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).
Ignition timing settings at various RPMs and analysis from bench tests on a Packard car.
| Identifier | ExFiles\Box 37\1\ scan 076 | |
| Date | 25th June 1920 | |
| Contd. -2- Hs{Lord Ernest Hives - Chair}7/LG25.6.20. _____________________________________________________________________ R.P.M. Ignition. Point. _____________________________________________________________________ Stationary. 8º B.T.D.C. _____________________________________________________________________ 500 12º. _____________________________________________________________________ 700 14º _____________________________________________________________________ 900 17º _____________________________________________________________________ 1100 19º _____________________________________________________________________ 1300 20º _____________________________________________________________________ 1500 22º _____________________________________________________________________ 1700 24º _____________________________________________________________________ 1900 27º _____________________________________________________________________ 2100 28º choc-a-block. _____________________________________________________________________ The standard thiming of the battery ignition on the Packard car is such that with the control lever fully retarded the spark takes place 21º after T.D.C. if the ignition lever is fully advanced the spark takes place 8º B.T.D.C. We found on the Bench Test that this setting of the ignition gave us the best results. It was, however, necessary to run the ignition hand control fully advanced all the time. As long as we had the hand control fully advanced, we could not find any advantage at any speed from 300 to 2500 revs. if we altered the ignition by hand. We tried setting the ignition another tooth advanced and at found no advantage/any speed. The 20º range on the automatic advance gave us all we required for full throttle condition of running but in order to obtain the best slow running it was Contd. | ||