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).
Valve and cylinder head specifications for the B-21 Le Mans Unit.
| Identifier | ExFiles\Box 90a\4\ Scan230 | |
| Date | 21th May 1936 | |
| X262 To RRC. Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}14/KW.21.5.36. B-21 - Le Mans Unit. Following our report on valve pocketing we have tried 1.45" dia. exhaust valves and find that they are no definite improvement over the 1.35" dia. valves in this respect. We have decided therefore to stick to the small valves as we have not had a failure, whereas 2 large valve heads have broken. This completes the specification of the valves etc. irrespective of which head is used in the actual race, and is as follows :- Rs.{Sir Henry Royce's Secretary}276 - 1.35" dia. exhaust valves. Ex.20968 - Inlet valves in KK-965. Rm.{William Robotham - Chief Engineer}53 - Valve springs, not enamelled. Rm.{William Robotham - Chief Engineer}133 - Bottom valve spring washers. Rm.{William Robotham - Chief Engineer}134 - Top " " The programme for the cylinder heads is as follows. Ex.20943 head is being prepared and will be fitted to B-21. The head Ex.22594 which has a lower spark plug position and improved water passages to be completed as soon as possible for endurance on B-3. A second Ex.22594 head to be made so that if the pocketing shows any improvement by the endurance on B-3 we have a similar new head which will be fitted into B-21 as soon as possible. Hs{Lord Ernest Hives - Chair}/L.H.Swindall. | ||