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).
Typed letter detailing investigation work on high petrol consumption, lubrication, and 'webbling' on a 20-HP car.
| Identifier | ExFiles\Box 5a\2\ 02-page042 | |
| Date | 21th January 1929 | |
| X58400c To: E.W. From: C.W.H. Hôtel de France, Châteauroux, Indre. January 21st. 1929. We have received your letter of the 19th. and note you are sending a new piston and rings. We have to-day been carrying out investigation work on the 20-HP and can tell you definitely one reason for the high petrol consumption is the engine has been run with a low water temperature to avoid pre-ignitions, that is round about 70°. I have been out this afternoon and found that I could weaken the high speed jet 5 notches when running with the water temperature 85°. As we reported, the carburation is very much affected by the water temperature. Before we can carry the consumption tests to any extent, we must have the new piston. The central lubrication has and is receiving full attention. We cannot understand your attitude re the lubrication of propeller shafts, as they have run easily 5,000 miles and been well lubricated. The ones you mention that ran 15,000 miles I examined personally and would not agree that the condition was any too good. I remember perfectly that there was not any loose oil left in the joints. there was certainly a film of oil on the joints. Surely we do not expect to run a car up to a condition of that kind. I distinctly put in my report the quantity of oil that the mechanic joints held when absolutely fail, and the amount that had to be added. we should consider very little for 5,000 miles. We dismantled the mechanic joints on the S.S. and the condition was exceedingly good, and oil poured out when the joints were broken. We can say with every confidence that if all mechanic joints are made as good as the ones we have run, there need be no fear of them not being lubricated at the end of 5,000 miles. The central lubrication we have worked upon and have given you as much information as we have found out. We very definitely say that the valves in the Bijur drip plugs do not maintain a line full of oil, therefore in our report we have said it would be advisable to give two charges of the pump every 200 miles with a view that the first charge would fill more or less the pipe lines, the other charge then would be definitely oiling the different units. Are you satisfied with the method of reporting on the S.S. bijur system, is it clear enough? Re the webbling on the front of the 20-HP we will endeavour to investigate this as soon as we can. During this afternoon's run, I have found that the engine on the 20-HP is too free on the rear engine rubber mountings, which causes the back end of the engine to jump up and down or wobble about. This may or may not have an effect on the webbling of the front of the car. In any case instructions have been given to examine the rear rubber anchorages. You may take it for granted that the fullest investigation work will be carried out as soon as we have finished with the S.S. The S.S. has been a big job to tackle over here. Every part has been thoroughly examined. We have gone so far as to repair and make good the mud-guards on the rear brakes, as we saw that these could not be taken | ||