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).
Graph showing micrometer readings for valve-lifts against temperature, using a 20° valve and Castrol XL oil.
| Identifier | ExFiles\Box 151\2\ scan0387 | |
| Date | 21th February 1939 guessed | |
| VALVE-LIFTS USING 20° VALVE AND CASTROL XL MICROMETER READING (INCHES) .060 .050 .040 .030 .020 .010 .000 10 LBS/□" 80 MPH 20 LBS/□" 80 MPH TEMP °C 0 20 40 60 80 100 120 140 SHEET 2 | ||