Working on the SM

Success, I have managed to get the rear seat entry release handle off the front seat and the seat back is removed.

I wedged the side of the seat away from the frame so that I could slide the spring steel cylinder over to reveal the clip slot. I thought the clip was going to be difficult to remove but I was easily able to slide it off and then the handle pulled straight out. As the handle shaft has a tapered end on it, all I think I have to do to get the handle back on is to replace the clip in its slot, slip the spring cylinder back over it to hold it in place and when I have the seat back back on, push the handle back in until the clip clicks into place.

All the yellow crumbly stuff on view is the decayed remains of either seat padding or the foam in the composite velour material.

Cheers, Ken

Seat Bush Clip Slot Revealed.jpg

Seat Handle out.jpg
 
Thanks for the photos Ken re taking those seat handles off, I’ve never attempted that myself.

Re the speakers I fitted new ones recently and was surprised how good the 3 speaker system is, at least from the drivers seat. I fitted two 8 ohm speakers in parallel on the left and a 4 ohm on the right, driven by a small Bluetooth amplifier. There are plenty of 4 inch 4 ohm speakers to choose from, but finding good 8 ohm ones was a bit more difficult.

To gain access I undid the back seat, pulled it forward a bit with the front seats fully forward, then took the rear side panels out, replaced the speakers and refitted - a bit awkward initially but easy enough overall. It’d be nice to fit a speaker on the front right, but I don’t think theres enough space.
 
I have to report that the speaker boxes I spend lots of 2020 making and fitting are a great success. I fitted them to the sloping face of the panel just in front of the front door opening. This panel provide a natural small speaker box which I filled with an acoustic wadding. The case was designed to have the speakers also sloping upwards so the net effect is that both speakers are in direct line of sight of the driver and within a 30 degree axis of the tweeter cone. With a little bass boost on the 4 inch speakers and clear un-interrupted treble, they sound quite good. They even make the 5 inch speakers I managed to squeeze into the back seat side cards a bit redundant even though they have much better bass built in.

At least this helped me retain the feeling I was achieving something for myself while I was assisting young Ken (AXGT) with his GS restoration.

Cheers, Ken.

Front Speaker Mounted LHS.jpg
 
So about once a year, my SM turns into a non-starter. If I start it up and go for a drive, it seems OK next time but if I start it up to do some work on it, on restarting it soon after, it will only fire on a couple of cylinders but usually not enough to get it going and then no cylinders at all. The cure for this is to take the spark plugs out and give them a clean off to get rid of the oil and soot and then with some help to the battery, it fires up on all cylinders. I have been using NGK BP6ES spark plugs as indicated by the NGK fitting guides but I note that Gerry Hathaway recommends BP5ES plugs. Do you think this would make a difference?

I also noticed a few other issues with my ignition system, I have Champion spark plug leads fitted which I measured at 15000 ohms on the long ones rather that the Bougicord spec of about 1000 ohms. Seeing that the rotor has 5000 ohms built in and the Bosch coil leads are about 1000 ohms that totals up to 21000 ohms rather than 7000 ohms max original spec. So do people think that could be a contributor to my issues? It looks like I need to source a new original spec set of HT leads.

Also the carbon brushes in the dizzy cap for the rotor are worn out so I will have to find some replacements 5mm diameter and about 6mm long. Any ideas where to source these?

Anyway, I fitted and got working my replacement capacitor holder block with working vacuum retard capsule and for the first time, I got to see the spark advance working properly. 0 degrees advance at idle with a jump to 10 degrees advance as the throttle opens and 22 degrees advance at 2000 rpm at the strobe setting point.

To add insult to injury, when I crawled under the car to retrieve a spark plug from between an exhaust shield and the body, I found a pool of LHM under the brakes on one side and very greasy mess around one of my Rzeppa driveshaft CV joints. I have deduced that these CV joints use a CX boot but does anyone know the technique for replacing the boot seeing the large ligarex band is within the wheel bearing housing? Also, is it possible to replace the front brake caliper seals without having to take the caliper right out of the car (which looks like a large job)?

No Cheers, Ken
 
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If you are talking about the outer boot, I believe you will have to disconnect the driveshaft from the transmission, replace the boot (and ligarex band) then work the boot and ligarex band through the pivot. If you are talking about the inner boot, I made a handy tool from a cheap pair of Chrysler banding pliers by bending it at 90 degrees. This tool allows me to reach in parallel to the driveshaft to close the Ligarex band. I chose the Chrysler tool because (a) it was cheap, so if I broke it, I would be not too distraught; and (b) since it was cheap I assumed correctly that the metal was not of a very high temper and therefore could be bent easily without fracturing.
ligarex 90 tool.JPG
 
Hi Ken,

Andrew Brodie likewise recommended BP5ES plugs to me - which I use (when I'm not using BP5RES)

I think they foul up a little less….?



