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 analysis and load testing results for three types of valve springs from a B.3. unit after extended mileage.
| Identifier | ExFiles\Box 82\5\ scan0185 | |
| Date | 16th June 1937 | |
| VALVE SPRINGS. B.3. UNIT. THE ABOVE UNIT, WHICH HAS BEEN DISMANTLED AFTER 16,900 MILES IN FRANCE, WAS FITTED WITH 3 DIFFERENT TYPES OF VALVE SPRINGS AS FOLLOWS:- NºS 1-4 EB 175 SPRINGS PRODUCED IN U.S.A. NºS 5-8 EB 3256 SPRINGS SWEDISH HEAT CARBON STEEL (CLOSED END TYPE) NºS 9-12 RM.{William Robotham - Chief Engineer} 260 SPRINGS PRODUCED BY THE TEMPERED STEEL Cº. (SIMILAR TO EB 3256 EXCEPT IN MATERIAL) | TYPE | LOAD COMPRESSED TO DRAWING | AFTER TEST | LOAD LOST | |---|---|---|---| | EB 175 PRODUCED IN U.S.A. 1-4 | 56 LBS ± 14 OZS | 45 ¾ | 10 ¼ | | | | 46 ¼ | 9 ¼ | | | | 45 ¾ | 10 ¼ | | | | 46 ¾ | 9 ¼ | | EB 3256 5-7. | 45 LBS ± 14 OZS | 43 ¼ | 1 ¾ | | | | 42 ¼ | 2 ¾ | | | | 41 ¾ | 3 ¼ | | NEW SPRING -> 56 (EB175) | | 45 ¾ | 10 ¼ | | RM.{William Robotham - Chief Engineer} 260. BY TEMPERED STEEL Cº. 9-12. | 45 LBS ± 14 OZS | 41 ½ | 3 ½ | | | | 40 ¾ | 4 ¼ | | | | 40 | 5 | | | | 39 ¼ | 5 ¾ | Nº6 SPRING, EB 3256 IN SWEDISH WIRE, WOUND AT R.R., BROKE AT 3,322 MILES AND WAS REPLACED BY A STANDARD EB 175 SPRING. CAW 16-6-37 | ||