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).
The weight reduction of Phantom II inlet valves through various modifications.
| Identifier | ExFiles\Box 17\6\ Scan132 | |
| Date | 26th August 1933 guessed | |
| WEIGHT OF PHANTOM II. INLET VALVES. Weight of original Inlet Valve R.83904. LeO 3446. 6.53 ozs. ---------- Weight of Valve with tulip portion of head modified to EX.11887. LeC.3579. 5.66 ozs. ---------- (These valves have previously been modified by removing step on the head adjacent to seating). ---------- Weight of Valve when further modified by drilling a .156" diameter hole up the stem in accordance with EX.12011 5.32 ozs. ---------- The figures below indicate the reduction in weight at the different stages of modification :- With modification to tulip portion of head to LeC.3579 and removal of step adjacent to seat. .87 ozs. ---------- By drilling stem to EX.12011 .34 ozs. ---------- With all modifications incorporated. 1.21 ozs. ---------- | ||