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).
Engine unit modifications for the Wraith III model.
| Identifier | ExFiles\Box 6\6\ 06-page387 | |
| Date | 1st December 1937 | |
| By/DS. Are you dealing with this. W. Ilder Rm{William Robotham - Chief Engineer}/SWDL{Len H. Swindell} ANSWERED C.Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} 6 Nov DA.{Bernard Day - Chassis Design}12/G.1.12.37. WRAITH III - ENGINE UNIT. Referring to the request in memo Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}4/ MOL.25.11.37. will you please make the modifications as follows to comply with the suggestions :- (1). Valve timing markings. This has been referred to Da{Bernard Day - Chassis Design}/TWN. who has instructed G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Department to make improvements. (2). Crankcase expansion allowance in the holes for studs holding cylinder block to crankcase. The four holes for studs to Lcd.5538 should be increased to .375" diameter, this will allow for a differential expansion or contraction between cylinder block and crankcase of .025 which is sufficient to allow of an increase in temperature above normal of 260°C. We do not consider it necessary to use shouldered studs to allow sliding surfaces, as the cylinder and crankcase are already held tightly together by all the normal cylinder studs. The holes at present called for on cylinder block detail are .3437 diameter and these should allow of a temperature rise of 145°C. (3). Extra Keyway in Camshaft Timing Wheel Hub. There are two points in connection with this suggestion to be considered before it is adopted :- (a). The possibility of wrong assembly when gears have been dismantled at any time, as there will be two positions for wheel on camshaft. This might be dealt with by marking. (b). The relationship of the cam balancer to the cams will be upset. The maximum error could be 3° on the camshaft. This may not be considered sufficient to upset the balancing effect. (4). Tappets lifting with push rods out of crankcase. We shall be sending a design for this shortly. | ||