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).
Specification comparison sheet for Packard Super Eight and Packard Twelve models.
| Identifier | ExFiles\Box 127\1\ scan0216 | |
| Date | 9th May 1935 guessed | |
| -2- | | Packard Super Eight Model 1203-1204-1205 | Packard Twelve Model 1207-1208 | |---|---|---| | Valve seat angle | 45º | 45º | | Valve Spring | Packard-Double | Packard-Single | | Valve spring load - closed | 73 at 3.1/16 | 70 at 2.7/32 | | Exhaust pipe diameter | 2 1/4 | 2 3/4 | | Muffler size - overall length | 45 | 51 | | Muffler size - dia. | 5 1/2 and 7" | 5 1/2 and 7" | FRONT END DRIVE: | | | | |---|---|---| | Gear cover | Steel stamping | Aluminium casting | | Type of Drive | Silent chain, adjustable | Silent chain | | Make | Morse No.1866 | Morse No.1866 | | Length | 32" - 64 links | 28" - 56 links | | Pitch | .500 | .500 | | Number camshaft bearings | 8 | 4 | PISTON: | | | | |---|---|---| | Piston material | Alum. alloy with strut | Alum. alloy with strut | | Clearance at skirt | .0015 | .0015 | | Piston pin diameter | 7/8 | 7/8 | | Piston pin length | 3.3/64 | 2.63/64 | | Piston pin type | Floating | Floating | | Number of rings per piston | Four | Four | | Number of oil rings | One | One | | ||