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).
Investigation into the cause of chunking noises in the drive, comparing a Buick with a 5-B-IV model.
| Identifier | ExFiles\Box 124\3\ scan0323 | |
| Date | 26th February 1935 | |
| 43317 To Hs.{Lord Ernest Hives - Chair} C to Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux}9/KW.26.2.35. Re Chunking in the Drive. We have investigated the reason why the Buick is so free from chunking in the transmission when taking up the drive and running slow. The primary reason is the even torque of the engine at slow speeds and freedom from misfires. Secondly, there are no driving dogs or splines on the rear axle shafts at the hub end. With one cylinder cut out on the Buick, the chunking noise is 50% less than what is heard on 5-B-IV. The absence of chunking is not because special attention has been paid to obliterate slackness in the transmission, as the following measurements will show :- Slack in clutch splines (rad. 2"). Buick .007" 5-B-IV .011" Slack in synchromesh drive Buick .020" 5-B-IV .014" Total slack at drive end of third motion shaft Buick .027" 5-B-IV .024" End play of third motion shaft Buick .007" 5-B-IV .010" Lift in rear bearing of third motion shaft Buick .000" 5-B-IV .010" Slack in the differential pinions and driving shafts, measured at wheel rim. Buick 3/16" 5-B-IV 1/4" Total slack in direct drive measured at wheel rim (rad. 10"). Buick 9/16" 5-B-IV 9/16" There is, however, no metallic noise from the driving shafts owing to the fact that Buicks use a semi-floating drive. The rear hubs are firmly attached to the driving shafts by a taper and key. Any metallic noise in the driving splines in the differential box is damped by the oil. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} | ||