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).
Crankcase depression tests comparing a 25.HP model with a Chevrolet.
| Identifier | ExFiles\Box 103\2\ scan0277 | |
| Date | 5th February 1937 | |
| To Rm.{William Robotham - Chief Engineer} c. to Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} γ .576. 5.2.37. CRANKCASE DEPRESSION TESTS. We have completed tests to show the difference in the crankcase depression between the 25.HP. and the Chevrolet. On the Chevrolet two gauges were used, one from a union placed in the highest point possible in the crankcase lower half, and the other from the hole which carries the dip stick. The readings obtained at the various car speeds were not sufficiently consistent to justify recording them, but it was noticed that while there was a slight pressure .400" of water with the car standing, this levelled out and changed to a depression, which never exceeded .600" of water with the car moving at varying speeds. Under ordinary running conditions the gauge showed the crankcase to be at atmospheric pressure, with a tendency to record a slight depression. 22.G.V. A pipe was let into the oil filler and projected about two inches into the crankcase. On this car a maximum depression of .300" of water was attained, and was dependent on engine revs. There was no pressure standing, as on the Chevrolet. The test was repeated with the vent from the rocker cover to air silencer blocked up, but the result was the same. At normal touring speeds the gauge remained steady at atmospheric pressure. Rm{William Robotham - Chief Engineer}/W.Brazier. | ||