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 details for three different Wraith III engine units (No.2, No.3, and No.4).
| Identifier | ExFiles\Box 155\2\ scan0155 | |
| Date | 23th September 1937 | |
| 4. Wraith III. No.2. Unit. (Test Bed) W/Mt. main brgs. RR.56. shims. A.C.G. Big end Bearings. Unhardened engine gears in S/ZMX. Cylinder head obsolete type without fan mounting. S/SLV. inlet valves and RL.965 (stell.) exh. valves. Rm.{William Robotham - Chief Engineer}260 Valve springs. Bottom tappets in I/C (RR.) Chev. type Ex.27960 with push rods to suit. Tappets square and not tilted. Wraith III. No.3. Unit (24.C.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 RL.965 (stell.) exhaust valves. Camshaft with extended toes RS.{Sir Henry Royce's Secretary}607. Bottom tappets in I/C (RR.) Chev. type Ex.27960 with push rods to suit. Tappet guides tilted by boring 45'. RS.{Sir Henry Royce's Secretary}540 springs in Swedish wire coiled by RR. modified base coiling. Rm.{William Robotham - Chief Engineer}400 top washers. 5/16 dia. push rods Ex.28466. Wraith III. No.4. Unit. (27.C.VI) 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/ZMX timing gears. Camshaft with extended toes RS.{Sir Henry Royce's Secretary}607. Alum adaptor plate between the crankcase and the cylinder block this being std. 25/30, likewise cylinder head, induction system, rockers, etc. Increased inertia flywheel ring Ex.28322. | ||