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).
Comparison report between the experimental 6.B.IV Bentley and the standard B.2.LS model during trials.
| Identifier | ExFiles\Box 83\2\ scan0135 | |
| Date | 12th November 1937 | |
| File WOA Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux}3/MH.{M. Huckerby}12.11.37. 6.B.IV BENTLEY. Comparison with London trials Bentley B.2.LS. When 6.B.IV was tried by Cx{Major Len W. Cox - Advertising Manager}, their trials Bentley was taken for comparison, and I had to bring this car back to London while Cx.{Major Len W. Cox - Advertising Manager} proceeded with 6.B.IV for the remainder of his run. I therefore had the time and opportunity to draw comparisons for myself and make notes at the time, also to get an idea of what a Standard production Bentley is really like. (1) The engine of the standard car was less noticeable. While this may have been partly due to better dashboard insulation, a newer car, and a more kindly treated engine, the valve gear was definitely quieter and there was no noticeable valve bounce in contrast to that which comes in badly at 3800 r.p.m. on 6.B.IV. This has been demonstrated to Rm{William Robotham - Chief Engineer}/CTS{C. Trot Salt - Carburation} and reported to Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} who are investigating and dealing with the trouble. (2) The standard clutch was less smooth on engagement than the Thermoid clutch on 6.B.IV. The heavier pedal pressure was most unwelcome but the shorter travel of the standard pedal was an improvement for comfortable operation. 6.B.IV has the best pedal servo we have tried. (3) Transmission rattles on torque reversal and sudden clutch withdrawal could be produced on B.2.LS but were considerably less severe than 6.B.IV. We attribute this to the propeller shaft damper, and probably closer clearances in the new gear box of the standard car. (4) The most marked difference between the two cars was the low speed ride. 6.B.IV will have to be considerably improved to bring it up to standard. (5) It was impossible to put the standard brakes on hard on slippery roads without the tail coming round. 6.B.IV would pull up perfectly straight in a very much shorter distance, and was shown to be safer and more controllable under slippery conditions. | ||