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).
The 32-hour test run of the latest pedestal pistons, detailing performance, issues with piston knock, and gudgeon pin fixing.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan107 | |
| Date | 1st August 1926 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair}/ACL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} H.{Arthur M. Hanbury - Head Complaints} c. to BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} ORIGINAL Hs{Lord Ernest Hives - Chair}/ACL1/LG30. 8. 26. Y8040 X4490 PEDESTAL PISTONS We have completed 32 hrs. running with the latest pedestal pistons - LeC.2237 - in a test bench engine. Three hours of this running consisted of 3000 r.p.m. at full load. They were quite satisfactory and shewed no signs of tightness during the run. Duralumin and bronze piston ring stops were tried and both were quite reliable. Examination after the tests shewed that the bedding was quite good and even. With regard to piston knocks with this particular set and with the latest stiffened skirt cylinders, we have had no trouble except for a 'knock' when listening at the cyl. base with a sounding rod. With this particular test engine we were not troubled previously with knocks when using the present std. pistons so have yet to test them on an engine known to be prone to knocks. We think that the method of gudgeon pin fixing should prove to be a considerable advantage in practice over the present method and tend to eliminate distortion both in the initial fixing and again under the fluctuations of temperature when in service on the engine. This is one of the factors we consider gives rise to a lot of the knocking troubles on production cars. Another factor causing trouble is local tightness and the greater flexibility possible with these pistons contd :- | ||