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).
Modifications to piston rings to improve oil consumption on certain models.
| Identifier | ExFiles\Box 144\3\ scan0099 | |
| Date | 10th August 1936 guessed | |
| -2- Ha/Rm.{William Robotham - Chief Engineer}1/MJ.H.S.30.Cont'd.{John DeLooze - Company Secretary} section piston rings. This is the standard ring with a piece turned out at the back to make it 'L' shaped as in the attached sketch. These rings were fitted on production and gave satisfaction. They are still being used on replacement work. The Repair Dept. state that they have given satisfactory results in service. We find that if we take the middle ring on the present standard 20/25 piston and by turning a portion off the back make it into an 'L' shaped ring, we improve the oil consumption by approximately 300 M.P.G. This oil consumption is effective as soon as the rings are put into the engine. They do not require any bedding in. It means that cars at present being delivered to customers which are giving 300 M.P.G. will now do 600 M.P.G. We are proposing to send some of these rings out to 22-GY. in France so that we can get some Continental endurance running on them. The difficulty in this case is that the cylinder bores will have worn considerably since the engine has already done 13,000 miles and therefore we shall have to fit a new cylinder block to get a reasonable figure of merit for the ring. In the meantime we are carrying out endurance running on the test bench and on the road in Derby. We recommend that this modification should be carried out immediately to all cars now in the Test Dept. at Derby and all 45/30's subsequently built with the unpinned rings and that 'L' shaped rings should be supplied to Cricklewood to be fitted to customers who are at present having trouble with overoiling. We understand that there are about six serious cases at present. It is necessary to point out that we are forced into the position of having to recommend this emergency measure because of trouble in customers hands which could not have been foreseen from the running on this car which has so far taken place in France. This investigation may be of assistance in case of trouble with the Phantom III. Ha/Rm.{William Robotham - Chief Engineer} Attached: Print. | ||