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).
Engine and chassis issues and modifications over thousands of miles of testing.
| Identifier | ExFiles\Box 101\2\ scan0042 | |
| Date | 20th July 1936 guessed | |
| (2) Hesitation on pick-up which had been blamed on the carburetter was found to be due to flash-over in the distributor causing misfiring at the sparking plugs. This was overcome temporarily by cleaning the plugs & setting the points at .016". A modified distributor with larger flash-over distances, together with a Phantom III type coil & ballast resistance, was fitted at 15.000 miles, & no more misfiring from this cause was experienced. At 19.500 miles, we had trouble with short circuiting of the ignition wires in the metal tube. The rubber insulation had failed. This is being experienced in service. A better class insulation is required, or a non-metallic conduit for the wires. Petrol pump failure due to loose diaphrams was experienced. As this coincided with hot weather conditions, we were led to suspect vapour-locks, but no further failure of the petrol supply occurred after the pumps had been put in order. The carbon deposit in the cylinder heads at the conclusion of the mileage was somewhat excessive. We experienced considerable accumulation of oil in the air silencer & consequent oil leaks from this unit. Running was resumed with the breather pipe from the valve rocker cover to the air silencer removed, and during 3.550 miles no ill effects were observed. The engine started easily both when cold and hot. It was found that slow running and tick-over were very much smoother at high altitudes; the loss of effective pull at 5.000 ft. was about 15-20%. At 22.000 miles, oil pressure fell off 5-8 lbs/sq." and was found to be due to dirt in the oil pressure relief valve, pressure returned to normal on rectifying the trouble. Play developed in the bushes of the fore and aft stay under the O.S. front engine mounting, and a rattle was occasionally heard when the clutch was engaged. This trouble was aggravated by seized propellor SHAFT splines, and no rattle was heard after they were released. The push rods had rubbed where they pass through the gasket and some of them had worn at this point. TORQUE REACTION DAMPERS. LOP E.60774. Complete to above LOP - Standard Production. During the 10.000 miles in England, we found it necessary to enlarge the holes in the centre plate of each damper in order to stop the centre bolts from fouling both top and bottom of the hole and producing a series of objectionable thumps on bad roads. New centre plates were fitted when the engine units were changed over. We found that on the French road surfaces the trouble was so bad as to buckle the damper arms. The holes in the new centre plates were enlarged to an oval shape 1.5" high by 1" wide, and no further trouble has been experienced. Several cars have been found in service with damper arms damaged D/O to note that these figures are essential to prevent knocks under bad road conditions. Handwritten notes: Top left: "Wst. What are we sending out to the car? What about Dodds' car and Specte coil." Bottom left: "Wym.{G. Harold Whyman - Experimental Manager} See that drawings are at once altered accordingly. 6-B-IV also. Rm.{William Robotham - Chief Engineer} O.K. [signature]" | ||