Study on crankshaft length as the controlling factor for a straight 8-cylinder 3.5' bore engine.
| Identifier | ExFiles\Box 111\2\ scan0322 | |
| Date | 24th March 1938 | |
| Rm. {William Robotham - Chief Engineer} 1044 DA {Bernard Day - Chassis Design} /Jnr. {Charles L. Jenner} 10/G.24.3.38. ---- 800 STRAIGHT 8 ENGINE 3.5" BORE. ------------------------- Having made a study of the length of this type of engine, it is clear to me that the crankshaft dimension is the controlling factor. A five bearing shaft is longer than nine bearings due to the extra cylinder spacing between 2 and 3, 4 and 5, and 6 and 7 cylinders which is used to provide adequate bearing surface and robust crank slabs at these points. A good example of this is the old Essex Terraplane which had 3.2 centres for 1 and 2, but 4.1 between 2 and 3 cylinders. A nine bearing is the best for cylinder block length, however with this we should have to accept narrow intermediates which we have always disliked. Length of Block. -------------- (A). 5 Bearing with water as Buick = 35.125 (B). 9 Bearing with water as Studebaker = 34.05 (C). 5 Bearing without water as Chrysler = (not practical) (D). 9 Bearing without water = 33.4 Phantom 111. = 29.75 25/30 HP. = 26.5 Any internal pictures or drawings of the NASH and CHRYSLER would be useful further information. DA {Bernard Day - Chassis Design} /JNR. {Charles L. Jenner} [Signature] | ||
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).