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).
Issues with a specific valve, comparing water-jacketed and exhaust-heated throttles, and engine warm-up performance.
| Identifier | ExFiles\Box 72\2\ scan0052 | |
| Date | 15th October 1925 | |
| Oy6-E-101525 -2- October 15, 1925. The idea is that the thin copper pipe will give quick warming up with-out the valve in exhaust and without excessive intake temperatures. We dislike this valve because (a) we hear that you dislike it, [Handwritten note in margin: Never had throttle Buick cp no special] (b) on every car of any make that uses it, it eventually sticks or rattles, (c) the intake temperatures under long idling or slow running go far above 130°F.{Mr Friese} which we find about the limit if detonation is to be avoided on 4 to 1 compression. (d) Driving on the hand throttle, which will be done whether we like it or not, leaves the valve closed and gets the engine very hot. Water Jacketted Intake Pipe. Hulley tells me you were talking of using a water-jacketted pipe with a higher compression. The only comment we can make is that we are just putting through a run of 100 sets of exhaust heated throttles for selling to owners of existing cars with the water jacketted throttle. Reasons: Quicker warming up. Therefore less dilution. Less piston knocks at starting. When running the engine is much smoother due to better distribution. A water-heated throttle will not warm up in 5 miles running in winter with the shutters closed. With the exhaust heated throttle (without butterfly in exhaust) the car can be run normally in about 1/2 mile from the start and before the needle of the thermometer leaves the starting mark (100°F.{Mr Friese}). It is useless to tell a man to warm up the water before starting as in winter in a cold garage even with shutters closed it cannot be done under 10 minutes. Extra Oil. The engine needs extra oil operated with the pilot jet, to prevent cold- | ||