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 component wear and material selection, referencing Cadillac and Ford.
| Identifier | ExFiles\Box 158\5\ scan0068 | |
| Date | 25th April 1940 | |
| Rm{William Robotham - Chief Engineer} - 4. Serial No.102. OY.3/D/Apr.25.40. Their latest Feroxed Perfect Circle ring makes bore wear measurements an "exact science". These rings are flat honed on the faces to permit free motion in the grooves under pressure. What is worrying Cadillac now is how to get "bad" iron in the bores at the upper end, where the pressure in the mold normally gives them a close grain structure. On L-head engines the upper end of the bore in the immediate vicinity of the exhaust valve becomes expanded inwards towards the piston by the heating effect of the flame travelling out through the valve, as can be seen through the quartz window. They would like to get rid of the resulting hard bearing, don't know how, and would welcome suggestions. It is climbing this lump on the bore which makes the rings tired. A similar effect occurs in the Ford liners, but here the entire valve side of the upper end of the liner expands till it is compressed beyond the elastic limit, then straightens out when it cools and tries to lock the pistons. Carbon fills in back of the liner and adds to the trouble. Valve Guides. Cadillac are trying these in sintered cast iron, which proves to be ideal metal for the job. (Now used for oil pump gears). Cadillac are only doubtful of mechanical strength of this metal for insertion, but, if this is poor, the guides can be carburized and hardened or heat-treated on the O.D. The doubt at the moment is whether supplies of Swedish iron ore are adequate for sintered cast iron. Required a pure ore, as the material is never melted. Valve Seats. Cadillac do not use valve seat inserts. Say these run too hot. (Heron says, not if properly designed and inserted and probably the valves might do better to run a bit hotter). Cadillac say that with Wilcox-Rich valve lifters the seat damage is so small that inserted seats are unnecessary on car engines. Tappets. C.I. Feroxed tappets do an excellent job. Must send you a sample. | ||