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).
Tests to ascertain the value of a hole in the connecting rod for extra cylinder lubrication under cold starting conditions on a Bentley engine.
| Identifier | ExFiles\Box 141\2\ scan0242 | |
| Date | 10th February 1941 | |
| To: Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Hm.{Capt. W. Hallam - Head Repairs} c. Rm{William Robotham - Chief Engineer}/CRS. EXTRA CYLINDER LUBRICATION ON BENTLEY. 1184 Tests have been carried out on the rig engine to ascertain what value the hole in the conn. rod has on cylinder lubrication under cold starting conditions. Test No.1. Engine was placed in cold chamber to obtain oil temperature of 0°C. With cylinder head removed, engine was motored over by starter. Result:- No oil was thrown onto the cylinder bore, using either S.A.E.50 or S.A.E.20 oil. This being due to the engine turning too slowly. (approximately 150 R.P.M) Test No.2. Engine was rigged up to run on three cylinders under its own power. This was accomplished by cutting the cylinder head in half, leaving rear three cylinder bores exposed. A conn. rod with hole for extra cylinder lubrication was fitted to No.5 and one without hole to No.6 cylinders. To obtain a clear view of these two cylinder bores, a portion of the crown and skirt on the pistons were cut away. Engine was then started up and run at 750 R.P.M. with oil temperature at 0°C. Time was then taken from the moment the engine started until the first spots of oil had been thrown onto cylinder bore. The following times were obtained :- S.A.E. 20 OIL. NON-DRILLED ROD. | | Oil Thrown Onto Bottom of Bore. | Oil Thrown Onto Top of Bore. | |---|---|---| | Non Pressure Side | 4 Sec. | 8 Sec. | | Pressure Side. | 4 Sec. | No Oil after 60 Sec. | -Continued- | ||