So far I've been testing my car with a conventional distributor fitted. I'm only really testing it at relatively low revs so have not adjusted the advance yet. I decided that before I did set the advance, I would go ahead and fit the 123 electronic ignition that I'd bought.
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| My 123 unit - six years old! |
I can't really remember why I fitted a conventional distributor in the first place (in fact I've fitted two conventional dizzies before now!).
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| New 123 distributor and my old Ducellier 4155d |
I THINK my reasoning was to test the engine with a normal dizzy because I could follow the DS-specific set-up instructions produced by Citroen. Then, when I fitted 123, if there were problems afterwards, I'd have a good idea of the culprit. There is a bit of logic to that. But not much. You can read about the principles of DS timing HERE. And you can read about me setting the timing with a conventional DS distributor HERE. There will, by necessity, be some repetition of those posts in setting up 123.
But how do you go about setting up the timing with 123 electronic ignition? I've read comments from people on social media that gave the impression they thought they could just buy 123 and chuck it under the bonnet and it would - somehow - do-away with all the need for that complicated stuff about timing and advance.......Not so, If you are planning to fit 123, you still need to be prepared to set it up - just as you would a conventional distributor.
I've also read comments from people that mark the position of the distributor they are removing, and then fit 123 in the same position. more or less. That's not a bad start - and the engine will probably run, but without going through a more thorough set up, you probably won't get the best from 123 or the performance of your car, and could risk engine damage.
There is an official video on installing 123 electronic ignition HERE. The demonstration uses a 1966 Peugeot 404 but most of the process and principles hold good for a carburettor DS from before July 1971.
To complete the full timing process, you ideally need (access to) some key tools and gadgets:
A balloon or engine compression tester.
A timing strobe light. This will be used when setting the advance timing.
A tachometer to measure engine revs. This will also be used to set the advance.
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| Old-school tachometer with large scale |
A timing gauge already fixed to your car below the water pump.....
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| Many cars already have these fitted - though they rust and fall off |
If it's missing or broken, you can buy one to bolt on to the water pump.
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| After-market timing gauge |
or you need to temporarily rig-up something similar.
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| Home-made timing gauge |
Instructions for making a basic gauge can be found HERE.
If your hunter/ gather skills end at finding balloons, it is possible to complete the 'advance' stage timing process by sound and sense alone. Some clues are given right at the end of this post but I cannot recommend that as the way to go if you don't know what you are listening for.
So, to begin with, the engine was placed at its 'static timing position'. I did it like this
Finding The Compression Stroke
You need to start with number one cylinder in its compression stroke - not in its exhaust stroke. Here is how I found that.
I removed the spark plugs to make the engine easier to turn (you can turn it with a bit more control that way). On a bvh car releasing the 'clutch lock' lever hidden away under the dash might also help.
In lieu of a cylinder compression gauge, I rigged up a bit of soft plastic hose and a balloon in the number one cylinder. Soft hose is important so that it doesn't damage the threads in the cylinder head.
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| Using a balloon to find the compression stroke. It works with any colour of balloon. |
I used the cranking handle inserted in the gearbox to turn the engine. Alternatively - and necessary if you have a five speed gearbox - you can jack up one front wheel (securely support it safely on an axle stand) and then put the car into top gear. turning the wheel will turn the engine. If you do it this way and yours is a bvh car, don't release the clutch lock lever under the dash.
With the hose inserted by just a couple of turns to seal the cylinder, I turned the engine until the balloon just began to inflate. It just 'puffed-up' a little, but that was enough to indicate that the cylinder has began its compression stroke.
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| The balloon inflates on the compression stroke |
Finding the 'Static Timing Position'
Before I turned the engine any further, I inserted a 6mm drill in the small hole under the alternator.
It's harder to see that hole when the engine is in the car. Still can't find it? It's under the alternator and below the metal pipe that connects to the water pump. At the level of the pressure regulator.
