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).
Issues with the Bentley J.III crankshaft and the number of main bearings.
| Identifier | ExFiles\Box 103\3\ scan0176 | |
| Date | 31th July 1933 | |
| X5670 To Wor.{Arthur Wormald - General Works Manager} From Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} a.{Mr Adams} c. Hy.{Tom Haldenby - Plant Engineer} b. Ev.{Ivan Evernden - coachwork} d.{John DeLooze - Company Secretary} Bh. Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer}4/KT.31.7.33. J.III CRANKSHAFT. Our troubles with the Bentley now seem to be concentrated on the crankshaft. The symptoms are loose flywheels and broken slipper wheels. Actually we know that under road conditions we are perfectly safe, but there is no doubt that the seven bearing crankshaft on the 6-cylinder engine will prevent us from improving our power output appreciably. We think, in view of our knowledge, that it is a grave mistake to make the redesigned J.III with a seven bearing crankshaft. Actually it has a worse bore stroke ratio than the existing Bentley for crankshaft master period. There is not much doubt that, as soon as we have developed this engine, we shall find the crankshaft master period is the limiting feature. We are certain that a reduced number of main bearings is essential in any new 6-cylinder engines we may produce. Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} | ||