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).
Test report on engine bearing performance, detailing issues with lead sweat, distortion, and wear.
Identifier | ExFiles\Box 173\2\ img238 | |
Date | 23th February 1934 guessed | |
Page #2 pump was used to maintain the engine oil pressure at 70 lbs. per sq. in. The amount of boosting required of course increased with running speed of the engine. Somewhat more lead was sweated out of this bearing than on any of the previous tests of Allison bearings at the lower speeds. However, there was nothing to indicate that this bearing would not have a fairly long life under the load and speed conditions at 4250 R.P.M. Measurement of the bearing after test indicated considerable distortion of the crankshaft journal as the bearing was both tapered and out of round from .002" to .003". The pick-up of aluminum on the back of the steel shell was also appreciably greater than on the lower speed runs, indicating considerable working of the bearing in the case. Working of the bearing shell in the crankcase was appreciably greater in all tests than in the cap. Due to the pick-up on the bearing shells it was difficult to seat the bearing the same as during the run, therefore the clearances on the center main bearing as measured are not particularly accurate, a variation of over one thousandth inch in diameter could be obtained by re-seating the bearing. Test data is given on attached sheets. The journal wear on #4 crankshaft which was used on tests Nos. 2, 4, 5, 6, and 7 is also shown. On account of seizure of the Rolls Royce 'A' center bearing in Test #2 it was necessary to lap the center journal. The crankshaft measurements are therefore given for before Test #4 and after Test #7 and the wear for these tests is shown. Average wear of the main journals was .00033" for the four tests. | ||