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 leaks from the clutch valve on American cars, detailing the function and adjustment of the worsted insert.
| Identifier | ExFiles\Box 74\2\ scan0275 | |
| Date | 8th September 1920 | |
| To Cj. from Hs.{Lord Ernest Hives - Chair} X3439 Hs{Lord Ernest Hives - Chair}4/LG8.9.20. X.3614. RE OIL LEAKS FROM CLUTCH VALVE. X.3439. AMERICAN CARS. With reference to the attached correspondence, there appears to be a difference in opinion in America as to how the oiling on the clutch spigot works. The man in America who knows all about this job is Mr. Bagnall as he did a lot of work on it when it was originally fitted to our engines. The worsted which is inserted in the end of the crankshaft is fitted there primarily with the idea of restricting the flow of oil. The fact that it acts as a filter is only a secondary consideration. With the valve away altogether and 20 lbs. pressure in the crankshaft, the amount of oil which should leak through the worsted should be only 5 to 15 drops per minute. If it is more than that, the worsted should be packed tighter. The valve should be adjusted so that there is 1/8" clearance between the valve and the operating plunger. This means that it is only when the clutch if fully depressed that the valve is operated. Although the worsted may only allow 5 to 15 drops per minute to leak through, if the valve is not closing properly, this will cause over-oiling very quickly. There was a number of post-war cars which suffered from excess oil getting into the clutch. All of these which we investigated at Derby were found to be due to either - 1. Bad workmanship on the valve seating. 2. Faulty adjustment. Contd. R.R. 235A 100(T) (S.G. 643. 19-2-20) G.2618 | ||