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 adjustments for a 20/25 HP car with a high compression engine.
| Identifier | ExFiles\Box 5a\5\ 05-page118 | |
| Date | 3rd May 1930 | |
| COPY. Hs{Lord Ernest Hives - Chair}/AJL. From MX.{John H Maddocks - Chief Proving Officer} c. EY. K57 Mx.{John H Maddocks - Chief Proving Officer}/T/3.5.30. X.5770 X.5771 X.5680 IGNITION TIMING ON HIGH COMPRESSION 20/25 HP. CAR. Ref: Hs{Lord Ernest Hives - Chair}/AJL/W.16.4.30. As the result of some further experience on the running of these chassis on Production Test, we are definitely of the opinion that we should not send out cars unless the ignition control range is altered to suit the recommended timing. Our reasons for this statement are - (1) If the ignition lever is retarded a very small amount the power falls off considerably. (2) As it is agreed by you that in the fully retard position the battery ignition will be very late, we should say very definitely that no customer would be able to start the engine up by hand with ignition fully retarded, fully retarding the ignition being the obvious thing to do when hand starting. With regard to the magneto ignition, we find there is considerable detonation with the recommended timing of 5° PTDC. Incidentally, your recommendation with regard to initial setting appear rather inconsistent in that you recommend that battery ignition 17° late and magneto ignition 5° later than on the standard compression engine. MX.{John H Maddocks - Chief Proving Officer} | ||