This project is a fully functional inline 4-cylinder engine crank mechanism designed for mechanical demonstration and educational purposes.

The model consists of 17 individual 3D printable components, including a two-piece engine block, four pistons, four connecting rods, piston pins, and a crankshaft with an integrated flywheel. Once assembled, the crankshaft rotation drives realistic piston motion, accurately demonstrating the working principle of an internal combustion engine’s crank mechanism.

All parts are modeled in millimeters and optimized for FDM 3D printing. The design includes proper tolerances to ensure smooth mechanical movement after assembly. The model is intended for printers with a minimum build volume of 300 × 300 mm, as the largest component measures 281 × 259.5 × 259.55 mm.

Recommended print settings:

Layer height: 0.2 mm

Infill: 25–30%

Material: PLA or PETG

Supports required for internal overhangs

This model is ideal for:

Engineering students

Mechanical demonstrations

STEM education

Functional print showcases

Mechanical display projects

The design emphasizes mechanical accuracy, structural stability, and functional movement, making it suitable for both educational use and display.