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 comparing oil consumption and pressure between the Silver Ghost and Phantom models, attributing differences to bearing clearances.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan105 | |
| Date | 1st May 1926 guessed | |
| contd :- -3- the one case. If however we plot these consumptions on an oil pressure base we immediately notice a marked difference between the two curves - as shown here. For the Silver Ghost a higher pressure has to be used than the Phantom in order to obtain the same consumption, therefore it is reasonable to attribute this to a difference in the bearing clearances. [Graph] OIL CONSUMPTION & PRESSURE. --------- CARS.EX. SILVER GHOST. --------- CAR 10.EX. PHANTOM. Y-AXIS: CONSUMPTION - MILES/GALL. X-AXIS: OIL PRESSURE. lbs/□". From these curves one would estimate that the Phantom had roughly 50% to 60% greater bearing clearance than the Silver Ghost, assuming the discharge to be proportional to the square root of the pressure. It should be mentioned that the above two cars are fairly representative of the respective models. The Phantom has reamed bearings - no hand fitting. AVERAGE OIL FLOWS. We find in practice that the average oil flow from a Phantom is considerably greater than a Silver Ghost. Also on the Phantom considerable variation in flow from car to car is experienced. Reverting to the Silver Ghost practice of three main feeds has proved to be a definite advantage when the initial [text struck through] contd :- | ||