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 sheet detailing dimensions, materials, and other data for various automobile components.
| Identifier | ExFiles\Box 50\3\ Scan053 | |
| Date | 6th January 1921 | |
| 8 AUTOMOTIVE INDUSTRIES THE AUTOMOBILE January 6, 1921 Piston Pins Outside diameter .................... .873 Inside diameter ........ 9/16 to 11/16 Material ..No. 1020 S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} steel, annealed and case hardened Connecting Rod Length center to center ............ 8-1/2 Diameter cap bolts .................... 5/16 Thickness of web ..................... 7/32 Thickness of flange ................... 5/8 Material ........................ D. {John DeLooze - Company Secretary} F. {Mr Friese} steel Crankshaft Front b'r'ng...1-3/4 dia. x 2-31/64 long Second b'r'ng..2-1/4 dia. x 2-3/8 long Third bearing...2-3/8 by 3-1/8 long Crankpin ......2-1/4 dia. by 1-1/2 long Cr {Mr Cra???ster / Mr Chichester} 's sec. short crank arm..2-3/4x1-7/8 Diameter flywheel flange .......... 4-7/8 Thickness flywheel flange ........... 3/8 Material ..D. F. {Mr Friese} steel .40 to .50 carbon Crankshaft Bearings Thickness of shell .................... 3/32 Material ............. Babbitt-bronze back Camshaft Diameter ............................. 1-1/8 Frnt bearing..2-1/8 dia. by 1-1/4 long Second bearing ........... 1-3/4 dia. by 1-1/2 long Third bearing .......1 dia. by 2 long Diameter gear flange ................... 3 Width of cam face .................... 5/8 Radius folower circle ............. .8437 Material ..D. F. {Mr Friese} steel No. 1020 S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} Material camshaft bearing Phosphor bronze S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} No. 26 Valves Clear diameter ........................ 1-5/8 Diameter of valve stem... .310 to .311 Lift ..................................... .415 Material ...............E. W. P. alloy Valve Springs Total load—main spring...45 to 50 lb. Total load aux. springs...23 to 28 lb. Material ....... Round steel spring wire Timing Gears Pitch ................................... 10 Width of face ........................ 1-1/4 Number of teeth in crankshaft gear..33 Material of crankshaft gear... C. R. {Sir Henry Royce} S. Number of teeth camshaft gear.......66 Material camshaft gear ........C. I. Flywheel Pitch diameter ................... 15.750 Width .......................... 3-9/32 Thickness of web ..................... 1/2 Teeth .............. 126—8-10 pitch Face ............................... 1-1/8 Material ....................... Semi-steel Crankcase Thickness side walls ................ 3/16 Thickness top ........................ 3/16 Thickness legs ....................... 3/16 Thickness ends ........................ 1/4 Material ...................... Cast iron Cast integral with cylinder block Water Pump Diameter of paddle....3.994 to 3.996 Width of paddle ........... .499 to .501 Number of blades ..................... 10 Material ...................... Red brass Radiator Area front .................. .375 sq. in. Thickness................2-3/4 in. core Capacity water system .......17 qt. Carbureter Make ............................. Rayfield Size ...................1-1/2 horizontal Clutch and Transmission Clutch Diameter of disk .............. 8-5/8 in. Number of disks ....................... 10 Width of facing .................... 1-1/16 Thickness of facing ................. 1/8 Material facing ............. Thermoid Spring pressure ..........240 to 270 lb. Transmission Gears Const. mesh primary ......... 15 teeth Const. mesh secondary ...... 27 teeth Low speed primary .......... 27 teeth Low speed secondary ........ 15 teeth Second speed primary ....... 20 teeth Second speed secondary ..... 22 teeth High speed, telescoping .... 15 teeth Reverse primary ............ 12 teeth Reverse idler ................ 17 teeth Pitch of gears ...................... 6-8 Width of gear face ................. 3/4 Material of gears....Oil hardened steel Reduction in Transmission Reverse ...................... 4.05 to 1 Low .......................... 3.24 to 1 Second ....................... 1.636 to 1 High ............................. Direct Total Reduction Reverse ..................... 18.73 to 1 Low ......................... 14.98 to 1 Second ....................... 7.56 to 1 High ......................... 4.625 to 1 Shafts Diameter primary shaft (six spline) .................................... 1.475 Material primary shaft S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} steel No. 1045 Diameter section secondary shaft .................................... 