A drill seems to be the thing of choice because you can easily find one of the right diameter, and because it's stiff - when it does it's job (see later in this post) you will know. But a drill is also a risk. After the timing position has been found, it's very important to REMOVE the drill before completing the process and starting the engine or the drill will bend and jam between the bell housing and flywheel.....
At this point - with the drill slotted in the hole - as the engine rotates, the drill end is rubbing on the rim of the rotating flywheel. But what will happen is that as the engine continues to rotate through its compression stroke, there will be a particular point at which that drill drops about 5mm and 'locks' in a notch on the rotating flywheel.
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| Timing notch on the flywheel |
That is the point we are looking for. So, once the drill has initially been inserted, it helps to have an assistant press gently down on its tip while you move on to the next step.
I continued to slowly turning the engine in its compression stroke and, at the appropriate point, the drill slipped into the timing notch in the flywheel and it would turn no further. This was the 'static timing position' for my engine.
I REMOVED THE DRILL FROM THE HOLE. I did not rotate the engine any further.
- On my car (meaning my flywheel/ my engine), the 'static timing position' so found corresponds to number one cylinder being "12 degrees before top dead centre" (sometimes abbreviated to 12 BTDC) and this is position is also the 'firing point' - the point at which ignition begins.
- On some later cars (made from about July 1971 on), the point found in this way is zero degrees before top dead centre (sometimes abbreviated to TDC).
The difference is down to where the notch on the flywheel is, and so how far the engine has to rotate before the drill drops into that flywheel notch.
The calculations for completing the timing on from July 1971 on is a little different to the calculations for the earlier cars. As my car is from 1968, I am only going to cover the process I used for my car - the process for when the 'static timing position' is the 'firing point' - 12 degrees before top dead centre.
(UPDATE: some instructions and prompts for setting the timing of post-July 1971 cars can now be found HERE.)
Before you move to the next step, put a thin white mark on the rim of the flywheel opposite the 'zero' mark of your timing gauge.
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| Thin mark on the pulley, opposite 'zero' on the gauge |
Try to make sure it's a line and not a fat blob, as a thin line will help you take a more accurate timing reading later in the process.
If you have a bvh car and released the clutch lock lever under the dash to help turn the engine, you can push it forward again - into its normal driving position.
Removing the Old Distributor
I removed the cap from my old distributor and made a mental note of which direction the rotor arm was pointing. It was pointing roughly towards the spark plug hole for number one cylinder.
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| I noted where the rotor was pointing |
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| The rotor was pointing to number 1 spark plug |
I completely removed the old distributor by loosening the pinch bolt on the securing collar. I also loosened the adjusting nut on the face of the plate so that the collar could move freely - but left the collar on the car.
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| Distributor securing collar |
It's important to remember to do up both again when refitting the 123 distributor. Firstly because you don't want your timing to 'drift' because of a loose distributor, but also because the 123 earths to the chassis through the collar and adjuster nut.
Setting Up the 123 Unit
I removed the small hex screw from the side of the 123 unit.....
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| Dial behind hex screw |
...and, with a small flat screwdriver blade, rotated the small micro-switch dial to the number/ position that was appropriate for my engine.
- If you know what your Ds is classified as (for example DX, DV, DJ) but aren't sure what dial position to use, there is a table to help you in the back of the glossy leaflet that comes with 123.
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| My car has a 'DX' engine and is classed as a 'DX' vehicle. It dates from early 1968, so the correct dial position for my engine is '6'. |
- If you can't decide what setting is right for your car because you aren't sure what DS you have, you can also look at my post HERE.
Having set the dial, I replaced the small hex screw back in the 123 unit.
Fitting the 123 Unit
On the engine, I checked the orientation of the drive socket at the very bottom of the distributor tower. Stare at it for a moment. You will see that the slot is not across the exact centre of the socket and there is a 'big half' and a 'small half'.
It's quite a subtle difference and easy to get this bit wrong. Have a long, hard stare.....
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| This photo shows the difference more clearly |
The teeth on the drive head of the123 unit are similarly aligned off-centre so that there is a 'big half' and a 'small half' to the head.
