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).
Engine endurance run detailing oil consumption, a crankcase crack, and S.U. carburetter washer failure.
| Identifier | ExFiles\Box 86\2\ scan0101 | |
| Date | 25th October 1933 guessed | |
| -4- The oil consumption measured over a period of 17½ hrs. was 10 pints, which assuming an average speed of 85 m.p.h. gives an oil consumption of 1200 m.p.g. This consumption is exceptionally good when considering the fact that the oil pressure was maintained at 70 - 80 lbs/sq.in. with the temperature at anything up to 90ºC inlet temperature. The endurance run also brought to notice one or two weaknesses we had not realised before. After 17 hrs. running a crack appeared in the crankcase top half on the off-side immediately above the flange connecting the top and lower halves and by the centre bolt. This is shewn in diagram 3. After 14 hrs. running the fibre washers above and below the joint of the floatchambers and the throttle bodies of the S.U. carburetters failed and leaked petrol very badly. These washers were replaced by aluminium washers and no further trouble was experienced. This joint is a poor feature of the S.U. carburetter in that there is always a tendency, on the test bed at any rate, to work loose. The joint has always to be tightened up exceptionally hard and when the fibre has been in use some time and become brittle, the washers always crack and have to be replaced. We ought to mention that the brinell hardness no. of the pistons before running was 114. Attached are sketches and chart of dimensions of Aerolite pistons before running (BV.7/8/9/10). Hs{Lord Ernest Hives - Chair}/R.Matthews. | ||