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).
Specifications and details for Wraith III engine units No. 3, No. 4 (Test Bed), and No. 5.
| Identifier | ExFiles\Box 155\2\ scan0224 | |
| Date | 3rd June 1938 | |
| -3- Wraith III No.3. Unit (24.G.VI) Cont'd.{John DeLooze - Company Secretary} AC.6. big end bearings. Crank with 2 - .125 holes in each pin. S/SLV inlet valves KE.965 (Stell.) exhaust valves. Camshaft with extended toes R.S.607. Std. Bottom tappets in V/C (RR.) Chev. type EX.27960 with push rods to suit. Tappet guides tilted by boring 45'. EB.3256 springs, 6 red and 6 blue. Bentley rockers adapted giving .350 lift. Delco Ignition distributor. Wraith III No.4 Unit (Test Bed). Obsolete crankcase but by use of eccentric studs std. block fitted. Cylinder block in Chrome Iron produced by R.R. AC.6 billet cast big ends, original thick section with keyed shims. Unhardened S/ZNA timing gears. Main bearings butt faced (no shims) Latest Attwater material camwheel std. with balancer deleted. Monikrom camshaft and end thrust plunger. Up to date large crank balance weights. No. 4 and 5 inlet valves in 7.5% chrome, forgings supplied by Belgrave Engrg. Co. machined all over. No.1 As 4 and 5 but unmachined on the back of the valve head. R.S.540 valve springs Swedish Wire (RR) .030 thick Klinger cylinder head washer. Up to date oil grooving and drain from the rear bearing. Delco Ignition distributor. Wraith III No.5. (28.G.VI). Obsolete type of crankcase but by use of eccentric studs std. solid bloc fitted. Vertical bored tappets with flat faces. Front face of cams machined back to C/L of tappet thus having .400 cam width. Std. crank and balance weights. AC.6 Billet cast big ends thin section. No shims. Std. flanged type. | ||