Ex Air ministry Alcon Pumps

[davidbliss]

Andy
On both pumps there are non-return flap valves just inside the threaded suction hose connection, so not really foot valves but do same thing not on the pipe, and both pumps are sort of the same, the faster priming one has a smaller water re-circling jet and different housing where the ball fits. I did take it into Panks and they said never seen one like it and with difficulty of fitting a modern seal fitted the same type back from the other pump but that soon leaked again and swapped the crankshaft as was a little better and that’s been ok since, did put a drain hole so if it leaked again water wouldn’t be so likely to get into the oil, did the same but larger hole to the other when the left over’s were assembled, there are many differences between those engines as one has several extra bumps and the odd plugged hole for something, different valve chest thats sort of open, with a very heavy grove in the cylinder bore that goes round about a turn nearing bottom of piston stroke and the other is a much better engineered looking thing so what came first. The well used engine is numbered 36812/40 and the other has the Alcon plate 2334/132 so similar stampings, so crude in one part but better made in another. Was told who knows? Being Air Ministry was done for experimental or special job?.

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[andyfrost]

David , the groove you refer to was an idea/design that JAP toyed with for a short period , it was also used on 4/3 , 5 models , but was quickly dropped. So in it’s original format that engine would have been fitted with a carb with the JAP logo cast into the fuel bowl , it was a very similar looking carb to the Zenith13. Traces of yellow paint on the carb in one of your pics tells us quite clearly that it is a mixture of old/new bits and pieces.

Andy

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