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 valve mechanism issues, proposed solutions, and future work on cylinder head design and performance testing.
| Identifier | ExFiles\Box 133\2\ scan0064 | |
| Date | 26th July 1934 | |
| -6- Hs{Lord Ernest Hives - Chair}/CHP.15/KM.26.7.34. Valve Timing Phase adjustment mechanism. After running 36 hrs. 25 mins. this mechanism (exhaust valve) had become very noisy owing to an excessive amount of backlash having developed in the splines. It was decided, therefore, to fit a new set of hardened parts (EB.1349/57/8/9) to both valves. The trouble was apparently initially caused by the use of incorrect springs in the dampers of the drives, thus allowing a reversal of torque in the splined members as the cam passed over its highest lift position. Valve Tappets and Push Rods. When running the unit with short exhaust valve lift duration, we have twice experienced a fractured tappet and bent push-rod. This failure has also caused damage to the cup of the tappet adjusting piece. On the same occasions the inlet tappet has been found to be severely bent, resulting in one instance in a cracked tappet guide. An improved design of tappet is shortly to be fitted to overcome this trouble. FUTURE WORK. Ramp Head. Experiments with smaller inlet valves with a view to reducing detonation without loss of power. A modified head is almost ready for test which incorporates more turbulence at end of compression, and different plug positions. While it is realised that the side position of the plug is impossible to attain in the multi-cyl. unit, it will definitely prove whether the present position is the cause of the excessive detonation with this type of head. Air Consumption. Tackle is now rigged up for the measurement of air consumption, which will be used for the comparison of different sized valve and valve timings. Motoring Losses. Tackle for this work will be available in the course of a few days, when an estimation of the motoring losses will be made. Hs{Lord Ernest Hives - Chair}/C.H.Parkinson. | ||