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).
Component wear and performance issues, focusing on controls and clutch systems.
| Identifier | ExFiles\Box 71\4\ scan0104 | |
| Date | 31th March 1925 guessed | |
| - 2 - present coupling. Oil pressure varies considerably - could not be remedied by making sure that relief valves were O.K. Probably a bad pump. Spring loaded fan satisfactory - gave no trouble. Fan very immune from booms. Engine good for vibrations. There is rather a bad period at 10 to 12 m.p.h., otherwise it is very smooth. Front engine suspension soon gave way. New stiffer suspension fitted after 5,000 miles. This, also, is giving way in the same manner as the old one. Big end bearings, after 5,000 miles, were in very good condition, with the exception of No. 3, the metal in which had picked up badly, probably owing to dirt. Cylinder bores were in very good condition. Throttle governor functions O.K. This gave no trouble. CONTROLS. The following controls have worn excessively, and require designing on stouter lines :- 1. Bracket on rear cylinder block that carries bell crank lever for magneto ignition advance and retard. 2. Step-aside countershaft (accelerator pedal control) from frame side member to engine crankcase, very sloppy in its bearings. This gives a considerable amount of accelerator pedal movement, with no corresponding throttle movement. It also tends to prevent the throttle from closing properly, as the return spring for this set of controls is on the accelerator pedal. Consequently the throttle end of the control does not return to its original new position, being short of this by the amount of slack in the controls. We have had to shorten the final control rod to accomodate this slack, and by so doing we have lost a certain amount of full throttle opening. 3. Ball end fitted to the lever coming from the ignition relay servo has worked loose in its socket. This is normally rivetted in. 4. The shaft that carries the throttle governor cam has become very sloppy in its bearings. This allows the cam to drop slightly, and so prevents the throttle from closing fully. We have had to file away the cam slightly to accomodate this wear. All other ignition and throttle controls are in quite good condition. 5. Clutch pedal has worn very sloppy on the pedal shaft. CLUTCH. Clutch trunnion sleeve became very hot and started seizing up on its shaft. This was probably due to too little clearance being allowed in clutch spring actuating levers. We find the minimum allowable clearance for these levers, when cold, is .040". If any less is allowed there is danger of there being no clearance at all when the clutch is hot. | ||