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 recurring complaints of damper knocks and the actions taken.
| Identifier | ExFiles\Box 107\2\ scan0102 | |
| Date | 10th June 1938 | |
| ...From REC/OTH. C. EH/GWH.{George W. Hancock - Head Chateauroux} REC/GWH.{George W. Hancock - Head Chateauroux}1/MC.10.6.38. RE. SHOCK DAMPERS In view of recurring complaints of damper knocks, it was requested, sometime ago, that several sets of these be returned to Derby for investigation. This has now been completed and the action taken, with regard to each set of dampers is given in the attached report. Where possible the dampers were fitted to a chassis and tested on the road in addition to being rig tested, but road tests could not be carried out in every case since chassis of suitable types were not available. The remaining sets were dismantled by the Repair Dept., and submitted for inspection, then reassembled. Three sets of dampers tested here have since been fitted to customers' cars and no further complaint has been made to date. It is interesting to note that the dampers from 3-CP-10 were returned on 13.4.38. with complaints of knocks and another pair of dampers were fitted. One of the replacement dampers was again returned on 7.5.38. with similar complaint, but neither the original nor replacement dampers showed any signs of wear sufficient to cause knocking. From this it would appear that certain cars are more prone to this fault than others. It has been claimed in the past that Depots have cured damper knocks by fitting new bushes and scraping to size, but our investigations appear to prove that worn bushes are not responsible for this trouble. In fact no replacements were considered necessary in any case, although certain bushes were found to be worn slightly beyond drawing limits, but not enough, however, to justify replacement. Dampers were merely cleaned and reassembled. The dampers which were sent to Derby for investigation are being submitted to Repair Department Stock and will be used as replacements on cars, and future performance should be particularly noted. As no further information can be obtained from tests carried out at Derby, we suggest that, until some more definite diagnosis of the complaint has been effected, Depots should revert to the usual procedure with regard to damper repairs. RHC{R. H. Coverley - Production Engineer}/G.F.Houliston. | ||