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 conducted to investigate excessive oil consumption in the 25/30 model.
| Identifier | ExFiles\Box 144\3\ scan0105 | |
| Date | 11th August 1936 | |
| x 1220 To E.{Mr Elliott - Chief Engineer} C. to WOR.{Arthur Wormald - General Works Manager} C. to Hy.{Tom Haldenby - Plant Engineer} C. to Hx. Me/Swdl.{Len H. Swindell}S/JH.11.8.36. 25/30 Oil Consumption Tests. Following the excessive oil consumption figure, consistently obtained both on the production and experimental chassis of 300-400 miles/gallon a series of comparative tests were taken on the test beds. The main object was to effect an improvement without any alteration to the existing production piston so that there would be no hold up. Some surprising and useful information has been obtained which hitherto was more or less unknown, the effect of the rings on the oil control whilst reasonable oil consumption was being obtained being an accepted fact. In consequence very little work has been carried out on oil consumption until the trouble cropped up on the 25/30. It is generally known that from the results obtained in France, the consumption improves with the mileage and the bedding in of the rings and the trouble is during the first few thousand miles. The bedding in, only takes place to any great extent by high speed running and consequently a customer who never drives the car hard, never obtains the best consumption figures. The tests on the bed were carried out at a constant speed of 4000 R.P.M. both at full and half load. Under the above conditions at the commencement of a run with standard piston rings the average figure obtained ranged from 100-300 miles/gallon. By continued running up to an equivalent of 1,000 miles the figure improves by averagly 100% and then remains constant. | ||