Issues with non-standard tyres, inconsistent tappet oiling, and high oil temperatures.
| Identifier | ExFiles\Box 11\5\ 05-page025 | |
| Date | 9th April 1934 | |
| To HS {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} From G.W.H. Hotel de France, Chateauroux(French test region), FRANCE. 9.4.34 28-EX. We have received your memo of the 7th. TYRES. As we have been cut off altogether from the Paris Depot, I have not attempted to correspond with them. The tyres we are using are not standard, they are the new type '90', silent tread which Dunlops wish us to standardise. However, as there is no time now to receive tyres from England, I shall order two French Dunlops which on all our tests, have given a 1,000 miles shorter life, from the Paris Depot, and ask them to charge Derby for same. TAPPETS. The trouble with the tappets is the inconsistency of the mechanism to supply oil to the plungers. One has to set each tappet to give the quantity of oil. The limits allowed in each part brings this about. The trouble with the set fitted to this car is, different clearances have been made to get the tappets to work at all consistently, No.6 and No.12 the clearance is evidently too great and will not hold the oil after supply has ceased. It is not a question of eccentrics sticking, these move up and down freely. We can quieten them immediately by poking the valve with a piece of wire to let out the air and get oil in, but we are not doing this. We are seeing how far we have to travel before they right themselves. Proving that the leak is too great one has only to stop to fill up with petrol and they are noisy again. If a finer filter is needed, the experts who dealt with the job should have incorporated it in the scheme. If all these precautions have to be taken, then we are in for some trouble with production. At present they are anything but a production job. RE. OIL TEMPERATURES. We cannot give you any definite reason why the oil temperatures are high other than the engine is revving higher, 7 x 19, tyres; 11 x 41 axle ratio. We have not had such high temperatures before with a Phantom. We have got two pistons blowing badly into the crankcase. We are therefore dismantling the engine to find the cause, also at the same time a reason for the heavy oil consumption. G.W.H. oncock. | ||
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).