Make your own table-top model of a four stroke, single cylinder, OHV (over head valve) engine. This model features a functioning crankshaft, piston, camshaft, and a pushrod-rocker valve system. 

Rough Dimensions: 172mm x 122mm and 273mm tall. (6.75” x 4.8” x 10.75”)

Rough Weight: 450g

Don’t know what any of that means? Perfect! This model is a great way for you to visualize the four steps (strokes) of an engine cycle at your own pace: Intake, Compression, Combustion, Exhaust. This basic design, with valves in the cylinder head being controlled via pushrods translating the motion from a camshaft, is commonly referred to as OHV and is widely used in engine design.

This model requires NO SUPPORTS, NO GLUE, and is FULLY 3D PRINTABLE in PLA. You can download the .3mf files, divide into different prints, and print yourself or, use the pre-arranged .stl plate files. Alternatively, if you have a bambu printer, you can use the “Four Stroke Model Bambu.3mf” file to open the project pre-arranged in Bambu Studio.

PLA Basic Print Settings:
Plates 1, 2, 4: (all pieces except the bolts, valves, sparkplug)

“Four Stroke Plates 1,2,4” Project Preset in Bambu Studio

• Layer Height: 0.2mm
• Wall Loops: 2
• Infill Density: 10%
• Infill Pattern: Gyroid

Plate 3: (bolts, valves, sparkplug)

• Layer Height: 0.2mm
• Wall Loops: 1
• Infill Density: 90%
• Infill Pattern: Gyroid

The weaker pieces printed in Plate 3 can also be printed in a stronger filament if you would like to, but this is not required and we have not tested other filaments!

Assembly: follow assembly instructions in this video or watch above! Note: be very careful when tightening down these bolts. Due to the print orientation, they are prone to shearing if tightened down more than their natural stopping point. 

This project was done by Henry Wallace, Jonah Cicatko, Seth Faberman and Samuel Hartless as part of their thesis “Capstone” project for completion in their Mechanical Engineering degrees at the University of Virginia. 

Full Parts List:

1-A: Engine Block Bottom Half

1-B: Engine Block Top Half

2-A: Cylinder

3-A: Cylinder Head

3-B: Spring (Flat) (x2)

4-A: Piston Head

4-B: Connecting Rod

4-C: Wrist Pin

5-A: Camshaft 1

5-B: Camshaft 2

6-A: Crankshaft 1

6-B: Crankshaft 2

6-C: Crankshaft 3

7-A: Rocker Arm (x2)

8-A: Rocker Axle

9-A: Rocker Support 1

9-B: Rocker Support 2

10-A: Valve (x2)

11-A: Pushrod (x2)

12-A: Camshaft Gear

13-A: Crankshaft Gear

14-A: Hand Crank

15-A: Large Bolt (x2)

15-B: Medium Bolt (x5)

15-C: Small Bolt 

16-A: Sparkplug

17-A: I-Joint (x4)

18-A: Shaft Pin (x2)