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).
Piston knock issues in Phantom II chassis and potential solutions.
| Identifier | ExFiles\Box 47\3\ Scan057 | |
| Date | 29th April 1931 | |
| File X4117 To Wor. {Arthur Wormald - General Works Manager} From Hs {Lord Ernest Hives - Chair} /GWH. {George W. Hancock - Head Chateauroux} Hs {Lord Ernest Hives - Chair} /GWH. {George W. Hancock - Head Chateauroux} 4/KT. 29.4.31. X7040 (1) Piston Knocks. Hs. {Lord Ernest Hives - Chair} and Rm. {William Robotham - Chief Engineer} are of the opinion that extra oil to the cylinders is a help, but they are of the opinion that the longer skirt piston should reduce the tendency of piston knocks. Hd. {Mr Hayward / Mr Huddy} is of the opinion that Phantom II pistons are an improvement over Phantom I and the fitting of the extra oil does not justify the extra cost. Copy of memo. received from Cricklewood - N/W. Hs {Lord Ernest Hives - Chair} /GWH. {George W. Hancock - Head Chateauroux} BRL/WG. {Mr Gill - Financial Director} 20.4.31. re Piston knocks on Phantom II chassis. ------------------------------------- With reference to your Hs {Lord Ernest Hives - Chair} /GWH {George W. Hancock - Head Chateauroux} 4/KT.16.4.31. we at N consider that piston knocks on Phantom II cars are very much inkeeping with those on the later Phantom I cars. By this we mean that in most cases when the mileage is getting on towards 20,000 piston knocks are very audible, when we have to advocate what is known as the R.20 decarbonisation which of course costs twice as much as an R.10. We get many complaints of piston knocks cold on Phantom II's, and if the mileage does not justify the R.20 we endeavour to re-assure the owners with a view to postponing attention until the R.20. We do feel that the introduction of the extra oiling device would go a long way towards curing this trouble as it appears to us that damage is done when starting up from cold, but for piston knocks it would be possible to give a Phantom II engine two or even three R.10 decarbonisations, and thereby we should save considerable expense to the owners, especially as so many of them nowadays are inclined to grumble at our charges. Br. {T. E. Bellringer - Repair Manager} ------------------------------------- By. {R.W. Bailey - Chief Engineer} states that it is impossible to incorporate the extra oil to the present cars. The longer skirt piston is to be incorporated on the L.H. immediately. There will be 50 sets of the short pistons to be used up on N. series R.H. The longer skirt piston will then be incorporated. These cars will have the extra oil and we are satisfied that it will | ||