Regards,

Rhys
 
I used to have a hot start problem like that Ken until I replaced the ignition leads. I fitted some for a Range Rover V8 about 10 years ago and have never had a hot start problem since. That said it’s important to floor the throttle and hold steady until the engine fires.

Re the carbon brushes in the distributor cap, IIRC they’re the same as in a VW Beetle cap.
 
Hi Folks,

I guess it is time for another lockdown update on SM progress.

Thanks for the suggestions above, they have been very helpful. My SM is still off the road but I have taken quite a bit apart and will hopefully start putting it back together in the next few days. Hopefully our lockdown will lift on Sunday.

I have bought a few ignition bits online, 12 new BP5ES sparkers (AXGT will get a swag of BP6ES plugs for his GS) but the first 6 are not installed as yet. I purchased a Bougicord spark plug lead set from Citroen Classics. I was assured these were original spec leads but when they arrived they are about 3 times the resistance listed in the 581-1 manual but I guess that is a big improvement on 15 times the resistance.

I managed to track down some new carbon brushes for the dizzy cap and found that a Robert Bosch Australia part #1 234 321 000 fits really well, even into the original springs.

But the big purchase has been a whole new dizzy from 123Ignition that you can connect to your phone via Bluetooth and program into it whatever centrifugal advance and vacuum advance/retard curve you want to and you can even advance or retard the ignition on the run to see what happens.

https://123ignition.com/product/tuneplus-6-r-v-sm-ie/

I also have new caliper seals to fit and a new boot for the driveshaft. I managed to separate the Rzeppa joint using a slide hammer bolted to the end of the driveshaft. I was able to easily remove the brake caliper after removing the aircleaners and tray and then accessory drive tray and support rail. Pics to follow.

Cheers, Ken
 

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I thought I would document my Experience with a few Citroen SM IE Ignition Systems

I bought my SM IE about 5 years ago, and I have been fighting with the ignition system since then. Initially it was fitted with the stock standard dual points ignition system but I think it had been fitted with replacement ignition leads. The engine was running quite poorly initially especially at low revs, so I decided to check the timing. In the IE, the timing light hole is shrouded by the intake plenum and there is a hydraulic pipe that runs right in front of the hole. My old 1970s Archer/Tandy timing light was not really up to the task, so I purchased a new current technology timing light. On testing it seemed that the engine had set to fire at PMH at 2000 rpm rather than the 22 degrees as required in the specifications. Resetting the timing improved the low speed torque but the engine was still not running well.

WORKING WITH THE ORIGINAL POINTS BASED SYSTEM

To start with, I looked at the dual points cassette and wondered how on earth do you set the points gap, especially on the lower points. (I have since found there is a special tool for adjusting the points gap on the original cassette but I found that out after I had moved on from this type of cassette.) I also checked the points capacitors and found that they both had adequate capacitance but one was down on insulation resistance. I then noticed an updated points cassette on some overseas website that had some knurled knobs with an allen key hole in the middle that looked as though it would make the adjustment process possible without having to remove the points cassette for each adjustment, so I ordered one of these and two replacement capacitors at great expense.

About this time, I also realised that as well as timing cylinder 1 on Bank A of three cylinders, it was necessary to also synchronise the two ignition systems so that cylinder 6 on Bank B that was controlled by the other points and coil, fired at the correct point on the flywheel. Luckily my flywheel has markings for the TDC or PMH points for all cylinders. The only way this could be achieved was to time cylinder 1 to fire at PMH and then swap the timing light pickup to cylinder 6 and see if I could see the 6 PMH mark through the timing hole. If adjustment is required, the dwell on the bank B set of points is adjusted until cylinder 6 is firing at 6 on the flywheel. The final step of the timing is to change the pickup for the strobe to cylinder 1 and rotate the distributor (with vacuum capsule disconnected) to fire number 1 at 22 degrees at 2000 rpm. Once the distributor is locked in place at this point, you should be able to then observe the advance curve continue its rapid rise to about 2400 rpm, then have a gentle rise onto 4000 rpm and no advance beyond that.

My distributor didn’t seem to have this centrifugal advance characteristic and rose quickly to max out at some value which I couldn’t read, and stay there for the rest of the upper rev range. I have never worked out why my stock distributor did this centrifugal advance. The IE unit seems to be fitted with equal springs and the weights move out as the revs rise until they hit some solid rubber bounce blocks. This seems to accord with the advance curve that my car has but it leaves a huge hole in the torque output around 3000rpm such that you would never start an overtaking move at less than 4000 rpm. On full throttle at 3000 rpm, the engine felt weak, and as you lifted the accelerator, the engine torque increased quite markedly at first before starting to decrease with further lifting of the throttle. After some thought, I decided the ignition was running quite overadvanced for full throttle performance at 3000 rpm but was more optimally advanced and gave good economy for part throttle cruising at say 3000 rpm in 5th or at about 100kph.

