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).
Fuel detonation characteristics and the performance of various engine gaskets.
Identifier | ExFiles\Box 90a\6\ Scan127 | |
Date | 1st October 1936 | |
-6- (4) "Esso" Ethyl. Tested at 9 : 1 Comp. Ratio. General characteristics of detonation only slightly worse than at 8.5: 1 Comp. Ratio, detonation fading out at 3150 R.P.M. Full Throttle. The variation between max. and min. combustion chamber temperatures slightly more noticeable. (5) Cleveland Discol. Tested at 8.5 : 1 Comp. Ratio. The results with this fuel were the same in comparison as those given in test (3) on Ethyl at 9 : 1 Comp. Ratio; in other words, Ethyl is worth half a ratio, compared with Discol under these particular running conditions. (6) National Benzol Mixture. Tested at 8.5:1 Comp. Ratio. Detonations throughout the speed range. The difference between max. andmin. combustion chamber temperatures is now very marked, by the snap acceleration method. Very poor for power holding at all speeds, full throttle. Gaskets. Four types of gasket were tried. The copper and asbestos type, as standard on the 4 1/4 litre Bentley, was found to be quite unsuitable for use with a high compression ratio. The surface area of copper exposed, being sufficient to cause serious pre-ignition. After only a few hours' running with occasional bursts at full throttle, the copper in places was burned through to the asbestos. A solid copper gasket was tried, having the same area of copper exposed, and caused the same degree of pre-ignition. Also it was found impossible to make a water-tight joint between the head and the block. The third type tested was an asbestos material pressed into wire mesh, known as "Klingerit 1000". This was found to be the most useless type tested. As soon as the engine was started up, the jointing was blown through to the water passages. The only gasket to stand up proved to be the "Corrujoint", a three-ply nickel alloy gasket having a total thickness of .030". Water-tight joints are made by corrugations locally placed round the portions to be sealed. The gasket can only be used once, for obvious reasons. This type was used in the 1934/5/6 T.T. races on the Bentley engine. | ||