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).
Performance graphs comparing different valve springs and push rod stiffness on a Phantom II valve spring rig.
| Identifier | ExFiles\Box 17\6\ Scan329 | |
| Date | 29th November 1934 guessed | |
| FIG. 3 PHANTOM II VALVE SPRING RIG No.1 INLET VALVE STANDARD CAMSHAFT E82448 ENGINE SPEED 3500 RPM (a) VALVE SPRING E81550 (b) VALVE SPRING E81550 (c) VALVE SPRING E81550 (d) VALVE SPRING E85666 Graph Labels: CLOSING ACCLN. REVERSAL HEAVY POSVE. OPENING Table: VALVE SPRING LOADS SPRING | SEAT LOAD | RATE E81550 | 70 | 96 E85666 | 85 | 155 Table: REL. PUSH ROD STIFFNESS (a) | 1.20 (b) STANDARD | 1.00 (c) | 0.75 Other markings: 12B 14B 16A° | ||