I've covered some of the steps of distributor fitting and ignition set-up in various rebuild and start-up posts, but as the engine is still out of my car, I've not covered the final stage of timing set up - "adjusting the static timing".
The process is included in several Operations in the Citroen Workshop Manual (Manual 814) however, in their infinite wisdom, Citroen have managed to make the practicalities of setting up the DS ignition significantly harder to understand than they need to be for the home mechanic and this is a source of ongoing confusion on social media and DS forums.
Much of the confusion is around how to decide what the appropriate target 'degrees of advance' figure is for a particular car, and how to measure and set this.
The confusion seems partly to do with:
PRINCIPLES, TERMINOLOGY AND LANGUAGE
This is a lexicon of some of the words and phrases you will find as you blunder around in the relevant sections of manual 814.
"Timing hole". This is a small hole hidden away in the bell housing beneath the alternator.
It is used to find the 'timing point' (see below).
"The timing point". This relates to putting the engine in a position where the number one piston (the one nearest the radiator fan) is at a particular point of it's compression stroke. This is achieved by placing a 6mm pin in the "timing hole" and rotating the engine/ flywheel until the point that the pin locates in a slot in the flywheel.
The key point here is that its more than just the vertical position of the piston: the car is only at the 'timing point' when the number one piston (the one nearest the radiator) is on it's compression stroke. See my post HERE for how to work that out.
"Pre-setting the static timing". Building on from finding the 'timing point' this relates to the process of a basic fitting and rotational alignment of the distributor so that the engine runs at idle/ low revs. It can be done without any special tools or timers and without the engine actually running, but it's not sufficiently accurate for the timing under driving conditions - when the engine is running at higher revs. That's where 'advance" comes into the equation.
I won't cover the principles of preparing to set up the timing, but as far as my carburettor, five bearing engined car goes, I covered pre-setting the static timing HERE.
"Timing gauge". This is a small measurement scale placed against the rim of the large camshaft pulley. The gauge can either be a permanent feature - fixed to two bolts on the lower part of the water pump - or might be a temporary fixture, suspended down from the horizontal generator/ alternator bracing bar.
The process is included in several Operations in the Citroen Workshop Manual (Manual 814) however, in their infinite wisdom, Citroen have managed to make the practicalities of setting up the DS ignition significantly harder to understand than they need to be for the home mechanic and this is a source of ongoing confusion on social media and DS forums.
 |
| Manual 814 |
The confusion seems partly to do with:
- the terminology and language used by Citroen;
- understanding the difference between crankshaft and distributor degrees;
- trying to interpret all of this through a PDF copy of the manual, and - PDF or not;
- typos in the original Citroen workshop manual!
- a car from a particular year doesn't have it's original engine type and/ or capacity (cc), or perhaps has a different carburettor, or a different distributor.
- someone wants to replace a mechanical distributor with '123 electronic ignition'
PRINCIPLES, TERMINOLOGY AND LANGUAGE
This is a lexicon of some of the words and phrases you will find as you blunder around in the relevant sections of manual 814.
"Timing hole". This is a small hole hidden away in the bell housing beneath the alternator.
 |
| The hole for the timing pin is under the alternator mounting point |
"The timing point". This relates to putting the engine in a position where the number one piston (the one nearest the radiator fan) is at a particular point of it's compression stroke. This is achieved by placing a 6mm pin in the "timing hole" and rotating the engine/ flywheel until the point that the pin locates in a slot in the flywheel.
 |
Timing Notch in Flywheel
|
 |
| 6mm twist drill in timing hole under the alternator |
- For DS carburettor cars unto July 1971, the pin in the timing hole and flywheel slot stopped the crankshaft at 12 degrees before the piston reaches top dead centre (12 degrees BTDC)
- For DS cars after July 1971 the flywheel changed such that the pin in the slot stopped the crankshaft at zero degrees before top dead centre (TDC) - i.e. at TDC and so the point after which the piston begins its downward motion.
(Just as an aside here, on a fuel injected car, the timing notch gave 81/2 degrees (8 degrees, 30 minutes) unto July 1971. After that it gave TDC).
 |
| Setting the pre-static timing with a test lamp. |
"Timing gauge". This is a small measurement scale placed against the rim of the large camshaft pulley. The gauge can either be a permanent feature - fixed to two bolts on the lower part of the water pump - or might be a temporary fixture, suspended down from the horizontal generator/ alternator bracing bar.
 |
| A workshop timing gauge fitted against the pulley (note scale marks are every 2 degrees.....) |
 |
| After-market iming gauge as fitted to water pump (note scale marks are every 1 degree) |
"Static advance position" and "the static advance point". These are very closely related terms. The 'static advance position' seems to be used to describe the rotational position of the crankshaft found through the process of "pre-setting the static timing" above. "Static advance point" is also used to describe this and is also the basis of the associated fixed reference mark then made on the flywheel opposite the 'zero' mark on the timing gauge.
 |
| The 'timing point' marked opposite the 'zero' of the timing gauge |
"Advance". In all cases, firing needs to begin before the piston is at the top of it's stroke, to ensure that fuel/ air combustion takes place at the optimum point in relation to the piston position. Advance is necessary because while the time taken for the piston to go through it's cycle shortens at higher engine speeds, the time it takes for fuel to combust remains more or less constant. The firing point - the point at which ignition starts - therefore needs to start sooner at higher speeds, to ensure that combustion still takes place at the optimum point. How much sooner is called the 'advance'. Advance is not measured in units of time, but in degrees of rotation of the crankshaft relative to it's position when the piston is at the very top of it's stroke - top dead centre (TDC). It's all very straightforward.
 |
| What we don't need to know |
Here's a little video I made that shows how the rotor arm (and so firing point) is advanced by the movement of weights - normally under rotation - not my fingers. The faster the rotation, the more the weights would move. The advance curve (graph) is a plot of this movement.
