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).
Experiments for pistons with concave crowns and other components to test for oil consumption.
| Identifier | ExFiles\Box 72\1\ scan0025 | |
| Date | 28th April 1925 | |
| To BY.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c.c. to CJ. Hs.{Lord Ernest Hives - Chair} 48880 S E C R E T. E2/M28.4.25. E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. X. 8040 X. 8980 PISTON WITH CONCAVE CROWN AND LOWER SCRAPER RING. We send you herewith LeC. 2055 shewing the above. The following pistons should be prepared from the pattern made for this design and tested for oil consumption. (1) Piston as shewn on this drawing with upper and lower scraper rings, spring skirt, and all rings except the top one pinned. (2) Piston with bottom scraper ring, but skirt left whole, no slots or holes through of any description, and no oil collecting groove or drain holes to upper ring. This piston is required for information as to what extent communications to the cyl. wall destroy the effect of the lower scraper ring. (3) Piston with split skirt, upper rings etc. as (1) but no lower scraper ring, and bottom of skirt machined as per fig. A.{Mr Adams} on the drawing. It is thought that the spring skirt of the standard pistons E.73376 - may act like an 'L' shaped ring scraping oil upwards due to the top being much stiffer than the bottom. Piston (3) is a test to determine this feature. The other experiments that are to be carried out in connection with over-oiling at high speeds are :- (a) The use of mudguards splashers. We are drawing some of these to Mr. Royce's ideas, whereby the splasher is in one piece and extends from the offside crankcase wall only partially across the crankcase. (b) An apron splasher let down in front of each cyl. barrel. (c) The cutting away of the bottom ends of the cyl. barrels so that they drain oil away from the connecting rod big end on each side. E.{Mr Elliott - Chief Engineer} | ||