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).
Initial test results and identified issues with the Wraith engine unit.
| Identifier | ExFiles\Box 6\6\ 06-page242 | |
| Date | 28th June 1937 | |
| Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} Hu. c. to H.{Arthur M. Hanbury - Head Complaints} c. to Hy.{Tom Haldenby - Plant Engineer} c. to Ds. 600 Rm{William Robotham - Chief Engineer}4/R.28.6.37. WRAITH ENGINE UNIT. The second engine unit which has been prepared for the Wraith car, which is going to run the first 15,000 miles' test, was passed off the bed this week-end. The bottom tappets which originally gave trouble with scoring are now satisfactory. The solution appears to have been running them in on an extreme pressure oil, ensuring that they turn round, crowning the face of the tappet, and using the Chevrolet type push rod location. Troubles which are in evidence on this engine, and with which we have not yet had time to deal, are:- (1) It was noticeable that the half crankshaft period was more violent than on a standard engine and could not adequately be dealt with by the ordinary spring drive. (2) Oil consumption is so far very high. (3) The heat to the oil is greater than on a standard engine. (4) So far the timing gears have not shown any indication that they will be easy to get quiet. We are trying increased helix angle, and altering the acoustic properties of the cover. (5) The valve gear is very noisy. This will mean a modification to the camshaft. These faults were all present on the first engine so that they may be considered as being representative of the type. Rm.{William Robotham - Chief Engineer} | ||