VIDEO: the 'advance' action inside a distributor
"Adjusting the static timing". Building on from 'pre-setting the static timing", this relates to the process of fine tuning the timing setting (the 'advance') to optimise performance when the engine is running at speed. It is carried out with the engine running at specified revs, and involves the use of a stroboscope, tachometer (rev counter) and timing gauge.
 |
| Using a stroboscope to measure and adjust the static timing |
THE DIFFERENCE BETWEEN CRANKSHAFT AND DISTRIBUTOR DEGREES
In a four stroke engine, the crankshaft rotates twice, as each piston goes through four 'strokes' (two up and two down) to complete one combustion cycle. In a four stroke ignition cycle, the ignition spark only needs to be created once in that cycle, and so the distributor only needs to be rotated once for every two rotations of the crankshaft. To facilitate this (the necessary gearing), the camshaft sprocket is twice the size of the crankshaft sprocket to create a 2:1 rotation ratio.
 |
| Crankshaft pinion at the bottom. Camshaft pinion at the top |
- In order to to influence the firing point of the engine in terms of crankshaft rotation
- We physically rotate the distributor to cause firing to happen sooner or later.
- Because they rotate at the same rate, for convenience we monitor and measure the impact of that adjustment of the distributor against a reference mark on the camshaft pulley.
- As measured on the camshaft pulley, a half rotation of the distributor (180 distributor degrees) equates to a full rotation of the crankshaft (360 crankshaft degrees)
- As measured on the camshaft pulley, a quarter rotation of the distributor (90 distributor degrees) equates to a half rotation of the crankshaft (180 crankshaft degrees)
- As measured on the camshaft pulley, 4 degrees of rotation of the distributor equates to 8 degrees of rotation of the crankshaft.
NAVIGATING VOLUME 1 OF MANUAL 814
I'm going to assume here that most people wanting to set their ignition up will be accessing Manual 814 as an electronic PDF document. ((For the most up-to-date and complete version. Source it from HERE.))
The basic timing process has three main steps:
- Finding the timing point
- Pre-setting the static timing
- Adjusting the static timing
Confirm the age of your vehicle and so it's intended specification and fittings
In France the factory production year ran from September to July with a month's shutdown in August. A "1972 DSuper" is generally taken to refer to a DSuper made in, and for, the "1972 model year" - so anytime between September 1971 and September 1972. So a car built in 1971, can be a "1972" car. Or it might be sold to you as a '1971' car........You might also find a 1985cc 'DSuper' wrongly described/ sold as a 2175cc "DSuper5". This is often a source of confusion with cars bought second hand and when you need to buy particular parts or carry out particular jobs - like setting the timing.....
For these, and other reasons, it's always handy to know what your car was actually built as - and when. For the majority of cars, you can established what model year your car is by looking up it's chassis number on one of the lists available on line. Like the ones in the links by clicking HERE.
If your car is European built, you should be able to find it's chassis number within the ranges given in one or other of these lists.
Make a note of the type (e.g DSpecial/ DSuper5) and model year of your car based on it's chassis number.
Confirm the factory vehicle type 'General Symbols' for your car
Okay, so say, from the chassis number, you've confirmed that your car is a 1972 DSpecial as you knew all along. Well, your car may be a DSpecial and have a tag on the engine that says its a 'DY3', and the coloured tag up by the wiper motor may say its a 'Serie FD' but guess what? As far as the factory bods at Citroen are concerned, it's a 'DV'! A D Super also has a tag on the engine that says its a 'DY3', and the coloured tag up by the wiper motor also says its a 'Serie FD' but guess what? That's not a 'DV' it's a 'DT'! A key difference here is the performance characteristics of the different models. Not engine capacity (both are 1985cc) but more to do with the carburettor and brake horse power (bhp) I suspect.
There are two A3-sized landscape tables of 'general characteristics' in the very early pages of volume 1 of manual 814 - immediately after the 'contents' section. You can find them in the PDF version of the manual as well as in the paper version.
 |
| DS vehicles: general characteristics |
 |
| Example: a 'DSpecial' is classified as a 'DV' vehicle |
Make a note those two letters for your particular car, based on it's model year of manufacture - as established from the chassis number.
