4-Stroke engine with working valves

thingiverse

I created this simple engine as a teaching example for how a 4-stroke engine operates. It features functioning pistons, timing gears, and valves, and only requires printed parts to assemble. To build the model, you'll need to print the following components: 1x Crank Case Lower 1x Crank Case Upper 1x Crank Shaft 2x Piston Lower 2x Piston Upper 2x Piston Head Female 2x Piston Head Male 4x Timing Gear 2x Plugs 2x Cylinder Block 2x Cylinder Head 2x Cam Shaft 2x Cam Cover 4x Valve Spring (Print these at the highest resolution possible for your printer) 4x Valve (Print these at the highest resolution possible for your printer) The entire model snaps together, but I found it worth gluing some components to prevent disassembly. For my assembly, I only glued the lower and upper pistons around the crank shaft. To assemble the model: 1. Attach the upper and lower pistons around the two inner lugs of the crank shaft. 2. Join the male and female piston heads together around the top of the piston uppers. 3. Place the crank shaft with attached pistons into the crank case lower, then snap the crank case upper over it to enclose it. Ensure the piston heads fit through the recesses in the crank case upper. 4. Insert the first two timing gears into the recess on the crank case upper. 5. Press-fit the cylinder block into the crank case upper, securing the timing gears with the pistons inside the cylinder blocks. 6. Fit the remaining timing gears into the slots on the side of the cylinder blocks and use plugs to hold them in place. 7. Place the valve springs into the recesses within the cylinder head, then secure them by press-fitting the valves onto the end of the valve springs. 8. Press-fit the cylinder head to the top of the cylinder block. 9. Insert the cam shaft into the cylinder head and secure it using the cam cover.