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).
Simplified design for Phantom III tappets without tappet springs.
| Identifier | ExFiles\Box 96\2\ scan0251 | |
| Date | 10th August 1937 | |
| E.{Mr Elliott - Chief Engineer} Dept. c. to Rm.{William Robotham - Chief Engineer} c. to RD. Swdl{Len H. Swindell} Poles Da.{Bernard Day - Chassis Design}7/G.10.8.37. 354. PHANTOM 111 - SIMPLIFIED TAPPETS WITHOUT TAPPET SPRINGS. Herewith LeC.5667 T Section Tappets in broached guides. Will you please detail and instruct this to be made experimentally for use on an engine without hydraulic tappet adjustment. It will be noticed that this design does not call for the use of tappet springs, and is not suitable for their application, so that additional valve spring load will probably be required, even so, the valve spring loading should not be greater than for the present engine with hydraulic valve adjustment. The tappet block is interchangeable with the present type of block, but demands longer fixing studs and also longer push rods. The tappets could be tried without the oil catch trays, which should only be used if it is found necessary owing to excessive wear of tappet or push rod end. It may also be worth while trying a set of tappets with the chromium plating deleted now that the chance of base circle loading has been removed by not using hydraulic tappets. The estimated saving in cost per engine by this design is £9. as compared with the present production costs, which include sand cast tappet blocks. There is already a simplified design of tappet clamp and block to LeC's 5371 and 5642 being tried in the Experimental Department for use with tappet springs, but this new design shows a further considerable reduction in cost. DA.{Bernard Day - Chassis Design} | ||