THE coil ignition equipment is provided with. an automatic advance mechanism, which relieves the driver of the necessity of constant adjustment of the hand ignition control. Its advantages are particularly evident when accelerating, and during hill climbing, the danger of pre-ignition knocking or "pinking" being very much reduced.
The device is housed in the distributor unit, and it consists of a centrifugal!/ operated mechanism by means of which the ignition is advanced in proportion to engine speed. Very little attention is needed to keep the ignition equipment in first-class condition. We advise that it is inspected occasionally, and the following instructions on lubrication, cleaning and adjustment should be carried out.

Distributor and Contact Breaker Unit.

Occasionally remove the distributor moulding by pushing aside its two securing springs. See that the electrodes are clean and free from deposit. If necessary, wipe out the distributor with a dry duster and clean the electrodes with a cloth moistened With petrol. Also see that the carbon brush in the centre of the moulding is clean and moves freely in its holder.

Distributor and Contact Breaker Unit.

Next examine the contact breaker ; it is important that the contacts are kept free from any grease or oil. If they are burned or blackened, they may be cleaned with a fine carborundum slip, or if this is not available, with very fine emery cloth and afterwards with a cloth moistened with petrol. Care must be taken that all particles of dirt and metal dust are wiped away. It is possible that misfiring may be caused if the contacts are not kept clean.

Do not attempt to clean up the points if they become rugged, but have them attended to by a skilled mechanic.

Contact Breaker Gap.

The contact breaker gap is carefully set before leaving the Works, and will probably only need adjustment at very long intervals. It is not advisable to alter the setting unless the gap varies considerably from the gauge. If adjustment is necessary, turn the engine to the position in which the maximum opening of the contacts is given and then, keeping the engine in this position, slacken the locking screws in the contact breaker base. Then move the bracket carrying the contact until the gap is set to the thickness of the gauge. Afterwards tighten the locking screws. It is advisable to check the gap again to ensure that no movement has taken place.

Lubrication.

The distributor spindle bearing is lubricated by means of an oiler which requires a few drops of oil every 1,000 miles. Every 3,000 miles, give the cam the slightest smear of vaseline and place a single drop of oil on the pivot on which the contact breaker works. Withdraw the rotating arm from the top of the spindle by lifting it off, and add a few drops of thin oil to the top of the spindle. Do not remove the screw exposed to view, as there is a clearance between the screw and the inner face of the spindle through which the oil passes to lubricate the automatic timing control. Take care to refit the arm correctly and to push it on to the shaft as far as possible.

Coil.

The coil unit requires no attention beyond seeing that the terminal connections are kept tight, and the moulded coil top is kept clean.

Renewing High Tension Cables.

When the high tension cables show signs of perishing or cracking, they should be replaced. Use only 7 mm. rubber-covered ignition cable for all high tension leads. To connect up the 7 mm. cable to the distributor or coil terminals, thread the lead through the terminal nut, bare the end of the cable about 1/4in., pass it through the washer and bend back the strands. Tighten the terminal to make a good connection.

Method of Fitting
Cable Terminals.

Ignition Faults.

When the engine will not fire, or fires erratically, the trouble may arise from the carburetter, or petrol supply and not the ignition. A partially choked jet, an incorrect petrol level, or air leaks into the induction system may be the faults. Equally, sooted plugs can be suspected, when dismantling and cleaning them will remedy the trouble. If the battery has run down, or its terminals have worked loose, quite obviously there will be no spark, and the same resuits can be expected if the distributor electrodes and contact breaker have been neglected and are dirty.

The coil can be tested by removing the cable from the centre socket on the distributor cover, and holding the end of this cable about 1/4 inch from some metal part of the car, while the ignition switch is on and the engine is turned. A strong and regular spark will result if the coil is in order. Clean the top of the coil, and ensure that the terminals are tight before making this test.

