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).
Proposal to modify the grinding of Wellworthy piston rings, with a comparison to Brico rings.
| Identifier | ExFiles\Box 16\1\ Scan177 | |
| Date | 21th October 1925 | |
| RMC. c. Hs.{Lord Ernest Hives - Chair} 4741 BY15/H.{Arthur M. Hanbury - Head Complaints} 21.10.25. WELLWORTHY RINGS. I would like to take some Wellworthy rings and modify the grinding of them slightly. My proposal is that we should make a fitting which will throw the ring out of square with its wearing faces by a matter of .002" in the depth of the ring. This means that we will turn a pair of conical faces on two separate pieces of steel to act as clamps. One of the pieces will be carried on a mandrel carefully centred, with the inclination referred to carefully produced. A loose sleeve should be available for centreing the ring before fully tightening it up by means of the second cone plate. The centreing ring is then removed and a light grinding guide run across the face of the ring to take away the raised edge resulting from the tilt we have put on the ring. The grinding would leave approximately .025" at the leading edge of the ring untouched. The result of this would be that when the ring is released and fitted into a piston, it would have a very slight clearance on its back edge acting as a wedge to force the ring up when the piston was rising, but the forward edge of the ring would act as a scraper when the piston was coming back. My opinion is that the Wellworthy ring is more accurate than the Brico. The Wellworthy has the faces of the sides of the rings square with the face that rubs on the cylinder wall, whereas it appears to me that in producing the Brico ring they have accidentally slightly coned the face of the ring which fits into the piston grove and coned it in such a way that the ring tends to touch on the leading edge of the piston when the piston is descending, thereby tilting up the back corner of the ring clear of the cylinder wall, as a result of the coning effect on the ring being destroyed when the ring is pushed into its groove. BY.{R.W. Bailey - Chief Engineer} Ry | ||