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).
Methods for accurately finding the engine's top dead centre (TDC).
| Identifier | ExFiles\Box 43\3\ Scan176 | |
| Date | 24th August 1928 guessed | |
| contd :- -3- A very accurate method of finding the firing top dead centre (valves closed) can be arranged by filling the combustion space with oil, using a short length of glass (or metal) tube fitted in a sparking plug body in the inlet position - a dummy plug being used in the exhaust position. If the inlet opening top dead centre (beginning of induction stroke) is required on A1. say, then the oil tube method should be used in A6. cylinder. (Sufficient oil must be run into the cylinder to make the level visible in the tube when turning the engine backwards and forwards over the top dead centre position - which can be noted when the level is highest in the tube.) If a mechanical (pointer type) top dead centre indicator is used, reasonable accuracy can only be obtained by turning the engine backwards and forwards over the T.D.C. position and marking the thrust housing each time the pointer passes the M.A. mark (or a position corresponding to a substantial piston movement) before and after T.D.C. If the distance between the two points on the thrust housing is bisected the T.D.C. position will be obtained to within 2° crank movement. hs{Lord Ernest Hives - Chair}/V.Halliwell. | ||