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).
22.5-hour test of loose white metal lined connecting rod bearings.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan318 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: HS{Lord Ernest Hives - Chair}/AEM/1339.9.25. C E.A.C. CONNECTING ROD BEARINGS - LOOSE WHITE METAL LINED BUSHES. We have just completed a 22½ hrs. test of the new loose bush connecting rod bearings on the test bench and the results of this test show that these bearings are superior to the standard type. The conditions of the test were as follows :- Engine run at full load 3000 r.p.m. Temp. of oil supply to bearings 100°C. This is not the limiting temperature but it was maintained at this temp. by means of an oil cooler. Average pressure 15 lbs/sq.in. Oil used Prices Motorine 'C'. The bearings used were three with bronze white metal lined bushes (B Z/G WM/T) and three with mild steel white metal lined bushes. They were in excellent condition at the end of the test with the exception of nos. 1 and 2 which were both bronze bushes. The white metal of these had cracked and seemed to be entirely due to the con. rods of these two being out of line caused by crank-case expansion as shown by sketch and resulting in unequal pressure distribution on the bearing. We consider this expansion to be an extreme case and although we have no actual readings of the crankcase temp. it must have been abnormal when we consider that the oil temp. after passing through the cooler was 100°C. contd :- | ||