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).
The performance of Chassis 8 EX following a 10,000-mile test.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan290 | |
| Date | 10th December 1925 | |
| To: "Hs{Lord Ernest Hives - Chair}" From: G.W.Hancock. Hotel de France, Chateauroux, Indre. France. December 10th, 1925. Chassis 8 EX. Report at finish of 10,000 miles. ENGINE. The performance generally during the 10,000 miles, has been satisfactory. The filter in engine base at close of test, when dismantled, was found clean. The dirty oil has been drained out of base every 2,500 miles, and replaced with clean oil. Power. The power of the engine has been very good. We have noticed no deterioration. In fact it has given an impression of gaining power. Lubrication of cylinders. The lubrication of cylinders has kept even. Examination at finish of runs has not shewn excess of oil on cylinder walls. The standard 15 min run & plugs examined. Condition of cylinder walls. These have remained in a very good condition. There was a fair amount of carbon round the top edge. Valves & fittings. Improved lubrication to tappets to Sch.634, otherwise to L.O.P. E.72113. Improved bottom valve spring washer EX.941, with more effective spigot for spring. Oil holes on valve end of inlet rockers plugged, but arranged to allow a very slight leak of oil. The exhaust valves do not shew any signs of distortion or burning. The inlet valves are very good. There is a fair amount of carbon on underside of valves. The condition of all valve stems is very good. The guides of exhaust valves have worn slightly elongated. The clearance of inlet valves has remained constant throughout the test. The clearance of the exhaust valves has again decreased to .0015" during the last 2,500 miles. On No. 2 exhaust valve the clearance was all taken up, the valve being just free. From examination, this appears to be due to the seats of the valves becoming worn, rather than due to the stretching of the valves. We have had an occasional tappet noise. This has been caused by the valve spring clicking on the spigot. We presume the cause of this is the knife-like edge on either end of springs cutting into the spigot, & causing a tappet noise, due to a distortion effect of spring when compressed. It is possible to make a noisy valve quiet by turning the spring round half a turn, which we presume corrects the distortion. The rocker arms have functioned O.K. Lubrication of same has been satisfactory, & the bearings are in good condition. We have not experienced any trouble with excess of oil getting down valve guides. The felt crumpets are quite good, & do not shew any signs of being burnt, or becoming hard. | ||