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).
Build specification for a Wraith III No.10 engine unit.
| Identifier | ExFiles\Box 108\2\ scan0107 | |
| Date | 17th June 1938 | |
| 600. To HPS.{Horace Percy Smith - Experimental Factory Mgr} c. to G/RB.{R. Bowen} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}14/JH.17.6.38. WRAITH III No.10. Will you please build another new unit to the following specification, which will take the place of an obsolete engine in a car. (1) .4 Carbon crankshaft as B.III No.5 but having of course Wraith balance weights. (2) Crankcase suitable for fitment of Vandervell main bearings as B.III No.5. (3) All A/C parts crankcase and lower half etc. to be in L.5. alloy. (4) Forged to size connecting rods as B.III No.5. but with die altered to suit fitment of standard thin section A.O.9. die cast big end bearings. (5) Little end bushes will be supplied by Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} and will be a product of Vandervell's. (6) Camshaft EXS.767/8 which deletes the use of loose bearings and runs direct in the crankcase, we have issued memo. Rm{William Robotham - Chief Engineer}/Swd./7/JH.16.6.38. asking for a sample to be produced. Cam form to be as EB3466 (7) Camwheel to E.X.771 which is in similar cast material to camshaft. (8) Push rod as for B.III No.5 unit, that is forgings in .4 carbon steel as obtained from the Belgrave Eng. Co. (9) Rockers bushes with W/M strip bearings which will be supplied by Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} (10) Cylinder head to be prepared for small valves i.e. 1.3 dia. exhaust and 1.5 dia. inlet and actual valves will be specified later. (11) .030 Klinger cylinder head gaske.. | ||