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).
Performance graph comparing early versus late timing for a J1 head engine configuration.
| Identifier | ExFiles\Box 179b\3\ img161 | |
| Date | 28th January 1933 | |
| UNIT: C.9 J1 HEAD BENSPORT J1 S.9 COMP. RATIO 6.3:1 CAMSHAFT E.59139 (13 1/2") 2-1.375" SU CARBS ON SPECIAL PIPE BETWEEN 1x2 & 5x6 CYLS. BALANCED WITH SPECIAL 1.00" RESTN. CYL. HEAD: STANDARD E.56604. ① EARLY TIMING ② LATE TIMING R.M. 83 JAN. 28/33 | ||