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).
Comparison of engine specifications between the Lorraine-Dietrich and the 20HP R.R. models.
| Identifier | ExFiles\Box 5a\5\ 05-page032 | |
| Date | 30th March 1927 | |
| GENERAL DESCRIPTION OF THE LORRAINE-DIETRICH ENGINE. (WITH STANDARD 20HP R.R. FIGURES FOR COMPARISON) | | LORRAINE-DIETRICH | 20 H.P. R.R. | |---|---|---| | BORE. | 75 m/m (2.95 ins) | 3.00 ins. | | STROKE. | 130 m/m (5.12 ins) | 4.50 ins. | | TOTAL SWEPT VOLUME. | 3444 c.c. | 3127 c.c. | | COMPRESSION RATIO. | 5.9 to 1 | 4.75 to 1 | | CONN. ROD/CRANK RATIO. | 3.54 | 3.53 | | RECIPROCATING WEIGHT. | 1.38 LBS. | 1.72 LBS. | | MAXIMUM B.H.P. (WITH SILENCER). | 72.5 (2750 RPM) | 50.0 (2750 RPM) | | MAXIMUM B.M.E.P. (WITH SILENCER). | 107.0 (2200 RPM) | 91.0 (1750 RPM) | | MAXIMUM COMPRESSION PRESSURE. | 132.5 (2250 RPM) | 94.3 (2250 RPM) | | MAXIMUM B.H.P. PER LITRE. (WITH SILENCER). | 21.1 | 16.0 | | MAXIMUM VALVE LIFT. (NO TAPPET CLEARANCE). | .375 in. | .340 in. | | AREA PAST VALVES (FULL LIFT). | 1.61 SQ. INS. | 1.04 SQ. INS. | | FREE AREA PAST VALVES / PISTON AREA RATIO. | .2354 | .1472 | | VALVE TIMING (.020" TAPPET CLEARANCE). | | | | INLET OPENS | 13° AFTER T.D.C. | 10° AFTER T.D.C. | | INLET CLOSES | 63° AFTER B.D.C. | 34° AFTER B.D.C. | | EXHAUST OPENS | 50° BEFORE B.D.C. | 38° BEFORE B.D.C. | | EXHAUST CLOSES | T.D.C. | 2° AFTER T.D.C. | | IGNITION ADVANCE REQUIRED AT MAXIMUM B.H.P. | 33° BEFORE T.D.C. | | | INERTIA OF FLYWHEEL | .3767 LBS FT² UNITS | .6911 LBS FT² UNITS | | CARBURETTORS. | TWO ZENITH TRIPLE. VERTICAL-HORIZONTAL TYPE, EACH FEEDING THREE CYLINDERS. NO BALANCE PIPE. | SINGLE R.R. STD. EXPANDING TYPE. | | ||