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).
Summary of work and average wear figures for cylinder bores on various engine models.
| Identifier | ExFiles\Box 103\2\ scan0030 | |
| Date | 11th March 1939 | |
| GWH{George W. Hancock - Head Chateauroux} To Hy.{Tom Haldenby - Plant Engineer} from Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} c. Hs.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} CYLINDER BORE WEAR. The following is intended to be a summary of the work carried out during the past twelve months on cylinder bore wear on our chassis engines; the conclusions obtained there-from and our programme for the immediate future. The following average wear figures have been obtained by tabulating the various models coming into London Depots during the last six months. 20/25 H.P. Average wear = .00015"/1,000 miles. 25/30 H.P. Average wear = .00015"/1,000 miles. Phantom II. Average wear = .000092/1,000 miles. Bentley. Year. 3½ litre at 20,000 miles = .00022"/1000 1935.) " " " " " = .00022"/1000 1936.) " " " " " = .0002"/1000 1937.) " " " 30,000 " = .00022"/1000 1938.) " " " " " = .00015"/1000 1937.) " " " " " = .00017"/1000 1938.) 4¼ " " 20,000 " = .00031"/1000 1937.) " " " " " = .00025"/1000 1938.) " " " 30,000 " = .00016"/1000 1937.) " " " " " = .0002"/1000 1938.) | ||