The Brooklands Workshop manual says:
The course of oil from the sump is as follows:
Upon being drawn up the suction pipe, the mouth of which is situated about 1/4 inch from the bottom of the sump oil passes through a gravity operated ball valve to a gear type pump. From here it is fed under pressure to a gallery case in the cylinder block and in turn by branch ducts to the main bearings of the crankshaft, which, being drilled, permits oil to be conducted to the connecting rod big-ends.
If this is what you're after it will be the only useful thing I've ever found in the book!
