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).
And comparing valve sizes for various engine models, including EAC.10 and India 3.
| Identifier | WestWitteringFiles\R\January1928-March1928\ 114 | |
| Date | 6th March 1928 | |
| FROM E.{Mr Elliott - Chief Engineer} C. to HS.{Lord Ernest Hives - Chair} SY. ORIGINAL EAC.10. & INDIA 3. VALVE SIZES. X7060 X5060 (crossed out) In checking over the dimensions of LeC. 2509. I find that the exhaust valve dia. should be 1.700". This makes it that we have a 10% difference in inlet and exhaust valve dia. on EAC.10., the inlet being 1.9" - see Fig. 1. LeC. 2523. attached. EAC.14. has both valves 1.750". Falcon 10. has a 5% difference in dia. between inlet and exhaust, as also RR.H. 10% is the difference recommended by some authorities, but I am not sure that we have been wise in shewing the full amount for EAC.10. However we propose to leave it so unless we hear from you to the contrary. The alternative would be to make the valves 1.85 and 1.75 inlet and exhaust respectively, as in fig.3. Regarding India 3. it is hardly worth while having a smaller difference than .1" between the valve diameters, and this gives us 1.35 and 1.25, or an 8% difference shewn in Fig.3. These are the valves we are providing in the design of India 3. cyl. head. The present 20HP. valves are 1.2 dia. The tested larger valves are 1.4 dia., but these will not go into the existing cylinder centres. E.{Mr Elliott - Chief Engineer} | ||