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).
Specification and modification notes for Wraith III engine units No.2, No.3, No.4, and No.5.
| Identifier | ExFiles\Box 155\2\ scan0199 | |
| Date | 7th February 1938 | |
| -3- Wraith III No.2 (Valve endurance) Cont'd.{John DeLooze - Company Secretary} One .218 and one .125 hole in each crankpin. Tappet bushes 1 - 4 in RR.50 5 - 8 in I/C 9 -12 in A/F.{Mr Friese} Pistons with high press rings. Wraith III No.3 unit (24.G.VI). W/Mt. main brgs. RR.56 shims. A.C.G big end bearings. Crank with 2 - .125 holes in each pin. S/SLV. inlet valves RR.965 (Stell.) exhaust valves. Camshaft with extended toes RS.{Sir Henry Royce's Secretary}607. Std. Bottom tappets in I/C (RR.) Chev. type Ex.27960 with push rods to suit. Tappet guides tilted by boring 45'. EB.5256 springs. 6 red, 6 blue. Bentley rockers adapted giving .350 lift. Wraith III No.4. Unit (Spare Unit in shop). Wraith III crank and shaft etc. An extra .125 hole in each crankpin, original .2187 hole being retained. Tappet guide bushes bored at an angle of 45'. W/M.{Mr Moon / Mr Moore} main bearings. A.C.G. big end bearings with single centre hole. "Chevrolet" type of bottom tappets Ex.27960 with push rods to suit. Unhardened S/ZRX timing gears. Camshaft with extended toes RS.{Sir Henry Royce's Secretary}607. Alum adaptor plate between the crankcase and cylinder block this being std. 25/30, likewise cylinder head, induction system, rockers etc. Increased inertia flywheel ring Ex.28322. Rear bearing grooved for oil drain Rm.{William Robotham - Chief Engineer}458. Wraith III No.5 Unit (28.G.VI.)A An extra .125 dia. hole in each crankpin .2187 hole being retained. W/M.{Mr Moon / Mr Moore} main bearing with RR.56 shims. Big end bearings in A.C.G with single centre hole. No. 1 - 6 tappet bushes in A/C inclined 45'. No. 7 -12 " " in I/C Cylinder liners, No.1, 2, 3 and 4 Hepolite. No.5, and 6 Centricast. cont'd.{John DeLooze - Company Secretary} | ||