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).
Report from Specialloid Limited detailing piston wear measurements after 53,990.4 miles.
| Identifier | ExFiles\Box 148\4\ scan0292 | |
| Date | 22th September 1934 | |
| Specialloid LIMITED Friern Park North Finchley. N.12. -/- Messrs. Rolls-Royce, Limited, 22nd September, 1934. Pistons fitted 23rd May, 1934. Pistons removed 30th April, 1934. TOTAL MILEAGE: :::::::53,990.4 1) Piston lands....Wear does not exceed .001" over all lands 2) Ring-grooves....First compression ring .005" to .010". Second compression ring .002" to .004". Third and fourth compression rings..............002". Teetor ring-grooves.max.001". 3) Gudgeon pin housings; Maximum wear .0015". 4) Gudgeon pins; Wear at centre .0005" to .001" at extreme ends (assuming original diameter as standard). 5) Rings: Wear on first compression ring...008" to .010". Wear on second....................003" to .005". Wear on third and fourth...........001" to .002". Wear on teetor rings.............0005" to .001" When it is considered that these Pistons have been operating in a Bus engine for nearly 60,000 miles and have been subjected to arduous conditions such as are experienced on London traffic conditions, it will be agreed by all that the performance is exceptionally good. We have a number of instances on record where Specialloid Pistons fitted to Bus engines have completed from 150,000 to 180,000 miles of service, maintaining under even such prolonged life a reasonable oil consumption performance. Under separate cover we have despatched, for the attention of Mr. Robotham, four sample Pistons:- One whole Piston is to our reference H.81, and this is suitable for Hispano-Suiza Engine; this Piston has been subjected to the alumilite treatment and has been sent for your examination as we understand from our Mr. McConnell you are interested in the skin hardness process. We are experimenting with a number of anodised Pistons and on Monday we shall post a further letter outlining the main details of the alumilite process. | ||