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).
Endurance tests of whitemetal main journal bearings following modifications to the lubrication system.
| Identifier | ExFiles\Box 114\2\ scan0230 | |
| Date | 27th November 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/Swd1.14/KW.27.11.35. The whitemetal main journal bearings which ran throughout these endurance tests, making a total of 33 hours, were in excellent condition. These comparisons were taken with a modified lubrication system to E/JRR.1/MP.21.8.35., which includes the following - (1) Oil passage way through the bearing cap dowel pins increased by drilling away the thread to .161" dia. (2) An extra hole .250" dia. and at 180° to the existing hole in each crankshaft journal. (3) All the big ends and main bearings grooved. We cannot say that this modification has effected any improvement, as on the original system a total of 105 hours was run before a big end failure, including a 1 hour run at 4,500 R.P.M. and 25 hours endurance at 4,000 R.P.M. The increased hole in the dowel pin feed and the extra hole in each Crank Journal, together with the grooving of the intermediate main bearings, must be an advantage to the lubrication of the big ends. It is doubtful whether the grooved big ends are any improvement as they might possibly weaken the resistance of the bearings against the loading imposed. We think it is worth trying once more deleting the grooves and making up the lubrication by having 3 holes instead of 2 in the crankpins and close clearance lead bronze bearings, at the same time increasing the oil pressure to about 40 lbs/sq.in. Our next run will be under these conditions. The comparative endurance tests were carried out with a pressure of 25 lbs/sq.in. with an oil inlet temperature of 100°C, and outlet of 124°C. Summarising the results, the Marine rod in conjunction with its big end bearing is definitely a better proposition than the Strap rod, but even so the performance of the big end is as yet by no means satisfactory. Hs{Lord Ernest Hives - Chair}/L.H.Swindell. | ||