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).
Engine performance issues such as over-oiling, noise, and vibration during road testing.
| Identifier | Morton\M2.4\ img002 | |
| Date | 23th July 1920 | |
| Contd. -2- the Magneto. The water is delivered to one end of the cylinder block only - there are three outlets at the top. We have not had the cylinders off but from examination we have seen that aluminium pistons are fitted. There are no distinct piston knocks. The engine over-oils when run light and smokes badly when accelerated. The valve operating gear on the engine is very noisy. This is in spite of the tappets being set at .001" to .002" clearance. There is a very bad period on the engine at 67 M.P.H. on top gear - 43 M.P.H. on 3rd. gear - 28 M.P.H. on 2nd. gear. It is a particularly bad vibration and is equally as bad on retard as it is under load. As we can only just get over 60 M.P.H. on the level with stripped chassis, one never reaches the period on top gear; it was necessary to race up on the gears to notice it. Apart from this one period the engine was quite good. It is very good indeed for absence of picking up vibration but this we think might mostly be due to the fact that it is impossible to open up full power at low speeds because if the accelerator is fully depressed when the engine is running slowly the engine stops owing to weakness. In getting away one has to use the throttle very gently. On top gear the minimum slow running without it missing fire was about 10 M.P.H. The lift of the inlet and exhaust valve is .375. Below is the HP. obtained on the dynamometer:- Contd. | ||