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).
Engine overheating, petrol boiling, and potential solutions including outside air intakes and radiator improvements.
| Identifier | ExFiles\Box 91\4\ scan0066 | |
| Date | 3rd July 1935 | |
| -2- (3) It may be necessary to go to an outside air intake to keep the petrol from boiling in the float chambers. Cadillacs of course use an outside air intake. At 60°C. we lose about 10 HP. due to the high under bonnet temperature, which is in itself a consideration. We started to carry out some experiments on the Bentley with an outside intake, but this appeared to some extent to upset the carburation. We are repeating our tests in view of the possible requirements of the SpectreCodename for Phantom III. We are asking G.W.H. to try out an outside air intake at Chateauroux. (4) Our oil is now cooled by the car radiator. We are getting Hancock to measure the oil temperature when the cooler is out of action. (5) Though we boiled on the Stelvio we did not lose any water until we undid the anti-spill radiator cap. It would appear that whether we boil climbing the Stelvio in the middle of Summer or not, we may not be able to afford a larger radiator matrix, because if we fit a more efficient matrix we are likely to accentuate vapour lock. Therefore the anti-spill radiator cap becomes of more importance than on any of our other cars to prevent loss of water. The Camel type you have issued should be O.K. The object of this memo. is to prevent undue alarm at the repeated mention of overheating in Hancock's reports, and to indicate that there are reasons why this first car should be worse than the next car which is going out. Furthermore, that we have had a lot of past experience with overheating and see nothing insuperable about the problems encountered though the Vee 12 cylinder engine is undoubtedly more difficult than the 6. HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||