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).
Extract from a letter by S. D. Heron discussing the corrosion of crank pin plugs on a Bentley car and suggesting modifications.
| Identifier | ExFiles\Box 150\1\ scan0034 | |
| Date | 1st August 1935 | |
| ETHYL EXPORT CORPORATION THAMES HOUSE, MILLBANK, LONDON, S.W.1 EXTRACT FROM LETTER RECEIVED FROM MR. S. D.{John DeLooze - Company Secretary} HERON. 1st August, 1935. The two corroded crank pin plugs from the Bentley car have been received and examination clearly indicates that the trouble is due to water. It appears to me that the diaphragm with holes in it is partly the cause of this trouble as this helps to keep the water segregated against the plugs. From examination of the plugs I also am of the opinion that Rolls use some kind of a scheme which results in sludge, water, etc. being segregated at the maximum radius of the hole in the crank pin. Segregation of sludge, water, etc. in the crank pin thus preventing it from passing to the bearings is an excellent idea from the standpoint of the bearings but hardly good for the plugs if the segregated material happens to be corrosive. If Rolls wish to continue to use aluminum for these plugs I would suggest that an anodic treatment be used and further, that the drilled diaphragm be abandoned. This diaphragm was, doubtless, used to center the plugs. Sketch is attached of a modified design which does away with the diaphragm but at the same time keeps the plug centered. The long hub shown on the sketch is to prevent the bolt bending due to centrifugal force. | ||