Also note the engine type your car should have/ had when it was manufactured (e.g. DY3, DV2, DX2 etc)
Operation D.210-00 in Volume 1 of Manual 814
This dives right down into it, and is mostly a series of graphs for the different 'advance curves' for the distributors used with different models. I'm not sure why the lines on the graphs are so thick. They were either drawn with a very fat crayon or suggest there is a LOT of tolerance in the settings?
As well as the graph, each 'curve' section lists the type of distributor relevant to that curve and as fitted to the vehicles covered. It might have been a Ducellier brand distributor, or it might have been SEV-Marchal. Both would have been configured to do the same job. Regardless of brand, two distributors having the same advance curve characteristics will share a common identifying 'mark'. Here's an example of a Ducellier 4254C. It's behaviour is given by curve C12.
 |
| As well as the branded model number (4254C)...... |
 |
| .....the distributor has common identifying code (DV 010) |
 |
| Example of advance curve information - in this case 'C12' |
 |
| Similar information. Different presentation |
Notice that both tables also give the model number of the distributor (either Ducellier or SEV-Marchal brand) that the advance curve is a representation of.
Using the 'general symbol' and vehicle manufacturing year for your car, make a note of the appropriate curve 'C' number (e.g. C8 means advance curve 8).
Make a note of the brand and model number of the distributor that your car was originally supplied with.
Why are there different distributors and advance curves? To be honest, I don't fully know. However the way a distributor is configured (dwell angle, how much it advances ignition and when) will reflect how the engine is designed and intended to perform - so distributor behaviour will reflect engine cubic capacity, compression, fuel octane, the carburettor, gearing, planned fuel economy and emission control for example. That's why one size does not fit all.
Operation D.210-0 in Volume 1 of Manual 814
This follows on from the Operation above and covers cars that have a carburettor. There is a similar, but separate Operation D.IE.210-0 for fuel injected cars.
Remember I said there were three main steps to the process?
Page one covers finding the timing point and the process of "pre-setting the static timing" for vehicles built before July 1971.
Page two covers finding the timing point and the process of "pre-setting the static timing" for vehicles built after July 1971.
What's the difference? Well - it's all to do with that notch in the flywheel and whether, for a carburettor car, you are starting the process from 12 degrees before top dead centre, or starting from top dead centre.....Although written-up differently, the instructions are essentially the same.
Page three covers the theory and principles behind "adjusting the static timing" and makes reference to two un-numbered fold-out pages. In a physical copy of the manual, the cross-referencing of the text to these fold out pages kind of makes sense, but in PDF form you stumble, out of sequence, across two scary graphs with the axes labelled in French, before you hit the page that refers-back to them.
 |
| The fold out pages lose some sense in a pdf version of the manual |
Page 4 of Operation D.210-0 is a crucial bit of information: a look up table that gives the measurements and figures you are meant to use when embarking on checking and setting the ignition ('adjusting the the static timing') for your particular car. It's also one of the major reasons for confusion.
Part of the confusion associated with the table comes from the fact that the timing gauge has a scale that goes to over 20 degrees: the temptation is to assume that the big numbers in column B must be the numbers you are trying to obtain when setting the timing. You are.....but you aren't........
Given that you need to halve the crankshaft degrees when measuring on the camshaft, the most movement you will be trying to see when measuring against the gauge is half of the figure shown in column B - at most, 14 degrees for the relevant cars covered by Curve C11.
Also note that column B shows the total advance - in other words, for vehicles where the timing pin gives 12 degrees before top dead centre, the value listed includes those initial 12 degrees.
By contrast, column C shows distributor degrees. Furthermore, the values listed relate to the additional degrees of advance....... above and beyond the 12 crankshaft degrees advance already obtained on cars where the timing notch gives such.
Confused? It's not black magic. There is a logical relationship between columns B and C. It's this:
C = (B minus 12) divided by 2
In other words: take the total (desired) advance degrees, then subtract 12 degrees (because the timing pin sets the timing at that point to start with). Of the remaining advance, then halve the figure (because you will measure it on the camshaft, which is a proxy for the distributor - which rotates at half the rate of the crankshaft). Got it?
(The formula also works for fuel injected cars built before July 1971: 6 3/4 distributor degrees equals (22 crankshaft degrees - 8 1/2) divided by 2).
Now the confusion with the table comes from the fact that, taken in isolation, the inference is that the maths above and the figure in column C is applicable, and useful information for, all vehicles covered by, say, Curve C11. HOWEVER, some rows (curves) cover cars produced before and cars produced after July 71 - so in some cases after the position of the timing notch changed. The affected curves are C9, C11 and C12.
The impact of this (and even though they carry the same factory 'general symbol'), is that for some vehicles covered by these rows you do use the the Column C figure published by Citroen, but for others you do not....... The use of a 'column C' figure calculated above is only relevant to pre-July 1971 vehicles (engines) where the timing pin sets the crank at 12 degrees BTDC.
To illustrate this, notice that the bottom of the two rows for curve C12 has no figure in column C. That is because all vehicles covered by this row were manufactured after the timing notch in the flywheel changed to give 'top dead centre'. So for this row (and while you do still need to set advance relative to the 'static setting point' for these cars) the calculation process would be different (you do not subtract 12) so there is no directly comparable figure to include in 'column C'.
