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).
Modifications to the Peregrine Cylinder Head for finishing and economy purposes.
| Identifier | ExFiles\Box 2\3\ B002_X 116 117 119 120-page36 | |
| Date | 15th December 1932 | |
| To K.{Mr Kilner} from K.{Mr Kilner} c. Sr. Smm. Hs.{Lord Ernest Hives - Chair} Hy.{Tom Haldenby - Plant Engineer} re Peregrine Cylinder Head. -------------------------- It is found that for the purpose of getting a good black enamel finish on cylinder block and head, castings have to be fettled and scratch brushed to a higher degree of finish than was originally expected, and that this is the best way of tackling the job instead of relying on the filler to cover up casting blemishes. Because of this it is proposed by the shops to machine some portions of the outside surface of the cylinder head as where they can clean up such surfaces by a rough milling cut, such as on either side of the valve rocker gear recess, it means an economy as compared with finishing by other methods. The 20/25 cylinder head is a much simpler piece to finish than the Peregrine since its manifold faces do not stand out from the body of the casting and with a view to reducing the difficulty of the Peregrine it is suggested that a modification to the shape of the water jacket might be considered, as shown on Zec.3301 in which the sloping side of the water jacket is boxed out as far as possible to envelop the features of the inlet pipe flanges, and all bosses and other protuberances are reduced wherever possible to recesses below the surface. This last mentioned eliminates the operation of hollow milling around such bosses for cleaning up purposes. The induction pipe flanges it is also suggested should be of the more simpler form shown. The reduction in finishing time brought about by these changes for fettling, filing and emery dress is from 13.5 to 9 hours for cylinder head and induction pipe only. It is true that the extension of the water jacket adds more wetted surface to the induction pipe bends, which is not desirable, but the amount of increased heating, we believe, is not in direct proportion because the conductivity of the present casting probably conveys almost as much heat to the gas. The addition otherwise to the cylinder head core is not unwelcome. Slight modifications are necessary to the features for carrying the ignition wiring, and these are shown on the drawing. | ||