A flathead engine, also known as a sidevalve engine is an internal combustion engine with its valves contained within the engine block, instead of in the cylinder head, as in an overhead valve engine.
Printing and Assembly
The parts should be printed on a smooth build plate, not textured.
If possible, avoid elephant foot.
I printed the model on a PRUSA MINI, with PLA+ filament, layer height 0.15 mm.
I use Hard Plastic Glue where necessary.
For assembled and exploded views, use .stl files 00… 01... 02… 03… (do not print).
Printing and assembly in alphabetical order (A1 → J1).
Printing tips are available for many parts.
Dimensions: 89 x 98 x 149 mm.
Weight: 0.14 kg.
Metal parts
To join the cylinder to the crankcase, two metal 70 mm M5 threaded rods are needed, and two M5 nuts .
Two coil springs are needed for the valves, 10 mm width x 15 mm height. Wire thickness 0.6 or 0.7 mm (AliExpress).
Updates
Update 31-5-2023 Maybe you prefer v.2.0 : 4 Stroke Flat Head Engine v2.0 by Bootjevaarder | Download free vc model | Printables.com
Update 7-3-2022: A matching 2 speed gearbox you can find here: Constant Mesh Two Speed Gearbox by Bootjevaarder | Download free STL model | PrusaPrinters
Update 24-2-2022 “G2-Carburetor.stl” is added, as an alternative for “G1-Manifold.stl”.
The author marked this model as their own original creation.