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 power output of a 3 1/2 Litre Bentley B.4 Unit engine under two different test configurations.
| Identifier | ExFiles\Box 86\1\ scan0118 | |
| Date | 31th January 1935 | |
| 3 1/2 LITRE BENTLEY POWER OUTPUT B.4 UNIT. SPEC'N: CP.2 (3C/F1-39) RHC{R. H. Coverley - Production Engineer} CP.6 (BC/F1-39) ① COMP. RATIO 6.45:1 (EB 6/5) IN. VALVE 1.400 DIA. EX. " 1.300 " AEROLITE PISTONS (G4) STD. CYL. BLOCK +.002 STD. CAMSHAFT EB/085 (7.34) ② COMP. RATIO 7:1 (EB 2050) IN. VALVE 1.500 DIA. EX. " 1.200 OTHERWISE AS TEST ① OPEN EXHAUST SHELL Nọ1. FUEL CASTROL C.N. OIL K.L.G. 827 PLUGS STD. INDN. SYSTEM (NO AIR SILENCER) B.H.P B M E P R.P.M. TDC 3.6° 3° IN. Ex. 49° 50° BDC (TAPPETS .020") CTS{C. Trot Salt - Carburation} | ||