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).
Results of a Brinell hardness test performed on an I/C G.M. cylinder block.
| Identifier | ExFiles\Box 132\4\ scan0076 | |
| Date | 1st June 1937 | |
| COPY 1124 HPS.{Horace Percy Smith - Experimental Factory Mgr} 1.6.37. G.M. CYLINDER BLOCK I/C Brinnel test in nine places on crown. Brinnel On No.3. cylinder...........216, 215, 216. Between No.3. and No.4........199, 203, 224. On No.4. cylinder...........229, 242, 224. Our brinell range for I/C cylinder blocks = 202 - 241. ------ | ||