1. Air intake filter
   Spark plug
2. Throttle body
   Blinker fluid

The spark plug puts the spark right in the cylinders, igniting the air and fuel mixture. Without spark plugs, your engine wouldn't produce any power, and your car would just sit.

1. Fuel injector
   Gas cap
2. Piston
   Radiator fan

Your fuel injectors are what deliver the gas to the cylinders, making them the final component in a chain of parts, at least in a direct injection setup. More modern engines use such a setup, because it boosts efficiency and power.

1. Fuel rail
   Valve cover
2. Valve springs
   Air intake

All cars have an air intake, although some have unique designs and placements. Without one, you won't get the oxygen necessary to combust fuel. Going with an air intake that speeds up the flow can impact performance for the better, especially when combined with other modifications.

1. Camshaft
   Spark plug
2. Gasket
   Gaffer

As the camshafts spin, the lobes control when and how much the intake and exhaust valves move. Many tuners will install performance camshafts with more aggressive lobes as a somewhat easy way to get more power from their current engine setup.

1. Hose
   Cylinder
2. Gasket
   Fuel injector

Your engine needs a tight seal to run correctly, and gaskets close up gaps between metallic parts since they're soft. Blowing a head gasket can create all kinds of problems with your car, and should be fixed before too long or you risk even bigger issues.

1. Piston
   Crankshaft
2. Blinker fluid chamber
   Cylinder block

As the main part of the engine, the cylinder block is kind of like the body that houses all sorts of components. It also contains the cylinders, or the chambers were combustion takes place, as well as the water jacket for cooling, and the crankshaft.

1. Piston
   Blinker regulator
2. Rotational limiter
   Spark plug

The piston moves up and down in each cylinder, putting pressure on the air and fuel so it's ready for the spark that ignites everything. After combustion, the piston travels downward again, getting ready to move up and compress the next batch of air and fuel.

1. Connecting rod
   Cylinder head
2. Exhaust manifold
   Camshaft

Engines with an inline cylinder configuration have only one cylinder head, but a V formation means the engine has two, one for each cylinder bank. The flow of air, fuel, and exhaust gases in and out of the cylinders is controlled through the cylinder head.

1. Connecting rod
   Camshaft
2. Speed regulator
   Fuse box

While the crankshaft determines how the pistons move, it's the connecting rod that ties the two together. For that reason, the opening on the bottom is larger, to accommodate the crankshaft, while the top opening is smaller. These must be incredibly durable, otherwise you're facing a big repair.

1. Piston
   Crankshaft
2. Brake pad
   Blinker relay

Ultimately, the part of the engine that sends all twisting motion to the flywheel, and in turn the transmission, is the crankshaft. This part isn't one smooth shaft, but instead is divided into sections, corresponding to the motion of the pistons themselves.

1. Oil cap
   Oil filter
2. Oil sump
   Fuel rail

All oil from the engine ends up in the sump at one point or another. It acts as the collector for the majority of the oil when the engine is shut off, since it sits at the bottom of the engine block, where gravity naturally pulls the oil.

1. Valve
   Blinker fluid container
2. Water jacket
   Spark plug

While the camshaft controls the valves, the valves control the flow of gas, air, and exhaust into and out of the cylinders. When closed, the valves create an air-tight seal nothing can get around.

1. Camshaft
   Valve control valve
2. Blinker fluid regulator
   Push rod

While more common in older engines, the push rod is necessary to control how and when the valves in the cylinder head open and close. Essentially, it creates a connection between the camshaft and valve.

1. Air intake
   Exhaust manifold
2. Water jacket
   Dipstick

Without the exhaust manifold, your engine would spew exhaust fumes all over in the engine bay. In other words, the exhaust manifold is a necessary part for the safe operation of your car, because breathing that stuff is dangerous.

1. Intake manifold
   Exhaust manifold
2. Spark plugs
   Blinker regulator

If your car doesn't have direct fuel injection, the intake manifold is where the special mixture of air and fuel happens, before it flows into the cylinders through the intake valves. The object is to get the ideal mix of air and fuel.

1. Head gasket
   Bottom gasket
2. Fuel pump
   Piston ring

Not only do piston rings seal the air and fuel mixture, plus exhaust gases inside the cylinder, they cut down on friction between the piston and the cylinder wall. The ring must sit inside some grooves that are part of the piston's side.

1. Piston pin
   Connecting rod end
2. Estucheon greaser
   Fluid reservoir beaker

Sometimes called a gudgeon pin, this shaft runs horizontally through the piston. It actually secures the connection between the piston and connecting rod

1. Turbine
   Exhaust manifold
2. Rotor
   Spark Plug

While some things are similar in a rotary engine, the rotor is one of those that's different. On each face of the rotor is a pocket, which accommodates the air and fuel mixture inside the engine combustion chamber. The rotor spins around, using each of its faces to aid in the combustion process.

