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 changes and reasoning for engine components like cams, rockers, and cylinder blocks.
| Identifier | WestWitteringFiles\Q\January1927-March1927\ 37 | |
| Date | 9th January 1927 | |
| R.{Sir Henry Royce} FROM E.{Mr Elliott - Chief Engineer} WEST WITTERINGHenry Royce's home town. CHICHESTER. ANGLETERRE. 9th. Jan. 1927. Although it may not appear so on inspecting LeC.2351. we passed through the same stage of reasoning as outlined in your memos. with a view to making the rockers interchangeable and of the type you describe. We however assumed the cams could be spaced with not less than .250 in between and on this basis we found that the cylinder blocks, camshaft brackets, and valve gear cover all required alteration. Since receiving your criticisms we have learned from Derby that the cams could be spaced .200 and subsequently .125 in between. This, and the use of 1.300 dia. valve springs helps the scheme considerably and we attach herewith a print of LeC. 2363. shewing the progress up to date. We have arranged .150 between the cams on this scheme and .125 clearance between tappet nuts and adjacent levers. The centre distance of the exhaust rocker bar has been decreased from 2.225 to 2.200 and the inlet increased from 2.125 to 2.200. This means more room is required on the exhaust side of the cylinder block. By using longer studs for securing the valve gear cover however it appears likely that we can avoid altering the cylinder block at this point. Regarding the camshaft brackets the present intermediate pattern are OK. fitted with shorter bearings, the rear one only requires cutting back, while the front bracket requires a new forging and a slight alteration to the shape of the valve gear cover at the front end. It is likely that the existing cylinder facing and block will be satisfactory but this we shall know tomorrow (Monday.) It would be an advantage to lengthen the rocker bosses on one side as in sketch. We should then be in a position to use 1.400 valve springs if required by milling away bosses for clearance. E.{Mr Elliott - Chief Engineer} | ||