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 the automatic and hand control ignition advance on a Packard 12-cylinder engine, with test results.
| Identifier | ExFiles\Box 37\1\ scan 075 | |
| Date | 25th June 1920 | |
| X 3199 Extract from Hs{Lord Ernest Hives - Chair}7/LG25.6.20. X.435. RE PACKARD 12-CYLINDER ENGINE. X.3949 X.3199. X.1819. A point on the Packard engine which we had not realised before is the fact that there is an automatic advance, as well as the Hand control for the ingition. As it is arranged the Hand Control gives 29º advance on the flywheel - the automatic advance gives 20º on the flywheel. With the Hand Control both the contact breaker cam and the rotors for the 6-cylinder distributors are advanced but with the automatic advance only the contact breaker cam is advanced and not the distributor rotors. One can see that it is not necessary on the automatic advance to advance the high-tension rotors so long as they have sufficiently long contact to avoid the spark jumping. We have taken a test with the automatic advance on the engine to see at what point the spark occurs at different speeds. To do this we ran the engine on six cylinder. On the distributor for the other side we fitted a special ring which was marked off in degrees. We could tell on this ring the point at which the spark occurred.:- Below are the results:- R.P.M. Ignition Point. Stationary. 8º B.T.D.C. 100 8º 300 10º Contd. | ||