1. Output shaft
   Spark plug
2. Intake manifold
   Fuel injector

As the rotor moves around in the housing or combustion chamber, the movement puts torque on the output shaft, so it spins too. This creates a smooth, continuous motion, and in turn the even power delivery that makes rotary engines so legendary.

1. Spark plug
   Firefly
2. Fuel injector
   Glow plug

Without glow plugs, you might not be able to start a diesel engine, especially when it's cold outside. Not only do they warm up the diesel, this component can also positively impact engine performance well after, making it a critical part.

1. Spark plug
   Blinker fluid regulator
2. Valve cover
   Breather

Some engines require regular or semi-regular valve adjustments. To make the job easier for mechanics, and to keep the cost of valve adjustments down, engineers design the engine with valve covers. These come off pretty easily, giving you immediate access to all the valves underneath.

1. Fuel pump
   Oil filter
2. Spark plug
   Air intake

The oil in your engine picks up all kinds of stuff, including metal shavings, deposits, and more. Without a filter, the oil wouldn't protect against wear and tear on the engine as well, plus it wouldn't be as effective in helping to cool the engine, making oil filters vital.

1. Jump rope
   Headlight bulb
2. Spark plug
   Ignition wire

Without ignition wires, there's no way to get the electrical current to the spark plugs. To maintain the cylinder compression, these wires have rubber boots that fit over the top of the spark plug wells, which you must ensure are sealed tightly.

1. Spark plug
   Piston
2. Light bulb
   Air filter

The air filter in your car's intake is an essential engine part. It keeps debris from entering the engine, which is why you need to swap it out periodically. Some performance intakes have a cleanable filter, which you may or may not need to oil afterward.

1. Belt
   Spark plug
2. Camshaft
   Crankshaft

Because the belts are usually made of rubber, they don't last forever. Being exposed to the air, plus extreme temperatures under the hood means the belts will start to crack, and may even fray at the edges. Once your belts start to show these signs of wear, you should swap them out immediately.

1. Spark plug
   Oil filter
2. Pulley
   Water jacket

Sometimes, people think the belts on their car are wearing out, when in reality the pulleys are going out. Many experts recommend swapping out the pulleys along with the belts, since you're going to the trouble of taking things apart in that area, and usually pulleys fail not too long after the belts do.

1. Radiator
   Water jacket
2. Spark plug
   Cylinder head

As the coolant flows through the water jacket, it heats up. That coolant then flows through the hoses to the radiator, where it cools off, before being sent back to the engine to do it all over again. Without the water jacket, your engine would overheat and not be nearly as reliable.

1. Engine mount
   Engine intake
2. Spark plug
   Ignition wire

Without engine mounts, your engine wouldn't really be attache to your car, so they're pretty essential. Not only that, different ones have designs that absorb vibrations, so you don't feel the engine running as you're sitting at a stop light, which makes for a more comfortable ride.

1. Carburetor
   Spark plug
2. Oil filter
   Radiator

Basically, a carburetor is like a tube, with the throttle plate to regulate airflow to the engine. in addition, the carburetor also includes a fuel jet, so the two mix together before flowing into the cylinders. This analog design was ditched in favor of fuel injection.

1. Air filter
   Spark plug
2. O2 sensor
   Radiator hose

One of the big advantages with electronic fuel injection is that the system monitors factors such as oxygen density in the air, and adjusts how much fuel goes into the mix. The O2 sensor is key in the process, helping the engine to run more efficiently.

1. Main bearing
   Camshaft
2. Valve
   Radiator hose

The main bearings are what literally make the crankshaft go around, even as the connecting rods push down. They also prevent the forces from the flywheel, clutch, and transmission from making the crankshaft move in any other direction.

1. Oil pump
   Radiator hose
2. Camshaft
   Spark plug

The oil pump does exactly what its name indicates: it pumps the oil throughout the engine. Since the oil sits in the sump at the bottom of the engine, it needs something to create the pressure necessary to get the oil all the way to the camshafts, and do it consistently.

1. Crank sensor
   Valve
2. Cylinder head
   Valve cover

All information from the crank sensor goes to the ECU or engine control unit. It's able to adjust fuel injection, ignition, and air intake for optimal efficiency and power.

1. Air filter
   Spark plug
2. Throttle body
   Exhaust manifold

Modern engines rely on many sensors, including the crank sensor or crankshaft position sensor to run correctly. This means better fuel economy, improved output throughout the RPM range, and greater reliability.

1. Knock sensor
   O2 sensor
2. Camshaft
   Radiator hose

Since detonation is such a violent reaction, the knock sensor only needs to measure vibrations to tell when any spark knock happens. Even though in many cars this sensor is in the lower portion of the block, some have knock sensors in the intake manifold or the upper portion of the cylinders.