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).
Performance test report on a high compression engine, detailing the effects of ignition advance.
| Identifier | ExFiles\Box 5a\5\ 05-page101 | |
| Date | 29th November 1929 | |
| FILE x5771 HS.{Lord Ernest Hives - Chair} From Ho/Rn.{Mr Robinson} HS{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}2/AD29.11.29. STANDARD H.C. PERFORMANCE TEST. ENGINE. Effect of ignition advance 12-64. This car is fitted with a high compression engine 5.25 to one and a 11/30 axle ratio with 6" tyres on 19" rims. Its total unladen weight was 32 cwt. Full compliment of petrol was carried. The car was first run on magneto ignition, under which conditions it detonated very badly*. It was then changed to battery ignition with a set of 26° B.T.D.C. The detonation setting on this battery ignition was considerably less than on the magneto, but was still noticeable below 20 m.p.h. Tests up Ticknall and Stanton Hill, carrying two passengers indicated that the ignition setting of 26° was too far advanced, and a very definite increase in car performance, absence of detonation, and improvement in fuel, was arrived at by running with the ignition setting of 13° B.T.D.C. This was found to be the best setting for performance, there being practically speaking, no detonation from 10 m.p.h. upwards. Retarding the ignition further than 13° B.T.D.C. reduced the performance of the car. Magneto setting on this test found to be 41° B.T.D.C. * Standard battery ignition setting 26° Ignition advance Time up Pieston Hill. 26° 75.3/5 secs. 20° 73.3/5 13° 72.3/5 * 7° 75.2/5 He/rd. | ||