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).
List of measurements for bellows length and valve lift under various conditions.
| Identifier | ExFiles\Box 156\2\ scan0038 | |
| Date | 12th March 1938 guessed | |
| Bellows length(on maker's label) in free position - 1.437 " " (measured after 450 miles running) - 1.530 in free position. " " as received fully compressed - 1.280 Valve lift - after release of charge after - .137 450 miles. " " - bellows top plate touching - .280 bypass seating. Initial pull up of bellows in casing - .125 ------ | ||