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 vibration issues on the 12-EX model.
| Identifier | ExFiles\Box 13\7\ 07-page006 | |
| Date | 1st October 1926 | |
| To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. BY.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} CWB. c. to PN.{Mr Northey} 47300. RL/M1.10.26. 12-EX - VIBRATION ETC. X.634 X.8010 EX.7010 X.7300 With reference to 12-EX which came to WW. on the 29th.ult. this car appeared to be in good condition after its 10,000 miles, but still shewed the same vibration reported to be due to the more rigid cast dash. I do not believe that the cast dash could make such a marked difference, and that it is something out of balance on the engine proper. My first suspicion would be the clutch and flywheel, then possibly the pistons, or the coupling. I have suggested this should be analysed, one way being to change the pistons, weighing those which are removed, to see that they are equal to each other in weight, then fit the lightest pistons we can muster. Should this make no difference we should recommend that the flywheel and clutch be first tested for running truth, and then removed and tested for running balance. Anything that can be done to render the whole engine more accurately balanced would I am sure pay. It is a vital and sensitive point, and one often hears of the variation of one engine from another in some respects, which I personally believe is due to the variation in balance. I do not think the above vibration is anything to do with the crankshaft period, as it seems to follow the engine from low to high speeds. It was noticed that the shock dampers rendered the car very steady on the road. We presume that the relief pressures chosen are about right. I could not find any disadvantage with the steering except that it was slightly heavy when the car was standing, owing to the big tyres on our gravelled entrance. Regarding the change gear the levers fouled one another, but we presume that this has been temporarily bent. Regarding the direct drive in the box I understand this still has the old coarse jaw. Fourteen months ago we were pressing for these to be changed to the gear tooth type. We believe these are fitted to RAC.1. and 7. R.{Sir Henry Royce} | ||