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| Drive head on the 123 unit |
You can see where I'm going with this.....That's right - when fitting, the drive head of the 123 needs to be located into the drive socket of the tower the right way round.
I removed the distributor cap from the 123 unit and, with the unit side by side with the old distributor, rotated the shaft of the 123 unit so that the rotor was broadly in the same position as on my old distributor - relative to the two clips on the sides of the bodies. There is probably a condenser on the side of the old dizzy and that roughly corresponds to the points where the two wires emerge from the 123 unit. That serves as a good 'tell' too.
I lined up the 123 unit and slotted it in the distributor tower so that the big and small halves the drive head, correctly engaged with the big and small segments in the drive socket at the base of the distributor tower. To confirm this, I gently tried to turn the rotor arm. If the unit IS correctly seated, the rotor will wiggle a fraction - because there is some free play in the drive gear - but not rotate to any significant degree. if it does rotate, then that's a sure sign that the foot isn't engaged properly.
I checked the alignment of its rotor arm: it was pointing broadly towards the spark plug of number one cylinder. Not quite the same direction as my old Ducellier distributor - but pretty close.
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| 123 pointed towards number 1 cylinder |
That was another good indication that the 123 was fitted correctly. The more important thing here, was that it WASN'T pointing towards the carburettor, alternator or radiator.......
Once I was happy that the 123 was correctly seated, I orientated the collar around the distributor so that it's slot was centred about the threaded stud of the adjuster's nut and tightened that nut down. This then gives scope for some either-way 'micro-adjustment' of the distributor if ever it's needed.
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| I centred the collar on the adjuster slot |
I tightened the pinch bolt on the clamp round the 123 just a little - so that the 123 could still be turned with a little resistance, but was not loose (could not be easily or accidentally disturbed).
I added a ring terminal to the end of the RED wire from the 123 unit and connected it to the "+" terminal of the coil. At this stage the BLACK wire from the 123 unit should not be connected.
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| Only the red wire is from the 123. The other wire is from my ignition. |
As supplied with the unit, those red and black wires are quite long and you may want to trim them to a more convenient length. But if you do that now, don't cut the wires too short!
Pre-setting the Static Timing
I turned on my ignition - just so that there was power to the coil and 123 unit. I was not actually starting the engine/ turning the engine over at this point. (For me, without a dashboard or my loom wired up, 'turning on the ignition' actually involved running a temporary flying lead from the battery positive to the coil positive).
To finish the 'pre-setting' process 123 instructions are to establish which way the rotor turns of your engine turns and then - when completing the process - to rotate the unit in the opposite direction to the normal rotation of the rotor.
For a DS, the rotor rotates clockwise, so rotating the 123 unit anti-clockwise/ counter-clockwise is correct when setting up your 123.
There is a little freeplay in the drive mechanism - as this short video shows.
VIDEO: Freeplay in the distributor mechanism.
Because of this freeplay, when the distributor is in use, there will be a little 'drag' on the rotor arm. To compensate for the freeplay (or to mimic the drag?) when setting the timing, I began by pressing the rotor anti-clockwise. It would be an exaggeration to say it rotated, I just 'took up the slack'.
Note that the silver metal 'wheel' inside the 123 has four slots around its circumference. While gently pressing on the rotor, I then VERY slowly rotated the body of the 123 unit anti-clockwise - until........a little green light *just* illuminated in one of the slots in the disc inside the 123.
This short video shows this step of the process.
VIDEO - getting the 123s green LED to light
As soon as the light illuminated, I stopped turning the 123 unit. I actually repeated this step several times, just so that I was sure I was stopping the rotation as soon as the green LED lit.
Once I was happy I'd rotated only to the point at which the LED *just* lit, I held the distributor firmly in this position, and then tightened the pinch bolt on the collar around the 123 unit in this position.
