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 and modifications of pistons, cylinders, valves, and fittings.
| Identifier | ExFiles\Box 83\2\ scan0058 | |
| Date | 31th May 1937 guessed | |
| ( 3 ) PISTONS. New set of Aerolite Pistons and Rings. Identification M.12 supplied by Rm{William Robotham - Chief Engineer}/Mths.{Reg Matthews} Nos. 1, 5, and 6 pistons only completed the mileage. Nos. 2, 3, and 4, were damaged by broken valves and scrapped. No piston knocks were noted, and no trouble was experienced. CYLINDERS. LOP. EB.2715. Existing, complete to above LOP incorporating:- EB.2925 Cylinder Head deturbulated to LcC.5002. EB.2929 Cylinder Block. Cylinder barrels Nos. 1,2, & 3 radiused at base to Rm.{William Robotham - Chief Engineer}III. Nos. 4,5, & 6, as standards. Further mods. to Ex.22816 to suit front engine mounting. Repeated exhaust valve failure was experienced. The cylinder head was returned to Derby shortly before the end of the mileage, and it was found that the water passages were not to drawing. This allowed the valves to overheat. Leaks were experienced from No 6 circular water jacket plate on the O.S. of the block, also from the outlet pipe flange joint at the front of the head. VALVES & FITTINGS. LOP. EB.2708. Existing complete to above LOP. incorporating:- The following new parts:- 3 - Ex.23303 Inlet Valves S.65 in Nos. 1,4,& 5. 3 - EB. 2793 Inlet Valves S/SLV. in Nos. 8,9, & 12. 3 - EB. 2970 Exhaust Valves KE.965 (Stellited) in Nos. 2, 3, and 6. 3 - EB. 2970 Exhaust Valves S/SLV. (Not Stellited) in Nos. 7, 10, and 11. Clearance of .0015 - .002" in Nos. 7, 10, and 11. Valve Springs made by Tempered Spring Co. on Nos. 1,2,3,4,5,6,7, & 8. Painted red and green. American low carbon valve springs in Nos. 9,10,11, and 12. Painted green. The 3 EB.2970 Exhaust Valves S/SLV. were replaced by 3 EB.2970 Exhaust Valves KE.965. (Stellited) after 7.700 miles running. (continued) | ||