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).
Reduction of end play tolerance in the spring drive for the 40/50 Chassis to improve engine quietness.
| Identifier | ExFiles\Box 79\3\ scan0119 | |
| Date | 27th March 1924 | |
| Handwritten: V3271 BY (Strikethrough) c. SFT.{Mr Swift} (Strikethrough) c. Hs.{Lord Ernest Hives - Chair} EP{G. Eric Platford - Chief Quality Engineer}10/H27.3.24. re. 40/50 Chassis. End Play in Spring Drive. We have for some time found that it is of considerable importance to make sure that the train of gears from the crankshaft to the magneto pinion or distributor drive is free from slack. It is also essential in order to obtain sweet and quiet running of the engine to see that the engine gears are satisfactory in this respect before finally passing. We find that to obtain this it is essential for the end play of the crank pinion to be properly controlled, and this is very much influenced by the end play in the spring drive. Handwritten in margin: ? "Bus" knocks At present the drawings allow this end play to be from .005" to .010", but SFT.{Mr Swift} did arrange some time ago that he would try to work on the minimum limits, and we have certainly found that this has given an improve-ment, but in several cases where the engine has been awkward so far as certain knocks are concerned, we have found that by reducing the end play in the spring drive the fault has been overcome or made quite passable. We have made tests on various engines with the end play of the spring drive reduced to .003". These engines have been well tested and thrashed on the dynamometer and unit bed, and as long as the bush has sufficient radial clearance, there has been no trouble of seizing up, whereas the engine has been improved as regards quietness and sweet running. We shall be glad, therefore, if you can arrange for the end play of this bush in the spring drive to be reduced so that the limits are from .004" to .006". We shall also be glad if definite instructions can be given to the Works pointing out the importance of this end play, and instructing for same to be checked on all spring drives when building up to see that it comes within these limits prior to the fi xing of the springs for the spring drive or the damping device. Will SFT.{Mr Swift} in the meantime please give us all the help possible in dealing with engines on test which are giving trouble in this respect, by altering the end | ||