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).
Loss of oil pressure after braking and proposing modifications to the crankcase sump.
| Identifier | WestWitteringFiles\T\January1929-February1929\ Scan127 | |
| Date | 7th February 1929 | |
| R.{Sir Henry Royce} FROM E.{Mr Elliott - Chief Engineer} C. to SS.{S. Smith} HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} ORIGINAL E1/M7.2.29. X7010 X7000 X7090 X7420 LOSS OF OIL PRESSURE AFTER BRAKING. We suggest that an open bottom half crankcase should be taken, charged with oil, and be inclined forwards for various time periods corresponding to various degrees of braking. By this means the behaviour of the oil could be conveniently observed. To quote an example previously given an inclination of 1 in 2 for 5 secs. would correspond to a pull up from 60 MPH. in 240 ft. The liquid used should of course be of the same viscosity as hot oil. This test does not include the effect of the pump which will remove a pint of oil in 5 secs. with the engine doing 1000 RPM. We do not like the suggestion to face the suction port of the strainer casing forward because it would uncover too soon when hill climbing, and when braking it tends to empty the oil out of the strainer if the outer level has fallen. We cannot depend on having one and a quarter gals. in the sump to draw on when hill climbing owing to the amount of oil in suspension on the walls of the crankcase, valve gear chambers, etc, - about half a gallon. We rather feel we could increase the quantity of oil in the present sump. We think that in the recent tests shewing no loss of oil pressure except for very fierce braking oil musthave been lost over the tops of the cross webs, and we propose to raise the height of these webs as shewn on print of LeC. 2665. attached, which increase will hold back a considerable quantity of oil for braking of 50% and over. (1) | ||