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).
Issues with valve gear noise and potential solutions involving tappet adjustment and camshaft design.
| Identifier | ExFiles\Box 102\5\ scan0151 | |
| Date | 11th December 1933 | |
| x5090 To Sg.{Arthur F. Sidgreaves - MD} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} C. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} C. Dy.{F R Danby} FH. C. H.{Arthur M. Hanbury - Head Complaints} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}2/KT.11.12.33. 8207 VALVE GEAR NOISE. In view of the general concern regarding the silence of R.R. valve mechanism, we have carried out tests as in the attached report. We know that the automatic tappet adjustment is essential where much expansion takes place, as on the Phantom, but we believe that on the Bentley in particular, and possibly on the 20/25 also, we can make at least some improvement in the immediate future by tackling the camshaft only. It will be observed that the results show that the cam form does not accurately follow the drawing; we know that E.{Mr Elliott - Chief Engineer} is aware of this as it has been previously demonstrated, and he made a suggestion that the master cams should be ground from a hand finished former that should be eight times the final cam dimensions in order to overcome this difficulty. We think this suggestion well worth carrying out. The fact that the opening toe can be shorter than the closing toe, we think should be of material assistance in getting quiet tappets without loss of efficiency. We believe that if we are to avoid valve burning on the Phantom when we use the hydraulic valve gear, we shall require a new camshaft with a different toe. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||