Experience Levels

As a general rule, if you are new to machining and have not built any engines of any kind, you would be advised to build a few bar stock steam (air pressure) engines to develop a 'feel' for the accuracy of fit that engines require before attempting a hot-air or internal combustion engine. 

Hot Air Engines from Easiest to Hardest

1. Sideshaft Vacuum Engine
2. Mini Stirling Engine Fan
3. 4-In-1 Vacuum Engine
4. Super Stirling Engine Fan
5. Ringbom Stirling Pumping Engine
6. Vintage Stirling Pumping Engine
7. Duplex Vacuum Stirling Engine
8. Vickie Stirling Engine
9. Beamer Stirling Engine
10. Miser Low Temp Stirling Engine.

Do not let the above stop you though. Many Miser engines have been successfully built as a first project! It all depends on how particular and precise a builder each person is.

Internal Combustion Engines from Easiest to Hardest

1. PowerHouse
2. Bill
3. Farm Boy
4. Plunket Jr.
5. Howell V-Twin
6. Howell V-Four.

Note - The V-Twin and the V-Four engines are for builders who have previously built several successfully running I.C. engines. I do not recommended these for the novice, although some first time builders have completed very nice running engines.