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).
Diagram showing cylinder bore wear measurements and analysis at different mileages.
| Identifier | ExFiles\Box 131\2\ scan0293 | |
| Date | 25th October 1938 guessed | |
| .300 3.800 .375 CROWN LARGEST DIAMETER CENTRE MOUTH AVERAGE BORE WEAR OF 10 CHASSIS OVER 20,000 MILES AVERAGE BORE WEAR OF 10 CHASSIS OVER 30,000 MILES TABLE 1: | | MOUTH | CENTRE | CROWN | |---|---|---|---| | 3½" L | 0003 | 0018 | 0045 | | 4¼" L | 0005 | 002 | 0046 | TABLE 2: | | MOUTH | CENTRE | CROWN | |---|---|---|---| | 3½" L | 0005 | 0025 | 0059 | | 4¼" L | 0005 | 0020 | 0053 | MOUTH & CENTRE MEASUREMENTS TAKEN AT "A"-"A" (PRESSURE DIAM) AND "B"-"B" (PARALLEL WITH C/L SHAFT) LARGEST DIAM RECORDED IS USUALLY ON DIAMETER "X"-"X" | ||