Update on the pressure testing…
Because the bicycle tyre did not show any bubbles at all I made a different set up. Blocked off one hose and made a stop for the other hose in which I incorporated the valve from the bicycle tube. And in the water it went again. Now only one or two pumps of air were sufficient to show bubbles in three separate places! At the LH and RH rear (both known leaks) but no leak at the RH side ferrule (were the water was when the bike stood for a while), no matter how much air I put into it. But also no leak in the exhaustport etc. So this test at least worked.
It also showed a new leak between the two cylinders at the front (behind the waterpipe). A closer look revealed that the block was cracked over both cylinders and soldered up. And this leaked…. So I soldered it up again (or twice to be precise as it was very difficult to get the solder to stick on the 80 year old cast iron). Hopefully it is watertight now.
The LH ferrule that came loose earlier when unscrewing the plus was now so tight that I could not remove it, even with considerable force. So I left it in place.
To fill the gap between the waterdome and the barrels I turned two aluminium rings of the right size. I installed those with silicone gasket thus also sealing all leaks that might still be there around the ferrules.
This rings also enabled me to fully tighten the ferrule nuts without the chance of distorting the waterdome. I only hope I have calculated/measured the thickness of the rings to be the right size. I measured the gap between the waterdome and the barrels and compared this to the cork gaskets I am using (the thick, 1,9 mm version) and turned the rings somewhat smaller in order to be able to compress the gaskets a bit on installation.
I hope to do another pressure test before installing the engine back in the frame. So to be continued…
