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).
Modifications to cast iron cylinder head E.56604 to increase the compression ratio.
| Identifier | ExFiles\Box 14\3\ Scan079 | |
| Date | 9th December 1931 | |
| R.H.C. From Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} 2/MA. 9.12.31. CAST IRON HEAD E.56604 We understand that we have one of these heads finished machined and that by machining off the face of the cyl head until it is .062 thick as you once did on the 40/50 you can raise the compression ratio to just over 6-1. We should like to try the head like this as soon as possible. In the meantime we should like you to consider how you can alter the existing patterns and carbs to bring the compression ratio up to 6.5-1 with a normal thickness of bottom face. We could make a decision about casting a head like this as soon as we have had a run on the temporary one. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||