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).
Technical query comparing British and American manufacturing methods for engine components like rings, pistons and cylinders.
| Identifier | ExFiles\Box 148\3\ scan0163 | |
| Date | 13th October 1936 | |
| -5- Forming of Rings. Do you consider that more reliable rings can be produced by heat forming against hammer forming? We notice that practically no American ring is hammered. What are the disadvantages of hammering, if any? Ring Casting. We also notice that in America you use individually cast rings. What are the advantages over the British centrifugally cast rings? We have done only a little work with our high pressure rings, but so far we have not found much difference in the individually cast ring and the centrifugally cast ring. We noticed, however, that when using the individually cast ring on one occasion, the ring appeared to wear more rapidly than the centrifugally cast ring, this of course is only an isolated case and may mean nothing at all. There is of course only one firm in this country producing rings from individual castings; with this exception, every other firm uses centrifugally cast rings. Do you consider that you can cast successfully alloy irons by the individual method? Piston Type. Do you consider the trunk type of piston to have better oil controlling properties than a split skirt type? What effect have these types of Piston on cylinder wear, is the split skirt better or worse than the trunk type. These facts of course relate to aluminium alloy pistons. Cylinder Wear. What effect have high pressure rings on cylinder wear? We should think that with rings giving a good oil consumption, which of course would mean that the top ring would be running fairly dry, the high pressure would give rise to excessive wear. The scraper ring of course is different with the quantity of oil there: there is not much danger although as we have previously stated, we have not had much success by increasing the scraper ring pressure. | ||