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 failure of an oil relay ignition advance scheme due to a perished cup leather.
| Identifier | ExFiles\Box 71\4\ scan0101 | |
| Date | 3rd March 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. K8940 Expl. No. REF Hs{Lord Ernest Hives - Chair}2/L.031.3.25. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RO.{C. C. Rose - Export Manager} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to Wor.{Arthur Wormald - General Works Manager} S E C R E T. EAC. - OIL IGNITION RELAY. K8685 The oil relay ignition advance scheme was not working correctly when 98-NK car returned after the 10,000 miles test in France. On examination this was found to be due to the cup leather having become charred and perished. We have had this failure on the test bed engines. On there, we cool the main pressure oil which goes to the engine bearings. We have not however cooled the oil which goes to the oil relay. The maximum temperature we have measured of the oil to the relay reaches 85°C after continuous running. We did not anticipate we should have this trouble with the cup leathers on the road, owing to the oil keeping cooler. All engines will be fitted with chrome cup leathers which the makers say will be satisfactory up to 85°C. It might however be considered advisable to proceed with an alternative scheme of having piston rings in place of the cup leather. It is possible that the oil will run hotter on the EAC. compared with the standard 40/50 owing to a considerable portion of the cylinders being inside the crankcase. Hs.{Lord Ernest Hives - Chair} | ||