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 challenges of fitting aluminium pistons, focusing on the trade-off between piston knock and seizure.
| Identifier | ExFiles\Box 35\2\ scan 142 | |
| Date | 26th September 1919 | |
| COPY. En. from EP.{G. Eric Platford - Chief Quality Engineer} c. to HS.{Lord Ernest Hives - Chair} EP{G. Eric Platford - Chief Quality Engineer}4/F30.919. I have noted your Bn{W.O. Bentley / Mr Barrington}6/W26.9.19 and have discussed the question of fitting aluminium pistons further with Mr.Hives. The present position is that we cannot with any confidence pass cars through test as fit for delivery in a state where they are free from audible piston knocks when hot, and at the same time will not seize. The position also is that on the cars on test some pistons knock and others do not, but this condition is no guarantee as regards the correct clearance, and in order to guarantee that the piston knock will not develop and that its action will be consistent, we have to refit pistons with the latest clearance. With this clearance there is the danger of seizing up; at the same time, any further clearance gives piston knocks. Our practice is therefore to fit pistons with the latest clearance limit, and to run and ease in the cylinders. Even then, we do not feel at all confident that the cars will not seize, and in easing still further in order to guarantee that this will not take place, piston knocks will invariably develop. This feature was the substance of my conversation with Mr.Hives this morning, with which he concurs. Much as we have struggled with this job, I must be frank and say that with regard to obtaining satisfactory cars which are fit for delivery, having regard to the conditions laid down at our conference with Mr.Royce at Sales Dept., in London, the position is impracticable. EP.{G. Eric Platford - Chief Quality Engineer} | ||