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 Maurice Olley discussing the prevention of cold-knocking and cylinder wear by coupling extra oil to the pilot jet.
| Identifier | ExFiles\Box 74\2\ scan0091 | |
| Date | 16th October 1925 | |
| X4387 ROLLS-ROYCE OF AMERICA, INC. SPRINGFIELD, MASS. Oy1-E-101625 October 16, 1925. Mr. E.{Mr Elliott - Chief Engineer} W. Hives, Mickleover, Near Derby, England. Dear Hives: Re Extra Oil Coupled to Pilot Jet Referring to my letter of yesterday, we have come to the conclusion after 23,500 miles on our first L.H. car with extra oil coupled to pilot jet, that this is valuable not only to stop cold-knocking but to prevent cylinder wear. The cylinders and pistons on this car were in the best condition we have ever seen. The bores were better than new, having a highly-polished mirror finish. There was little measurable wear and the engine had never knocked cold. The reverse of the picture is that Hup had to cancel and replace their aluminum pistons because the bores and pistons were scored through the use of a choke in starting washing the oil off the cylinder walls. Aluminum pistons are naturally worse under these conditions because they warm-up slower than cast-iron. We have the idea that the extra oil pipe can be carried in the crankcase as a companion of the main oil pipe in its seven bronze bushes and with jets shooting upward into the lower end of the cylinder bores. We are putting extra oil operation with the pilot jet, on a number of owners' cars not so fitted, to stop cold-knocking. Yours very truly, Maurice Olley MO/E | ||