Jerry Hathaway has shown that two holes can be drilled through the centre of the capacitor block so that a 3mm allen key can be inserted into the newer points capsule adjustment wheels allowing the points gap to be adjusted with the engine running. There is a youtube video of him showing such an adjustment. But ultimately, I have found with a worn distributor, you can set it up correctly and it runs well initially but still loses tune very quickly.



THE LUMENITION EXPERIMENT

After speaking to a couple of aussie SM IE owners that were using Andrew Brodie recommended Lumenition units, I decided to try one of these to see if this get around the setting dwell and timing issues that I have outlined above. I managed to find someone with a used system that they had replaced with a John Titus distributor, so I purchased this. The engine was way retarded with I first started it but came good when the distributor was advanced. I then checked the bank synchronisation and it was way out. I ended up having to extend the adjustment slot for the second optocoupler by quite a way with a file to get Bank B anywhere near synchronised with Bank A.

I tried both the standard Lumenition coil drivers and some “smart” silicon chip (SC) units but settled on the Lumenition units because the others were not reliably firing the coils despite a very clean signal from the optocouplers.

COIL PROBLEMS

The car still has the original Ducellier coils with ballast resistors. Both coils will throw quite a good spark as was shown by using the SC units in test mode, however the car was starting to miss when I was caught in traffic and the engine was hot. The car would easily stall when the idle dropped to a stage where the alternator stopped charging the battery and was very difficult to re-start. This fault would clear after a short run on a freeway.

Investigations showed that when the car was cold, the coils still had a nine volt supply after the drop across the cold ballast resistors, however when the car was hot and the ballast resistors hotter (and therefore much higher resistance), the coil drive voltage had dropped to less than 6 volts. I think there is just not enough output from the coil to make the plugs spark, despite running the ignition from a new relay switched supply. To test this theory, I soldered a 5 diode string across the ballast resistors to give the coils a more constant 9 volt supply and the hot running problem went away completely. I think this issue could help explain the hot starting problem that all SMs suffer from.

VACUUM RETARDATION CAPSULE

On the IE cars, this capsule is supplied with vacuum from the manifold when the butterfly is against the rest stop and its action is to retard the ignition by 8 to 10 degrees to stabilise the idle speed and help with idle and overrun emission levels. As soon as the butterfly is activated, the vacuum supply is switched to air cleaner pressure and the capsule allows ignition to advance to about 9 degrees BTDC before the centrifugal system adds more advance as engine speed increases.

On my car, this capsule had developed a substantial leak in the diaphram that prevented it from working and the manner of construction did not lend itself to an easy repair. I managed to purchase another damaged block with an OK diaphragm and I have got that to work. Also, because the vacuum capsule is used for this retardation purpose, there is no ability to give the engine any vacuum advance when it is working on light throttle to improve economy.

SINGLE COIL SYSTEMS

The big advantage of single coil systems is that the odd fire configuration is built into the distributor and if designed correctly, the synchronisation of the banks never needs to be adjusted again. The disadvantage is that at 6000 rpm, the system only has 2.5 milliseconds to recharge the spark energy system between half of the ignition pulses. The other advantage is that it reduces the ignition current requirement to a minimum of half of that required for a dual coil system thereby reducing the load on the battery during starting and running at idle.

MY IDEAL SM IGNITION SYSTEM

  • A non-contact solid state engine position sensing system so ignition timing and bank synchronising is set and forget (within reasonable limits).
  • A single coil system with adaptive coil charging or CDI so that load on battery is reduced to the minimum required to produce a satisfactory spark to 6500 rpm.
  • Easily adjustable multi-breakpoint centrifugal advance system so the engine can be tuned for full throttle torque.
  • Easily adjustable multi-breakpoint vacuum advance system so that tuning can be adapted for economy in partial throttle settings.
  • The ability to monitor ignition system inputs and performance while driving the car.
The re-released 123 Ignition , tuneplus SM Distributor provides all the above features but does it live up to its promise? Stay tuned!

Cheers, Ken
 
Hi Ken,

It will be no surprise to you that I’m keenly awaiting the outcome here.

My transition from points – to Lumenition – to the Pertronix conversion has not been without a degree of trauma.

The Pertronix conversion has overwhelmingly been the best option to date, but it lacks the vacuum retard connection.

