The Ignition

T he electronic ignition for the SD1 is a Lucas part. Now I can see many people shivering, but honest. The Lucas system is NOT bad at all! Believe it or not. Many V8's run happily with the standard ignition system for thousands of miles without any problems. But although you don't have to care about changing points even an electronic ignition needs some attention The following items should be checked to keep your ignition in good working order. Check the plugs regularly and replace them when necessary Check the distance and adjust lightly smear Check the condition of the ignition leads and replace when necessary Check for play in the distributor Check the function of the advance unit Check the rotor and distributor cap Check the electrical contacts

HT leads diagram

Check the plugs regularly and replace them when necessary Normally the plugs last around 20,000 miles (30.000 km). A bit shorter for short distances or hot engines. The plugs are also a good indication of your car's health. So check the colour of the plugs when they come out. The colour should be light coffee brown for all cylinders.

1. Normal: Grey-brown deposits, lightly coated core nose. Plugs ideally suited to engine, and engine in good condition. 2. Oil Fouling: Wet, oily deposits. Fault: Worn bores/piston rings or valve guides; sometimes occurs (temporarily) during running-in period. 3. Heavy Deposits: A build up of crusty deposits. Light grey sandy color in appearance. Fault: Often caused by worn valve guides, excessive use of upper cylinder lubricant or idling for long periods. 4. Overheating: Electrodes have glazed appearance; core nose very white - few deposits. Fault: Plug overheating. Check: Plug value, ignition timing, fuel octane (too low) and mixture (too lean). 5. Lead Glazing: Plug insulator firing tip appears yellow or green/yellow and shiny in appearance. Fault: Often caused by incorrect carburation, excessive idling followed by sharp acceleration. Also check ignition timing. 6. Electrode Damage: Electrodes burned away. Core nose has burned glazed appearance. Fault: Pre-ignition. Check: Correct heat range and as for "overheating", above. 7. Carbon Fouling Dry, black, sooty deposits. Fault: Over-rich fuel mixture. Check: Carburettor mixture settings, float level, choke operation, air filter. 8. Split Core Nose: (may appear initially as a crack). Fault: Detonation or wrong gap setting. Check: Ignition timing, cooling system, fuel mixture (too lean). 9. Worn plugs Rounded electrodes with small amounts of deposits on the firing end. Normal color. Causes hard starting in damp or cold weather and poor fuel economy. Fault: Plugs left to long in the engine. Replace with new plugs of the same heat range. 10. Splashed deposits: Forms after long periods of misfiring. Fault: Deposits can loosen when normal temperatures are restored after a tune-up. At high speed the deposits flake off the piston and are thrown against the hot insulator, causing misfiring. Replace or clean the plugs. 11. Gap bridging Deposits lodge between the electrodes.The plug cease to fire resulting in a dead cylinder Check: Locate the plug and remove the deposits, check out point 3. 12. Mechanical damage: Can be caused by foreign object in the cylinder or the piston striking an incorrect reach (The plug is too long). Check: If other cylinders with same plugs are affected then it is an incorrect reach. Change the plugs for the proper type. Otherwise check with endoscope if the foreign object is still there and if there is damage to valves, cylinder liner....etc. Replace the plug.

Check the plug gap distance and adjust The plug distance should be around o,o..inch (.. mm) for a standard engine and ignition. If an uprated ignition has been fitted the gap can be increased to .. inch or .. mm. If you are running LPG and have the standard ignition the gap can be ... to ... inch .. mm Check the gaps with a feeler gauge, don't leave any grease on the plugs, this can cause misfiring. lightly smear Check the condition of the ignition leads and replace when necessary If the ignition leads are becoming of age (4 years or older) than the internal resistance can creep up reducing spark performance. If you have severe misfiring engine you might have a look under the bonnet when it's dark. I used to have a set of cables who where so bad you could see small sparks jumping from the cables to the engine! Using original ignition leads is better than going for a cheapo set of cables. The original Rover ignition leads are made by RISTS and very good. The RISTS brand is also indicated on cables. See the picture. If you want to go the expensive way then Magnecor has some excellent leads, but they are rather expensive, almoust double the price! So you might opt for this solution if you run very high revs frequently where every Volt counts. For standard everyday use there's not much need for it. Check for play in the distributor Check the function of the advance unit Check the rotor and distributor cap If the Lucas/Rover ignition system has a weak point then it's the distributor. It is a lot bigger than a 4 or 6-cylinder unit and it has a bit of a habit in developing small cracks when it get's older. When an engine is misfiring under high revs the distributor cap is one of the first suspects. They are not extremely expensive. When replacing the distributor cap also replace the rotor at the same time. Check the electrical contacts go!

HT Plug connectors Range Rover plug connectors although very good can be rather pricey. As an alternative you can use the plug connectors from a motorcycle. These are at as good and much cheaper. They come with various angles. Also see the picture above. Some NGK types are: Type SB05F LB05F XB05F YB05F Angle 0 90 102 120 Price (Euro) 2,95 2,45 3,95 2,95 Many more types are available, just ask a motorcycle dealer. Thanx to Paul Alting van Geusau for the information

SD1 Maintenance

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© A3aan oct. 2001