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).
Letter from a Chief Engineer at Buick Motor Company detailing experiences with engine components.
| Identifier | ExFiles\Box 133\4\ scan0006 | |
| Date | 12th December 1934 | |
| (2) Dec. 12, 1934. (6) a.{Mr Adams} Several years ago we did considerable work on the prevention of exhaust valve sticking, and we found that by copper plating the valve stems (to prevent scoring when new) and by careful design of the water jacket around the guide, we could run exhaust valves with clearances as low as .001" with a marked reduction in wear, and, consequent greater mileage, to the point where oil leakage down the stem was sufficient to cause sticking. We have not gone as low as .001" in production, however, but are working to a minimum of .002" instead of .0035" as was our previous practice. b. We have had no indication whatever of a need for special valve seat inserts. Our present 40 series despite its higher M.E.P. is the best job we have ever built in this respect. I believe we have much less seat distortion when the head is bolted in position, and also very much less distortion due to heat than the L-head people have, and, we have attributed our success to this. (7) The heat valve on the 40 has been quite satisfactory as regards both life and rattle. I am enclosing prints of the parts and would call your attention to the design of spring stop for the "closed" or "heat on" position. This is the only stop we have found which will be satisfactorily quiet in operation. The material specifications are given on attached sheet #2 of Buick steel specifications. We have had very satisfactory results from these materials and have always got into trouble when we attempt any other specifications. You will find that it is necessary to use a carbon rod to make a satisfactory weld between the heat valve and the shaft. This point has to be watched in production to make certain that the welder gets a real weld and not just a ball of metal piled up on the surface. (8) We have not experienced any troublesome flywheel flutter but believe that our 40 design is about as narrow as we dare go on rear main bearing width without getting into this trouble. (Signed) C.A. Chayne, Asst. Chief Engineer BUICK MOTOR COMPANY. | ||