Part of the confusion associated with the table comes from the fact that the timing gauge has a scale that goes to over 20 degrees: the temptation is to assume that the big numbers in column B must be the numbers you are trying to obtain when setting the timing. You are.....but you aren't........
Given that you need to halve the crankshaft degrees when measuring on the camshaft, the most movement you will be trying to see when measuring against the gauge is half of the figure shown in column B - at most, 14 degrees for the relevant cars covered by Curve C11.
 |
| ORIGINAL 'page 4' table of Ignition Values. Here Be Monsters......... |
By contrast, column C shows distributor degrees. Furthermore, the values listed relate to the additional degrees of advance....... above and beyond the 12 crankshaft degrees advance already obtained on cars where the timing notch gives such.
Confused? It's not black magic. There is a logical relationship between columns B and C. It's this:
C = (B minus 12) divided by 2
In other words: take the total (desired) advance degrees, then subtract 12 degrees (because the timing pin sets the timing at that point to start with). Of the remaining advance, then halve the figure (because you will measure it on the camshaft, which is a proxy for the distributor - which rotates at half the rate of the crankshaft). Got it?
(The formula also works for fuel injected cars built before July 1971: 6 3/4 distributor degrees equals (22 crankshaft degrees - 8 1/2) divided by 2).
Now the confusion with the table comes from the fact that, taken in isolation, the inference is that the maths above and the figure in column C is applicable, and useful information for, all vehicles covered by, say, Curve C11. HOWEVER, some rows (curves) cover cars produced before and cars produced after July 71 - so in some cases after the position of the timing notch changed. The affected curves are C9, C11 and C12.
The impact of this (and even though they carry the same factory 'general symbol'), is that for some vehicles covered by these rows you do use the the Column C figure published by Citroen, but for others you do not....... The use of a 'column C' figure calculated above is only relevant to pre-July 1971 vehicles (engines) where the timing pin sets the crank at 12 degrees BTDC.
To illustrate this, notice that the bottom of the two rows for curve C12 has no figure in column C. That is because all vehicles covered by this row were manufactured after the timing notch in the flywheel changed to give 'top dead centre'. So for this row (and while you do still need to set advance relative to the 'static setting point' for these cars) the calculation process would be different (you do not subtract 12) so there is no directly comparable figure to include in 'column C'.
So anyway, building on what Citroen started with the very bottom C12 row of the table, I thought it would be better if the table was totally split out according to pre/ post timing notch change. So I re-drew it. It looks like this:
I've aded rows, an extra part to 'column C' and I've done the maths for you. I've then greyed-out non-essential boxes. This is only good for cars with a carburettor, but laid out like this the table is far easier to understand: depending on the 'general symbol' type and year of manufacture of your car, you identify the relevant row, and then look up the figure listed in 'column C'. When the time comes to it, you are looking to read these 'distributor degree' figures off the timing gauge by the camshaft pulley
For vehicles produced before July 1971 (in other words for those vehicles where the timing pin gives 12 degrees before top dead centre):
Ignore columns B. With the mark made on the pulley opposite 'zero' on the gauge, at the engine revs given in Column A, you will want to see the mark displaced by the number of degrees given in the first half of Column C. Simple as that
For vehicles produced since July 1971 (in other words for those vehicles where the timing pin gives top dead centre):
Do the same. Ignore column B. With the mark made on the pulley opposite 'zero' on the gauge, at the engine revs given in Column A, you will want to see the mark displaced by the number of degrees given in the other half of Column C.
It's because of the choice of two different figures that you could use, that its absolutely crucial to know your engine, and whether your timing pin notch gives 12 degrees before top dead centre, or top dead centre itself.
Glad we got that cleared up. If that was about unhelpful layout, lets move on to typos in the manual.
 |
| UPDATED table: expanded and improved |
For vehicles produced before July 1971 (in other words for those vehicles where the timing pin gives 12 degrees before top dead centre):
Ignore columns B. With the mark made on the pulley opposite 'zero' on the gauge, at the engine revs given in Column A, you will want to see the mark displaced by the number of degrees given in the first half of Column C. Simple as that
For vehicles produced since July 1971 (in other words for those vehicles where the timing pin gives top dead centre):
Do the same. Ignore column B. With the mark made on the pulley opposite 'zero' on the gauge, at the engine revs given in Column A, you will want to see the mark displaced by the number of degrees given in the other half of Column C.
It's because of the choice of two different figures that you could use, that its absolutely crucial to know your engine, and whether your timing pin notch gives 12 degrees before top dead centre, or top dead centre itself.
Glad we got that cleared up. If that was about unhelpful layout, lets move on to typos in the manual.
TYPOS IN MANUAL 814
Pages 5, 6 and 7. In an effort to be helpful, pages 5 to 7 (parts 'IV' to 'VI') of Operation D.210-0 give several practical examples of how to adjust the timing using a stroboscope and with/ without a phaser. Unfortunately, because of typos in the Manual, these only add to the confusion and seem at odds with the preceding pages and my write-up above.
