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 to Leyland Motors discussing crankshafts, raised crown pistons, and their effect on compression ratios and detonation.
| Identifier | ExFiles\Box 140\3\ scan0257 | |
| Date | 20th September 1939 | |
| 1175 Rm.{William Robotham - Chief Engineer}4/MH.{M. Huckerby} 20th. September, 1939. V.W.Pilkington, Esq., Leyland Motors Ltd., Leyland, LANCS. Dear Pilkington, Many thanks for your letter of the 18th. September together with the report on crankshafts, which is very interesting. The result you obtained with the raised crown piston is rather curious. The results we obtained were that we were able to run at a higher compression ratio for a given degree of detonation. Naturally, the fact that we were running at a higher compression ratio made the engine slightly more sensitive to ignition setting. There is no claim for more power at the same compression ratio. The pistons which Wellworthy's made for you were supposed to give you about half a ratio higher than standard. Presumably you took compression pressures to confirm that you were getting the benefit of the increased compression ratio. I would like to come up to Leyland on Friday of this week before our petrol rationing starts, and look over your figures. Yours sincerely, | ||