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).
Typed letter responding to a telegram regarding a low oil pressure issue on model B.35.KU.
| Identifier | ExFiles\Box 114\3\ scan0166 | |
| Date | 5th November 1937 | |
| Sr. KINGSBURY. Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux}/DPB.5.11.37. re: B.35.KU. LOW OIL PRESSURE I have received your telegram and replied as follows:- (1) Check release valve for sticking. The reason I sent this reply is because we have had the same trouble here and have found that the ball valve was not seating correctly and a slight tap on the ball in position with a brass drift corrected the seating and made the oil pressure normal. (2) Check bearings of engine for oil flow. The reason for this is, your reply release valve O.K. I assumed the above had been carried out, therefore the drop in oil pressure can only be due to sinkage of the bearings allowing excessive oil release from them. The drop to 12lbs hot is surprising for the short mileage and I can only assume that the bearings have been fitted with the maximum limits, which have since been tightened up. These limits allowed the shells to be slack in the housing with the .005" nip which the Works used to allow. If you can take an oil flow through the bearings, the following will be a guide but is not as yet definitely established. Engine turned by hand approx. 50.r.p.m. C.W. Oil used for test. 30° C temp. Engine allowed to cool down to 30° C temp. (not water) (thermometer in filler of base). Time to pass one gallon of oil at 30lbs pressure 30 min. 38 min. Bottom filter taken out to drain sump and catch oil, pipe connected to main feed pipe in crankcase, disconnected from pump. I have given you these particulars but the safest thing to do is to remove the engine and check the bearings for slackness in the housings, main and con.rods. ---------------- You are aware i tested your chassis on Brooklands. -contd- | ||