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).
Ongoing issue of 'elusive knocks' in service cars and proposing a solution involving redesigned gudgeon pins.
| Identifier | ExFiles\Box 48\1\ Scan128 | |
| Date | 7th January 1921 | |
| BHW (for Exp. Dept.) c. to Sy. c. to E.H. c. to EPC. X 4190 A.T. EP{G. Eric Platford - Chief Quality Engineer}2/F7.1.21. X 4190 RE. ELUSIVE KNOCKS. We still continue to receive complaints of the above developing on cars in service, and this matter has been receiving the attention of the Experimental Dept. for some time. Hs.{Lord Ernest Hives - Chair} reported on the matter in his memo. to R.{Sir Henry Royce}, ref. Hs{Lord Ernest Hives - Chair}4/LG27.9.20. He has since made further tests by fixing gudgeon pins in which the locking screw is fixed with the taper fitting portion at the top of the gudgeon pin and the threaded portion at the bottom, which is the opposite way to which these locking screws are fitted at present. With this scheme it is maintained that a tighter fitting gudgeon pin in the piston is obtained, and several sets of such gudgeon pins have been fixed on cars which have been giving trouble with elusive knocks. A definite cure has been effected by this means, although we have not run any of these for any considerable time; at the same time there certainly have been no disadvantages in fitting these special pins. We are anxious that some definite action should be taken so that we can turn out cars which will not suffer from this defect, and we have now received a cable from Hs{Lord Ernest Hives - Chair} pointing out that America are having the same experience with elusive knocks. Hs{Lord Ernest Hives - Chair} recommends that we should adopt as an immediate cure, gudgeon pins with expanding lock screws as above, and also points out that these have run successfully for 4,000 miles on 4-EX, apart from having been run on other Trials cars. We shall be glad if you will take the necessary action immediately, as we consider it of the utmost importance that some action should be taken in order that we can deal with this trouble, not only as regards curing the existing cars but by preventing cars going out in which this trouble will develop. EP.{G. Eric Platford - Chief Quality Engineer} | ||