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).
Letter discussing Bentley valve clearance settings for Continental conditions and arranging tests in France.
| Identifier | ExFiles\Box 82\2\ scan0095 | |
| Date | 20th July 1934 | |
| 4553a Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}10/KW.20.7.34. G.W. Hancock, Esq., Hotel de France, Chateauroux, Indre, France. 18th July. Many thanks for your note of the We understand that Ethyl petrol is now widely distributed in France but may be mistaken. We have a test which we should like you to carry out. The present instructions on Bentleys with the K.E.965 exhaust valves are to set the valves at .004 inlet and .006 exhaust. We know that this is your general practice on the Continent but it undoubtedly makes the Bentley valve gear exceedingly noisy. Previously the Test Dept. have always worked to .003 inlet and .004 exhaust. We should like you to run your car with the exhaust valves at .004 and see whether under ordinary road conditions this causes all the clearance to be taken up. We admit that for Continental conditions we should always recommend .004 inlet and .006 exhaust but it seems unfortunate that all Bentley owners in England should be penalised with noisy valve gear in order to enable a customer occasionally to undertake a Continental tour at high speeds. Generally speaking there is not much difficulty in instructing Paris to set tappets wider than English standard and so take care of the ordinary Continental owner. 21-G-IV will be crossing by the Townsend service on Tuesday morning. We are sending Grylls and an assistant with the car. Grylls has never previously been to Chateauroux and it will be useful for him to see how the cars are run. Both cars are fitted with experimental clutches and brakes in which he is particularly interested. We expect him to be at Chateauroux for about three weeks and will then send somebody to replace him. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||