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).
Letter to The Light Production Co. Ltd. concerning piston ring sideways clearance.
| Identifier | ExFiles\Box 87\2\ scan0218 | |
| Date | 28th July 1936 | |
| x236 Exptl. Dept. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}21/KW. 28th July, 1936. C.H. Brooks Esq., The Light Production Co.Ltd., 60/66, Rochester Row, Westminster, LONDON, S.W.1. Dear Mr. Brooks, Piston Ring Sideways Clearance. For some reason the correct sideways clearance on piston rings which we have established for Rolls-Royce pistons is about 50% greater than your drawing clearances for Aerolite pistons. We do not know how you arrive at your clearances, but in our own case the dimensions utilised are the minimum that have been found satisfactory to prevent rings sticking in the grooves. We are wondering whether this ring clearance can have had anything to do with the occasionaly cases of piston seizure experienced. Another feature seems to be that the ring gap is at present on the low side, and if all the limits go the wrong way it would seem possible for the end of the ring to abut, particularly if the engine is driven away rapidly from cold. Obviously we have no very definite evidence on this subject, but would like you to consider the matter to see whether you think the standard we are at present using is the best. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||