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).
Up-to-date report on the Bentley B.80 8-cylinder engine, detailing issues, proposed solutions, and performance comparisons.
| Identifier | ExFiles\Box 123\5\ scan0319 | |
| Date | 23th February 1939 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. HS.{Lord Ernest Hives - Chair} c. DA.{Bernard Day - Chassis Design} c. RHC.{R. H. Coverley - Production Engineer} c. AX. c. DA{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} c. DA{Bernard Day - Chassis Design}/KCS. RM{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}1/MH.{M. Huckerby}23.2.39. BENTLEY B80 UNIT (8-CYLINDER). We give herewith an up to date report of the B.80 unit which is confined to No.1 unit. As a new job this engine promises very well, although we have had the advantage of the cylinder head experience on B.60 which enabled the B.80 to be started off under the best conditions. So far as we have gone, the major problem of the unit is the crankshaft oscillations, as we know that with similar amplitudes on the B.60 the teeth of the fibre camwheel fail. The above resolves itself into the necessary provision of a spring drive combined with harmonic damper. Regarding the cylinder head, it is proposed to carry out the development of the head on the B.60 unit, and any features of the experiments which are found to be an improvement are then to be incorporated on B.80. PERFORMANCE. The attached curve (Rm.{William Robotham - Chief Engineer}583) shows a comparison between the B.60 and B.80 and although there are several variables on the two engines, including camshaft and induction systems, it does give some form of basis for the relative performance of the two engines. So far as maximum power is concerned, the B.80 (8-cylinder 5.2/3 litres) developing 172 BHP at 3750-4000 R.P.M. is pro rata with the B.60 (6-cylinder 4 1/4-litres) giving 128 BHP at 3750-4000 R.P.M. A maximum MEP of 125 lbs. per sq.in. at 2000 R.P.M. is developed on the B.80 as against 131 lbs/per sq.in. on the B.60 unit. | ||