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).
Secret memo outlining modifications for the 'Japan 3' engine, concerning the connecting rod bolts and cylinder head design.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan286 | |
| Date | 4th February 1931 | |
| A.{Mr Adams} FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD} HORE C. to HS.{Lord Ernest Hives - Chair} HY{Tom Haldenby - Plant Engineer} SECRET JAPAN 3. ENGINE. x5770 We send you herewith further print of LeC. 2853., shewing certain modifications suggested by HY.{Tom Haldenby - Plant Engineer} and RHC.{R. H. Coverley - Production Engineer} to facilitate production, together with some other points which we set out as follows: CONNECTING ROD BOLTS. Derby prefer the scheme shewn for preventing the heads from turning as being the easiest to produce. We see no objection provided the thickness of the metal on the rod at the point where the section changes is well maintained. CYLINDER HEAD. (a) Derby wish to reduce the height of the cast iron wall standing up round the valve gear to a minimum as this feature is a source of casting scrap. We had the same idea in mind with a view to reducing the weight and we have therefore cutout the feature which was holding this face up. (b) Derby prefer the water jacket on the induction side to make one slope from rocker box to base as in sketch to allow for bigger cores and to simplify the moulding around the inlet flanges. We are in agreement with this as we feel there is perhaps not sufficient room in our cylinder heads for unimpeded water flow unless we tap off at intervals into an external water pipe. At the same time we have increased dimension A.{Mr Adams} above the exhaust bend which had become less than we thought desirable. (c) Derby wish to bring down the induction flanges below the top face. This allows them to surface grind heads on a circular table. We have been able to do this by reason of the next item, and by canting the flanges over a little. (d) Derby asked if the spark plug drilling on the induction side could be same as exhaust. We see no objection to this as we do not think the difference in the plug position could be detected in practice, and also this item helps (c). (1) | ||