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).
Diagnosing engine knocking and popping in car 7-CA, caused by a rotted petrol filter and pre-ignition.
| Identifier | Morton\M3.7\ img012 | |
| Date | 12th August 1919 | |
| To R.{Sir Henry Royce} from EH. C. to Cl. C. to EW. C. to F.{Mr Friese} C. to Dd. ORIGINAL EH1/LG12.8.19. 12th. Aug. 1919. 2 RE 7-CA CAR. X.682 We are sending to you the Petrol Filter out of Car 7-CA. You will notice that this is partly rotted away. We think that there is no doubt that this has been part of the cause of the trouble with the running on this car. When we took the car from you, we noticed, as you pointed out, that as soon as we reached somewhere about 50 M.P.H. the car started knocking and would not increase in speed. Occasionally also it popped in the carburetter. We have found that practically all of this trouble disappears if we fit a new set of sparking plugs. The popping was caused by pre-ignition. The knocking in the engine has disappeared except under the most extreme conditions when it comes on slightly. We have carried out several comparative tests with the sparking plugs as we took over the car and with a new set of K.L.G. plugs to confirm the results. We noticed with the bad plugs that when the popping occurred, the mixture did appear to go weak. We think that very possibly the flame in the induction pipe did dry up the petrol and also might have heated it so that it boiled. The car, now that we have fitted new petrol filter and new plugs, runs perfectly well under normal conditions with the petrol taps arranged so that the car is running on the main tank. Contd. R R 532v (200.L) (B'D' 408 89-I-19) | ||