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).
Summary comparing the existing push-rod overhead valve engine with a proposed 6-cylinder overhead camshaft design for future chassis.
| Identifier | ExFiles\Box 134\2\ scan0074 | |
| Date | 1st September 1936 | |
| -5- Summary. For fifteen years we have been using the existing push rod type of overhead valve engine exclusively in our chassis. It has served us exceedingly well and may do so for some time to come. As an all aluminium unit on the J-III lines it can be made longer to simplify casting, and to accommodate larger valves without a great increase in weight. Recent investigations indicate that it is no more imperative to have silent tappets with all aluminium construction than with a cast-iron unit. Its major drawback for the future seems to be the inherent difficulty of getting two inlet valves in place of one. The 6-cylinder overhead camshaft unit now on test should provide us with the necessary piece of experimental apparatus to determine the relative merits of this type of design. We still think it is worth while laying out the high power type of engine on the drawing board as a 6-cylinder unit to supplement the single cylinder results which so far credit this arrangement with certain definite advantages. If any new unit for the Wraith is to be designed forthwith, it seems clear that the only construction of which we have sufficient experience to utilise at present is the J-III type. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||