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).
Detonation issues and recommended ignition timing adjustments for the Phantom II model.
| Identifier | ExFiles\Box 65\1\ scan0232 | |
| Date | 6th November 1929 | |
| COPY. X7680. To Ry. from Hs{Lord Ernest Hives - Chair}/AJL. c. Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} c. Mx.{John H Maddocks - Chief Proving Officer} EP.{G. Eric Platford - Chief Quality Engineer} Hs{Lord Ernest Hives - Chair}/AJL6/AD6.11.29. X7680. PHANTOM II IGNITION SETTING AND DETONATIONS. The present ignition timing on Phantom II is 12° B.T.D.C. when the ignition lever is at the top of the quadrant. Both magneto and battery ignitions are timed at this point. Detonations are rather pronounced and have been complained of after cars have run two or three thousand miles. If either ignition is used singly, detonations are very much less, the power is also considerably reduced. Retarding both ignitions 5° is a cure for detonations but at the expense of power, 3 to 4 H.P. is lost at the road wheels at high speeds and 1 to 2 at low speeds. This loss is definitely appreciable on the road, we could not recommend retarding both ignitions. The alteration which we could recommend and which has already been accepted on one or two cars by Sales is to retard the magneto ignition only by 5°. This is not quite so effective as retarding both, but no loss of power is detectable under road conditions. The recommended ignition setting is therefore battery :- 12° B.T.D.C. magneto :- 7° B.T.D.C. Hs{Lord Ernest Hives - Chair}/AJL. | ||