In the English language version of the manual all three of these sections are mislabelled as being applicable to vehicles manufactured from July 1971:
A careful reading of the text shows this cannot be right - and this is confirmed by a cross-check to the original French language manual 583. This shows that parts IV and V actually refer to vehicles manufactured before July 1971, and only part 'VI' covers vehicles after July 1971.
The basic procedure for setting the timing on five bearing cars produced between 1966 and July 1971 is given by sections 'IV' and 'V' of Operation D.210-0 in volume one of manual 814.
The basic procedure for setting the timing on five bearing cars produced since July 1971 is given by section 'VI' of Operation D.210-0 in volume one of manual 814.
When read in this way, and alongside the expanded table above, the instructions make sense and are consistent with the earlier parts of the manual. When it comes to steps 4 and 5 in Section VI (vehicles since July 1971), I've already done the maths for you in my expanded 'page 4' table: just use the figure in the second half of column C.
There is also another point on these pages that causes confusion: the example given in section 'IV' states that each mark on the timing gauge corresponds to two distributor degrees.
EXAMPLES
Now lets put it all together an look at some common examples. For these, I'm going to assume that, after your background research, you have confirmed that your car is stock standard and as it drove out of the factory. I'm also going to duck a discussion about correct coils, contact breaker gaps and spark plugs:
Example 1 - 1971 DSpecial
A DSpecial of the 1971 model year would have a 1985cc DV2 engine and is classified as a 'DV' vehicle by the factory. The distributor should be marked 'DV-010A' and it's behaviour is given by Curve C12. From the table, timing should be carried out at 2000rpm and the total advance should be 24 crankshaft degrees. Since the pin in the timing notch of the flywheel already gives 12 crankshaft degrees before TDC, then to achieve the required 24 degrees at the specified revs, the timing needs to be adjusted to achieve an additional 12 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further six degrees. The figure given by 'column C' in my revised table.
Example 2 - 1972 DSpecial
A DSpecial of the 1972 model year would have a 1985cc DV3 engine and is classified as a 'DV' vehicle by the factory. The distributor should be marked 'DV-010A' and it's behaviour is given by Curve C12. From the table, timing should be carried out at 2000rpm and the total advance should be 24 crankshaft degrees. However, and unlike the car in example 1 above,
the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 24 degrees at the specified revs, the timing needs to be adjusted to achieve the full 24 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further twelve degrees. The figure given by 'column C' in my revised table.
Example 3 - 1973 DSpecial
A DSpecial of the 1973 model year would have a 1985cc DY3 engine and is classified as a 'DV' vehicle by the factory. The distributor should be marked 'DY-010A' and it's behaviour is given by Curve C11. From the table, timing should be carried out at 2000rpm and the total advance should be 28 crankshaft degrees. For a vehicle of this year, the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 28 degrees at the specified revs, the timing needs to be adjusted to achieve the full 28 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further fourteen degrees. The figure given by 'column C' in my revised table.
Example 4 - 1972 DSuper
A DSuper of the 1972 model year would have a 1985cc DY2 engine and is classified as a 'DT' vehicle by the factory. The distributor also should be marked 'DY-010A' and it's behaviour is also given by Curve C11. From the table, timing should be carried out at 2000rpm and the total advance should be 28 crankshaft degrees. For a vehicle of this year, the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 28 degrees at the specified revs, the timing needs to be adjusted to achieve the full 28 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further fourteen degrees.The figure given by 'column C' in my revised table.
Example 5 - My 1968 year DS21
A DS21 of the 1968 model year would have a 2175cc DX engine and is classified as a 'DX' vehicle by the factory. The distributor should be marked 'DX-05b' and it's behaviour is given by Curve C6. From the table, timing should be carried out at 3000rpm and the total advance should be 18 crankshaft degrees. Since the pin in the timing notch of the flywheel already gives 12 crankshaft degrees before TDC, then to achieve the required 18 degrees at the specified revs, the timing needs to be adjusted to achieve an additional 6 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, we would be looking to see a mark initially made against 'zero' on the gauge move by a further three camshaft degrees. In other words the figure given by 'column C' in the table.
Example 6 - 1971 DS21
A DS21 of the 1971 model year would have a 2175cc DX2 engine and is classified as a 'DX' vehicle by the factory. The distributor should be marked 'DX-05i' and it's behaviour is given by Curve C9. From the table, timing should be carried out at 2000rpm and the total advance should be 20 crankshaft degrees. Since the pin in the timing notch of the flywheel already gives 12 crankshaft degrees before TDC, then to achieve the required 20 degrees at the specified revs, the timing needs to be adjusted to achieve an additional 8 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, we would be looking to see a mark initially made against 'zero' on the gauge move by a further four camshaft degrees. In other words the figure given by 'column C' in the table.
Example 7 - 1973 DSuper 5
A DSuper 5 of the 1973 year would have a 2175cc DX2 engine and is classified by the factory as a 'DP' vehicle. The distributor should be marked 'DX-05i' and it's behaviour is given by Curve C9. From the table, timing should be carried out at 2000rpm and the total advance should be 20 crankshaft degrees. For a vehicle of this year, the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 20 degrees at the specified revs, the timing needs to be adjusted to achieve the full 20 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further ten degrees. The figure given by 'column C' in my revised table.
