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).
Uneven engine cylinder lubrication, highlighting over-oiling at low speeds and under-oiling at high speeds.
| Identifier | ExFiles\Box 16\1\ Scan080 | |
| Date | 4th September 1915 | |
| R.R. 235A (800 H) (S.A. 353. 4-9-15) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 6970. -2- other bearings which intervene between them and their main oil supply pipe. In old engine with only slightly worn bearings it is frequently a job of some magnitude to tackle the overoiling question without putting the owner to the expense of having all the bearing taken up which one is loth to do knowing that as soon as they have worn a little the oiling is practically uncontrollable as before. Another important point is that at high speeds there is a much larger quantity of oil being thrown on to the cylinder walls from the big ends Nos. 1.3.4 & 6 than from Nos 2 & 5 with consequent uneven lubrication of pistons. It is a common thing to find that Nos 2 & 5 cylinder walls are overoiled at low speeds and under oiled at high speeds. I feel sure that we should have much better control of our cylinder lubrication with the oil fed to all the main bearings as suggested than is possible with the present method. I should like to remind you of what happened to the big ends ( always Nos 2 & 5) of the 4" by 6" engine when it was in my charge on the engine. Although this does not occur on our standard engine it is only because the centrifugal force is not so great with the shorter stroke engine but the tendency is there just the same and at the higher speeds which we may soon be getting with the lightened pistons and conn. rods this danger will increase." | ||