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).
Summary of specifications for the 21-G-IV model being prepared for a 10,000 miles test.
| Identifier | ExFiles\Box 101\4\ scan0032 | |
| Date | 29th April 1935 | |
| X500a To RHC.{R. H. Coverley - Production Engineer} HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/KW.29.4.35. 21-G-IV. Herewith is a summary of the present specification of 21-G-IV which is being prepared for a 10,000 miles test :- ENGINE UNIT. (1) Cylinder head with 2 KE.965 valves, 2 Silichrome valves and 2 stellited Silichrome valves. (2) New cylinder block with 20/25 pistons. (3) New main bearings. (4) New lead bronze big end bearings without shim, a hole in the top of connecting rod for gudgeon pin lubrication, Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}13/KW.18.4.35. (5) Drilled connecting rods with lubrication hole for piston lubrication, and a groove at the back of the bearing. (6) Improved crankcase breather to LeC.4438. (7) Bentley clutch pit and bottom half in magnesium. (8) Geared starter motor. (9) Clutch plate as B-10, Terraplane spring centre strengthened, back plate to have no movement, Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}2/KW.16.4.35. (10) Air cooled dynamo CHASSIS. (11) Wycliffe Cast Iron drums. (1) Isolated change speed lever, N.Sch.4474. (2) Latest type water excluders, N.Sch.4458. (3) 17" rims front and rear, N.Sch.4426/4429/4432/4433. (4) Baffle tank unit and green light scheme, HS{Lord Ernest Hives - Chair}/Bwg.{J. C. Bowring}14/KW.9.4.35. (5) R.R. Marles steering with Controls (6) Hypoid rear axle | ||