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).
10,000-mile report on car 28-EX, detailing engine performance and flexible engine mounting tests.
| Identifier | ExFiles\Box 11\5\ 05-page164 | |
| Date | 18th September 1934 | |
| x7941 To Mr. From G.W.H. c. Wor.{Arthur Wormald - General Works Manager} S. c. EY. H.S. c. EX. HS.{Lord Ernest Hives - Chair} Hotel de France, Chateauroux. Indre. France. 18th September 1934. REPORT ON 28 - EX AT 10,000 MILES. ENGINE PH.II UNIT N° 28 E.{Mr Elliott - Chief Engineer} 84568 CYLINDER HEAD MOD. TO E.85654. The power has been good. Tests taken on the Montlhéry Track gave a maximum lap speed of 86.21 with the hydraulic adjustable rockers in action, and 86.47 MPH. with the rockers made standard. Slow running became erratic towards the latter end of the mileage through loss of compression, due to the distortion of the exhaust valve seatings, the worst being the experimental N.M.C. seatings fitted to N°s. 1, 3 and 5 cylinders. FLEXIBLE ENGINE MOUNTING INCORPORATED TO LEG. 3945 & 6. The flexible mounting of the engine at the front end caused loss of support to the frame. The moving weight of the engine also had an adverse effect upon the frame, which was the cause of unsteady steering, pronounced knocks of the wheel, unsteadiness of the front wongs and headlamps. The flexibility had also an adverse effect upon the clutch. This has been proved by fitting the standard front engine mounting and torque reaction dampers. The fitting on the front support only, brought the steering 75% steadier, lessened the movement of the wings 25% and stopped the grabbing of the clutch 80%. The fitting of the torque reaction dampers with a friction load of 35 lbs. completely cured the grabbing of the clutch, decreased wing and lamp movement a further 60%, made the steering equal to standard and no severe kick backs from the steering wheel. By making the torque reaction dampers solid, 99% of the wing movement was cured. None of these modifications made the engine feel rougher or transmitted any marked vibrations to the frame. The front engine foot rubber mounting as designed, gave the necessary damping to the engine. A softer rubber could be used, as their only use is to prevent the engine rocking over too far. With the original engine feet fitted along with the above, booms in the body were amplified and vibrations noticeable. Without any front engine feet fitted, no difference was made to the steering or engagement of the clutch, vibrations or booms. | ||