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 50,000-mile test for the Bentley V, detailing engine components including pistons, cold starting, distributors, and valve springs.
| Identifier | ExFiles\Box 161a\3\ scan0129 | |
| Date | 21th April 1939 | |
| - 7 - BY.1/G.21.4.39. BENTLEY V.{VIENNA} 8.B.V. 50,000 MILES TEST. Consideration of Rm.{William Robotham - Chief Engineer}3/R.22.3.39. and Mx.{John H Maddocks - Chief Proving Officer}1/MG.15.4.39. ENGINE. PISTONS. We are adopting the type of piston with a raised portion head, which fits into the combustion chamber. This piston has completed 50,000 miles as 7 to 1 ratio on 8.B.V. and is fitted on all Bentley V.{VIENNA} engines. At 7 to 1 the detonation is no greater than 6½ to 1, with the dd type piston. COLD STARTING. Further work has been done in connection with starting the engine from cold. As the result of modifications made to the original system tried, which comes in automatically when the engine is cold, it is now considered that the new scheme justifies its introduction on the first of the B.5. production cars, and has enabled us to remove the hand control for starting from the steering column. DISTRIBUTORS. We have a Rolls-Royce distributor on test, which by using a three lobe cam and two make and break levers, enables us to give the same ratio of 'make' or closed current condition with our distributor as is possible on the Delco. In addition, we have a modified governor as a further development, which follows the Lucas and Delco system as being less costly than our own. VALVE SPRINGS. No further failures of valve springs occurred after those reported at the previous Conference. Mileage covered since breakage without trouble 20,000. A design was issued and detailed, but has not yet been tried. Lack of room prevents the stresses being reduced very much by the double springs. Double valve springs on the B.60 showed no improvement. | ||