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).
Report discussing engine bore wear, piston rings, oil control, and crankcase breathing.
Identifier | ExFiles\Box 132\5\ scan0062 | |
Date | 11th March 1939 | |
-10- At this juncture this particular series of test was terminated because it was obvious that the desired result was not forthcoming in this way. It should be borne in mind that this was a serious attempt to accelerate bore wear conditions, and in reality, our measurable wear will be seen to be negligible. Referring back to Helmore's machine. We are trying to find out just how he divides up running time and stopping time, and what his actual temperature differences amount to. In this way we may get a little closer to the true relation-ship between "customers' conditions", and a practical method of accelerating bore wear. PISTON RINGS. If one gathers together the available information from various sources on rings, the result is a mass of confus-ion. As had already been said, this is the part of the job about which we know least. There are a few points on which there seems to be general agreement. (a) Plenty of oil should be thrown up the bores. It would be more correct to say, of course, that there is a right amount of oil which should be thrown up the bores, dependent on engine conditions. (b) Having fixed (a), control of the oil should be done by the rings. This is where most people probably fall down. There are also a few points about which different people have different ideas. But it must be remembered that it is probably as true of oil control on cylinder bores as it is of induction systems; that is that these auxiliaries have to be "tailored" to their particular engine. (a) Pegging the rings; we used to peg our rings and it is a fact that blow by was excessive. Our crankcase breathing in those days was done by connection to the induction system, and one of the difficulties of this method of breathing the crankcase was to provide an efficient baffle, to control heavy oil vapours, which came out of the rocker cover under pressure. | ||