Setting the ignition timing on a 2CV is a routine service item, forming part of the D (anual) service. It will also need doing if the points are replaced or adjusted.
Setting the timing requires the use of a specialist tool – in this case a 6mm rod. I inherited a bent nail which does the job admirably.
This fits through a hole in the engine block on the near side under the inlet manifold.
The bend in the tool is required as the dipstick tube blocks straight access to the hole. The tool will come out through the hole and present to the face of the flywheel.
Rotating the engine will turn the flywheel until a hole in the body of the wheel will align with the tool. Use the tool to lock the flywheel at the timing point and paint some alignment marks on the flywheel and a static part of the engine. When painting the line don’t forget to take account of parallax.
Now remove the tool – this is important as you will need to rotate the engine to set the timing.
If you haven’t done so already, remove the fan to gain access to the points box. You won’t need to open it for this job.
Slacken off the nuts either side of the box and free the box, it might well need a bit of encouragement but be careful you don’t damage the cover behind the points box – it’s relatively thin metal.
With the points box free to rotate connect a test lamp between the positive coil terminal (without fully disconnecting the connector and breaking the circuit) and earth.
It really helps if you can position the indicator lamp where it is visible both whilst you are working on the points box and from above when looking at the flywheel timing mark.
With the flywheel set at the timing mark the light should just come on. Turn the points box back and forth to find the point where the light is coming on and off. With the light just on move to the flywheel and use a large flat head screwdriver to move the flywheel back and forth slightly through the timing point ensuring the light turns on and off exactly at the mark. This should allow you to make the last adjustments to the points box to get the timing as accurate as possible.
Start tightening the points box – taking care not to disturb the position – and rotate the engine to check that the light is still coming on at the timing mark each revolution. Fully secure the points box and make a final check to ensure the timing is still correct.