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).
Instructions for modifying a governor with new springs, loads, and engine timing adjustments.
| Identifier | ExFiles\Box 65\1\ scan0191 | |
| Date | 12th December 1926 guessed | |
| contd :- -2- E.74990 to be cut off after moving through 24°. The governor weights should be fitted with the modified form of springing to which gives only half the angular spring deflection. The springs which should be fitted are E.75071. When these springs are fitted up on the governor, the loads at the end of the lever taken as previously with a spring balance should be :- (1) Load to bring weights together = 5 lbs. 4 ozs. (2) Load to let weights separate = 3 lbs. 2 ozs. (3) Load to just start to lift lever from zero position = 12 ozs. We find that a return spring of 6 to 9 lbs. over the relay is insufficient. It will therefore be necessary to fit a spring as nearly as possible 9 to 12 lbs. in this position to replace E.74947. With the new relay it is necessary to fit a return spring to the magneto. The spring we find satisfactory is E.74839 which should be set up to give a load of 2 lbs. on the magneto arm in the fully retard position. The timing of the engine is altered with the new type of relay from 20° B.T.D.C. to 17° B.T.D.C. The setting of the controls, however, remains as previously. We attach a copy of the ignition advance curve which should be obtained with the new relay. This curve should be taken with a dead load of 18 lbs. on the large piston of the relay. lis/W.A.Robotham. | ||