I had imagined that, one day, I’d install an ignition management module to provide some accuracy to overcome any potential ignition curve shortcomings. (probably never going to happen)

I do have one of the early 123 SM distributors. I’ve never tried it. There was some talk about them overheating.

This re-release by 123, may provide the best solution to date?

Regards,
Rhys
 
Does the vacuum advance really matter that much? it only advances the ignition at low throttle openings..... Its there more for fuel economy that anything I've read in the past. If your driving an SM, I imagine smooth running and performance is much more important than optimising fuel economy :)
 
Not at the price petrol is heading at the moment. I suppose I will have to start writing the next chapter which will contain some interesting observations on the factory centrifugal advance curve.

Cheers, Ken
 
Does the vacuum advance really matter that much? it only advances the ignition at low throttle openings...

Actually a vacuum retard - rather than advance. It's been my experience that (generally) these do make a difference - and that manufacturers rarely go to the expense of adding something without sufficient cause.

Pertronix without a vacuum retard system, works much better for me than than points or Lumention with a retard. I suspect the whole lot will work better with electronic control or modulation.

It's not like there isn't a few other technical issues to ruin your day while driving a SM.....
 
Actually a vacuum retard - rather than advance. It's been my experience that (generally) these do make a difference - and that manufacturers rarely go to the expense of adding something without sufficient cause.

Pertronix without a vacuum retard system, works much better for me than than points or Lumention with a retard. I suspect the whole lot will work better with electronic control or modulation.

It's not like there isn't a few other technical issues to ruin your day while driving a SM.....

Vacuum retard..... How does that work? You don't want to retard the ignition at high vacuum --light throttle (unless you are running boost so looking for high pressure ).
 
Hi Shane,

If you read the paragraph about vacuum retard capsule in my post 149 up the page, it explains why it is there as far as I can discern. I think the US SMs had these fitted as well for pollution control issues.

I am almost finished writing the post about how I am going with the 123 distributor. But SWMBO washing machine has indicated that it can't empty its water so I have to fix that first. I have spotted the problem, there is a 50 cent piece acting a valve on the drain line stopping it emptying! It looks like we are in for another swim around the Laundry floor.

Cheers Ken.
 
As far as I know, no US model SMs came with vacuum retard (or vacuum advance). I believe that only EFI cars got the vacuum capsule and we didn't get any of those here. I experimented once with adding vacuum advance (spark advance at high vacuum - i.e. cruise, deceleration and idle). It was impossible to implement on a 5-speed car because the idle vacuum was too close to cruise vacuum. I was able to implement vacuum advance on an automatic because in drive, the vacuum of the engine loaded by the torque converter was sufficiently below cruise vacuum that the engine didn't runaway. If you left it in neutral for any length of time, however, the idle speed would run away to about 2K rpm.
 
Hi John,

The 123 does have an RPM setting under which it does not apply vacuum advance. With this set at 1500 rpm, it does not seem to cause runaway in the trial tests that I have run so far. It might even be able to be set lower than 1500 too.

Cheers, Ken
 
As far as I know, no US model SMs came with vacuum retard (or vacuum advance). I believe that only EFI cars got the vacuum capsule and we didn't get any of those here. I experimented once with adding vacuum advance (spark advance at high vacuum - i.e. cruise, deceleration and idle). It was impossible to implement on a 5-speed car because the idle vacuum was too close to cruise vacuum. I was able to implement vacuum advance on an automatic because in drive, the vacuum of the engine loaded by the torque converter was sufficiently below cruise vacuum that the engine didn't runaway. If you left it in neutral for any length of time, however, the idle speed would run away to about 2K rpm.

Don't the carbies have a vacuum port that closes when the idle circuit is in play ? The vacuum advance needs to go to the connection on the carby that only sees manifold vacuum when the accellerator is open ( do they call it ported vacuum or something like that ? ).

I'll go back and find the post about vacuum retard. Sounds very strange :)
 
Don't the carbies have a vacuum port that closes when the idle circuit is in play ? The vacuum advance needs to go to the connection on the carby that only sees manifold vacuum when the accellerator is open ( do they call it ported vacuum or something like that ? ).

I'll go back and find the post about vacuum retard. Sounds very strange :)
Never seen one here in the states on a US model, and I have seen quite a few. Every Dizzy I have seen (and I have a box full of them) has the cassette carrier without the vacuum cannister. The parts manual indicates that all 2.7 engines except IE got the non vacuum dizzy. It also has a special part number for the USA 3.0 dizzy, then it has a vacuum retard dizzy for EU 3.0 engines. Since EU 3.0 were all automatics, perhaps the vacuum retard dizzy was supplied with EU 3.0 automatics as well as the IE 2.7. I haven't seen any EU 3.0 automatics here (we got plenty of USA automatics), so I can't say for sure.
 
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