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).
Investigation into 'engine thuds' on the Phantom engine compared to the Silver Ghost.
| Identifier | ExFiles\Box 65\4\ scan0336 | |
| Date | 1st May 1926 | |
| To B.J. from Hs.{Lord Ernest Hives - Chair} c. to CWB. c. to H.{Arthur M. Hanbury - Head Complaints} X 8050 Hs{Lord Ernest Hives - Chair}3/LGS.5.26. ENGINE THUDS. (EJS/EG.5.26.X417) For some time now we have asked the Production Test Dept. to let us have an opportunity of investigating a Phantom engine which is complained of. Quite a considerable amount of investigation has been made already and as far as we have gone it would appear that the characteristics of the thud on the Phantom is very different to the very frequent thud we got on the Silver Ghost engine. In the case of the Silver Ghost the thud always occurred on No.6 cylinder, it was always worse if the engine ran on the intermediate plugs instead of the plugs in the pockets. It was worse under full load conditions. We carried out a lot of investigations on the Silver Ghost and our views were that the crankshaft formed an excellent spring drive. One can easily imagine that the impulses of No.1 cylinder transmitted the whole length of the crankshaft passes through a very efficient spring drive, whereas the kick from No.6 cylinder which is solid with the flywheel would produce a different effect. Thuds from No.6 cylinder occur on other makes of car. The Napier people arranged that the compression on No.6 cylinder was lower than the others. It will immediately be pointed out that there are some cars which are entirely free from this complaint. We think the reason for this is that although the cause is there, the effect is not shewn up owing to variation in fits and clearances. We believe that investigating the complaint on the Silver Ghost would not help us very much with regard to the Phantom. We think the investigation should be carried out on a Phantom and this we are anxious to do as soon as an example of the complaint can be brought to us. Hs.{Lord Ernest Hives - Chair} | ||