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).
Design considerations for an engine's oil pump drive, valve operation, and cylinder heads.
| Identifier | ExFiles\Box 111\2\ scan0220 | |
| Date | 18th August 1937 | |
| -3- OIL PUMP DRIVE (11) Arrange so that there will be no necessity for a cast sump unless this is desired for other considerations. (Considerable wt. saving and cost). Internal pump with suction below oil level. To reduce audible noise and loss of pressure through 'swilling'. VALVE OPERATION (12) As a 'safety first' policy it was agreed that we should have Phoenix unit available as a straight push rod operated unit. It was considered that the lay-out of this could follow Wraith closely. In parallel with this engine unit it was agreed that the overhead inlet side valve exhaust super-structure should be grafted on the same base, if this was at all feasible. The suggestion was that the designs of both engines should proceed in parallel, and that the drawings for both should be sent to the Pattern Shop simultaneously so that the cylinder block pattern should be made convertible to either design. We should like sufficient room to be left so that hydraulic tappets of the direct acting type, as fitted to the Cadillac, Lincoln Zephyr, etc. etc. could be introduced at some future date if this was found to be desireable. We have in mind that a long toe camshaft with a big inlet valve on the high power head may spoil the idling. Also that it may be difficult to get the valve gear quiet with this big valve unless hydraulic lash adjusters are used. CYLINDER HEADS (13) We have found 4-port cylinder heads to be easiest to handle from a distribution and carburation point of view; on the other hand, the Americans have had complete success with 3-port systems on 6-cylinder engines, and we shall shortly have an opportunity of testing the Vauxhall on the bench. We have recently come to the conclusion that a distinct advantage could be obtained by separating the exhaust from the front and rear three cylinders, at any rate for an appreciable time after it leaves the port. We know it is difficult to get a 4 port inlet and 4 port exhaust system on a push rod head, and for this reason we do not want to make a final decision yet as to whether we use a 4-port or 3-port induction system. On the high power head it would appear that we could, with continued | ||