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).
Proposed alteration to the cylinder head for the Wraith III and Bentley III models to improve valve seat cooling.
| Identifier | ExFiles\Box 8\6\ 06-page53 | |
| Date | 11th May 1939 | |
| 679 H19 BY/NS{Norman Scott} c. NS{Norman Scott} c. BY/SH. c. RM{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. REC/VS.{J. Vickers} Instructed S & C to not detail Pales See me Rm{William Robotham - Chief Engineer} DA.{Bernard Day - Chassis Design}1/G.11.5.39. WRAITH III. and BENTLEY III. CYLINDER HEAD. Please receive herewith :- E.CD.1335 Proposed alteration to Cylinder Head to improve Valve Seat Cooling - Wraith III and B.III. In all our recent cylinder heads, we have endeavoured to make the water space around the combustion head as free as possible with a view not only to allow freedom of flow for the water, but also to facilitate the moulding in the Foundry, by avoiding very weak sections for the sand. Since introducing these improved water ways we have also suffered more from exhaust valve seat sinkage, and it is suggested that the cooling water now flows too freely along the cylinder head from back to front of engine, and is not being diverted across the head to give the necessary cooling of the valve seats, the proposal therefore shown on E.CD.1335 is to close the water passage somewhat along the side of the cylinder head to compel the water inwards towards the valve ports. This, of course, calls for pattern and core modifications to produce the new shape of head, but for test purposes, one or two heads should be produced from the standard pattern temporarily modified. We have made the new shape of jacket wall to give a compromise between obtaining a certain amount of deflection for the water in the head, and a not too bad condition for the sand core strength. Will you please detail and instruct for the experiment. This design was intended as an alternative to the experiment called for on E.CD.1349, of using coolant jets to obtain the necessary valve seat cooling, but in view of the success of the coolant jets it will probably be desired to use the two experiments in combination. However, E.CD.1335 may be used as a replacement head where it is not desired to fit the Jets. DA.{Bernard Day - Chassis Design} | ||