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).
High oil consumption, comparing results from steady and fast runs, and the effectiveness of different piston rings.
| Identifier | ExFiles\Box 146\2\ scan0248 | |
| Date | 23th June 1937 | |
| SrI/ET.23.6.37 - 4 - tion. We note that the cylinder bores were not in bad condi- This is interesting. N°7 (in the paragraph "Work carried out") - This is rather interesting, the engine never having been dismantled in our shops. N°9 - We noticed that the 25/30 crankcase breather had been fitted. Also that the cover rocker breather had been blanked off. So far, this has not, evidently, given the de- sired effect. What speed does the term "steady run" imply in this particular case ? It must have been very low for the oil con- sumption registered to be 1800 M.P.G. It is interesting to note that, as soon as the car was given a "fast run" (what speed does this represent?), the oil consumption for 200 miles became 980 M.P.G., which is approximately 50% of the "steady run" figure. Personally, I think it is high time that somebody came over here to investigate this oil consumption question with us and, until that is done, I am satisfied that no efficient results will be obtained. As you know, our conditions compare in no shape, form or manner with yours in England and our experience, which certainly must be taken in consideration, tends to prove that, even when we change cylinder blocks, piston rings and pay great attention to the odds and ends of the job as per CWH.'s instruc- tions, we do not obtain anywhere near the results we are informed are obtained by Kingsbury when they adopt similar methods. Furthermore, there is something uncanny about this oil consumption question, inasmuch as my car, which was decidedly on the high side from an oil consumption point of view, has recently turned the corner and now my oil consumption is as low as can be expected on the Continent. "L" section rings were fitted to this car some months back, and since they were fitted I have covered 20.757 Kms. Does this mean that one has to run in piston rings until the car is nearly worn out before they are bedded in. If so, surely we must do something about it. Sr. h | ||