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).
Vehicle performance characteristics including braking, engine timing, suspension, and steering.
| Identifier | Morton\M4.1\ img008 | |
| Date | 16th December 1920 guessed | |
| Contd. -2- Brakes - No jaggers. Foot brake - good but spongy. Side brake - very poor. Distance to pull up at ( clutch out - brake Foot brake Side brake. hard on) 20 M.P.H. 35 ft. 83 ft. 30 M.P.H. 84 ft. 238 ft. 40 M.P.H. 112 ft. 668 ft. Engine Valve Timing. I.O. 12º B.T.D.C. ) I.C. 70º P.B.D.C. ) .002" clearance. E.O. 26º B.B.D.C. ) E.C. 27º P.T.D.C. ) Bore of cylinder. 3¼" - Stroke 5¼" Valve Lift. Inlet .434" Exhaust .443" dia. of port 1.843" in. Compression. No.5 78 lbs. No.3 77 lbs. Cu. capacity 164 cu. ins. Vacuum in Induction Line. Springing. Rear - two elliptic springs across rear attached to brake. Front- Two elliptic springs front axle, fastened front of centre. 4 Hartford Shock Absorbers fitted - 2 front and 2 rear. working crossways. Friction on rear shock absorbers - 21 lbs. - fraction by steel and wood. Tests over bump on road - 20 M.P.H. Car holds road. 30 M.P.H. " " " 40 M.P.H. " " " 45 M.P.H. " leaves road and throws passengers. Without shock absorbers car does not hold road so well but is more flexible over granite roads - front springing bad. Ignition. Delco coil only - Timing fully retarded 10º P.T.D.C Advanced 17º B.T.D.C. auto:Governor. Full advanced on Goven: 42º B.T.D.C. Order of firing 1, 5, 3, 6, 2, 4. Steering. Reversible - not self-centering. Road shock on steering wheel very bad - no wobbles. Friction on pivots - 8 lbs. required first initial pull from centre. | ||