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).
Analysis of methods for reducing excessive engine oil flow, comparing Silver Ghost and Phantom models.
| Identifier | ExFiles\Box 182\M18\ img084 | |
| Date | 26th December 1922 guessed | |
| contd :- -2- feeds has proved to be a definite advantage when the oil flow is excessive. The average Silver Ghost with 20 to 25 lbs/sq.in. pressure at 1000 r.p.m. gives an oil flow of about .75 to .85 pts/min. while the Phantom with its normal oil pressure to 30 lbs/sq.in. gives from 1.8 to 3.3 pts/min. and in a particularly bad case on a worn engine we have observed a flow as much as 11 pts/min. METHODS OF REDUCING OIL FLOW. The two methods of reducing the oil flow on the Phantom (so that it is similar to the Silver Ghost) which suggest themselves are :- (1) Reduced oil pressure - and (2) Reduced bearing clearances. We have tried both methods and while the desired results can be obtained by each we feel sure that the latter is preferable and in fact the only reliable method at our disposal. With 'slack' bearings it is necessary to reduce the pressure to very low values, in some cases as low as 3 lbs/sq.in. in order to obtain the same flow as given by the Silver Ghost. Pressures as low as this are unpracticable and would leave open to chance some bearings receiving all the oil while others starved. Good fitting bearings mean that high oil pressure can be maintained and, it is imagined, a better equality of distribution with less susceptibility to variation with temperature. We have built up an engine with carefully fitted - hand scraped - bearings and at 1000 r.p.m. we obtain an oil flow of only .8 pts/min. at 34.5 lbs/sq.in. pressure. contd :- | ||