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).
Results of gearbox testing under various conditions and with different lubricants.
| Identifier | ExFiles\Box 112\2\ scan0092 | |
| Date | 3rd June 1938 | |
| -2- Rm{William Robotham - Chief Engineer}/Gry{Shadwell Grylls}2/R.E3.6.38. Lubricant { The running consisted at full throttle 2000 rpm of Hi-Press { 1 hour on top gear. { 150 hours " overdrive. ( 30 " " 2nd { This was followed by { 5 hours on 1st speed at 2nd speed torque ( 1 hour on " " full throttle and lastly ½ hour on 1st speed full throttle using a vis 30 engine oil as lubricant. This test represents what the P.III box will now do and considerably more than the early P.III boxes can stand. The test was interrupted by occasional axle and prop shaft troubles which are receiving separate investigation. It is interesting that Leylands standard axle and gearbox test is 100 hours on 1st speed, on engine oil. The only failure caused by the dynamometer running was the 1st motion shaft bearing. The 1st speed teeth although damaged were no worse than usual. The first road run on the other gearbox fitted to 1.B.50 provided the following information:- 1st speed - too noisy, stays in gear both drive and over-run. 2nd - " ", comes out on over-run. overdrive - " " Reverse - very noisy, bronze bush seized. Selector springs gave 4 lbs on the lever knob. Dealing first with reverse gear, a flat on the shaft to distribute oil from the oil hole did not prevent seizure. When the bush was white-metalled and given .0035 clearance it did not seize after a very long climb in reverse. This has been repeated on the other box. It was then found when the seizure was overcome that reverse worked out under load, a 14 lb (measured at the knob, selector spring being required to keep it in. A slanting reverse shaft to Ph.232 reduced the 14 lbs to 9 lbs, but the noise on over-run was impossible. | ||