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 discussing issues with cold knocking in Phantom engines and potential solutions.
| Identifier | ExFiles\Box 65\4\ scan0376 | |
| Date | 6th December 1927 | |
| X8050 POST 15 DEC 1927 RECEIVED IFW OY2.R.12.6.27 December 6th, 1927. Mr. Basil Johnson, Rolls Royce Ltd., London, England. (Copy for attention Mr. E.W. Hives) Dear Mr. Johnson: RE: CYLINDERS - SECTION 5050 We are still having trouble with cold knocking on Phantom engines, in fact practically our only troubles on imported Phantoms refer either to cold knocking or riding quality. We believe that we have located the trouble of cold knocking as due to insufficient lubrication of the bore. On the Silver Ghost this was overcome by connecting the extra oil to the pilot jet as well as to the accelerator, but as Mr. Hives pointed out sometime ago, the pilot jet is used for such short periods on the Phantom, that this connection is useless. We are, therefore, rather at a loss to find a reliable means of overcoming this trouble in our winter conditions, and are proposing to try on our experimental car, the operation of the extra oil by the carburation control so that when this is set on the extreme "strong" side, the extra oil valve will be opened. In the meantime we wish to suggest to Mr. Hives the possibility of an improvement through discharging the water from the water pump into the head instead of into the base of the cylinders. We notice that this is becoming an adopted practice in Europe as well as in the United States and that the following claims are made for it :- (1) Since the cooling of the cylinder barrel is by convection currents only, the cylinder warms up quicker, giving - Quicker elimination of cold knocking. Tending to cure dilution. Giving quicker warming-up after starting from cold. Tending to cure dry cylinder bores when starting from cold and - Tending to cure distortion due to projecting cold water against base of cylinder barrels. (Continued) | ||