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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).
Testing of nickel molybdenum and nickel chrome molybdenum alloys to address cylinder head seat cracking and cylinder bore wear.

Identifier  ExFiles\Box 132\4\  scan0175
Date  6th October 1938
  
1124

To RHC.{R. H. Coverley - Production Engineer} from Rm.{William Robotham - Chief Engineer}
c. HPS.{Horace Percy Smith - Experimental Factory Mgr}

c. Hs.{Lord Ernest Hives - Chair}
c. By.{R.W. Bailey - Chief Engineer}

Rm.{William Robotham - Chief Engineer}1/MH.{M. Huckerby}6.10.38.

CRACKING OF CYLINDER HEAD SEATS.

In order to determine whether the material can be a predominating factor with regard to valve seat cracking, we should like to try as soon as possible, some small valve cylinder heads made in nickel molybdenum alloy. This is the alloy recommended in RHC{R. H. Coverley - Production Engineer}/Vs.{J. Vickers}1/JT.9.8.38.

We should require 3 cylinder heads, one of which we should like machining as soon as possible, and if this shows promise we can make repeat tests on the othertwo.

With regard to cylinder bore wear we have information from Ll. Smith in America, that the nickel chrome molybdenum alloy is widely favoured over there as being the best material for reduction in bore wear. we should like 5 blocks to be cast and finish machined in this alloy, and handed to GWH.{George W. Hancock - Head Chateauroux} to be fitted to cars which require reboring after a very small mileage. We will run one block ourselves on the test bed, to make sure that the rings bed down, etc. etc.

If the blocks seem to be an improvement in customers' hands we can swing over on production without a very large increase in cost (less than 2/- a block).

We are continuing with our test bed wear experiments, but we feel it may be a very long time before we get results the benefit of which can be passed on to the customer. If we get some owners running on nickel chrome molybdenum we are at least following the procedure on the subject which has been found best in America.

Rm.{William Robotham - Chief Engineer}
  
  


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