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).
Engine design and performance, focusing on Leyland's experiences with C.I. engines, injector pumps, and crankshafts.
| Identifier | ExFiles\Box 140\3\ scan0239 | |
| Date | 17th February 1939 | |
| - 2 - from petrol to C.I. in regard to the gasket and the holding down studs for the head. In their opinion the petrol job is 2/3rds of the load of the Diesel, Leyland hold down their cylinders with seven ½" studs. In regard to the drive for the injector pump, they are quite unfamiliar with any torque fluctuations, all their troubles were hydraulic ones, spilling and excess pressures, they state that any well designed drive and good couplings is satisfactory. Leylands dare not raise their engine speed high enough to reach the six order harmonic of the shaft. They have never needed a spring drive, and have never measured the torsional oscillations of the front end of the crankshaft, they try to give a mileage of 100,000 for the life of the chain. This at times has necessitated making the chain bigger. In the direct injection engine the rate and the direction of the swirl is critical, the inlet valve is accurately timed via its guide and the masking at one side of the valve has to be of the right proportion. Considerable research is necessary to obtain these proportions, in fact the success of the head is dependent on swirl. Leylands troubles are pistons, which gum on the top rings and the torsional of the crankshaft, which limits them to any higher B.M.E.P. An engine must not be run on the fringe of blue smoke in the exhaust, which is a stage before black exhaust. The reason Leylands used the turbulent chamber on the small engine and not on the larger ones was due to having done this work, and they were able to jump in and get the market. The engine has been a considerable amount of worry to them, and they really dislike it. We got the feeling that possibly some of their development is handicapped, because they always keep in mind fuel consumption. [Handwritten diagram titled 'Leyland D.I. Timing' with a circle and radial lines marked with numbers 8, 18, 44, 44] Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} | ||