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).
Timing gear 'sing' and 'rattle', and the feasibility of using Fabroil gears for the 4 1/4 Litre Bentley production.
| Identifier | ExFiles\Box 82\4\ scan0281 | |
| Date | 15th March 1936 | |
| EP.{G. Eric Platford - Chief Quality Engineer} Mr. (crossed out) C.E. (crossed out) c. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} d.{John DeLooze - Company Secretary} Wor.{Arthur Wormald - General Works Manager} HARDY. BY.3/G.15.3.36. re 4 1/4 LITRE BENTLEY PRODUCTION. -------------------------- Referring to EP.{G. Eric Platford - Chief Quality Engineer}13/MR.12.3.36. and dealing first with the proposal made towards the end of the memo that Fabroil gears might be used, we would like to point out that for the design of cam balancing which is in use in both these chassis, it is not possible to fit in the extra dimensions in certain places called for in a Fabroil gear. If a Fabroil gear is to be used it will mean considerable re-design which cannot be considered at this stage. In regard to the question of timing gear 'sing' and 'rattle', I am afraid that with the existing design of gears there is no probability of avoiding one or other of the above faults. If the gears were produced on the tight side, rattle is eliminated and sing is produced, if sing is avoided by increasing the running clearance slightly undoubtedly rattle develops. In discussing this matter with Mr. it is evident that the rattle referred to is produced when driving on top gear under heavy loads, and would appear as Mr. suggests to be more a function of the crankshaft synchronismthan normal gear rattle. This matter has had attention already at Mr's suggestion from the point of view of whether the springs in the slipper flywheel could be increased, but apparently Design consider they have got the last bit possible out of the existing dimensions, but they will no doubt give the matter attention again in the near future. It certainly would appear that the rattle at 20 miles an hour under load is not even remotely connected with the rattle produced as a result of camshaft movement and vibrationon the pinion driving the dynamo. Apparently this rattle has been almost suppressed by the introduction of the cam balancer. BY.{R.W. Bailey - Chief Engineer} | ||