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).
Fitting of pistons, comparing different methods and standardizing the practice.
| Identifier | ExFiles\Box 148\3\ scan0020 | |
| Date | 1st June 1923 | |
| Sft{Mr Swift} c. to BY c. to Hs.{Lord Ernest Hives - Chair} X2748 EP{G. Eric Platford - Chief Quality Engineer}7/H1.6.23. re. Fitting of Pistons. X2748 During my inspection visits to Springfield trouble was experienced with piston bedding, which could only definitely be overcome by hand fitting. I was also anxious to try and obtain some information as to whether their long skirt piston had any advantage to recommend itself in preference to our present standard, which did not appear to have been proved at that time. Springfield were anxious to produce pistons which did not require any hand fitting at all, but I pointed out that we had tried this and it had not been successful, and at least it would be necessary for the pistons to be dismantled after the first dynamometer test and some hand fitting to be done, owing to the heating and distortion effect which the pistons would have after having gone through this test. We should, however, be very glad to know what their final results were in this direction. I have now been able to obtain from them the practice which has now been standardised, and which practically confirms what we are now doing, which is to the effect that the eccentric grinding is now being carried out so that a minimum of hand filing only is required after the first engine running in and power test. I attach to BY's copy of this memo their latest print of A2248, which gives details of the construction and method of production. Oy. also reports on this matter as follows:- " In reply to your enquiry EP{G. Eric Platford - Chief Quality Engineer}2/H20.4.23, I send herewith print of the piston A2248 which shows what we have been able to do so far in the way of cutting out filing. You will notice that whereas before we offset the piston .020" for eccentric grinding, we now offset it only .016". By grinding side clearance to 4.484-2 at top and 4.491-2 at bottom (say 15 and 9 thou) we get left a bedding area approximately 1.300 wide at the top and 2.750 wide at the bottom. CONTINUED | ||