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).
Continued instructions for checking ignition system quantities and timings for 20 HP and Phantom chassis.
Identifier | ExFiles\Box 32\5\ Scan081 | |
Date | 25th October 1928 guessed | |
-2- Contd. In the case of the 20 H.P. chassis, the only difference is that the hand advance range is 40° in place of 30°, and the position on the quadrant should be about 3/4 of the way down on the average of several engine stops, in place of 2/3. In the case of any chassis ignition system which does not agree with the above, the four quantities should be checked over to see which one or more of them is/are seriously wrong. A check should then be made that the engine is stopping on the average with crank inclinations at 50°-60° to the top centre. The late ignition timing should then be checked for 10° A.D.P. The make ratio should then be checked for .5 to .55, i.e. contact gap .017" to .021" and the hand range of ignition advance should be checked for the 30° in the Phantom case, and 40° in the 20 H.P. case. If all these quantities are right the breaks should occur on the lever as stated. The extent to which these quantities may individually be wrong whilst the others are right is as follows :- (1) A particular crank may have stopped as much as 50° B.D.P. (2) The full retard may be as little as zero degrees A.D.P. (3) The make ratio of the contact breaker may be as great as .58. Contd. | ||