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).
'F' cylinder tests investigating oil consumption with scraper rings positioned at the top of the piston skirt.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan073 | |
| Date | 1st January 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/ACL. c. to SS.{S. Smith} WOP. c. to Rg.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL Hs{Lord Ernest Hives - Chair}/ACL.1/MJ.1.1.31. X3866. "F" CYLINDER TESTS - OIL CONSUMPTION WITH SCRAPER RINGS AT TOP OF SKIRT. A previous test was made with the perfect circle type scraper having .080 oil groove placed above the gudgeon pin but used in conjunction with liners having increased clearance between blocks, raised rubbers and reduced foot. The oil consumption was good, being 3 pints/hour at 2250 R.P.M. and 7 1/4 pts/hour at 2700 R.P.M. We have now repeated the test but used standard liners instead of the modified ones in order to see if the modifications assisted in improving oil consumption. New piston rings were used in combination with the new standard liners. The oil consumption was approximately the same. Two hours test at 2250 R.P.M. and 441 H.P. gave a consumption of 3 1/4 pts/hour. One hour full throttle at 2700 R.P.M. and 546 H.P. gave a consumption of 8 pts/hour. The outlet oil temperature for the last hour was maintained at 87°C. This test tends to indicate that the modified liners (mods. to reduce distortion) have no appreciable difference in effect on oil consumption. We know however the variations we experience in oil consumption on production engines therefore we should be guarded in assuming that the figure recorded on this test would be representative of other engines built to this scheme. The scraper ring above the gudgeon pin offers the advantage of better piston lubrication being safer for quick starts from cold, and gives ease of assembly of the cylinder block. We should like to make further oil consumption tests with the raised scraper ring to see if we can rely upon obtaining a reasonable oil consumption with this scheme. | ||