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).
Investigation into the cause of distinct piston knocks in hot engines, including experiments on rod and piston alignment.
| Identifier | WestWitteringFiles\C\September1919\ Scan18 | |
| Date | 20th September 1919 | |
| To R.{Sir Henry Royce} from EH. c. to SJ. c. to BN.{W.O. Bentley / Mr Barrington} c. to R.{Sir Henry Royce} c. to Da.{Bernard Day - Chassis Design} c. to EP.{G. Eric Platford - Chief Quality Engineer} AN HS{Lord Ernest Hives - Chair} SUPER-CLASSIC (4) ORIGINAL. RH{R. Hollingworth}/LG20.9.19. 20th. Sept. 1919. 2 Extracts X.3400 X.2448 X.3651 EXPERIMENTS IN CONNECTION WITH PISTON KNOCKS. There are a number of cars on test which have distinct piston knocks even when the engine is hot. It has been decided at the Works that these knocks are too bad to allow the car to be delivered. We have examined a car with these knocks to see if we can find any reason for it. So far we cannot explain it. The rods that knock are certainly more true than some of those which do not but we do get cases where we have a fairly true rod and yet no distinct knock. We know no reason why, if the cast iron piston which runs with absolute minimum amount of clearance, knocks when the hot that there should be any difference with the aluminium ones when they reach their working temperature. We have tried an engine with absolute true rods, pistons and cylinders to see whether it was possible we could make them all knock. We found, however, that only three of them would knock, and then the degree varied at different times under the same conditions. As 1.EX is often being quoted as a model, we have removed the cylinders and checked up the alignment of rods and pistons. Below are the results:- Contd:over. | ||