?
Stronger engine blocks are typically made from cast iron. Cast iron is more resistant to wear and heat.
What metal are most engines made out of today?
75% + of combustion engines today are made from aluminum alloys and the rest are made from grey cast iron.
What material is best for an engine block?
The best materials depend on the application. Cast iron’s main benefit is its strength. Cast iron has properties that allow you to make more boost/power for cheap while aluminum alloys allow for better efficiency because it is lighter. In playing around with a sports car cast iron blocks have the benefit of being stronger for more power. In a basic commuter car, you can derive more fuel efficiency from an aluminum alloy engine block because the parts are light and thus easier to move.
