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).
Inconsistent oil consumption results due to the lapping of 'L' shaped piston rings.
| Identifier | ExFiles\Box 72\1\ scan0028 | |
| Date | 13th May 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. +8980 Expl. No. REF. HS{Lord Ernest Hives - Chair}4/LG13.5.25. to R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} BY.{R.W. Bailey - Chief Engineer} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to Wor.{Arthur Wormald - General Works Manager} EAC. OIL CONSUMPTION. +8040 We find that the inconsistent results we have obtained with the 'L' shaped piston rings have been due to the amount of lapping they have received. It is our standard practice to lap all rings in with a cutting compound in a dummy cylinder on a special piston. We have obtained a consumption of 1900 m.p.g. on a 'V' series car after fitting 'L' shaped rings which had not been lapped - after lapping, the consumption will drop to 500 to 800 m.p.g. Watching the amount of oil which is splashed through the guards, has not shewn us very much. The amount of oil which is splashed from the crankshaft is nothing like one would expect from the oil consumption. It appears to be very little more than we have observed on a 40/50 engine. We shall be running the pistons fitted with the lower scraper ring tomorrow. Hs.{Lord Ernest Hives - Chair} | ||