know your engine bay: engine blocks explained

The engine block is a crucial component of your car’s power system. It is the main structure of the engine, and acts as a foundation upon which all the engine’s moving parts are built, including the cylinders, driveshaft, and more.

To average car owners, the engine block can seem overwhelming. With so many moving parts and intricate details, you’d be forgiven for not wanting to venture inside over fear of causing damage.

However, understanding what goes into the engine block is essential knowledge for any car owner, as doing so gives greater knowledge upon common points of failure, helping you get out on the road that bit quicker.

In this piece, we’ll delve into the various parts of engine blocks, explaining how each piece works in tandem to keep you moving forward.

what is an engine block?

An engine block is the base of the internal combustion engine (ICE). It contains a cylinder block and a crankcase, and comes in either one or two parts. Engine blocks are constructed with numerous materials, with the most common being metal alloys, but there can be traces of rubber for any gaskets needed to ensure a smooth, continuous engine block function.

engine block parts

Engine blocks typically include the following components. For a more specific look at the one in your car, you may wish to review the manual for and hunt out the engine block diagram.

• Cylinder bore: These are the hollow spaces in the engine block that contain the pistons and combustion chambers.
• Pistons: These are the cylindrical pieces that move up and down in the cylinders, creating pressure and suction.
• Crankshaft: This is the main shaft that connects the pistons to the wheels of the car.
• Bearings: These are the components that support the crankshaft and reduce friction.
• Main bearings: These are the bearings that support the crankshaft in the main journals.
• Camshaft: This is the shaft that opens and closes the valves in the engine.

types of engine blocks

There are three types of engine blocks that are most common within modern cars: inline, V, and flat.

inline engine block 

Inline engine blocks are most commonly found in smaller cars thanks to their reduced footprint and simplicity. They have cylinders arranged in a single line, making them more efficient with fuel use and often smoother in operation. One of the main drawbacks of inline engine blocks, however, is their lower performance compared with V and flat engine blocks.

v engine block 

As a slightly more intricate piece of machinery, V engine blocks build on the foundations of the inline engine block by adding an additional line of cylinders. These lines are presented in a V-shape to maximise space, and are the influence behind the name of the block. Such a design allows for the engine block to be made even smaller, while continuing to provide room for more cylinders.

Such engine blocks are therefore found more commonly on high performance, mid-range cars thanks to their ability to produce an even greater amount of power.

 Because of their clever design, V engine blocks are inherently more expensive than inline engine blocks, while also being heavier.

flat engine block

The third and final type of engine block is the flat engine block. Flat engine blocks have similarities to inline blocks in the sense that cylinders are arranged in a single location, horizontally. This allows them to have a greater weight distribution and lower centre of gravity.

Because of this, flat engine blocks are of a slightly smaller size than V engine blocks, and for this reason are almost exclusively found in performance vehicles.

common engine block issues 

As much as we hate to admit it, engine blocks are often prone to failure, with a few key issues cropping up every so often:

cracking

One of the most detrimental of problems with engine blocks is that they generate high levels of heat in a concentrate space. Over time, this causes the block to expand and contract, which eventually results in cracks within the metal alloys. These cracks lead to loss of air pressure, and at worst, leaks.

overheating 

One of the main jobs of an engine block is to transfer heat away from the engine itself. If they are unable to do so, heat levels can rise and eventually lead to a loss of performance, and sometimes complete engine failure.

warping

Another issue with heat dissipation revolves around material warpage. Throughout its lifetime, an engine block will endure many different climates, often in a drastic fashion. This continuous change of cold and warm can cause the materials inside to change, sometimes permanently.

With such low room for error in engine blocks, any change in size can be detrimental to operation, ultimately resulting in extremely hard to diagnose issues like reduced compression ratios and speed degradation.

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