'123' ELECTRONIC IGNITION
I wrote earlier in this post that I would touch on fitting '123' electronic ignition. I have heard people say (write) that they intend to replace their mechanical distributor with '123' because they "........can just chuck it in."
The thing to know about '123' is that, while it replaces the mechanical contact breakers and the advance is produced electronically (rather than by weights and springs) it's still driven by the camshaft and still needs to be 'told' when to produce the spark and for which cylinder.
In short, the set up process for 123 is the same as for a mechanical distributor. It has, however a got a neat little trick and a neat big trick:
Little trick: when you are pre-setting the static timing: t's got a little green LED hidden away inside to help with this - so none of that mucking around with crocodile clips and a test lamp as you twist the distributor looking for the 'sweet spot'.
Big and best trick: as the advance is controlled electronically, it can be set up to mimic the advance characteristic of many of the different distributors fitted to different D models. This is done with a little selector dial hidden away behind a hex nut.
'123' obviously comes with instructions that tell you what number on the dial corresponds to what advance curve. If you car engine and it's mechanical distributor are given by curve C11 then, if you fit '123' electronic ignition, simply set the selector to the number that corresponds to curve C11 - then go through the normal timing set up process.......
'123' receives very good reports and I succumbed to one one myself. Although it has the 'big trick' described above, there are still several different versions available to cover the full range of DS models - so do a bit of research first and buy the '123' unit according to your circumstances and needs. Which probably brings me to 'mix and match' below.
MIX AND MATCH
I also wrote earlier that I would touch on some thoughts about what to do if you need to set up your timing, but (following your background research)........discover that your car isn't factory spec. Maybe it's got the wrong (non-standard) engine for it's model or age. Maybe it's got the wrong distributor. Maybe it's got the wrong carburettor. Maybe they're all wrong! How do you interpret the timing instructions? That's where some of the fact-finding work in red text above comes into play.......
Well the most I can offer here is an opinion. So here goes:
Firstly, I don't think it's going to cause any major mechanical problems to have the wrong distributor - as long as it is set up right, though the car may be down on performance. I say this for two reasons: firstly, I drove a DS for several years that had the wrong distributor fitted. It took me all over France. Secondly, if you look at the websites of the part sellers you can 'upgrade' a 1985cc engine by using the cylinders and pistons for a 2175cc engine. There is no mention of needing to swap the carburettor, or mention of needing to re-set the timing according to any special formula. The car will presumably still run......
Here are some other typical scenarios with suggestions of how you might approach them from a 'setting-the-timing' perspective. I think my approach seems to be "distributor trumps engine, engine trumps model and year":
If you find that your car has the right engine, but wrong mechanical distributor. There is probably little value in setting it up as though it were the right distributor for your car (engine): the distributor will probably not behave as the engine requires it to. The distributor characteristics (weights and springs) are the constraint. I would recommend setting the distributor up using the timing curve for the distributor type/ model, and how it will actually behave. I don't think the car will run at it's very best - but it will run. If you're not happy, perhaps you could then try setting it up the other way - based on the engine/ your car. If you can afford it, a better solution would be to fit '123' - as you can then set that up according to what your car/ engine should have.
If you car has the the wrong engine and mechanical distributor for it's model and year. Maybe the car is a DSpecial, but someone has dropped in the engine and ancillaries from a DSuper5. Assuming the distributor is, at least, the right one for the engine, then it makes sense to ignore what your model is meant to have, and to set the distributor up according to the timing curve for it's type, and so the engine it is paired with.
If the engine and distributor are mismatched, then it's rather like the previous example above: my advice would be to set the distributor up according to the timing curve for the distributor type/ model. Again, as above, there is nothing to stop you setting it up according to the engine type if you're not happy with performance. And again, as a move, fitting '123' according to the engine type would at least enable you to set it up to get the best out of your engine.
If your car has the right mechanical distributor, but the wrong engine. It can happen! As above, my advice would be to set the timing according to the curve for the distributor you have. See how you get on. If you're not happy with performance, you could try the alternative of setting it according to the engine type.
Like I say, these are just my opinions. No guarantees. You are going to need to experiment and use some common sense.
FINAL THOUGHT
I've got a final word on setting the timing on a DS and using the information in the factory manual.....and it's also about the need for a little common sense.
All the figures and calculations in the manual are based on engines running on high octane leaded fuel in the 1960s and 1970s. Modern unleaded fuel combusts at a slower rate than leaded fuel so, when using unleaded fuel, to ensure that combustion still takes place at the optimum point, ignition needs to begin sooner: you may need to increase the advance above and beyond the figures given in the manual.
There is probably a way to measure all this scientifically with a gas tester etc, but may not have any special kit available. As such, it becomes a matter of using your eyes and ears when adjusting the static timing and listening to what your engine is telling you.
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.
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. Rotating the distributor anticlockwise a little will increase the advance.
Perhaps try this and then scale-back the advance until you can't hear pinking. That's important.
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.
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.
Well that's about it. I hope the above gives some context to car ignition and helps to demystify Manual 814.
