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).
Engine component specifications and analyzing a loss in power performance.
| Identifier | ExFiles\Box 111\3\ scan0082 | |
| Date | 27th April 1939 | |
| -2- (6) Valves - Exhaust - Nos. 1, 2 and 3 sodium filled. - Nos. 4, 5 and 6 solid stems. Inlet - Motor Component produced. (7) Connecting rod little end bushes - Nos. 1, 2 and 3 'Karo' Bronze. Nos. 4, 5 and 6 Vandervell "Clevite 10". (8) Original short duration camshaft (S/ZN) having latest distribution drive tooth form to improve wear. (9) Continental B.V. induction system mocked up to ports by Adaptor flanges, i.e. 1 3/4" manifold, 2 - 1 3/4 S.U. carbs. POWER. Attached herewith is a power curve of the unit showing a maximum power of 125 BHP, open exhaust and a maximum MEP. of 126 lbs/sq.in. at 2000 R.P.M. It will no doubt be wondered why this unit is down in performance as compared with 127 BHP. and 131 lbs/sq. in. MEP. given in our report Rm.{William Robotham - Chief Engineer}1/MH.{M. Huckerby}9.2.39. This is attributed to the following reasons, which we consider would collectively make up this loss. (1) R.R. split skirt pistons in standard position, i.e. .030 down the block compared with Aerolite flush top pistons. Increased friction of the former and improved by flush top pistons, both through 6.2 to 6.4 compression ratio and its effect on combustion chamber characteristics as previously proved. (2) General tightness of the AC.9 big end bearings and local hard spots on the main bearings. | ||