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).
Vehicle 19.G.IV at 8,000 miles, detailing engine, piston, and valve performance.
| Identifier | ExFiles\Box 5a\3\ 03-page030 | |
| Date | 11th September 1931 | |
| To Hs.{Lord Ernest Hives - Chair} From G.S.H. Hotel de France, Chateauroux, FRANCE. 11/9/31. REPORT ON 19.G.IV. AT 8,000 MILES. ENGINE UNIT NO.C.10. The engine at the beginning of the mileage was inclined to be on the rough side, but with continued running it is now considered to be a very smooth engine. The torque reaction effect was rather pronounced at the start, but by reducing the poundage of the torque reaction dampers from 9 - 4 lbs friction load, the torque reaction effect is very small and equal to any standard production car. The diamond mounting of the engine has reduced periods of booms in the body. We have had one feature with the mounting that caused trouble, this was a knock or rattle which was caused by the fabric becoming dry in the f.{Mr Friese} bracket supporting the gearbox. After soaking the fabric in oil this has not again occurred. Examination of the front mounting has not shown any defects. We may point out with this mounting, it is impossible to take down the front engine case to attend to the slipper wheel or timing gears, without first removing the front crossmember and the crossmember for the radiator suspension. We noted that an extra clearance of .5" for the timing case to be removed would overcome this trouble. To overcome slight thuds of the engine which at first was reported, we reduced the poundage of the slipper wheel from 9 to 7 lbs. A slight engine gear rattle was not sufficient to warrant any change being made. PISTONS to LOP.E.35804. Up to the present mileage we have had no definite sign of piston knocks either hot or cold. There has been no sign of overoiling. VALVES & FITTINGS to LOP.E.35577. We fitted upon arrival here a set of 30% stronger valve springs as issued by the Expl. Dept. to overcome valves leaving their seats upon accelerating in 3rd. gear. We have not noted any serious defects from the fitting of same, they have been free from any periods of swishing and are generally quiet. We have had three cases of valves losing their clearance - i.e. Nos 2, 4, 5, exhaust valves respectively. We find that for continental running that a clearance of .006 is necessary for exhaust valves and .004 for inlet valves. In the above stated valves .003 clearance had been lost. No other troubles have been experienced at this mileage. | ||