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).
Testing and performance of split cast iron pistons.
Identifier | ExFiles\Box 77\3\ scan0210 | |
Date | 24th January 1920 | |
X.3752 To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Rn.{Mr Robinson} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to EP.{G. Eric Platford - Chief Quality Engineer} Hsl/LG 24.1.20. X.3754. - RE SPLIT CAST IRON PISTONS. X.682. We are running 7-CA fitted with a set of the cast iron pistons we used previous to the war except that they are split on the non-pressure side. The point one does not like about these pistons is that when they are split they feel very flexible.- it does not follow of course that they are flexible when in the cylinder. We have made a test by squeezing a piston in between two blocks which formed a true size cylinder, we found on there that it was the amount of grinding off the side which controlled the flexibility of the piston. The pistons were ground the same size as the cylinder bore. We have run the car on the dynamometer and on the road; the car was quite free at all speeds on the dynamometer and there are no signs of piston knocks. The most marked difference we find in changing over the car from aluminium to cast iron pistons is the increase in detonations. We think this is quite a big point because if customers can run twice as long without cleaning out the carbon, the car should give greater satisfaction. The cost of cleaning out the carbon must be double to what it was before the war. Benzol does not appear to very extensively used by our customers. We think, however, that we should persevere with the flexible cast iron piston because at present we are making Contd. | ||