Four Basic Parts Inside an Engine

01
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What's Inside Your Engine

engine parts
The crankshaft, pistons and connecting rods inside an engine. Getty

We talk about regular maintenance all the time, but sometimes it’s hard to understand just why this maintenance schedule is so important to keep. Understanding a little about the major parts inside your engine may help. 

 

02
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What is a Cylinder?

Engine cylinders
The explosions inside these cylinders make your car go. Getty

Cylinder

The cylinder in an engine is just that, a tube. Inside this tube, however, is where all of the magic happens. Everything described below is happening in a tightly sealed tube called the cylinder. Most cars have at least four of them.

03
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The Automotive Piston Explained

pison
This piston is inside your engine. Getty

Piston

A piston, by design is something that goes up and down. But an automotive piston has a much more brutal fate ahead of it. Not only does it go up and down, but it has to survive thousands of explosions every time you use your car or truck. A piston has a top and bottom. The top is generally smooth, sometimes with little indentations in the surface so the piston won’t hit one of the valves. The top end is where the explosions happen. As the piston pushes itself up into the cylinder, the fuel air mixture that is sealed in there gets compressed, then a spark plug makes the whole thing blow up. Rather than looking like a scene from Star Wars, this explosion is contained inside the engine, and serves only to push the piston back down quickly and powerfully. When the piston is pushed down, the connecting rod pushes against part of the crankshaft, and keeps the engine turning. 

04
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Connecting With a Rod

connecting rod engine
This is the rod that connects the piston to the crankshaft. Getty

Connecting Rod

As described in the piston section, the connecting rod is connected to the bottom of the piston. The piston is domed and sealed at the top, but the bottom part of the piston is hollow. Inside this upside down cup is a wrist pin, a thick steel pin that connects the piston to the connecting rod and allows the rod to pivot back and forth slightly while still being firmly attached to the underside of the piston. This is important because as the connecting rods cause the crankshaft to rotate, the point at which they are attached to the crankshaft shift slightly in relation to the center of the piston. This means it needs to wobble back and forth just a bit so that it doesn’t break off the first time you turn the key. The wrist pins are super strong and almost never break. I’ve seen far more destroyed pistons than rods.

05
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Crankshaft, Center of Power

engine crankshaft
The crankshaft in your engine makes it turn strongly. Getty

Crankshaft

The explosion that happens in the cylinder causes the piston to be thrust downward toward the inside of the engine. The connecting rod connects the bottom of the piston to a certain point on the crankshaft, transferring the energy of the combustion (the explosion in the cylinder) from an up and down movement of the piston and connecting rod to a rotational movement in the crankshaft. Every time combustion occurs in a cylinder, the crankshaft is rotated a little more. Each piston has its own connecting rod, and each connecting rod is attached to the crankshaft at a different point. Not only are they spaced out along the long crankshaft, but they are attached at different points in the crankshaft’s rotation, as well. This means that a different part of the crankshaft is always being pushed along in the rotation. When this happens thousands of times a minute, you get a powerful engine capable of moving a car down the road. 

*Remember, if you forget to add oil to your engine or change your oil regularly, you run a high risk of seriously damaging the inside of your engine. All of those parts need constant lubrication!