Hi John and Radiomike,
Our best guess as to the last time the engine may have ran would be the mid 1930s, it was purchased by a fisherman to put in a boat!!! Not suprisingly, it's rumoured the boat sank, it is extremely heavy and it wasn't used it then stood until late 1965 before it was purchased and paired with the bus. It is in amazing condition, turns freely, no rusty bores, and appears to be in good condition.
Indeed the junk rings seal the top of the bores, as they are a part of the head which projects down into said bore, the heads are a kind of upside down top hat so that the mating flange with the block is larger than the bore and allows for the head bolts and the water passage from the block. The water, we believe, comes from the pump, through an alloy manifold and enters the block, from the block it flows up through a connecting tube concealed within the block and the heads, fromthe heads it's through another manifold to the radiator, There is also a takeoff at this point which warms an atomisor unit that the carburettor is bolted to.
The gasket is shown as being between the mating surfaces of the head and block, we assume to stop possible corrosion between the surfaces, but as I say, the manual doesn't state what material it is. It's been suggested a paper gasket could be used, but we were wondering if anyone has stripped one of these engines and what they may or may not have found.
Thanks for your replies.
Pete.