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).
Vehicle performance issues including pre-ignition and a choked engine, with plans for further experiments.
| Identifier | ExFiles\Box 11\2\ 02-page047 | |
| Date | 7th January 1928 | |
| X52280 X7941 56 Hotel de France, Chateauroux, Indre. To: Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From: G.W.H. January 7th. 1928 We have received your letter Hs{Lord Ernest Hives - Chair}/RmA/1G.4/1/29. We have received the Lodge plugs and these have now run approx. 2000 miles. They are considerably better in respect of pre-igniting, but are not fully free from it. The engine is not any too good at anything over 3/4 throttle opening. We do not get the results expected for the last 1/4 opening of the throttle. This may be due to the long duration camshaft. The symptoms are the engine appears to be choked, pre-ignitions are evident, and probably the exhaust gas is not getting away free enough. We assume this, as we have no definite evidence while trying the car on road. The shock-dampers we have not altered in any way. The high tyre pressure that we are now running has steadied the car considerably, also with ballast in the rear has materially helped. Re the undershields, we agree that this is an interesting job, and we shall be pleased to carry out experiments providing the car is remaining here after the allotted mileage. We can easily get these made and try them out. At the present time, we are rather in the dark as to what is going to happen with the car. I expect Hs.{Lord Ernest Hives - Chair} will be arriving this week, then we may get to know something definite. As already reported to you, Allen, Whyman and Lytton left here for Derby yesterday. I let Lytton go because there did not appear to be anything for him to do for the next 10 days, and Hs.{Lord Ernest Hives - Chair} requested me to return men as soon as possible. I thought it was the best policy. If there are any big fitting jobs to do, he can be sent out again. Re the 20-HP now running, we shall examine the pistons immediately we have finished the mileage. From what we can observe, we should say that it is either the crown that has burnt or the rings gummed up. We shall let you have this information at the earliest possible moment. .G.W.H. | ||