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).
The failure of a Bentley high compression cylinder head (EX.16041) and proposed modifications for a new casting.
| Identifier | ExFiles\Box 86\1\ scan0120 | |
| Date | 7th February 1935 | |
| To RHC.{R. H. Coverley - Production Engineer} c. to CTS.{C. Trot Salt - Carburation} X219 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}25/KW.7.2.35. High Compression Cylinder Head for Bentley Competition Work. EX.16041. We have had a failure on the head to this. This is unfortunate as we were relying on this head to give us a figure for the enlarged inlet port, which by the single cylinder test should put our top power up by about 6 HP. We understand, however, that you have another casting and if we machine this to overcome the faults developed in EX.16041, and use the valve gear available, we should be able to get a quick test. Briefly, we should like to move the valve centres outwards as far as the casting will allow, machine away the turbulent lip except where it is needed to make a gasket joint, and bring back the compression ratio to 9.4 by machining the bottom face. We should be glad if you would make a modified drawing of EX.16041 to incorporate these features, and complete the head as soon as possible. Will you please cut up the existing head EX.16041 which has failed, in order that we can see if the coring between the valves on this particular head is defective. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||