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).
List of specifications for various Wraith engine units, numbers 7, 8, 9, and a Wraith II unit.
| Identifier | ExFiles\Box 155\2\ scan0270 | |
| Date | 18th November 1938 | |
| -3- WRAITH III NO.7 UNIT (26.G.VI.) Up-to-date crankcase. W/M main bearings as run 15,000 miles. Std. cylinder block. Std. AC.9 die cast thin section big ends. AC oil filter with modified strap. Small std. valve cylinder head but obsolete construction. Special rocker joint (Marseline). Motor Component S/SLV inlet valves. Std. increased inertia camwheel. Delco distributor. WRAITH III NO.8 (25.G.VI.) Up-to-date unit as No.7. Pistons with high pressure comp. and scraper rings, L section 2nd. ring. Obsolete AC.6 thick section big ends with keyed shims. Obsolete Fabroil camwheel. Small valve head, but with obsolete construction. No. 9 (29.G.VI.) Up-to-date unit including:- Std. thin section big ends but in AC.6. AC oil filter. Std. increased inertia camwheel. Neuprene bushes under rocker cover nuts. Std. strengthened small valve head. WRAITH II No.1 UNIT TO BE USED FOR ADAPTION OF KESTREL SUPERCHARGER ON RIG. Obsolete unit of 25/30 construction other than modified lower half with sludge trap. External gauze pressure filter. | ||