In the English language version of the manual all three of these sections are mislabelled as being applicable to vehicles manufactured from July 1971:
 |
| Part 'IV' in Manual 814: vehicles from July 1971 |
 |
| Part 'IV' in Manual 583: vehicles up to July 1971......... |
The basic procedure for setting the timing on five bearing cars produced between 1966 and July 1971 is given by sections 'IV' and 'V' of Operation D.210-0 in volume one of manual 814.
The basic procedure for setting the timing on five bearing cars produced since July 1971 is given by section 'VI' of Operation D.210-0 in volume one of manual 814.
There is also another point on these pages that causes confusion: the example given in section 'IV' states that each mark on the timing gauge corresponds to two distributor degrees.
 |
| After-market gauges actually have one graduation fo each distributor degree |
This may have been the case on the workshop or original fitment gauges, but the current after-market gauges have a mark for each distributor degree. So some common sense is needed when interpreting the scale you use on your own car.
EXAMPLES
Now lets put it all together an look at some common examples. For these, I'm going to assume that, after your background research, you have confirmed that your car is stock standard and as it drove out of the factory. I'm also going to duck a discussion about correct coils, contact breaker gaps and spark plugs:
Example 1 - 1971 DSpecial
A DSpecial of the 1971 model year would have a 1985cc DV2 engine and is classified as a 'DV' vehicle by the factory. The distributor should be marked 'DV-010A' and it's behaviour is given by Curve C12. From the table, timing should be carried out at 2000rpm and the total advance should be 24 crankshaft degrees. Since the pin in the timing notch of the flywheel already gives 12 crankshaft degrees before TDC, then to achieve the required 24 degrees at the specified revs, the timing needs to be adjusted to achieve an additional 12 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further six degrees. The figure given by 'column C' in my revised table.
Example 2 - 1972 DSpecial
A DSpecial of the 1972 model year would have a 1985cc DV3 engine and is classified as a 'DV' vehicle by the factory. The distributor should be marked 'DV-010A' and it's behaviour is given by Curve C12. From the table, timing should be carried out at 2000rpm and the total advance should be 24 crankshaft degrees. However, and unlike the car in example 1 above,
the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 24 degrees at the specified revs, the timing needs to be adjusted to achieve the full 24 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further twelve degrees. The figure given by 'column C' in my revised table.
Example 3 - 1973 DSpecial
A DSpecial of the 1973 model year would have a 1985cc DY3 engine and is classified as a 'DV' vehicle by the factory. The distributor should be marked 'DY-010A' and it's behaviour is given by Curve C11. From the table, timing should be carried out at 2000rpm and the total advance should be 28 crankshaft degrees. For a vehicle of this year, the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 28 degrees at the specified revs, the timing needs to be adjusted to achieve the full 28 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further fourteen degrees. The figure given by 'column C' in my revised table.
Example 4 - 1972 DSuper
A DSuper of the 1972 model year would have a 1985cc DY2 engine and is classified as a 'DT' vehicle by the factory. The distributor also should be marked 'DY-010A' and it's behaviour is also given by Curve C11. From the table, timing should be carried out at 2000rpm and the total advance should be 28 crankshaft degrees. For a vehicle of this year, the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 28 degrees at the specified revs, the timing needs to be adjusted to achieve the full 28 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further fourteen degrees.The figure given by 'column C' in my revised table.
Example 5 - My 1968 year DS21
A DS21 of the 1968 model year would have a 2175cc DX engine and is classified as a 'DX' vehicle by the factory. The distributor should be marked 'DX-05b' and it's behaviour is given by Curve C6. From the table, timing should be carried out at 3000rpm and the total advance should be 18 crankshaft degrees. Since the pin in the timing notch of the flywheel already gives 12 crankshaft degrees before TDC, then to achieve the required 18 degrees at the specified revs, the timing needs to be adjusted to achieve an additional 6 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, we would be looking to see a mark initially made against 'zero' on the gauge move by a further three camshaft degrees. In other words the figure given by 'column C' in the table.
Example 6 - 1971 DS21
A DS21 of the 1971 model year would have a 2175cc DX2 engine and is classified as a 'DX' vehicle by the factory. The distributor should be marked 'DX-05i' and it's behaviour is given by Curve C9. From the table, timing should be carried out at 2000rpm and the total advance should be 20 crankshaft degrees. Since the pin in the timing notch of the flywheel already gives 12 crankshaft degrees before TDC, then to achieve the required 20 degrees at the specified revs, the timing needs to be adjusted to achieve an additional 8 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, we would be looking to see a mark initially made against 'zero' on the gauge move by a further four camshaft degrees. In other words the figure given by 'column C' in the table.
Example 7 - 1973 DSuper 5
A DSuper 5 of the 1973 year would have a 2175cc DX2 engine and is classified by the factory as a 'DP' vehicle. The distributor should be marked 'DX-05i' and it's behaviour is given by Curve C9. From the table, timing should be carried out at 2000rpm and the total advance should be 20 crankshaft degrees. For a vehicle of this year, the pin in the timing notch of the flywheel gives top dead centre - zero degrees before TDC. To achieve the required 20 degrees at the specified revs, the timing needs to be adjusted to achieve the full 20 crankshaft degrees. As this would be measuring on a gauge against the camshaft pulley, you would be looking to see a mark initially made against 'zero' on the gauge move by a further ten degrees. The figure given by 'column C' in my revised table.
