Storage of engine brings new life

This is a friends engine which has been stored for over a year upside down in a box.
When purchased it would not run and clearly needed a strip down. This was the the result of a run on air a different engine.

 Runs like a new machine!   Any idea of the cc's?
  

The engine is a four cylinder engine of 10 mm bore x 20 mm stroke, double acting.
The design of the engine is by the Swedish Jan Gunnarson.
The complete steam plant is published on the book "Steam and Stirling edited by William C. Fitt.
In 53 pages packed with detailed machining descriptions and photographs of the step by steam construction of the full plant: engine, reverse block, lubricator, engine driven pump; boiler, burner, hand pump, exhaust steam feedwater heater, and all the boiler accessories: safety valve, water gauge, safety valve, check valve, bypass valve, stop valve. Maybe I missed something.
This is probably the most complete steam project that I have ever run into and I strongly advise all steam model engineers to check it up for its wealth of informations.
The author (who died quite recently) was one of highest reputed steam engineers.

 Hello!
Here is a nice subject for Eolipyle!
Cheers!