The stuff nightmares are made from

Alan S

Well-known member
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Mar 4, 2001
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Queensland, Australia
I have just managed to almost drive myself crazier than normal by trying to tune the motor on my CX. It's fitted with a Magnetti Morelli?? (I think subconciously my brain is trying to make me forget the name as I tend to get traumatised every time I think about it) distributor. As a first time effort with no paperwork to guide me (thanx a lot Mr Haynes
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) it was a bloody nightmare particularly when I lost all spark, #1 son had the big 17"ers off his, the 16V was stuck in behind both cars & #2 son was on the phone screaming to be picked up from work!! With the use of a multi-meter & a Lumin engine analyser, I found it to be a fairly simple task, but without both of those, it wouldn't have been a case of what we were in but more a case of measuring the depth
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Here is what happened as I described it on another forum. Don't know if anything apart from CX c-matics have the thrill of being fiited up with one of these but if so, it may be some help to you.
if you want a thrill, take a Magnelli Magenta or some silly bloody named thing distributor out & try to set the points. None of this stick a feeler gauge in & adjust; no sir, these have a thumb screw on the side which presses on a plate which in turn pops the doo dah in that hits the lobes on the shaft below the rotor button & causes the points to open. Just a couple of little things though; you can't fit a set of feelers in there, if you could you wouldn't see the points when you put them in, you can't see when the lobe is hitting the fibre block on the moving contact, you can't see the points once they are in the distributor & to see them you have to pull them from the distributor so by this stage you haven't a clue what the setting is.
If you are lucky enough to have one of these & have been charged mega-bucks to have the points checked then; get hold of a multi-meter & prise the top off the small insulation block at the top of the condensor. Disconnect the power supply lead to the condensor & keep adjusting the thumbscrew adjustment until you get an open or closed circuit. Fit up an engine analyser; (Lumen or similar) & wind motor to see if the points are opening & closing. If not, turn the thumbscrew in the opposite direction to that which you were to get the first reading, but ever so small amount, until you get make & break. Reassemble the distributor (button, top & lead to condensor) & start the car. Test dwell angle which should be 55. In my case it was 70 which went to 80 & then had to be adjusted back to exactly 55. To reduce the number, turn the thumbscrew anticlockwise looking from the passengers side of the car. No more than 1/4 of a turn at a time.
Checked with Haynes manual for some guidance (don't know why? Must have been getting desperate ) & found mention of the brand at the start of the ignition section & thereafter treated as the 3 wise monkeys; gee I wonder why??
If anybody has one of these distributors I hope this is some help. They must be a bit rare as I have/had 5 CX's & this is the first time I have seen one. Sounds like a good argument for fuel injection.

Alan S
 
Hi Alan,
I think I would be tossing that disy by now, I have lots of good Ducellior units out of c-matics that fit straight in. Those Mirelli Distributors are very rare, I can remember ordering 6 sets of pionts about 15 years ago to put into stock, I'm pretty sure I still have them.

David.
 
David,

The beauty of this thing is that with a spotlight & of course the mandatory bi-focals, I had a look at the points & although they obviously had a bit of age on them, the contact surface looked as though they had just come from the factory. The dissy from memory is marked I think "LA2 " from memory but Haynes seems to get VERY lost with anything mentioned about them. Are you aware of any figures available which would show the amount of advance which should be happening at varying revs brought about through the vacuum advance??
Although they are a bit of a "challenge" once you start setting to dwell angle as opposed to the old feeler gauge & screwdriver system, they do give an accurate result.
Out of curiosity, could someone tell me also why every Citroen Weber carby I pull down rarely if ever has the correct jets in as shown in Haynes & why you can get 2 identical cars both with differeing jet sizes & can someone please tell me what those jet sizes are supposed to be from a source other than Haynes for a '79 CX 2400 C-matic??
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Alan S
 
Hi Alan,

you want something to make you crazy and frustrate the hell out of you?? I send you a DS injected car that doesn't run, that's had someone else tamper with EVERY setting possible, every wiring harness opened up and played with, the computer in bits full of leaves, missing injectors, modification here and there and no standard to car look at and reference back to..... Would you believe I've cursed at it once or twice
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I'm starting to get it back to what it should be though...

seeya,

Shane L
 
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