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).
Instructions for modifying a J.II cylinder head to fit a J.III engine.
| Identifier | ExFiles\Box 103\4\ scan0109 | |
| Date | 17th January 1933 | |
| c. RHC{R. H. Coverley - Production Engineer} c. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. BY/CS. Y 5050. BY/SS{S. Smith}1/N.17.1.33. Re: J.III - Cylinder Head. In order to fit the J.II ( 3.250 bore) type of Cylinder Head on the J.III ( 3.400 bore) engine, will you please instruct the necessary castings to the attached blueprint Hs.{Lord Ernest Hives - Chair}908. The existing pattern E.59068 is modified by increasing the thickness of the floor by .150, thus keeping the compression ratio 5.750 to 1. When this cylinder head is fitted it will be necessary to increase the length of the push rods, water jacket tubes and cylinder studs as called for on the drawing. Tracing attached for keeping in low files BY/SS.{S. Smith} | ||