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).
Analysis of competitor engine designs from Cadillac and Buick, with discussion on silent tappets, engine configurations, and coachwork.
| Identifier | ExFiles\Box 178\2\ img198 | |
| Date | 24th February 1934 | |
| -2- The Cadillac 16 power unit is so much better than the 12 that I wired you re bringing it back. We might as well have a good standard to aim at with our twelve. In spite of its great weight its performance is very good; it has a harder mount than the 12, but is smoother, its intake and exhaust silence is better. The price is 7,000 $ less 30%. If you want to get it into England on a Triptique or get Cadillacs to run it some miles and then pay duty on it second-hand, please let me have full particulars of method to employ to avoid trouble with the Customs. Silent Tappets. Cadillacs have our trouble if valve springs surge. Their cure is to change the valve springs. They use a toe off .011 with their silent tappets of duration approx. 40 crankshaft degrees but I will get opening curve. Sixes or Eights. Cadillacs, with low taxation restrictions, no penalisation for increasing number of cylinders, are thinking only straight eights and sixteens at the moment. I think they are designing a sixteen of about 380 cu.ins. with side valves, to sell for less than 4,000 $. At the moment they seem to favour side valves as making a lighter and much cheaper engine with little loss of efficiency over the O.H. I think that this is a direct reflection on the present poor efficiency of the O.H.V. and we must put it as far ahead of the side valve engine as it belongs. I still feel that we must test the 4 litre Bentley O.H.V. inlet side valve exhaust on a single cyl. unit because if you use a cast-iron block, alum. head and crankcase, you don't lose much weight and might get a simple, silent and efficient unit. Hudsons are carrying on research on this type of engine. Buicks are coming out with quite a small eight, about 240 cu.ins. which will be right in the 20/25 size. Coachwork. It is becoming increasingly evident that the Coachbuilt body as we know it will not be able to compete with the steel body as a means of re-inforcing the chassis. This means that with independent suspension we shall probably have to add costly stiffening to our frame instead of using the body as they do over here. The more I see of the best grade steel bodies here, the better I like them for absence of rattles and increase of frame rigidity. | ||