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).
Tests regarding pre-ignition trouble on an India-4 turbulent head by comparing cylinder head temperatures.
| Identifier | ExFiles\Box 19\7\ Scan134 | |
| Date | 18th April 1929 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to SG.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} 4790 Hs{Lord Ernest Hives - Chair}/ACL1/LG18.4.29: X218 X1643 X790 INDIA 1V - COMPRESSION RATIO AND PRE-IGNITION. We have made some further tests regarding the pre-ignition trouble experienced on the 5.6/1 compression ratio India-4 turbulent head. By means of thermo couples attached to copper washers placed between the spark plugs and plug seats in the cylinder head we were able to record the temperature at that position and also compare the results with similar tests made on the standard cast iron 20 HP. head. The engine with the cast iron head however had a compression ratio of 5.4 : 1 compared with 5.6 : 1 on the aluminium head. Lodge A.40 sparking plugs - which we use on F.{Mr Friese} aero engines - were used so that our temperatures would not be upset by preignition. The average temperature of the six plug seats recorded with the aluminium head was 192°C while on the cast iron head the corresponding temperature was 186°C. We were rather surprised the difference was so small. It was found that the temperatures at the different cyls. varied considerably, the maximum reading on the aluminium head being 248°C and the minimum 161°C. On the cast iron head the max. temp. recorded was 212°C and the minimum 168°C. All the tests were carried out with the cyl. water temp. at 80°C. The appended diagram shews the position of the thermo couples which should record contd :- | ||