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).
Tests of a Large Bore Bentley fitted with Large Carburetters, comparing needles, pistons, and cylinder heads.
| Identifier | ExFiles\Box 82\4\ scan0199 | |
| Date | 13th December 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/FD.{Frank Dodd - Bodies}23/KW.13.12.35. Large Bore Bentley fitted with Large Carburetters. We have carried out a series of tests on the large bore Bentley to determine the best needles for production and also the effect of damped pistons. The best all round results were obtained with LB-2 needles. No advantage was gained by damping the pistons, and we could not detect any improved feel of better power. The attached print shows the acceleration figures with a 6.8 : 1 cylinder head and also the proposed standard head 6.44:1. With the present standard ignition governor, using a 6.44:1 cyl. head, and running on Shell No.1 the engine is very good for absence of pinking. With the 6.8:1 cyl. head, detonations are most objectionable. There is no difference in the times for Ticknall Hill with the two cyl. heads. Running side by side the cars were level up to 60 M.P.H. Traffic conditions would not permit faster speeds side by side. B-23-AE was fitted with 6.8 : 1 cyl. head and 1-B-IV a 6.44: 1 cyl. head. Both cars were equal weight - 33 cwts. and driver. Hs{Lord Ernest Hives - Chair}/F.Dodd. | ||