Mileage tests and experimental fixes for engine knocks using different gudgeon pin designs.
| Identifier | ExFiles\Box 48\1\ Scan122 | |
| Date | 7th September 1920 | |
| Contd. -2- The Drivers' Instruction Car has now completed 7000 miles since these springs were fitted and 19,000 miles since the pistons were fitted. The engine is still satisfactory as regards being free from knocks. As regards the other cars which we have fitted with this arrangement, we have not received any further complaints so assume that it has overcome the trouble. Our experimental tests show, however, that in some cases, although the knock is cured at the dead-light running speeds which are the speeds at which the customers notice it. because the engine is then running very quietly, it comes again when the engine is run faster. For this reason we have fitted to some of our experimental cars gudgeon pins in which the locking screw is made so that instead of contracting the gudgeon pin when they are screwed in, they expand the pin. So far we have found this to work satisfactorily but we have not tested it for a sufficient length of time to say whether it is likely to be permanent. We have also tried gudgeon pins in which each end we have inserted taper wedges. The trouble with this is the difficulty of removing the pin. The point we wish to emphasize is the fact that if we get customers complaining of these knocks we have got to make them happy and the only way we know of at present is to fit springs in the locking screw or gudgeon pins which can be expanded. We have not found nor can we anticipate that either of these things can possibly cause any harm - the question is whether they are Contd. | ||
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).