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).
Scheme for modifications to the Bentley III camshaft.
| Identifier | ExFiles\Box 98\5\ scan0020 | |
| Date | 16th May 1938 | |
| 407. By/ALD.{F. Allwood - Experimental Design} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} Rm{William Robotham - Chief Engineer}/Swdl{Len H. Swindell}/R.16.5.38. BENTLEY III CAMSHAFT. Will you please detail a scheme to cover the following which we intend to try out. The modifications are in respect of the cast camshafts which we have had from the Midland Cyl. Co. for Wraith to EW.1416. (1) Camshaft bearings cast integral with the camshaft to run direct in the crankcase, thus deleting the A/P loose bearings. If bearing diameters are made to approximate with the existing bearing holes in the crankcase it will not be necessary to produce a special crankcase. The bearing diameters and the crankcase bores should be progressively larger by say .005 from the rear end to facilitate assembly. Sufficient clearance to be left between the bearings and the cams to form the latter. (2) Instead of the usual taper nose piece on which the camwheel is fixed, a circular flange to be used with a ring of studs on which the camwheel will be mounted. The circular flange will, of course, be cast integral with the camshaft. The camshaft to be retained by the end thrust plunger only, which should have a limited movement to prevent forward float of the gears in the case of the unit running backwards. As per the latest Wraith units no provision is required for the cam balancer. (3) Other than alterations (1) and (2) other mods required to the pattern for casting any future camshafts are:- (a) To cover the camshaft EB.3466 as well as EW.1416. (b) Leave .050 excess for casting where machining is to be carried out, and, say .010 excess where we are not going to machine. (c) Parts of the camshaft we do not intend to machine are - | ||