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).
Comparison of Rover engine bearing lubrication and materials against Bentley practice, with proposed improvements.
| Identifier | ExFiles\Box 116\1\ scan0130 | |
| Date | 30th August 1937 | |
| -2- 30.8.37. From the figures supplied to use by the Rover Co., we find that the oil pump capacity should be quite adequate for the job, and is, approximately the size we use. The flow through the bearings, however, on the Rover engine is much less than we should recommend, approx. only 10% of the circulating oil is passed through the bearings, whereas we pass between 30% and 40% of our oil through the bearings. From the figures below it is evident that the oil grooves are restricting the flow considerably and comparison is drawn with Bentley practice. BENTLEY. PRESENT ROVER. PROPOSED ROVER. Feed hole to main bearings .0191 " .090 " .090 " Area of oil groove in main bearing. .0175 " .007750 " .015 " Area of feed holes in crankpin. .00245 " .049 " .00294 " Flow through bearings. 104 galls/hr 10.7 Gall/hrs The present feed to the crankpin we think can be improved by adopting the method shown in sketch. In the existing practice the bearing is sealed off from the oil supply at position of maximum cylinder loads due to the pressure of the bearing on the crankpin. We, therefore, suggest that it would be better to have two small holes drilled on an axis at right angles to the existing hole. We have run this metal in conjunction with a shaft having a Brinell hardness of, approx. 320, but have had no experience with a shaft as soft as that used by Rover's, the Brinell of which is 265-270. We do not say that the metal is not satisfactory with such a soft shaft, but that it may be better if the Brinell is increased to approx. 320 - 340. We would also suggest that the bearing is prevented from rotating by use of liners (in R.R. 56 material), and that the bearing material stands proud of the rod and cap to the extent of .0005 to .001, so that the bearing is definitely 'nipped' when assembled. Apart from these items, there does not appear to be any reason at the moment why the bearings should not be satisfactory, and with the modifications suggested we think the performance will be improved considerably. Hm{Capt. W. Hallam - Head Repairs}/R.{Sir Henry Royce} Matthews. | ||