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).
The ignition of weak fuel mixtures and planned tests on spark plugs and ignition systems.
| Identifier | ExFiles\Box 163\7\ img335 | |
| Date | 23th February 1940 | |
| To:- Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c to Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies} c to Rm{William Robotham - Chief Engineer}/GTS. c to EV.{Ivan Evernden - coachwork} 6013 Spare Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}4/DT.23.2.40. ------------------ DISCUSSION ON IGNITION OF WEAK MIXTURES - WORKS 17/2/40. PRESENT: Rm{William Robotham - Chief Engineer}, Rm{William Robotham - Chief Engineer}/RC{R. Childs}, Rm{William Robotham - Chief Engineer}/GTS., Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} The present position is that if a Carburation System is set to weakest possible mixture consistent with freedom from flat spots with clean plugs, after approximately 2,000 miles flat spots become evident due to deterioration of the plugs. It was decided that tests should be carried out on the following lines:- (A) Attempts to find a plug which will not change its characteristics as follows:- 1. Test K.L.G. platinum point plugs in transport car. 2. Test Champion L.B.8 in transport car. 3. Order A.C. K.D.7 plugs as recommended by A.C. for R.R. cars. 4. Ask Champions for cooler running plug. (B) Attempts to make ignition system cope with deteriorated plugs by the following - 5. Rig up additional battery and switch so that voltage applied to coil can be both increased and decreased to see whether this affects trouble. 6. Rig up two coils in parallel to increase energy available at spark. 7. Increase distributor rotor gap. (C) Attempts to determine cause of changed plug characteristics. The alternative theories are at present:- (a) that a film of oxide forms on the plug points and increases plug voltage, and (b) that the insulator acquires a deposit which forms a leak to earth. 8. Obtain a faulty plug of the detachable type and cont'd | ||