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).
List of modifications to resolve sparking plug fouling and carburation issues.
| Identifier | ExFiles\Box 50\3\ Scan174 | |
| Date | 30th August 1921 | |
| Contd. -3- HS{Lord Ernest Hives - Chair}5/LG30.8.21. 3. Fouling of sparking plugs:- By carrying out the following modifications - 1. Produce a throttle identical to the present as regards the contour on the inside. With an exahsut jacket completely surrounding it as shown on N.scheme. 2. The diameter of the pipes leading to and from the throttle should be ¾" dia. bore. 3. The return exhaust pipe should pass under the crankcase and join up to the rear chamber of the front silencer. 4. The butterfly throttle should be fitted to the exhaust pipe as shown on LeC. The valve should be made of cast iron or some material which will not be effected by the heat. 5. The butterfly valve should be made 3/8" thick - this forms a permanent baffle in the exhaust pipe which can be used without loss of power because of the ¾" pipe which has been added. This thick valve also allows a big dwell on the opening of the valve. 6. The piston in the throttle should have taper slot and spring to ensure it closing for starting. 7. Small pressings should be soldered to each induction pipe branch to form a weir. 8. A chamber should be formed and welded to each [handwritten] exhaust [/handwritten] down pipe - [handwritten] & [/handwritten] pipes from each 3 branches should be fitted to drain petrol into them. [handwritten] inlet [/handwritten] If the above modifications are carried out we are sure that your carburation troubles will disappear. This information is the best we can do for you - when it comes to LeC. design and models I should not like to promise. We also recommend that in arranging the control for the butterfly valve, consideration should be given that the adjustment can be easily altered for summer and winter conditions. A very good job should be made of all the connections contd;- | ||