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 solid tappets on an experimental Phantom III chassis.
| Identifier | ExFiles\Box 91\2\ scan0325 | |
| Date | 6th September 1937 | |
| COPY. ---- N/W. Mx.{John H Maddocks - Chief Proving Officer} from Br.{T. E. Bellringer - Repair Manager} Br.2/LS.6.9.37. re Phantom III Chassis No. 32-EX. (Experimental) I used the above car during this week-end as arranged with you, and first and foremost I am completely converted to the idea of dropping hydraulic tappets and introducing solid tappets such as are fitted to the above car. No doubt you will understand that I was very prejudiced in the beginning owing to the two or three years' nightmare we have experienced at N with noisy valve mechanism on Phantom II's fitted with high-lift cam shafts and heavy valves. The engine appears to be equally as quiet as the standard ones fitted with hydraulic tappets, in spite of the fact that it has run in its present condition 15,000 miles. Therefore, I think the following features make it highly desirable for this type of tappets to be introduced at once in production. 1. Cheaper manufacture. 2. Very satisfactory oil consumption without having to resort to very tight valve guides which would probably have to be changed each decarbonisation. 3. The fact that the tappets can be set with .012" clearance and the probability that they will not have to be touched by chauffeurs between decarbonisations. 4. We are doing away with the risk of hydraulic tappets going wrong in customers' hands when miles away from service. The above is always assuming that the camshaft and tappet mechanism can be produced in production to give the same results as you have obtained on 32-EX. | ||