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).
Customer letter detailing engine performance issues and suggestions for chassis 117-MC.
| Identifier | ExFiles\Box 47\1\ Scan226 | |
| Date | 23th January 1926 | |
| C O P Y. SHOTTON, Telephone Chester 535. CHESTER. Telegrams :- Summers, Chester. Jan. 23rd. 1926. Dear Sirs, Ref. Chassis 117-MC. While the above car is at your Works next month for alterations to springing and steering and decarbonising of Engine, I would be glad if you would look into the following points also :- 1. The other day an exhaust valve stuck open but before I could take the cover off to identify it it closed again with a snap: This was after a high speed hill climb (on 3rd. gear) of about 3/4 mile. 2. After prolonged bursts of speed on low gear (say a mile at 58 m.p.h. on third) if the engine is switched off it will almost invariably pre-ignite and run backwards before stopping. 3. I am not convinced that the plugs you fit are the best for high revs. and prolonged full power periods. Phenomenal slow running leaves me rather cold, whereas steady full power output at 3,000 revs. or thereabouts sends a warm glow to my mechanical subconsciousness! 4. Where the engine is idling there is at times an annoying rattle somewhere in the Dynamo and Magneto drive. 5. The performance of the engine, while very pleasing and beautifully smooth, would give me even greater pleasure if the compression ratio were slightly higher and valve springs a little stronger and of course, suitable plugs fitted to cope with the inevitably higher temperatures. 6. The engine at present would appear to reach it's power curve peak at about 55 m.p.h. on third gear, i.e. about 2650 revs. Over 60 m.p.h. on third is almost unattainable on a level road even with my specially high gear ratio. Is this as it should be? It is so very little better than my old 39-TW. and surely the extra cwts. you have put into the Engine have made engine speeds of 3,000 or even 3,500 r.p.m. safe. I feel in items 5 and 6 I am treading dangerous P.T.O. ENCLOSURE No 508 CUSTSD | ||