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).
Limitations and alternatives for cylinder head designs, including pent-house and ramp heads.
| Identifier | ExFiles\Box 134\2\ scan0012 | |
| Date | 26th April 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/Smth.15/KW. 26.4.35. With the standard head, 1.500" is probably the useful limit to the inlet valve diameter. A pent house head would require two camshafts to allow access to the central sparking plug, and offers no better valving than the ramp head unless radial valves are used, which is out of the question owing to the complication of the valve gear. We are left, then, with the ramp and the high power heads as the only alternatives. We cannot get anything like as good valving with the ramp as with the other unless we use two inlet valves. Such a head, however, would appear to be bad for detonation owing to lack of forced turbulence, and we think that this point should be tested as soon as possible so that we can settle the question conclusively. If the three valve ramp won't work, then we are left with the high power head as being the only head left for us to adopt. When you have tested the aluminium high power heads together with the schemes we discussed recently for inclining the inlet valves and narrowing the combustion chamber, we shall have the complete story and be able to make definite recommendations. HS{Lord Ernest Hives - Chair}/Smth. | ||