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).
Reported disintegration of aluminium pistons with a die-cast aluminium founder.
| Identifier | ExFiles\Box 35\2\ scan 187 | |
| Date | 8th January 1920 | |
| X.2748 To R.{Sir Henry Royce} from Bn.{W.O. Bentley / Mr Barrington} Copy to CJ. " " Wd.{Mr Wood/Mr Whitehead} " " Da.{Bernard Day - Chassis Design} " " Hs.{Lord Ernest Hives - Chair} " " Ck.{Mr Clark} Copy to By.{R.W. Bailey - Chief Engineer} Bn{W.O. Bentley / Mr Barrington}5/W8.1.20. X.2609b. Referring to Disintegration of Aluminium Pistons. X.2748. Mr. Whitehead kindly arranged for Mr. Fowler of Messrs. Fermans, (Die cast Aluminium Founders) to put before us on Wednesday, the 7th inst., all the information he had with regard to the reported disintegration of aluminium pistons experienced by some of our competitors. Mr. Fowler was not able to bring today the sample of what he terms a disintegration piston, and a similar sample of a perfect piston which he had hoped to do, but he promises that these shall follow. He describes a disintegrated piston as one in which the cylindrical surface chiefly at and near the piston ring bands has come away in fine particles and become lodged or trapped in the ring grooves, and the rings have become quite firmly embedded in their grooves. I gathered that there is definite evidence of this powered aluminium in addition to any bruising or rubbing of the aluminium at the edges of the lands to embed the rings. From Mr. Fowler's description we have a very strong impression that he is really quoting cases of pistons which have seized. We are aware that if the surface of a piston is raised in temperature either by seizing or faulty lubrication, or such over-heating as one occasionally gets in an air cooled engine generally the aluminium does not run but the structure of the metal is destroyed and breaks up almost like the powdering of a biscuit. We think therefore that the disintegration described by Mr. Fowler is not new to us but is the characteristic we obtained when a piston seized. We have suspected that the disintegration talked of might have been the trouble experienced during the war with certain pistons which were difficult as regards die castings, and which suffer from cracking and which are at present known to be giving a lot of trouble through a recurrence of this difficulty. Mr. Fowler was fully aware of the trouble referred to and his explanation renders it clear that the reported disintegration has nothing to do with this cracking trouble. It was clear from this conversation that both Rovers and Crossleys have abandoned aluminium pistons owing to the difficulty they have experienced in obtaining a piston which is sufficiently tight to avoid knocking and not too tight to seize when run hard. Mr. Fowler suggested that some of the trouble may have been due to the use of faulty lubricant with pistons which were only just satisfactory with good lubricant. Contd | ||