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).
Tests on cracked valve seats in Wraith cylinder heads.
| Identifier | ExFiles\Box 10\3\ 03-page181 | |
| Date | 1st October 1938 | |
| 654. Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} Da.{Bernard Day - Chassis Design} RHC.{R. H. Coverley - Production Engineer} Rm{William Robotham - Chief Engineer}1/R.1.10.38. CRACKED VALVE SEATS - WRAITH. The attached list covers all the cylinder heads running in the Exptl. Dept. It will be seen that under road conditions valve seat cracks of any kind on Wraith heads have been limited to one car, i.e., that being run by Mx.{John H Maddocks - Chief Proving Officer} Our experience with the small valve head is, however, limited. Accelerated bench tests show that the Wraith head is fundamentally worse for cracks than the old type 25/30 head, to which we are proposing to revert. Tests continue. Rm.{William Robotham - Chief Engineer} | ||