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).
Oil consumption and crankcase pressure tests with a 30 HP type oil filler, comparing results with and without a rocker cover breather.
| Identifier | ExFiles\Box 82\5\ scan0090 | |
| Date | 21th April 1937 | |
| MTHS{Reg Matthews} Swaff HOTEL DE FRANCE, CHATEAUROUX, Indre. France. 21st April 1937. To. Rm.{William Robotham - Chief Engineer} GWH{George W. Hancock - Head Chateauroux} 200a S. B. IV. Oil consumption tests with 30 HP.type oil filler with crankcase breather. a) Two runs each of 166 miles over a give and take route, driving hard. Average speed 46 MPH. Petrol consumption 12.6 m.p.g. 1st Run. With no breather to valve rocker cover. Oil consumption 885 m.p.g. 2nd Run. With standard breather from rocker cover to air silencer. Oil consumption 759 m.p.g. b) Two runs each of 160 miles over an easy route at high speed with gentle driving and light throttle. Average speed 49.5 MPH. Petrol consumption 13.8 MPH. 1st Run. With no breather to valve rocker cover. Oil consumption 1444 m.p.g. 2nd Run. With standard breather from rocker cover to air silencer. Oil consumption 1304 m.p.g. The runs show a 16.6% improvement with hard driving, and a 10.7% improvement with gentle driving when the rocker cover breather is deleted. Crankcase pressure tests with 30 HP.type breather. These tests were all taken at full throttle, as this gave the highest pressures. At no time was a depression in the crankcase recorded. The pressures are of a very small order 0.5" of water or 0.018 lbs/sq". and can therefore only be regarded approximately. I) With crankcase breather and rocker cover breather. Speed. 20 30 40 50 60 70 80 90. Pressure ) in inches of water.) 0.2 0.2 0.3 0.3 0.3 0.3 0.3 0.3 | ||