Here is an entry level, beginner model engine that you can build with a small lathe and drill press.  Of course, if you have more machinery, such as a small vertical mill it could be easier, but this engine does not require it.  This design is based on small and easy to make aluminum castings!  It is a scratch build, minimal purchased components and you wind up with a running model engine.  There are six pages of drawings and text.  

On a scale of 1 to 10 I would rate this engine as a solid 5, advanced beginner who is tinkering with aluminum sand casting.  It is well within the range of a Unimat or similar small lathe, of course a small bench lathe like available from Harbor Freight would work nicely.  It is not too complicated and not too many parts to make so it is a good entry level model engine project.  It is spark ignition and two cycle and would make a nice model boat engine.

It is an easy to follow set of plans and if you are aspiring to build your own model engines, this is a great selection?  Get this one under your belt and then move on to more sophisticated engines like the Wall 1 hp single air cooled or if you really feel ambitious, try a Wall 4 cylinder!

In our store we also are offering the book "model gasoline engines" on CD-ROM, (pdf) and, other model engine drawings sets,  The MORTON M-5 drawings on CD-ROM and other model engine / hit & miss related items! We also have repair manuals for lots of small commercially built engines.  If your interests run along history of model engines these items are definitely for you.