How Engines Work - (See Through Engine in Slow Motion) - Smarter Every Day 166
Hey, it's me Destin. Welcome back to Smarter Every Day. You've probably cranked a car engine thousands of times in your life, right? You're familiar with that roar as the engine comes to life? Have you ever thought about what's going on inside the engine? Think about it. You've got thousands of explosions happening every minute, and they all come together to make one unified sound.
Well, today on Smarter Every Day, I wanted to learn what's going on in an individual cylinder. We kind of get a feel for how an explosion propagates inside of a combustion chamber with the transparent potato gun video, but for years, I've wanted to see inside of a working engine. Today on Smarter Every Day, we're going to get to see this.
Someone posted on the Smarter Every Day subreddit that there's a channel called 805roadking that has created just this: a transparent engine. So I loaded up the high-speed camera and went to Cinnaminson, New Jersey, to meet Everett. This looks like the right place.
(Destin): You Everett?
(Everett): Destin! Hey, what's up?
(D): How's it going?
(E): C'mon in.
(E): We were just getting your phone because my phones are out.
(D): Hey, what's up? I'm Destin, nice to meet you.
(D): How's it going?
(E): Pretty good.
(D): It's a pleasure to meet you guys. Oh dude, you have a jukebox!
(E): You like it? A 1953.
(D): That's awesome! That's awesome!
(E): I'll let you take a picture of it later.
(D): (Laughing) How are you guys doing? Is this the shop?
(E): This is it, man.
(D): Oh, it smells like freedom!
(Destin, voiceover): This is Everett. He works with his buddy Mike to create all kinds of little mechanical marvels. Their specialty is taking apart a single-cylinder Briggs & Stratton engine from the 50s and converting them into all different types of things. For example, this one is turned into a hit and miss engine, which is really hard to do. This one is an absolute Frankenstein. They took four single-cylinder engines, chopped them up, and put them together to make one four-cylinder engine that runs like a kitten. It's amazing!
(Mike): The seam is actually right here.
(D): And you welded that!?
(M): Yeah.
(D): How did you weld four engines together and then have it aligned so a crankshaft could go in there?
(M): It took a long time to do.
(D): If you don't really appreciate what I'm saying here, just understand these guys are doing very difficult things with very crude tools. They're basically performing mechanical magic. Which is why I wanted to see...this.
(D): This is it, huh? I love it.
(Voiceover): On a normal Briggs and Stratton engine, the spark plug is right in the middle on the top of the cylinder and is fired by a magnet that moves past a coil. These guys moved the spark plug so you can see down into the engine and came up with a clever way to fire it with a buzz coil from the 1920s. They're also running the cylinder on propane instead of gasoline because it's cleaner and it makes the engine last longer. Now that we understand that this is basically a normal engine that they've taken the metal head off of and replaced it with an acrylic head, it's time to get the high-speed camera set up and see the one thing I've been wanting to see for several years - an explosion inside the engine.
(D): I can't tell you how excited I am about this camera mount you built (laughing) with its engine hoist. It's like, it's the most acoustically pleasing thing I've seen in a while.
(M): I just triggered it.
(engine roaring in slow motion) (long roar followed by short sparks and more roaring)
(D, voiceover): Okay, this is pretty and all, but I want to understand exactly what's happening. We have the piston on the left, moving up and down inside the cylinder, and two valves on the right. Let's take a look at how a 4-Stroke Engine works and count off each of the four strokes along with me. The first thing that happens is one of the valves on the right opens, allowing a fuel-air mixture to be drawn into the cylinder. This stroke is called the intake. When the piston gets near the bottom of the cylinder, the intake valve closes, and then the piston starts to compress the gas. This is called the compression stroke.
The third stroke is the pretty one. This is called the power stroke. The explosion happens and increases the pressure inside the cylinder, which applies force to the face of the piston, pushing it down. When all those gases have burned after that third stroke, the exhaust valve then opens and the fourth stroke, called the exhaust stroke, clears the cylinder of all those exhaust gases. The intake valve then opens back up, and the process starts over and over again.
Timing is everything in an engine to make sure it works properly. For example, you want to make sure the spark happens just before the piston is at top dead center because you want the pressure to be building up at the same time as that piston is ready to start moving back down. When you hear a person talk about the advancing or retarding of the timing of an engine, that spark timing is what they're talking about. If you look really closely, you can see this part happens just before the piston reaches the top of the stroke.
I asked Everett and Mike if they would dare to run the engine on gasoline for me because I wanted to see a brighter flame. I was really excited when they said yes. And I was even more impressed when they said that they could change that engine over in just a matter of seconds.
(D): so we're already converted, like, you're done?
(M): that's it.
(D): that was fast.
(Slow motion engine. Burst of sound every time it lights up)
(Regular speed engine sounds)
(D): man, that's good right there.
(Loud, rapid bursts)
(Electric spark sounds)
(Slow motion flame roar sound)
(D, voiceover): Ok, now that you know how an engine works, watch each of the four strokes and see if you can identify each one. Intake, compression (sparks sound), power, exhaust. Intake, compression, power, exhaust.
Now think about the engine in your car; all the explosions are synchronized together to make that one constant engine roaring sound. I think what I found really refreshing about making this video is you've got Everett who is retired, and you've got Mike and Bill who later came in the shop and helped us out. These guys are totally different generations, but they're all working together because they absolutely love engines in, like, a completely unapologetic way. It's beautiful.
Anyway, I'll leave links in the video description to all of their YouTube channels, and I would enjoy it if you would consider subscribing. They're small channels; that kind of thing would really help them out.
(D): Big thanks to 805roadking for helping me visualize an engine, so thank you very much Bill, Everett, Mike, it was a blast.
(Everett): This is dirtbike5100 and SmallEngineMechanic.
(D): oh yeah, there you go, these guys all have youtube channels I'll leave links in the video description.
I hope you enjoyed this episode of Smarter Every Day. It was sponsored by Audible, and the book I'm about to recommend means a great deal to me. You know, Everett and Mike, they have this, you know relationship, even though their ages are quite different. My dad recommended that I read this book a long time ago, and it was fantastic. It's about a young man trying to figure out his way in the world in 12th century Europe after his dad is taken. We'll just say that. I don't want to give anything away, but it's called
(Audiobook narrator): The Walking Drum by Louis L'Amour.
(D): That is John Curless, and he does a dang good job reading this book. I enjoyed it. It's a thick book, so I can't really sit down and read this like I used to be able to, but with audiobooks, I can listen to it back and forth on my drive. I've even listened to it while like bush hogging the field. I really enjoyed this book; it's full of fantastic quotes that is just wisdom. I really enjoy it, so please get this book at audible.com/slash/smarter.
(Cut) Psst, there's a behind-the-scenes video on the second channel that goes into the timing of that engine, how they adjusted to have a shape, the acrylic, all that cool stuff (whispers) go check it out.
Did we just figure out how to..
(E): I think we fixed it.
(D): ... fix it with back pressure? We fixed it with back pressure?
(M): Look at that!
(D): Oh! Look at that!
(Indistinct speech) It just needed back pressure?