Is aluminum/iron casting beyond the scope of the home workshop?

Not for small aluminium parts, but it takes years of practice to be able to cast something as complex as the parts you'll need. Also something the size of a crankcase is going to be hard to do in a home sized furnace. Making a furnace big enough is a challenge in its own right! And thats just for aluminium, iron/steel is a whole new ball game.

Whilst I applaude your efforts and ambitions (as someone who often bites off more than he can chew) I do wonder about your understanding of the complexity of the challenge. You are focusing opn the design and machinining of parts, but that is just the tip of the iceberg. I have some small experience of engineering and materials analysis from past experience of designing cold-wall heat-exchangers for cooling military equipment and I wonder how/when you are going to do the materials analysis and heat/cooling analysis to determine whether your design will work (clearances across temperature gradients, etc.) or will simply seize at the first run or, worst case, melt itself into oblivion...?


Personally, before you go much further, I would suggest you invest in a small mini-lathe and mill and see if you can make a working model of a single pot 2-stroke or steam engine to one of the many designs on the web. That'll give you far more insight into the skills/expertise needed than any questions on here.