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 and issues of various engine components after mileage testing.
| Identifier | ExFiles\Box 91\3\ scan0209 | |
| Date | 8th October 1935 guessed | |
| ( 4 ) VALVES & FITTINGS LOP E 86922 EXHAUST VALVES E 84829 UNDRILLED KE 965. INLET VALVES E 86783 S/SLV. We ran these valves up to a mileage of 6.456 after which, six KE SS{S. Smith} exhaust valves were fitted to the B Cylinder head and have ran 4.166 miles. The six KE 965 exhaust valves taken out were not in too good a condition. The seatings were pitted and had been attacked by the lead fuel. The Inlet Valve Seatings were good. We have not examined the KE SS{S. Smith} Valves at this mileage. DOUBLE VALVE SPRINGS LEC 4124. There has been no failure of the outer or inner Valves springs. We have had no indication of valves bouncing or springs being noticeably noisy in the front seats of the car. STRENGTHENED TYPE DURAL PUSH RODS. LEC 4626. We have had no failure during this test of push rods breaking. There is however a bad fouling of several rods at a point where they leave the Cylinder which in time would cause a fracture. CYLINDER HEAD E 86939 MODIFIED TO LEC 4702 TO IMPROVE FLOW OF OIL RETURNING TO CRANKCASE. The modification considerably reduced the quantity of oil on the Cylinder top and reduced the oil leak from the joint of the rocker cover. The modification is not sufficient to prevent oil being drawn down the inlet valve stems which caused a smoky exhaust whilst idling and when starting up, further modifications will be necessary. HYDRAULIC ADJUSTABLE TAPPETS LEC 4427. PLUNGERS E 85325 WITH .001 3 CLEARANCE BETWEEN CASE & PLUNGER E86880 SPRINGS GIVING A 5.3/4 LBS. LOAD FITTED UNDER PLUNGERS. ROCKERS 8 TO 1 RATIO. The Hydraulic Tappets have given trouble throughout the mileage. The chief cause has been shortage of oil feed to the plungers. There has been several causes for this shortage. The first noisy tappets came about after a hard sustained run. They would remain noisy whilst passing through a village at medium speeds, shortly afterwards becoming quiet. This was due to the feed not being sufficient. The escape of oil from the bearing of the rockers when hot starving the supply to the plungers. Secondly, the oil metering screws became choked up with fine hairs and fluff. Thirdly, foreign matter under the pump release valve, released too much oil [Handwritten text in left margin:] [Top] L.P. Smith Can we Improve on these [Middle] Outside oil leak on Rocker Cover [Bottom] Swell. What is minimum flow to rockers with oil at 130C. | ||