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).
Performance graph for a B.7 Unit engine, showing BHP and BMEP against RPM for different valve timings and cylinder bore dimensions.
| Identifier | ExFiles\Box 82\4\ scan0051 | |
| Date | 15th September 1934 | |
| B.V.48 B.7 UNIT. SPECIFICATION:- R.H.C./W.S.C. 10/GP 15.9.34. AEROLITE PISTONS ("E" SET) A.122 ALLOY. ① 6.95:1 COMP. RATIO 1.500 DIA. INLET 1.200 EXHAUST VALVES. STANDARD CYLINDER BLOCK 3.250 DIA. VALVE TIMING "A" ② AS ① BUT WITH VALVE TIMING "B" ③ AS PREVIOUS CURVES BUT WITH CYLINDER BLOCK .002 OVER STANDARD DIMENSION (i.e. 3.252 DIA.) VALVE TIMING "B" ALL CURVES TAKEN OPEN EXHAUST & WITHOUT AIR SILENCER B.H.P. B.M.E.P. (LB/SQ IN) R.P.M. VALVE TIMING (.020 CLEARANCE) "A" TIMING T.D.C. 6° 3° EXH INL 47° "B" TIMING T.D.C. 11° EXH INL 52° 54° 46° R/W 18.9.34 | ||