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).
Procedure for servicing main bearings during a decarbonization at 10,000 miles.
| Identifier | ExFiles\Box 146\1\ scan0158 | |
| Date | 3rd January 1938 | |
| - 2 - accumulated since my insistence on Lp{Mr Lappin}'s car being brought back for re-examination. With reference now to your suggestion that at 10,000 miles, when you give the first decarbonizing, that the main bearings should be let up by stepping the shim or liner, whilst I do not think this makes a really sound job, I believe that it could be made sufficiently good to ensure the car running without further trouble from engine thud up to the mileage at which you give a bottom decarbonising i.e. 20,000 miles, but to achieve this object it would be necessary to remove the upper half bearing by turning it round the crank until it could be removed, the object of this being to ensure the deletion of the oil between the upper half bearing and the crankcase - a spray of paraffin could then be used to clean the housing for the upper half bearing from oil. If, having done this, the bearing was then 'let up' until no perceptible slack was left, I believe you would obtain a condition of things for a bearing sufficiently durable to safely last until the bottom decarbonising period arrives. GWH.{George W. Hancock - Head Chateauroux} is not in agreement with me on this particular point, as he says a really good job cannot be obtained without taking the engine out of the chassis, as it is extremely difficult for a man to work under a car with the amount of oil that is present and achieve a reasonable job. I am inclined, however, to think that your scheme, if the above procedure could be followed, would make a really reliable job. Obviously you cannot get nip, and until we are in the position to give nip by fitting new bearings, with the further safeguard of a white metal bearing in No.7 we cannot hope to make a really 100% job. BY BY.{R.W. Bailey - Chief Engineer} | ||