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).
Letter describing a heavy thud or knock in an engine, particularly when pulling hard, and requesting an in-person inspection in Derby.
| Identifier | WestWitteringFiles\E\September1920\ Scan28 | |
| Date | 11th January 1924 | |
| long time ago. I am told this engine had a bad revolution knock when running light. I have noticed that it is a very heavy thud, but not so much felt throughout. It appears to be a thud, especially when pulling hard. It is a long, but not a heavy thud, when the engine is running at about 1,000 engine revs. When pulling hard, it has to be a longitudinal movement of the crankshaft, but I feel it is a mechanical main bearing which has worn to a given way. The main bearing which has worn to the extent that it required to be taken up, with the threads worn right off. These cases were sent back to you, and I kept the ones which were on at the time she arrived with it. This is a good hammering at the engine, not a loose component. This thud is previous to the one she had. I do not know what this thud is, but I should be pleased if you would endeavour to come to Derby some time soon when you are not at all busy, it would be advisable for you to see me. As this thud is of the nature that it is susceptible to the pressure and is felt by the passengers as well as the driver. Mr. H.{Arthur M. Hanbury - Head Complaints} would know if so. | ||