I turned off the ignition and swapped my HT leads over from the old distributor cap to the new 123 distributor cap. If you aren't sure which HT lead goes where, and have followed these instructions correctly (such that the rotor arm of your 123 unit is currently pointing approximately to number one cylinder on it's compression stroke) then these photos will help:
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| 'Stacked' cap |
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| 'Stacked' cap |
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| 'Flat' cap |
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| 'Flat' cap |
I fitted another ring connector to the BLACK wire from the 123 unit and I fixed that wire to the "-" terminal of the coil. It's the wire on the left in this photo.
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| Both wires from the 123 unit now fixed to the coil |
The process you have gone through to this point is 'pre-setting the static timing' - it's not the full timing procedure i.e. it does not include setting the engine 'advance', but should be enough to get the engine running to complete the full timing process. With your HT leads already connected, as long as you remembered to remove the drill from the hole under the alternator, you should now be in a position to re-start your car.
It's probably wise at this point to start the car and test that the engine runs. You'll also need to warm it up for the next stage.
What Is 'Advance'?
The engine 'advance' refers to the degree by which - in a high revving engine - the ignition process takes place fractionally sooner than when the engine is idling. 'Advance' is necessary because at higher revs, the pistons in the engine are moving more quickly. If ignition took place at the same time/ point as for low revs, then by the time the fuel combusted, the piston will have passed its optimum point. 'Advance' makes ignition happen sooner, so that the optimum combustion point is maintained at higher revs. On a traditional mechanical distributor, when the engine runs, advance is created by centrifugal forces acting on weights and springs, which in turn act on the rotor. On a 123 unit, all this is done electronically, making it more accurate and consistent.
Different models of Ds need different levels and rates of advance. This is because of differences in their engines. There is a table towards the end of my earlier post HERE, that lists the different amounts of advance.
Measuring 'Advance'
'Advance' refers to rotation of the crankshaft that drives the pistons. However, on a DS we measure and set advance using the camshaft and its pulley and we use the distributor. Now, the camshaft rotates at half the rate of the crankshaft, so 10 degrees of crankshaft rotation becomes only 5 degrees of camshaft rotation. or - if you prefer - 5 degrees of camshaft pulley rotation equals 10 degrees of crankshaft rotation.
At 3000rpm, my engine should have 18 degrees of advance. So that's a total of 18 degrees of crankshaft rotation BUT.....when the drill dropped into slot in the flywheel that position already gave an initial 12 degrees of (crankshaft) advance. And that's the position represented when the white mark I made on the flywheel is opposite the zero on the timing gauge - 12 degrees....
As I go through the advance-setting process, I will be looking to set a further 6 crankshaft degrees of advance. BUT, as I will be monitoring the camshaft pulley to do this, I only need to see the white mark on the pulley move from a it's 'zero' position by a further 3 degrees on the gauge. A further move of 3 degrees of the camshaft pulley will equate to the 6 degrees of crankshaft rotation/ advance that I need to set.
Phew! That's the theory. This is how I went about it.
Setting The Advance
I connected a tachometer to measure engine revs. Even if your car has a rev. counter on the dash, that may not be accurate enough for this process and so a tachometer is recommended. A large scale tachometer or a digital tachometer is the way to go.
I also connected a stroboscope to the HT lead of number one cylinder. Why number one? Well, all the work to get to this point has been based on correctly setting the position of number one cylinder.
SAFETY: you may have a lot of extra cables dangling near fans, pulleys and belts. Make sure these are tucked out of harms way before you begin. You don't want a cable being pulled into a belt or fan - and you certainly don't want your arm being dragged in too.
With the engine running, I held the engine speed at a constant 3000rpm on the tachometer and got used to the engine tone. Here's a gratuitous video of that.
VIDEO: For my engine, the advance needs to be set with the engine running at 3000 rpm
using the stroboscope I also looked at the timing mark that I had made opposite the 'zero' of my gauge when I pre-set the static timing. When the engine was idling (about 750-800 rpm) the timing mark was already at about the '3' mark on the gauge - 3 camshaft degrees/ 6 crank degrees - though it was dancing about a bit.
