Pressure relief ball

[Steve kay]

This particular magneto engine being an assembly of new and properly sorted components, no plugs had fallen into the crankcase. This person however has learned something very very important indeed. Don't just count the number of valves, and the correct torque for tightening cylinder  head nuts, but peer into the gloom alongside the oil pump and check that both the blanking plugs are still there! Whilst plugs are offered on web sites, doubts have been expressed about their origins and correctness. However, whilst Denny's Shipyard in Dumbarton long since closed down, two elderly chaps are still in a shed behind what used to be the prototype shop. There, on belt driven Drummond lathes they will make suitable items to correct spec, and a distinguished Scottish Seveneer has commissioned a plug or two.  Full report in due course, the apprehension being why one plug is missing, and whether the replacement can just be screwed in or further work must be undertaken.