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).
Comparison of engine oil flow and pressure between Silver Ghost and Phantom models, detailing methods for reduction.
| Identifier | Morton\M18\ img084 | |
| Date | 26th June 1925 guessed | |
| contd :- -4- feeds has proved to be a definite advantage than on the [unclear] oil flow is excessive. The average Silver Ghost with 20 lbs/sq.in. oil pressure at 1000 r.p.m. gives an oil flow of about .9 to .95 pts/min. while the Phantom with its normal oil pressure of up to 30 lbs/sq.in. gives from 1.5 to 3.0 pts/min. and in a [unclear] bad case on a warm engine we have observed as much as 11 pts/min. METHODS OF REDUCING OILFLOW. The two methods of reducing the oil flow on the Phantom (so that it is similar to the Silver Ghost) which suggest them- selves are :- (1) Reduced oil pressure - and (2) Reduced bearing clearances. We have tried both methods and while the required 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 impracticable and would leave open to chance some bearings receiving all the oil while others starved. Good fitting bearings mean that the oil pressure can be maintained and, it is imagined, a better equality of distrib- ution 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 24.5 lbs/sq.in. pressure. contd :- | ||