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 from The Light Production Co. Ltd. regarding connecting-rod pressure markings and potential piston failures.
| Identifier | ExFiles\Box 148\3\ scan0232 | |
| Date | 8th June 1937 | |
| - 2 - Messrs. Rolls Royce Limited. 8.6.37. Harvey-Bailey sent us from Mr. Geoffrey Smith's car, which had its connecting-rod attached, and there is very definite evidence of pressure on both boss faces and both faces of the small end, but the pressure markings on the small end are diagonally opposed, showing evidence of a slight misalignment of the faces in contact. There is no doubt that the pressure at some time has been considerable, since the markings of the rod go well below the surface of the boss face. There is no doubt that this phenomenon, if proved, would explain the failure of certain pistons in an engine when the others were apparently quite in tact, because presumably, the assembly of those units where the clearance is a minimum is accidental. We shall be very interested to learn the results of your tests to prove the point, but it would appear desirable that the drawing limits are altered in such a way as to permit a minimum clearance of .010", if such a procedure would not interfere with any other characteristic of the assembly which you must maintain. [Watermark: SNOWDON] Yours faithfully, FOR THE LIGHT PRODUCTION CO.LTD. [Signature] GENERAL MANAGER. | ||