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).
Graph showing the effect of valve timing overlap on power for a single cylinder engine test.
| Identifier | ExFiles\Box 133\2\ scan0124 | |
| Date | 1st November 1934 guessed | |
| BENTLEY SINGLE CYLINDER TESTS SHEET 5 EFFECT ON POWER OF VALVE TIMING OVERLAP (CLOSE-CENTRES HEAD) "CLOSE-CENTRES" CYLINDER HEAD (L.E.C4100) COMPRESSION RATIO - 6.35 INLET VALVE = 1.500 DIA., EXHAUST VALVE = 1.400 DIA INLET PORT = 1.500 DIA., & VALVE GUIDE BOSS REMOVED AEROLITE PISTON ZENITH TRIPLE DIFFUSER CARBURETTOR (32% CHOKE) OPEN EXHAUST FUEL DTD 224. BRAKE HORSE POWER B.M.E.P. (LBS/SQ.IN.) R.P.M TABLE DATA: CURVE | TIMING | I.O | I.C | E.O | E.C | OVERLAP 1. | NORMAL BENTLEY | 4°E | 51°L | 51°E | 7°L | 11° 2. | | 1°L | 51°L | 51°E | 1°L | 0° 3. | BEST AT 3000. | 10°E | 37°L | 53°E | 2°L | 12° 4. | | 4°E | 37°L | 53°E | 4°E | 0° | ||