Design of the Week: Subaru WRX EJ20 Boxer Engine

3D printed Subaru WRX EJ20 Boxer Engine

3D printed Subaru WRX EJ20 Boxer Engine

This week’s selection is the incredible Subaru WRX EJ20 Boxer Engine functional model designed by Eric Harrell of Santa Cruz, California. 

This 3D model includes a large number of moving parts. The design includes multiple rotating parts move, powered by a small electric motor underneath the engine model. 

In this video, we see an completed example of the Subaru WRX EJ20 Boxer Engine, in motion! Belts transfer the power to multiple rotors, and this mechanical energy is transferred throughout the model. 

This model is notable for several reasons. First, the design itself is very comprehensive, and evidently took much time to create. Harley explains: 

Everything was done in SolidWorks using only hand measuring tools. All parts turned intp STL files, scaled, and repaired using NetFabb Basic.
3D printed Subaru WRX EJ20 Boxer Engine

3D printed Subaru WRX EJ20 Boxer Engine

The other notable aspect is that such a model is very challenging to 3D print, as the tolerances required to ensure the parts not only fit together, but enable sufficiently free movement are significant. I suspect 3D printing this model will require several iterations of the moving parts. Some commenters have said they’ve spent enormous numbers of hours to get the print “right”. 

3D printed Subaru WRX EJ20 Boxer Engine

3D printed Subaru WRX EJ20 Boxer Engine

The model is termed “functional”, meaning that the mechanical parts work, not that the engine can actually be used to power a Subaru, obviously. That said, some commenters sought additional realism: 

And then the headgasket started leaking.

And

Does it burn a quart of oil between oil changes? If so, it is better than the one in my wife's car.

3D printing cannot reproduce everything. 

Via Thingiverse

General Fabb

Kerry Stevenson, aka "General Fabb" has been writing Fabbaloo posts since he launched the venture in 2007, with an intention to promote and grow the incredible technology of 3D printing across the world. So far, it seems to be working!

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