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 document for the Wraith III chassis, detailing changes to the engine and other components.
| Identifier | ExFiles\Box 6\6\ 06-page188 | |
| Date | 15th April 1937 guessed | |
| SPECIFICATION OF WRAITH III CHASSIS. ENGINE UNIT. New engine unit incorporating rearranged auxiliaries, flat bottomed tappets, Delco ignition, simplified fan and drive, lower half crankcase arranged for die casting high front engine mounting, wet liner type cylinder, standard starter motor and drive, more flexible rear engine mounting, differentially coiled valve springs in Swedish wire, exhaust valves in S/SLV, inlet valves in S/65, crankcase castings in L..5. material, no shouldered studs for main bearings and cylinder head, crankshaft with larger main bearings and present standard crankpins, 25/30 drop forged connecting rods, 4 port cylinder head with carburetter on steering side, 50% still larger oil pump with 22° helical teeth, coarse pitch. OPTIONAL. High pressure oil filter, A.C. with only main bearing oil passing through filter. The following designs cover the above:- Lec's 5482, 5485, 5489, 5492, 5503/4/5, 5512, 5534, 5538/9, 5541, 5543, 5546, 5550, 5552, 5555, 5557, 5558, 5561, 5566, 5569, 5570/1, 5575, 5580, 5582, 5590, 5596, 5598, 5609, 5613, 5616, 5620. ENGINE CONTROLS. To suit new engine unit as above. Lec.5619 etc. EXHAUST FITTINGS. To suit 4 port cylinder head. Lec.5575. RADIATOR. Revised cheapened design. N.Sch's 5069, 5077, 5097. BONNET. As already instructed and fitted to first chassis. L.O.P. EW.755/6. STARTING HANDLE. To suit revised engine. Lec's 5563, 5576, 5584. UNDERSHEETS. As first chassis but with modifications to suit new engine. Vertical and simplified engine guards may be used depending upon results of experimental tests. Recommendations of Experimental Department as result of tests are required on this item. | ||