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).
Sparking plug selection and induction system development for a T.T. engine, including valve and carburettor modifications.
| Identifier | ExFiles\Box 82\4\ scan0384 | |
| Date | 1st October 1936 | |
| -7- Hs{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation}16/KW.1.10.36. Sparking Plugs. In 1934 we selected a sparking plug as being suitable for the T.T. engine of that year, this being the KLG-827. This plug was used in 1935 and again in 1936. Each year, plugs of varying heat resistance qualities were tried, and each time the 827 was found to be most suitable PART 4. Induction. The T.T. regulations demanded the use of standard size valves in the cylinder head. These were substituted as follows :- Development Head. Ex.22594. Inlet Valve 1.700. Exhaust 1.350. New Head. Ex.22594A. Inlet Valve 1.600) Exhaust 1.400) Standard production dimensions. Result. It will be remembered that a 1.450 exhaust valve was tried against 1.350 (throat dia.) and it should be added that no difference in B.H.P. could be noticed. Now with this latest modification of fitting standard valves, again no difference in power could be noticed. It is interesting to note curve No.S.3 (attached). A certain change in turbulence seems to have resulted from the modification by the necessary ignition advance curves. But in this case the Comp. Ratio and fuel were also changed. Curve No. S.4 shows the effect of fitting six single carburetters straight on to the inlet ports, thus cutting out an induction pipe altogether. The difference between curves (a) and (b) in themselves show that something might be gained by fitting carburetters with larger throttle bore: the carburetters used, however, were the largest available of their type, and then again they were the only type available, suitable for running six carburetters in line on our particular cylinder ports. | ||