BOOK (not sure on others) – The “HP Valve Chest Face” drawing shows 5 ports. The upper one is shown in error – there should only be four ports in 2 symmetrical pairs. This would be a a disastrous error and mean scrapping the casting. The drawings variously number the HP valve chest as 3d and 3a. Submitted by Malcolm D
John Olsen comments “I didn’t like the porting on the HP valve to get the steam from the end to the middle, so both of my piston valves have an end cover top and bottom that provides a connection for a decent size external pipe. This is based on the idea that a decent size connection to get the steam out is often more important than getting the steam in.” editor’s note: To avoid confusion I should explain that John fitted piston valves to HP and LP on his engine, hence his “both valves” comment.