Setting Ignition Timing on a Series Land Rover
The ignition timing controls the exact moment that the spark takes place across the spark plug electrodes. The timing of this is critical for efficient engine operation; maximising power and affecting fuel consumption. However, the size of the contact points gap can also affect the timing of the spark; so it is important to set the points gap accurately to the correct value before setting the ignition timing.
The general procedure for setting the ignition timing on a Series Land Rover is the same as for many classsic cars. Firstly, take out the spark plug nearest to the radiator (No. 1 plug), ensuring that its surroundings are clean and no debris falls into the cylinder during its removal. Ideally, the engine should then be turned over with the starting handle until pressure can be felt on your thumb when placed over the spark plug hole. If no starter handle is available then the Land Rover can be pushed backwards on level ground in reverse gear - easiest with all the plugs removed. An alternative method is to remove the rocker cover then turn over the engine until both valves on number 1 cylinder are closed. At this point the engine is close to the point where the spark would normally be generated.
The timing marks for Series Land Rovers vary according to the model type and year:
A pointer under an inspection plate on the flywheel cover (early engines)
The 3 lines represent TDC (top dead centre), 3 degrees BTDC and 6 degrees BTDC
A 3-pronged pointer mounted on the timing cover and a notch in the crankshaft pulley (later engines)
The 3 prongs represent (viewed from the front) TDC (top dead centre), 3 degrees BTDC and 6 degrees BTDC
Ignition timing settings for each engine
1.6litre engine: 15deg BTDC
2litre engine: 10deg BTDC
2.25litre: 7:1 engines 6 deg. BTDC; 8:1 engines 0 deg. TDC; 8:1 (emission controlled) 6 deg. ATDC
2.6litre: 7:1 engines 6 deg. BTDC; 8:1 engines 2 deg. ATDC
Some distributors have a knurled knob for fine timing adjustment and this should be set in the middle range. Next take off the distributor cap and loosen the distributor clamp bolt. Remove that leads to the distributor at the coil end then connect a multi-meter set to read d.c volts, or alternatively, a 12volt bulb between the coil terminal and a good earth point. With the ignition turned on, rotate the distributor very slowly in the direction of rotation of the rotor arm until you see a reading on the multi-meter(or the bulb lights).
Tighten the distributor clamp bolt. The static ignition timing has now been set.
Truly correct ignition timing varies with vehicle condition so it is best to test drive it. Try accelerating between 30-50mph(50-80km/h) and listen carefully for engine ‘pinking’ - a characteristic metallic sound. If you hear it then retard the ignition 1 degree and test again until no ‘pinking’ is heard. Other causes of the ‘pinking’ can be a worn distributor(check the central shaft for any sideways movement), a poor grade of petrol or carbon deposits inside the cylinders (remove the spark plugs and inspect).
Previous homepages devoted to the ignition system were July 2010 February 2011
(To see other previous homepages visit the Homepage Archives link)