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).
Standardization and application of self-adjusting tappets on various engine models.
| Identifier | ExFiles\Box 17\6\ Scan181 | |
| Date | 6th February 1934 | |
| X7060 W/S. To Sg.{Arthur F. Sidgreaves - MD} from E.{Mr Elliott - Chief Engineer} E.10/HP.6.2.34. c. Wer. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} Bn.{W.O. Bentley / Mr Barrington} re Self-Adjusting Tappets. Replying to Sg.{Arthur F. Sidgreaves - MD}22/E.5.2.34, the scheme we have worked on mostly and which we are pushing forward for standardization is similar to that used by General Motors on the Cadillac and has an eccentrically mounted Rockers, the eccentricity being adjusted by spring controlled plungers in cylinders. The springs follow up the changes in clearance due to expansion, while the operational loads of the valve gear are carried by oil under compression trapped by the plungers in the cylinders. We are getting very good results from the gear of this type that we have running on the J.3. engine and we have also a similar set running on Vulture. The 10,000 mile P.2. we are building at the moment will also be fitted with hydraulic tappet mechanism of this type but the material for S.2. series of Phantoms is being ordered with the standard valve gear owing to the fact that this material has had to be put on order and we are not sufficiently far forward with the self-adjusting gear to put it on S.2. series. S.2. series goes on test at the beginning of May and at the proposed output of 4 per week should finish by the end of October. The next series which will go on test at the beginning of November will be earmarked for this modification. We have not instructed this scheme for the 20/25 as it is not required to anywhere near the same extent as on the larger engine. In the case of the SpectreCodename for Phantom III, although the conditions are very much the same as on the 20/25 the multiplicity of the tappet gear demands some self-adjusting scheme, and the SpectreCodename for Phantom III has accordingly been instructed with the same scheme applied. E.{Mr Elliott - Chief Engineer} | ||