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).
Oil consumption tests for different piston and ring configurations.
| Identifier | ExFiles\Box 132\4\ scan0096 | |
| Date | 19th October 1937 | |
| -4- latter case blow-by was excessive, due presumably to leakage past the stops. All curves were taken on the test bed under full throttle conditions. The piston using stops does not settle down to any steady figure as curve (6) shows, this result is typical of stopped pistons. Past experience has also shown that stopped rings have a greater tendency towards 'gumming-up' besides the piston being more expensive to produce, added to which is always the danger of stops becoming loose and causing serious damage to piston and cylinder. On Fig. I it is also interesting to note the difference made to oil consumption by changing scraper rings and compression rings. Curve (2) is similar to curve (1) except that the scraper rings have been changed, the increase in consumption is not very great. Curve (3) shows the effect of fitting new compression rings, the consumption rising immediately from 0.9 pts/hr. to over 4pts/hr. Fig. II is interesting since it shows that blanking up the holes in the scraper ring groove does not upset oil consumption as shown by curve (1). Curve (4) shows the effect of filling a radius on the lower edges of all rings, again consumption is not upset. The result FIG. I 25/30 OIL CONSUMPTION TESTS. R.R. SPLIT SKIRT PISTONS. MOTORINE 'G' OIL. PRESS 24 LB/SQ" OIL VISCOSITY:- 70 SECS. REDWOOD No1. SCALE AT 100°C. 28,000 " " " " " " 0°C OIL CONSUMPTION (PTS/HR) HRS RUN CURVE ① STD. COMP. RINGS. RM{William Robotham - Chief Engineer} 81 SCRAPER RINGS. GROUND FINISH. ② As ① BUT STD. SCRAPER RINGS. GROUND FINISH. ③ NEW STD. COMP. RINGS FITTED. ④ COMP. RINGS AS ③ BUT NEW RM.{William Robotham - Chief Engineer} 81. SCRAPER RINGS, TURNED FINISH. ⑤ PISTONS, RINGS & CYLINDER BLOCK OFF PRODUCTION ENGINE. ⑥ STD. PISTONS & RINGS USING STOPS. MTHS{Reg Matthews} 7.1.37 | ||