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).
Mechanical specifications comparison sheet for Packard Super Eight and Packard Twelve 12th series models.
| Identifier | ExFiles\Box 127\1\ scan0215 | |
| Date | 9th May 1935 guessed | |
| x431 MECHANICAL SPECIFICATIONS. Extracts from Packard Service Information - 12th Series. Packard Super Eight Model 1203-1204-1205 Packard Twelve Model 1207-1208. ENGINE: Firing Order: 1-6-2-5-8-3-7-4. | 1R-6L-5R-2L-3R-4L-6R-1L-2R-5L-4R-3L. Bore: 3½ | 3 7/16. Stroke: 5 | 4½ Piston displacement: 384.8 cu.in. | 473 cu.in. Compression ratio - Std.: 6.3 alum.head | 6.4 alum. head " " optional.: 6.0 " " | 6.0 " " VALVES: Valve lift: .358 | 5/16 Valve arrangement: L-head | Modified L-head Valve stem clearance (Inlet): .0025 | .0025 Valve stem clearance (Exhaust): .004 | .005 Valve tappet clearance (Warm Inlet): .004 | Automatic take-up Valve tappet clearance (Warm Exhaust): .006 | Automatic take-up Inlet valve opens: 30º BTDC | ATDC Inlet valve closes: 65º ALDC | 45º ALDC Exhaust valve closes: 30º ATDC | 10º ATDC Exhaust valve opens: 65º BLDC | 35º BLDC | ||