Performance curves for a B.7 Unit engine with Aerolite Pistons, comparing different valve timings and cylinder configurations.
| Identifier | ExFiles\Box 82\2\ scan0200 | |
| Date | 15th September 1934 | |
| B.V.48 B.7 UNIT. SPECIFICATION:- R.H.C./W.S.C. 10/EP {G. Eric Platford - Chief Quality Engineer} 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" (PISTON CLEARANCE = .0025 TO .003) 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" (PISTON CLEARANCE = .0045 TO .005) ④ NEW STANDARD BORE CYLINDER BLOCK FITTED, NEW CAM-WHEEL FITTED GIVING VALVE TIMING "C". (PISTON CLEARANCE = .0025 TO .003) ALL CURVES TAKEN OPEN EXHAUST & WITHOUT AIR SILENCER AXIS LABELS: B.H.P., R.P.M., B.M.E.P. (LB/SQ.") "C" TIMING DIAGRAM: T.D.C., 2°, 75°, INL., EXH., 52°, 47° VALVE TIMING (.020 CLEARANCE) "A" TIMING DIAGRAM: T.D.C., 6°, 3°, EXH., INL., 52°, 47° "B" TIMING DIAGRAM: T.D.C., 11°, INL., EXH., 54°, 46° HANDWRITTEN NOTE: R.H.C. / W.S.C. 18.9.34 | ||
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).