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 sheet for Wraith III units No. 5, 6, and 7.
| Identifier | ExFiles\Box 155\2\ scan0200 | |
| Date | 7th February 1938 | |
| -4- Wraith III No.5 Unit (28.G.VI) Contd. Inlet valves S.65 material. Rs. {Sir Henry Royce's Secretary} 540 Swedish wire springs coiled at RR. Rm. {William Robotham - Chief Engineer} 400 top washers. Bottom tappets in I/C blanks produced by C. & B. Smith. Conical base housing for push rod, latter likewise conical. Vauxhall copy camshaft giving a lift of .325 (Rs. {Sir Henry Royce's Secretary} 608). Unhardened S/ZNX timing gears. Relief valve spring E.88790 High pressure. " " " L.X.26174 Low " AC. bye pass oil filter inlet from main press outlet to rocker pressure. Extra cam keyway fitted to give finer timing. Wraith III No.6 (Later to be fitted in 27.G.VI). Crankcase to suit loose liner cylinder block but modified by eccentric studs to take up-to-date solid block. Adaptor to take large AC petrol pump. Main bearings in billet cast AC.6 with RR.56 shims. Rear main bearing with grooves and drain holes Rm. {William Robotham - Chief Engineer} 485. No.1 - 6 tappet guides A {Mr Adams} /P. 7 - 12 RR.50 alloy. Hykro crankshaft with std. large balance weights. Big end bearings AC.6 as designed with keyed shims. Std. 25/30 pistons and rings. Std. Wraith solid cylinder block. Unhardened engine gears S/ZNX. Valve springs EB.3256. Swedish wire coiled at RR. 1 - 6 Blue (new machine). 7 - 12 Red (old machine). Chevrolet type of bottom tappets with large spherical. Latest RR. ignition distributor Dm. {D. Munro} 426. Wraith III No.7 Unit (26.G.VI) (15,000 miles). First unit with up to date crankcase without tappet bushes. Std. crank and large balance weights. No.s 1, 3 and 5 connecting rods and big end bearings without flanges. Nos. 2, 4 and 6 with flanges, bottom types of bearings having .062 section. 5/16 push rods. Nos. 1 - 6 EB.3256 valve springs in Swedish wire coiled at RR. Nos. 7 - 12 EW.1428 std. Wraith (S/CV). Cft. length grummets. Ex camshaft end thrust plunger. Cam balance plungers removed. Damper drilling arrangement as std. Wraith no holes in rim and 8 holes in centre plate. | ||