Performance and issues of valves and fittings during mileage testing, including modifications and component failures.
| Identifier | ExFiles\Box 101\2\ scan0043 | |
| Date | 20th July 1936 guessed | |
| ( 3 ) VALVES & FITTINGS. LOP E.60760 Complete to above LOP incorporating:- 3 Ex.22459 Exhaust Valves No 1.3.5. 1.225" dia.seat. tulip neck to LEC 4915 Stellite seats. 3 Ex.22460 Exhaust Valves No 2.4.6. 1.225" dia.seat. Bentley Type Valves. Stellite seats. 6. E.60892 Inlet Valves S/SLV.increased valve seat dia. to suit existing heads. 6. E.61012 Top Washers. 6. E.61013 Bottom Washers. 6. E.61013 Wedges. LEC 4979 Mod.to rocker arm & shaft oil drilling. E.2854 Rocker Shaft. EB.2588 Rocker arm } Incorporating alt.18065/E inclination EB.2589 Rocker arm } of .125" dia.hole altered from 80 to 50 The rocker gears & valves have been reasonably quiet. The lubrication has been ample with the oil pressure remaining good. These exhaust valves had been fitted temporarily and were removed after running 4.100 miles. They were in good condition and there has been no loss of tappet clearance. Maximum speed had not been used owing to valve bounce with the weaker valve springs. At 13.270 miles, the following new parts were fitted as ordered for standard production:- 6. E.61073 Exhaust Valves 6. EB.1747 Retaining Rings 6. EB.1783 Bottom Washers 12. EB.175 Valve Springs. 6. EB.2792 Top Washers. 6. EB.1748 Wedges. 6. EB.1784 Packings. With these valves & springs fitted, there was no valve bounce throughout the range, and the car was run up to maximum speed. The new exhaust valves ran for 6.000 miles without any loss of tappet clearance. During the following 1.500 miles, the loss of the clearance on the exhaust tappets was 2-5-1-3-2-5 thous. reading from engine front. No further loss occurred during the final 2.200 miles running. No 4 cylinder exhaust valve stuck open after 8.850 miles running and it was necessary to release it with a lever before we could proceed. After 9.500 miles, the same thing occurred to the exhaust valve of No 1 cylinder. Examination revealed that the stems had picked up badly, and that the valve guides were marked about one third of the way up. The other exhaust valves also showed signs of sticking. They were all quite free in the guides cold and the trouble would seem to be due to overheating of the valves. The seats were somewhat burnt and there was a deposit of carbon and lead on the valves. The loss of clearance is more likely to be due to pocketing than to valves stretching. The valve seatings indicated this but careful measurements are required to verify it. Oil leaks were experienced from the rocker cover joint. They were found to be due to the knurled fixing nuts screwing down solid before sufficient pressure was applied to the cork joint. This should receive the attention of the D {John DeLooze - Company Secretary} /O. | ||
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).