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).
Steering, clutch, piston, pinking, and vibration issues and developments.
| Identifier | ExFiles\Box 91\1\ scan0213 | |
| Date | 22th January 1936 guessed | |
| (2) cones, we should like to know what result has been obtained with ground cones or screwed cones, as these aim at providing an easy bedding. (5) Steering. The trouble we have had up to the moment with pre-loaded steering boxes as experienced on 21-G-IV is the difficulty of retaining oil in the box. This, however, has not been reported on 35-EX, and we should like to know if this steering box still remains oil tight. Clutch. We are looking into the question of reducing the clutch pedal pressure. (7) Pistons and Overoiling. Pistons ground to a form reproducing normal clearances at bottom of stroke so far do not show cold knock at 5,000 miles, and we anticipate they will remain satisfactory to the end of the test contemplated. This is with the short liners suitable for marine type connecting rods. We have now demonstrated that we can use longer gashed liners giving 2.3" piston control at bottom end which is .3" longer than present 20/25. Sets of these liners are instructed for test and for Mx.{John H Maddocks - Chief Proving Officer} to run his next development. Pinking. Pinking was not noticed on the early Phantom III's and comparing with Bentley which has the same type of head the present Phantom III's pink more than we should expect with a compression ratio of 6 to 1 as compared with 6.4 on the standard Bentley. We are issuing a simple scheme which will make the adjustment and synchronising of the timing much easier. We are also proposing to try some cylinder heads with alternative machining. (9) Vibration on the over-run. This is a matter for experimenting with different thicknesses of flywheel web and rim weight but we agree it is better to return to the original design if the Stromberg carburetter slow running standard turns out as well as it promises. | ||