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Oily Bits: Introduction

In a ten part series, our very own Mechanic will talk us through just what goes on 'under the hood'.


Accelerating hard out of a corner, my rear view mirror suddenly filled with clouds of white smoke.

I accepted that this, most likely, was a bad thing. My car at the time, an old Triumph Dolomite Sprint, seemed to be running alright but clearly all was not well.

Minutes later the needle on the temperature gauge made an alarming bid for freedom, soaring deep into the red zone. Game over.

Swerving the Triumph into the nearest parking space, I killed the engine. The silence was perforated by the angry tick of rapidly cooling metal, and an unsettling hiss from under the bonnet.

With the car back home, I was confronted with the fact that the engine was going to have to be rebuilt. Manuals to hand, and with a few tools and several beers, the work began. A few days later the car was back on the road and fighting fit. Admittedly I had a few rogue bolts left over, but it didn't seem any worse for wear.

My neighbour, curious as to what I had been doing, asked me what had happened. "The head gasket went between cylinders two and three", I replied confidently. A blank look washed over his face.

It then occurred to me that, these days, there's usually not much chance or necessity for people to learn about engines. Even if you've got an appropriate book or web page to refer to, what makes an engine work can still prove baffling.

Look under the bonnet of an old car and it's usually pretty easy to point out the engine and relevant parts. A modern car's engine bay, however, can be a lot more daunting. It's usually crammed full of pipe work, and more often than not the whole thing is obscured by boring sheets of plastic. Although old and new look very different, the basic principles remain the same.

Stripped down to the bare necessities, an engine is something that simply converts chemical energy into mechanical motion. The chemical energy comes from the fuel and the air that the engine feeds on.

The engine needs air because it contains oxygen, which is required for the fuel to burn. This process of combustion generates heat and pressure. The engine utilises this to generate a force that can be used to drive the wheels. The more air and fuel you can get in to an engine, then potentially the greater the power it can generate. That, of course, isn't the whole story.

So, If you've ever wondered how an engine and all its associated components work, you've come to the right place. Maybe you want to find out more about the basic design, or perhaps you'd like to know how turbocharging or nitrous oxide can make an engine more powerful.

We're going to break an engine and its relevant technologies down into manageable chunks, giving you the opportunity to learn everything you need to know.

Let's get started.