Performance graph for a 20/25 HP engine, Unit C.9, with a J.L. head, comparing different configurations.
| Identifier | ExFiles\Box 31\4\ Scan239 | |
| Date | 7th January 1932 | |
| UNIT C.9 (J.L. HEAD) 20/25 H.P. 7-1-32 RM {William Robotham - Chief Engineer} 73 COMP. RATIO 6.3:1 E.57717 (M2°) CAMSHAFT. TWO EXHAUST CAMS. ① 2 .1625 S.U. CARBS ( .062 RESTD. BALANCE ) ② 2 .1875 S.U. CARBS. ( ③ AS ① WITH .062 PLATE REMOVED B.H.P. R.P.M. B.M.E.P. INDN. PIPE. DEPRn "Hg" TAPPETS AT .010 47° 44° EX 46¼° C.T.S. | ||
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).