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).
List of modifications to a Straight Eight Wraith engine to increase displacement and meet production requirements.
| Identifier | ExFiles\Box 97\1\ scan0053 | |
| Date | 8th June 1937 | |
| B. III 200B 400 TO MAKE STRAIGHT EIGHT WRAITH ENGINE A 300 cu. ins. DISPLACEMENT OR A % INCREASE OF 15%. MODS NECESSARY TO MAKE ENGINE SUITABLE FOR TO-DAY'S PRODUCTION REQUIREMENTS. (1) Cylinder studs moved out .125 (2) Valve Gear modified to latest (3) Crankshaft can be brought up to 2¾" dia. without moving studs. (4) Cylinder walls would have to go out. (5) Tappet Chamber modified to take Wraith Valve Gear. (6) Cyl. Head brought into line with Wraith, Sparking plug between push rods. THE VARIOUS DIMENSIONS THAT THE ENGINE COULD BE ARE AS FOLLOWS:- 3" Bore 255 cu. ins. 3⅛" " 276 " " 3¼" " 298 " " THE CRANKCASE IN CAST IRON CANNOT BE CONSIDERED ABSURDLY HEAVY AS IT FOLLOWS, OLDS, WILLYS, CHRYSLER & BUICK PRACTICE. WITH ALUM. CRANKCASE AND CAST IRON HEAD 8 CYL. 5 LBS HEAVIER THAN THE BENTLEY. ALL CAST IRON 120 lbs HEAVIER THAN THE BENTLEY. WILL TAKE THE GRAHAM BLOWER AND THEIR WORM DRIVE. | ||