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).
Specification details for the Bentley 50 engine following a planning conference.
| Identifier | ExFiles\Box 111\2\ scan0262 | |
| Date | 17th November 1937 | |
| 1044 To By.{R.W. Bailey - Chief Engineer} from Da{Bernard Day - Chassis Design}/JNR.{Charles L. Jenner} 860 Da{Bernard Day - Chassis Design}/JNR.{Charles L. Jenner}7/MH.{M. Huckerby}17.11.37. c. Rm.{William Robotham - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Swell Please note & add any comments Rm{William Robotham - Chief Engineer} BENTLEY 50 ENGINE. As a result of the Conference to consider and examine the projects and the planning done on the above engine, the specification was decided by By.{R.W. Bailey - Chief Engineer} as follows. Size and Type. That the conventional engine and the power engine should be 3½ litres, and that the lower half of the engine from the tappets downwards should be common to both, Crankshaft. Wraith dimensions with aluminium big end bushes 2" pins. Packard type balance weights 100%. Crankcase and Cylinders. Monoblock cast iron with long water jackets and the banjo clearances made fairly close. No extra clearances to be provided for the possibility of larger big ends. The horizontal joint to be below the centre line, but no lower than is necessary to make the joint with the rear bearing cap. Conn Rods. As Wraith, machined all over, but having larger diameter bolts which then can be made from commercial steel. Cylinder Head. Compression ratio 6 to 1 as Wraith. Four inlet and four exhaust ports on the same lines as the scheme sub-mitted by Da{Bernard Day - Chassis Design}/McStay, but keeping the exhaust port shape continuing rectangular after the restriction point imposed by the push rods. | ||