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).
The performance and recommended modifications for the carburettor, air silencer, camshaft, and water pump.
| Identifier | ExFiles\Box 108\3\ scan0230 | |
| Date | 9th May 1938 | |
| -7- Carburetter Nov.GM.1099. Carburation was good, free from flat spots throughout the range. Starting, slow running and idling remained good and the engine was exceptionally good for not stalling, such as after heavy braking to a standstill. The strengthened choke spring was not sufficient to overcome the stiffness which developed in the spindle bearings. These were counter-bored to reduce their effective length when the car returned to Derby. The choke then worked perfectly freely with the standard return spring. This modification is recommended for service and production. Carburetter Air silencer LOP.EM.868. The front end worked loose in the main body, causing a rattle. A modification was called for after the last test and should be used for production. Camshaft LOP.EM.1421. EX.29816 Camshaft rattle elimination. This gave no trouble and has been shown on other Wraith engines to stop rattle. Water Pump LOP.EM.1448. No trouble was experienced and the gland remained free from leaks. A squeak of brief duration was heard on occasions when starting from cold. This appears to come from the thrust peg. A stainless steel plug is now being tried to overcome this. | ||