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).
Issue of piston ring knock in pre-war engines after an overhaul.
| Identifier | ExFiles\Box 16\1\ Scan163 | |
| Date | 29th August 1923 | |
| COPY. To BJ. from Hm.{Capt. W. Hallam - Head Repairs} Hm{Capt. W. Hallam - Head Repairs}/NRC{N. R. Chandler}1/W29.8.23. Re Piston Ring Knock. - Pre-War Chassis. Some pre-war engines develop a knock or click in the piston rings, usually a thousand or two miles after the cylinders have been re-ground and fitted with new pistons and rings. On dismantling we usually find one or more rings partially stuck in their grooves with carbon, and the only remedy we know is to slightly ease the ring in it's groove. This knock only occurs on a small percentage of the engines we deal with, and there has not been in a single instance any evidence of the rings being fitted too tight, or in any way differing from the large majority which do not develop this knock. We are experimenting with a new cast ironpiston, having narrow rings similar to those used on the post-war engine, meanwhile there is always the possibility that this knock may develop on any pre-war engine fitted with the deep standard ring for cast iron pistons. This knock usually develops within the first few thousand miles after overhaul, or not at all. We suggest a Policy order number for curing this knock, as the work does not appear to be fairly chargeable to either A.T.D. or R.D.W. Kindly let us know if you agree. Hm{Capt. W. Hallam - Head Repairs}/NRC.{N. R. Chandler} | ||