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).
The condition of main and big end bearings and the results of testing alloy cast iron crankshafts in oil engines.
| Identifier | ExFiles\Box 132\1\ scan0022 | |
| Date | 18th April 1927 guessed | |
| - 9 - amount of wear on the crankpin journals is negligible. Main bearings. The main bearings were in excellent condition. Big End Bearings. The R.R.56 big end bearings appeared to be in perfect condition. Approximate sizes of these bearings are as follows:- No.1 No. 2 No. 3 No. 4. +.0025 +.0025 +.003 +.00175 The amount of wear on the R.R.56 is of a negligible order, and it is of interest to note that on conclusion of the test the average running clearance of these bearings is .003". The total mileage which the engine covered during the 2 1/2 years' service cannot be accurately ascertained, but is estimated at approximately 40,000 miles. CRANKSHAFTS FOR USE IN OIL ENGINES. The encouraging results from every test to which the particular alloy cast iron crankshafts so far had been submitted, gave some measure of confidence that success might attend their use in compression-ignition oil engines. To this end two six-cylinder oil engine cast crankshafts were fitted into service engines which were eventually run in passenger vehicles. The results were quite definite for both crankshafts broke after a short service of three weeks. In one shaft failure occurred in the web adjacent to the centre main bearing, and in the other fracture took place adjacent to the throws on the No. 4 and No. 5 cylinders, and there was also a piece of metal broken out of the flywheel mounting flange. These failures of cast iron crankshafts in direct compression ignition engines gave rise to further consideration | ||