To test for short circuits in the low tension wiring (the cables from the switchboard to coil, coil to distributor, and distributor to chassis) which would equally cause irregular running, have the engine turned while the ignition is switched on, and watch the ammeter reading. It should rise and fall as the contact breaker points close and open. This test will also indicate if the contact breaker is functioning correctly. If the contacts remain open, or do not fully close, the reading will not fluctuate.

If the high tension cables from the distributor to the plugs are not securely attached to the distributor, misfiring may occur. Or if the rubber insulation on the cables shows signs of perishing and cracking, there may be leakage of the current giving rise to the same symptoms. Renewing the cables is then the remedy.

If, after verifying these points, the trouble remains undiscovered, the equipment should be examined and tested by the nearest service depot of the makers.
 

Sparking Plugs.

The sparking plugs with which the "Ten " is fitted are K.L.G., type 777. The gaps between the firing point of the central electrode and the earth points are set at .015 to .018 of an inch. Too wide a gap would cause misfiring, especially at high speeds, and under heavy pulling at lowspeed with an open throttle, while a too small gap causes poor idling.

After the first thousand miles it may be necessary to clean the plugs, because an excessive amount of oil is sometimes used and this causes a deposit of carbon on the interior insulation of the plugs. Type 777 is a three-piece plug—the gland nut is a separate component. To clean a plug, the insulated centre A must be removed from the plug body C by unscrewing the gland nut B. When B is unscrewed the central electrode may be withdrawn. Wipe the lower mica insulation carefully, with a petrol-soaked rag. If the carbon deposit is hard, soak the electrode in petrol for an hour or so, this will soften the carbon. The mica insulation D should be thoroughly cleaned and polished, and the central electrode scraped clean.

Scrape out the inside of the body and clean the earth points. Wash the plug body in petrol, and dry it. To reassemble, see that the internal washer is in place before inserting the electrode. Tighten the gland nut to secure gas tightness, reset the earth points E to .015—.018 in. To do this it may be necessary to bend each earth point toward the central electrode.

The central electrode must not be levered toward the earth points.

If the sparking plug washer has been completely flattened, replace it with a new one ; most garages stock them and they are cheap.

A Insulated Centre.   D Mica Insulation.  B Hexagonal Gland Nut.  C Plug Body.

Poor grade oil, improper carburetter adjustment, low grade petrol, excessive use of choke, faulty cables, distribution points out of adjustment—all these may cause fouled sparking plugs. Sparking plugs should be renewed every 10,000 miles.

Ignition Warning Lamp.

When the engine is stopped, unless only momentarily, the ignition switch should always be turned to the "OFF" position so as to prevent the battery being discharged by current flowing through the coil winding. A warning lamp is provided in the switchbox, which gives a red light when the ignition is "on" and the engine is stationary, thus reminding the driver to switch off. Should the bulb of the warning lamp fail, it can be withdrawn from its socket when the small cover plate, holding the red glass, is unscrewed. The replacement bulb should be a 2.5 volt, .2 amp. screw cap type (No. 252 M.E.S.),
 

Timing the Ignition.

First remove the floorboard over the clutch casing. The engine is then turned by the starting handle until the compression of No. 1 cylinder is felt, then remove the sparking plug of that

The Flywheel Timing Mark for the Ignition.

cylinder. While the engine is turned slowly, watch the flywheel cover through the inspection hole until the line marks 1—4, indicating the top dead centre positions of pistons No. 1 and No. 4 become visible.

Correct Timing Position.

The engine should be turned until this line is approximately 1 inch before the vertical position. This is the correct position for setting the ignition timing. Now turn to the distributor.

Remove the cover by springing back the two securing springs. The clamping screw in the distributor will now be "free," and should be turned slightly to the right or left until the contact breaker just begins to open. The clamping screw should now be tightened again. It is in this position that the pointer on the securing arm will point approximately at the centre of the graduations, which will be found on the side of the distributor body.

Refit the distributor cover and secure in its proper position by the two springs. A small projection on the casing fits in a recess near one of the clips to secure the distributor cover in its correct position.

DIAGRAM OF POSITIONS OF
CHANGE SPEED LEVER.