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).
7,500-mile report on the IV-34 engine unit, detailing performance issues and component conditions.
| Identifier | ExFiles\Box 5a\2\ 02-page044 | |
| Date | 6th July 1908 guessed | |
| To: Hs.{Lord Ernest Hives - Chair} From: G.T.S. Hôtel de France, Châteauroux, Indre. REPORT ON 14-34 7,500 MILES ENGINE IV-34 UNIT. We have had trouble with the engine due to the high compression. Firstly we could not run for any distance without the plugs pre-igniting to such an extent that the speed of the car was brought down from 60 to 40 M.P.H. We fitted Lodge type Aero A-40 Plugs which overcame the pre-ignitions, but they will not start the engine up when they are cold. To do so, we find that it is necessary to fit a much smaller resistance in series with the coil. At approximately 2,000 miles, we had a serious loss of oil. The oil we found was coming out at the front end of the engine. This was leaking from the engine timing cover through the clearance for the fan pulley. The trouble was located to a high crankcase pressure, and to continue running without loss of oil, it was necessary to take off the breather cap to relieve the pressure in the crankcase. The power of the engine deteriorated somewhat due to the loss of compression in N° 1 cylinder. Crankshaft periods became very noticeable towards the end of the mileage, and the engine became rough generally. We got bad detonations during the latter part of the mileage. At the finish of the 7500 miles, the engine was dismantled. CYLINDERS TO L.O.P. SS{S. Smith}5045. TURBULENT HEAD S/C. to Lec's 2571/3/4. RECS S/C & 2569. These when examined were in a very good condition and had been well and evenly lubricated. CYLINDER HEAD. There was a good coating of carbon in the cylinder head which accounts for the detonations. The casting did not show any deteriorations and we have not noticed any faults with cooling of the head. The gasket had been making a good joint. VALVES AND FITTINGS TO LOP. SS{S. Smith}5049 LEC's 2563 2565/6. DURAL PUSH RODS FITTED. We have had very little trouble with the valves, the clearance has remained fairly constant. These were set to .004" inlet and .006" exhaust with engine cold. When examined we found that N° 7 valve had picked up the brass from the seat slightly, the others were in perfect condition, the valve guides and stems had been well lubricated and were in a very good condition. No flaws or otherwise could be discerned in the valve springs. The Dural push rods and the steel tips were in good condition, the spherical ends showed very little signs of wear. There was one push rod that had been fouling where it passes through the cylinder head, this was only slightly marked. The condition of the rocker arms was good, lubrication of the bearing surfaces was ample and no wear could be discerned. We have not noticed any objectionable noise when warming up from dead cold from the tappets due to uneven expansion. | ||