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).
Technical memo discussing the investigation of low oil pressure on Chassis B.26.JD (Dreyfus).
| Identifier | ExFiles\Box 146\2\ scan0139 | |
| Date | 18th March 1937 | |
| W/P. - Sr. from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. to Mx.{John H Maddocks - Chief Proving Officer} 1245- Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}13/R.18.3.37. CHASSIS B.26.JD.{J. Draper - Frames} (Dreyfus). In reference to your memo Sr/VA7/ET.16.3.37., we note that you did not remove the large capacity oil pump from the above car as you suggested you were going to do, in an earlier memo. This chassis should, therefore, have the increased capacity pump as originally fitted in the Works, and can be verified by the external dimensions of the case housing the gears. This should be 1 1/2 against standard pump figure of 1 1/4. Assuming you have checked everything over that could have any bearing on the oil pressure, such as:- (a) Relief Valve perfectly free with a good seating. (b) " " spring standard. (c) No leaks on the suction side of the pump, and clean sump filter, then it is difficult to guess the reason for the low pressure on this car. The fact that there are several adjusting washers already under the Relief Valve would indicate that there is excessive bearing leak, and would recommend that you drop the lower half and take a pressure test of the bearings to see if the flow from them is uniform and not excessive as judged by your experience when correcting "sinkage". Whilst the sump is down, the cap half of the bearings can be checked over for signs of seizure as we have found that partial seizures do cause pressure drop at high oil temperatures. We presume that you are running on Castrol and not Mobiloil Arctic, as the latter would accentuate low pressure. The above to be carried out if the opportunity occurs, and you cannot find any reason for the big drop in pressure. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||