Über Wilesco
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Safety Valves


Wilesco used two kinds of safety valves with different functional principle. First a lever safety valve with a weight at one end and second a spring safety valve. In era II until early era III the lever valve was the only safety valve at larger engines. Obviously it was also the only safety valve for larger engines in era I. Later on this type of safety valve was only used with engines for export until era IV or even era V. If the lever safety valve is used on export engines there is a filler
plug instead of the spring safety valve. Starting with mid era III until early era V this type of safety valve was used as whistle valve on larger engines and an additional spring safety valve was provided. If the change of safety valves is con- nected to the new safety regulations for toy engine boilers in 1970 is not clear. It seems that it was thought they be manipulable too easyly. The production of the combined lever safety valve / steam pipe endet 1984. Smaler engines used spring safety valves already in era I. The spring safety valves opens at a boiler pressure of 1.4 up to 1.6 bar (20 to 26 psi), the lever valves opens at pressures between 1.6 to 2.0 bar (23 to 29 psi).

Spring Savety Valve
  Era I



Spring Savety Valve
 Era II
 Era III bis Era V
 Era VI
 M5x1 M6x1 M6x0,75


There have been three different spring safety valves. They look very similar and differ only in the thread size. The diffe- rence between the second and the third type is not always obvious because some of the new engines with light blue ba- ses may be era V engines and an era VI valve will not fit. The thread diameter is M6 but the thread pitch is different. It is easy to ruin a thread in screwing in the wrong valve by force. BE CAREFUL.



 Lever Safety Valve with Whistle

until end  Era IV


 M6x1 oder M5x1




Filler plug used on older engines or export engines. There are some boilers for D8 and D10 engines of era III and era IV with an additional thread in the boiler top. This thread may be closed by a filler plug (M6x1) or a second spring safety valve. The production of filler plugs ended in early era V (maybe 1984). There is still a filler plug at marine steam engine boilers but I do not know exactly what kind of thread the era VI marine engine steam boilers use. 


  Filler Plug 



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Klaus Lutz | Roler0301@aol.com