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).
Experiments with post-war piston rings to resolve ring clap issues on pre-war pistons.
| Identifier | ExFiles\Box 16\1\ Scan151 | |
| Date | 24th September 1923 | |
| To BY.{R.W. Bailey - Chief Engineer} From Hm.{Capt. W. Hallam - Head Repairs} " Hs.{Lord Ernest Hives - Chair} 1741 Hm{Capt. W. Hallam - Head Repairs}11/W24.9.23. Re Post-war Piston Rings on pre-war Pistons. Further to Hm{Capt. W. Hallam - Head Repairs}/NRC{N. R. Chandler}1/D4.9.23. Hm{Capt. W. Hallam - Head Repairs}4/W5.9.23. In order to overcome piston ring claps of which we get a fair number of complaints, we have now carried out two sets of experiments. 1. An engine has been run on engine test stand with reduced clearances at the bars for 2,000 miles. These pistons were fitted with the present standard ring. Result was satisfactory and shows that we have not exceeded the reduced clearance. Carbon formed under the top ring very early but we were not able to produce ring clap. It should be noted that ring clap starts at between 1,000 and 1,500 miles running. 2. We ran an engine on engine test stand 3,800 miles and 700 miles on the road with reduced clearances at the bars, and 4 post-war rings. After 2,000 miles on engine test stand the cylinders and pistons were dismantled, and without removing the carbon formed the car was run on the road for 500 miles, and no ring claps were heard. It was returned to the test stand and without removing the carbon run a further 1,800 miles. It was then run on the road a further 200 miles and no sign of ring clap was heard. The carbon formed was not interfered with at any of the changes. These pistons and rings are very good for gas tightness. The same amount of carbon does not form under the rings as in the case of the wide rings. We should be glad of permission to use these rings on all pre-war pistons, and to get off at once sets to all the people who are complaining. Hm.{Capt. W. Hallam - Head Repairs} | ||