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).
Investigation into high oil consumption issues in 4 1/4-litre Bentley Cylinder Heads, finding them to be hollow.
| Identifier | ExFiles\Box 131\4\ scan0084 | |
| Date | 9th March 1937 | |
| 1113 E . from Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} By.{R.W. Bailey - Chief Engineer} RHC.{R. H. Coverley - Production Engineer} Rm.{William Robotham - Chief Engineer} Kingsbury - 9.3.37. 4 1/4-litre Bentley Cylinder Heads. We have been investigating a high oil consumption job here, and in doing so we checked the cylinder head base for being flat. We found that it was hollow in the centre to an extent of .007". Another 4 1/4 head was checked and this one was found hollow to the extent of .006". Is this due to distortion after fitting, as one cannot imagine that the machinery leaves it so much out. The following is a rough sketch of the heads:- Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} [Sketch of a cylinder head cross-section shown to be concave] .009 Bolt holes. .007 .009 | ||