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 rates and sump capacity for 3½ and 4¼ Litre Bentley cars.
| Identifier | ExFiles\Box 144\3\ scan0153 | |
| Date | 28th January 1937 | |
| 1220 W/S. To H.{Arthur M. Hanbury - Head Complaints} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}11/AP.28.1.37. OIL CONSUMPTION ON BENTLEY CARS. In reply to the memo H.9/HS.{Lord Ernest Hives - Chair}5.1.37. with regard to customers who have to replenish the sump with oil once or twice during a week-end run of 500/600 miles, we should like to pass the following comments. Normally filled up, the sump holds 1½ gallons and it is safe to run down to ½ gallon before the pressure becomes erratic under normal driving due to the swilling of the oil away from the filter inlet, when braking or accelerating. This means that there is one gallon available for the engine consumption. Taking your out-side week-end case of 600 miles, then if the consumption is 600 miles/gallon or better, the journey can be carried out without a refill. If a customer refills twice, then without using any oil out of the sump after the second re-fill he has used 2 gallons, assuming that the journey was commenced with a full sump of 1½ gallons. In such a condition, the consumption would therefore be 300 miles/gallon and if this is so, then it is time that the unit recieved some attention, for a normal consumption for Bentley should be approximately 800 miles/gallon. Under extreme conditions where a long journey is to be carried out without desire of refilling, the sump can be overfilled the gauge reading by ½ gallon only, without trouble, this making 2 gallons in the sump. There would therefore be 1½ gallons available for engine consumption and assuming the car is bad for oil consumption and doing say only 500/miles/gallon, then a journey of 750 miles is possible without having to refill. Other than the above conditions, which apply solely to standard 3½ and 4¼ Litre Bentleys, tests are being carried out with a view to further improvement in oil consumption, without running into risks of seizing etc. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||