'123' ELECTRONIC IGNITION
I wrote earlier in this post that I would touch on fitting '123' electronic ignition. I have heard people say (write) that they intend to replace their mechanical distributor with '123' because they "........can just chuck it in."
 |
| '123' fitted (photo from 'www.classicautoelec.com') |
 |
| 123 ignition is still driven by the camshaft...... |
 |
| .....and still distributes the spark via a rotor |
Little trick: when you are pre-setting the static timing: t's got a little green LED hidden away inside to help with this - so none of that mucking around with crocodile clips and a test lamp as you twist the distributor looking for the 'sweet spot'.
 |
| Little green timing LED visible through the slot |
 |
| 123 can replicate different DS advance curves. |
'123' receives very good reports and I succumbed to one one myself. Although it has the 'big trick' described above, there are still several different versions available to cover the full range of DS models - so do a bit of research first and buy the '123' unit according to your circumstances and needs. Which probably brings me to 'mix and match' below.
MIX AND MATCH
I also wrote earlier that I would touch on some thoughts about what to do if you need to set up your timing, but (following your background research)........discover that your car isn't factory spec. Maybe it's got the wrong (non-standard) engine for it's model or age. Maybe it's got the wrong distributor. Maybe it's got the wrong carburettor. Maybe they're all wrong! How do you interpret the timing instructions? That's where some of the fact-finding work in red text above comes into play.......
Well the most I can offer here is an opinion. So here goes:
Firstly, I don't think it's going to cause any major mechanical problems to have the wrong distributor - as long as it is set up right, though the car may be down on performance. I say this for two reasons: firstly, I drove a DS for several years that had the wrong distributor fitted. It took me all over France. Secondly, if you look at the websites of the part sellers you can 'upgrade' a 1985cc engine by using the cylinders and pistons for a 2175cc engine. There is no mention of needing to swap the carburettor, or mention of needing to re-set the timing according to any special formula. The car will presumably still run......
Here are some other typical scenarios with suggestions of how you might approach them from a 'setting-the-timing' perspective. I think my approach seems to be "distributor trumps engine, engine trumps model and year":
If you find that your car has the right engine, but wrong mechanical distributor. There is probably little value in setting it up as though it were the right distributor for your car (engine): the distributor will probably not behave as the engine requires it to. The distributor characteristics (weights and springs) are the constraint. I would recommend setting the distributor up using the timing curve for the distributor type/ model, and how it will actually behave. I don't think the car will run at it's very best - but it will run. If you're not happy, perhaps you could then try setting it up the other way - based on the engine/ your car. If you can afford it, a better solution would be to fit '123' - as you can then set that up according to what your car/ engine should have.
If you car has the the wrong engine and mechanical distributor for it's model and year. Maybe the car is a DSpecial, but someone has dropped in the engine and ancillaries from a DSuper5. Assuming the distributor is, at least, the right one for the engine, then it makes sense to ignore what your model is meant to have, and to set the distributor up according to the timing curve for it's type, and so the engine it is paired with.
If the engine and distributor are mismatched, then it's rather like the previous example above: my advice would be to set the distributor up according to the timing curve for the distributor type/ model. Again, as above, there is nothing to stop you setting it up according to the engine type if you're not happy with performance. And again, as a move, fitting '123' according to the engine type would at least enable you to set it up to get the best out of your engine.
If your car has the right mechanical distributor, but the wrong engine. It can happen! As above, my advice would be to set the timing according to the curve for the distributor you have. See how you get on. If you're not happy with performance, you could try the alternative of setting it according to the engine type.
Like I say, these are just my opinions. No guarantees. You are going to need to experiment and use some common sense.
FINAL THOUGHT
I've got a final word on setting the timing on a DS and using the information in the factory manual.....and it's also about the need for a little common sense.
All the figures and calculations in the manual are based on engines running on high octane leaded fuel in the 1960s and 1970s. Modern unleaded fuel combusts at a slower rate than leaded fuel so, when using unleaded fuel, to ensure that combustion still takes place at the optimum point, ignition needs to begin sooner: you may need to increase the advance above and beyond the figures given in the manual.
There is probably a way to measure all this scientifically with a gas tester etc, but may not have any special kit available. As such, it becomes a matter of using your eyes and ears when adjusting the static timing and listening to what your engine is telling you.
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.
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. Rotating the distributor anticlockwise a little will increase the advance.
Perhaps try this and then scale-back the advance until you can't hear pinking. That's important.
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.
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.
Well that's about it. I hope the above gives some context to car ignition and helps to demystify Manual 814.
Find a nearby hill, loosen the distributor so it can be rotated by hand. Drive up the hill in a high gear and listen for pinking. Really make the car labour more than usual. If no pinking, rotate the distributor a little anti clockwise. Try it again until you eventually hear pinking. Then rotate the distributor clockwise to just stop the pinking. This is the optimal advance for the car at its current condition.
ReplyDelete