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).
Issues with cylinder expansion, dirt ingress, oil leaks, and the performance of the clutch, dynamo, and gearbox.
| Identifier | Morton\M3.5\ img015 | |
| Date | 11th April 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. The expansion of the cylinders and exhaust pipes may be in an upward motion, which is the cause of the flange becoming cracked. Cast iron choke valve in down-take pipe - this has stuck open recently during a high speed run. Dismantling shews spindle distorted, but this valve still rattles when engine is running normally. Exhaust pipes do not shew any tendency to scale. Fan and drive O.K. Engine louvres - after very dirty wet run, slight amount of dirt had got up on to dashboard on exhaust side. Relief valve unit (oil) - this should have better protection from dirt. If oil pressure drops, and it is necessary to take this oil unit down, it is almost impossible to prevent dirt getting into the valves or on the crankcase face, which means when re-fitted oil leaks. Also, it is in a very inaccessible position. We have been running without oil filler cap but at present cannot say that there is any improvement in oil consumption. Oil pipe from relief valve unit to timing gears - a hole has been chafed in this pipe by the front undershield at the corner where the pocket is rivetted on (O.S.) The undershield is also rubbing on front engine case. Dynamo - from some cause, not yet ascertained, does not charge for the first twenty miles approx. early morning run, after which it functions O.K. We have examined commutator and cutout - both seem to be O.K. Clutch - considerably improved. Jiggers have almost disappeared, it is only on reverse that these occur. We should say now that the clutch is equal to 40/50 HP. Stopping of clutch is O.K. when cold, but is sluggish when hot. Front axle - outside examination, pivots and bearings O.K. Brake operating shafts with larger bearings - no wear is noticeable. Front spring clips - tightened up 3/4 of a turn. Off-side bottom two leaves worked out of line 1/4". These have been straightened. All leaves well lubricated, and all are O.K. UNDERSHIELD. Modified undershield to scheme 618/9/20. The cause of dirt getting in this shield is faulty fitting round the engine base and sides. It is imperative that it should be a good fit. Unfortunately, there is a big hole in this undershield for the starter motor, which in standard practice, will not be there on 'Y' series production cars, where a great deal of dirt gets on to present starter motor and chain. GEARBOX. Side shaft poor cold. Oil leaks out of tower where change speed spindle enters. Slight oil leak rear bearing. Starter motor chain taken up on notch on adjustment. Servo and mechanism O.K. EXHAUST PIPES & SILENCERS. Exhaust lagging on rear and front silencers knocked up Contd :- | ||