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).
Observations during a 32-hour endurance run, focusing on valve failures, valve spring issues, and oil leaks.
| Identifier | WestWitteringFiles\K\October1923\ Scan62 | |
| Date | 19th October 1923 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT Expl. No. 9771 REF: HES/LGT.19.10.23. OBSERVATIONS DURING 32 HRS. ENDURANCE RUN. VALVES. Exhaust valves (45° tulip - Quickstep steel) were badly burned on two occasions. This was due to the initial tappet clearance of .005" being insufficient to allow the valves to seat correctly at speed of its maximum output. The failures were similar to those of this type of valve in the standard 40/50 R-R.{Sir Henry Royce} After the second failure the initial tappet clearance was set to .007" and after 22 hrs. the valves were in fair condition. VALVE SPRINGS. Two failures of exhaust valve springs. 2500 r.p.m. is just the limiting speed at which valves do not bounce - at a speed of 2520, bouncing shows its presence on the running of the engine by a sudden drop in the M.E.P. OIL LEAKS. The chief loss of oil is from behind the flywheel. The escape from this point is excessive at speeds above 2000 r.p.m. A slight improvement is made by removing the oil filler cap and probably the addition of some form of crankcase breather may prove beneficial. The pressure in the crankcase is .250" of water at 2000 r.p.m., rising to .275" of water at 2500 r.p.m. Slight suction effect is caused by the rotation of the flywheel and seems largely due to the starter contd.. | ||