Take a look inside a beautifully crafted 3D printed Toyota inline four-cylinder engine! And learn about how engines work while you're at it! What is an inline four cylinder? What are the advantages of an inline engine? Four cylinder engines are great compact engines, which can fit in many engine bays, are easy to work on, and have balanced primary forces. The secondary forces of I4 engines are not balanced, however, reducing the overall size they can get to without the use of balancing shafts. A