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).
Comparing two cylinder head designs, including diagrams and specifications for valve timing and compression ratios.
| Identifier | ExFiles\Box 134\1\ scan0115 | |
| Date | 23th December 1938 | |
| -3- Reverting to the high power head (No.5) which is similar to B.60, the Curve (a) confirms within 2%, to that given in Rm.{William Robotham - Chief Engineer}2/R.14.12.37 (Fig.II). Likewise the power given with the Bentley cylinder head and Bentley timing approximates to a curve under similar conditions in the above memo, (Fig.III). This particular head had 1.4 inlet valves, 1.3 exhaust and valve timing of 104°BTDC - EO51°BBDC and 6.4 : 1 compression ratio. IC51°PBDC - EC7°PTDC [Left Diagram] No 1a No 5 HEAD 6.4:1 RATIO [Right Diagram] No 2a BENTLEY HEAD 6.6:1 RATIO 1.5 INLET 1.4 EXHAUST | ||