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).
Report discussing the influence of oil grades on engine starting performance, with conclusions from tests on a Standard 16 HP car.
| Identifier | ExFiles\Box 145\1\ scan0124 | |
| Date | 13th December 1934 guessed | |
| Y56-12948 No. 2. V.O.Co., Ltd., to Starter current is also given for each test on the different grades of oil, and in the next column starter motor speeds - the starter gear ratio being 89-11. The influence of the summer and winter grades of oil with the corresponding advantages of the latter, will be fully appreciated, Mobiloil "A" and "AF" being the recommended winter grades for the majority of popular cars made in this country. With regard to the column 6, Table No.2., and the lower speeds recorded with condition "A", it should be noted that the clutch withdrawal was of the carbon block type. A comparison of the torque at the motor shaft of the starter motor (Table No.2., column 12), may be made with the torque shown on page 30 of the N.P.L. tests with suitable allowance for reduction gear losses. Table No.3. shows the laboratory readings of the used and unused oils and below them the gearbox oil, which is considerably lighter than is normally employed - the gearbox being the normal four speed sliding type. We fully anticipate that different results might have been experienced had some other type of gearbox been employed. May it also be noted that a new fully charged battery was used for these tests for obvious reasons, but this is probably an exception in winter once the car has left the factory, and starting conditions are therefore so rarely favourable. Conclusions. The Standard 16 h.p. car was selected as a typical 6-cylinder model, representative of a popular type available at the time, and also because the engine had been subjected to previous endurance and cold starting tests at the N.P.L. earlier in the year. It is generally recognised that 50/60 r.p.m. is the minimum crankshaft speed at which the average 4 and 6-cylinder engine will start up from cold, when using good quality fuel and with the ignition and carburetion in proper order, so it will be seen from Table No.2. that the recommended grades of oil for winter give considerable assistance. There is also less drain on the battery, apart from the added advantage of more rapid oil circulation with (Cont'd) | ||