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).
Excessive oil consumption and smokey exhaust in Goshawk engines, with a proposed solution of beveling piston rings.
| Identifier | ExFiles\Box 48\4\ Scan175 | |
| Date | 9th October 1922 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} X4238 Hs{Lord Ernest Hives - Chair}3/LG9.10.22. GOSHAWK 11. X.4134. X.4224. X.4238 There have been one or two cases of excessive oil consumption on Goshawk engines. The consumption in some cases has been as low as 400/500 m.p.g. These same engines have suffered from smokey exhaust after running light. Sales have complained of the smokey exhaust on 4-G-11. This car is getting worse in this respect although the engine has not been touched. We have proved the oil is working passed the pistons and not getting down the valve guides. We have, on two engines, been able to overcome this excessive oil consumption and smokey exhaust by beveling the lower edge of the scraper ring as follows:- BEVEL We have used this method of piston rings in a number of obstinate oiling cases on the 40/50 with success. When we first tried the bevel ring, we had the bevel on the top edge. We found this appeared to make no difference but by reversing the ring we were able to considerably cut down the amount of oil which leaked passed. We are confirming this test. The production Goshawks are liable to smoke after the engine has been run light for a while. We recommend contd:- | ||