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).
The performance of a 'General' filter regarding oil sludge accumulation and cartridge renewal mileage.
| Identifier | ExFiles\Box 97\5\ scan0217 | |
| Date | 9th June 1939 | |
| -2- The amount of sludge which settled out of the samples drawn off did not increase as the mileage progressed. The oil appeared more or less dirty according to the mileage run over 5,000 on each cartridge. The new cartridge would clean the oil in 800-1000 miles and maintain a clean appearance for 5,000 miles. We recommend this as the mileage at which the cartridge should be renewed in service. The rocker gear, crankcase walls etc., remained cleaner than usual with very little sludge adhering to them. The crankpins and slipper wheel had, however, collected considerable quantities of sludge. In conclusion, we find that under the conditions run the "General" filter is effective in preventing an accumulation of sludge in the sump and on the rocker gear etc. and in maintaining the oil in a clean-looking condition, if the cartridge is renewed every 5,000 miles. We also find that at the rate of replenishment stated, the oil will retain its lubrication properties over periods in excess of 52,000 miles. When we consider that less than .016 pints of the original oil remained after this mileage, we see no reason why it should required changing between engine overhauls, always provided that sediment does not accumulate or acidity and dilution increase. The test shows that the "General" filter is capable of preventing the accumulation of sediment. The analyses are satisfactory as regards acidity and dilution, but these factors may be very different under traffic and town conditions. Tests are in progress on WXA.36 in London and the results are being analysed by the Vacuum Oil Co. which should show whether it is safe never to change the oil when using the "General" Bye-pass filter. RM{William Robotham - Chief Engineer}/IBW. | ||