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).
6,000-mile report on engine 18.9-IV, detailing performance issues and component conditions.
| Identifier | ExFiles\Box 5a\2\ 02-page340 | |
| Date | 18th December 1930 | |
| Hs.{Lord Ernest Hives - Chair} R5840. To: Hs{Lord Ernest Hives - Chair} From G.W.H. Hotel de France, Chateauroux Indre. 18/12/30. REPORT ON 18.9-IV. at 6,000 MILES. ENGINE UNIT "C" 7 The engine generally has been good for power and acceleration, slow running became erratic after 1200 miles due to the exhaust valves having lost the tappet clearance. It has been free from any marked detonation. Cleanliness of the engine is not particularly good. There is a bad oil leak from the rocker cover which drains down the outside of the cylinders. There is also a leak of oil from the anulus of the fan drive pulley which is caused by too high a crankcase pressure at high speeds. This is a recurrent complaint on all 10,000 miles tests. The lay out of the suction pipe to the autovac and the petrol feed pipe from the autovac requires altering. The position of the bottom feed pipe from the central lubrication pump O.S. makes the removal of the rocker cover difficult. This fitting would be neater and a cleaner job if it were placed at the rear instead of the front. CYLINDER HEAD The cylinder head was dismantled to ascertain the reason of the valve clearance decreasing during the day's mileages. We found that the exhaust valves had hammered into the seats considerably, a definite fringe having been made at the bottom of the seating due to the hammering. It would appear to be due to the cylinder head being of too soft a material. We should strongly advise tests to be taken on cylinder heads in production to prevent this failure. There has been no sign of any water leaks from the cylinder head. VALVES & FITTINGS to LOR. E.55577. E.56050 Valve Stem Packings } To suit Gland E.56051 " Spring Washers } Mod. Scheme 1253. E.53168 Exhaust Valves (S/SLV). E.55606 Inlet Valves (3 1/2% N.S.) E.55572 Valve Springs (Closed end type). The Exhaust Valves have deteriorated somewhat due to the failure of the seats. The bottom portion of the valve seating has been rounded off with the hammering effect. The Inlet Valves do not show this feature and are in a good condition. The valve springs are in a good condition and have been very quiet in operation. The asbestos gland packings show no sign of deterioration and no overoiling has taken place through excess oil passing down the valve guides. The valve stems and valve guides are in a good condition and have been amply lubricated. | ||