For this next step, the Citroen instructions are that you loosen the nut holding down the distributor collar and hold the 'tab' of the collar to set the advance - but it's near impossible to get your hand to the thing because the bracing bar for the alternator is in the way.....
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| Nut on the collar is now under the distributor |
It's far easier - and safer - to loosen the pinch bolt on the collar, leaving the collar itself secured down by the nut.
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| That pinch bolt again |
I loosened the pinch bolt nut just enough to enable me to turn the distributor - but it was still stiff to turn.
I had a glamorous assistant sit in the car, start the engine and hold it at a steady 3000rpm. At the same time I used the strobe gun to see the position of the white pulley mark against the gauge. I expected that, at 3000rpm, I would see that the white mark had now shifted further than its position when at idle. In fact, it still hovered at just over '3', so I sought to set the advance to a give me a steady 3 degrees.
- Slowly rotating the distributor body anti-clockwise increases the amount of advance.
- Rotating the distributor body and its collar clockwise reduces the amount of advance
I twisted the distributor back and forth slowly until I had got the mark on the pulley to steadily stay as close to the 3rd mark on the gauge as I could. Here is a video of that. If you click on the video, you can then put it in 'fullscreen' mode. It's quite difficult to get a camera in there, but you can just about make out the white mark on the pulley illuminated by the strobe gun.
VIDEO: Setting the advance with a strobe gun
With the mark staying steady at '3' I had the engine turned off before I re-tightened the pinch bolt on the distributor collar. With the distributor now tightened in place, I used the strobe again to re-check that, at 3000 rpm, the mark on the pulley moved to the 3rd mark of the gauge. yep. happy with that.
Recap
If you remember, I'd already set 12 degrees of crankshaft advance when I put the pin in the flywheel hole. That became the 'zero' mark on the pulley by the gauge. I'd now set another 3 degrees of pulley advance. Those 3 degrees equate to 6 crankshaft degrees - so all-in-all I'd now set a total of 18 degrees of crankshaft advance at 3000 rpm. And, according to the book, that was right for my engine.
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| Table of timing values from Manual 814 |
A Bit Of Common Sense
Now, technically, that was that - I'd fitted 123 electronic ignition and set the advance for my car as per required figures in the book. However we still need to apply a bit of common sense - eyes and ears. Modern fuels combust more slowly than leaded fuels from back in the day. This can mean that - for optimum running - we may need a little more advance than the Citroen workshop manual originally specified.
You may need to further advance the timing (advance it by more degrees) until, at higher revs, you hear 'pinking' (see below). We are not talking big changes here. Perhaps try this but then scale-back the advance until the point that you can't hear pinking. That's important.
Pinking. If you hear a metallic 'ringing' or 'pinging' sound ('pinking') this indicates that the combustion is taking place too soon (too far in advance/ too many degrees) and the burning fuel is pushing back against the piston before it has reached TDC. Pinking can cause wear to piston rings, valves and big-end bearings. Over a sustained period, it may lead to compression loss, and if left unrectified can lead to engine failure.
Next, take the car for a test drive and listen out for pinking under road conditions. If you find you can still hear pinking, you need to scale back the advance a little more and test again until there is no pinking.
Conversely, having set the advance, if your engine seems hesitant when you increase the revs, or it backfires, these are signs that the ignition is too retarded (not advanced enough): the combustion is taking place too late in the pistons stroke. Not all the fuel is being burnt up. In the longterm you would notice poor(er) fuel economy and sooty plugs. And you certainly won't see the benefit of having fitted 123. Try rotating the distributor clockwise a small amount to increase the advance but don't go crazy. and listen out for 'pinking'.
I'm surprised to find the 123 dizzy points in a slightly different direction than the conventional dizzy.
The distributor cap is now pointing directly at the oil filler tower. It's putting a bit of a stretch on the HT lead from the coil and i'm finding that one of the clips that hold the distributor cap on is hard against one of the bolts of the water pump - making it awkward to get to.
That aesthetic quibble aside, the car seems to be running fine and I can continue my testing. On'y when it's running under load will I be able to decide whether i need a little more advance.
