Poppet Valve Single

The idea was to make a single cylinder 4-stroke and to make it simple with a poppet valve. Not sure my terminology is correct here, what I mean is an actuated exhaust valve and an intake valve that opens under depression in the cylinder.

  • Connecting Rod – a lightweight aluminium conrod.
  • Crank – challenging with the timing gear machined as one part
  • Crankcase – this has been a joy to machine….until I had a major glitch and I melted the crankcase and the brackets: Crankcase Catastrophe. Making new brackets and fixing those brackets required a special countersink extension.
    • Studs – aligning and fixing the cylinder to the crankcase.
  • Cylinder – machining the cooling fins is not so easy.
    • Head – I started with an aluminium head and after lots of machining swapped to steel.
    • Liner – a mild steel liner
  • Flywheel – simple mild steel flywheel
  • Piston – a cast iron piston and liner, a great pairing.
  • Spark Plug – I bought a 1/4″ x 32 plug.
  • Timing Gears – machined by me on the Hobbymat

The build to date is shown in the video below where I talk about the engine and then take it apart.

I’m listing all of the parts of this poppet valve single cylinder engine as I move through the design and build stages. This does mean that I’m having some issues and the occasional complete catastrophe, but I hope this process is of interest in it’s own right.

1 thought on “Poppet Valve Single”

  1. Man I had no idea of this model engine building was that intense. No I’ve got a Bunch of little wood pieces, was contemplating try that.Cant stop reading your pieces, GREAT JOB.


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