The term is thrown around often, but what actually constitutes Subaru's "boxer" engine? With the insightful mind of Jason Fenske and a 3-D printed model of a 4-cylinder boxer engine, we're all in for some learning.
In this video, Jason, host of Engineering Explained, walks viewers through the unique design of a Subaru boxer engine and how it operates. There are flat engines, but Subaru's boxer engine is different altogether. The pistons themselves lay flat—like other flat engines—but what makes Subaru's design distinct is the fact the pistons move in and out together. That means there are different crank pins for each piston. The term "boxer" engine is sometimes referenced due to the fact the pistons mimic boxing gloves punching at the intake and exhaust valves.
The pistons' firing order of 1, 3, 2, 4 means the left side fires before the right in a wonderful synchronicity as the connecting rods work to send the power through the crankshaft, and ultimately, through the transmission.
Eric Harrell created the 3-D model that Jason uses in the video and you can find links to Eric's Thingiverse files to print out a boxer engine of your own on Jason's YouTube channel.
It is cool to see how such a unique engine operates. There's a lot going on while we simply work an accelerator and shift a transmission. See what makes a boxer engine tick for yourself in the video above.