1.188 Material secondary shaft S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} steel No. 1045 Bearings Primary drive shaft, front No. 1209 ball bearing Primary drive shaft, rear No. 306 ball bearing D. {John DeLooze - Company Secretary} R. {Sir Henry Royce} Secondary shaft, front Hyatt roller bearing Secondary shaft, rear Hyatt roller bearing Reverse shaft ...... Bronze bushing Rear System Axle Housing Thickness center section ............ 3/8 Diameter center section .......... 12-7/8 Thickness tubes ..................... 3/16 Diameter tubes ................. 2-41/64 Distance between spring centers..41-1/2 Material of housing......Pressed steel Shafts Diameter of propeller shaft .... 1-3/4 Material ................ Nickel steel tube Diameter of live axles ......... 1-3/8 Material .......No. 3125 S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} steel Driving Pinion Pitch ................................ 3.47 Face .............................. 1-5/16 Number of teeth ....................... 8 Material ....................Steel forging Ring Gear Pitch ................................ 3.47 Face .............................. 1-5/16 Number of teeth ...................... 37 Ratio ......................... 4.625 to 1 Material ....................Steel forging Differential Pinions Pitch ................................. 5.7 Face ............................... 11/16 Number of teeth ...................... 10 Material ........................... Steel Differential Gear Pitch ................................. 5.7 Face ............................... 11/16 Number of teeth ...................... 18 Material ........................... Steel Brakes Diameter of service (foot) brakes..16 Width of service brakes ............ 2 Diameter emergency (hand) brake...8 Width emergency brake ............ 2 Material lining..Compressed Thermoid Material brake drum....Pressed steel Bearings Hubs ..........No. 310 S. Row Ball Differential, r. {Sir Henry Royce} and l...No. 210 R. {Sir Henry Royce} & T. Driving pinion, rear....No. 305 Radial Driving pinion, front..No. 406 R. {Sir Henry Royce} D. {John DeLooze - Company Secretary} T. Hubs Diameter flange .................... 8-1/4 Thickness flange ................... 1/4 Material flange ............. Mall. iron Diameter bolt circle ............. 6-3/4 Number of bolts ....................... 6 Diameter of bolts ................. 11/16 Front Axle Front Axle Forging Depth of center web ............... 2-1/4 Width of flanges .................. 1-1/2 Thickness of web .................... 3/16 Distance between spring centers..28-1/2 Distance c. to c. king pins......51-3/4 Material ..................... D. {John DeLooze - Company Secretary} F. {Mr Friese} steel Steering Knuckles Diameter of spindle—maximum..2-1/4 minimum.. .786 Material ..................... D. {John DeLooze - Company Secretary} F. {Mr Friese} steel King Pin Length of king pin ............... 6-29 Diameter of king pin ................ 3/4 Material .........No. 1020 S. A. {Mr Adams} E. {Mr Elliott - Chief Engineer} steel Front Wheel Bearings Inside hub bearings ....No. 308D. R. {Sir Henry Royce} Outside hub bearing ..No. 304 S. R. {Sir Henry Royce} Front Wheel Hub Diameter of flange................ 7-1/2 Thickness of flange............... 1/4 Material of flange.......... Mall. Iron Diameter bolt circle.................6 Number of bolts.....................10 Diameter of bolts..................3/8 Frame, Springs, Etc. Side Rails Depth of channel.................. 7-3/4 Width of flanges.............1-1/2 to 3 Thickness of stock..................1/8 Overall width (of frame) 23-3/8 to 45-1/2 How fastened .............. Hot riveted Material ................Pressed steel Cross Members Number of cross members...............3 Thickness of stock..................1/8 Material..................Pressed steel Steering Gear Diameter wheel......................18 Diameter steering shaft..........1-1/8 Number of teeth in gear.............24 Pitch................................ 8 Length of steering arm............7-1/2 Springs Length of front spring................34 Width of front spring.................2 Number of leaves in front spring......7 Length of rear spring.................56 Width of rear spring..................2 Number of leaves in rear spring......10 Material—Front, Vanadium steel; Rear, Carbon steel Wheels Front wheel (tire size)...34 by 4, cord Number of spokes in front wheel...10 Width of spokes in front wheel..1-3/8 Rear wheel (tire size)....34 by 4 cord Number of spokes in rear wheel....12 Width of spokes in rear wheel..1-3/8 Fenders Width of front fenders..............10 Width of rear fenders...............10 Thickness of material...............1/8 No. 20 U. S. G. {Mr Griffiths - Chief Accountant / Mr Gnapp} (.038) Material..................Pressed steel Gasoline Tank Where located .....................Rear Main supply ....................17 gal. Thickness of material.......No. 20 gage Material..................Pressed steel | ||