Joe Webster designed this engine to be quick, inexpensive and easy to build. It doesn’t have any parts with super-critical dimensions and you don’t need a rotary table or other expensive tooling to construct it. The plans are well drawn and include two pages of construction notes.
This is what is known as a “bar stock” engine, which means it does not use any castings. It uses flat and round metal stock that can be purchased from almost any metal or machine shop supplier It is not a big engine so the cost of the metal should be modest. Joe suggests making the 3.75-inch diameter flywheel out of an iron dumbbell purchased from Wal-Mart to save money.
The engine uses some components that need to be purchased, like a couple of gears, a spark plug, points, condenser, ignition coil and piston rings. The part numbers and vendors are listed on the plans and they are all readily available, I’ve checked. Joe recommends you also buy and use a carburetor for a radio-controlled car engine, although he does include drawings so you can make one if you want.
Unfortunately, Joe’s website seems to have disappeared but you can still download the plans here.