From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Technical comparison of pump specifications, performance characteristics, and testing procedures.
| Identifier | ExFiles\Box 27a\2\ Scan217 | |
| Date | 26th July 1933 | |
| -2- Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey}3/KT.26.7.33. depress the plunger so that the diaphragm is at the bottom end of its maximum travel, before tightening up the screws holding the two halves of the pump and the diaphragm together. On their pumps the diameter of the pitch circle of the screw holes in the diaphragm is .0625" greater than that of the holes in the casing. Valve Lift. The A.C. pump has .070" valve lift; the lift on our pump is greater, but this they say is unimportant. Diaphragm Stroke. The optimum stroke is .250", i.e. as our pump. Valve Seats. Valve seats should be very carefully lapped. Air Bottle. On the A.C. pump an air bottle is not generally fitted, but in certain cases where a larger delivery is required, an air bottle less than half the capacity of ours is fitted over the delivery valve and is credited with increasing the delivery by 50%. Crankcase Heat. Experience has shown that it is not necessary to insulate the pump from crankcase heat. They investigated this some time ago and the pump output does not vary with temperature. Vapour Locks in Pipe Line. The only trouble experienced in this connection occurred on cars in Africa and was remedied by placing the pipes in a better position; in this particular case the trouble was due to heat from the road; the pipes being clipped to the under side of the bottom side member flange. Our Bentley layout of pipe line was explained to them and they said we should experience no trouble from this cause. Tests of Pumps. Every production A.C. pump is carefully tested before it leaves the works, the tests consist of (1) priming test, (2) High speed delivery test, (3) pressure test. The priming test consists of delivering petrol from a tank 3'6" below | ||