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).
Oil consumption tests comparing different piston types and chassis configurations.
| Identifier | ExFiles\Box 87\2\ scan0132 | |
| Date | 10th February 1936 | |
| -2- The oil consumption when using Aerolite pistons on endurance tests was found to be good, being 1.0 pints/hour compared with 1.5 to 2.0 pints/hour with EB.1299 pistons. The reports of 10,000 miles trials in France throw some interesting light on the subject of oil consumptions. The first Bentley in France was fitted with 20/25 pistons E.57122 and these gave an average consumption of 745 miles/gallon. EB.495 pistons in a later engine gave a consumption of 854 miles/gall. whilst a set of EB.1299 pistons fitted the next time this car (1-B-IV) went to France gave a consumption of 681 miles/gall. One of the most interesting tests was when 4-B-IV fitted with B-3 unit did 4,000 miles test in England. The unit was fitted with EB.1299 pistons for the first 1900 miles and the oil consumption was 680 miles/gall. For the following 2300 miles Aerolite pistons were fitted, and the consumption was 1264 miles/gall. 4-B-IV chassis, fitted later with B-7 unit and Aerolite pistons, completed 14,000 miles in France with an average oil consumption over the test of 1529 miles/gall. The next chassis to undergo tests in France was 5-B-IV fitted with B-10 unit and Aerolite pistons, and the average oil consumption was at the completion of 10,000 miles, 1368 miles/gall. It is also interesting to note that B-56-BN{W.O. Bentley / Mr Barrington} fitted with 3.500" dia. Aerolite pistons had an average oil consumption of only 714 miles/gall., but there is a question of whether the rocker shaft had been fitted the wrong way round, at any rate when the engine had been stripped and rebuilt with a new set of Aerolite pistons the consumption dropped to 1544 miles/gall., and on the last day's run the consumption figures were at the high figure of 1860 miles/gall., which figure is considerably better than anything obtained before on Bentleys. With regard to the question of fitting the rocker shaft the wrong way, various results have been obtained by both the Test Dept. and Repair Dept., in some cases where the shaft has been fitted the wrong way the oil consumption has been halved by fitting the shaft the correct way, but on other chassis it did not make much difference. | ||