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).
Issues with sticking Phantom oil pressure relief valves and proposed solutions.
| Identifier | WestWitteringFiles\O\January1926-March1926\ Scan132 | |
| Date | 13th March 1926 | |
| TO R.{Sir Henry Royce} FROM E.{Mr Elliott - Chief Engineer} Copy to - CJ. " HS.{Lord Ernest Hives - Chair} " HY.{Tom Haldenby - Plant Engineer} ORIGINAL PHANTOM OIL PRESSURE RELIEF VALVES. With regard to the question of sticking relief valves HS.{Lord Ernest Hives - Chair} agrees with us that the trouble is probably due to very small pieces of dirt wedging between the valve stem and the guide when the valve tries to close. Unfortunately in the case of the 20HP. and the high pressure Phantom relief valve the stems do not over-run the guide surfaces and the slightly chamfered leading edges of the fluted stems may entrap dirt. We therefore propose counterboring or undercutting the guides as shewn in red ink on E50303 and LeC. 1953. attached. With regard to finding a cleaner and more accessible place for the Phantom relief valve unit we attach a print of LeC. 2214. shewing the unit attached to the upper half of the crankchamber immediately behind and below the carburetter, but above the side guard. In this situation the oil discharge takes place via a passageway drilled in the upper half of crankchamber as shewn exactly halfway between cyls. 4 and 5. We do not think there will be any tendency for this oil to be picked up by the crankshaft, seeing that the general direction of motion is downwards, but if so, then a simple sheet metal channel fixed to the inside of the lower half should prevent it. We regret that this position for the unit adds to length of the relief passageway on the pressure side of the pump, but we can if it be found necessary fit a larger pipe to decrease the resistance, or we could add to the resistance on the suction side of the oil pump. Whatever type of relief valve is finally used the position of the unit is a separate question, and if therefore you approve of the scheme in this respect we should like to alter the crankcase patterns as soon as possible. As regards the valves, the high and intermediate pressure are of the same pattern as those shewn on the schemes for the 20HP. which we sent to you, except that they are larger. The low pressure valve as per your original instructions for this scheme is one having a guide, but the type we have shewn is most unlikely to stick, and even so loss of pressure in this section would only be a trivial matter. E.{Mr Elliott - Chief Engineer} | ||