29/8/21 I've made quite a few changes over the past few months to improve engine performance, reliability and ease of assembly so i thought I'd upload this separately so people can still download my V1 model.

New video:
https://youtu.be/lh28I5185_M

Below is the details of the original

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Bellow can be found easily on https://aliexpress.com

Required:

2x 608 universal skateboard bearings (crankshaft bearings)
https://www.aliexpress.com/item/33051895647.html?spm=a2g0o.productlist.0.0.f668433ezCGFwU&algo_pvid=b2c6d0fd-5d5b-47a6-94b1-f57ca5a26d32&algo_expid=b2c6d0fd-5d5b-47a6-94b1-f57ca5a26d32-3&btsid=a7104a1b-d334-4ad3-8f70-ca2f6ce4ce47&ws_ab_test=searchweb0_0,searchweb201602_6,searchweb201603_53

4x 682ZZ 2x5x2mm bearings (conrod bearings)
https://www.aliexpress.com/item/32862636969.html?spm=a2g0s.9042311.0.0.27424c4dIet80A

1x 2mm thick lengthy steel rod (cut as needed, for piston pin and conrod crank pin)
https://www.aliexpress.com/item/32297671032.html?spm=a2g0s.9042311.0.0.27424c4dIet80A

2x 35mm x1mm OD O-Ring (head seals)
https://www.aliexpress.com/item/32844105437.html?spm=a2g0s.9042311.0.0.27424c4dYMR0Mb

1x 5mm x1mm OD O-Ring (new BB valve seal)
https://www.aliexpress.com/item/32725251085.html?spm=a2g0s.9042311.0.0.27424c4dIet80A

1x 28mm x1mm OD O-Ring (Piston ring)
https://www.aliexpress.com/item/32844105437.html?spm=a2g0s.9042311.0.0.27424c4dI2J7fy

10x M3x20mm bolts (for fusing points)
https://www.aliexpress.com/item/33003801934.html?spm=a2g0s.9042311.0.0.27424c4dIet80A

1x M4x70 or shorter for crank shaft prop mounting (reinforces crankshaft, 70 works best)
https://www.aliexpress.com/item/32966157667.html?spm=a2g0s.9042311.0.0.27424c4dDC3vpk

1x Standard 6mm air soft BB (new valve)

1x Some form of propeller (shaft is just under 8mm in diameter) or spin-able weight to act as a true flywheel

I'll add other requirements if needed as I print and test - I am by no means an expert CAD user so I'm still learning as I go.

Thanks for looking!

Prusa

i3 MK3

No

No

0.2

25%