2-Stroke vs. 4-Stroke Engine: What’s The Difference?

There is a lot of information out there on your car engine because there is so much that goes into making that engine run. One thing we haven’t touched on yet is the difference between a 2-stroke and 4-stroke engine. Familiar with the term? That’s ok if not! We’ll explain it below so you can impress your mechanic next time you talk cars 😉

2-Stroke vs. 4-Stroke Engine: What’s The Difference?

In our article called Car Basics 101: How Your Engine Works we talked about a lot of specific terms that go into making an engine run. Including, using the term ‘4-stroke’ but not really going into detail on what that really means. The word “stroke” in the car industry refers to the movement of pistons. A 2-stroke engine is not going to be as popular anymore compared to a 4-stroke engine for numerous reasons. Some older cars are still 2-stroke, as well as other small motorized vehicles. The main reason is that people believe 2-stroke engines are worse for the environment but we’ll get into that below!

2-Stroke Engines

2-stroke engines complete one power cycle moving up and down, in ‘two strokes’ of the piston to one crankshaft revolution. This type of engine will have one compression stroke followed by the explosion of the compressed fuel; on the return stroke, exhaust is let out and new fuel mixture enters the cylinder. These engines require oil to be pre-mixed in with the fuel, which is why some believe they are worse for the environment because this oil mix gets pushed out into the air when your engine is running. Ever see blue smoke coming out when a car/motorcycle accelerates? That’s the two-stroke coming into play!

4-Stroke Engines

Opposite to a 2-stroke, 4-stroke engines complete two-strokes during each revolution, instead of one. Then this is followed by 2 return strokes which equal the ‘4-stroke’ term. These engines don’t require an oil-fuel mixture so can run off regular gasoline. Because of this, fuel isn’t consumed as quickly since it’s once every 4 strokes instead of 2 strokes. These engines are quieter then 2-stroke engines & last longer since they run on lower RPMs.

While you don’t see a lot of 2-stroke cars out there, they definitely exist! It’s more common in power scooters & motorcycles. It’s not a complicated term but definitely one you should know. Basically, two-stroke engines use an oil/fuel mixture to move the pistons up and down during one crankshaft revolution. Four-stroke engines run off gasoline and have two strokes to one crankshaft revolution.

Explain that to your friends & I know they’ll be impressed! Until next time 🙂 #motorwithconfidence

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Comments 1

  1. This difference is not easy to understand. Very successful post, thank you.

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