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).
Letter from Leyland Motors detailing the results of an engine bearing seizure test.
| Identifier | ExFiles\Box 116\3\ scan0051 | |
| Date | 2nd December 1937 | |
| LEYLAND MOTORS LIMITED, Head Office and Works, LEYLAND. LANCASHIRE. Manufacturers of Motor Vehicles ALL COMMUNICATIONS TO BE ADDRESSED TO THE COMPANY AND NOT TO INDIVIDUALS TELEGRAPHIC ADDRESS: LEYMOTORS, LEYLAND. TELEPHONE: LEYLAND 81400 (16 LINES) CUSTOMERS VEHICLES DRIVEN AT OWNERS RISK ONLY YOURS RM{William Robotham - Chief Engineer}/Mths{Reg Matthews}/2/MH{M. Huckerby} IN REPLY PLEASE QUOTE: OURS SM/ET Tel. Ext. 148 2nd December 19 37. Messrs.Rolls Royce Limited, DERBY. Dear Sirs, AC.6 BEARINGS. When your Mr.Matthews visited us a short time ago to inspect the AC.6 bearings after running on duration test, we advised him that after re-building the engine we proposed to carry out a test in which the oil supply to the bearings would be gradually reduced until seizure of a bearing occurred. This test has been fully carried out and we found that the oil pressure had to be reduced to zero before one of the big end bearings seized. On a subsequent examination it was discovered that the bearing which had seized was one of the RR.56 specially treated bearings, and that the seizure had been so severe as to turn the bearing shell inside the steel connecting rod. The remaining five bearings, consisting of two RR.56, and three AC.6 were found to be in quite good condition. From the results of this test it does appear that with either RR.56 or AC.6 bearings fitted at a running clearance of .0008" per inch of crankpin diameter that exceedingly severe treatment has to be given to the engine before anything serious happens to the bearings. We trust this information will be of some assistance to you, and if you yourselves have had any | ||