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).
Modifications to air pump, oil pump gear, and piston designs, comparing American and English production methods.
| Identifier | ExFiles\Box 29\2\ Scan066 | |
| Date | 1st November 1922 guessed | |
| - 6 - (B). Modifications made to enable them to produce with sufficient accuracy by different methods from those adopted in England. (1). Air Pump design modified. Flat valve is used instead of a conical seated valve with the object of allowing the cylinder to be broached, as they could not obtain the accurate fits we called for in America by grinding. One does not consider the flat valve is good for air retaining as a conical one. (2). Design of Oil Pump Gear modified. The helical teeth are used for the Oil Pump instead of plain spurs, the reason being that America were unable to obtain spur gears cut sufficiently well to run. Derby have, however, recently sent along a scheme shewing how we have been able to overcome the difficulty in question. (3). Piston. The length of the piston has been increased with the object of stopping piston knocks and seizing up. EP.{G. Eric Platford - Chief Quality Engineer} did not consider the lengthening was beneficial in any way. We do not think the extra weight is noticeably detrimental, but certainly feel the trouble with the pistons was due to the faulty work which Springfield thought they could counterbalance by having a longer skirt. | ||